Photon Testreport Fronius IG TL 5.0
Contents
1. beginning with the highest values and decreasing to the lowest possible values the IG TL 5 0 reaches a consistent adjustment efficien cy of above 99 percent Overall efficiency The MPP tracker s consistent operation with decreasing DC power results in an overall efficiency path that is almost identi cal to that of conversion efficiency though at a slightly lower level 158 V MPP in V 100 110 120 10 20 30 40 50 60 70 80 90 387 i O 368 an a 350 10 20 30 40 50 aac ae Paps 10 20 30 40 50 60 70 80 90 100 Nominal power Ppp A ee KKK N W 35 10 20 30 40 7 60 7 z mm 110 120 Nominal on Pups sr EI 120 110 120 10 20 30 40 50 60 70 80 90 100 110 120 0 2 4 1 000 700 663 645 IHH 626 1H 608 589 571 553 534 516 497 419 461 4 A 442 424 405 387 368 35 0 70 75 80 85 90 95100 n in Nsum in 0 70 75 80 85 90 95100 N 0 Photon International September 2010 10 20 30 40 50 60 Nominal power P pp present mode shows the following values fed in power grid voltage output current grid frequency and generator voltage and current Using a Fronius Sensor Box users can also access data on module temperature ambient tempe2. ages show the inverter from above while operating at nominal power at an ambient temperature of 26 C However the unit s multi level construction makes it impossi ble to measure the temperatures for all com ponents Component temperatures as high as 62 8 C were seen on the circuit board These values arent exactly low but within reasonable limits for power electronics The temperature of the electrolytic capacitors in the power element is in a safe range Summary The Fronius IG TL 5 0 is clearly arranged and appears simple to manufacture The system employed with the wall bracket and power connections is unusual and as with most unconventional solutions it remains to be seen whether it will prove itself in practice The maximum conversion efficiency of 98 percent is a very high value but only occurs at the lowest possible voltages The device reaches its highest conversion efficiency at MPP voltages of between 350 and 424 V that is when the buck converter which functions as a DC DC converter is bypassed by a relay At low powers the conversion ef ficiency drops by 5 to 8 percentage points at higher MPP voltages it drops by up to 2 1 percentage points The European efficiency deviates from the maximum conversion efficiency by 0 6 percentage points Thanks to its very consis tent and high MPPT adjustment efficiency the graph for overall efficiency is almost identical to that of conversion efficiency The MPP
3. nominal power was about one MPPT adjustment efficiency The MPPT adjustment efficiency is consistent and high over the entire operating range if measured when power is set to decrease A slight exception is recorded at low powers and MPP voltages due to the buck convert er Otherwise the inverter s MPP power is consistently above 99 percent of available power If power is set to increase the MPPT ad justment efficiency is somewhat less con sistent It drops at low powers when the buck converter comes into play as well as at higher voltages Otherwise the values are consistently above 99 percent here too Overall efficiency The area of maxi mum overall efficiency is found at low MPP voltages The vertical line at 60 percent of nominal power and the horizontal line at an MPP voltage of 350 V so at the lower edge of the MPP voltage range meet at the maximum overall efficiency of 98 percent Weighted conversion efficiency Euro Photon International September 2010 science amp technology inverters test pean efficiency reaches its peak at low MPP voltages At 97 4 percent it exceeded the manufacturer s specifications of 97 3 per cent The difference between the maximum conversion efficiency and maximum Euro pean efficiency is just 0 6 percentage points Californian efficiency reaches its peak at 97 5 percent with the highest values also occurring at low MPP voltages The diagram clearly shows that efficie
4. voltage range of 350 to 700 V specified by the manufacturer is not quite far enough removed from the inverter s maximum DC voltage of 850 V Assuming a fill factor of 75 percent it can be exploited up to 680 V for crystalline modules and 629 V for thin film modules If decreasing DC power is simulated the PHOTON efficiency for medium irradiation is very high at 95 9 percent The difference of around 2 1 percentage points between the maximum conversion efficiency and PHO TON efficiency reflects the rather consider able dependence on voltage and power The PHOTON efficiency for high irradiation is slightly higher at 96 2 percent If increasing DC power is simulated the MPPT adjustment efficiency drops at low powers As a result the PHOTON efficiency at medium irradiation decreases slightly to 95 7 percent The manufacturer states that it is currently analyzing this situation see box p 162 The PHOTON efficiency for high irradiation with increasing DC power was identical to the value seen with decreas ing power When selecting the PV system s MPP the lower third of the MPP voltage range should be chosen Overall efficiency also reaches its peak in this range The IG TL 5 0 has a large overload range of 110 9 percent The inverter s output pow er display is accurate over the entire power range The efficiency s dependence on tempera ture is low at 0 4 percentage points and the usable ambient temperature range is f
5. A subsequent automatic disconnection unit made of four AC output relays two connected in series for both the neutral and live wires separates the inverter from the grid in the event that grid voltage grid frequency or grid impedance deviate from designated limits The same applies in the event that residual current is measured on the DC side or grid side An output filter installed by the grid clamp eliminates any radio interference Measurements All of the following measurements are based on a grid voltage of 230 V The IG TL 5 0 s maximum DC voltage is 850 V and the DC nominal power is 4 730 W At most the inverter can accept a generator power of 5 250 W Depending on whether the DC power is preset to increase or decease the device displays different behavior in terms of MPP tracking The differences are small but sig nificant and also have an impact on the PHOTON efficiency Therefore both cases are documented in this overview Locating the MPP At the start of the measurements the DC and AC sides were switched off At a predetermined IV curve with nominal power and an MPP voltage of 515 V the inverter needs about 52 seconds to connect to the grid and then another 53 seconds to reach its MPP When switching from 515 V to 497 V the device needs about 61 seconds while switching to the next higher MPP voltage of 533 V takes about 77 seconds MPP range The MPP range stretches from 350 to 700 V which is a wide r
6. airly wide at 20 to 55 C so there is no need to take power reductions into account This light easy to operate inverter with a good PHOTON efficiency is a great addition to Fronius product line It takes its place in the top fourth of the inverters that PHOTON Lab has tested thus far It is suited for use with all module types even thin films that don t need to be grounded The company is planning to obtain the corresponding ap provals from module manufacturers for its product Text Heinz Neuenstein Jochen Siemer Further information Contacts page 264 Photon International September 2010
7. al signals or installation relays Operation The device arrives at the customer s home well packaged and protected in two Styro foam molds Mounting the wall bracket which contains the connection area and in serting the power element is simple enough At 19 1 kg the IG TL 5 0 is rather light As long as the solar generator is properly designed and the internal DC disconnect is switched on the inverter can begin opera tion It took about 52 seconds to run a series of tests before connecting to the grid The display is level with the front cover has orange backlighting and is easy to read The menu language is available in German or English and the addition of other lan guages is planned The display is activated as soon as grid voltage is present and turns off if the device isn t used for 2 minutes In the set up menu users have the option of setting the display lighting to turn on or off for extended periods of time The unit s four buttons can be used to set a variety of parameters The display offers access to a lot of data and is clearly structured In addition to various status and error messages the unit s 197 science amp technology inverters test Conversion efficiency The IG TL 5 0 reaches its highest value at lower MPP voltages beyond around 424 V the buck converter is activated resulting in losses in efficiency x MPPT adjustment efficiency decreasing power At different input powers
8. ange The distance between the upper limit and the unit s maximum DC voltage of 850 V is not quite adequate enough Conversion efficiency The inverter can operate with 110 percent of its nominal power in an MPP voltage range of 350 to 700 V Therefore efficiency was calculated for this area A small area in the diagram with hatching going from the bottom left to the top right represents limitations on the MPP voltage range when the device is used with crystal line modules the area with hatching in the opposite direction reveals limitations on the device when used with thin film modules due to the inadequate distance between the maximum MPP voltage and maximum DC voltage The area of maximum efficiency forms a plateau within a power range of 25 to 105 percent and up to an MPP voltage range of 424 V At higher voltages the buck converter is activated meaning conversion efficiency drops by 0 7 to 1 4 percentage points The vertical line at 60 percent of nomi nal power and the horizontal line at an MPP voltage of 350 V meet at the unit s maximum efficiency of 98 percent Therefore PHO TON Lab s measurements exceed the manu facturer s specification of a maximum effi ciency of 97 7 percent considerably At high MPP voltages maximum conversion effi ciency decreases by around 2 1 percentage points At low powers below 15 percent of nominal power efficiency decreases by 5 to 8 percentage points The power factor cos at
9. esults Measurements in our lab and examinations at AIT previously Arsenal Research did not detect the changes in MPP tracking behavior at very low powers We will examine and analyze these test results in greater detail 162 dition to technical data and general informa tion it contains descriptions of installation implementation and operating the inverter as well as instructions on troubleshooting and maintenance The users manual can also be down loaded from the manufacturers website in the following languages Czech Dutch English French German Italian Slovakian and Spanish The technical datasheet is also available in Greek and Portuguese Circuit design The IG TL 5 0 has a two stage topology is transformerless and has one MPP tracker for all of the strings First energy from the PV generator reaches a buck converter serving as a DC DC converter via an EMI filter The buck converter reduces the input voltage to a DC voltage of 440 V at most and feeds the voltage into an intermediate circuit which is connected to the output bridge In an MPP voltage range of 350 to 440 V the buck converter is by passed by a relay which de pending on the power results in a conver sion efficiency around 0 7 to 1 4 percentage points higher Via a subsequent output filter the output bridge feeds pulse width modu lated sinusoidal voltage into the grid All of the power semiconductors are located in a semiconductor module
10. fe operation the unit offers grid monitoring with all pole sensitive re sidual current protection and DC side in sulation monitoring according to the Ger man DIN VDE 0126 1 1 norm The grid is checked for correct impedance voltage fre quency and an appropriate DC share in the AC current while residual current monitor ing is carried out based on absolute values and changes in amplitude An insulation test on the solar generator which occurs prior to each connection to the grid checks the resistance between the generator s connec tions and the ground An unusual feature of the IG TL inverter is that it continually aligns and analyzes the current of attached strings The electrolytic capacitors in the power element have a temperature class of 105 C and are therefore well designed to handle ambient temperatures The device s status is shown with a display and three LEDs The inverter is equipped with one USB port a 12 V signal output as well as a Solar Net in put and output Software updates are easy to install a new version can simply be down loaded from Fronius website onto a USB stick and then transferred to the device via the USB port The Solar Net connections are used to integrate the unit into Fronius Dat com system for instance to communicate with additional inverters or irradiation and temperature sensors The 12 V signal out put normally open contact is available for connecting audible alarms visu
11. ncy drops when the buck converter is activated Course of overall efficiencies average overall efficiency and PHOTON efficien cy The PHOTON efficiency at medium irra diation and simulated decreasing DC power is 95 9 percent at high irradiation it reaches 96 2 percent When simulating an increase in DC power the PHOTON efficiency for medium irradiation is 0 2 percentage points lower at 95 7 percent Feed in at nominal power The inverter feeds in 100 percent of its nominal power over an input voltage range of 350 to 700 V at an ambient temperature of 25 C Displayed output power If the test can didate is fed with different powers between 5 and 110 percent of nominal power at a constant MPP voltage of 515 V so in the me dium range there are only slight deviations between the values displayed by the inverter and those taken by a power analyzer over the entire power range The difference fluctu ates between 0 7 and 1 4 percent There fore the display s accuracy is equivalent to that of a class B meter formerly known as precision class 1 In this context the users manual notes that the inverter s measuring device is not calibrated and that slight deviations up to a few percentage points can occur That kind of admission is one that PHOTON Lab would like to see other manufacturers make since a lot of devices are considerably less accurate than the IG TL 5 0 Operation at high temperatures The manufacturer specifie
12. our devices from the company s IG TL se ries finally hit the market The company at tributes the delay to the inverters being in a test phase However it seems more likely that Fronius like all inverter manufacturers at that point was suffering from supply is sues for important components The IG TL 5 0 which PHOTON Laboratory received in March after Fronius completed the usual test agreement was definitely one of the first of its kind to hit the lab s test bench While this device marks Fronius entry into the ranks of manufacturers offering transformerless devices the IG TL series is host to a number of other innovations as well The device is divided into two separate parts the front unit with the power elec tronics can be removed from the rear sec tion without dismantling the AC and DC connections hardly a conventional design Furthermore the datasheet promises excel lent performance which naturally piqued curiosity at PHOTON Lab about how well this newcomer would perform during tests Construction The IG TL series consists of the IG TL 5 0 with 4 600 W of AC nominal power the IG TL 3 0 with 3 000 W the IG TL 3 6 with 3 600 W and the IG TL 4 0 with 4 000 W All four models in the range are transformer less and are identical in terms of construc tion dimensions and weight The test candidate has a well arranged construction and appears simple to manu facture The first thing installers are likely
13. r circuit board which also contains the control unit is located on a higher level and is connected to the filter circuit board Soldered under neath the power circuit board is a transis tor module the heat losses from which are directed away via a small cooling element situated below the box The buck converter s and the sinusoidal filter s chokes are located above the power element circuit board cast in a cartridge inside the box There is a small DC powered fan for distributing heat inside the box on the same level as the cir cuit boards A DC circuit breaker is mounted at the bottom of the device on the unit that attaches to the wall There is also a plug in box for the communications circuit board The housing therefore consists of three pieces the wall bracket the central unit made of molded plastic and the cover made of aluminum sheeting The device has an IP 55 protection type and is therefore suitable for installation outdoors if protected from the elements Both the small internal fan and the cool ing element fan are easy to remove or ex change in the event of a malfunction The cooling element fan is subjected to sur rounding conditions and can therefore clog if operated in a dirty location In total six string cables and three grid cables are fed into the housing and directly attached to the terminal block All of the Photon International September 2010 cables are internally strain relieved To ensure sa
14. rable decrease 92 in efficiency 90 96 88 86 84 82 80 European weighted Euromax 97 4 78 Californian weighted NcecMax 97 2 76 74 72 10550 368 387 405 424 442 461 479 497 516 534 553 571 589 608 626 645 663 682 700 V mPp in V Pe Overall efficiency nsym in Overall efficiency ne s at different V pp voltages 98 96 The IG TL 5 0 appears to be more comfor table at low voltages However efficiency 94 develops as it should at all voltage levels 92 increasing steeply atthe start then remai 99 ning at a constant level shown here when si yi measured at decreasing powers 86 84 82 80 Vmr 350 0 V V 97 97 e Vip 700 0 V Vurppmay NgumMax 25 90 Average overall efficiency avgSumMax 96 54 MPPmin sumMax 78 76 Npmed 95 9 phigh 96 2 74 72 oe 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Nominal power Ppp Accuracy of inverter display ee 28 The Fronius inverter s display is highly ac Curate 30 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Nominal power Papp 160 Photon International September 2010 science amp technology inverters test Manufacturer s response The efficiency measurements match our own r
15. rature and irradiation values The time and date are also displayed The device also has a today mode in which the display informs users about oper 70 100 80 90 100 110 120 ating duration fed in energy the monetary value of the achieved yield whereby the tar iff level is entered by the operator choosing the applicable currency from over 20 differ ent countries available worldwide and an estimated value for CO savings as well as the maximum value for output power grid voltage and generator voltage In conjunc tion with the Sensor Box users can access MPPT adjustment efficiency increasing power If different power values are applied pro gressing from low to high powers the IG TL5 0 s MPP tracking precision decreases particularly at lower powers and voltages This causes the PHOTON efficiency to de crease slightly data on the maximum and minimum values for module and ambient temperatures as well as the maximum irradiation value Instruction manual The device also includes a very compre hensive and informative users manual It applies to all units in the IG TL range In ad science amp technology inverters test Weighted conversion efficiency tomeson ciency Neu cec in i NEuro manufacturer specified 97 3 The European efficiency is almost as high as the Californian efficiency over the entire MPP voltage range The use of a buck con 94 verter results in a conside
16. s a wide temperature range of 20 to 55 C Together with its IP 55 protection type that means the unit can be installed in either very cold or very warm locations for instance under a roof or out doors There are no temperature related power reductions to take into consideration when the ambient temperature increases Fronius inverter feeds 100 percent of its nominal power into the grid until around 55 3 C At that point the device reduces its power and efficiency falls but only by about 0 4 percentage points The selected operat ing point was 4 730 W of DC power and an MPP voltage of 515 V Overload behavior If the IG TL 5 0 is of fered an overload of 1 3 times its nominal input power so 6 149 W at an MPP voltage of 515 V and an ambient temperature of 27 C the unit limits its power to around 5 245 W which is 10 9 percent above the DC nom 164 inal power of 4 730 W Thus the device s overload range is quite large When power limitations take effect the unit pushes the operating point toward higher input volt ages The DC voltage adjusts itself to a value of around 568 V Own consumption and night consump tion The inverter s own consumption in its tested construction is up to 8 W on the AC side and 2 6 W on the DC side The manu facturer makes no specifications here At night the inverter consumes around 0 3 W of real power from the grid The manufac turer specifies 0 2 W Thermography Thermographic im
17. science amp technology inverters test Photon The Solar Power Magazine International A 96 2 at high irradiation 9 2010 www photon international com Photon The Solar Power Magazine International A 95 9 at medium irradiation 9 2010 www photon international com when measured with increasing DC powers see MPPT adjustment efficiency section the PHOTON efficiency was 95 7 percent but that also suffices for an A grade o Highlights The IG TL 5 0 is a transformerless inverter with a DC nominal power of 4 730 W The MPP range stretches from 350 to 700 V The unit s maximum conversion ef ficiency comes in at 98 percent the European efficiency is 97 4 percent while the Californian efficiency is 97 5 percent The PHOTON efficiency is 95 9 per cent at medium irradiation with de creasing DC power but 95 7 percent with increasing DC power it hits 96 2 percent at high irradiation The unit s IP 55 protection type and low dependence on operational and ambient temperatures allow for in stallation in a variety of locations 156 A successful debut Fronius submitted a device from its first transformerless inverter series to PHOTON Laboratory for testing and the IG TL 5 0 made a very good impression ronius International GmbH based in Wels Austria presented its first transfor merless inverter at the European Intersolar trade fair in June 2009 Then after 6 months f
18. to notice is the unusual concept for attach ing the unit to the wall and hooking the unit up electrically the wall bracket has an integrated connection area with terminal blocks The connectors that attach to the blocks are located on the bottom of the pow er element s box Therefore when installing the unit first the wall bracket is installed and then the connectors are attached to the clamps integrated in the bracket The actual inverter is located in a box that is inserted onto the wall bracket via four tracks and then latched into the terminal blocks Fi nally the two separate pieces are secured together using six screws The goal of this construction is to facilitate service and maintenance For most repairs the device s core can be removed from the bracket and replaced with a substitute for instance a device with a new circuit board The box with the device s central unit has its own cover Once removed the inside of the inverter is on display At the bottom a filter circuit board holds the power connec tions the DC and AC side EMI filters as Photon International September 2010 photon pictures com 3 Nid A The rear section of the IG TL 5 0 which is attached to the wall contains the connectors and a slot for the communications circuit board The box with the actual inverter is then inserted into this section Thermographic images showed no problematic temperatures well as six string fuses The powe
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