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SimElectronics User's Guide

1. ev 2 15 2 Modeling an Electronic System 2 16 SPICE Diode This model approximates a SPICE diode You specify both model card and instance parameters as instance parameters on this mask The instance parameter OFF and the noise model parameters KF and AF are not supported Additional instance parameters are SCALE and TOFFSET SCALE is the number of parallel diode instances for this device SCALE multiplies the output current and device charge directly This differs from the AREA parameter which multiples the device parameters IS CJO and IBV and divides RS You can set the diode temperature to a fixed temperature or to the circuit temperature from the SPICE Environment Parameters block plus TOFFSET The block lets you include or exclude capacitance modeling initial conditions and reverse breakdown modeling The capacitance modeling uses the published equations which may yield a slightly different value than SPICE for capacitance The initial condition VO is the voltage across the internal diode junction so it is only effective when junction capacitance is present The breakdown voltage BV is not adjusted as a function of the breakdown current IBV Settings Main Junction Capacitance Reverse Breakdown Temperature Model reverse breakdown Yes Reverse breakdown current IBV 0 005 Reverse breakdown voltage BV 4 3 ok
2. 1 14 Specifying Simulation Accuracy Speed Tradeoff 1 14 Avoiding Simulation Issues 1 15 Running a Time Domain Simulation 1 16 Running a Small Signal Frequency Domain Analysis 1 16 vi Contents DC Motor Model gt ae KK KK KK KK 1 17 Overview of DC Motor Example 1 17 Selecting Blocks to Represent System Components 1 17 Building th 1 18 Specifying Model Parameters 1 20 Configuring the Solver Parameters 1 26 Running the Simulation and Analyzing the Results 1 27 Triangle Wave Generator Model 1 30 Overview of Triangle Wave Generator Example 1 30 Selecting Blocks to Represent System Components 1 30 Building the 1 1 32 Specifying Model Parameters 1 33 Configuring the Solver Parameters 1 41 Running the Simulation and Analyzing the Results 1 42 Modeling an Electronic System 2 Parameterizing Blocks from Datasheets 2 2 Parameterize a Piecewise Linear Diode Model 2 4 Parameterize an Exponential Diode from a Datasheet 2 8 Parameterize an Exponential Diode from SPICE Netlist 2 13 Parameterize an Op Amp from a Datasheet 2 17 Additional Parameterization Workflows
3. 2 19 Validation Using Data from SPICE Tool 2 19 Parameter Tuning Against External Data 2 19 Building an Equivalent Model of a SPICE Netlist 2 19 Selecting the Output Model for Logic Blocks 2 20 Available Output Models 2 20 Quadratic Model Output and Parameters 2 21 Simulating Thermal Effects in Semiconductors 2 24 Using the Thermal Ports 2 24 Thermal Model for Semiconductor Blocks Thermal Mass Parameterization Electrical Behavior Depending on Temperature Improving Numerical Performance Simulating Thermal Effects in Rotational and Translational Actuators Using the Thermal Ports Thermal Model for Actuator Blocks 2 26 2 27 2 27 2 28 2 29 2 29 2 31 vii Getting Started SimElectronics Product Description on page 1 2 SimElectronics Assumptions and Limitations on page 1 3 Modeling Physical Networks with SimElectronics Blocks on page 1 4 Required and Related Products on page 1 5 SimElectronics Block Libraries on page 1 6 Modeling Electronic and Electromechanical Systems on page 1 9 Essential Electronic Modeling Techniques on page 1 10 Simulating an Electronic System on page 1 14 DC Motor Model on page 1 17 Triangle Wave Generator Mode
4. SimElectronics User s Guide MATLAB amp SIMULINK R201 5b How to Contact MathWorks Latest news www mathworks com Sales and services www mathworks com sales and services User community www mathworks com matlabcentral Technical support www mathworks com support contact us Phone 508 647 7000 The MathWorks Inc 3 Apple Hill Drive Natick MA 01760 2098 SimElectronics User s Guide COPYRIGHT 2008 2015 by The MathWorks Inc The software described in this document is furnished under a license agreement The software may be used or copied only under the terms of the license agreement No part of this manual may be photocopied or reproduced in any form without prior written consent from The MathWorks Inc FEDERAL ACQUISITION This provision applies to all acquisitions of the Program and Documentation by for or through the federal government of the United States By accepting delivery of the Program or Documentation the government hereby agrees that this software or documentation qualifies as commercial computer software or commercial computer software documentation as such terms are used or defined in FAR 12 212 DFARS Part 227 72 and DFARS 252 227 7014 Accordingly the terms and conditions of this Agreement and only those rights specified in this Agreement shall pertain to and govern the use modification reproduction release performance display and disclosure of the Program and Documentation by the fede
5. 1 7 To where Ris the resistance at temperature T Ro is the resistance at the measurement or reference temperature a is the resistance temperature coefficient A typical value for copper is 0 00393 K 2 31
6. 2 10 Parameterize an Exponential Diode from a Datasheet Diode This block represents a diode Use the Diode model parameter to select one of the following model types 1 Piecewise Linear Diode This option invokes the diode model from the Simscape Foundation Library 2 Piecewise Linear Zener Diode i e piecewise linear diode with reverse breakdown characteristics This model is identical to the Piecewise Linear Diode for reverse voltages above the Reverse Breakdown Voltage Vz For voltages below Vz the diode breaks down with a low corresponding Zener Resistance Rz Exponential Diode Uses the standard exponential diode equation I Is exp V N Vt 1 where Is is the Saturation current Vt is the thermal voltage and is the emission coefficient gt 1 Vt is given by Vt k T e where k is Boltzmann s constant T is the absolute Temperature of the p n junction and e is the magnitude of charge on an electron Settings Main Reverse Breakdown Ohmic Resistance Capacitance i Temperature Dependence Ohmic resistance RS 0 01 Ohm cence harep Apply 2 11 2 Modeling an Electronic System Diode This block represents a diode Use the Diode model parameter to select one of the following model types 1 Piecewise Linear Diode This option invokes the diode model from the Simscape Foundation Library 2 Piecewise Linear Zener Diode i e piecewise linear d
7. Junction case and case ambient or case heatsink thermal resistances JC CA A row vector R_CA of two thermal resistance values represented by the two Conductive Heat Transfer blocks in the Thermal Model for Semiconductor Blocks on page 2 26 The first value R_JC is the thermal resistance between the junction and case The second value R_CA is the thermal resistance between port H and the device case See Thermal Model for Semiconductor Blocks on page 2 26 for further details The default value is 0 10 K W Thermal mass parameterization Select whether you want to parameterize the thermal masses in terms of thermal time constants By thermal time constants or specify the thermal mass values directly By thermal mass For more information see Thermal Mass Parameterization on page 2 27 The default is By thermal time constants Junction and case thermal time constants t J t C A row vector J 1 C of two thermal time constant values The first value J is the junction time constant The second value C is the case time constant This parameter is only visible when you select By thermal time constants for the Thermal mass parameterization parameter The default valueis O 10 s Junction and case thermal masses M_J M C A row vector M J M C of two thermal mass values The first value M J is the junction thermal mass The second value M C is the case thermal mass This pa
8. Parameterize an Op Amp from a Datasheet Parameterize an Op Amp from a Datasheet The Triangle Wave Generator example model also described in Triangle Wave Generator Model on page 1 30 contains two op amps parameterized based on a datasheet for an LM7301 The National Semiconductor datasheet gives the following data for this device Gain 97dB 7 1e4 Input resistance 39MQ Slew rate 1 25V us Bandwidth 4MHz The Band Limited Op Amp and Finite Gain Op Amp blocks have been designed to work from manufacturer datasheets Implementing detailed op amp device models derived from manufacturer SPICE netlist models is not recommended because it provides more accuracy than is typically warranted and slows down simulations The simple parameterization of the Sim Electronics op amp blocks allows you to determine the sensitivity of your circuit to abstracted performance values such as maximum slew rate and bandwidth Because of this behavior based parameterization you can determine which specification of op amp is required for a given application A circuit designer can later match these behavioral parameters determined from the model against specific op amp devices Based on the datasheet values above set the Band Limited Op Amp block parameters as follows Gainsetto7 1e4 Input resistance Rin set to 39e6Q Output resistance Rout set to zero The value is not defined but will be small compared to
9. Specifying Simulation Accuracy Speed Tradeoff on page 1 14 Avoiding Simulation Issues on page 1 15 Running a Time Domain Simulation on page 1 16 Running a Small Signal Frequency Domain Analysis on page 1 16 Selecting a Solver SimElectronics software supports all of the continuous time solvers that Simscape supports For more information see Setting Up Solvers for Physical Models in the Simscape documentation You can select any of the supported solvers for running a SimElectronics simulation The variable step solvers ode23t and ode15s are recommended for most applications because they run faster and work better for systems with a range of both fast and slow dynamics The ode23t solver is closest to the solver that SPICE traditionally uses To use Simulink Coder software to generate standalone C or C code from your model you must use the ode14x solver For more information about code generation see Code Generation in the Simscape documentation Specifying Simulation Accuracy Speed Tradeoff To trade off accuracy and simulation time adjust one or more of the following parameters Relative tolerance in the Configuration Parameters dialog box Absolute tolerance in the Configuration Parameters dialog box Max step size in the Configuration Parameters dialog box Constraint Residual Tolerance in the Solver Configuration block dialog box In most cases the default tolerance
10. on page 1 30 1 Getting Started SimElectronics Product Description Model and simulate electronic and mechatronic systems SimElectronics provides component libraries for modeling and simulating electronic and mechatronic systems The libraries include models of semiconductors motors drives sensors and actuators You can use these components to develop electromechanical actuation systems and to build behavioral models for evaluating analog circuit architectures in Simulink Sim Electronics models can be used to develop control algorithms in electronic and mechatronic systems including vehicle body electronics aircraft servomechanisms and audio power amplifiers The semiconductor models include nonlinear and dynamic temperature effects enabling you to select components in amplifiers analog to digital converters phase locked loops and other circuits You can parameterize your models using MATLAB variables and expressions You can add mechanical hydraulic pneumatic and other components to a model using Simscape and test them in a single simulation environment To deploy models to other simulation environments including hardware in the loop HIL systems SimElectronics supports C code generation Key Features Libraries of electronic and electromechanical components with physical connections including sensors semiconductors and actuators Parameterization options enabling key parameter values to be entered direc
11. Capacitance Temperature Dependence X Zener resistance Rz 2 Ohm Reverse breakdown voltage Vz 4 3 ok cmeer Parameterize a Piecewise Linear Diode Model Diode This block represents a diode Use the Diode model parameter to select one of the following model types 1 Piecewise Linear Diode This option invokes the diode model from the Simscape Foundation Library 2 Piecewise Linear Zener Diode i e piecewise linear diode with reverse breakdown characteristics This model is identical to the Piecewise Linear Diode for reverse voltages above the Reverse Breakdown Voltage Vz For voltages below Vz the diode breaks down with a low corresponding Zener Resistance Rz Exponential Diode Uses the standard exponential diode equation I Is exp V N Vt 1 where Is is the Saturation current Vt is the thermal voltage and N is the emission coefficient gt 1 Vt is given by Vt k T e where k is Boltzmann s constant T is the absolute Temperature of the p n junction and e is the magnitude of charge on an electron Reverse Breakdown Ohmic Resistance Capacitance Temperature Dependence X Settings Junction capacitance pF ok 2 7 2 Modeling an Electronic System Parameterize an Exponential Diode from a Datasheet Example 1 uses a piecewise linear approximation to the diode s exponential current vo
12. Dependence Zener resistance Rz 2 Ohm Y Reverse breakdown voltage Vz 4 3 X Apply The Voltage Sensor block does not have any parameters Accept the default parameters for the Variable Resistor block These parameters establish the units of the physical signal at the block output such that they match the expected default units of the Variable Resistor block input Set the Capacitor block parameters as follows Capacitance 2 5e 9 Initial voltage 0 08 This value starts the oscillation in the feedback loop Series resistance 0 1 39 1 Getting Started 1 40 Capacitor Models a linear capacitor The relationship between voltage V and and current I is I C dV dt where C is the capacitance in farads The Series resistance and Parallel conductance represent small parasitic effects The parallel conductance can be used to model dielectric losses and the series resistance used to represent the effective series resistance ESR of the capacitor Simulation of some circuits may require the presence of the small series resistance Consult the documentation for further details Source code Settings Parameters Variables Capacitance F Series resistance Ohm Parallel conductance 1 Ohm 7 Set the DC Voltage Source block parameters as follows Constant voltage 0 DC Voltage Source The ideal voltage
13. Simscape and SimElectronics blocks and then develop the controller or signal processing algorithm in Simulink For more information about modeling the physical system see Essential Electronic Modeling Techniques on page 1 10 Define component data by specifying electrical or mechanical properties as defined on a datasheet For more information about parameterizing blocks see Parameterizing Blocks from Datasheets on page 2 2 Configure the solver options For more information about the settings that most affect the solution of a physical system see Setting Up Solvers for Physical Models in the Simscape documentation Run the simulation For more information on how to perform time domain simulation of an electronic system see Simulating an Electronic System on page 1 14 1 Getting Started Essential Electronic Modeling Techniques 1 10 In this section Overview of Modeling Rules on page 1 10 Required Blocks on page 1 11 Creating a New Model on page 1 12 Modeling Instantaneous Events on page 1 12 Using Simulink Blocks to Model Physical Components on page 1 12 Overview of Modeling Rules SimElectronics models are essentially Simscape block diagrams To build a system level model with electrical blocks use a combination of SimElectronics blocks and other Simscape and Simulink blocks You can connect SimElectronics blocks directly to Simscape block
14. and e is the magnitude of charge on an electron Settings Main Reverse Breakdown Ohmic Resistance Capacitance i Temperature Dependence Diode model Exponential Parameterization Use two EV curve data points Currents 11 I2 5250 Voltages V1 V2 0 7 1 0 Measurement temperature 25 ok cmer ev 2 9 2 Modeling an Electronic System Diode This block represents a diode Use the Diode model parameter to select one of the following model types 1 Piecewise Linear Diode This option invokes the diode model from the Simscape Foundation Library 2 Piecewise Linear Zener Diode i e piecewise linear diode with reverse breakdown characteristics This model is identical to the Piecewise Linear Diode for reverse voltages above the Reverse Breakdown Voltage Vz For voltages below Vz the diode breaks down with a low corresponding Zener Resistance Rz Exponential Diode Uses the standard exponential diode equation I Is exp V N Vt 1 where Is is the Saturation current Vt is the thermal voltage and is the emission coefficient gt 1 Vt is given by Vt k T e where k is Boltzmann s constant T is the absolute Temperature of the p n junction and e is the magnitude of charge on an electron Settings Main Reverse Breakdown Ohmic Resistance Capacitance Temperature Dependence X Reverse breakdown voltage BV 4 3
15. datasheet and the underlying model is simpler than that typically used by specialist EDA simulation tools The smaller number of parameters and simpler underlying models can support MATLAB system performance analysis better and thereby support design choices Following system design you can perform validation in hardware or more detailed modeling and validation using an EDA simulation tool The following parameterization examples illustrate various block parameterization techniques Example 1 Parameterize a Piecewise Linear Diode Model on page 2 4 Example 2 Parameterize an Exponential Diode from a Datasheet on page 2 8 Example 3 Parameterize an Exponential Diode from SPICE Netlist on page 2 13 Example 4 Parameterize an Op Amp from a Datasheet on page 2 17 Most of the time datasheets should be a sufficient source of parameters for SimElectronics blocks see Examples 1 2 and 4 Sometimes there is need for more information than is available on the datasheet and data can be augmented from a manufacturer SPICE netlist For example circuit performance may depend on one or two critical components and increased accuracy is needed either for parameter values or the underlying model Sim Electronics libraries contain a SPICE compatible sublibrary to support this case and this is illustrated by Example 3 If you have many components that need to be modeled to a high level of accuracy then Simulink cosimulation with a specia
16. for 096 duty 0 v cycle Input value Vmax for 100 duty 5 v cycle Output voltage amplitude 5 Simulation mode Averaged M 3 H Bridge block parameters as follows Simulation mode Averaged This value tells the block to generate an output signal whose value is the average value of the PWM signal Simulating the motor with an averaged signal estimates the motor behavior in the presence of a PWM signal To validate this approximation use value of PWM for this parameter 1 23 1 Getting Started 1 24 H Bridge This block represents an H bridge motor drive The block can be driven by the Controlled PWM Voltage block in PWM or Averaged mode In PWM mode the motor is powered if the PWM port voltage is above the Enable threshold voltage In Averaged mode the PWM port voltage divided by the PWM signal amplitude parameter defines the ratio of the on time to the PWM period Using this ratio and assumptions about the load the block applies an average voltage to the load that achieves the correct average load current The Simulation mode parameter value must be the same for the Controlled PWM Voltage and H Bridge blocks If the REV port voltage is greater than the Reverse threshold voltage then the output voltage polarity is reversed If the BRK port voltage is greater than the Braking threshold voltage then the output terminals are short circuited via one bridge arm in series with the parallel com
17. for the electrical equations by setting the Parameterization parameter on the Thermal Dependence tab to None Simulate at parameter measurement temperature The thermal time constants are generally much slower than electrical time constants so the thermal aspects of your model are unlikely to dictate the maximum fixed time step you can simulate at for example for hardware in the loop simulations However if you need to remove detail for example to speed up simulation the junction thermal mass time constant is typically an order of magnitude faster than the case thermal mass time constant You can remove the effect of the junction thermal mass by setting the junction thermal mass to zero and also setting the junction case thermal resistance to zero Simulating Thermal Effects in Rotational and Translational Actuators Simulating Thermal Effects in Rotational and Translational Actuators In this section Using the Thermal Ports on page 2 29 Thermal Model for Actuator Blocks on page 2 31 Using the Thermal Ports All blocks that represent rotational and translational actuators with electrical windings can optionally show a thermal port for each electrical winding So for example A DC Motor block can optionally show a single thermal port corresponding to the armature A Shunt Motor block can optionally show two thermal ports one for the stator winding and one for the field winding The therm
18. normal conditions and when the logic gate drives other high impedance CMOS gates The block sets the value of the gate output capacitor such that the resistor capacitor time constant equals the Propagation delay parameter value The linear output model is shown in the following illustration Gste output Electrical Reference Quadratic Models the gate output in terms of a complementary N channel and P channel MOSFET pair This adds more fidelity which becomes relevant if drawing higher currents from the gate output or if exercising the gate under fault conditions In addition the gate input demand is lagged to approximate the Propagation delay parameter value Default parameters are representative of the 74HC logic gate family The quadratic output model is shown in the next illustration 2 20 Selecting the Output Model for Logic Blocks V C Voltage LLLI Source PS Constant Veco le Logicdemand PS Subtract 1st order lag propagation delay Use the Output current voltage relationship parameter on the Outputs tab of the block dialog box to specify the output model For most system models MathWorks recommends selecting the linear option because it supports faster simulation If necessary you can use the more detailed output model to validate simulation results obtained from the simpler model Quadratic Model Output and Parameters If you select the quadratic model use the following parameters
19. range to 2 27 2 Modeling an Electronic System 2 28 be simulated or where the primary task of the simulation is to capture the heat generated to support system level design The thermal port and the Thermal Port tab of the block dialog box let you simulate the generated heat and device temperature The Thermal Dependence tab of the block dialog box lets you model the effect of temperature of the semiconductor junction on the electrical equations Therefore To simulate all the temperature effects show the block s thermal port and set the Parameterization parameter on the Thermal Dependence tab to Model temperature dependence or for blocks with a choice of options for modeling temperature dependence select one of these options for example Use an I V data point at second measurement temperature To simulate just the generated heat and device temperature show the block s thermal port but set the Parameterization parameter on the Thermal Dependence tab to None Simulate at parameter measurement temperature Improving Numerical Performance It is very important that you set realistic values for thermal masses and resistances Otherwise junction temperatures can become extreme and out of range for valid results which in turn may manifest itself as numerical difficulties when simulating A simple test to see if numerical difficulties are a result of unrealistic thermal values is to turn off the temperature dependence
20. to control the block output Supply voltage Supply voltage value Vcc applied to the gate in your circuit The default value is 5 V Measurement voltage The gate supply voltage for which mask data output resistances and currents are defined The default value is 5 V Logic HIGH output resistance at zero current and at I OH A row vector OHI R_OH2 of two resistance values The first value R_OH1 is the gradient of the output voltage current relationship when the gate is logic HIGH and there is no 2 21 2 Modeling an Electronic System 2 22 output current The second value R_OH2 is the gradient of the output voltage current relationship when the gate is logic HIGH and the output current is OH The default valueis 25 250 10 Logic HIGH output current I OH when shorted to ground The resulting current when the gate is in the logic HIGH state but the load forces the output voltage to zero The default value is 63 mA Logic LOW output resistance at zero current and at I OL A row vector OLI R OL2 of two resistance values The first value R_OL1 is the gradient of the output voltage current relationship when the gate is logic LOW and there is no output current The second value R_OL2 is the gradient of the output voltage current relationship when the gate is logic LOW and the output current is OL The default valueis 30 800 10 Logic LOW output current I OL when shorted to Vcc The resu
21. values produce accurate results without sacrificing unnecessary simulation time The parameter value that 1s most likely to be inappropriate Simulating an Electronic System for your simulation is Max step size because the default value auto depends on the simulation start and stop times rather than on the amount by which the signals are changing during the simulation If you are concerned about the solver missing significant behavior change the parameter to prevent the solver from taking too large a step The Simulink documentation describes the following parameters in more detail and provides tips on how to adjust them Relative tolerance Absolute tolerance Max step size The Solver Configuration block reference page in the Simscape documentation explains when to adjust the Constraint Residual Tolerance parameter value Avoiding Simulation Issues If you experience a simulation issue first read Troubleshooting Simulation Errors in the Simscape documentation to learn about general troubleshooting techniques Note SimElectronics software does not have the ability to model large circuits with dozens of analog components If you encounter convergence issues when trying to simulate a model with more than a few tens of transistors you may find that the limitations of SimElectronics software prevent you from achieving convergence with any set of simulation parameter values There are a few techniques
22. wave in the Scope window double click the Scope block You can do this before or after you run the simulation The following plot shows the voltage waveform As the resistance of the Variable Resistor block increases the amplitude of the output waveform increases and the frequency decreases Triangle Wave Generator Model 0 Time offset 0 Triangle Waveform Voltage 1 43 Modeling an Electronic System Parameterizing Blocks from Datasheets on page 2 2 Parameterize a Piecewise Linear Diode Model on page 2 4 Parameterize an Exponential Diode from a Datasheet on page 2 8 Parameterize an Exponential Diode from SPICE Netlist on page 2 13 Parameterize an Op Amp from a Datasheet on page 2 17 Additional Parameterization Workflows on page 2 19 Selecting the Output Model for Logic Blocks on page 2 20 Simulating Thermal Effects in Semiconductors on page 2 24 Simulating Thermal Effects in Rotational and Translational Actuators on page 2 29 2 Modeling an Electronic System Parameterizing Blocks from Datasheets SimElectronics software is a system level simulation tool which provides blocks with a commensurate level of fidelity Block parameters are designed where possible to match the data found on manufacturer datasheets For example the bipolar transistor blocks support parameterization in terms of the small signal quantities usually quoted on a
23. 2 Specifying Model Parameters on page 1 33 Configuring the Solver Parameters on page 1 41 Running the Simulation and Analyzing the Results on page 1 42 Overview of Triangle Wave Generator Example In this example you model a triangle wave generator using SimElectronics electrical blocks and custom SimElectronics electrical blocks and then look at the voltage at the wave generator output You use a classic circuit configuration consisting of an integrator and a noninverting amplifier to generate the triangle wave and use datasheets to specify block parameters For more information see Parameterizing Blocks from Datasheets on page 2 2 To see the completed model open the Triangle Wave Generator example Selecting Blocks to Represent System Components First you select the blocks to represent the input signal the triangle wave generator and the output signal display You model the triangle wave generator with a set of physical blocks bracketed by a Simulink PS Converter block and a PS Simulink Converter block The wave generator consists of Two operational amplifier blocks Resistors and a capacitor that work with the operational amplifiers to create the integrator and noninverting amplifier Simulink PS Converter and PS Simulink Converter blocks The function of the Simulink PS Converter and PS Simulink Converter blocks is to bridge the physical part of the model which uses physical sign
24. Revised for Version 2 0 Release 2011b Revised for Version 2 1 Release 2012a Revised for Version 2 2 Release 2012b Revised for Version 2 3 Release 2013a Revised for Version 2 4 Release 2013b Revised for Version 2 5 Release 2014a Revised for Version 2 6 Release 2014b Revised for Version 2 7 Release 2015a Revised for Version 2 8 Release 2015b Contents Getting Started SimElectronics Product Description 1 2 Key features vete Vr Rear ES UU Ep Rey 1 2 SimElectronics Assumptions and Limitations 1 3 Modeling Physical Networks with SimElectronics Blocks 1 4 Required and Related Products 1 5 Product Requirements 1 5 Other Related Products 1 5 SimElectronics Block Libraries 1 6 Overview of SimElectronics Libraries 1 6 Opening SimElectronies Libraries 1 6 Modeling Electronic and Electromechanical Systems 1 9 Essential Electronic Modeling Techniques 1 10 Overview of Modeling Rules 1 10 Required Blocks 1 11 Creating a New 1 1 12 Modeling Instantaneous Events 1 12 Using Simulink Blocks to Model Physical Components 1 12 Simulating an Electronic System 1 14 Selecting a Solver
25. Scope Simulink gt Commonly Used Blocks 1 Band Limited Op Simscape gt SimElectronics gt Integrated 2 Amp Circuits Diode Simscape gt SimElectronics gt 2 Semiconductor Devices 1 32 Triangle Wave Generator Model Note You can use the Simscape function ssc_new with a domain type of electrical to create a Simscape model that contains the following blocks Simulink PS Converter PS Simulink Converter Scope Solver Configuration Electrical Reference This function also selects the Simulink ode15s solver 3 Connect the blocks as shown in the following figure Resistor2 E gt e Sine Wave Simulirk PS Converter Variable Resistor Band Limited Op Amp Resistor1 PS Simulink Converter Now you are ready to specify block parameters Specifying Model Parameters Specify the following parameters to represent the behavior of the system components 1 33 1 Getting Started 1 34 Model Setup Parameters on page 1 34 Input Signal Parameters on page 1 34 Triangle Wave Generator Parameters on page 1 35 Signal Display Parameters on page 1 41 Model Setup Parameters The following blocks specify model information that is not specific to a particular block Solver Configuration Electrical Reference As with Simscape models you must include a Solver Configuration block in each topologically distinct physical network This example has a single physical n
26. V 3e 6 S Reverse breakdown voltage Vz This parameter should be set to the datasheet working voltage parameter 4 3V Parameterize a Piecewise Linear Diode Model Zener resistance Rz This needs to be set to a suitable small number Too small and the voltage current relationship becomes very steep and simulation convergence may not be as efficient Too large and the zener voltage will be incorrect For the Diode block to be representative of the real device the simulated reverse voltage should be close to 4 3V at 5mA the reverse bias current provided by the circuit Allowing a 0 01 V error on the zener voltage at Rz will be 0 01V 5mA 2 Q Junction capacitance This parameter is set to the datasheet diode capacitance value 450 pF Diode This block represents a diode Use the Diode model parameter to select one of the following model types 1 Piecewise Linear Diode This option invokes the diode model from the Simscape Foundation Library 2 Piecewise Linear Zener Diode i e piecewise linear diode with reverse breakdown characteristics This model is identical to the Piecewise Linear Diode for reverse voltages above the Reverse Breakdown Voltage Vz For voltages below Vz the diode breaks down with a low corresponding Zener Resistance Rz 3 Exponential Diode Uses the standard exponential diode equation I Is exp V N Vt 1 where Is is the Saturation current Vt is the thermal voltage and is th
27. al port represents copper resistance losses which convert electrical power to heat These losses are sometimes referred to as i R losses The thermal ports do not represent iron losses due to for example Eddy currents and hysteresis The thermal ports are hidden by default To expose the thermal port on a particular block instance in your block diagram 1 Right click the block where you want to show the thermal port 2 From the context menu select Simscape gt Block choices gt Show thermal port t Simscape b Log simulation data Explore Block choices No thermal port a OREL v Show thermal port 12 Cut Ctrl X View simulation data p Ha Ctrl C Paste Ctrl V When the thermal port is exposed the block dialog box contains two additional tabs Temperature Dependence and Thermal Port For actuator blocks with single winding these tabs always contain the same set of parameters 2 29 2 Modeling an Electronic System 2 30 Parameters Electrical Torque Mechanical Temperature Dependence Thermal Port Resistance temperature coefficient 0 00393 1K Measurement temperature 25 Resistance temperature coefficient Parameter a in the equation defining resistance as a function of temperature as described in Thermal Model for Actuator Blocks on page 2 31 The default value is for copper and is 0 00393 1 K Measurement temperature The temperature for which mo
28. als and the rest of the model which uses unitless Simulink signals Triangle Wave Generator Model You have a manufacturer datasheet for the two operational amplifiers you want to model Later in the example you use the datasheet to parameterize the SimElectronics Band Limited Op Amp block The following table describes the role of the blocks that represent the system components Block Description Sine Wave Generates a sinusoidal signal that controls the resistance of the Variable Resistor block Simulink PS Converts the sinusoidal Simulink signal to a physical signal Converter Solver Defines solver settings that apply to all physical modeling Configuration blocks Electrical Reference Provides the electrical ground Capacitor Works with an operational amplifier and resistor block to create the integrator Resistor Works with the operational amplifier and capacitor blocks to create the integrator and noninverting amplifier Variable Resistor Supplies a time varying resistance that adjusts the gain of the integrator which in turn varies the frequency and amplitude of the generated triangular wave DC Voltage Source Generates a DC reference signal for the operational amplifier block of the noninverting amplifier Voltage Sensor Converts the electrical voltage at the output of the integrator into a physical signal proportional to the current PS Simulink Converter Conve
29. ation Campaneats Simulink Coder Simulink Control Desin E Additional E Design Optimize Components 4 D Using the Command Prompt to Access the Block Libraries Another way to access the block libraries is to open them individually by using the command prompt To open just the SimElectronics library type elec_1ib in the MATLAB Command Window To open the Simscape library to access the utility blocks as well as electrical sources sensors and other Foundation library blocks type simscape in the MATLAB Command Window Toopen the main Simulink library to access generic Simulink blocks type simulink in the MATLAB Command Window The SimElectronics library window is shown in the following figure Each icon in the window represents a library Some of these libraries contain second level sublibraries Double click an icon to open the corresponding library 1 Getting Started Actustors amp Drivers Integrated Circuits Sources Semiconductor Devices Additional Components Modeling Electronic and Electromechanical Systems Modeling Electronic and Electromechanical Systems When you model and analyze an electronic or electromechanical system using SimElectronics software your workflow might include the following tasks 1 Create a Simulink model that includes electronic or electromechanical components In the majority of applications it is most natural to model the physical system using
30. bination of a second bridge arm and a freewheeling diode Voltages at ports PWM REV and BRK are defined relative to the REF port Settings Simulation Mode amp Load Assumptions Input Thresholds 1 Bridge Parameters Simulation mode Averaged z Load current characteristics Smoothed z Apply Motor Parameters Configure the block that models the motor Set the Motor block parameters as follows leaving the unit settings at their default values where applicable Electrical Torque tab Model parameterization By rated power rated speed amp no load speed Armature inductance 0 01 No load speed 4000 Rated speed at rated load 2500 Rated load mechanical power 10 Rated DC supply voltage 12 Mechanical tab DC Motor Model Rotor inertia 2000 Rotor damping 1e 06 Current Display Parameters Specify the parameters of the blocks that create the motor current display Current Sensor block PS Simulink Converter1 block Scopel block Of the three blocks only the PS Simulink Converter1 block has parameters Set the PS Simulink Converter1 block Output signal unit parameter to A to indicate that the block input signal has units of amperes PS Simulink Converter Converts the input Physical Signal to a unitless Simulink output signal The unit expression in Output signal unit parameter must match or be commensurate with the unit o
31. control see Zero crossing control in the Simulink documentation Using Simulink Blocks to Model Physical Components To run a fast simulation that approximates the behavior of the physical components in a system you may want to use Simulink blocks to model of one or more physical components The Modeling an Integrated Circuit example uses Simulink to model a physical component The Behavioral Model part of the example includes a subsystem comprised of Simulink blocks that implements the custom integrated circuit behavior Essential Electronic Modeling Techniques s lere gt Simulink PS Custom nii Converter circuit behavior defined in Simulink Push Pull Output Logical Dats Conversion Propagation E Operator Delay Compare To Constant 2 The Simulink Logical Operator block implements the behavioral model of the two input NOR gate Using Simulink in this manner introduces algebraic loops unless you place a lag somewhere between the physical signal inputs and outputs In this case a first order lag is included in the Propagation Delay subsystem to represent the delay due to gate capacitances For applications where no lag is required use blocks from the Physical Signals sublibrary in the Simscape Foundation Library to implement the desired functionality 1 13 1 Getting Started Simulating an Electronic System 1 14 In this section Selecting a Solver on page 1 14
32. conversion Le Cancel Help Apply Configuring the Solver Parameters Configure the solver parameters to use a continuous time solver because SimElectronics models only run with a continuous time solver Increase the maximum step size the solver can take so the simulation runs faster 1 In the model window select Simulation gt Model Configuration Parameters to open the Configuration Parameters dialog box DC Motor Model 2 Select odei5s Stiff NDF from the Solver list 3 Expand Additional options and enter 1 for the Max step size parameter value 4 Click OK Category List Select Solver Data Import Export Optimization Diagnostics Hardware Implementation Model Referencing Simulation Target Code Generation HDL Code Generation Simscape SimMechanics 1G SimMechanics 2G Simulation time Starttime 0 0 Solver options Stoptime 10 0 Type Variable step 7 Solver 4 155 stiff NDF Additional options Max step size 1 Min step size auto Tnitial step size auto Relative tolerance 1 3 Absolute tolerance auto m Shape preservation Disable All Solver reset method Fast n Maximum order 5 Number of consecutive min steps Solver Jacobian method Zero crossing options 1 auto Zero crossing control Use local settings z Algorithm Nonadaptive Time tolerance 10 128 eps Number of consec
33. cts Product Requirements Sim Electronics software is an extension of Simscape product expanding its capabilities to model and simulate electronic and electromechanical elements and devices Sim Electronics software requires these products MATLAB Simulink Simscape Other Related Products The SimElectronics product page at the MathWorks Web site lists the toolboxes and blocksets that extend the capabilities of MATLAB and Simulink These products can enhance your use of SimElectronics software in various applications For more information about MathWorks software products see The online documentation for that product if it is installed The MathWorks Web site at www mathworks com 1 5 1 Getting Started SimElectronics Block Libraries 1 6 In this section Overview of SimElectronics Libraries on page 1 6 Opening SimElectronics Libraries on page 1 6 Overview of SimElectronics Libraries SimElectronics libraries provide blocks for modeling electromechanical and electrical systems within the Simulink environment You can also create custom components either by combining SimElectronics components as Simulink subsystems or by using the Simscape language Note SimElectronics follows the standard Simulink conventions where block inputs and outputs are called ports In SimElectronics each port represents a single electrical terminal A SimElectronics model can contain blocks fro
34. e emission coefficient gt 1 Vt is given by Vt k T e where k is Boltzmann s constant T is the absolute Temperature of the p n junction and e is the magnitude of charge on an electron Settings Main Reverse Breakdown Ohmic Resistance Capacitance Temperature Dependence Diode model Piecewise Linear Zener 5 Forward voltage 0 6 On resistance 20 Ohm h Off conductance 3e 6 5 Apply 2 5 2 Modeling an Electronic System Diode This block represents a diode Use the Diode model parameter to select one of the following model types 1 Piecewise Linear Diode This option invokes the diode model from the Simscape Foundation Library 2 Piecewise Linear Zener Diode i e piecewise linear diode with reverse breakdown characteristics This model is identical to the Piecewise Linear Diode for reverse voltages above the Reverse Breakdown Voltage Vz For voltages below Vz the diode breaks down with a low corresponding Zener Resistance Rz Exponential Diode Uses the standard exponential diode equation I Is exp V N Vt 1 where Is is the Saturation current Vt is the thermal voltage and N is the emission coefficient gt 1 Vt is given by Vt k T e where k is Boltzmann s constant T is the absolute Temperature of the p n junction and e is the magnitude of charge on an electron Settings Main Reverse Breakdown Ohmic Resistance
35. ectrical and the desired solver type For more information see Creating a New Simscape Model You can also use the Creating A New Circuit example under Simscape examples as a template for a new model This example opens a simple electrical model prepopulated with some useful blocks and also opens an Electrical Starter Palette which contains links to the most often used electrical components Open the example by typing ssc new elec the MATLAB Command Window and use File gt Save As to save the example model under the desired name Then delete the unwanted blocks and add new ones from the Electrical Starter Palette and from the block libraries Modeling Instantaneous Events When working with Sim Electronics software your model may include Simulink blocks that create instantaneous changes to the physical system inputs through the Simulink PS Converter block such as those associated with events or discrete sampling When you build this type of model make sure the corresponding zero crossings are generated Many blocks in the Simulink library generate these zero crossings by default For example the Pulse Generator block produces a discrete time output by default and generates the corresponding zero crossings To model instantaneous events select Use local settings or Enable all for the Zero crossing control option under the model s Solver Configuration Parameters to generate zero crossings For more information about zero crossing
36. eters on page 1 20 Configuring the Solver Parameters on page 1 26 Running the Simulation and Analyzing the Results on page 1 27 Overview of DC Motor Example In this example you model a DC motor driven by a constant input signal that approximates a pulse width modulated signal and look at the current and rotational motion at the motor output To see the completed model open the Controlled DC Motor example Selecting Blocks to Represent System Components Select the blocks to represent the input signal the DC motor and the motor output displays The following table describes the role of the blocks that represent the system components Block Description Solver Configuration Defines solver settings that apply to all physical modeling blocks DC Voltage Source Generates a DC signal Controlled PWM Generates the signal that approximates a pulse width Voltage modulated motor input signal H Bridge Drives the DC motor Current Sensor Converts the electrical current that drives the motor into a physical signal proportional to the current 1 Getting Started 1 18 Block Description Ideal Rotational Motion Sensor signal proportional to the motion Converts the rotational motion of the motor into a physical DC Motor Converts input electrical signal into mechanical motion PS Simulink Converts the input physical signal to a Simulink signal Co
37. eters you need to take into account the bias condition that will be used in the circuit This example explains how to do this The Phillips Semiconductors datasheet for a BZX384 B4V3 gives the following data Working voltage Vz V at Iztest 5 mA 4 3 Diode capacitance 450 Reverse current Ig nA at Vp 1V 3 Forward voltage at Ip 5 mA 0 7 In the datasheet the tabulated values for Vy are for higher forward currents This value of 0 7V at 5mA is extracted from the datasheet current voltage curve and is chosen as it matches the zener current used when quoting the working voltage of 4 3V To match the datasheet values the example sets the piecewise linear zener diode block parameters as follows Forward voltage Leave as default value of 0 6V This is a typical value for most diodes and the exact value is not critical However it is important that the value set is taken into account when calculating the On resistance parameter Onresistance This is set using the datasheet information that the forward voltage is 0 7V when the current is 5mA The voltage to be dropped by the On resistance parameter is 0 7V minus the Forward voltage parameter that is 0 1V Hence the On resistance is 0 1V 5mA 20 Q Off conductance This is set using the datasheet information on reverse current The reverse current is 3pA for a reverse voltage of 1V Hence the Off conductance should be set to 3pA 1
38. etwork so use one Solver Configuration block with the default parameter values You must include an Electrical Reference block in each SimElectronics network This block does not have any parameters Input Signal Parameters Generate the sinusoidal control signal using the Sine Wave block Set the Sine Wave block parameters as follows Amplitude 0 5e4 1 4 Frequency pi 5e 4 Triangle Wave Generator Model Sine Wave Output a sine wave O t Amp Sin Freq t Phase Bias Sine type determines the computational technique used The parameters in the two types are related through Samples per period 2 pi Frequency Sample time Number of offset samples Phase Samples per period 2 pi Use the sample based sine type if numerical problems due to running for large times e g overflow in absolute time occur Parameters Sine type Time based Time t Use simulation time z Amplitude 0 5e4 Bias 1e4 Frequency rad sec pi 5e 4 Phase rad 0 Sample time 0 Interpret vector parameters as 1 0 9 cance Apply Triangle Wave Generator Parameters Configure the blocks that model the physical system that generates the triangle wave Integrator Band Limited Op Amp Capacitor and Resistor blocks Noninverting amplifier Band Limited Op Amp1 Resistor2 and Variable Resistor blocks Resistorl Di
39. f the Physical Signal and determines the conversion from the Physical Signal to the unitless Simulink output signal Apply affine conversion check box is only relevant for units with offset such as temperature units Parameters Output signal unit A E Apply affine conversion Torque Display Parameters Specify the parameters of the blocks that create the motor torque display Ideal Rotational Motion Sensor block 1 25 1 Getting Started 1 26 e PS Simulink Converter block Scope block Of the three blocks only the PS Simulink Converter block has parameters you need to configure for this example Set the PS Simulink Converter block Output signal unit parameter to rpm to indicate that the block input signal has units of revolutions per minute Note You must type this parameter value It is not available in the drop down list Ph Block Parameters PS Simulink Converter nl PS Simulink Converter Converts the input Physical Signal to a unitless Simulink output signal The unit expression in Output signal unit parameter must match or be commensurate with the unit of the Physical Signal and determines the conversion from the Physical Signal to the unitless Simulink output signal Apply affine conversion check box is only relevant for units with offset such as temperature units Parameters Output signal unit rpm C Apply affine
40. ff the parameters The BZX384 B4V3 subcircuit can be obtained from Philips Semiconductors http www nxp com models index html The subcircuit data can be used to parameterize the SimElectronics Diode block either in conjunction with the datasheet or on its own For example the Ohmic resistance is defined in the subcircuit as RS 0 387 thus providing the missing piece of information in Example 2 An alternative workflow is to use the SimElectronics Additional Components SPICE Compatible Components sublibrary The SPICE Diode block in this sublibrary can be directly parameterized from the subcircuit by setting Saturation current IS to 1 033e 15 Ohmic resistance RS to 0 387 Emission coefficient ND to 1 001 Zero bias junction capacitance to 2 715e 10 Junction potential VJ to 0 7721 Grading coefficient MG to 0 3557 Capacitance coefficient FC to 0 5 Reverse breakdown current IBV to 0 005 Reverse breakdown voltage BV to 4 3 Note that where there is a one to one correspondence between subcircuit parameters and datasheet values the numbers often differ One reason for this is that datasheet values are sometimes given for maximum values whereas subcircuit values are normally for nominal values In this example the CJO value of 271 5 pF differs from the datasheet capacitance of 450 pF at zero bias for this reason 2 13 2 Modeling an Electronic System 2 14 SPICE Diode This model approx
41. hermal mass of the semiconductor junction respectively The Ideal Heat Flow Source block inputs heat to the model with value equal to the electrically generated heat from the device The two Conductive Heat Transfer blocks model the thermal resistances Resistance R JC conductance 1 R_JC represents the thermal resistance between junction and case Because of this resistance under normal conditions the junction will be hotter than the case Resistance R_CA represents the thermal resistance between port H and the device case If the device has no heatsink then in your model you should connect port H to an Ideal Temperature Source with its temperature set to ambient conditions If your device does have an external heatsink then you must model the heatsink externally to the device and connect the heatsink thermal mass directly to port H If you wish to keep all or part of the thermal model of the device external to the model you can set the necessary block parameters to zero The following rules apply Case thermal mass must be greater than zero Simulating Thermal Effects in Semiconductors Junction thermal mass can only be set to zero if the junction case resistance is also set to zero If both case and junction thermal masses are defined but junction case resistance is zero then the initial temperatures assigned to junction and case must be identical Thermal Mass Parameterization Datasheets usually quote both of the ther
42. imates a SPICE diode You specify both model card and instance parameters as instance parameters on this mask The instance parameter OFF and the noise model parameters KF and AF are not supported Additional instance parameters are SCALE and TOFFSET SCALE is the number of parallel diode instances for this device SCALE multiplies the output current and device charge directly This differs from the AREA parameter which multiples the device parameters IS CJO and IBV and divides RS You can set the diode temperature to a fixed temperature or to the circuit temperature from the SPICE Environment Parameters block plus TOFFSET The block lets you include or exclude capacitance modeling initial conditions and reverse breakdown modeling The capacitance modeling uses the published equations which may yield a slightly different value than SPICE for capacitance The initial condition VO is the voltage across the internal diode junction so it is only effective when junction capacitance is present The breakdown voltage BV is not adjusted as a function of the breakdown current IBV Settings Main Junction Capacitance Reverse Breakdown Temperature Device area AREA a Number of parallel devices SCALE 2 Saturation current IS 1 033e 15 A m 2 Ohmic resistance RS 0 387 m 2 Ohm Emission coefficient ND 1 001 ok cmeer ev Parameterize an Exponential Diode from SPICE Netlis
43. iode with reverse breakdown characteristics This model is identical to the Piecewise Linear Diode for reverse voltages above the Reverse Breakdown Voltage Vz For voltages below Vz the diode breaks down with a low corresponding Zener Resistance Rz Exponential Diode Uses the standard exponential diode equation I Is exp V N Vt 1 where Is is the Saturation current Vt is the thermal voltage and is the emission coefficient gt 1 Vt is given by Vt k T e where k is Boltzmann s constant T is the absolute Temperature of the p n junction and e is the magnitude of charge on an electron Settings Main Reverse Breakdown il Ohmic Resistance Capacitance Temperature Dependence Junction capacitance Fixed or zero junction capacitance Zero bias junction capacitance CJ0 Charge dynamics Do not model charge dynamics ok cmeer ev 2 12 Parameterize an Exponential Diode from SPICE Netlist Parameterize an Exponential Diode from SPICE Netlist If a datasheet does not provide all of the data required by the component model another source is a SPICE netlist for the component Components are defined by a particular type of SPICE netlist called a subcircuit The subcircuit defines the coefficients for the defining equations Most component manufacturers make subcircuits available on their websites The format is ASCII and you can directly read o
44. k to display the triangular output signal Double click the Scope block and then double click the Parameters button 9 to open the Scope parameters dialog box On the History tab clear the Limit data points to last check box Configuring the Solver Parameters Configure the solver parameters to use a continuous time solver because SimElectronics models only run with a continuous time solver You also change the simulation end time tighten the relative tolerance for a more accurate simulation and remove the limit on the number of simulation data points Simulink saves 1 41 1 Getting Started 1 42 4 In the model window select Simulation gt Model Configuration Parameters to open the Configuration Parameters dialog box In the Solver category in the Select tree on the left side of the dialog box Enter 2000e 6 for the Stop time parameter value Select ode23t Mod stiff Trapezoidal from the Solver list Enter 4e 5 for the Max step size parameter value Enter 1e 6 for the Relative tolerance parameter value In the Data Import Export category in the Select tree Clear the Limit data points to last check box Click OK For more information about configuring solver parameters see Simulating an Electronic System on page 1 14 Running the Simulation and Analyzing the Results Run the simulation and plot the results In the model window select Simulation Run to run the simulation To view the triangle
45. lectrical Reference block in each SimElectronics network You must include a Mechanical Rotational Reference block in each network that includes electromechanical blocks These blocks do not have any parameters For more information about using reference blocks see Grounding Rules in the Simscape documentation Motor Input Signal Parameters You generate the motor input signal using three blocks The DC Voltage Source block generates a constant signal The Controlled PWM Voltage block generates a pulse width modulated signal The H Bridge block drives the motor In this example all input ports of the H Bridge block except the PWM port are connected to ground As a result the H Bridge block behaves as follows When the motor is on the H Bridge block connects the motor terminals to the power supply When the motor is off the H Bridge block acts as a freewheeling diode to maintain the motor current In this example you simulate the motor with a constant current whose value is the average value of the PWM signal By using this type of signal you set up a fast simulation that estimates the motor behavior 1 Set the DC Voltage Source block parameters as follows Constant voltage 2 5 1 21 1 Getting Started 1 22 DC Voltage Source The ideal voltage source maintains a constant voltage across its output terminals independent of the current flowing through the source The output voltage is defined by
46. list circuit simulator may be a better option In mechatronic applications in particular you may need to model input output behavior of integrated circuits such as PWM waveform generators and H bridges For these two examples SimElectronics libraries contain abstracted behavior equivalent blocks that you can use Where you need to model other devices possible options include creating your own abstracted model using the Simscape language or using Simulink blocks For an example of using Simulink blocks see the Modeling an Integrated Circuit example When looking for a datasheet make sure you have the originating manufacturer datasheet because some resellers abbreviate them Parameterizing Blocks from Datasheets For additional ways to parameterize and validate your model see Additional Parameterization Workflows on page 2 19 2 Modeling an Electronic System Parameterize a Piecewise Linear Diode Model 2 4 The Triangle Wave Generator example model also described in Triangle Wave Generator Model on page 1 30 contains two zener diodes that regulate the maximum output voltage from an op amp amplifier circuit Each of these diodes is implemented with the SimElectronics Diode block parameterized using the Piecewise Linear Zener option This simple model is sufficient to check correct operation of the circuit and requires fewer parameters than the Exponential option of the Diode block However when specifying the param
47. ltage relationship This results in more efficient simulation but requires some thought to go into the setting of block parameter values An alternative is to use a more complex model that is valid for a wider range of voltage and current values This example uses the Exponential parameterization option of the Diode block This model either requires two data points from the diode current voltage relationship or values for the underlying equation coefficients namely the saturation current IS and the emission coefficient The BZX384 B4V3 datasheet only provides values for the former case Some datasheets do not give the necessary data for either case and you must follow the processes in Example 1 or Example 3 instead The two data points in the table below are from the BZX384 B4V3 datasheet current voltage curve Diode forward voltage 0 7V 1V Diode forward current Ir 5mA 250mA Set the exponential diode block parameters as follows Currents I1 I2 Set to 5 250 mA Voltages V1 V2 Set to 0 7 1 0 V Reverse breakdown voltage BV Set to the datasheet working voltage value 4 3V Ohmic resistance Leave at its default value of 0 01 Q This is an example of a parameter that cannot be determined from the datasheet However setting its value to zero is not necessarily a good 1dea because a small value can help simulation convergence for some circuit topologies The default value has negligible effect a
48. lting current when the gate is in the logic LOW state but the load forces the output voltage to the supply voltage Vcc The default value is 45 mA Propagation delay Time it takes for the output to swing from LOW to HIGH or HIGH to LOW after the input logic levels change For quadratic output it is implemented by the lagged gate input demand The default value is 25 ns Protection diode on resistance The gradient of the voltage current relationship for the protection diodes when forward biased The default value is 5 Q Protection diode forward voltage The voltage above which the protection diode is turned on The default value is 0 6 V The following graphic illustrates the quadratic output model parameterization using the default parameter output characteristics for a 5V supply Selecting the Output Model for Logic Blocks Figure 1 Output HIGH characteristic Output LOW characteristic zl 9 1 4 1 lt 1 14 9 2 23 2 Modeling an Electronic System Simulating Thermal Effects in Semiconductors In this section Using the Thermal Ports on page 2 24 Thermal Model for Semiconductor Blocks on page 2 26 Thermal Mass Parameterization
49. m the standard SimElectronics library from the Simscape Foundation and Utilities libraries or from a custom library you create using the Simscape language based on the Simscape Foundation electrical domain A model can also include blocks from other Simscape add on products as well as Simulink blocks Opening SimElectronics Libraries There are two ways to access SimElectronics blocks Using the Simulink Library Browser to Access the Block Libraries on page 1 6 Using the Command Prompt to Access the Block Libraries on page 1 7 Using the Simulink Library Browser to Access the Block Libraries You can access the blocks through the Simulink Library Browser To display the Library Browser click the Simulink Library button in the toolbar of the MATLAB desktop Alternatively you can type simulink in the MATLAB Command Window Then expand the Simscape entry in the contents tree SimElectronics Block Libraries D Simulink Library Brows lt Enter search term A v 1 2 Simscape SimElectronics Report Generator Robust Control Toolbox a Acmuatoes 4 Drivers Integrated Circuits Passive Devices SimEvents SimRF 4 Simscape Actuators amp Drivers Integrated Circuits Passive Devices Foundation Library SimDriveline Semiceaductar Sensees SimHydraulics SimMechanics Semiconductor Sensors Devices SimPower Systems Utilities E i Adtitional Simulink 3D Anim
50. mal resistances but rarely give values for thermal masses There are two parameterization options for the thermal masses By thermal time constants Parameterize the thermal masses in terms of thermal time constants This is the default By thermal mass Specify the thermal mass values directly The thermal time constants J and t_C are defined as follows tJ MJ R JC t C MC RCA where M J and M C are the junction and case thermal masses respectively R_JC is the thermal resistance between junction and case and CA is the thermal resistance between port H and the device case You can determine the case time constant by experimental measurement If data is not available for the junction time constant you can either omit it and set the junction case resistance to zero or you can set the junction time constant to a typical value of one tenth of the case time constant The alternative is to estimate thermal masses based on device dimensions and averaged material specific heats Electrical Behavior Depending on Temperature For blocks with optional thermal ports there are two simulation options Simulate the generated heat device temperature and the effect of temperature on the electrical equations Simulate the generated heat and device temperature but do not include effect of temperature on the electrical equations Use this option when the impact of temperature on the electrical equations is small over the temperature
51. nd f is the 3dB bandwidth The input current is given by Vp Vm Rin where Rin is the input resistance The no load output voltage is limited the range Vmin to Vmax and the slew rate is limited to Vdot The Initial output voltage VO sets the initial op amp output voltage Note that this does not take account of any voltage drop across Rout The initial condition is not used if you select the Start simulation from steady state option in the Solver Configuration block Settings Parameters Gain A 7 1e4 Input resistance Rin 39e6 Ohm Y Output resistance Rout 0 Ohm Minimum output Vmin 20 v Maximum output Vmax 20 Y Maximum slew rate Vdot 1 25 1e 6 V s Bandwidth f 4e6 Hz Initial output voltage VO 0 Apply Set the two Diode block parameters for a 4 3V zener diode To model a BZX384 B4V3 set block parameters as follows the Main tab set Diode model to Piecewise Linear Zener This selects a simplified zener diode model that is more than adequate to test the correct operation of this circuit Leave the Forward voltage as 0 6V this is a typical value for most diodes The datatsheet gives the forward current as 250mA when the forward voltage is 1V So that the Diode block matches this set the On resistance to 1V 0 6V 250mA 1 6 ohms The datatsheet gives the reverse leakage current as at a reverse voltage of 1V Therefore set the Off conductance t
52. nent For an example of parameter tuning see the example Solar Cell Parameter Extraction From Data Building an Equivalent Model of a SPICE Netlist In Example 3 parameterization from a SPICE netlist is relatively straightforward because the netlist defines a single device the diode plus corresponding model card the parameters Conversely a netlist for an op amp may have more than ten devices plus supporting model cards In principle it is possible to build your own equivalent model of a more complex device by making use of the SPICE Compatible Components sublibrary and connecting them together using the information in the netlist Before embarking on this you should ensure that the SPICE Compatible Components sublibrary has all of the component models that you need If the device models you wish to model are complex hundreds of components then cosimulation with an external circuit simulator may be a better approach 2 19 2 Modeling an Electronic System Selecting the Output Model for Logic Blocks In this section Available Output Models on page 2 20 Quadratic Model Output and Parameters on page 2 21 Available Output Models The blocks in the Logic sublibrary of the Integrated Circuits library provide a choice of two output models Linear Models the gate output as a voltage source driving a series resistor and capacitor connected to ground This is suitable for logic circuit operation under
53. nverter Scope Displays motor current and rotational motion Electrical Reference Provides the electrical ground Mechanical Rotational Reference Provides the mechanical ground Building the Model Create a Simulink model add blocks to the model and connect the blocks 1 2 Create a new model Add to the model the blocks listed in the following table The Library column of the table specifies the hierarchical path to each block Drivers gt Rotational Actuators Block Library Path Quantity Solver Simscape gt Utilities 1 Configuration DC Voltage Simscape gt Foundation Library gt Electrical 1 Source gt Electrical Sources Controlled PWM Simscape gt SimElectronics gt Actuators amp 1 Voltage Drivers gt Drivers H Bridge Simscape gt SimElectronics gt Actuators amp 1 Drivers gt Drivers Current Sensor Simscape gt Foundation Library gt Electrical 1 gt Electrical Sensors Ideal Rotational Simscape gt Foundation Library gt 1 Motion Sensor Mechanical gt Mechanical Sensors DC Motor Simscape gt SimElectronics gt Actuators amp 1 DC Motor Model Block Library Path Quantity PS Simulink Simscape gt Utilities 2 Converter Scope Simulink gt Commonly Used Blocks 2 Electrical Simscape gt Foundation Library gt Electrical 1 Reference gt Electrical Elements Mechanical Simscape gt Foundation Libra
54. o 3pA 1V 3e 6 S 1 37 1 Getting Started 1 38 The datatsheet gives the reverse voltage as 4 3V On the Reverse Breakdown tab set the Reverse breakdown voltage Vz to 4 3 V Set the Zener resistance Rz to a suitably small number The datatsheet quotes the zener voltage for a reverse current of 5mA For the Diode block to be representative of the real device the simulated reverse voltage should be close to 4 3V at 5mA As Rz tends to zero the reverse breakdown voltage will tend to Vz regardless of current as the voltage current gradient becomes infinite However for good numerical properties Rz must not be made too small If say you allow a 0 01V error on the zener voltage at 5mA then Rz will be 0 01V 5mA 2 ohms Set the Zener resistance Rz parameter to this value Diode This block represents a diode Use the Diode model parameter to select one of the following model types 1 Piecewise Linear Diode This option invokes the diode model from the Simscape Foundation Library 2 Piecewise Linear Zener Diode i e piecewise linear diode with reverse breakdown characteristics This model is identical to the Piecewise Linear Diode for reverse voltages above the Reverse Breakdown Voltage Vz For voltages below Vz the diode breaks down with a low corresponding Zener Resistance Rz 3 Exponential Diode Uses the standard exponential diode equation I Is exp V N Vt 1 where Is is the Saturation current Vt is the thermal v
55. ode and Diodel 1 35 1 Getting Started Simulink PS Converter and PS Simulink Converter blocks that bridge the physical part of the model and the Simulink part of the model 1 Accept the default parameters for the Simulink PS Converter block These parameters establish the units of the physical signal at the block output such that they match the expected default units of the Variable Resistor block input 2 Set the two Band Limited Op Amp block parameters for the LM7301 device with a 20V power supply The datatsheet gives the gain as 97dB which is equivalent to 10 97 20 7 1 4 Set the Gain A parameter to 71e4 The datatsheet gives input resistance as 39Mohms Set Input resistance Rin to 39e6 Set Output resistance Rout to 0 ohms The datatsheet does not quote a value for Rout but the term is insignificant compared to the output resistor that it drives Set minimum and maximum output voltages to 20 and 20 volts respectively The datatsheet gives the maximum slew rate as 1 25V ps Set the Maximum slew rate Vdot parameter to 1 25e6 V s 1 36 Triangle Wave Generator Model Band Limited Op Amp This block models a band limited op amp If the voltages at the positive and negative pins are denoted Vp and Vm then the output voltage is given by Vout A Vp Vm 1 s 2 pi f 1 Iout Rout where A is the gain Rout is the output resistance Iout is the output current s is the Laplace operator a
56. oltage and N is the emission coefficient gt 1 Vt is given by Vt k T e where k is Boltzmann s constant T is the absolute Temperature of the p n junction and e is the magnitude of charge on an electron Settings Main Reverse Breakdown Ohmic Resistance Capacitance Temperature Dependence Diode model Piecewise Linear Zener M Forward voltage 0 6 X On resistance 20 Ohm ha Off conductance 3e 6 5 M Triangle Wave Generator Model Diode This block represents a diode Use the Diode model parameter to select one of the following model types 1 Piecewise Linear Diode This option invokes the diode model from the Simscape Foundation Library 2 Piecewise Linear Zener Diode i e piecewise linear diode with reverse breakdown characteristics This model is identical to the Piecewise Linear Diode for reverse voltages above the Reverse Breakdown Voltage Vz For voltages below Vz the diode breaks down with a low corresponding Zener Resistance Rz Exponential Diode Uses the standard exponential diode equation I Is exp V N Vt 1 where Is is the Saturation current Vt is the thermal voltage and N is the emission coefficient gt 1 Vt is given by Vt k T e where k is Boltzmann s constant T is the absolute Temperature of the p n junction and e is the magnitude of charge on an electron Settings Main Reverse Breakdown Ohmic Resistance Capacitance Temperature
57. on page 2 27 Electrical Behavior Depending on Temperature on page 2 27 Improving Numerical Performance on page 2 28 Using the Thermal Ports Certain SimElectronics blocks for example the blocks in the Semiconductors library contain an optional thermal port This port is hidden by default If you want to simulate the generated heat and device temperature expose the thermal port on a particular block instance in your block diagram 1 Right click the block where you want to show the thermal port 2 From the context menu select Simscape gt Block choices gt Show thermal port Simscape Log simulation data Explore Block choices v No thermal port dai v Show thermal port 15 Cut Ctrl X E Z N data H a pon a Ha Ctrl C Paste Ctrl V When the thermal port is exposed the block dialog box contains an additional tab Thermal Port For semiconductor devices the tab always contains the same set of parameters 2 24 Simulating Thermal Effects in Semiconductors Parameters Main Ohmic Resistance Junction Capacitance Temperature Dependence Thermal Port Junction case and case ambient or case heatsink thermal 010 K W resistances R_JC R_CA Thermal mass parameterization thermal time constants 7 Junction and case thermal time constants t J t C E9101 xs M Junction and case initial 2525 temperatures T_J T_C
58. ral government or other entity acquiring for or through the federal government and shall supersede any conflicting contractual terms or conditions If this License fails to meet the government s needs or is inconsistent in any respect with federal procurement law the government agrees to return the Program and Documentation unused to The MathWorks Inc Trademarks MATLAB and Simulink are registered trademarks of The MathWorks Inc See www mathworks com trademarks for a list of additional trademarks Other product or brand names may be trademarks or registered trademarks of their respective holders Patents MathWorks products are protected by one or more U S patents Please see www mathworks com patents for more information Revision History April 2008 October 2008 March 2009 September 2009 March 2010 September 2010 April 2011 September 2011 March 2012 September 2012 March 2013 September 2013 March 2014 October 2014 March 2015 September 2015 Online only Online only Online only Online only Online only Online only Online only Online only Online only Online only Online only Online only Online only Online only Online only Online only New for Version 1 0 Release 2008a Revised for Version 1 1 Release 2008b Revised for Version 1 2 Release 2009a Revised for Version 1 3 Release 2009b Revised for Version 1 4 Release 2010a Revised for Version 1 5 Release 2010b Revised for Version 1 6 Release 2011a
59. rameter is only visible when you select By thermal mass for the Thermal mass parameterization parameter The default valueis 01 J K Junction and case initial temperatures T J T C A row vector T J T C of two temperature values The first value T J is the junction initial temperature The second value C is the case initial temperature The default value is 25 25 C For more information on selecting the parameter values see Thermal Model for Semiconductor Blocks on page 2 26 and Improving Numerical Performance 2 25 2 Modeling an Electronic System 2 26 on page 2 28 For explanation of the relationship between the Thermal Port and Temperature Dependence tabs in a block dialog box see Electrical Behavior Depending on Temperature on page 2 27 Thermal Model for Semiconductor Blocks All blocks with optional thermal ports include an internal thermal model with thermal masses and resistances The purpose of including this model internally is to keep your diagram uncluttered by the thermal model The following figure shows an equivalent model of the internal thermal model for semiconductor devices 1R CA Conductive Hest Transfer VR JC Conductive Hest Transfer Case Thermal Mass Ideal Heat Flow Source Ther mal Reference The port H in the diagram corresponds to the thermal port H of the block The two Thermal Mass blocks represent the thermal mass of the device case and the t
60. rify that it works the way you expected Then incrementally make your model more realistic factoring in effects such as motor shaft compliance hard stops and the other things that describe real world phenomena Simulate and test your model at every incremental step Use subsystems to capture the model hierarchy and simulate and test your subsystems separately before testing the whole model configuration This approach helps you keep your models well organized and makes it easier to troubleshoot them Required Blocks Each topologically distinct physical network in a diagram requires exactly one Solver Configuration block found in the Simscape Utilities library The Solver Configuration block specifies global environment information for simulation and provides parameters for the solver that your model needs before you can begin simulation For more information see the Solver Configuration block reference page Each electrical network requires an Electrical Reference block This block establishes the electrical ground for the circuit Networks with electromechanical blocks also require 1 11 1 Getting Started 1 12 a Mechanical Rotational Reference block For more information about using reference blocks see Grounding Rules in the Simscape documentation Creating a New Model An easy way to start a new SimElectronics model prepopulated with the required blocks is to use the Simscape function 55 new with a domain type of el
61. rough variable such as current or torque transferred along the Physical connection line is divided among the multiple components connected by the branches How the Through variable is divided is determined by the system dynamics For each Through variable the sum of all its values flowing into a branch point equals the sum of all its values flowing out You can connect Physical Signal ports to other Physical Signal ports with regular connection lines similar to Simulink signal connections These connection lines carry physical signals between SimElectronics blocks You can connect Physical Signal ports to Simulink ports through special converter blocks Use the Simulink PS Converter block to connect Simulink outports to Physical Signal inports Use the PS Simulink Converter block to connect Physical Signal outports to Simulink inports Unlike Simulink signals which are essentially unitless Physical Signals can have units associated with them SimElectronics block dialogs let you specify the units along with the parameter values where appropriate Use the converter blocks to associate units with an input signal and to specify the desired output signal units For examples of applying these rules when creating an actual electromechanical model see DC Motor Model on page 1 17 MathWorks recommends that you build simulate and test your model incrementally Start with an idealized simplified model of your system simulate it ve
62. rts the output physical signal to a Simulink signal Scope Displays the triangular output wave Band Limited Op Amp Diode Limit the output of the Band Limited Op Amp block to make Works with the capacitor and resistor to create an integrator and a noninverting amplifier the output waveform independent of supply voltage 1 31 1 Getting Started Building the Model Create a Simulink model add blocks to the model and connect the blocks 1 Create a new model 2 Add to the model the blocks listed in the following table The Library Path column of the table specifies the hierarchical path to each block Block Library Path Quantity Sine Wave Simulink gt Sources 1 Simulink PS Simscape gt Utilities 1 Converter Solver Simscape gt Utilities 1 Configuration Electrical Simscape gt Foundation Library gt 1 Reference Electrical gt Electrical Elements Capacitor Simscape gt Foundation Library gt 1 Electrical gt Electrical Elements Resistor Simscape gt Foundation Library gt 3 Electrical gt Electrical Elements Variable Resistor Simscape gt Foundation Library gt 1 Electrical gt Electrical Elements DC Voltage Simscape gt Foundation Library gt 1 Source Electrical gt Electrical Sources Voltage Sensor Simscape gt Foundation Library gt 1 Electrical gt Electrical Sensors PS Simulink Simscape gt Utilities 1 Converter
63. ry gt 1 Rotational Mechanical gt Rotational Elements Reference Note You can use the Simscape function ssc_new with a domain type of electrical to create a Simscape model that contains the following blocks Simulink PS Converter PS Simulink Converter Scope Solver Configuration Electrical Reference This function also selects the Simulink ode15s solver Connect the blocks as shown in the following figure 1 Getting Started 1 20 Solver Configurstion PS Simulink Converter Scope Mechanical 7 Rotational Reference Now you are ready to specify block parameters Specifying Model Parameters Specify the following parameters to represent the behavior of the system components Model Setup Parameters on page 1 20 Motor Input Signal Parameters on page 1 21 Motor Parameters on page 1 24 Current Display Parameters on page 1 25 Torque Display Parameters on page 1 25 Model Setup Parameters The following blocks specify model information that is not specific to a particular block Solver Configuration Electrical Reference Mechanical Rotational Reference As with Simscape models you must include a Solver Configuration block in each topologically distinct physical network This example has a single physical network so use one Solver Configuration block with the default parameter values DC Motor Model You must include an E
64. s You can connect Simulink blocks through the Simulink PS Converter and PS Simulink Converter blocks from the Simscape Utilities library These blocks convert electrical signals to and from Simulink mathematical signals The rules that you must follow when building an electronic or electromechanical model are described in Basic Principles of Modeling Physical Networks in the Simscape documentation This section briefly reviews these rules SimElectronics blocks in general feature Conserving ports El and Physical Signal inports and outports D There are two main types of Physical Conserving ports used in SimElectronics blocks electrical and mechanical rotational Each type has specific Through and Across variables associated with it You can connect Conserving ports only to other Conserving ports of the same type The Physical connection lines that connect Conserving ports together are nondirectional lines that carry physical variables Across and Through variables as described above rather than signals You cannot connect Physical lines to Simulink ports or to Physical Signal ports Two directly connected Conserving ports must have the same values for all their Across variables such as voltage or angular velocity You can branch Physical connection lines When you do so components directly connected with one another continue to share the same Across variables Any Essential Electronic Modeling Techniques Th
65. source maintains a constant voltage across its output terminals independent of the current flowing through the source The output voltage is defined by the Constant voltage parameter and can be any real value Source code Settings Parameters Constant voltage 8 Set the Resistor block parameters as follows Resistance 10000 Triangle Wave Generator Model gt Block Parameters Resistor x Resistor The voltage current V I relationship for a linear resistor is V I R where R is the constant resistance in ohms The positive and negative terminals of the resistor are denoted by the and signs respectively By convention the voltage across the resistor is given by V V and the sign of the current is positive when flowing through the device from the positive to the negative terminal This convention ensures that the power absorbed by a resistor is always positive Source code Settings Parameters Variables Resistance 10000 Ohm 9 Set the Resistor1 block parameters as follows Resistance 1000 10 Set the Resistor2 block parameters as follows Resistance 10000 11 Accept the default parameters for the PS Simulink Converter block These parameters establish the units of the physical signal at the block output such that they match the expected default units of the Scope block input Signal Display Parameters Specify the parameters of the Scope bloc
66. t SPICE Diode This model approximates a SPICE diode You specify both model card and instance parameters as instance parameters on this mask The instance parameter OFF and the noise model parameters KF and AF are not supported Additional instance parameters are SCALE and TOFFSET SCALE is the number of parallel diode instances for this device SCALE multiplies the output current and device charge directly This differs from the AREA parameter which multiples the device parameters IS CJO and IBV and divides RS You can set the diode temperature to a fixed temperature or to the circuit temperature from the SPICE Environment Parameters block plus TOFFSET The block lets you include or exclude capacitance modeling initial conditions and reverse breakdown modeling The capacitance modeling uses the published equations which may yield a slightly different value than SPICE for capacitance The initial condition VO is the voltage across the internal diode junction so it is only effective when junction capacitance is present The breakdown voltage BV is not adjusted as a function of the breakdown current IBV Settings Main Junction Capacitance Reverse Breakdown Temperature Model junction capacitance Yes Zero bias junction capacitance CIO 2 715e 10 Junction potential VJ 0 7721 Grading coefficient MG 0 3557 Capacitance coefficient FC 0 5 Transit time TT 0
67. t the working current of 5mA the additional voltage drop being 5e 3 times 0 01 5e 5V Physically this term will not be zero because of the connection resistances Zero bias junction capacitance Set to the datasheet diode capacitance value 450 pF A more complex capacitance model is also available for the Diode component with the exponential equation option However the datasheet does not provide the necessary data Moreover the operation of this circuit is not sufficiently sensitive to voltage dependent capacitance effects to warrant the extra detail Parameterize an Exponential Diode from a Datasheet Diode This block represents a diode Use the Diode model parameter to select one of the following model types 1 Piecewise Linear Diode This option invokes the diode model from the Simscape Foundation Library 2 Piecewise Linear Zener Diode i e piecewise linear diode with reverse breakdown characteristics This model is identical to the Piecewise Linear Diode for reverse voltages above the Reverse Breakdown Voltage Vz For voltages below Vz the diode breaks down with a low corresponding Zener Resistance Rz Exponential Diode Uses the standard exponential diode equation I Is exp V N Vt 1 where Is is the Saturation current Vt is the thermal voltage and is the emission coefficient gt 1 Vt is given by Vt k T e where k is Boltzmann s constant T is the absolute Temperature of the p n junction
68. the 10009 load seen by the op amp Minimum output Vmin set to the negative supply voltage 20V in this model Maximum output Vmax set to the positive supply voltage 20V in this model Maximum slew rate Vdot set to 1 25 1e 6 V s Bandwidth f set to 4e6 Hz Note that these parameters correspond to the values for 5 volt operation The datasheet also gives values for 2 2V and 30V operation It is usually better to pick 2 17 2 Modeling an Electronic System 2 18 values for a supply voltage below what your circuit uses because performance is worse at lower voltages for example the gain is less and the input impedance is less You can use the variation in op amp parameters with supply voltage to suggest a typical range of parameter values for which you should check the operation of your circuit Ph BI ock Parameters Band Lin Op Amp Taran Band Limited Op Amp This block models a band limited op amp If the voltages at the positive and negative pins are denoted Vp and Vm then the output voltage is given by Vout A Vp Vm 1 s 2 pi f 1 Iout Rout where A is the gain Rout is the output resistance Iout is the output current s is the Laplace operator and f is the 3dB bandwidth The input current is given by Vp Vm Rin where Rin is the input resistance The no load output voltage is limited the range Vmin to Vmax and the slew rate is limited to Vdot The Initial output voltage VO sets the initial op amp o
69. the Constant voltage parameter and can be any real value Source code Settings Parameters Constant voltage 2 5 X Apply 2 Setthe Controlled PWM Voltage block parameters as follows PWM frequency 4000 Simulation mode Averaged This value tells the block to generate an output signal whose value is the average value of the PWM signal Simulating the motor with an averaged signal estimates the motor behavior in the presence of a PWM signal To validate this approximation use value of PWM for this parameter DC Motor Model Wn Parameter s Con trolled PWM Voltage es Controlled PWM Voltage This block represents a Pulse Width Modulated PWM voltage source across its PWM and REF ports that depends on the reference voltage Vref across its ref and ref ports The duty cycle in percent is given by 100 Vref Vmin Vmax Vmin where Vmin and Vmax are the minimum and maximum values for Vref The output voltage is zero when the pulse is low and is set equal to the Output voltage amplitude parameter when high At time zero the pulse is initialized as high unless the duty cycle is set to zero or the Pulse delay time is greater than zero The Simulation mode can be set to PWM or Averaged In PWM mode the output is a PWM signal In Averaged mode the output is constant with value equal to the averaged PWM signal Settings Parameters PWM frequency 4000 Hz M Input value Vmin
70. ther MathWorks product SimPowerSystems software is better suited for power system networks where The underlying equations are predominantly linear e g transmission lines and linear machine models Three phase motors and generators are used SimPowerSystems has blocks and solvers specifically designed for these types of applications 1 Getting Started Modeling Physical Networks with SimElectronics Blocks 1 4 SimElectronics is part of the Simulink Physical Modeling family Models using Sim Electronics are essentially Simscape block diagrams To build a system level model with electrical blocks use a combination of SimElectronics blocks and other Simscape and Simulink blocks You can connect SimElectronics blocks directly to Simscape blocks You can connect Simulink blocks through the Simulink PS Converter and PS Simulink Converter blocks from the Simscape Utilities library These blocks convert electrical signals to and from Simulink mathematical signals For more information about connecting different types of blocks see Connector Ports and Connection Lines and Connecting Simscape Diagrams to Simulink Sources and Scopes in the Simscape documentation For more information about basic principles to follow when building an electrical model with SimElectronics see Basic Principles of Modeling Physical Networks in the Simscape documentation Required and Related Products Required and Related Produ
71. tly from industry data sheets Semiconductor and motor models with temperature dependent behavior and configurable thermal ports deal and nonideal model variants enabling adjustment of model fidelity Ability to extend component libraries using the Simscape language Access to linearization and steady state calculation capabilities in Simscape Support for C code generation SimElectronics Assumptions and Limitations SimElectronics Assumptions and Limitations SimElectronics contains blocks that let you model electronic and mechatronic systems at a speed and level of fidelity that is appropriate for system level analysis The blocks let you perform tradeoff analyses to optimize system design for example by testing various algorithms with different circuit implementations The library contains blocks that use either high level or more detailed models to simulate components SimElectronics does not have the capability to Model large circuits with dozens of analog components such as a complete transceiver Perform either layout physical design tasks or the associated implementation tasks such as layout versus schematic LVS design rule checking DRC parasitic extraction and back annotation Model 3 D parasitic effects that are typically important for high frequency applications For these types of requirements you must use an EDA package specifically designed for the implementation of analog circuits Ano
72. tor parameters are defined The default value is 25 C Parameters Electrical Torque Mechanical Temperature Dependence Thermal Port Thermal mass 100 J K Initial temperature 25 Y Thermal mass Thermal mass of the electrical winding defined as the energy required to raise the temperature by one degree The default value is 100 J K Initial temperature The temperature of the thermal port at the start of simulation The default value is 25 C For more information on selecting the parameter values see Thermal Model for Actuator Blocks on page 2 31 Parameters for actuator blocks with two windings differ and are described on the respective block reference pages Simulating Thermal Effects in Rotational and Translational Actuators Thermal Model for Actuator Blocks The following illustration shows the thermal port model used by the actuator blocks The heat generated by the copper windings is provided as an input to the S physical signal input port of the Ideal Heat Flow Source The thermal mass represents the lumped thermal mass of the copper winding where thermal mass is defined as the energy required to raise its temperature by one degree If the mass is denoted M and the specific heat capacity is then thermal mass is ea Flow Thermal Mass iE Source Thermal Reference Winding resistance is assumed linearly dependent on temperature and is given by R
73. utive zero crossings Tasking and sample time options Tasking mode for periodic sample times E Automatically handle rate transition for data transfer Signal threshold auto 1000 Auto Lek For more information about configuring solver parameters see Simulating an Electronic System on page 1 14 Running the Simulation and Analyzing the Results In this part of the example you run the simulation and plot the results In the model window select Simulation gt Run to run the simulation To view the motor current and torque in the Scope windows double click the Scope blocks You can do this before or after you run the simulation 1 27 1 Getting Started 1 28 Note By default the scope displays appear stacked on top of each other on the screen so you can only see one of them Click and drag the windows to reposition them The following plot shows the motor current Esos ke Motor Current The next plot shows the motor rpm DC Motor Model Motor RPM As expected the motor runs at about 2000 rpm when the applied DC voltage is 2 5 V 1 29 1 Getting Started Triangle Wave Generator Model 1 30 In this section Overview of Triangle Wave Generator Example on page 1 30 Selecting Blocks to Represent System Components on page 1 30 Building the Model on page 1 3
74. utput voltage Note that this does not take account of any voltage drop across Rout The initial condition is not used if you select the Start simulation from steady state option in the Solver Configuration block Settings Parameters Gain A 7 1e4 Input resistance Rin 39e6 Ohm ka Output resistance Rout 0 Ohm Minimum output Vmin 20 v Maximum output Vmax 20 Maximum slew rate Vdot 1 25 1e 6 V s X Bandwidth f 4e6 Hz X Initial output voltage V0 0 2 Additional Parameterization Workflows Additional Parameterization Workflows There are several other ways to parameterize and validate your model In this section Validation Using Data from SPICE Tool on page 2 19 Parameter Tuning Against External Data on page 2 19 Building an Equivalent Model of a SPICE Netlist on page 2 19 Validation Using Data from SPICE Tool One way to validate a parameterized SimElectronics component is to compare its behavior to data from specialist circuit simulation tool that uses a manufacturer SPICE netlist of the device If doing this it is important to create a test harness for the component that exercises it over the relevant operating points and frequencies Parameter Tuning Against External Data If you have lab measurements of the device or data from another simulation environment you can use this to tune the parameters of the equivalent SimElectronics compo
75. you can apply to any SimElectronics model to overcome simulation issues Add parasitic capacitors and or resistors specifically junction capacitance and ohmic resistance to the circuit to avoid numerical issues The Astable Oscillator example uses these devices Adjust the current and voltage sources so they start at zero and ramp up to their final values rather than starting at nonzero values Modeling Instantaneous Events on page 1 12 and Using Simulink Blocks to Model Physical Components on page 1 12 describe how to avoid simulation errors in the presence of specific SimElectronics model configurations 1 15 1 Getting Started 1 16 Running a Time Domain Simulation When you run a time domain simulation SimElectronics software uses the Simscape solver to analyze the physical system in the Simulink environment For more information see How Simscape Simulation Works in the Simscape documentation Running a Small Signal Frequency Domain Analysis You can perform small signal analysis for Simscape and SimElectronics models using linearization capabilities of Simulink software For more information see Linearize an Electronic Circuit in the Simscape documentation DC Motor Model DC Motor Model In this section Overview of DC Motor Example on page 1 17 Selecting Blocks to Represent System Components on page 1 17 Building the Model on page 1 18 Specifying Model Param

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