An IGBT test circuit, method and device

Abstract

The present application relates to the technical field of module testing, and specifically relates to an IGBT testing circuit, method and device, which comprises a power supply unit, a testing control unit, a state indication unit and a testing docking unit; the power supply unit is provided with an AC input end and a DC output end, and is used for outputting a constant DC voltage; the testing docking unit is provided with a plurality of testing ports, each testing port is electrically connected with a collector, an emitter and a gate of an IGBT to be tested; the testing control unit is electrically connected with the power supply unit and the testing docking unit; the state indication unit is connected in series in a testing control loop and an IGBT main current loop to be tested, and is used for directly displaying the on-off state of the loop. The present application sets four groups of testing ports and arranges them in groups, and is specially used for corresponding to three types of electrodes of IGBT, i.e. gate, collector and emitter, and does not need to repeatedly switch detection probes, the wiring mode is fixed and the operation is simple, the requirement for professional ability of operators is reduced, the wiring efficiency is effectively improved, and the present application is suitable for a fast detection scene.

Description

Technical Field

[0001] This invention relates to the field of module testing technology, and specifically to an IGBT testing circuit, method, and apparatus. Background Technology

[0002] Insulated-gate bipolar transistors (IGBTs), as core power devices in the field of power electronics, are widely used in equipment such as frequency converters, switching power supplies, and new energy vehicles. Their turn-on and turn-off performance directly determines the reliability of the entire system. In device selection, maintenance and testing, and failure analysis scenarios, it is necessary to quickly and accurately determine whether the IGBT is intact.

[0003] Currently, the mainstream IGBT testing methods in the industry mainly rely on digital multimeters or professional power device testers. These existing testing methods have the following significant shortcomings:

[0004] The operation is cumbersome and inefficient: multimeter testing requires switching between ranges multiple times and repeatedly touching the pins, making it time-consuming to test a single device and unable to meet the needs of batch or rapid on-site testing; the results are vague and prone to misjudgment: the device status can only be indirectly inferred from the impedance value, and it cannot intuitively reflect the conduction and turn-off capabilities of the IGBT under actual driving, making it difficult to identify faults such as gate charge retention failure and partial breakdown; professional testers are bulky and rely on mains power or dedicated power supplies, making them difficult to use in equipment repair sites, outdoor debugging, and other scenarios; the cost is high and difficult to popularize: professional power device testers usually cost several thousand to tens of thousands of yuan, which is unaffordable for small and medium-sized repair enterprises or individual users, limiting the promotion of efficient testing methods.

[0005] Therefore, it is necessary to invent an IGBT testing circuit, method, and apparatus to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide an IGBT testing circuit, method, and apparatus. By setting up a corresponding circuit structure, an IGBT testing device with simple structure, convenient operation, intuitive results, and low cost is provided, which can quickly, intuitively, and safely test the performance of IGBTs.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] An IGBT test circuit is provided, including a power supply unit, a test control unit, a status indication unit, and a test docking unit; the power supply unit is provided with an AC input terminal and a DC output terminal for outputting a constant DC voltage;

[0009] The test docking unit is provided with several test ports, each of which is electrically connected to the collector, emitter, and gate of the IGBT under test.

[0010] The test control unit is electrically connected to the power supply unit and the test docking unit, respectively, and is used to apply a driving level to the gate of the IGBT under test or to discharge the gate charge.

[0011] The status indicator units are connected in series in the test control loop and the main current loop of the IGBT under test, respectively, to visually display the loop on / off status.

[0012] As a preferred embodiment of an IGBT test circuit, the test docking unit includes four alligator clip test ports, which are divided into a first port group and a second port group. The first port group has two test ports connected in parallel and facing the gate of the IGBT under test. The second port group has two test ports respectively facing the collector and emitter of the IGBT under test.

[0013] As a preferred embodiment of an IGBT test circuit, the power supply unit includes a power plug, a fuse, a step-down transformer, a rectifier bridge, a filter capacitor, and a voltage regulator integrated circuit. The power plug, fuse, and step-down transformer are connected in series. The output terminal of the step-down transformer is connected to the rectifier bridge. The output terminal of the rectifier bridge is connected in parallel with a filter capacitor. The two ends of the filter capacitor are connected to the voltage regulator integrated circuit.

[0014] As a preferred embodiment of an IGBT test circuit, the power plug is connected to 220V AC mains power, the step-down transformer outputs 18V AC power, and the voltage regulator integrated circuit outputs 15V DC voltage.

[0015] As a preferred embodiment of an IGBT test circuit, the test control unit includes a trigger button, a turn-off button, and two sets of current-limiting resistors. The trigger button and a set of current-limiting resistors are connected in series to the corresponding gate test port to form a gate drive circuit. The second circuit terminal of the trigger button is connected in series with the second current-limiting resistor and the trigger indicator light and then grounded. One end of the turn-off button is connected to the gate test port, and the other end is grounded, which is used to directly ground the gate of the IGBT under test to discharge the gate charge.

[0016] As a preferred embodiment of an IGBT test circuit, the status indicator unit includes a trigger indicator and an on indicator; the trigger indicator is connected in series in the circuit where the trigger button is located, and the on indicator is connected in series with the main current circuit formed by the collector and emitter of the IGBT under test.

[0017] An IGBT testing device is provided, including a housing and an IGBT testing circuit integrated within the housing; the housing externally exposes a power plug, a trigger button, a turn-off button, a trigger indicator light, an on indicator light, and all test ports of the test docking unit.

[0018] An IGBT testing method is provided, applied to the IGBT testing circuit according to any one of claims 1 to 6, comprising the following steps:

[0019] S1. Connect the circuit to each electrode of the IGBT under test through the test port of the test docking unit, and connect the mains power to enable the power supply unit to output DC voltage normally.

[0020] S2. The control unit applies a drive level and combines it with the signal from the status indicator unit to complete the conduction performance test of the IGBT under test.

[0021] S3. Remove the drive level and combine it with the signal from the status indicator unit to complete the gate charge retention performance detection of the IGBT under test.

[0022] S4. The control unit discharges the gate charge of the IGBT under test, and combined with the status indicator light status, detects the turn-off performance of the IGBT under test.

[0023] As a preferred solution for IGBT testing, in step S2, when the trigger indicator and the turn-on indicator light are lit simultaneously, it is determined that the IGBT under test is in a normal conduction state.

[0024] In step S3, if the on indicator light remains lit after the drive level is removed, it is determined that the gate charge retention performance of the IGBT under test is normal.

[0025] As a preferred method for IGBT testing, in step S4, after the gate charge is discharged, if the state of the turn-on indicator light changes, it is determined that the IGBT under test is in a normal turn-off state; if the state of the turn-on indicator light does not change, it is determined that the IGBT under test has a shoot-through fault.

[0026] The beneficial effects of this invention are that by integrating power supply, control, status indication and test docking functions into an integrated circuit, the whole is composed of general discrete components and conventional integrated circuits. The circuit architecture is simple, and there is no need for complex special chips and precision sampling devices. The hardware procurement, assembly and maintenance costs are low, and it is easy to mass-produce and promote application.

[0027] Four test ports are set up and grouped to specifically correspond to the three types of electrodes of IGBT: gate, collector, and emitter. There is no need to repeatedly switch test probes. The wiring method is fixed and the operation is simple, reducing the requirements for the professional skills of operators, effectively improving wiring efficiency, and adapting to the rapid testing scenario on site.

[0028] Breaking through the limitations of traditional multimeters that can only perform static resistance measurements, this device can comprehensively test the conduction capability, charge retention capability, and turn-off capability of IGBTs. It can accurately identify various typical faults such as open circuit, gate failure, and shoot-through breakdown, with a wide testing coverage and high reliability of results. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0030] Figure 1 This is the assembly circuit diagram of the present invention.

[0031] Figure 2 This is the circuit diagram of the triggering part of the present invention.

[0032] Figure 3 This is a circuit diagram of the shutdown part of the present invention.

[0033] Figure 4 This is a power supply flowchart for the IGBT testing device of the present invention.

[0034] Figure 5 This is a flowchart of the IGBT conduction performance test of the present invention.

[0035] Figure 6 This is a flowchart of the IGBT conduction and retention performance test of the present invention.

[0036] Figure 7 This is a flowchart of the IGBT turn-off performance test of the present invention. Detailed Implementation

[0037] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0038] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0039] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0040] refer to Figures 1 to 7 This invention provides an IGBT test circuit, including a power supply unit, a test control unit, a status indication unit, and a test docking unit; the power supply unit is provided with an AC input terminal and a DC output terminal for outputting a constant DC voltage;

[0041] The test docking unit is provided with several test ports, each of which is electrically connected to the collector, emitter, and gate of the IGBT under test.

[0042] The test control unit is electrically connected to the power supply unit and the test docking unit, respectively, and is used to apply a driving level to the gate of the IGBT under test or to discharge the gate charge.

[0043] The status indicator units are connected in series in the test control loop and the main current loop of the IGBT under test, respectively, to visually display the loop on / off status.

[0044] The power supply unit provides a stable and safe DC power supply: by stepping down, rectifying, filtering and regulating, it converts 220V AC mains power to 15V DC, avoiding high voltage risks and adapting to the gate drive requirements of IGBTs.

[0045] Features overload and short circuit protection: The fuse can cut off the AC input in case of overcurrent / short circuit, protecting the downstream circuit and the device under test.

[0046] Constant voltage output: The voltage regulator integrated circuit eliminates ripple, providing a reliable operating voltage for testing and avoiding voltage fluctuations from interfering with the test results.

[0047] The test docking unit includes four alligator clip test ports, which are divided into a first port group and a second port group. The first port group has two test ports connected in parallel and facing the gate of the IGBT under test. The second port group has two test ports respectively facing the collector and emitter of the IGBT under test. Figure 1 As shown, the alligator clip test ports include CLIP1, CLIP2, CLIP3, and CLIP4. CLIP1 and CLIP2 are both connected to the IGBT gate and are connected in parallel in the circuit, jointly clamping the gate pin. CLIP3 is connected to the IGBT collector. CLIP4 is connected to the IGBT emitter. The first port group consists of CLIP1 and CLIP2, and the second port group consists of CLIP3 and CLIP4.

[0048] The power supply unit includes a power plug, a fuse, a step-down transformer, a rectifier bridge, a filter capacitor, and a voltage regulator integrated circuit. The power plug, fuse, and step-down transformer are connected in series. The output terminal of the step-down transformer is connected to the rectifier bridge. The output terminal of the rectifier bridge is connected in parallel with the filter capacitor. The two ends of the filter capacitor are connected to the voltage regulator integrated circuit.

[0049] The power plug is connected to 220V AC mains power, the step-down transformer outputs 18V AC power, and the voltage regulator integrated circuit outputs 15V DC voltage.

[0050] The test control unit includes a trigger button, a turn-off button, and two sets of current-limiting resistors. The trigger button and a set of current-limiting resistors are connected in series to the corresponding gate test port to form a gate drive circuit. The second circuit terminal of the trigger button is connected in series with the second current-limiting resistor and the trigger indicator light and then grounded. One end of the turn-off button is connected to the gate test port, and the other end is grounded, which is used to directly ground the gate of the IGBT under test to discharge the gate charge.

[0051] The status indication unit includes a trigger indicator and an on indicator; the trigger indicator is connected in series in the circuit where the trigger button is located, and the on indicator is connected in series with the main current circuit formed by the collector and emitter of the IGBT under test.

[0052] An IGBT testing device includes a housing and an IGBT testing circuit integrated within the housing. The housing exterior exposes a power plug, trigger button, turn-off button, trigger indicator light, turn-on indicator light, and all test ports of the test docking unit. By integrating the testing circuit into a closed housing and arranging the power plug, operation buttons, status indicator lights, and test ports on the exterior, portable, safe, and visualized IGBT performance testing is achieved. This not only effectively improves the device's anti-interference capability and lifespan but also significantly lowers the testing operation threshold, enabling non-professionals to quickly test IGBT conduction, gate charge retention, and turn-off performance, making it particularly suitable for rapid on-site screening and fault location scenarios.

[0053] An IGBT testing method, applied to the aforementioned IGBT test circuit, includes the following steps:

[0054] S1. Connect the circuit to each electrode of the IGBT under test through the test port of the test docking unit, and connect the mains power to enable the power supply unit to output DC voltage normally; Function: Establish the electrical connection between the test circuit and the IGBT under test, and provide a stable DC power supply for subsequent tests.

[0055] S2. The control and test control unit applies a drive level, and in conjunction with the signal from the status indicator unit, completes the conduction performance test of the IGBT under test; function: apply a drive signal to the IGBT gate to verify its conduction capability.

[0056] S3. Remove the drive level and, in conjunction with the signal from the status indicator unit, complete the gate charge retention performance test of the IGBT under test. Function: Verify the IGBT's gate charge retention capability, indirectly reflecting the gate insulation performance and leakage current level. After removing the drive, if the on indicator light remains lit, it indicates that the gate charge has not leaked rapidly, the IGBT remains in the conducting state, and the gate charge retention performance is good. If the indicator light quickly goes out, it indicates severe gate charge leakage, and the device has a risk of gate leakage or insulation failure.

[0057] S4. The control unit discharges the gate charge of the IGBT under test, and the status indicator light status is used to test the IGBT's turn-off performance. Purpose: To actively discharge the gate charge, verify the IGBT's turn-off capability, and troubleshoot shoot-through faults. After discharge, the turn-on indicator light goes out, proving that the IGBT can be reliably turned off and its turn-off performance is normal; if the indicator light remains on, it indicates that the IGBT cannot be turned off and there is a shoot-through fault (such as collector-emitter breakdown or device damage).

[0058] In step S2, when the trigger indicator and the turn-on indicator light are lit at the same time, it is determined that the conduction state of the IGBT under test is normal.

[0059] In step S3, if the on indicator light remains lit after the drive level is removed, it is determined that the gate charge retention performance of the IGBT under test is normal.

[0060] In step S4, after the gate charge is discharged, if the state of the turn-on indicator light changes, it is determined that the IGBT under test is in a normal turn-off state; if the state of the turn-on indicator light does not change, it is determined that the IGBT under test has a shoot-through fault.

[0061] The IGBT testing method of this invention provides intuitive feedback on the IGBT's conduction, charge retention, and turn-off states through indicator lights, achieving instrument-free, visual, and rapid IGBT performance testing. This effectively reduces the testing threshold and cost, and improves on-site testing efficiency. At the same time, the standardized procedure design avoids human error and improves the reliability and consistency of test results, making it suitable for scenarios such as incoming IGBT inspection, maintenance screening, and teaching demonstrations.

[0062] refer to Figure 1-3 The functions of each component in the final assembly circuit diagram are briefly described below:

[0063] J1: Power plug for device, 220VAC input;

[0064] F: Transformer input fuse;

[0065] T: Transformer, 220V / 18V;

[0066] D1: Rectifier bridge;

[0067] C1-C4: Filter capacitors;

[0068] IC1: 15V voltage regulator integrated circuit;

[0069] S1: IGBT trigger button;

[0070] S2: IGBT turn-off button;

[0071] R1-R2: Current-limiting resistors;

[0072] LAMP1: Power indicator light;

[0073] CLI1-CLI4: Alligator clips, test clamps;

[0074] IGBT.1: IGBT to be tested.

[0075] Example 1: Overall Structure and Circuit Connection of IGBT Testing Device

[0076] This embodiment provides an IGBT testing device for detecting the conduction, charge retention, and turn-off performance of an insulated gate bipolar transistor. The device consists of a power supply unit, a control unit, a status indication unit, and a test clamping unit, with each unit connected according to an electrical schematic diagram.

[0077] This device operates on a standard 220V AC mains power supply. The circuit components are connected sequentially according to the schematic diagram: power plug J1 serves as the external input terminal, connected in series with fuse F to the primary winding of step-down transformer T; the secondary winding of transformer T outputs 18V AC power, which is connected to the AC input terminal of rectifier bridge D1; filter capacitors C1 and C2 are connected in parallel to the DC output terminal of rectifier bridge D1 to achieve voltage filtering; the filtered voltage is connected to the input terminal of 15V voltage regulator integrated circuit IC1, and filter capacitors C3 and C4 are connected in parallel to the output terminal of IC1, ultimately outputting a stable 15V DC voltage to provide power for all subsequent test circuits.

[0078] The regulated output terminal is connected to trigger button S1, turn-off button S2, current-limiting resistors R1 and R2, trigger indicator D1, and turn-on indicator LAMP1, respectively. Trigger button S1 is connected in series with current-limiting resistor R1 and then connected to the first alligator clip CLI1. One end of turn-off button S2 is connected to circuit ground, and the other end is connected to the second alligator clip CLI2. One end of turn-on indicator LAMP1 is connected to the 15V DC positive terminal, and the other end is connected to the third alligator clip CLI3. The fourth alligator clip CLI4 is connected to the circuit common ground. Among them, CLI1 and CLI2 are connected to the gate G of the IGBT under test, CLI3 is connected to the collector C of the IGBT under test, and CLI4 is connected to the emitter E of the IGBT under test. Current-limiting resistors R1 and R2 are used to limit the loop current and prevent overcurrent damage to the IGBT and circuit components under test. Fuse F provides short-circuit and overload protection for the whole machine.

[0079] Example 2: Routine testing procedure for the device (normal IGBT testing)

[0080] When using this device to test a working IGBT, follow these steps:

[0081] Wiring and fixing: Insert the power plug J1 into a 220V AC power supply, and use four alligator clips to clamp the corresponding pins of the IGBT under test: CLI1 and CLI2 clamp the gate G, CLI3 clamp the collector C, and CLI4 clamp the emitter E, ensuring that the wiring is secure and the contact is good.

[0082] Trigger-on-conductance test: Pressing the trigger button S1, a 15V drive voltage is applied to the IGBT gate through S1 and R1, and the trigger indicator D1 (red LED) lights up; the IGBT conducts normally under the action of the gate drive voltage, a path is formed between the collector and emitter, and the on-in indicator LAMP1 lights up simultaneously. Releasing the trigger button S1, the charge stored in the IGBT gate can be maintained autonomously, the device continues to maintain the conducting state, and LAMP1 remains constantly lit, proving that the IGBT's conduction function and charge retention function are normal.

[0083] Turn-off performance test: With the current wiring status maintained, press the turn-off button S2. The IGBT gate will quickly discharge the stored charge to ground through CLI2 and S2, and the gate drive voltage will disappear. A normal IGBT will turn off immediately, the circuit between the collector and emitter will be broken, and the on indicator light LAMP1 will turn off, proving that the IGBT turn-off function is normal.

[0084] Test complete: Release all buttons, remove the four alligator clips, disconnect the 220V AC power, and the single test process is complete.

[0085] Example 3: Typical Fault IGBT Detection and Judgment Example

[0086] Based on the indicator light status, IGBTs with different fault types are detected and judged, as follows:

[0087] Fault 1: IGBT gate damage / collector-emitter open circuit. After completing the wiring and pressing the trigger button S1, the trigger indicator D1 lights up normally, but the turn-on indicator LAMP1 remains off. This indicates that a drive signal has been input to the gate, but the IGBT cannot form a conduction loop, indicating that the IGBT has an open circuit or gate failure.

[0088] Fault 2: IGBT gate charge retention capability fails. When the trigger button S1 is pressed, both D1 and LAMP1 light up normally; the moment S1 is released, LAMP1 immediately turns off. This indicates that the IGBT can only conduct when a continuous drive voltage is applied, and the gate cannot store charge, thus the charge retention performance fails.

[0089] Fault 3: IGBT shoot-through failure, unable to turn off. After triggering turn-on, LAMP1 lights up normally. Pressing the turn-off button S2, the gate charge discharges normally, but LAMP1 remains lit and does not turn off. This indicates that the IGBT collector and emitter are permanently connected, the device is short-circuited, and it loses its turn-off capability.

[0090] By integrating power supply, control, status indication, and test docking functions into a single circuit, the entire circuit is composed of general-purpose discrete components and conventional integrated circuits. The circuit architecture is simple, requiring no complex dedicated chips or precision sampling devices, resulting in low hardware procurement, assembly, and maintenance costs, and facilitating mass production and widespread application.

[0091] The circuit has a built-in integrated power supply unit for step-down, rectification, filtering and voltage regulation. It can be directly connected to the 220V AC mains power and automatically convert it to the low-voltage DC working voltage required for testing. No additional external power supply is required. The equipment is highly independent and portable, and is suitable for various outdoor and on-site mobile operations such as elevator maintenance and inverter repair.

[0092] Four groups of test ports are set up and arranged in a grouped layout, specifically corresponding to the three types of electrodes of IGBT: gate, collector, and emitter. There is no need to repeatedly switch test probes. The wiring method is fixed and the operation is simple, reducing the professional ability requirements of operators and effectively improving wiring efficiency. It is suitable for rapid on-site testing scenarios. It breaks through the limitation of traditional multimeters that can only measure static resistance. It can comprehensively test the conduction capability, charge retention capability, and turn-off capability of IGBT. It can accurately identify various typical faults such as open circuit, gate failure, and shoot-through breakdown. The test coverage is wide and the results are highly reliable.

[0093] The power supply circuit is equipped with fuses to provide AC side overload and short-circuit protection. The test control unit is equipped with two sets of current-limiting resistors to limit the current in the gate drive circuit and the gate discharge circuit, respectively. This effectively suppresses inrush current, protecting the IGBT under test from damage due to overcurrent and improving the operational stability and service life of the test circuit itself.

[0094] It should be stated that the above-described specific embodiments are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art should understand that various modifications, equivalent substitutions, and variations can be made to the present invention. However, such variations, as long as they do not depart from the spirit of the present invention, should be within the scope of protection of the present invention. Furthermore, some terminology used in this specification and claims is not limiting, but merely for ease of description.

Claims

1. An IGBT test circuit, characterized in that: It includes a power supply unit, a test control unit, a status indication unit, and a test docking unit; the power supply unit is equipped with an AC input terminal and a DC output terminal for outputting a constant DC voltage; The test docking unit is provided with several test ports, each of which is electrically connected to the collector, emitter, and gate of the IGBT under test. The test control unit is electrically connected to the power supply unit and the test docking unit, respectively, and is used to apply a driving level to the gate of the IGBT under test or to discharge the gate charge. The status indicator units are connected in series in the test control loop and the main current loop of the IGBT under test, respectively, to visually display the loop on / off status.

2. The IGBT test circuit according to claim 1, characterized in that: The test docking unit includes four alligator clip test ports, which are divided into a first port group and a second port group. The first port group has two test ports connected in parallel and facing the gate of the IGBT under test. The second port group has two test ports respectively facing the collector and emitter of the IGBT under test.

3. The IGBT test circuit according to claim 1, characterized in that: The power supply unit includes a power plug, a fuse, a step-down transformer, a rectifier bridge, a filter capacitor, and a voltage regulator integrated circuit. The power plug, fuse, and step-down transformer are connected in series. The output terminal of the step-down transformer is connected to the rectifier bridge. The output terminal of the rectifier bridge is connected in parallel with the filter capacitor. The two ends of the filter capacitor are connected to the voltage regulator integrated circuit.

4. The IGBT test circuit according to claim 3, characterized in that: The power plug is connected to 220V AC mains power, the step-down transformer outputs 18V AC power, and the voltage regulator integrated circuit outputs 15V DC voltage.

5. The IGBT test circuit according to claim 1, characterized in that: The test control unit includes a trigger button, a turn-off button, and two sets of current-limiting resistors. The trigger button and a set of current-limiting resistors are connected in series to the corresponding gate test port to form a gate drive circuit. The second circuit terminal of the trigger button is connected in series with the second current-limiting resistor and the trigger indicator light and then grounded. One end of the turn-off button is connected to the gate test port, and the other end is grounded, which is used to directly ground the gate of the IGBT under test to discharge the gate charge.

6. The IGBT test circuit according to claim 5, characterized in that: The status indication unit includes a trigger indicator and an on indicator; the trigger indicator is connected in series in the circuit where the trigger button is located, and the on indicator is connected in series with the main current circuit formed by the collector and emitter of the IGBT under test.

7. An IGBT testing device, characterized in that: The device includes a housing and the IGBT test circuit according to any one of claims 1 to 6 integrated within the housing; the housing also includes an exposed power plug, trigger button, off button, trigger indicator light, on indicator light, and all test ports of the test docking unit.

8. An IGBT testing method, characterized in that: The IGBT test circuit according to any one of claims 1 to 6 includes the following steps: S1. Connect the circuit to each electrode of the IGBT under test through the test port of the test docking unit, and connect the mains power to enable the power supply unit to output DC voltage normally. S2. The control unit applies a drive level and combines it with the signal from the status indicator unit to complete the conduction performance test of the IGBT under test. S3. Remove the drive level and combine it with the signal from the status indicator unit to complete the gate charge retention performance detection of the IGBT under test. S4. The control unit discharges the gate charge of the IGBT under test, and combined with the status indicator light status, detects the turn-off performance of the IGBT under test.

9. The IGBT testing method according to claim 8, characterized in that: In step S2, when the trigger indicator and the turn-on indicator light are lit at the same time, it is determined that the conduction state of the IGBT under test is normal. In step S3, if the on indicator light remains lit after the drive level is removed, it is determined that the gate charge retention performance of the IGBT under test is normal.

10. The IGBT testing method according to claim 8, characterized in that: In step S4, after the gate charge is discharged, if the state of the turn-on indicator light changes, it is determined that the IGBT under test is in a normal turn-off state; if the state of the turn-on indicator light does not change, it is determined that the IGBT under test has a shoot-through fault.

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