Multi-device power cycle test equipment and test method

Abstract

The invention relates to the technical field of multi-device power cycle testing, in particular to multi-device power cycle testing equipment which comprises a main machine body, a heating system is arranged on the main machine body, and the heating system is used for electrifying and heating an IGBT module and an MOSFET module. The heating system comprises a plurality of branch test jigs and an auxiliary test jig, the branch test jigs are connected in parallel through cables, and the branch test jigs and the auxiliary test jig are also connected in parallel through cables. When one branch is tested, other branches are closed, after one branch is tested, the other branch is opened, and devices in the heated branch are cooled by utilizing test time intervals, so that on one hand, constant output of current of the direct current source can be ensured, on the other hand, the number of the tested devices is greatly increased, and the test efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-device power cycle testing, and specifically provides a multi-device power cycle testing apparatus and a testing method. Background Art

[0002] High-voltage high-power devices such as insulated gate bipolar transistors (IGBTs) or silicon carbide metal-oxide-semiconductor field effect transistors (SiC MOSFETs) are widely used in power conversion systems such as offshore wind power, photovoltaic power generation, and electric vehicles. The definition of the long-term operation reliability of power semiconductor devices in the standards of the International Electrotechnical Commission is the ability of the device to complete the specified functions within the specified time. The main experiments for evaluating the long-term operation reliability of power semiconductor devices include: high-temperature gate bias, high-temperature reverse bias, power cycle, and temperature cycle, etc. Among them, the power cycle test is the most important experiment for evaluating the long-term operation reliability of power semiconductor devices. By applying a corresponding heating current to the device under test to increase the device junction temperature to the specified junction temperature, and then cutting off the heating current to cool it down, and repeating the heating and cooling processes to age the device, which is also called active temperature cycling. The power cycle test is the most effective means to establish a life model of power semiconductor devices, evaluate the life, and assess the long-term operation reliability through equivalent accelerated aging, and it is also an indispensable test for improving the packaging reliability of devices during the device R & D process. For high-voltage high-power IGBT devices, their capacity and reliability have been greatly improved, so very high requirements are put forward for the power cycle test equipment for evaluating their long-term operation reliability in terms of test capacity, measurement accuracy, test efficiency, and long-term operation reliability of the equipment.

[0003] During the test process of the existing test equipment, the DC current source enters the idle state after heating in a single branch, resulting in discontinuous power output. It often fails to effectively utilize the cooling time of each branch under test, resulting in unstable output of the DC current source current and not fully utilizing the time window during the cooling stage of the device under test. In this mode, the current source needs to be frequently started and stopped to match the heating cycles of different branches, resulting in loss of power output efficiency, limiting the number of devices under test, and reducing the test efficiency. Summary of the Invention

[0004] I. Technical Problems to be Solved

[0005] In view of the above-mentioned defects existing in the prior art, the present invention particularly provides a multi-device power cycle testing apparatus and a testing method, which solve the problem of effectively and efficiently testing the above-mentioned devices by providing multiple test branches, and each test branch can test multiple modules simultaneously.

[0006] II. Technical Solutions

[0007] To solve the above technical problems, the present invention provides a multi-device power cycle test device. By passing current into the IGBT module and the MOSFET module to heat the IGBT module and the MOSFET module, the aging degree of the IGBT module and the MOSFET module is tested. It includes a main body, on which a heating system is provided. The heating system is used to energize and heat the IGBT module and the MOSFET module. The heating system includes a plurality of branch test fixtures and an auxiliary test fixture. Each branch test fixture is connected in parallel through a cable, and the branch test fixture and the auxiliary test fixture are also connected in parallel through a cable. An IGBT module and a plurality of MOSFET modules are placed in the branch test fixture. The IGBT module and the MOSFET module are connected in series through a circuit. An IGBT module is placed in the auxiliary test fixture. Conductive contacts capable of conducting electricity with the IGBT module and the MOSFET module are respectively provided in the branch test fixture and the auxiliary test fixture. A water cooling system for dissipating heat from the IGBT module and the MOSFET module is also provided on the main body.

[0008] Preferably, the heating system further includes a plurality of branch switches provided on the main body and corresponding to the branch test fixtures respectively, for controlling the current flowing into the IGBT module and the MOSFET module. When the IGBT module and the MOSFET module in one of the branch test fixtures are energized and heated, no current flows into the other branch test fixtures.

[0009] Preferably, the heating system further includes a hub provided on one side away from the branch switch. Each branch test fixture and the auxiliary test fixture are connected to the hub through a cable. A main switch is also provided on the main body near the hub. The hub is connected to the main switch through a cable. The main switch and one of the branch switches are electrically connected to the heating current source through a cable.

[0010] Preferably, measuring terminals are also provided on the branch test fixture and the auxiliary test fixture. The measuring terminals are electrically connected to the IGBT module and the MOSFET module. A control panel is also provided on the main body.

[0011] Preferably, a measuring protection circuit is also provided inside the control panel. An NI data acquisition card for collecting data of the IGBT module and the MOSFET module is also provided inside the control panel. A drive circuit for driving the heating system and the water cooling system to operate is also provided inside the control panel.

[0012] Preferably, the water cooling system includes a lifting component and a cold water circulation component. The lifting component includes a plurality of cooling plates corresponding to the branch test fixture and the auxiliary test fixture respectively and capable of moving up and down. A plurality of heat conducting plates for contacting and conducting heat with the IGBT module and the MOSFET module are further arranged at the bottom of the cooling plate. The lifting component further includes a lifting structure capable of moving the cooling plate up and down.

[0013] Preferably, the lifting structure includes a support frame fixed to the top of the main body, and a telescopic driving member is vertically fixed to the top of the support frame. The output end of the telescopic driving member is connected to the cooling plate.

[0014] Preferably, the cold water circulation component includes a water tank fixed to the outside of the main body. A circulation pump is further fixed inside the water tank. The water outlet end of the circulation pump is connected to a first pipeline, and the first pipeline is connected to the cooling plate. A cavity for water flow is provided inside the cooling plate. The cold water circulation component further includes a second pipeline connected to the cooling plate. The water cooling system further includes a radiator fixed to the water tank. The radiator is formed by connecting a plurality of heat conducting fins and heat dissipation tubes. The heat dissipation tubes are arranged in an "S" shape in the heat conducting fins. One end of the second pipeline is connected to the heat dissipation tube, and the other end of the heat dissipation tube is connected to the water tank through a pipeline.

[0015] Preferably, the cold water circulation component further includes a cooling fan arranged on the radiator for dissipating heat from the radiator.

[0016] 10. A multi-device power cycle test method, including a multi-device power cycle test device in the above solution, having the following steps:

[0017] S1: Place the IGBT module and the MOSFET module to be tested into the branch test fixture and the auxiliary test fixture, and move the cooling plate downward through the telescopic driving member. The cooling plate presses the heat conducting plate on the IGBT module and the MOSFET module, so that the IGBT module and the MOSFET module are in contact with the conductive contacts.

[0018] S: After the preparation work is completed, turn on the 15kW / 750A load power supply and the 100 - 500mA measurement current source. The drive circuit outputs a continuously adjustable drive voltage of -10V to +20V according to the test requirements. The control program inside the control panel flexibly adjusts the test mode according to the test requirements. The heating current source maintains a constant current output. When one of the branches is conducting, the other branches are not conducting. The MOSFET module under test is continuously heated. The conduction logic of the IGBT module in the auxiliary test fixture needs to be judged according to whether the output current of the heating current source is greater than the current specification of the MOSFET module under test. If the load current is equal to the current specification of the MOSFET module under test, the drive circuit turns off the current of the IGBT module in the auxiliary test fixture. If the load current is greater than the current specification of the MOSFET module under test, the drive circuit adjusts to turn on the IGBT module in the auxiliary test fixture for shunting, so that the current value flowing through the MOSFET module under test just meets its current specification. After the conduction time ends, turn off the IGBT module in the auxiliary test fixture, and then turn on another branch for testing. Water-cool the devices on the branch that has been heated, and collect information such as the saturation voltage drop and transient thermal impedance at low current.

[0019] S3: The power cycle test device integrates online real-time monitoring functions such as transient thermal impedance curve, thermal resistance, junction temperature, and forward voltage drop. In order to accurately obtain the temperature change of the module during the cooling process, the transient thermal impedance curve of the module is obtained through the temperature relationship curve. When the electrical parameters of the device under test exceed the aging index, the control drive chip outputs a turn-off signal and outputs a turn-off acquisition signal.

[0020] III. Beneficial Effects

[0021] Compared with the prior art, the present invention is provided with multiple parallel test branches, each branch is independently configured, and the on and off states can be controlled separately to meet the test requirements of different devices under test. Specifically, when a device under test on a certain branch is selected for testing, the system provides a stable DC current to the branch to heat the device under test on it to a preset temperature. At the same time, other non-test branches remain in the off state to avoid unnecessary energy consumption and potential interference. The key advantage of this design is that it allows the system to take turns testing multiple devices under test at the same time without waiting for a single device test to complete before proceeding to the next. This parallel processing method greatly improves the test efficiency, especially in large-scale device test scenarios, where its advantages are particularly obvious.

[0022] When the system detects that the device under test on a certain branch has been heated up, the circulation pump is started. As the power source of the water cooling system, the circulation pump is responsible for driving the cold water in the water tank into the cooling plate. The cooling plate is closely attached to the heat-generating components of the IGBT module and the MOSFET module through the built-in heat conduction plate. The heat conduction plate is made of a high thermal conductivity material, which can effectively absorb the heat generated by the device under test and transfer it to the water flow passing through the cooling plate. The water flow carrying heat passes through the heat dissipation tubes in the radiator. The heat dissipation tubes and the heat dissipation fins increase the heat dissipation area. A heat dissipation fan is also equipped on the top of the radiator. When the heat dissipation fan starts, it generates an air flow, accelerating the air flow around the radiator, thereby taking away the heat released by the heat dissipation tubes and the heat dissipation fins and achieving efficient heat dissipation.

[0023] The constant output of the DC current source is realized, and the test efficiency and the cooling effect of the device are also significantly improved. Specifically, this device can test multiple devices under test simultaneously, greatly shortening the test cycle. Brief Description of the Drawings

[0024] Figure 1 is the first three-dimensional structural schematic diagram of the present invention.

[0025] Figure 2 is the second three-dimensional structural schematic diagram of the present invention.

[0026] Figure 3 is the top view structural schematic diagram of the present invention.

[0027] Figure 4 is the exploded structural schematic diagram of the water cooling system of the present invention.

[0028] Figure 5 is the three-dimensional structural schematic diagram of the water cooling system of the present invention.

[0029] Figure 6 is the first three-dimensional structural schematic diagram of the heating system of the present invention.

[0030] Figure 7 is the second three-dimensional structural schematic diagram of the heating system of the present invention.

[0031] Figure 8 is the internal structural schematic diagram of the heating system and the control panel of the present invention.

[0032] Figure 9 is the three-dimensional structural schematic diagram of the MOSFET module.

[0033] Figure 10 is the three-dimensional structural schematic diagram of the IGBT module.

[0034] Figure 11 is the schematic diagram of the measurement circuit of the multi-device power cycle test equipment of the present invention.

[0035] In the figure:

[0036] 1 is the main body; 2 is the heating system; 21 is the branch test fixture; 211 is the branch switch; 22 is the auxiliary test fixture; 23 is the measurement terminal; 24 is the hub; 25 is the main switch; 3 is the water cooling system; 31 is the lifting component; 311 is the support frame; 312 is the telescopic drive; 313 is the cooling plate; 314 is the heat conducting plate; 32 is the cold water circulation component; 321 is the water tank; 322 is the circulation pump; 323 is the first pipe; 324 is the second pipe; 325 is the radiator; 326 is the cooling fan; 4 is the control panel; 41 is the measurement protection circuit; 42 is the NI data acquisition card; 43 is the drive circuit; 100 is the IGBT module; 200 is the MOSFET module. Specific Embodiments

[0037] The following combines the accompanying drawings and embodiments to further describe in detail the specific embodiments of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0038] As Figures 6 - 10 shown, the multi-device power cycle test equipment of this embodiment heats the IGBT module 100 and the MOSFET module 200 by passing current through the IGBT module 100 and the MOSFET module 200 to test the aging degree of the IGBT module 100 and the MOSFET module 200, including the main body 1, on which a heating system 2 is provided. The heating system 2 is used to energize and heat the IGBT module 100 and the MOSFET module 200. The heating system 2 includes several branch test fixtures 21 and an auxiliary test fixture 22. Each branch test fixture 21 is connected in parallel by a cable, and the branch test fixture 21 and the auxiliary test fixture 22 are also connected in parallel by a cable. An IGBT module 100 and several MOSFET modules 200 are placed in the branch test fixture 21. The IGBT module 100 and the MOSFET module 200 are connected in series by a circuit. An IGBT module 100 is placed in the auxiliary test fixture 22. Conductive contacts capable of conducting electricity with the IGBT module 100 and the MOSFET module 200 are respectively provided in the branch test fixture 21 and the auxiliary test fixture 22. A water cooling system 3 for dissipating heat from the IGBT module 100 and the MOSFET module 200 is also provided on the main body 1.

[0039] Place the IGBT module 100 and the MOSFET module 200 in the branch test fixture 21 and the auxiliary test fixture 22, and ensure that all conductive contacts are in contact with the devices. Start the heating system 2, and pass current through the IGBT module 100 and the MOSFET module 200 in each test fixture via a cable, so that the IGBT module 100 and the MOSFET module 200 generate heat and the temperature rises. After heating to a certain temperature, disconnect the current of the device under test, start the water cooling system 3, and dissipate the heat of the IGBT module 100 and the MOSFET module 200, so that the IGBT module 100 and the MOSFET module 200 return to the initial temperature. Repeat the heating and heat dissipation processes to simulate the power cycle of the device during actual operation. Through multiple cycle tests, the aging degree of the IGBT module 100 and the MOSFET module 200 can be evaluated, including performance degradation, temperature rise trend, etc. According to the test results, it can be judged whether the device meets the expected life or whether it needs to be replaced.

[0040] The heating system 2 further includes a plurality of branch switches 211 provided on the main body 1 and corresponding to the branch test fixtures 21 respectively for controlling the current flowing into the IGBT module 100 and the MOSFET module 200. When the IGBT module 100 and the MOSFET module 200 in one of the branch test fixtures 21 are powered on for heating, the other branch test fixtures 21 do not have current flowing through them.

[0041] Select one branch test fixture 21 for testing, turn on the corresponding branch switch 211, allow current to flow into the IGBT module 100 and the MOSFET module 200 in this fixture, and perform power-on heating. During the test, the branch switches 211 of the other branch test fixtures 21 remain closed to ensure that the devices in the other branch test fixtures 21 are not affected by the current. After completing one round of testing, turn off the branch switch 211 of the current branch test fixture 21 and wait for the device to cool down to the initial temperature. Repeat the above steps as needed to test the devices in the other branch test fixtures 21. By independently controlling the power-on state of each branch test fixture 21, the mutual interference during the test can be reduced, and the accuracy of the test results can be improved.

[0042] The heating system 2 further includes a hub 24 provided on a side far from the branch switch 211. Each branch test fixture 21 and the auxiliary test fixture 22 are connected to the hub 24 via a cable. A main switch 25 is also provided on the main body 1 near the hub 24. The hub 24 is connected to the main switch 25 via a cable. The main switch 25 and one of the branch switches 211 are connected to the heating current source via a cable.

[0043] The branch test fixture 21 and the auxiliary test fixture 22 are also provided with measurement connection terminals 23, which are electrically connected to the IGBT module 100 and the MOSFET module 200. The main body 1 is also provided with a control panel 4. As Figure 8 shown, the control panel 4 is also internally provided with a measurement protection circuit 41, a NI data acquisition card 42 for collecting data of the IGBT module 100 and the MOSFET module 200, and a drive circuit 43 for driving the heating system 2 and the water cooling system 3 to operate.

[0044] The measurement connection terminals 23 are arranged on the branch test fixture 21 and the auxiliary test fixture 22 and are electrically connected to the IGBT module 100 and the MOSFET module 200. The measurement connection terminals 23 are connected to the control panel 4 through wires. The NI data acquisition card 41 is a high-performance data acquisition device for collecting various data generated by the IGBT module 100 and the MOSFET module 200 during operation. These data can include voltage, current, temperature, time, etc. Among them, the transient thermal impedance curve requires high-precision measurement at 20 MHz, and the other acquisition frequency is 0.5 MHz. It is processed and analyzed through NI LabVIEW or other data acquisition software. The drive circuit 43 is responsible for controlling the operation of the heating system 2 and the water cooling system 3. The drive circuit 43 receives instructions from the control panel 4 and controls the heating power of the heating system 2 and the cooling rate of the water cooling system 3 by adjusting parameters such as current and voltage. After the test is completed, the collected data is imported into the data analysis software for processing and analysis. According to the analysis results, a test report is generated to evaluate the performance status and aging degree of the IGBT module 100 and the MOSFET module 200.

[0045] When the device under test on a certain branch is selected for testing, the system will supply a stable direct current to this branch to heat the device under test on it to the preset temperature. At the same time, other non-test branches remain powered off to avoid unnecessary energy consumption and potential interference. The key advantage of this design is that it allows the system to test multiple devices under test in turn at the same time without waiting for a single device test to be completed before proceeding to the next one. This parallel processing method greatly improves the test efficiency, especially in large-scale device test scenarios, where its advantages are particularly obvious.

[0046] As Figures 1 - 5As shown, the water cooling system 3 includes a lifting component 31 and a cold water circulation component 32. The lifting component 31 includes a plurality of cooling plates 313 that can move up and down and correspond to the branch test fixture 21 and the auxiliary test fixture 22 respectively. A plurality of heat conducting plates 314 that are in contact with and used for heat conduction with the IGBT module 100 and the MOSFET module 200 are further provided at the bottom of the cooling plate 313. The cooling plate 313 also has good heat conduction performance to ensure that the heat received from the heat conducting plate 314 can be quickly transferred to the cold water circulation component 32. The lifting component 31 further includes a lifting structure that can move the cooling plate 313 up and down. The lifting structure includes a support frame 311 fixed to the top of the main body 1 of the machine, and a telescopic driving member 312 is vertically fixed to the top of the support frame 311. The output end of the telescopic driving member 312 is connected to the cooling plate 313.

[0047] The cold water circulation component 32 includes a water tank 321 fixed to the outside of the main body 1 of the machine. A circulation pump 322 is further fixed inside the water tank 321. The circulation pump 322 should have sufficient flow rate and head to ensure that cold water can flow smoothly into the cooling plate 313 and take away the heat generated by the device. The water outlet end of the circulation pump 322 is connected to a first pipe 323. The first pipe 323 should be made of corrosion-resistant and high-temperature-resistant materials to ensure that it will not leak due to corrosion or aging during long-term use. The first pipe 323 is connected to the cooling plate 313. The cooling plate 313 has a cavity for water to flow. When the cold water flows in the cavity, it will absorb the heat transferred from the heat conducting plate 314 from the IGBT module 100 and the MOSFET module 200. The cold water circulation component 32 further includes a second pipe 324 connected to the cooling plate 313. The second pipe 324 should also be made of corrosion-resistant and high-temperature-resistant materials to ensure the reliability of long-term use. The water cooling system 3 further includes a radiator 325 fixed to the water tank 321. The radiator 325 is formed by connecting a plurality of heat conducting fins and heat dissipation tubes. The heat dissipation tubes are arranged in an "S" shape in the heat conducting fins. This design increases the heat dissipation area and improves the heat dissipation efficiency. When the hot water flows in the heat dissipation tubes, it will transfer the heat to the heat conducting fins. The second pipe 324 is connected to one end of the heat dissipation tube, and the other end of the heat dissipation tube is connected to the water tank 321 through a pipe. The cold water circulation component 32 further includes a cooling fan 326 provided on the radiator 325 for dissipating heat from the radiator 325. The cooling fan 326 is used to accelerate the air flow and improve the heat dissipation efficiency.

[0048] Start the circulation pump 322. The circulation pump 322, as the power source of the water cooling system, is responsible for driving the cold water in the water tank 321 into the cooling plate 313. The cooling plate 313 is closely attached to the heat generating components of the IGBT module 100 and the MOSFET module 200 through the built-in heat conducting plate 314. The heat conducting plate 314 is made of a high thermal conductivity material, which can effectively absorb the heat generated by the device under test and transfer it to the water flow passing through the cooling plate 313. The water flow carrying heat passes through the heat dissipation tubes in the radiator 325. The heat dissipation tubes and heat dissipation fins increase the heat dissipation area. A heat dissipation fan 326 is also equipped on the top of the radiator 325. When the heat dissipation fan 326 starts, it generates an air flow to accelerate the air flow around the radiator 325, thereby taking away the heat released by the heat dissipation tubes and heat dissipation fins and achieving efficient heat dissipation.

[0049] A multi-device power cycle test method includes a multi-device power cycle test device in the above solution, and has the following steps.

[0050] S1: Place the IGBT module 100 and the MOSFET module 200 to be tested into the branch test fixture 21 and the auxiliary test fixture 22, and move the cooling plate 313 downward through the telescopic driving member 312. The cooling plate 313 presses the heat conducting plate 314 on the IGBT module 100 and the MOSFET module 200, so that the IGBT module 100 and the MOSFET module 200 are in contact with the conductive contacts.

[0051] S2: After the preparation work is completed, turn on the 15kW / 750A load power supply and the 100 - 500mA measurement current source. The drive circuit 43 outputs a continuously adjustable drive voltage of -10 to +20V according to the test requirements. The control program inside the control panel 4 flexibly adjusts the test mode according to the test requirements. The heating current source continuously outputs a constant current. When one branch is conducting, the other branches are not conducting. The device under test, the MOSFET module 200, is continuously heated. The conduction logic of the IGBT module 100 in the auxiliary test fixture 22 needs to be judged according to whether the output current of the heating current source is greater than the current specification of the MOSFET module 200 under test. If the load current is equal to the current specification of the MOSFET module 200 under test, the drive circuit 43 turns off the current of the IGBT module 100 in the auxiliary test fixture 22. If the load current is greater than the current specification of the MOSFET module 200 under test, the drive circuit 43 adjusts to turn on the IGBT module 100 in the auxiliary test fixture 22 for shunting, so that the current value flowing through the MOSFET module 200 under test just meets its current specification. After the conduction time ends, turn off the IGBT module 100 in the auxiliary test fixture 22, and then turn on another branch for testing. Water cooling is performed on the devices on the branch that has been heated, and information such as the saturation voltage drop and transient thermal impedance at a small current is collected.

[0052] S3: The power cycle test device simultaneously integrates online real-time monitoring functions such as transient thermal impedance curve, thermal resistance, junction temperature, and forward voltage drop. In order to accurately obtain the temperature change of the device under test during the cooling process, the transient thermal impedance curve of the module is obtained through the temperature relationship curve. When the electrical parameters of the device under test exceed the aging index, the control drive chip outputs a turn-off signal and outputs a turn-off acquisition signal.

[0053] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A multi-device power cycle test device, which tests the aging degree of the IGBT module (100) and the MOSFET module (200) by passing current into the IGBT module (100) and the MOSFET module (200) to heat the IGBT module (100) and the MOSFET module (200), characterized in that: The multi-device power cycle test equipment comprises a main body (1), the main body (1) is provided with a heating system (2), the heating system (2) is used to electrically heat the IGBT module (100) and the MOSFET module (200), the heating system (2) comprises a plurality of branch test fixtures (21) and an auxiliary test fixture (22), each branch test fixture (21) is connected in parallel via a cable, and the branch test fixture (21) and the auxiliary test fixture (22) are also connected in parallel via a cable, and an IGBT module (100) is placed in the branch test fixture (21) and a plurality of MOSFET modules (200), the IGBT module (100) and the MOSFET module (200) being connected in series via a circuit, an IGBT module (100) being placed in the auxiliary test fixture (22), the branch test fixture (21) and the auxiliary test fixture (22) being respectively provided with conductive contacts capable of conducting a circuit with the IGBT module (100) and the MOSFET module (200), and the main body (1) being further provided with a water cooling system (3) for dissipating heat from the IGBT module (100) and the MOSFET module (200).

2. A multi-device power cycle test equipment according to claim 1, characterized in that: The heating system (2) further comprises a plurality of branch switches (211) arranged on the main body (1) and corresponding to the branch test fixtures (21) respectively, and used to control the current flowing into the IGBT module (100) and the MOSFET module (200); when the IGBT module (100) and the MOSFET module (200) in one of the branch test fixtures (21) are powered on for heating, no current is passed into the other branch test fixtures (21).

3. A multi-device power cycle test equipment according to claim 2, characterized in that: The heating system (2) further comprises a hub (24) arranged on a side away from the branch switch (211); each branch test fixture (21) and the auxiliary test fixture (22) are connected to the hub (24) via a cable; a main switch (25) is also arranged on the main body (1) near the hub (24); the hub (24) and the main switch (25) are connected via a cable; and the main switch (25) and one of the branch switches (211) are electrically connected to a heating current source via a cable.

4. The multi-device power cycle test equipment according to claim 3, characterized in that: The branch circuit test fixture (21) and the auxiliary test fixture (22) are also provided with measurement terminals (23), and the measurement terminals (23) are electrically connected to the IGBT module (100) and the MOSFET module (200). The main body (1) is also provided with a control panel (4).

5. The multi-device power cycle test equipment according to claim 4, characterized in that: The control panel (4) is also provided with a measurement protection circuit (41), the control panel (4) is also provided with a NI data acquisition card (42) for collecting data of the IGBT module (100) and the MOSFET module (200), and the control panel (4) is also provided with a drive circuit (43) for driving the heating system (2) and the water cooling system (3) to operate.

6. The multi-device power cycle test equipment according to claim 1, characterized in that: The water cooling system (3) comprises a lifting component (31) and a cold water circulation component (32); the lifting component (31) comprises a plurality of cooling plates (313) respectively corresponding to the branch test fixture (21) and the auxiliary test fixture (22) and capable of moving up and down; and a plurality of heat conducting plates (314) respectively contacting the IGBT module (100) and the MOSFET module (200) and used for heat conduction are also arranged at the bottom of the cooling plate (313); the lifting component (31) further comprises a lifting structure capable of moving the cooling plate (313) up and down.

7. The multi-device power cycle test equipment according to claim 6, characterized in that: The lifting structure comprises a support frame (311) fixed on the top of the main body (1), and a telescopic driving member (312) is also vertically fixed on the top of the support frame (311), and the output end of the telescopic driving member (312) is interconnected with the cooling plate (313).

8. The multi-device power cycle test equipment according to claim 6, characterized in that: The cold water circulation component (32) comprises a water tank (321) fixed on the outside of the main body (1), a circulation pump (322) is also fixed inside the water tank (321), a water outlet of the circulation pump (322) is connected to a first pipe (323), the first pipe (323) is connected to a cooling plate (313), the cooling plate (313) has a cavity inside for water flow, the cold water circulation component (32) also comprises a second pipe (324) connected to the cooling plate (313), the water cooling system (3) also comprises a radiator (325) fixed on the water tank (321), the radiator (325) is connected to a heat dissipation pipe by using a plurality of heat conducting plates, the heat dissipation pipe is arranged in an "S" shape in the heat conducting plates, the second pipe (324) is connected to one end of the heat conducting pipe, and the other end of the heat conducting pipe is connected to the water tank (321) through a pipe.

9. The multi-device power cycle test equipment according to claim 8, characterized in that: The cold water circulation component (32) also includes a cooling fan (326) disposed on the radiator (325) for dissipating heat from the radiator (325).

10. A multi-device power cycle test method, using a multi-device power cycle test device according to any one of claims 1 to 9, comprising the following steps, characterized in that: S1: placing the IGBT module (100) and MOSFET module (200) to be tested into the branch circuit test fixture (21) and the auxiliary test fixture (22), and moving the cooling plate (313) downward by means of the telescopic driving member (312), so that the cooling plate (313) presses the heat conducting plate (314) onto the IGBT module (100) and the MOSFET module (200), so that the IGBT module (100) and the MOSFET module (200) are in contact with the conductive contacts; S2: After the preparation work is completed, the 15kW / 750A load power supply and the 100-500mA measurement current source are turned on. The drive circuit (43) outputs a continuously adjustable drive voltage of -10 to +20V according to the test requirements. The control program inside the control panel (4) flexibly adjusts the test mode according to the test requirements. The heating current source maintains a constant current output. When one of the branches is turned on, the other branches are not turned on. The MOSFET module (200) of the device under test is continuously heated. The conduction logic of the IGBT module (100) in the auxiliary test fixture (22) needs to be adjusted according to the heating current. Whether the source output current is greater than the current specification of the MOSFET module (200) to be tested is judged. If the load current is equal to the current specification of the MOSFET module (200) to be tested, the drive circuit (43) turns off the current of the IGBT module (100) in the auxiliary test fixture (22). If the load current is greater than the current specification of the MOSFET module (200) to be tested, the drive circuit (43) adjusts and turns on the IGBT module (100) in the auxiliary test fixture (22) for shunting, so that the current value flowing through the MOSFET module (200) to be tested just meets its current specification. When the on time ends, the IGBT module (100) in the auxiliary test fixture (22) is turned off, and then another branch is turned on for testing, and the device on the branch that has been heated is water-cooled to collect information such as saturation voltage drop and transient thermal impedance under low current. S3: The power cycle test device integrates online real-time monitoring functions such as transient thermal impedance curve, thermal resistance, junction temperature, and forward voltage drop. In order to accurately obtain the temperature change of the module under test during the cooling process, the transient thermal impedance curve of the module is obtained through the temperature relationship curve. When the electrical parameters of the device under test exceed the aging index, the driver chip is controlled to output a shutdown signal and output a shutdown acquisition signal.

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