A three-level IGBT module active power test system

Abstract

The invention discloses a three-level IGBT module active power test system, comprising a front-end bidirectional DC power supply module, an inverter power supply module, a controller module and an isolation transformer, wherein the inverter power supply module comprises an IGBT test fixture and an intermediate DC capacitor group; the IGBT test fixture is used to place the three-level IGBT module to be tested; the intermediate DC capacitor group is connected and arranged on the DC side of the three-level IGBT module to be tested, and forms the DC side of the inverter power supply module, and the AC side of the three-level IGBT module to be tested forms the inverter side of the inverter power supply module; the front-end bidirectional DC power supply module is electrically connected to the DC side of the inverter power supply module; the AC side of the inverter power supply module is connected to the AC power grid through the isolation transformer; the controller module is signal-connected to the inverter power supply module, and is used to send a driving pulse signal to the three-level IGBT module to be tested, so as to control the operation of the three-level IGBT module active power test system, and monitor the operation state and temperature state of the three-level IGBT module wafer to be tested.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a three-level IGBT module active power test system. Background Art

[0002] The semiconductor IGBT manufacturing process can be divided into front-end and back-end processes, of which the front-end (FrontEnd) is mainly the manufacturing and testing of wafers, and the back-end (BackEnd) is mainly the packaging and testing of modules. With the rapid development of front-end process miniaturization and integration technology, the importance of back-end processes has become increasingly prominent. As a core breakthrough point that can increase the creation of new added value for semiconductors, its technological development is attracting much attention.

[0003] With the explosive growth of the photovoltaic industry in recent years, the demand for IGBT modules has surged, and the production technology level of chips has also been improved simultaneously. The existing technology has reached the same level as imported devices in front-end chip technology, but the stability of back-end module design and manufacturing quality needs to be further improved. In addition to static and dynamic tests at the device level, system-level active testing experiments need to be added. Therefore, it is necessary to design an IGBT power module for large-scale industrial and commercial / ground grid-connected and energy storage inverters, and develop an active testing system. This system can simulate the application conditions of IGBT modules in photovoltaic power station scenarios, and perform module-level active tests such as wafer thermal testing, long-term full-load operation, and life testing. Summary of the invention

[0004] In order to overcome the above disadvantages, the object of the present invention is to provide a three-level IGBT module active power test system to solve the problems raised in the above background technology.

[0005] In order to achieve the above objectives, the technical solution adopted by the present invention is a three-level IGBT module active power test system, including a front-end bidirectional DC power supply module, an inverter power supply module, a controller module and an isolation transformer, wherein:

[0006] The inverter power module includes an IGBT test fixture and an intermediate DC capacitor group. The IGBT test fixture is used to place the three-level IGBT module to be tested. The intermediate DC capacitor group is connected to the DC side of the three-level IGBT module to be tested and forms the DC side of the inverter power module, and the AC side of the three-level IGBT module to be tested forms the inverter side of the inverter power module.

[0007] The front-end bidirectional DC power supply module is electrically connected to the DC side of the inverter power supply module to provide a DC bus voltage with a wide voltage range. The AC side of the inverter power supply module is connected to the AC power grid through the isolation transformer to convert AC power of different voltage levels into 380V / 50Hz industrial frequency AC power through the isolation transformer and feed it back to the input end of the front-end bidirectional DC power supply module to form an internal circulation.

[0008] The controller module is signal-connected to the inverter power module, and is used to send a driving pulse signal to the three-level IGBT module to be tested, so as to control the operation of the three-level IGBT module active power test system and monitor the operating state and temperature state of the three-level IGBT module wafer to be tested.

[0009] Furthermore, the inverter power supply module further includes an LCL filter circuit, which is connected to the AC side of the three-level IGBT module and is used to be connected to the isolation transformer through the LCL filter circuit.

[0010] Furthermore, the intermediate DC capacitor group includes an electrolytic capacitor, a gold film capacitor and an air inductor. The electrolytic capacitor and the gold film capacitor are sequentially connected in parallel to the DC side of the three-level IGBT module to be tested, and the air inductor is connected in series between the electrolytic capacitor and the gold film capacitor.

[0011] Furthermore, the controller module includes a DSP control unit, a CPLD control unit and an ARM processor. The DSP control unit is connected to the three-level IGBT module for PWM modulation to output sinusoidal AC current. The CPLD control unit is used for inverter wave timing processing and protection logic wave blocking. The ARM processor is used for external communication.

[0012] Furthermore, the front-end bidirectional DC power supply module includes 16 single power supplies, which are connected in two series and eight in parallel. The single power supply has a rated power of 30kW and a maximum voltage of 1000V, which is used to meet the wide range of front-end DC source voltage requirements.

[0013] Furthermore, the three-level IGBT module active power test system also includes a three-way inductor matching module. The three-way inductor matching module is arranged between the inverter side of the inverter power module and the LCL filter circuit, and includes three branches, each branch is provided with an AC inductor and a contactor, which is used to make the three-way inductor matching module match three voltage levels of 380 / 690 / 800V respectively, and switch the selection through the contactor.

[0014] Furthermore, the three-level IGBT module active power test system also includes a heat dissipation module, which includes an air outlet hood, an isolation transformer heat dissipation fan and an inductor heat dissipation fan. The air outlet hood is arranged above the front-end bidirectional DC power supply module, and the isolation transformer heat dissipation fan is arranged below the isolation transformer.

[0015] Furthermore, the heat dissipation module also includes a water cooling unit, which is arranged below the IGBT test tooling and is used to control the temperature of the three-level IGBT module to be tested so as to achieve performance testing of the three-level IGBT module wafer to be tested at different temperatures. The inductor cooling fan and the water cooling unit are both arranged close to the three-way inductor matching module.

[0016] Furthermore, the three-level IGBT module is one of an NPC-1 type three-level IGBT module, an NPC-2 type three-level IGBT module or an ANPC type three-level IGBT module.

[0017] Furthermore, the three-level IGBT module active power test system adopts a grid-connected inverter control strategy, and the grid-connected inverter control strategy includes a phase-locked loop control strategy and a grid-connected inverter control strategy.

[0018] Compared with the prior art, the three-level IGBT module active power test system provided by the present application has the following beneficial effects: the active current of the IGBT module is controlled by the control module grid-connected control software, so that the wafer can simulate the operation of the device in the real application environment in the laboratory. Through a safe and low-cost testing method, the rationality of the IGBT module wafer design scheme and the performance of each tube before leaving the factory are verified, and the test results are comprehensive and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A circuit diagram of an embodiment of a three-level IGBT module active power test system of the present invention;

[0020] Figure 2 This is a system overall block diagram of an embodiment of a three-level IGBT module active power test system of the present invention;

[0021] Figure 3 It is a circuit diagram of an inverter power supply module of an embodiment of a three-level IGBT module active power test system of the present invention;

[0022] Figure 4 A controller module circuit diagram of an embodiment of a three-level IGBT module active power test system of the present invention;

[0023] Figure 5 A schematic diagram of an intermediate DC capacitor group of an embodiment of a three-level IGBT module active power test system of the present invention;

[0024] Figure 6 The inductor current waveform diagram of an embodiment of a three-level IGBT module active power test system of the present invention is shown in FIG. 1 , wherein the waveform diagram is within a switching cycle;

[0025] Figure 7 This is a front structural layout diagram of an embodiment of a three-level IGBT module active power test system of the present invention;

[0026] Figure 8 This is a back structural layout diagram of an embodiment of a three-level IGBT module active power test system of the present invention;

[0027] Fig. 9 Infrared thermal images of six wafers of three-level IGBT modules to be tested measured by a high-speed thermal imager. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0029] refer to Figure 1 and Figure 2 , Figure 1 A circuit diagram of a three-level IGBT module active power test system provided by an embodiment of the present invention is shown; Figure 2 The overall system block diagram of a three-level IGBT module active power test system provided by an embodiment of the present invention is shown; Figure 3 The invention shows a circuit diagram of an inverter power supply module of a three-level IGBT module active power test system provided by an embodiment of the present invention; Figure 4 A circuit diagram of a controller module of a three-level IGBT module active power test system provided by an embodiment of the present invention is shown; Figure 5 A schematic diagram of an intermediate DC capacitor group of a three-level IGBT module active power test system provided by an embodiment of the present invention is shown; Figure 6 An inductor current waveform diagram of an active power test system for a three-level IGBT module provided by an embodiment of the present invention is shown, wherein the waveform diagram is within a switching cycle.

[0030] like Figure 1 and Figure 2 As shown, the technical solution adopted by the present invention is a three-level IGBT module active power test system, including a front-end bidirectional DC power supply module, an inverter power supply module, a controller module and an isolation transformer, wherein:

[0031] The inverter power module includes an IGBT test fixture and an intermediate DC capacitor group. The IGBT test fixture is used to place the three-level IGBT module to be tested. The intermediate DC capacitor group is connected to the DC side of the three-level IGBT module to be tested and forms the DC side of the inverter power module. The AC side of the three-level IGBT module to be tested forms the inverter side of the inverter power module.

[0032] The front-end bidirectional DC power module is electrically connected to the DC side of the inverter power module to provide a DC bus voltage with a wide voltage range. The AC side of the inverter power module is connected to the AC grid through an isolation transformer to convert AC power of different voltage levels into 380V / 50Hz industrial frequency AC power through the isolation transformer and feed it back to the input end of the front-end bidirectional DC power module to form an internal circulation.

[0033] The controller module is connected to the inverter power module signal, and is used to send a driving pulse signal to the three-level IGBT module to be tested, so as to control the operation of the three-level IGBT module active power test system and monitor the operating status and temperature status of the three-level IGBT module wafer to be tested.

[0034] The system input line sampling molded case circuit breaker combined with AC contactor, the input circuit breaker selection is 250A / 3P, and the AC contactor contactor sampling is 800A / 3P. The DC power supply is provided by 8 2000V / 60kW power supplies in parallel to provide a stable DC 400~2000V, and then the DC is inverted into AC through the inverter circuit. The isolation transformer primary transformer selects different voltage level taps through the contactor to achieve 380 / 690 / 800V three grid options, and the secondary side outputs AC380V back to the input end of the DC power supply.

[0035] The inverter power supply module also includes an LCL filter circuit, which is connected to the AC side of the three-level IGBT module and is used to be connected to the AC power grid through the LCL filter circuit.

[0036] The module controller is responsible for monitoring the operating status and temperature status of the IGBT, as well as the status of the DC power supply circuit. The module controller includes a DSP control unit, a CPLD control unit, and an ARM processor. The DSP control unit is connected to the three-level IGBT module for PWM modulation to output sinusoidal AC current. The CPLD control unit is used for inverter wave timing processing and protection logic blocking. The ARM processor is used for external communication.

[0037] Power semiconductor IGBT module active test system Figure 2 As shown in the figure, it is mainly composed of three-level circuits: DC power supply + three-level inverter + isolation transformer. It is designed according to the photovoltaic inverter circulating current load test method and can simulate the real load condition of IGBT in the inverter.

[0038] At the front end, the DC source provides a stable DC bus voltage of 400~2000Vdc, and the back end is composed of the IGBT module under test as the core, plus the driver board, sampling board, capacitor board, LCL filter board, main control board, etc. to form a complete grid-connected inverter system. The IGBT analog inverter uses PWM modulation to invert the output sinusoidal AC current and realizes loading by controlling the current size of the grid. Finally, the sinusoidal AC output by the IGBT converts the AC of different voltage levels into 380V / 50Hz industrial frequency AC through the isolation transformer and feeds it back to the input end of the DC device to form an internal loop. The front-end DC source is composed of two series and eight parallel connections. The single-machine power supply adopts the HD100G power supply series products, with a rated power of 30kW, a maximum voltage of 1000V, and a total rated power of 480kW.

[0039] Corresponding drive circuits are built for different types of IGBTs to form independent tooling. By replacing the tooling, different modules can be tested, which can support the three-level modules commonly used by NPC-1, NPC-2, and ANPC. The AC side isolation transformer is set with three voltage taps of AC380V / 690V / 800V. The grid specification is selected through the contactor, and the maximum grid-connected power is 450kW.

[0040] The design idea of ​​the inverter system string photovoltaic inverter is to add the IGBT module to the driver board, sampling board, capacitor board, and LCL filter board to form a complete grid-connected inverter system. For NPC-1, NPC-2, and ANPC, the commonly used three-level modules can be packaged into independent modules together with the driver board to form tooling to realize the replacement of different modules, and other single boards can be reused. The main circuit diagram is as follows Figure 3 As shown, the main circuit is mainly composed of three parts: DC bus capacitor, inverter drive, and output LCL filter unit.

[0041] like Figure 4As shown, the module controller is responsible for monitoring the operating status and temperature status of the IGBT, and is also responsible for monitoring the status of the DC power supply circuit. The module controller includes a DSP control unit, a CPLD control unit and an ARM processor. The DSP control unit is connected to the three-level IGBT module for PWM modulation to output sinusoidal AC current. The CPLD control unit is used for inverter wave timing processing and protection logic blocking. The ARM processor is used for external communication. The inverter control circuit main control board adopts the DSP+CPLD+ARM mode. The DSP adopts a TMS320F28374S from TI to control the inverter circuit, the CPLD adopts the EF2L45LG148 from Anlu Company to process the inverter wave timing and protect the logic blocking, and the ARM adopts the ST series M32H745 from ST series to communicate with the outside.

[0042] Since the three-phase power grid is an unbalanced system, the grid voltage includes positive sequence, negative sequence, and zero sequence components. The phase-locked loop control strategy is adopted. Under the condition of voltage imbalance, the second harmonic component caused by the negative sequence voltage component is eliminated through the decoupling network, thereby suppressing the influence of the three-phase voltage imbalance on the accuracy of the phase-locked loop. DSRF-SPLL can accurately detect the amplitude, phase, and frequency of the positive and negative sequence components.

[0043] This scheme is based on the grid voltage vector control algorithm (VOC) algorithm for control. The control system consists of a DC voltage outer loop and an active and reactive current inner loop. The PQ module outputs the id current command control system to output active power, and controls the iq current command to control the system output reactive power. When iq*= 0, the system is unity power factor control. When iq*< 0, the system outputs inductive reactive power. When iq*> 0, the system outputs capacitive reactive power.

[0044] The current inner loop is implemented in the dq coordinate system, and the PI regulator is used to achieve zero-static error control of the current id and iq. The control system adds feedforward control to compensate for the impact of voltage fluctuations on the control system. The current inner loop command and the feedforward command output command are transformed into a three-phase modulation signal through Park-1 transformation, and the three-phase switching signals Sa, Sb, and Sc are obtained through SVPWM modulation to achieve grid-connected inverter control.

[0045] like Figure 5As shown, the DC bus voltage requires an intermediate capacitor to stabilize the voltage. The intermediate bus capacitor has two functions: smoothing DC voltage fluctuations and absorbing high-frequency ripple currents. A combination of gold film capacitors and electrolytic capacitors can be used. The gold film capacitor is close to the IGBT side. Its main function is to absorb high-frequency harmonic currents. On the one hand, the number is related to the inverter inductor ripple current. The number is determined comprehensively in combination with the simulation results. The electrolytic capacitor mainly provides steady-state energy. When the grid-connected power is set to change suddenly from no-load 0 to 100% full-load, the intermediate support capacitor needs to provide transient energy within the response time of 10ms. In order to allow high-frequency ripple currents to be provided by gold film capacitors as much as possible, a 5uH hollow inductor is reserved between the electrolytic capacitor and the gold film capacitor.

[0046] The design of LCL filter circuit needs to be based on the specifications of the inverter. Different inverters need to design different filter parameters. Here we take the current 320kW string photovoltaic inverter parameters as an example:

[0047] The grid rated voltage is 800V, the maximum output current is 254A, the switching frequency is 16kHz, the DC bus rated voltage is 1300V, and the switching current ripple amplitude is the largest at the grid voltage peak. The inductor current waveform in one switching cycle is as follows: Figure 6 As shown, taking phase A as an example, the KVL equation of the entire circuit can be written as:

[0048] (3-1)

[0049] At (t0~T1), substituting Sa=0 into formula (3-1) yields:

[0050] (3-2)

[0051] When (T1 company ~ tpwm), substituting Sa = 1 into formula (3-1) yields:

[0052] (3-3)

[0053] From formula (3-2) and formula (3-3), we can get:

[0054] (3-4)

[0055] Formula (3-4) is a quadratic function with a maximum value of 12 / Udc. The inverter inductor current ripple is 0.35. Calculate the filter inductance:.

[0056] (3-5)

[0057] Due to the nonlinearity of the inverter inductor, the output current changes sinusoidally, the inductance is large when the current is small, and the minimum value of the inverter inductor is 54uH. In this embodiment, the inverter inductor parameters use the Sunshine inductor parameter scheme, the initial inductance of the independent inductor design is 110uH, and the inductance at the rated load peak current is 58uH. This product has been verified in Sunshine power supply products. The grid-side inductance Lg is 1 / 6~1 / 3 of the inverter inductance Linv, and Lg is 12uH.

[0058] For the calculation of filter capacitor, the reactive power on the capacitor is less than 2% of the maximum power of the whole machine, and the capacitor capacity can be estimated:

[0059] (3-6)

[0060] The capacitor capacity is 40uF, using Farad C6A series C6AU1106KM1A382 with a rated voltage of 600Vac, a single capacitor of 10uF, and 4 10uF capacitors per phase connected in parallel in a Y shape. The capacitor size is W*H*T=657*70*35mm, and a copper strip is laid on the bottom of the PCB board to pad the bottom of the capacitor for ventilation to enhance heat dissipation.

[0061] LCL filter resonant frequency:

[0062] (3-7)

[0063] The resonant frequency meets 10fn ≤fr ≤0.5fsw, and the resonant frequency is close to 0.5fsw. When other conditions remain unchanged, the grid-side inductance increases, and the resonant frequency will decrease. The cable from the on-site inverter to the box transformer will increase the grid-side inductance Lg, and the resonant frequency will be lower than that of formula 3-7.

[0064] refer to Figure 7 and Figure 8 , Figure 7 A front structural layout diagram of a three-level IGBT module active power test system provided by an embodiment of the present invention is shown; Figure 8 The diagram shows the back structure layout of a three-level IGBT module active power test system provided by an embodiment of the present invention.

[0065] In some embodiments, reference Figure 7 and Figure 8 The three-level IGBT module active power test system also includes a heat dissipation module, which includes an air outlet hood, an isolation transformer cooling fan, and an inductor cooling fan. The air outlet hood is located above the front-end bidirectional DC power module, the isolation transformer cooling fan is located below the isolation transformer, and the inductor cooling fan and the water cooling unit are both located close to the three-way inductor matching module.

[0066] The three-level IGBT module active power test system also includes a three-way inductor matching module. The three-way inductor matching module is arranged between the inverter side of the inverter power module and the LCL filter circuit, and includes three branches, each of which is provided with an AC inductor and a contactor, which is used to make the three-way inductor matching module match the three voltage levels of 380 / 690 / 800V respectively, and switch the selection through the contactor.

[0067] The heat dissipation module also includes a water cooling unit, which is arranged below the IGBT test fixture and is used to control the temperature of the three-level IGBT module to be tested, so as to achieve performance testing of the three-level IGBT module wafer to be tested at different temperatures.

[0068] The IGBT driver board and heat dissipation substrate are integrated on the test fixture, and the fixture can be replaced manually. Three AC inductors are integrated under the operating table to match three voltage levels of 380 / 690 / 800V, which are switched and selected through contactors. The square wave output by the IGBT is filtered into a sine wave through the LCL filter, and the energy is then transmitted back to the input end by the isolation transformer. The whole machine control circuit is realized by the communication connection between the industrial computer and the DC source and the inverter control module.

[0069] The three-level IGBT module active power test system provided in the present application, for the wafer temperature rise test, in this device, by setting the operating state of the inverter and the temperature of the radiator copper substrate, the actual temperature of the wafer is measured by a high-speed thermal imager to evaluate the steady-state thermal characteristics of the wafer and the parallel current sharing characteristics of the wafer. For the high and low temperature cycle load test, the machine is normally connected to the grid and runs at full load. By setting the temperature cycle of the water-cooled radiator copper substrate, the environmental adaptability of the IGBT and the reliability of the whole machine operation are verified. For the high temperature limit test, the machine is normally connected to the grid and runs at full load, and the operating characteristics of the wafer under the temperature extreme temperature of the radiator copper substrate are set. In addition, other related tests can be performed by changing the corresponding power parameters or voltage parameters, such as input power mutation test, voltage or frequency adaptability test, PWM modulation strategy test, etc.

[0070] refer to Fig. 9 , Fig. 9 Infrared thermal images of six wafers of three-level IGBT modules to be tested measured by a high-speed thermal imager.

[0071] In some embodiments, the infrared thermal imaging instrument used can monitor the temperature distribution of the IGBT module during operation in real time. When performing a wafer temperature rise test, the IGBT module is first installed on a radiator, and the relevant parameters of the power cycle experiment are set. Specifically, the experimental conditions in this embodiment are: simulating on-site photovoltaic application scenarios, the DC power supply controls the DC side voltage DC850V, the AC side voltage AC380V, the grid-connected feedback power 110kW test, and the grid-connected power factor PF=1. Then a power cycle experiment is performed to cause the IGBT module to generate power loss during repeated on and off processes, resulting in an increase in the module temperature. An infrared thermal imager is used to detect the temperature field of the IGBT module in the power cycle experiment to obtain the actual operating temperature data of the wafer, such as Fig. 9 As shown, from the infrared thermal image of the thermal imager, it can be observed that in the three-level IGBT module to be tested, the temperatures of the six wafers are 133.1°C, 144.1°C, 148.2°C, 125.5°C, 133.1°C and 136.3°C respectively, the highest temperature in the wafer is 148.2°C, the lowest temperature is 125.5°C, and the temperature difference is 22.7°C. By analyzing the temperature rise of the wafer through the temperature data obtained by infrared thermal imaging, the thermal characteristics of the wafer under different working conditions, such as thermal gradient, hottest point and other information, can be observed to verify and evaluate the steady-state thermal characteristics of the wafer, so as to perform wafer temperature rise test.

[0072] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A three-level IGBT module active power test system, characterized in that: It includes a front-end bidirectional DC power supply module, an inverter power supply module, a controller module and an isolation transformer, among which: The inverter power module includes an IGBT test fixture and an intermediate DC capacitor group; the IGBT test fixture is used to place the three-level IGBT module to be tested; the intermediate DC capacitor group is connected to the DC side of the three-level IGBT module to be tested and forms the DC side of the inverter power module, and the AC side of the three-level IGBT module to be tested forms the inverter side of the inverter power module; The front-end bidirectional DC power supply module is electrically connected to the DC side of the inverter power supply module to provide a DC bus voltage with a wide voltage range; the AC side of the inverter power supply module is connected to the AC power grid through the isolation transformer to convert AC power of different voltage levels into 380V / 50Hz industrial frequency AC power through the isolation transformer and feed it back to the input end of the front-end bidirectional DC power supply module to form an internal circulation; The controller module is signal-connected to the inverter power module, and is used to send a driving pulse signal to the three-level IGBT module to be tested, so as to control the operation of the three-level IGBT module active power test system, and monitor the operating state and temperature state of the three-level IGBT module wafer to be tested; The inverter power supply module further includes an LCL filter circuit, which is connected to the AC side of the three-level IGBT module and is used to be connected to the isolation transformer through the LCL filter circuit; The intermediate DC capacitor group includes an electrolytic capacitor, a gold film capacitor and an air inductor; the electrolytic capacitor and the gold film capacitor are sequentially connected in parallel to the DC side of the three-level IGBT module to be tested, and the air inductor is connected in series between the electrolytic capacitor and the gold film capacitor.

2. The three-level IGBT module active power test system according to claim 1, characterized in that: The controller module includes a DSP control unit, a CPLD control unit and an ARM processor; the DSP control unit is communicatively connected to the three-level IGBT module for PWM modulation to output sinusoidal AC current; the CPLD control unit is used for inverter wave timing processing and protection logic wave blocking; the ARM processor is used for external communication.

3. The three-level IGBT module active power test system according to claim 1, characterized in that: The front-end bidirectional DC power supply module includes 16 single-machine power supplies, and is composed of two series and eight parallel connections; the single-machine power supply has a rated power of 30kW and a maximum voltage of 1000V, which is used to meet the wide range requirements of the front-end DC source voltage.

4. The three-level IGBT module active power test system according to claim 1, characterized in that: It also includes a three-way inductor matching module; the three-way inductor matching module is arranged between the inverter side of the inverter power module and the isolation transformer, and includes three branches, each branch is provided with an AC inductor and a contactor, which is used to make the three-way inductor matching module match the three voltage levels of 380 / 690 / 800V respectively, and switch the selection through the contactor.

5. The three-level IGBT module active power test system according to claim 4, characterized in that: It also includes a heat dissipation module, which includes an air outlet hood, an isolation transformer heat dissipation fan and an inductor heat dissipation fan; the air outlet hood is arranged above the front-end bidirectional DC power supply module, and the isolation transformer heat dissipation fan is arranged below the isolation transformer.

6. The three-level IGBT module active power test system according to claim 5, characterized in that: The heat dissipation module also includes a water cooling unit, which is arranged below the IGBT test fixture and is used to control the temperature of the three-level IGBT module to be tested so as to achieve performance testing of the three-level IGBT module wafer to be tested at different temperatures; the inductor heat dissipation fan and the water cooling unit are both arranged close to the three-way inductor matching module.

7. The three-level IGBT module active power test system according to claim 1, characterized in that: The three-level IGBT module is one of an NPC-1 type three-level IGBT module, an NPC-2 type three-level IGBT module or an ANPC type three-level IGBT module.

8. The three-level IGBT module active power test system according to claim 1, characterized in that: A grid-connected inverter control strategy is adopted, and the grid-connected inverter control strategy includes a phase-locked loop control strategy and a grid-connected inverter control strategy.

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