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EE 477 Final Report

1. Environmental Factor 10 Ground Mobile Failures 10 hours 447 744 2233 42 hours 255 years These results and calculations are derived for the worst case scenario for each component To get these results is assumed to be at the maximum operating temperature before the component burns up and no longer works That is why the MTTF is relatively low If we used a more conservative temperature value to calculate MTTF for the LDO and boost converter such as 35 0 23 the MTTF would increase to nearly 250 years for both chips and 230 years for the microprocessor Along with the assumption of maximum operating temperature I assumed a 300 amp current draw on the IGBT If more reasonable values were chosen such as a temperature and current draw such as 100 C 0 38 and 50 amps respectively the MTTF would increase to 94 years By using values for that are in a more reasonable range the MTTF for these critical components drastically increases Based on the operation at lower temperatures the reliability of each of the critical components is acceptable 5 3 Failure Mode Effects and Criticality Analysis FMECA The schematic can be broken down into five major functional blocks Appendix A contains the schematics of each functional block while Appendix B contains the FMECA Worksheet which provides information about the different failure modes causes effects and criticality for each of t
2. 4 PONER H DER 2 Team 13 Mata eV Purdue University Spring 2009 D 1 477 Final Report 2008 Figure D 2 Bottom Copper with Silkscreen 4470 FACE 0 135 Moto Purdue Univ D 2 477 Final Report Appendix E Parts List Spreadsheet Fall 2008 Vendor Manufacturer Part No Description Unit Cost Qty Total Cost Honda VF500F Chassis 500 Honda VF500F Chassis 100 00 1 100 00 Mars Electric LCC Mars Electric LCC 0709 48 72 Brushed DC Motor 350 00 1 350 00 Magura Magura THR35 0 5 Potentiometer Throttle 0 00 1 0 00 Surplus Center Grizzly 1 2124 12 D 12 Tooth Front Sprocket 5 00 1 7 53 Surplus Center Grizzly 1 2124 13 D 13 Tooth Front Sprocket 5 00 1 7 53 Surplus Center Grizzly 1 2124 14 D 14 Tooth Front Sprocket 6 00 1 9 04 Sprocket Specialist Sprocket Specialist 424 66 66 Tooth Rear Sprocket 102 04 1 102 04 Tractor Supply Co Tractor Supply Co 1150060 50 Roller Chain 10 ft 27 02 1 27 02 Tractor Supply Co Tractor Supply 1151066 50 Connecting Link 3 99 1 3 99 Batteryspace Battery Chargers 133 00 1 133 00 SVR SVR18 12V 22Ah SLA Batteries 0 00 4 0 00 Microchip Microchip PIC18F4331 PIC18F4331 4 99 3 25 23 Ebay Powerex IGBT CM300DY 24H 25 00 2 62 41 Crystalfontz Crystalfontz CFA 634 YFB KS Serial 20x4 LED
3. 477 Final Report Spring 2009 Team 13 Moto eV Team Members 11 Mike Stuckenschneider Signature Date 2 Loren Garby Signature Date 3 Arin Chakraverty Signature Date 4 Janell Niekamp Signature Date SCORE 6 Technical content Design documentation Technical writing style Contributions Editing Comments 477 Final Report TABLE CONTENTS Abstract 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 0 11 0 12 0 13 0 Project Overview and Block Diagram Team Success Criteria and Fulfillment Constraint Analysis and Component Selection Patent Liability Analysis Reliability and Safety Analysis Ethical and Environmental Impact Analysis Packaging Design Considerations Schematic Design Considerations PCB Layout Design Considerations Software Design Considerations Version 2 Changes Summary and Conclusions References Appendix A Individual Contributions Appendix B Packaging Appendix C Schematic Appendix D PCB Layout Top and Bottom Copper Appendix E Parts List Spreadsheet Appendix F Software Listing Appendix G FMECA Worksheet Fall 2008 Un e e 20 25 29 33 39 41 49 50 51 1 Cd D 1 1 F 1 G 1 477 Final Report 2008 Abstract The Moto eV concept is a full scale electric motorcycle The electric modifications will be retrofitted into a 1986 Honda VF500F ch
4. CKCKkCkCkCk Ck k kk kc k kc KRK KKR KKR KKR KRK KRK ke ke ke e x INCLINOM ADCONObits ACMOD1 1 GROUP D ADCONObits ACMODO 1 ADCHSbits GDSEL1 0 AN3 ADCHSbits GDSELO 0 ADCONObits GO 1 while ADCONObits GO inclin read ReadADC inclin avg 0 9 inclin avg 0 l inclin ETER CONFIGURATIONS if inclin avg 523 amp amp inclin avg 495 val 0 if inclin avg lt 495 1 1 1 lt 87 1 if inclin avg lt inclin volt neg i inclin val inclin angle 87 i 87 13 ERIOD VALU I TO SET PWM FR LCD DISPLAY Fall 2008 EQU ENCY TO 1 477 Final Report else for 1 1 1 lt 87 1 if inclin avg lt inclin volt pos i inclin val inclin angle i 1 97 adc low LCD DISPLAY SELECT if PORTCbits RC5 0 if prev lcd state 1 prev lcd state 0 putrsUSART 1 10 0 1 lcd 1 if prev lcd state 0 prev lcd state 1 putrsUSART DelaylOTCYx 0 lcd disp2 14 2008 477 Final Report Fall 2008 Appendix G FMECA Worksheet VCC shorted Bypass No Power to Medium Causes entire system to ground Capacitor Shorts Microprocessor to shutdown A2 Micro Reset swi
5. dq GROUP 0 1 11 0 ANT 0 1 1 its GO batt4 read ReadADC F 6 Fall 2008 477 Final Report batt4 avg 9 batt4 avg tbatt4 read 10 batt4 avg batt avg batt4 batt4 div batt4 disp batt4 avg 1 612 COASTING RK RK KK KK kk KK KK I KK I kk ko ke kk koc ke ke ke ke ke This function lets the motor slowly decrease in a coasting fashion It is solving the problem of the motor doing the equivalent of an engine break when the throttle was released CKCKCkCkCkCkCk kk kk kk kk kk kk kk kk kk kk kk ck k ckck ck ck void coast void if throttle avg prev gt throttle avg PORTDbits RD1 0 PORTDbits RDO 1 else PORTDbits RD1 1 PORTDbits RDO 0 LCD INITIALIZE KKK RK KK KK I KKR KKR KK KK KRK ek This is where the LCD is initialized It hides the LCD cursor and clears the display This function is called before LCD display pages are Switched and in the main initialization loop before any display appear OCKCKCkCkCkCkCk Ck k kCk kk kk kk kk kk kk kk kk kk kk ck k ck k ck k ck k ckck ck ck KRK KRK ke x void LCD init void putrsUSART 004 Hide LCD Cursor putrsUSART Nf Clear Display display scaling Fall 2008 477 Final Report Fall 2008 LCD DISPLAY
6. KKK RK Ck Ck Ck KK KK KK This is where the second page of the LCD display is configured It displays the battery charge status of the four 12V batteries that power the motor This function is called in the while 1 loop nested in the main pooling loop Thus it is called once per main loop iteration CK CKCkCkCkCkCk kk kCk kk kk kk kCk kk kk kk kc k kckck ck k ck k ck k ck ck ck ck ckck ck KKR kk ke x void lcd displ void putrsUSART N001N004 Delayl100TCYx 0 putrsUSART Batt 1 sprintf buf S2d ldV r n battl disp 100 battl disp 100 10 putsUSART buf Delayl0TCYx 0 putrsUSART Batt 2 sprintf buf S2d ldV r n batt2 disp 100 batt2 disp 100 10 putsUSART buf 1 10 0 putrsUSART Batt 3 sprintf buf 2d 1dVNrWMn batt3 disp 100 batt3 disp 100 10 putsUSART buf 1 10 0 putrsUSART Batt 4 sprintf buf 2d 1dV batt4 disp 100 batt4 disp 100 10 Delayl0TCYx 0 putsUSART buf void lcd disp2 void F 8 477 Final Report putrsUSART 001 004 DelaylOTCYx 0 INCLINOMETER putrsUSART Lean Angle sprintf buf 2u inclin val putsUSART buf 1 10 0 putrsUSART 036 001 200 DelaylOTC
7. infringement should not be an issue Electric Bicycle Most of the defining characteristics of the electric bicycle patent do not interfere with the key aspects of Moto eV The part of the electric bicycle that would give the most incentive to file a case of patent infringement would be the power control system The system on the electric bicycle is controlled using a mechanically actuated switch though which is substantially 17 477 Final Report 2008 different than having digitally controlled power switch Most other aspects of the bike can be dodged easily enough since Moto eV will be a single gear motorcycle with no regenerative battery charging system removing any conflicts with a clutch based motor drive or battery charging methods Electric Motor Controller This patent will fortunately play no role in patent infringement since it was filed over twenty years ago Microprocessor Motor Controller Having Discreet Processing This patent is worded in a manner that makes it sound like it is used for large scale multiple device motor control mechanisms The motor control is accomplished using a microprocessor that uses its outputs to signal outputting power and uses its inputs to read a variety of sensors providing feedback information to help control the motor apparatus The second main point in this patent essentially summarizes the principle of an interrupt service routine There are different motor control tas
8. 1 lt i me pm DIA 5 7 8 DIA 2 15 16 Figure B 8 Motor Mount 2 477 Final Report 2008 Figure 9 Dash Current Draw LCD Backlight E a 2 D gt 2 93 peedometeg 2 LCD Display NY Switch 2 4 Odometer Reset Ride Mode 24 5 477 Final Report Fall 2008 Figure 11 48V Battery Bank Chargers S 4 7 2 gt 1 4 6 477 Final Report Fall 2008 Appendix Schematic Appendix A Schematic Functional Blocks Figure C 1 Schematic Page 1 x s k 12 9 Rs SW PUSHBUTTON SPST 2 10k MCLR D IMCLAVpp RE3 ww REzKBIsPGD XPGD 2 RAo ANo RBsKBIVPGC 38 PGC 52 24 Li Shunt Rasister QUT rel ICAPATINDX RE4KBIoPWMs 54 RAs ANaV rel CAP2 OE A FBSPWMS RA4 ANA CAPSICEB RASANSILVDIN FBU PHMI m REANG Ride Mode REWANT Vdd Brakelight RE2 AN amp RIDE MODE BREAKLIGHT RDz PWMz AVes 2 m lt OSCHCLKVRAT LCD 0 MH oscacukomas RD4IFLTA RcaT10S0rTiCKI RCTIRXIDTISDO T nne lt CE1C2 RACWTIOSICCPZIFLTA 5 Lo Gate J RCS NT
9. 139 144 750 756 762 767 1713 119 784 789 194 800 805 810 814 819 824 829 833 837 842 846 850 854 858 862 865 869 872 876 879 882 885 888 891 894 896 899 901 903 905 907 909 911 913 914 915 917 918 919 920 921 BATTERY VARIABLES unsigned int battl read 0 unsigned int batt2 read 0 unsigned int batt3 read 0 unsigned int batt4 read 0 unsigned int batt micro read 0 unsigned int battl avg 0 unsigned int batt2 avg 0 unsigned int batt3 avg 0 unsigned int batt4 avg 0 unsigned int batt micro avg 0 F 2 477 Final Report unsigned int batt micro disp 0 unsigned int battl disp 0 unsigned int batt2 disp unsigned int batt3 disp unsigned int batt4 disp 0 0 0 unsigned float batt read 0 unsigned float sum batt 0 unsigned float batt average 0 Fl DISPLAY VARIABLES char buf 6 0 0 0 0 0 0 TIMER VARIABLES int tim_cnt 13 PRAGMA CONFIGURATIONS pragma config OSC IRCIO pragma config WDTEN OFF pragma config PWRTEN OFF pragma config BOREN OFF pragma config LVP OFF INTERRUPT VI ECTOR internal oscillator turn off watchdog timer turns off the power up timer turns off the brown out reset turn off Low voltage programming KKK KK KK KK I I KRK KK KK KK KRK This is the function that specifies where the interrupt vector is and which memory address in the code to proceed to when
10. E unsigned int throttle_read 0 unsigned int throttle avg prev 0 unsigned int throttle avg 0 throttle 6 0 0 0 0 0 0 1 2008 477 Final Report Fall 2008 unsigned int sum throttle 0 int 1 0 unsigned int duty cycle unsigned int dutyH unsigned int dutyL unsigned float throttle disp SHUNT VARIABLES unsigned int shunt read 0 unsigned int shunt avg 0 unsigned int shunt disp 0 unsigned int sum shunt 0 INCLINOMETER VARIABLES unsigned int inclin read 0 unsigned int inclin avg 0 unsigned int inclin val 0 rom unsigned int inclin angle 87 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 14 75 16 771 78 79 80 81 82 84 90 90 90 rom unsigned int inclin volt neg 87 102 103 104 105 106 108 109 110 111 113 114 116 118 120 122 124 126 129 131 134 137 140 143 146 149 153 156 160 163 167 171 175 179 183 188 192 196 201 206 211 215 220 225 231 236 241 246 252 258 263 269 275 281 286 292 298 305 311 317 323 330 336 343 349 356 362 369 376 383 389 396 403 410 417 424 431 438 445 452 459 466 473 480 487 495 502 509 rom unsigned int inclin volt 861 516 523 530 538 545 552 559 566 573 580 587 594 601 608 615 622 629 636 642 649 656 663 669 676 682 689 695 702 708 714 720 727 133
11. Week 6 was when I started looking at the coding scenario in greater detail I read so many manuals and user guides over the course of the semester that it 15 quite ridiculous I read the MPLAB C18 Compiler Guide MPLAB User Guide MPLAB C18 Getting Started document almost all of the PIC18F4431 datasheet and the C18 libraries document At first it seemed to be pointless but as I started coding and learned how to code using the MPLAB compiler I noticed that my readings played a huge role in understanding how to configure the C code used to program the PIC microprocessor Weeks 6 8 were spent doing examples on the development kit to understand the inner workings of the MPLAB compiler I installed the IDE onto my personal laptop and did a lot of work to understand how to set up the interrupt service routine and timer interrupts to run the code for our microprocessor Then I put my time into trying to figure out how to read inputs from the ATD inputs This gave me quite a bit of trouble and it took some time to get it all working properly I used to the adc h header file but then learned from the microchip forums that the adc h file doesn t properly apply for the PIC18F4431 A 2 477 Final Report 2008 By the time week 11 and 12 rolled around I was getting a great grip the code had the main structure for motor control software written up It was composed of the timer being run off the internal oscillator to drive high a
12. but a motorcycle does not need to run in reverse Next a half bridge was considered 2 switches but this was decided against because regenerative braking will not be implemented A single switch will lower cost and still provide ample performance Half bridge IGBT modules rated at 300A are used due to their cost and because they are much more common than single switches However only the top switch is controlled while the bottom switch is grounded LCD To interface with the rider a large 20x4 backlit LCD 1s being used 31 This provides data such as battery level lean angle and throttle position The LCD interfaces with the microcontroller through a USART connection The LCD module has built in serial communication chips so it was relatively simple to interface with using the built in USART functions 35 477 Final Report 2008 8 3 Hardware Design Narrative Once it was clear what sort of pin each part of the circuit needed the microcontroller pins were all chosen based upon their physical location Due to noise it was attempted to keep all of the analog inputs far away from the high frequency switching ports The ATD module is used extensively for reading all of the system s sensors and inputs The 0 5 potentiometer throttle is monitored through input on pin RAO The inclinometer outputs 0 5V based on angle levels and interfaces through RA3 The micro battery monitoring voltage divider inputs on RA8 This circuit w
13. module Majority of the monitoring process will be done using the ADC module The PIC18F4331 has 9 A D input channels and can perform conversions at up to 200 kilo samples per second which is a high speed rate that is perfect for our motor control application The ADC result is a 10 bit value with 8 bits stored in the low result register ADRESL and the other 4 bits stored in the lower nibble of the high result register ADRESH The ADC will be interrupt driven through an interrupt service routine ISR Each time an interrupt takes place the ADC inputs for the throttle and current sensing shunt resistor will be read and every 10 times an interrupt takes place the less volatile ADC inputs will be read The throttle and shunt inputs will also be averaged using an array 5 index deep since these values will be quite staggered A conditional loop with a counter will be used to check when 10 timer interrupts have taken place to allow the reading of the low priority devices At that point the counter will be reset back to the starting counter value and repeated The components which will involve ADC are the throttle current sensing shunt resistor circuit inclinometer and battery monitoring circuits The CPP module will tentatively be used for getting the motor speed from an optical sensor watching the front sprocket The front sprocket will be painted black and white to correspond to high and low states digitally The speed of the switching will be u
14. 23 Zero Motorcycles Zero X Online Document cited 10 February 2009 http www zeromotorcycles com zero x php 24 NPC Robotics Product Information NPC B1812 Online Document cited 6 February 2009 25 VTI Technologies SCA61T Inclinometer Datasheet Online Document cited 7 February 2009 http www vti fi midcom serveattachmentguid 53b76612850a127b88947edbf1de536f SCA61T inclinometer datasheet 82619004A pdf 26 Fairchild FOD3150 Gate Drive Datasheet Online Document cited 7 February 2009 http www fairchildsemi com ds FO FOD3150 pdf 27 Fairchild FMG2G150US60E IGBT Drive Datasheet Online Document cited 7 February 2009 www promelec ru pdf FMG2G75US60 pdf 28 National LM340 Voltage Regulator Online Document cited 19 February 2009 http www national com ds LM LM340 pdf 29 International Rectifier IRS2117 Single Channel Driver Datasheet Online Document cited 19 February 2009 http www irf com product info datasheets data irs21 1 7pbf pdf 52 477 Final Report Fall 2008 30 Powerex CM300DY 24H Dual IGBT Module Online Document cited 19 February 2009 http www datasheetcatalog org datasheet powerex CM300DY 24H pdf 31 Crystalfontz 632 5 LCD Datasheet Online Document cited 19 February 2009 http www crystalfontz com products 632 datasheets 34 CFA 632_v2 0 pdf 32 International Rectifier IRS2
15. A failure in the boost converter would simply cause the battery monitor to fail A failure of the IGBT s can in the best scenario simply open circuit and shut down the motor Although it could also short and cause 20 477 Final Report Fall 2008 the motor to ramp up out of control and risk causing serious injury to the rider The microcontroller is also highly critical because it is what reads the user inputs and system feedback and determines how to drive the motor If this component fails then the entire system cannot operate The tables that follow are a compilation of the necessary variables and calculations to determine the number of failures per 10 hours and mean time to failure MTTF for each of the previously mentioned components Referring to the model found on page 25 of the Military Handbook Reliability Prediction of Electronic Equipment 36 4p Corg nqni and Mean Time To Failure MTTF 0 4 for microcircuits and microprocessors Therefore these can be used to calculator the failures 10 hours and MTTF for the microprocessor LDO and boost converter In these equations Ap is the number of failures per 106 hours C is the complexity is the junction temperature coefficient is the package failure rate is the environmental constant 15 the quality factor and 15 the learning factor associated with how long the particular component has been manufactured Certain assumptions
16. Gate driver may have burned up Bootstrap capacitor diode failure Bypass capacitor shorts Excessive current draw Motor stops operating Observation Medium Would cause motor to coast to a stop Motor stops operating Oscilloscope Medium Causes motor windings to be shorted Motor stops operating DMM Medium Motor speeds up out of DMM High Can cause serious control injury to rider 477 Final Report Fall 2008 E2 ES Motor seams unresponsive No output Junk to LCD Break light pin Throttle ATD not functioning Buffer overrun dead TX pin Dead I O pin No motor response from user input Pertinent data cannot be sent to the user Causes brake lights no to function Observation Observation Observation High Medium High Can occur while at speed with unpredictable results Can cause user to over discharge batteries Causes bike to not be street legal and increases risk of accident
17. an interrupt takes place f pragma code low vector 0x08 void low ISR void _ GOTO tim ISR fpragma code INTERRUPT ROUTINE KKK RK Ck Ck kk KK kk KK KK KK kk This is the function that takes occurs at the clock speed of 8 plac very time an interrupt hz In this interrupt service routine the adc function is called and the motor function F 3 Fall 2008 477 is called These functions described in greater detail in their respective function headers OCKCKCkCkCk kCk Ck k kk kk kk kk kk kk kc k kk kk kk ck k ck ck ckck ck ck ckck ck ok ke ke ke x interruptlow tim ISR void tim ISR void adc high motor INTCONbits TMROIF 0 CLEAR TIMER INTERRUPT FLAG RK RK KK KK KKR KOKK KK This is where the high priority analog to digital inputs are read The high priority interrupts were chosen according to the importance of their real time value To know that the micro battery and throttle input are accurate value
18. are 8 x 6 5 x 3 5 and weighed in at 18 8 pounds each Motor Originally this project was going to implement a brushless DC motor 8 These motors would be the best for this project because they offer high efficiency and zero maintenance Due to complexity of control limited available motor options and cost the team has decided to use a brushed PM DC motor The rest of the system is designed around the motor choice so the only motor constraints are efficiency weight operating voltage and cost The best motor for this project is the Lynch Lemco LEM 200 D127 9 This brilliant motor can operate between 48 and 72 volts It offers a rated power of 12 56kW 16 84 electric hp at 72V and a rated continuous current pull of 200A At 48V the motor should output 8 55kW 11 46 electric hp continuously and 33 3 N m of torque These motors can also achieve an amazing peak efficiency of 90 Another benefit to this motor is its weight of only 25165 Compared to a series wound brushed DC motor the team was considering this is about twice the power at half the weight The one major downside to using a Lemco is its very high cost These advanced motors cost over 900 shipped to the US This price is after a discount offered to the team by the company owner as well as the exchange rate motors are made in the UK Unfortunately this motor will be out of reach due to the extremely high price 11 477 Final Report 2008 Another motor that
19. control an electric motor from throttle input An ability to monitor battery levels and shut down at a specified level of charge An ability to provide user selectable ride modes An ability to use a tilt sensor to monitor lean angles GU Spo An ability to display pertinent data to rider using a LCD of the Project Specific Success Criteria PSSC were fulfilled with some being more difficult than others PSSC 5 was the first to be completed This proved useful because it provided a means to debug all other issues with software by displaying values and registers to the LCD PSSC 4 was the next to be checked off the list This was the next logical step because the inclinometer chip was already on the PCB and its values could be displayed onto the LCD to ensure proper depiction of lean angle PSSC 1 was then completed This was a large milestone in the project and allowed the team its first chance to take the motorcycle out for a ride In the end voltage control via PWM was utilized for this PSSC This was the most difficult PSSC to complete due to our lack of experience in implementing a real world drive system and issues with our current monitoring circuit Multiple iterations of the final drive system where designed and tested before the final 2 quadrant drive with bootstrap circuit was implemented PSSC 2 was the second to last to be completed The ability to display values to the LCD made this PSSC rather easy The most diff
20. extremely similar in that perspective since there are batteries mounted within the chassis and the motorcycle is indirectly propelled forward by the rear wheel 15 477 Final Report 2008 Electric Bicycle Filling date March 26 1998 According to claim 1 of the electric bicycle patent an electric bicycle is technically a bicycle frame with a high performance lightweight engine mounted onto it The front wheel contains the steering mechanism and the rear wheel must have a hub to accommodate multiple gears The motor is to be powered in conjunction with a variable V belt drive capable of managing a centrifugal slip clutch so that the bicycle can utilize multiple gears The front wheel also contains a regenerative system to charge the battery during use of the bicycle Claim 2 pertains to the final primary function of the patented electric bicycle It is a mechanically actuated power control switch to provide a motor starter power level along with two other power levels during use of the bike Electric Motor Controller Filing date November 11 1986 Claim 1 states that the electric motor controller patent applies to a system that has a current controlled motor The speed of the motor is controlled with the use of an error signal which is based on the difference between the current speed of the motor and a preselected desired motor speed One set of terminals are to be connected parallel to the input terminals to the cont
21. from the motor by adjusting the duty cycle of the PWM output 48 477 Final Report 2008 11 0 Version 2 Changes The main issues that version 1 of the Moto eV had is not being able to coast and lack of current monitoring The combined motor control knowledge of the group was all centered around commanding a certain speed of the motor This however does not permit the motor to coast when zero speed is commanded In fact it causes severe engine breaking that if not done properly could lock up the rear tire and cause damage to the motor A new control circuit can be utilized in order to allow coasting without sacrificing performance Version one utilized a shunt resistor to monitor the current in the armature windings This is not used in the final product due to noise on the monitoring lines and issues with the differential amplifier Version 2 will utilize LEM current monitors which create a closed loop around the armature wire and produce a voltage relative to the magnetic field created when current passes through the armature This is far more accurate and more widely used in industry The second iteration of the bike will also utilize current control This is the industry standard for motor control and allows for more precise control over the torque and current draw of the motor This was not possible to implement in the first iteration because our current monitoring was not accurate enough Utilizing the LEM units an accurate cur
22. in the semester to play around with current control so we moved to a simpler voltage control scheme I wrote the first PWM code but it was changed for the final code to run at a different frequency I wrote a few different averaging routines but the one that I decided to implement in the final software uses a weighted average I also wrote the software to modify the ride mode and select between the two LCD displays During the time I was writing software I was also wiring up the bike Loren and I came into lab and worked on the wiring harness I wired up the rear brake lights to be activated by both the front and rear brakes I also wired up the three switches that are mounted to the front dashboard the headlight the tachometer the fuse block the throttle the IGBT the ignition key the chargers and micro battery Loren tacked the battery monitors the micro battery charger and the main power connection to the pcb Loren and I spent a few days down at the shop painting the bike s bodywork This wasn t necessary for graduation but I feel like presentation 15 important Loren and I primed the tank and painted the front cowl rear cowl front fender side piece battery cage and the tank After everything had been installed in the chassis we ran the bike around for some testing Loren blew out the IGBT gate driver amp bootstrap circuitry He and I spent a long night in lab reworking how we drive our motor The new circuitry allowed the motorcy
23. range transportation device and the method being a motorcycle driven by an electric motor which is powered by batteries A general view will be considered with respect to the motorcycle patent the electric bicycle patent and the electric scooter patent Then a motor control method comparison was made with respect to the electric motor controller patent and the microprocessor motor controller having discreet processing patent Motorcycle Filing date July 25 1986 14 477 Final Report 2008 According to claim 1 of the motorcycle patent motorcycle is a device having fairing and a radiator It must have a longitudinal body with a head pipe mounted to the front of the bike extending back towards the bike The radiator must be placed ahead of the head pipe mounted such that it is perpendicular to the longitudinal axis of the bike Claim 2 then continues to elaborate on how the instrument cluster is to be mounted above the radiator at an upward angle toward the rider and that a headlight is mounted on the front of the bike between the instrument cluster and the radiator The lighting instrument cluster and radiator are all to be covered by a fairing The key claims for infringement would be based on the longitudinal shape and arrangement of the instrument panels and headlights Although much of the motorcycle patent was based around the arrangement of the radiator on the chassis showing promise of substantial difference
24. represents an electrical hazard and a page number for the manual in order to explain the potential danger in greater detail Even though the tank should not be taken off another warning label would be placed on the electronic mounting plate that is located under the tank which holds the PCB shunt resistor and IGBT The warnings would show a picture to represent that some parts may be hot to the touch and represents the possibility of electrical hazard There is also a cord attached to the battery charger so that the bike can be plugged into a wall outlet which will need warning to indicate electrical hazard possibilities The warning would also include a page number reference to the manual to explain the potential danger in greater detail Another ethical consideration is how reliable the battery monitoring system is If for some reason the display was indicating a battery is charged at a higher value than it actually is and a user gets stuck somewhere because of this there would be a problem Therefore numerous tests would be preformed to ensure data values are accurate at all times of the battery charge cycle to maintain accuracy with time The user manual will be the main source of communication between the manufacturer and the customers This will provide the user with crucial information for their safety service information how to drive the Moto eV and troubleshooting information on any type of problem that may arise Due to that fact that Mo
25. team used a Crystalfontz CFA634 YFB KS 11 This is a 20x4 positive screen that has a backlight and a serial interface The team chose this character based display for its ease of implementation A graphical display was an option but due to the scope of the project it was decided to be too ambitious This character display offers the screen real estate required for all of the information the rider will need and will be very simple to interface with A large design constraint was for the LCD to have a positive display so that the rider would be able to view it in direct sunlight Switching Technology Darlington BJT Power MOSFET IGBT amp MCT were all different technologies available for switching the motor The team decided to use an IGBT module based on its low 12 477 Final Report 2008 gate current and low collector emitter resistance separate IGBT module is beneficial in this application due to the power which it must switch and the temperatures that the transistors will reach during peak operation The module architecture being used prevents excessively large PCB traces and in the event that it is destroyed it will not destroy any PCB boards When switching 80V or less 75 to 80 of the time power MOSFET s are used However the high current and the time constraints of this application dictate the use of a sealed module and IGBT technology Fairchild had graciously decided to sponsor the team by providing the hal
26. 117 Single Channel Driver Datasheet Online Document cited 26 February 2009 http www irf com product info datasheets data irs2117pbf pdf 33 Microchip Technologies Inc 2009 IDE User s Guide With MPLAB Editor and MPLAB SIM Simulator Chandler 34 Linear Technology 171529 Online Document cited 9 April 2009 http www linear com pc downloadDocument do navIdzH0 C1 C1003 C1040 C1055 P100 36 D2740 35 National LM2733 Boost Converter Online Document cited 9 April 2009 http cache national com ds LM LM2733 pdf 36 MIL HDBK 217F Military Handbook Reliability Prediction of Electronic Equipment http cobweb ecn purdue edu dsml ece477 Homework CommonRefs Mil Hdbk 217F pdf 53 477 Final Report 2008 37 Appendix Individual Contributions A 1 Contributions of Janell Neikamp The first four weeks of the project most of my time was dedicated mostly to the selection of our components With space and financing being large factors in the selection process we needed to be sure that the motor and batteries would fit within the chassis and be within our price range I also helped with the selection of the microprocessor and IGBT that we ended up finding on ebay I also help with determining our individual Project Specific Success Criteria Once the components were selected I worked on the packaging design First I looked up other electric motor cycles such at the Enertia
27. 2 SCKISCL T mews 07 Rie 18 RCaTOCKITSCKVINTO RC4 NTi SDISDA 7 GPIO2 E RDOTOCKITSCKI RD3 SCK SCL 2 100 GP O1 H 10300 RD2 SDI SDA Tech OUT gt Os D Data Brakelight OUT gt LED Erakalight IN 4 1 477 Final Report 423 HEADER 8 Batt 2 IN Batt 2 IN Batt 1 IN Batt 1 IN Batt 2 IN Batt 1 IN Batt 2 IN Batt 1 IN Batt 3 IN Batt 4 IN Batt 3 IN Batt 4 IN Figure C 2 Schematic Page 2 C 2 Fall 2008 477 Final Report Fall 2008 Figure C 3 Microcontroller Functional Block 5 R9 SW PUSHBUTTON SPST 2 10k 1 4 X Prog MCLR RB7 KBIa PGD 42 lt PGD EC Throttle IN y RAO ANO RBe KBIt PGC 33 Pac LCDBLIN 7 RBS KBI PWM4 PGM Shunt Resistor OUT gt gt RA 2 AN2 Vref CAP1 INDX RBA KBIQ PWMS 2 Batt 3 OUT RB2 PWM2 Batt 4 OUT 5 0 Batt 1 OUT RAS ANS LVDIN RB1 PWM1 Bat 2 OUT REO ANG RBO PWMO RET AN7 Vdd e 1 gt RE2 ANB yss 5 AVdd RD7 PWM7 39 AVss 1 RD6 PWM6 OSCI CLKU RA7 RDS PWM4 OSC2 CLKO RA6 Ay RD4 IFLTA RCO TIOSO TICKI RC7 RX DT SDO RC1 TIOSI CCP2 IFLTA RC6 TX CK ISS RC2 CCP1 IFLTB RCS INT2 SCK SCL RC3 TOCKI TSCKV INTO RC4 INT1 SDV
28. 34 ICSP Programming Entry Pin PGM 38 In Circuit Debugger amp ICSP PGC 39 Programming Clock Pin In Circuit Debugger amp ICSP PGD 40 Programming Data Pin 84 Summary The Moto eV circuitry has been carefully designed to provide the sensitivity required for the analog inputs while simultaneously providing high frequency high noise motor drive signals The two power supplies are designed to provide ample current for the motors as well as the controlling circuitry These power supplies are regulated to stable voltage supplies The microcontroller s analog inputs are filtered and amplified where necessary while the motor control output is optically isolated and amplified via a gate driver The end result is a noise resistant circuit which performs to the team s performance expectations 37 477 Final Report 2008 38 477 Final Report 2008 90 Layout Design Considerations 91 Introduction The Moto eV is designed to be an inner city commuter vehicle with a range of 25 miles and a top speed of around 35 to 40 mph The three major components of the design are the motor drive circuitry and the brain board of these must be designed to mesh with each other in order to create a reliable working product The brain board will accept user inputs in the form of a throttle and other various switches and output to the rider via a Crystalfontz LCD screen 31 The brain board al
29. Backlit LCD 11 00 1 11 00 Digi Key Ohmite TGHGCR0020FE 0 002 Ohm Shunt Resistor 26 31 1 26 31 International Rectifier IRS2117PBF IC DRIVER MOSFET IGBT 3 08 3 9 24 Digi Key Murata Electronics North America 490 2976 Trimpot 20K 1 23 1 1 23 National Semiconductor LM392N IC Op Amp Volt Comparator 1 80 2 3 60 Digi Key Linear Technology LT1529CT Voltage Regulator 6 75 1 6 75 Digi Key Technologies SCA6IT Single Axis 90 Inclinometer 49 16 1 49 16 Digi Key National Semiconductor LM2733XMFCT Boost Converter 3 1 3 00 Texas Instruments INAI43UA Differential Amplifiers 2 36 2 4 72 Digi Key Texas Instruments INA2143UA Differential Amplifiers 3 83 3 11 49 Micro Commercial Co MBR0530TPMSCT Schottky Diode 0 44 2 0 88 Digi Key Stackpole Electronics Inc 1 85 IKFRCT 5 11k Resistor 0 18 2 0 36 477 Final Report 2008 Diodes Inc DFLZ5V1DICT 5 1V Zener Diode 0 44 10 4 40 Panasonic PCC2239CT luF Ceramic Capacitor 0 47 1 0 47 493 1672 180uF Electrolytic Capacitor 0 52 3 1 56 Digi Key Sumida America Components 308 1436 1 10uH Inductor 2 02 1 2 02 Digi Key Lumex Opto Components Inc 67 1357 1 Green Pwr LED 0 16 1 0 16 Digi Key Panasonic P11525CT Blue General LED 0 65 1 0 65 Digi Key International Rectifier IR2302PBF Gate Driver 3 00 2 6 00 Digi
30. Electric Motorcycle EEM and Zero X in order to compare possible packaging These were not to relevant do to the fact that they were designing chassis for the bike and the Zero X had a special patent pending battery supply So Mike and I came up with the current packaging with motor being place right in front of the swing arm while the batteries are right in front of that within the chassis In order to be space efficient I helped cut the out the bottom of tank and scrubbed at the inside to get ride of all the build up that had taken place over the years Then I help cut the top off where the filler cap had been in order to put the LCD display there Once the packaging was planned out and the machine shop was working on the battery cage and electronic mounting plates I started working with the coding a bit First I worked on interrupts that were triggered by the timer overflows and AD conversions to toggles the systems based on user inputs Then I started working on using the high and low priority interrupts so that the high priority interrupt was triggered by the pushbuttons that would switch the direction in which the LEDs were being light up While the low priority interrupt was triggered by the potentiometer which switched the speed of the lights being lit up Then I worked on wiring the bike and adding the batteries in series Once we had the bike working I helped trouble shoot the GPIO which was causing the microprocessor to reset itself do to th
31. Key Tyco A9440 DIP Socket micro 2 64 1 2 64 amp 17 32 1 17 32 Fiberglass Kit 29 62 1 29 62 Self Etching Primer 6 46 1 6 46 Fasteners 5 97 1 5 97 17 35 1 17 35 Degreaser 12 00 1 12 00 New Steering Head Bearings 38 00 1 38 00 Wiring amp Main Fuse 48 95 1 48 95 Total 1149 10 477 Final Report Appendix F Software Listing FUNCTION INTIALIZATION void void void void void void include include include include lude lude include include tim_ adc adc _ lcd ted LCD Moto eV 2009 Completed April 28 2009 Software wriiten by Arin Chakraverty Mike Stuckenschneider Loren Garby Xp18f4431 h delays h timers h lt adc h gt lt usart h gt lt stdio h gt lt stdlib h gt lt pwm h gt define SINGLE_OUT 0b00000000 define PWM MODE 1 0500001100 single output PxA PxC active high PxB PxD active high ISR void high void low void displ void disp2 void init void Interrupt service routine High priority ADC Low priority ADC LCD display page 1 LCD display page 2 LCD initialization int batt avg unsigned int unsigned float void motor void void coast void NARIABL 5 unsigned int prev lcd state 0 THROTTLE VARIABLES unsigned int
32. MOS 101 300 transistors Temperature Factor 58 Linear MOS Max Temp of 125 C Package Failure Rate 0016 4 pin Nonhermetic SMT Environmental Factor 4 Ground Mobile Quality Factor 10 Commercial Learning Factor 1 In Production for over 2 years Failures 10 hours 11 64 85733 88 hours 9 787 years Referring to the model found on page 58 of the Military Handbook and MTTF Gp for high power high frequency bipolar transistors In these equations Ap is the number of failures 10 hours is the base failure rate is the temperature factor is application factor is the matching network factor 20 is the quality factor and is the environmental factor Certain assumptions have been made in order to complete the following analysis The IGBT will be operating at its maximum temperatures Its duty cycle will be greater than 30 it has a JANTX quality factor with a no matching network and is ground mobile The table below is used to derive the failure rate and MTTF using these assumptions and information taken from the IGBT datasheet 22 477 Final Report 2008 Table 5 4 CM300DY 24H IGBT Parameter Description Value Comments Base Failure Rate 2 12 Power output of 750W TT Temperature Factor 2 4 48 1200 Application Factor 2 2 Duty Cycle 3096 Matching Network Factor 4 None Quality Factor 1
33. N TXSTAbits TX9 0 TXSTAbits TXEN 1 TXSTAbits SYNC 0 TXSTAbits BRGH 0 RCSTAbits SPEN 1 RCSTAbits CREN 0 BAUDCTLbits BRG16 SPBRGH 0x00 SPBRG 0x0C Enables 8 bit transmission Tansmit enabled Asynchronous mode High speed baud rate disabled Serial port enabled RX amp TX pins as serial port pins Disables receiver 8 bit baud rate generator Sets high baud rate byte to zero sets baud rate to 9600 PWM INITIALIZATION PTCONObits PTOPS3 PTCONObits PTOPS2 PTCONObits PTOPS1 PTCONObits PTOPSO e PTCONObits PTMOD1 PTCONObits PTMODO PTCON1bits PT lt p PWMCONObits PMODO PWMCONObits PMOD1 PTCONObits PTCKPS1 0 PTCONObits PTCKPSO PWMCONObits PWMEN2 PWMCONObits PWMEN1 PWMCONObits PWMENO 1 1 POST SCALAR TIME BASE INTPUT CLOCK 1 1 TIME BASE IS FR I Fl E RUNNING MODI PWM TIME BASE IS ON ENABLE PWM 0 1 2 and 3 INDEPENDENT MODE FOR PWMO AND INDEPENDENT MODE FOR PWM2 AND PWM3 F 12 477 Final Report PTPERL kHz PTPERH LCD init WHILE LOO OxlF PWM 0 01 INITIALIZE while 1 BRK RK Ck Ck kk KK kk KK kk kk KK KK KK KK kk INCLINOMETER
34. SDA RDO TOCKI TSCKI RD3 SCK SCL 100 GP 1 0 RD1 SDO RD2 SDVSDA GP 02 GP 03 CD Data LED akelight ide PIC18F4331 C 3 477 Final Report 2008 Figure C 4 1 Sensors Functional Block B Inclinometer SCK Vdd MISO Vout MOSI ST GND CSB SCA61T R20 R25 Shunt Resistor OUT C4 477 Final Report 2008 Figure 4 2 Sensors Functional Block B Batt 2 IN Batt 2 IN Batt 1 IN Batt 1 IN Batt 4 IN Batt 4 IN Batt 3 IN Batt 3 IN o C 5 477 Final Report Fall 2008 Figure 5 Power Functional Block C Micro Power Supply U9 Vin Output SHDN 8 Sense C 6 477 Final Report Fall 2008 Figure C 6 Motor control Functional Block D 12V 011 b C9 C24 C7 C15 1u 5 180 33 R11 40K lt E1C2 lt Lo Gate R12 10K 0 7 477 Final Report 2008 Figure 7 User Interface Functional Block E 5V J20 Ride Mode Brakelight IN gt RIDE MODE BREAKLIGH 5V J19 LCD Data lt 0 426 GP l O 3 GP lO 2 GPlO1 gt Tach OUT gt Brakelight OUT gt GP VO TACH BREAKLIGHT 5 425 Throttle LCD BL IN Shunt IN Shunt IN C 8 477 Final Report 2008 Appendix D Layout Top and Bottom Copper Figure D 1 PCB Top Copper with Silkscreen LOO HE CE
35. TRISB2 TRISDbits TRISDO TRISDbits TRISD1 TRISDbits TRISD2 TRISDbits TRISD3 TRISDbits TRISD4 TRISDbits TRISD5 TRISDbits TRISD6 TRISDbits TRISD7 lt Output for coast feature Ne lt OF AO OOOO oO Ne PORTBbits RB1 1 PORTDbits RD1 1 Gate Driver Initially Enabled TIMER INTERRUPT INTIALIZATIONS 5 OpenTimerO0 OpenTimer2 PRESCALAR TO 1 1 TIMER INT ON amp TO 16BIT amp TO SOURCE INT amp TO PS 1 1 TIMER INT OFF amp T2 PS 1 1 amp T2 POST 1 1 SET PWM INTCONbits GIE INTCONbits TMROIF ANALOG TO DIGITAL CONVERSION INTIALIZATION OLD CONFIGURATION ADCONObits ACSCH 0 Single Channel Mod ADCONObits ACONV gt 0 Single shot mode ADCONObits ADON 1 Turns on AD ADCON1bits VCFG1 0 References are 5V amp OV ADCONIbits VCFGO 0 ADCON1bits FIFOEN 0 FIFO disabled ADCON2bits ADFM 1 Right justified results ADCON2bits ACQT3 0 ADCON2bits ACQT2 0 ADCON2bits ACQT1 1 4 TAD acquisition time select ADCON2bits ACQTO 0 ADCON2bits ADCS2 0 F 11 477 Final Report ADCON2bits ADCS1 1 ADCON2bits ADCSO 0 ANS ANS 0 0b11111111 ilbits ANS8 1 n 2008 AD 1 Fosc 32 set all inputs analog inputs EUSART INITIALIZATIO
36. Yx 0 putrsUSART r n MICRO BATTERY putrsUSART Micro Batt sprintf buf S2d ldV r n batt micro disp 100 batt micro disp 100 10 putsUSART buf DelaylOTCYx 0 s1 THROTTL putrsUSART Throttle 1 10 0 sprintf buf 3u throttle avg 102 10 putsUSART buf 77 MOTOR CONTROL RK RK KK kk kk KRK kk kk kk koc ke koc ke ke ke kk ek This is where the motor output is configured It works by reading the input from the throttle and then transposing it into a duty cycle which then determines the PWM output to the motor KCKCKCkCkCk Ck k Ck k kk kk kk kk kk kk kk kk kk ck k ck ck ck ck ckck KKR KKR ke x void motor void duty cycle throttle avg 0x0F lt lt 4 DELAY FOR 17 6 KHZ PWM FR dutyH duty cycle gt gt 8 amp OxOOFF dutyL duty cycle amp 0 00 F 9 EQU ENCY 0x25 Fall 2008 477 Final Report Fall 2008 PDCOH dutyH PDCOL dutyL 7 MAIN LOOP BRK RK Ck Ck KK KK KK KK Ck Ck Ck Ck ck KRK KKR This is the main pooling loop of the code It is where all the initializations are made with respect to the oscillator speed for the internal clock the input and output status of the port pins the ti
37. a Brushed PM DC motor is This means that the electromagnetic torque produced by the motor is directly related to the armature current by a motor constant This is the advantage of implementing current control and this was how the throttle data would have been interpreted in software However due to time constraints and other project issues a more simple voltage control scheme was used via PWM Motor Controller The motor will be controlled using a PWM signal from the micro The original plan of current control was abandoned due to time constraints However if it were to be implemented in the future a pin will be toggled on and off based on the control algorithm The frequency of this signal is not a discrete number but will vary depending on the load torque and throttle input Based on the throttle input the necessary current can be calculated This requested current would be given a certain hysteresis The actual current will then alternated in between the top and bottom hysteresis It is anticipated that the motor will switch between 4kHz and 10kHz However using a simple PWM signal ignores the current the motor is pulling and simply alters the applied voltage The signal is then be fed to an optical isolator and gate driver 26 This chip will protect the micro while amplifying the control signal to 12V the level required by the IGBT module 30 Originally the team anticipated using a full bridge 4 switches to control the motor
38. ability Interfacing with the rider via an LCD screen throttle control amp brake control is also very important The Moto eV must be safe for anyone with a moderate background of motorcycle experience to pick up and ride Battery level bike side to side lean angle and ride mode and throttle data will need to be displayed for the rider to monitor the bikes conditions 3 2 1 Computation Requirements The primary purpose for the microcontroller will be motor control This will be implemented through current control By monitoring and controlling the current feed it is easy to prevent the motor from attempting to draw excessive amounts of current This protects the batteries the switching circuit the associated linkages and the motor itself The motor control algorithm will monitor the requested throttle input and the real time current draw This data will be run through the software which then will subsequently cycle two discrete digital output pins that drive the two quadrant chopper By applying this method of control the system will operate within current limits imposed by the batteries IGBT and motor specifications This project 5 477 Final Report Fall 2008 requires a very fast ATD sampling frequency to monitor the current draw across the shunt resistor The current algorithm will require very accurate monitoring of the current draw at a high frequency This is due to the speed at which the current will be increasing during
39. ach battery weighs 19 416 which will give a total battery weight of a mere 77 6165 Their 4 92 x 6 54 x 6 89 form factor is extremely small and will offer a large variety of mounting options in the bike s frame These 10 477 Final Report 2008 batteries are sealed lead acid and not necessarily the ideal choice for this application There are several other battery chemistries which would offer better power to weight ratios However no technologies can beat the price of SLA batteries despite their high weight 6 The team also considered using 4 Panasonic LC X1228P SLA batteries 7 Each battery can provide 28Ah and weighs 24 34lbs for a total of 112Ah of power weighing 97108 These batteries have a nice small size at 6 49 x 4 92 x 7 07 which would have been easy to mount in the bike s frame The cost of these batteries was also very competitive at a mere 45 a piece ringing in at a total of 180 These batteries were less expensive offered a slightly higher capacity but each weighed 4 94lbs more than the LA 12V26Ah The extra 19 76lbs would have been worth the higher quality brand name Panasonic batteries and the extra 8Ah of capacity Ultimately cost won out over the other criteria of weight and capacity NPC Robotics sponsored the team with four 12V sealed lead acid batteries with a 350A max current draw for 10 seconds 100A continuous current draw and 18Ah of battery life The dimensions of the batteries
40. ad acid batteries and a DC brushed permanent magnet motor The motorcycle is designed primarily for city driving and will serve as a stylish alternative for gas combustion vehicles The motorcycle will offer a number of features aside from being a transportation vehicle an inclinometer will measure the lean angle of the rider a Ride Mode option which will set a maximum speed so that licensing and age restrictions will not apply to the bike in certain states and an LCD panel will display the amount of battery power left to power the bike the tilt angle of the user the throttle demand and the current ride mode Moto eV seems like an ideal candidate for patent infringement since the motorcycle has been in existence for so long and patented extensively When researching motorcycle scooter and bicycle devices to search for any potential infringements the existing patents must be analyzed with respect to the main components and functions of our project Since the Moto eV uses batteries to power DC motor and it 15 digitally controlled using a microcontroller and software there could be enough differences to show that the Moto eV has a substantially different function and performs in a substantially different way in order to avoid any potential liabilities 4 2 Results of Patent and Product Search Initially research regarding patent infringement was done with respect to the functions and methods of Moto eV as a whole the function being a mid
41. ain may end up being a blank polling loop For the functions outside of the main loop the loop is probably the most intense and important In this function will be called every time a timer interrupt takes place In the function first the input channel is designated then a while loop suspends until the conversion is completed When the conversion is completed the input value is saved to a value in an array which is then averaged This ensures that stray spikes in the current or throttle input don t result in the motor randomly kicking forward or losing power The throttle and shunt will be read every time adc loop is called but inside the function there will be an if loop with a counter which will decrement from ten to zero Every time zero is reached the battery meters and inclinometer will be read and the counter will be reset This will keep the priority of the throttle and current readings above the rest of the inputs while using only one timer interrupt The tim ISR function is extremely simple It only calls the ade loop function and clears the timer 1 interrupt flag The lcd disp fuction uses the putrsUSART putsUSUART and sprintf commands that come in the lt usart h gt header file in order to display characters on the crystal fontz LCD display which will be mounted on the motorcycle It has been used for debugging purposes thus far For the final display it will display the battery charge level for each batter
42. ancial prowess to manage licensing the patent the only option would be to not produce the motorcycle until the patent were to expire 4 5 Summary In summary the patents that most closely resemble the functions and methods of Moto eV are the motorcycle electric scooter and electric bicycle and the patents that resemble the motor control mechanism is the Electric Motor Controller and Microprocessor Motor Control Having Discreet Processing After reviewing the patents of those devices the Microprocessor Motor Control Having Discreet Processing would be a definitive issue with regards to patent infringement under the doctrine of equivalents Licensing would be the only possible option as this point but due to financial constraints the only viable option is to wait for the expiration of the patent at hand 19 477 Final Report 2008 5 0 Reliability and Safety Analysis 5 1 Introduction The Moto eV is designed to be an inexpensive and environmentally friendly form of transport for individuals living in condensed urban areas It can transport the rider a distance of up to 20 miles at 35 MPH on a single charge an can be recharged in under 6 hours The Moto eV will function just as any other motorcycle will with the expectation that it is fixed gear and fully electrical The main safety concern for this project is protecting the wellbeing of the rider and the motor control system by avoiding injury and damage from falling over T
43. as a protective shell for the electronics The PCB board which is estimated to be 72mm by 83mm and IGBT 93mm by 35mm by 30mm is placed underneath the tank The micro battery is mounted right next to the rear shock where the stock motorcycle originally mounted its 12V battery The LCD is mounted on the top of the tank The rider merely needs to look directly down to view critical data 7 4 Footprint Layout The microcontroller a PIC18F4431 is used in a 40 pin DIP package The inclinometer 5 chip is 10 48mm 11 31mm While the driver IR2184 chip is 9 9mm by 10 30mm This leads to a PCB board that is approximately 72mm by 83mm 7 5 Summary The Moto eV s main packaging constraints come from the fact we are using a prebuilt chassis Every component must fit within this existing frame The main constraints are the location of the motor and batteries After looking at other commercial products packaging the 3l 477 Final Report Fall 2008 initial plan of mounting the motor right in front of the singarm was confirmed The battery pack was designed to fit within the frame and we are utilizing the old tank to protect our sensitive electronics 32 477 Final Report 2008 8 0 Schematic Design Considerations 8 1 Introduction The Moto eV concept is a full scale electric motorcycle The Moto eV is engineered to be a commuting vehicle and thus will be equipped for a modest range of 25 miles wit
44. as designed to output 4 36V given a full 12V of battery charge The resistor values were chosen using commonly available parts as well as allowing for some headroom for slightly higher than 12V battery levels The 4 individual 12 SLA batteries input on pins RAS REO REI and RE2 The current monitoring circuit would of interfaced through 4 The PWM module is used for our main motor drive The motor is driven at a frequency of 7 8kHz This frequency is audible but when riding the bike there are several more prevalent noises Several general I O pins are used as well A LCD display selector switch and a ride mode selector are interfaced via RC4 and RD3 respectively The motor control signal will output on pin This pin was carefully selected to be both a digital I O and a PWM capable pin This leaves the team with a contingency plan of running the motor via PWM should the current control scheme fail Where in the end we did abandon current control and implement a voltage control Lastly pin TX will be used to output LCD data 36 477 Final Report 2008 Table 8 1 and Signal Table Signal Pin Title Pin Number Reset IMCLR 1 Throttle In ANO 2 Shunt AN2 4 Inclinometer In AN3 5 Battery 1 2 3 4 amp micro batt AN4 ANS AN6 AN7 AN8 6 7 8 9 10 Ride Mode Select In RC4 23 Power 5V Vdd 11 GND Vss 12 LCD Data Out TX 25 Motor Control Out RB1 PWMI1
45. assis The combustion engine and transmission will be replaced with an electric motor and a fixed gear final drive The Moto eV 15 engineered to be a commuting vehicle which provides a more environmentally friendly alternative to inner city driving 1 0 Project Overview and Block Diagram The idea for the Moto eV stemmed strongly from the groups mutual interest in electric motors All group members have taken ECE 321 and are all interested in using an electric motor to provide some sort of personal transportation Mike currently owns and rides a Honda VFR motorcycle and proposed the idea of designing an electric motorcycle The bike is powered by either a PM brushed DC being supplied with between 48 volts of the hardware is fitted into a 1986 Honda VF500F chassis and relevant user information is displayed through a LCD via serial interface The motorcycle is designed for short commutes to and from work or school Cruising speed is 35 miles per hour with effective range of 20 miles Mike s focus was on choosing and integrating the hardware peripherals as well as using his ee423 knowledge to assist Loren with motor control He also has extensive knowledge of the mechanical workings of motorcycles therefore he also was the lead mechanic in disassembly and maintenance Loren targeted motor control with hardware and in software as well as designing the layout for the PCB Arin undertook the responsibility lead programmer however every member of the t
46. ata via an analog signal from 0 5V or SPI Another plus to this option was that they only cost around 40 This was the team s best option given the constraints of operating voltage cost and output options Batteries There were several design constraints associated with the batteries but the most important was obviously voltage level The motor must operate between 48V and 72V To obtain this level the team used four 12V SLA batteries in series It was possible to implement more but due to budgetary reasons it was not considered The second constraint on the batteries was the amount of energy they can store With a motor that is capable of drawing over 200A in bursts the team needed plenty of battery capacity This capacity was a compromise with the third constraint which was physical size The frame had limited space and measured only 13 wide Also the batteries needed to be maintenance free rechargeable light and most importantly cheap The website batteryspace com offered the team a discount and their LA 12V26Ah model is particularly appealing The main motivation to use this particular model is its price point There are other more expensive models which would offer a greater riding range but they are out of reach due to the team s budget At 50 dollars apiece the LA model offers a nice balance The 26Ah capacity will give a total 104Ah of power This is obviously a compromise on range but should offer an increase in performance E
47. ator By introducing the presence of a microcontroller and controls that are digitally analyzed using software the substantial differences between Moto eV and the patented motorcycle seem great enough to avoid literal infringement with the help of a good lawyer The fact that Moto eV is meant for smaller distances and lower speeds than that which a fuel combustion engine is capable of could help to push the substantially different methods and functions of Moto eV with respect to the doctrine of equivalents Electric Scooter Factors supporting the substantially different methods and functions of Moto eV from an electric scooter would be based on the type of travelling and way that travelling is performed For example a scooter could be used for inner city travelling but could it be used to travel to work from home or any other particularly long distances Since Moto eV has a sitting user position a 48 volt power source and most probably a higher top speed it would be suitable for purposes beyond the scope of the electric scooter The fact that the motor is not literally attached to the rear wheel could also be twisted by the lawyer to show that it functions substantially differently from the motor mounted onto the rear wheel of an electric scooter Some licensing may be necessary to legally manage production of the Moto eV prototype even after considering any substantial differences with the point of view of the doctrine of equivalents but literal
48. cle to coast instead of shorting the motor upon deceleration The only problem we encountered was that the bootstrap capacitors were depleting during long durations of coasting Unfortunately I blew our A 5 477 Final Report 2008 last gate driver before we could fix this issue Luckily we were able to shoot our PSSC video before hand Loren my friend Mike and I spent a lot of time shooting and editing the video We started with over 10 minutes of film and edited it down to the final 2 minute run time Contributions of Loren Garby My fist contribution to the project involved contacting companies asking for sponsorship for the project Among the companies that I contacted were Alcoa National Power Chair NPC Elemental Design and Optima I also searched for used chassis on eBay and Craiglist I was able to secure 400 dollars in batteries from NPC Robotics and was offered a discount at Elemental Designs but to save on shipping we wound up purchasing our wire from another supplier in which we were already purchasing other components I then turned my attention to picking out our major components that we needed to be decided on for our design constraint analysis I researched microprocessors that were designed for motor control and found two PIC s that would meet our needs I then researched what type of chip we would need for our lean angle measurement Ioriginally looked at tilt sensors but soon d
49. df 12 Fairchild FMG2G150US60E IGBT Half Bridge Datasheet Online Document cited 5 February 2009 http www fairchildsemi com ds FM 2FFMG2G150US60E pdf 13 DiGiulio P C McDermott F E Salazar E Van Gorp W amp Weisman I 1990 Patent No 4897587 United States of America 14 Frederick T Budelman J 1986 Patent No 4622500 United States of America 15 Patmount S J 1996 Patent No 5775452 United States of America 51 477 Final Report Fall 2008 16 Saito 1986 Patent No 4709774 United States America 17 Whittaker R W 1998 Patent No 6155369 United States of America 18 Institute of Electrical and Electronics Engineers IEEE Code of Ethics Online Available http www ieee org portal pages iportals aboutus ethics code html Accessed Apr 7 2009 19 NHTSA Requirements for Manufacturers Motorcycle and Motor Driven Cycles Online Available http 204 68 195 250 cars rules maninfo mcpkg007 pdf Accessed Apr 8 2009 20 Teddy Bear Cops Recycling Program Online Available http www givecars com why recycle car html Accessed Apr 16 2009 21 Global Access to Recycling Markets Recycler s World Online Available http www recycle net tiredepot Accessed Apr 16 2009 22 Enertia Enertia Electric Motorcycle Online Document cited 6 February 2009 http www enertiabike com
50. e noise therefore added capacitors and resistors to the circuit I worked on adding the heat sink and fan under the electronic mounting plate 1 477 Final Report Fall 2008 A 2 Contributions of Arin Chakraverty For the first two weeks my contribution to the team was the development of the team webpage I developed the main layout of the website by configuring the theme buttons and header links I also set up all the individual notebooks for the rest of the team to just start updating them During the second week I finalized a working format for the website although it could still use some style point The third week consisted almost entirely of the component search process I didn t understand a lot of the motor control mechanism and components involved so I let Loren and Mike take the lead for that I would still help in anyway I could though by looking up products and components and learning about the datasheets and systems to try and get lower prices that met our requirements I then devoted my time to setting up a complete schedule with all of the group members to help arrange meeting times In the next few weeks my major contribution consisted of making the CAD models of the chassis and the mounting scenario I had experience from my summer internship last year using AutoCAD 2008 in 2D So it was quite a bit of hard work and self teaching to extrapolate my computer graphic skills into creating a 3D model for this project
51. e the material will be disposed of properly For the rest of the frame it could be recycled either in pieces or as a whole 21 For the disposal of the tires users will be advised to find proper recycling facilites 27 477 Final Report 2008 6 4 Summary The ethical and environmental impact of the Moto eV has been carefully considered The main ethical concern is the safety of the rider therefore many test will be implemented prior to the production of the bike Also there will be warnings located on the bike with more information on what the labels mean and how to ride the motorcycle located in the manual With respect to the environmental impact the major concern was the PCB LCD and the proper disposal of the batteries 28 477 Final Report Fall 2008 7 0 Packaging Design Considerations 7 1 Introduction As an electric motorcycle the Moto eV requires that batteries and motor must fit within the frame of the motorcycle The chassis that is used for this product is a 1986 Honda VF500F The main constraint is that the motor must be mounted directly in front of the swingarm The PCB switching circuitry LCD and associated hardware fit underneath the existing tank 7 2 Commercial Product Packaging With the current energy crisis people are doing anything to try and limit the amount of gas being used Consequently the demand for electric vehicles has increase Some commercial products that are similar to
52. e to isolate sensitive signals from noisy ones and to keep all trace lengths to the micro down to a minimum This also reduces EMI and parasitic inductances that can cause significant degradation in the SNR Large traces are used for the power and ground due to the large current draw from the gate driver and LCD backlight Careful planning of part placement and port usage makes the PCB layout process run much smoother and take considerably less time 41 477 Final Report 2008 10 0 Software Design Considerations 10 1 Introduction The Moto eV concept is a full scale electric motorcycle The Moto eV motorcycle is engineered to be a commuting vehicle and thus will be equipped for a modest range of 25 miles with a top speed around 40 mph The motorcycle will house a MARS 0709 brushed permanent magnet DC motor which will be powered by four twelve volt sealed lead acid batteries The main software considerations involve powering the motor with respect to the feedback received from the peripherals on the bike to ensure that everything is working reliably and safely The peripherals on our bike are easier to summarize when looking at their real time priority levels The most important component will be the shunt resistor circuit to determine the current draw of the motor closely following is the throttle input then come the inclinometer circuit battery level monitoring circuits brake lights and LCD display preference inputs t
53. eam will contribute in this area Janell took charge of packaging all of our components into the motorcycle frame The entire team will be committed to the testing and debugging as well as the final paint job 477 Final Report Fall 2008 Table 1 1 Initial Cost Estimate Part Quantity Price Cost PM Brushed DC Motor 500 500 12V SLA Batteries 4 6 100 600 VF500F Chassis 1 100 100 Metal and Fasteners N A 150 150 Sprockets 2 75 150 LCD Screen 1 75 75 Tilt Sensor 1 15 15 1 590 Figure 1 1 Block Diagram 5V Regulator ights 48 V Brushed Battery DC Motor Monitor LCD Display 2 ee PIC18F4431 Gate RA4 RAS RAG RAT 4 Monitor PGM PGC IMCLR PWR GRD 20V PWR GRD TX PWMO Boost Inclinometer 20X4LCD 477 Final Report 2008 Table 1 2 Division Labor Design Component Homework Professional Component Homework 4 Packaging Design and Specs Janell 3 Design Constraint Analysis Parts List Mike 5 Hardware Narrative and Prelim Schematic Mike 10 Patent Liability Analysis Arin 6 PCB Narrative and Prelim Layout Loren 11 Reliability and Safety Analysis Loren 9 Software Design Narrative Arin 12 Social Political Environmental Analysis Janell 477 Final Report 2008 2 0 Team Success Criteria and Fulfillment An ability to
54. f bridge as well as the optical isolator gate driver chip The FMG2G150US60E IGBT half bridge can handle up to 600V and 150A continuous across the collector and emitter 12 This worked perfectly for the power needs of the Mars motor 3 4 Summary The Moto eV project uses a 1986 Honda VF500F chassis powered by a Mars Brushed PM DC motor This motor works well for this project due to its weight and power output The motor runs off of 48V provided from four 12V SLA batteries in series While these batteries are heavier than alternate options they offer the best price to performance weight amp capacity ratio System control is implemented with a PIC18F4431 This micro provides the necessary high speed ATD PWM and general I O pins A current control algorithm is used to switch an external IGBT module which in turn will power the motor Relevant user information is provided on a character based 20x4 Crystalfontz LCD This screen is easily interfaced with using serial communication and offers the screen real estate required for the data This data consists of battery charge current draw throttle demand amp lean angle values The lean angle will be provided by VTI 5 single axis inclinometer a small surface mount chips which provides 90 degrees range of measurement 13 477 Final Report 2008 4 0 Patent Liability Analysis 4 1 Introduction The Moto eV is an electric motorcycle which is powered by sealed le
55. fe of the product manufacturing normal use and disposal recycling The main concern during the manufacturing stage is the pollution that occurs during the fabrication of the printed circuit board PCB from the chemicals and natural resources that are needed in the fabrication process Therefore all the chemicals and materials must be separated and taken care of respectively With this taken into consideration Moto eV would look into the production and waste procedures to determine a producer Use of the Moto eV is more environmentally safe than most other motorcycles due to the fact that the Moto eV does not have harmful emissions The batteries could become an issue if they were to become damaged for instance if the bike was in a collision Thus sealed lead acid batteries were selected to prevent of any chemicals from leaking into the environment Also during normal production tires will need to be changed periodically and the old ones will need to be discarded In order to be more environmentally safe the manually will provide information for the recycling of the tires 20 At the end of the product s life the product should be taken apart so that different components can be disposed of or recycled as needed The batteries should be brought to any automotive store so that they can be recycled this information will be in the manual As for the PCB and LCD there will be information in the manual so that they can be sent back to the company wher
56. g Constraints The main packaging constraints were the size of the motorcycle frame There is plenty of room inside the tank for the large circuit board switching circuitry LCD and associated hardware However the batteries and motor are more restricted The motor can only be mounted directly in front of the swing arm and it should not have a depth that is wider than the bike s frame The batteries are mounted inside of a battery cage This cage is mounted in front of the motor and behind the front wheel in whatever space 15 left inside the frame once the motor is mounted The cage is also removable in order to allow access to the individual batteries The dimensions of the batteries are compact while still providing a respectable amount of power 3 2 7 Cost Constraints Cost constraints are 305 per team member for a total of 1 219 58 dollars This is out of pocket money and does not consider any donations made The team acquired a LCD module from Crystalfontz a potentiometer throttle from Magura 12V sealed lead acid batteries from 477 Final Report 2008 Robotics connectors from Molex and fuses fuse block and master switch from Blue Sea The cost to the team was 100 for the rolling chassis and 350 for the motor plus additional hardware costs 3 3 Component Selection Rationale Chassis The donor chassis being used for this project is 1986 Honda VF500F This was chosen for its small size frame de
57. h a top speed around 35 mph The design requires precise sensor input to the microcontroller as well as medium to high frequency switching motor drive output We are using seven analog inputs to the microcontroller and this data cannot be corrupted from the noise generated by the switching circuitry and the motor 8 2 Theory of Operation Microcontroller The PIC18F4431 microcontroller interfaces with all of the major components on the bike 2 The main function of this component is to collect relevant sensor and user input data then process this data to modify the motor control and user display The microcontroller will capture inputs from the throttle an inclinometer and a battery monitoring circuit The throttle information is used for motor control while the battery monitoring and inclinometer will be used for the user display Power Supply The Moto eV will have two completely separate power systems The main 12V system will run off of a single sealed 12V battery mounted inside the tank The components on the pcb that will run at the full 12V are the gate driver the heatsink fan and the differential amplifiers The gate driver will take the logic level 0 to 5V from the micro and then optically isolate and amplify that signal The 12V micro battery will be stepped down to 5V through a linear regulator to power the other circuitry on the pcb 34 While a linear regulator is not the most efficient means of converting a DC signal to a lowe
58. have been made in order to complete the following analysis Such as all components are operating at their respective maximum temperatures Also the system will be ground mobile with commercially manufactured parts and has been in production for over two years The tables below are used to derive the failure rates and MTTF using these assumptions and information taken from the component datasheets Table 5 1 LT 1529 Linear Voltage Regulator Parameter Description Value Comments Die Complexity 02 Linear MOS 101 300 transistors Temperature Factor 58 Linear MOS Max Temp of 125 C Package Failure Rate 0016 4 pins Nonhermetic DIP TE Environmental Factor 4 Ground Mobile Quality Factor 10 Commercial Learning Factor 1 In Production for over 2 years Failures 10 hours 11 664 85 733 88 hours 9 787 years 21 477 Final Report 2008 Parameter C TQ TL Parameter C 5 2 8 4331 Description Value Comments Die Complexity 28 16 bit CMOS Temperature Factor 3 1 CMOS Max Temp of 125 Package Failure Rate 019 40 pins Nonhermetic DIP Environmental Factor 4 Ground Mobile Quality Factor 10 Commercial Learning Factor 1 In Production over 2 years Failures 10 hours 9 44 105932 20 hours 12 093 years Table 5 3 LM2733 Boost Description Value Comments Die Complexity 02 Linear
59. he least important real time component is the ride mode input The main control of the motorcycle will come from the user turning the throttle and expecting the motor to respond accordingly The current draw and throttle input also happen to have the most volatility over time Thus the main purpose of the microprocessor s software will be to process a motor control algorithm based on these two components The inclinometer battery monitors brake lights and lcd monitor will also be varying with time but more predictably and with less of an impact on the control of the bike They will be incorporated into the software when reaching extreme levels When the batteries are becoming too drained or the motorcycle is at an excessively acute angle the motor control algorithm may be affected The ride mode can only be selected when the bike is at a stall and will have priority only when the bike shows no speed 10 2 Software Design Considerations Memory Mapping The microprocessor chosen for our project is the Microchip PIC18F4331 It has a 21 bit program counter which addresses the 2 mega bytes of program memory available along with 8 kilo bytes of flash memory capable of storing up to 4 096 single word instructions The user 42 477 Final Report Fall 2008 space memory program memory starts with the RESET at 000 000h memory address Then the high priority interrupt and low priority interrupt vectors are located at 000 008h and 000 018h
60. he Moto eV can only go so far in protecting the rider from danger ultimately it is still the rider s responsibility to be a safe and smart driver A safety feature that has been implemented on the bike is a mechanical kill switch This physically breaks the circuit that sends power to the motor in case there is a failure with any part of the motor control circuitry and the motor ramps up without any user input With this implemented if the user does lose control over the motor speed he can simply turn a key and shut down the motor To be a successful and commercial product the Moto eV also needs to be reliable The schematic has been broken down into five functional blocks and components from each will be analyzed individually A few of the most critical components that will be represented in this report include the LT 1529 Linear Voltage Regulators 34 the PIC18F4331 microcontroller 2 the CM300DY 24H IGBT 30 and the LM2733 Boost converter 35 The failure rate and mean time to failure MTTF are included in the tables below for each of the previously mentioned components 5 2 Reliability Analysis The components mentioned above have a high risk associated with them if they fail They have been analyzed for reliability and the results can be seen in the tables below The LDO boost IGBT s are the components in with the highest probability of failure due to over heating If the LDO failed it would cause the entire system to stop working
61. he functional block The functional blocks are organized in the following manner A Microcontroller B Sensors C Power D Motor Control 23 477 Final Report Fall 2008 E User Interface Each failure is assigned a failure criticality level corresponding to its severity The following table explains how the levels are broken down Table 2 1 Criticality levels Criticality Failure effect Maximum Probability Failure that causes system instability High Ap 2 10 Possible damage to user and or system Requires replacement of minor component 8 Medium 10 lt A 10 Causes undesirable behavior LCD malfunction incorrect battery level 5 Low lt 10 No damage to device 54 Summary The components that were analyzed are very important because failures in those particular functional blocks have high criticality MTTF is a good estimate of the lifetime of these components and by operating them in a reasonable range they should be more than sufficient for use in the Moto eV With regards to the FMEC analysis the most critical failures occur in Sections D amp E which contain the motor control and user interface Failure in any of these two regions can cause damage to the device or the user Precautions have been taken to prevent such accidents but unforeseen complications can arise during operation that will have to be corrected before the Moto eV is ready for commercial productio
62. icult part of this PSSC was tuning in each individual differential amplifier to display the correct voltage to the LCD The final PSSC to be completed was PSSC 3 This dampens the throttle input and limits the maximum speed of the bike to allow for a novice rider to feel comfortable and safe while riding 477 Final Report 2008 3 0 Constraint Analysis and Component Selection 3 1 Introduction The Moto eV concept is a full scale electric motorcycle The Moto eV is engineered to be a commuting vehicle and thus will be equipped for a modest range of 25 miles with a top speed around 35 mph The main design constraints stem from the size and weight of the 1986 Honda VF500F chassis The combustion engine and transmission will be replaced with a brushed PM DC motor and a fixed gear final drive 3 2 Design Constraint Analysis Given the target consumer of the Moto eV is the short distance commuter the main constraints are focused on obtaining a certain top speed and run time This will require a balance of power and weight in the batteries and the motor Also an adequately powerful motor and a sufficient number of batteries each with an ample amount of stored energy will be required AII of this hardware will have to be light to reach the target performance Interfacing with such large power components will be extremely challenging Some parts will be required to handle extremely large amounts of current while maintaining long term reli
63. ing After Loren and I breadboarded the circuit and used a desk power supply to run it we discovered that the issue lay with our 5V regulator After we reviewed and modified our 5V LDO circuit the boost worked perfectly Another issue was with the differential amplifier footprints I installed surfboards for each differential amplifier Loren and I then finished installing all of the connectors and components 4 477 Final Report 2008 I took some time to test a couple of the different gate drivers that I picked out Theoretically the IR2184 was superior to the IR2302 I set up a test bench and used high power 3 2 ohm resistors as my test load I played around with different gate resistances and obtained several plots from the scope which I posted to the webpage This analysis helped me to decide which gate driver to use in our final implementation After it was determined that the hardware was pretty much finished I started on software Unfortunately we got a late start on the software so I started from scratch I read through the user manual and tutorials My first piece of software was simply getting the micro initialized correctly and having the ATD working After I got the ATD working I then started on the LCD software I researched the built in USART functions and eventually go the LCD to display correctly Arin and I wrote a current control algorithm but unfortunately it fried our gate driver We decided that it was too late
64. iscovered that these act more as a switch once a certain angle of incline is achieved I then found inclinometers which output a certain voltage based on the angle of inclination This matched perfectly with what we wanted for our bike I then found a large discrete shunt resistor that matched our power needs and had a low enough resistance Then I researched IGBT s and tried to find a high enough current rating that wasn t too expensive We decided that an IGBT module would be the best option for us due to the easy integration If we didn t find a module to use we would need multiple discrete IGBT s in parallel on a PCB and we would have to worry about creating traces large enough to handle 300 amps Mike designed most of the schematic but towards the end I helped with which pins should go to which connector After our first formal design review I designed the circuit for the differential amplifiers for our battery monitoring as well as the 20V boost circuit Throughout the semester up to this point Mike and I spent a considerable amount of time discussing with ourselves and professor Wasynczuk the different methods of motor control and how to implement them Soon after the schematic was finalize I turned my attention to the PCB Layout I looked over the footprint book that we have in lab and learned the notation that OrCad A 6 477 Final Report Fall 2008 uses for their footprints I then created the netlist for our schematic and imp
65. ks accomplished at different frequencies based on timers which define intervals in the microprocessor The remainder of the patent goes into great detail about the types of sensors being used for determining EMF calculating speeds and managing communication devices There are a number of similarities between the function and way that Moto eV accomplishes motor control and the way the Microprocessor Motor Controller Having Discreet Processing does things The use of different intervals of time to accomplish tasks at different intervals would probably be extrapolated for the purpose of maintaining a sense of priority although it wasn t specifically documented in that fashion The wording was quite ingenious in this patent because it essentially makes any motor controller that uses interrupt service routines viable for infringement This is a definitive candidate for patent infringement under the doctrine of equivalents for having substantially the same function in a substantially same method 4 4 Action Recommended For the first three of the previously mentioned patents there does not seem to be any highly intimidating potential for infringement The motorcycle and electric bicycle patents both 18 477 Final Report Fall 2008 used exclusively mechanical systems This is a huge factor of persuasion under the doctrine of equivalents in support of Moto eV When comparing the capabilities and functions of a digital system to those of a mecha
66. low elements with less real time needs to be processed and read only in multiples of the higher priority processes The single timer interrupt service routine will call functions for the ADC and increment counters The rest of the grunt work takes place in the main loop In the main loop majority of the code are simply initializations with regards to settings certain pins and ports as outputs or inputs and setting prescaler postscaler and configuration bits for the more complex operations like the PWM ADC and SCI modules The rationale for this new system of organization was based on its simplicity It became apparent that the needs of Moto eV with respect to the capabilities of the PIC18F4331 micro were nothing too extravagant Reading sensor inputs configuring their values quickly and then updating the LCD display output and motor power output are the operations of the microprocessor in a nutshell So a simple single ISR polling loop should do the job effectively and accurately 10 3 Software Design Narrative The software design builds off an interrupt service routine powered by the timer module The timer sets an interrupt at a 1 1 ratio to the clock speed of the internal oscillator 8 MHz The main loop will consist primarily of initializations for all the different peripheral modules The functions and loops outside of the main loop are the loop tim ISR led disp and motor These functions will be called by the timer in
67. ments The input output I O requirements the previous section dictate the use of a micro with at least five 10 bit analog to digital inputs three digital inputs one channel of 10 bit PWM and SCI UART functionality Additional general I O pins will be required for the possibility of future peripherals 477 Final Report 2008 3 2 4 Off Chip Peripheral Requirements The off chip peripherals that are interfaced with the microprocessor are the built in serial communication chip on the LCD the single axis inclinometer chip and the gate driver chip 32 5 Power Constraints The Moto eV is powered from around 72Ah of battery power Despite this large well of energy the drive circuitry must remain efficient in order to leave as much power as possible available to the motor A 5V supply voltage will provide an ample ATD resolution while not consuming too much power The abilities of the switching circuit will be dictated by the motor s power requirements A robust switching circuit using an insulated gate bipolar transistor IGBT is required for this application To dissipate the heat generated from switching a long heatsink and fan is mounted below the IGBT 30 The switching circuit and batteries will need to be able to supply short burst of high currents up to 200 amps with capacitor assistance The batteries also must provide at least 48V of power while being rechargeable light and compact 3 2 6 Packagin
68. mer intializations and their scalings the initializations of the pins and how they are sampled and referenced EUSART initializations for the LCD display output settings and finally the PWM settings for the control of the motor output and to set the PWM frequency to maximize motor output and minimize the noise produced by the motor The nested while 1 loop in the main function includes the inclinometer readings and algorithm to display the degrees appropriately It also has a lcd display monitoring set up to check which lcd display page should be output EK kk kk kk kk kk kk k k kk ck ck ckck ck ck ckck ck ck kc ke ke x void main void INTERNAL OSCILLATOR PRESCALAR OSCCONbits IRCF2 1 OSCCONbits IRCF1 1 8MHz OSCCONbits IRCFO 1 IRCF2 IRCFO 111 8 MHz 110 4 MHz 101 2 MHz 100 1 MHz 011 500 kHz 010 250 kHz 001 125 kHz 000 31 kHz PORT STATUS TRISA OxFF Port A set as input F 10 477 Final Report Fall 2008 TRISEbits TRIS TRISEbits TRISI TRISEbits TRIS Port set as input AN6 Port 1 set as input Port E2 set as input AN8 Fl pH Ne TRISCbits TRISC5 TRISCbits TRISC4 gt LCD Display toggle input Ride Mode toggle input TRISBbits TRISB1 TRISBbits
69. microchip com downloads en DeviceDoc 39616C pdf 3 Microchip dsPIC30F3011 Datasheet Online Document cited 5 February 2009 http ww1 microchip com downloads en DeviceDoc 70141e pdf 4 Reiker H4 Inclinometer Datasheet Online Document cited 5 February 2009 http www riekerinc com E Inclinometers H4 20PDFs H4 20SeriesW 5 VTI Technologies SCA61T Inclinometer Datasheet Online Document cited 5 February 2009 http www vti fi midcom serveattachmentguid 53b766f2850a127b88947edbflde536f SCA61T_inclinometer_datasheet_8261900A pdf 6 D Naunin Electric Vehicles Technical University of Berlin pp 16 17 1996 7 Panasonic LC X1228P Datasheet Online Document cited 5 February 2009 http www panasonic com industrial battery oem images pdf Panasonic_VRLA_LC X1228P_LC X1228AP pdf 8 Chan and Chau An Overview of Power Electronics in Electric Vehicles University of Hong Kong pp 6 8 1997 9 Lemco Ltd LEM 200 D127 Datasheet Online Document cited 5 February 2009 http www l1mcltd net uploads files 130 table pdf 10 Mars Motors LCC Mars ME0709 Datasheet Online Document cited 5 February 2009 http lib store yahoo net lib yhst 57437235823410 ME0709Data 11 Crystalfontz CFA632 NFA KS LCD Datasheet Online Document cited 5 February 2009 http www crystalfontz com products 632 datasheets 34 CFA 632_v2 0 p
70. n Overall Moto eV is a safe and reliable product 24 477 Final Report 2008 6 0 Ethical and Environmental Impact Analysis 6 1 Introduction The Moto eV is a full scale electric motorcycle The Moto eV is engineered to be a commuting vehicle and thus will be equipped for a modest range of 25 miles with a top speed around 40 mph The bike will be powered by a bank of four 12V SLA batteries connected in series to provide 48V to the motor The microcontroller will run off of a single sealed 12V lantern battery mounted inside the tank Just like any other product that is going to be marketed there are ethical and environmental issues that need to be taken into consideration prior the release of the product As a mode of transportation the main ethical concern would be the safety of the rider Therefore where to place warning labels and the testing of the product in many situations was taken into consideration In terms of environmental issues topics to consider are pollution and waste that may take place during the three phases of the product s life manufacturing normal use and recycling disposal 6 2 Ethical Impact Analysis Since there are many ethical considerations that needed to be taken into account prior to the production of the Moto eV the Institute of Electrical and Electronics Engineers IEEE Code of Ethics 18 was used as a reference The rider s safety is at utmost importance since the Moto eV will be con
71. n Synchronous Serial Port SSP SPI EUSART DC RS 232 UART Operating Voltage V 5 0 5 0 Instruction Set Size T5 83 Pin Count 40 40 44 Internal Oscillator YES YES These two chips are very similar and both would have most likely met the project needs When deciding which chip to choose the exact frequency at which the current needed to be monitored was not known This frequency would have been dependent on the motor and the team needed to get more concrete data on the motor However it was unlikely that a sampling frequency greater than 200ksps was going to be required Therefore the team decided to use the PIC18F4431 This processor offered all of the peripherals required and also provided enough extra pins for any design expansions that took place 477 Final Report 2008 Inclinometer The first contender in the inclinometer selection was the Rieker H4 4 This inclinometer is designed for rugged applications on cranes agricultural equipment and other industrial applications It offers a range of 70 degrees and outputs an analog voltage of 0 5V The only drawback was the cost which is unknown but anticipated to be in excess of 100 The other sensor option was the VTI single axis SCA61T FA1HIG digikey part 551 1005 1 ND 5 This small surface mount device has a measuring range of 90 degrees and includes internal temperature measurements and compensations It operates on 5V and outputs d
72. nclinometers are in general very sensitive to temperature fluctuations This sensor will interface to the micro via an ATD pin and then calculations in software provide accurate angle measurements Micro battery monitoring is implemented using a simple voltage divider connected directly to the battery and input through an ATD pin It will be important to use very high value resistors as to not draw too much current away from powering the motor While there are more elegant and efficient means of implementing a charge monitoring circuit this alternative provides the simplest solution Also since the micro battery is of the lead acid chemistry the battery level drop off should be quite linear This linearity provides an accurate measurement using a voltage divider However the main 48V battery bank is monitored by differential amplifiers Each of the four 12V SLA batteries is read and displayed via the LCD This gives the user early warning if one of the batteries is starting to go bad The main motor control input is the throttle The team has obtained sponsorship of a 0 5 potentiometer throttle from Magura This is a complete unit which can mount directly in place of a normal mechanical motorcycle throttle It will interface with the micro controller via pin 100 open throttle will correspond to about 00 of resistance This input will then 34 477 Final Report Fall 2008 be directly related to current The torque equation for
73. nd low priority interrupt routine where everything was being tested and confirmed using the development kit and flashing its LEDS It was also around this time that the software design and patent liabilities homework assignments started to consume much of my tie The end of the semester consisted of Mike Loren and I working hard on the software aspects of the project I was the expert when it came to setting up the timers and their scalars configuring the PWM frequency and scaling the duty cycle respectively and then finally setting up the ATD input channels appropriately I give props to Mike and Loren to jumping into the software side of things at this point because it was all we had left to work on Some troubles surfaced as we worked on the motorcycle and got it working during the last couple weeks It seems to have been working fine and then certain diodes chips and the IGBT were getting burned out for unknown reasons After using up the last replacements and backups we just had to call the project where it was It was successful from a grading aspect The last push and effort were with respect to finishing up the paperwork and presentations for finals week for which I did a great deal of editing and writing A 3 Contributions of Mike Stuckenschneider My first contribution to the project was finding our chassis I spent quite a bit of time of Christmas break scouring Craigslist and ebay looking for a rolling chassis Once I found a
74. nical system vast differences can be found in how Moto eV functions and what its purposes are The main gist of the substantially different functions lies in the exclusive purpose of travelling moderate distances like the kind of travelling that takes place regularly in high traffic metropolis areas It would be unlikely that the motorcycle or electric scooter could find the legal prowess to show that Moto eV is guilty of patent infringement The electric bicycle is more similar to Moto eV in its purpose than the motorcycle or scooter but once again the mechanical systems of the clutch and gear switching components have caused great differences between Moto eV and the electric bicycle Thus the action recommended would be to highly emphasize the differences between mechanical systems in the current patents and the digital systems being implemented in Moto eV In the case that patent infringement does become a real issue and digital systems are not capable of showing their substantial differences in how the devices work The functions of Moto eV should be brought up to explain that the purpose of Moto eV may overlap with that of a motorcycle scooter or bicycle but mostly entertains its own category of city travelling at moderate distances Ultimately all is in vain though The Microprocessor Motor Control Having Discreet Processing would definitely be a case of patent infringement under the doctrine of equivalents Since Moto eV doesn t have the fin
75. orted it into Layout After it was all said and done I made six iterations to the layout created 16 custom footprints and spent a total of 40 hours During that time I made numerous changes to the schematic so to avoid adding vias and to allow wires to run straight into their respective connectors Over spring break I spent approximately 16 hours working on fiber glassing the tank and fitting the LCD I documented this expensively in my notebook but since this was more done for aesthetic reasons I will not go into depth in this paper After spring break Mike and I spent two weeks populating our PCB Most of this time was spent troubleshooting why our 20V boost converter was not working Our 5v LDO worked right away but when we added the boost converter neither worked It turned out that the problem was with our LDO after all We used a sensing circuit that was in the application notes which would not work for our purposes We removed two resistors from our circuit and both power rails worked perfectly The only other problem we had with the population was with the differential amplifier footprints The datasheet did not have technical drawings of the differential amplifiers and I did not realize that SOIC packages were of universal size and lead space After the PCB was populated I started working on integrating everything onto the bike I trimmed the electronics plate to fit better into the frame and drilled all of the mounting and through holes for the
76. r DC signal this method was chosen for its simplicity When compared to the power being used by the rest of the system in the bike the small amount of power lost in this component is of little concern This 5V will power the microcontroller LCD inclinometer amp system lighting 33 477 Final Report 2008 The other power system used inside the bike will be completely dedicated to the motors A bank of four 12V SLA batteries connected in series will be used to provide 48V to the motor This system will need to be separate from the microcontroller 12V system but issues will arise from having two supplies and two separate grounds This issue was solved by using a common chassis ground It is necessary to isolate the micro system because of the huge amounts of power the motor requires The motor can pull 114A continuously and peak draw can exceed 300A We used 4 gauge wire to connect the batteries IGBT amp motor This large diameter wire is necessary to handle the large amount of current our drive system uses Sensors amp Inputs A single axis inclinometer is used to monitor bike lean angles 25 This chip is oriented on the pcb at a slight anlge to the horizon with pin one facing the front left of the bike such that it will record side to side changes in angle The inclinometer has an internal temperature sensor and it adjust its output in real time using the collected temperature data This is very beneficial because i
77. r due to it only being a single axis and that axis must be perpendicular to the angle of incline 25 39 477 Final Report 2008 Thirdly the digital I O is isolated to again avoid noise on the signal This is not nearly as important as the analog I O because we can accommodate a larger variation in the digital signal and no key control or device monitoring will be conducted on these lines Finally the gate driver is as far as possible from the analog I O This is due to the high current draw and fast switching frequency that the gate driver must achieve 26 These are the main factors that contribute to EMI and because of this a ground pour underneath the IC would be favorable The trace leading to the output header is approximately 50 mils to accommodate the current draw which is expected to be in the 300mA range There is plenty of mounting space for the board so size is not really an issue An initial estimates of 6x6 inches was chosen and the final board dimensions measured in at 5 735 x 4 975 This provides us with enough space to isolate our sensitive components and to keep our trace lengths short enough to avoid parasitic inductances 9 3 PCB Layout Design Considerations Microcontroller The microcontroller is a PIC18F4431 and we have chosen a DIP package due to its simple installation and port pin arrangement 2 The micro is placed vertically in the middle of the board to allow easy access to the port pins f
78. rent can be measured and current control can be implemented It was decided that version one would use a single two quadrant chopper IGBT module These were purchased used due to their high price and simplicity of integration The next iteration will use discrete IGBT s This is much more cost efficient and allows for adjustable current handling and easy replacement of broken parts This would be harder to interface with but the benefits outweigh the costs 49 477 Final Report 2008 12 0 Summary and Conclusions This semester proved to be extremely challenging yet at the same time very rewarding This was the largest project that the team has undertaken from start to finish Many of the requirements of this project were new to the team including ordering parts designing a pcb layout and contacting companies for sponsorship By the end of the semester we had demonstrated all five of our PSSCs and had an end product that is actually usable While the semester has ended the Moto eV is in its infancy of development The team learned a great deal about teamwork problem solving meeting deadlines motor control and of course embedded programming 50 477 Final Report Fall 2008 13 0 References 1 Chan and Chau Power Electronics Challenges in Electric Vehicles University of Hong Kong pp 703 1993 2 Microchip PIC18F4431 Datasheet Online Document cited 5 February 2009 http ww1
79. respectively The addresses from 000 019h to 001 FFFh are allocated for on chip flash Lastly the addresses from 002 000h to FFFh are categorized as Unused Read 075 Above all the program memory is the 32 bit stack memory As shown in the figure below the memory location for the 31 word deep stack is located in the 32 bytes before the 000 0000h RESET location Figure 10 1 Memory Map on PIC18F4431 CALL RCALL RETURN RETFIE RETLW Reset Vector LSb PO High Priority Interrupt Vector LSb 5 Low Priority Interrupt Vector LSb On Chip Flash Program Memory gt 3 23 a 1FFFFFh For programming the microprocessor Microchips MPLAB C18 compiler will be used in conjunction with the ICD2 programmer and development kit One of the great benefits of using this development kit is how the application code is optimally organized when the code is built on 43 477 Final Report 2008 Thus the locations for static data variables stack and code are automatically placed in their respective memory locations by the compiler of the start up code and initializations are also taken care of by the compiler software Peripherals The peripherals of the PIC18F4331 that will be used for monitoring and controlling the motorcycle are the analog to digital conversion ADC module the timer module capture compare CPP module serial communication interface SCI and the pulse width modulation PWM
80. roller and another set are connected in series to the input terminals to the controller By using a pulse train at a frequency much higher than the mechanical resonant frequency the error signal modulates the speed of the motor by changing the duty cycle of the pulse train This seems to be extremely similar to the use of a PWM system to set the motor output to specifically preset duty cycles Microprocessor Motor Controller Having Discreet Processing Filing date Jan 30 1990 This patent is worded in a manner that makes it sound like it is used for large scale multiple device motor control mechanisms According to claim 1 the motor control is accomplished using a microprocessor that uses its outputs to signal outputting power and uses its inputs to read a variety of sensors providing feedback information to help control the motor apparatus The second main point in this patent essentially summarizes the principle of an interrupt service routine There are different motor control tasks accomplished at different frequencies based on timers which define intervals in the microprocessor The remainder of the 16 477 Final Report 2008 patent goes into great detail about the types of sensors being used for determining calculating speeds and managing communication devices 4 3 Analysis of Patent Liability Motorcycle Patent The motorcycle patent is a highly mechanical system distinguished by its design around the radi
81. rom each IC The port pins for each device were chosen to help facilitate the partitioning of the board into its four quadrants The microcontroller itself will not source much current so a 50 mil trace is more than adaquate The power and ground traces run up the side of the micro and branch out to supply power to the micro and individual IC s Several bypass capacitors are placed underneath the micro to facilitate any instantaneous power needs No external oscillator is needed with this microcontroller since we are not doing anything that requires very precise timing The internal clock will be more than accurate 94 Layout Design Considerations Power Supply The 12V source is sent through the LT1529 to produce the 5V rail The maximum current draw will be 2 Amps therefore the power and ground traces are 100 mils The current is largely dependent on how bright our LCD backlight is The LCD backlight at full brightness will pull 380 mA The 5V rail also supplies the LM2733 which boosts the voltage to 20V This is only to power the differential amplifiers and will not draw much current The power traces 40 477 Final Report 2008 from the LM2733 will are 30 mils Bulk capacitors placed close to where the sources enter the board and decoupling capacitors are placed under the all of the IC s 9 5 Summary In conclusion the PCB is partitioned into four quadrants with the microcontroller at the origin This is don
82. ry cage motor mount and electronics plate These items took a lot of refining due to the tight tolerances I had to work with The motor mount was also extremely critical because it needed to be positioned precisely and be extremely robust I used Google SketchUp for all of my 3D models Some time was also spent cutting out the bottom of the tank and cleaning it out Along with this mechanical work I researched the drive system I picked out the front and rear sprocket sizes and got them ordered I used calculations to predict our final top speed The size of the chain was also important because I wanted it to be easy to replace with a standard 530 size motorcycle chain I picked ANSI 50 roller chain for this exact reason After finally getting the mechanical stuff sorted out with the machine shop I lent a little bit of assistance to Loren with the pcb design I really would just review his layouts and help him with hardware questions if he had them Through the pcb process him and I modified the schematic as well This was especially true after our design review when we added our battery monitoring differential amplifiers I picked out the parts and then Loren added them to the layout Spring break passed and our pcb came in I spent the next two weeks populating and debugging all of our hardware We had some power supply issues with our 20V rail Loren and I couldn t get our boost to work We replaced the part and still could not seem to get it function
83. s are accomplished in this routine This function is called whenever a timer interrupt takes place XOKCKCkCkCkCkCk kk kk kk kk kCk kk kc kckckckckckckokckokckok sk kk e kx void adc high void Throttl ADCONObits ACMOD1 0 GROUP A ADCONObits ACMODO 0 ADCHSbits GASEL1 0 ANO ADCHSbits GASEL0 0 ADCONObits GO 1 while ADCONObits GO throttle read ReadADC throttle avg 4 throttle read 6 throttle avg 10 if PORTCbits RC4 1 throttle throttle avg 2 Fall 2008 477 Final Report Micro Battery ADCONObits ACMOD1 0 GROUP A ADCONObits ACMODO 0 ADCHSbits GASEL1 1 AN8 ADCHSbits GASEL0 0 F F ADCONObits GO 1 while ADCONObits GO batt micro read ReadADC batt micro avg 9 batt micro avg batt micro read 10 batt micro disp batt micro avg 1 453 LOW PRIORITY ADC KKK RK KK KK Ck kk kk kk This is where the low priority analog to digital inputs are read The low priority interrupts were all of the batteries aside from the microprocessor battery They are still being updated quickly and accurately but simply not as often as the throttle and microprocessor battery This function is called in the while 1 loop nested in the main loop Thus it i
84. s called once per iteration of the main polling loop CKCKCkCkCkCkCk Ck k kCk kk kk kk kk I k ck k ckck ck k ck ck RAK ck ck ko ke ke x void adc low void Battery 1 ADCONObits ACMOD1 1 GROUP C ADCONObits ACMODO 0 ADCHSbits GCSEL1 0 AN6 ADCHSbits GCSELO 1 F F ADCONObits GO 1 while ADCONObits GO battl read ReadADC battl avg 9 battl avg tbattl read 10 F 5 Fall 2008 477 Final Report battl avg battl disp b batt avg battl battl div attl avg 1 557 display scaling Battery 2 ADCONObits AC ADCONObits AC ADCHSbits GASE ADCHSbits GASE ADCONObits GO while ADCONOb OD1 0 GROUP A ODO 0 11 0 ANA 0 1 1 its GO batt2 read ReadADC batt2 avg batt2 avg batt2 disp b 9 batt2 avg batt2 read 10 batt avg batt2 batt2 div att2 1 367 display scaling Battery 3 ADCONObits AC ADCONObits AC ADCHSbits GBSE ADCHSbits GBSE ADCONObits GO while ADCONOb OD1 0 GROUP B ODO 1 11 0 ANS 0 1 gt 1 its GO batt3 read ReadADC batt3 avg batt3 avg batt3 disp b 9 batt3 avg batt3 read 10 batt avg batt3 batt3 div att3 avg 1 371 Battery 4 ADCONObits AC ADCONObits AC ADCHSbits GDSE ADCHSbits GDSE ADCONObits GO while ADCONOb
85. s in the way Moto eV performs with respect to a motorcycle Since the DC brushed motor used to propel Moto eV does not need to be water cooled it will not require a radiator The other key points in the motorcycle patent were found in claim 3 These points revolved around the use of fairing to enclose and protect the devices on the motorcycle But the details of the fairing design are based around the radiator placement on the chassis in coordination with the instrument cluster and headlights Once again the lack of a radiator has shown substantial differences between the patented motorcycle and the Moto eV Electric Scooter Filing date January 31 1996 Claim 1 of the electric scooter patent explains that an electric scooter is an electrically powered device that has a front and rear wheel connected by a tube like structure The connector between the front and rear wheel must also lie below the center of the wheels parallel to the ground providing the place where the rider is to stand The electric motor is mounted on the rear wheel of the scooter which is powered by batteries mounted below the chassis of the scooter The primary purpose of the device is for powered travelling over the ground Claim 2 simply continued to dive into greater details about the same categories The motive for patent infringement would be the use of batteries mounted on the chassis to power the electric motor and propel the device via the rear wheel The Moto eV is
86. s than the period of the PWM A 20 kHz PWM frequency was chosen such that the motor spins as a frequency outside of the human hearing spectrum Debugging For debugging our processor the ICD2 development kit is once again showing its value The PIC18F4331 will connect to the development kit serially and will be extremely easy to debug and manipulate using the MPLAB software which is conveniently installed on a laptop to be flexible with the motorcycle It can also be powered from the USB port of the computer eliminating the need for an external power source Application Organization The software was originally planned to be organized using a hybrid polling system The rationale behind this approach was based around setting different flags for different interrupts based on the priority level of the interrupts The PIC18F4331 has the feature of setting certain interrupts as high priority and other interrupts as low priority If a high priority interrupt takes place it will override any operations taking place at the time even if the processor is in the middle of processing a low priority interrupt The use of multiple interrupts priorities and multiples timers eventually became more of a hassle and confusion than being useful Thus a single priority single timer interrupt scheme was reverted to This system will set priority levels 45 477 Final Report 2008 for certain inputs and processes simply by using a counter to al
87. sed to determine the speed at which the motor is rotating The timer module will be used for the interrupt service routine The timer 1 interrupt will be used to read the input values for the ADC every time the interrupt flag is set Timer 1 is set as a 16 bit timer which will run at 8 MHz speed of the internal oscillator the microchip This was accomplished easily using the lt timers h gt header file included with the MPLAB C18 compiler 44 477 Final Report 2008 The SCI module will be used to communicate with the LCD and the development kit during debugging protocol The usart h header file was used with the C18 compiler in order to initialize the processor to output the data to the LCD screen with just one data pin connecting the output TX pin to the data input pin of the display It also included a useful display functions so that the use of excessively large header files like stdio h could be avoided The PWM will be used for controlling the power level of the motor This is done using the PWMI output pin in coordination with the throttle input from the ADC The PTPERL and PTPERH register make up the PWM period settings These settings along with the clock speed and timer prescaler will determine the frequency of the PWM Timer 2 15 preconfigured to have its prescaler apply to the PWM frequency when the PWM signal is enabled The input throttle value is then scaled to such that the duty cycle resolution is les
88. sidered a motor vehicle to be used on public streets roads and highways Thus it is required to abide by the Federal Motor Vehicle Safety Standards FMVSS 19 The bike will need to be tested for different temperature ranges to ensure that all parts are able to withstand the low and high temperatures that the bike may encounter Then if there is a temperature range in which the bike does not function well the appropriate advisories can be placed in the user manual The bike is also not water proof therefore it will be advised to not use the bike when it is raining or snowing The bike should also be tested on pavement gravel dirt grass and any other possible terrains the driver may encounter It is considered a road ready motorcycle though and the rider will be advised to not drive the bike on rough terrains 25 477 Final Report 2008 In that case that it is necessary to take the Moto eV off road the manual will instruct to proceed with extreme caution With safety being the main concern there will be labels added on specific components of the bike to indicate a possible danger The most significant source of danger is the battery cage especially since the batteries will be in series with the capability of supplying 48 volts Therefore a label would be placed on the battery cage indicating the danger that could occur if one somehow managed to get short circuited The battery cage would also include a picture that
89. sign cost and ease of acquisition The chassis was purchased for 100 and required little maintenance to get it rolling This is a double cradle frame which will be advantageous when mounting the motor and batteries The negatives of this frame are its weight and size The frame is made of steel instead of the lighter alternative of aluminum and since the original motor was a 500cc v four the space that remained to install the batteries after placing the motor was limited Microcontroller When researching the different appropriate microcontrollers available for this project it was clear from the beginning that the PIC line was more appropriate than the offerings from Freescale Below is an outline of the two PIC micros that the team was deciding between 477 Final Report 2008 Table 3 1 Microcontrollers Under Consideration Features PIC18F4431 2 dsPIC30F3011 3 Peak Operating Frequency 40 MHz 10MIPS 30 MIPS Program Memory Bytes 16384 24000 I O Ports five 8 bit bidirectional ports 20 pins Capture Compare PWM modules 2 4 PWM 8 channels 6 channels 14 bit resolution Complement mode 14 bit resolution Complement mode Quadrature Encoder Interface YES YES ATD 10 bit High Speed 200ksps 9 input channels 2 comparators for 2 cannel simultaneous reads 10 bit High Speed 1Msps 9 channels 4 S H inputs for simultaneous reads Serial Communicatio
90. so sets the parameters of the drive circuitry which in turn apply the proper voltage and current to the motor 9 2 PCB Layout Design Considerations Overall The Moto eV PCB has a number of design considerations The PCB is partitioned into four quadrants all contained on one board These quadrants are power regulation analog I O digital I O and gate drive This is mainly to isolate any sensitive signals from noisy high frequency high current signals First the board requires a 12V input which will be passed through the LT1529 voltage regulator which supplies 5V to most of the PCB components 34 The reason such a high supply voltage was chosen is because the gate driver requires a 12V source and this way we will not need two separate batteries to operate the PCB A 48V source will also be attached to the PCB from our battery bank in order to monitor the charge level on the batteries The 48V pack the dirty supply and the 12V rail aka the clean supply share a common ground The second area is where the analog I O is placed This accommodates the throttle input shunt resistor input inclinometer and amplifier Noise on either the throttle or the shunt resistor lines can severely impact the performance of the bike These inputs are also located close to the micro to avoid long traces that can lead to parasitic inductances A standard 12 mils trace is used for this section Special care must be taken in the placement of the inclinomete
91. suitable donor I stripped it down cleaned it up replaced the steering stem bearings and reassembled it Over the break I also spent a significant amount of time looking for potential sponsors I emailed over 15 companies looking for various parts which could be donated or discounted These requests were met with various amounts of success Once the semester officially started I continued the search for parts I picked out most of the hardware we used and obtained a good deal of sponsorship For example our throttle LCD 48V power switch two fuses a master fuse mount and a fuse block were all 10096 donated to the project through my inquiries I also was able to obtain a 150 discount on our Mars brushed DC motor A lot of my time was spent picking out the pcb hardware as well A 3 477 Final Report 2008 Towards the end of the semester Loren and I obtained a 100 dollar donation for new tires from a complete stranger Loren and I had several meetings with professor Wasynczuk We discussed our motor drive circuitry We discussed using the IGBT modules that we had already purchased and the need for a bootstrap The bootstrap circuitry drives the upper gate We used the lower switch s diode as the freewheeling diode for the motor The next portion of the semester I was dedicated to designing the motor mount battery cage and electronics plate I used paper models of the motor and batteries to design cardboard models for the batte
92. tch Microprocessor fails to DMM Medium User input will be remains in shorts closed execute program non existent reset No power to Bypass No lean angle displayed DM Medium inclinometer Capacitor Shorts on LCD B2 No power to Bypass No battery level DMM Medium User will not know Battery Diff Capacitor shorts displayed on LCD how much charge is Amps left B3 No Power to Bypass Micro reads current as DMM High Can cause serious shunt Diff Capacitor shorts zero and applies full damage to critical Amp power to motor components and the rider 477 Final Report Fall 2008 Medium C2 C3 System Performance seems erratic Battery level seems erratic Battery level seems erratic Bypass Capacitor fails Boost feedback resistor fails causing unreliable output voltage Output capacitor fails Introduces noise into the system which causes output voltage to vary LCD displays false battery levels Micro reads current as zero and applies full power to motor Observation while riding Observation Observation Low Low Can cause unpredictable ride performance Boost reads unpredictable feedback voltage tries to correct output voltage 20V output switches over too large a range that diff amps fail to function properly 477 Final Report Fall 2008 Cannot control motor D2 High side gate not switching D3 No power to gate driver D4 High side IGBT switch stuck closed
93. terrupts There are an extensive number of initializations in the main loop First the oscillator clock speed is set to 8 MHz by configuring the OSCCON register Next the port status bits are initialized by setting the TRIS and PORT registers This defines which pins are used as an input and which pins are used as an output according to their function Then the and timer2 initializations are taken care of The timer 1 initialization is set for the main ISR and the timer 2 initialization is set for configuring the PWM frequency After that the ADC conversions settings are initialized to set the ADC clock speed acquisition time analog input channels and reference voltages 5 and 0 Then the USART registers are set for communicating with the LCD display This involves setting the transmission for 8 bit resolution a 9600 baud rate Asynchronous mode and enabling the communication Finally the PWM is configuring by manipulation a large number of registers and bits It is set up to function in free running mode 46 477 Final Report 2008 independent output for and to PWM timer base such that our PWM frequency optimizes output power while minimizing the noise from the motor Beside the initialization the main loop with have a while 1 loop nested in it that has been used to debug by testing basic led toggles thus far When the software is completely cleaned up and finalized the while loop in m
94. the Moto eV are Enertia Zero X as well as a few others but they tend to be more along the lines of a dirt bike or scooter However Honda and Yamaha are both planning on coming out with an electric motorcycles within the next two years Therefore the packaging methods of the products currently in the market were taken into consideration when coming up with the packaging for the Moto eV 7 2 1 Product 1 The Enertia Electric Motorcycle EEM is a new product that is just coming into market and being sold for 11 995 and weighs 280 pounds The EEM can travel 35 miles per charge with a top speed of 50 mph and a recharge time of 3 hours As for general dimensions the length of the EEM 15 80 with a body width of 12 5 and 19 5 from peg to peg The wheelbase will be 55 inches while the seat height is 33 inches Figure 1 29 477 Final Report Fall 2008 The motor is located on the chassis such that the output shaft delivers power directly through the chain to the back wheel Using a direct drive maximizes efficiency This is also the plan for the motor of the Moto eV The chassis of the is eng Figure 2 ply hold the motor and batteries Therefore the frame is a beam that holds three batteries on top and three on bottom with the motor located at the bottom of the frame The chassis weighs in at a total of 16 pounds The batteries packaging is ideal with this chassis but the Moto eV chassis is different and the ba
95. times of high load torques and low speeds As a backup method of motor control a voltage control method could be implemented It is important to make a microcontroller selection where this control option will be available in the future This contingency plan requires a high speed 10 bit PWM output which will be considered during microprocessor selection Other uses of the microcontroller will be to monitor amp display lean angles battery level ride mode and throttle levels 3 2 2 Interface Requirements Starting with the main motor control function the microcontroller will have to have PWM functionality to implement voltage control The motor driving signal will be optically isolated and will connect to the switching circuitry through a gate driver A serial communication interface will be needed to communicate with the Crystalfontz LCD Finally it is important to have a reasonable number excess of 6 of general digital pins to control things such as the ride mode and LCD backlight Input number one will be from the current monitoring circuitry This ATD input is essential for the motor control algorithm Two additional inputs will be used for the 0 5kQ potentiometer throttle and the tilt sensor intended to monitor lean angles Battery monitoring circuitry will interface via an ATD input Ride mode selection LCD display page selection and LCD backlight control will each use digital input pins 3 2 3 On Chip Peripheral Require
96. to eV 15 a street legal motorcycle it would require a license to drive which would also be clearly stated in the manual The manual will discuss the possible driving environments and how the motorcycle will react in all of the situations tested above and advise against driving on certain terrains and in specific weather conditions The manual will also specify how many riders are permitted at one time with respect to weight limit It would also advise wearing proper motorcycle gear which includes a helmet riding jacket and riding pants The warning labels will be explained in more details With the Moto eV 26 477 Final Report 2008 displaying the lean angle this leads to possible desire for competition in achieving a greater lean angle therefore the manual will indicate that the lean angle measurement is for safety and feedback purposes and not to be used as a means of competition Lastly the manual will provide contact information for Moto eV retailers maintenance and information for disposal recycling For additional safety there is a kill switch that will complete cut the power to the motor In the case of a defect or accident resulting in the gate drive getting stuck the motor can be disconnected from the power source to maintain control 6 3 Environmental Impact Analysis Besides just ethical concerns environmental impact also must be taken into consideration This can take place in any of the three stages of the li
97. ttery layout may not be the most space efficient or even possible depending on where the motor will have to be located in order to be in front of the swing arm 7 2 2 Product 2 Another electric motorcycle that is currently in the market is the Zero X The Zero is claiming to be the fastest cleanest and lightest electric motorcycle The Zero X is currently being sold for 7 450 and used for both off road and street purposes The frame weighs 18 pounds and the Zero X weighs in at only 140 pounds total The Zero X is powered by a lithium ion power pack that can be recharged in 2 hours The bike can travel up to 40 miles in one charge with a top speed being 55 mph Like the EEM the motor power is directly applied from the chain to the back wheel for efficiency The wheelbase will be 55 75 inches while the seat height is 35 5 inches 30 477 Final Report Fall 2008 With the lithium ion power pack the frame is more compact that the Moto eV layout This allows for a much smaller and light weight bike but also strays away from a motorcycle and towards a dirt bike 7 3 Project Packaging Specifications Packaging of the Moto eV revolves around the 1986 Honda VF500F chassis The motor is placed in the frame directly in front of the swingarm The battery pack is placed directly in front of the motor The battery pack consist of four 12 V batteries in a cage that uses the existing frame mounts The old tank was cut open and used for
98. was considered was Advanced DC A89 4001 series wound brushed DC motor The team was offered a used one for 350 plus shipping This motor has a continuous output of 6hp and a peak of 27hp A downside is that it weighs 50165 which is twice that of the Lemco This weight also corresponds to size with the A89 being over 10 4 long compared to the Lemco s depth of 170 2mm 6 7 It was important to try to keep the weight of each component to a minimum Once everything is in the chassis the weight of the bike will directly correspond to performance and range Another downfall of this motor was the lack of support It was difficult to find much information on this motor or any previous examples of electric vehicle implementation Seeing as how the motor was used the team also didn t know the condition of the brushes or any of the other mechanics Yet another pitfall for the A89 is its lack of efficiency The Lemco is the leader in efficiency as far as brushed DC motors go In the end the motor choice was the Mars ME0709 PM brushed DC motor 10 This motor weighs in at 36165 and a cost of 500 While the motor is twice the depth of the Lemco and heavier due to its lower price it is the winner It can operate between 48V and 72V with a continuous current draw of 114A The motor provides approximately 7 03kW of continuous power at 72V Running at 48V this number will be slightly reduced but is still more than enough to power a motorcycle LCD The
99. wires I also made multiple trips to ACE Hardware with the group to pick out hardware that we needed to mount our components to the frame and electronics plate Mike and I then painted the tank faring and battery cage I also cut all of our 4awg wires to length and attached the terminals and heat shrink Mike and I then ran the entire wiring harness and hooked up the four 12V batteries with their chargers and monitoring wires After all of the hardware was completed I started working on the code I created the inclinometer lookup table and wrote the code to read the ADC pin and output the correct angle I also wrote the battery monitoring code and spent a lot of time with Arin trying to figure out our ADC initialization issue Once all the code and hardware was done Mike and I spent a considerable amount of time debugging our motor control circuit and figured out why our GPIO pins were messing with our control algorithm 7 477 Final Report 2008 Appendix B Packaging Figure B 1 Battery Cage 1 Figure B 2 Battery Cage 2 B 1 477 Final Report Figure Battery and Motor Placement Front 11 5000 10 7500 Figure B 4 Battery and Motor Placement Side B 2 Fall 2008 477 Final Report 2008 Figure B 5 Battery and Motor Placement Isotropic Figure B 6 Electronics Plate 90 Degrees B 3 477 Final Report 2008 Figure B 7 Motor Mount
100. y as a percentage 4 12 Volt 18 Amp hour sealed lead acid batteries to power the motor and one 12 Volt sealed lead acid 7 5 Amp hour battery to power the PIC18F4331 the tilt angle from the inclinometer the ride mode and possibly a range value associated with the battery charge remaining The final function motor will contain the commands associated with powering the motor via the PWM It is where the duty cycle is scaled to relate to the PWM timer scaling This function also has some bit shifting that needs to take place to use the specific 12 bits that are allocated for the duty cycle high and low registers PDCOH and PDCOL of these functions are written into the same file instead of using separate files and calling them into the main file Including a significant amount of commented lines and test code 47 477 Final Report 2008 included at this point complete code is still less than 400 lines It would seem a bit over the top to split this software into multiple files 10 4 Summary The software involved to control and power Moto eV is fairly straight forward and simple The majority of the control is accomplished by the ADC module which is driven by an ISR using a built in timer that is driven by the internal oscillator in the PIC18F4331 The values read from the ADC will be averaged and used directly when displayed as feedback information or used indirectly with the PWM module to control the power output

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