Double-pulse test auxiliary device

Abstract

The utility model discloses a double-pulse test auxiliary device, relates to the technical field of power electronics, and improves the double-pulse test efficiency. The device comprises input and output equipment, a main control board card, a controllable switch, an output selection circuit and n input selection circuits, wherein n is greater than or equal to 1; the input and output equipment is connected with the main control board card; the input end of the controllable switch is connected with the low-voltage power supply, the output end is connected with the to-be-tested power module, and the control end is connected with the main control board card; the to-be-tested power module comprises m power switch devices and driving circuits arranged corresponding to the power switch devices respectively, and m is greater than or equal to 2; the output selection circuit is provided with a control end, a single-path input end and m-path output ends, the input end of the output selection circuit is connected with the signal generator, the m-path output ends are connected into the m driving circuits one to one, and the control end of the output selection circuit is connected with the main control board card; the input selection circuit is provided with a control end, m input ends and a single output end, the m input ends are connected to the m power switch devices in a one-to-one mode, the output end of the input selection circuit is connected with the measuring instrument, and the control end of the input selection circuit is connected with the main control board card.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, and more specifically to a double pulse test auxiliary device. Background Art

[0002] Double pulse testing is a test method for evaluating the electrical characteristics of power switching devices (such as IGBT, SiC-MOSFET and other power switching devices). For a power module containing multiple power switching devices, it is necessary to perform double pulse testing on each power switching device contained in the power module one by one. In the prior art, testers need to frequently disconnect and wire between the measuring instrument (i.e., the double pulse test device) and different power switching devices, which is cumbersome and inefficient. Utility Model Content

[0003] In view of this, the utility model provides a double pulse test auxiliary device to improve the double pulse test efficiency.

[0004] A double pulse test auxiliary device, comprising: an input and output device, a main control board, a controllable switch, an output selection circuit and n input selection circuits, n≥1;

[0005] Wherein, the input and output devices are connected to the main control board to realize human-computer interaction;

[0006] The input end of the controllable switch is connected to a low-voltage power supply, the output end of the controllable switch is connected to a power module to be tested, and the control end of the controllable switch is connected to the main control board; the power module to be tested includes m power switch devices and a driving circuit respectively arranged for each power switch device, m≥2;

[0007] The output selection circuit has a control end, a single input end and m output ends, the input end of which is connected to a signal generator, the m output ends of which are connected to the m driving circuits one-to-one, and the control end of which is connected to the main control board; the output selection circuit is used to select one of the m output ends to be connected to the input end under the control of the main control board, and output a double-pulse driving signal for controlling the on and off of one power switch device;

[0008] The input selection circuit has a control end, m-way input ends and a single-way output end, wherein the m-way input ends are connected one-to-one to the m power switch devices, the output end is connected to the measuring instrument, and the control end is connected to the main control board; the input selection circuit is used to select one of the m-way input ends to be connected to the output end under the control of the main control board, collect and output the signal to be tested of one power switch device; when n≥2, different input selection circuits are used to collect different signals to be tested.

[0009] Optionally, the output selection circuit further includes an (m+1)th output terminal;

[0010] The m+1th output end is connected to the main control board and is used to feed back the double-pulse driving signal to the main control board.

[0011] Optionally, the signal to be measured includes a gate voltage of a power switch device;

[0012] The double pulse test auxiliary device also includes: a spare positive and negative power supply module;

[0013] The backup positive and negative power supply modules are used to replace the positive and negative power supply modules of the power switch device itself when the gate voltage of the power switch device is abnormal, so as to ensure that the drive circuit outputs a standard gate turn-on voltage or gate turn-off voltage to the power switch device.

[0014] Optionally, the shell of the double pulse test auxiliary device is made of insulating material.

[0015] Optionally, the double pulse test auxiliary device further includes: an alarm connected to the main control board and a temperature sensor for collecting temperature information of the power module to be tested, and an output end of the temperature sensor is connected to the main control board.

[0016] Optionally, the double pulse test auxiliary device further comprises: an alarm connected to the main control board, and a position sensor and / or a quality sensor connected to the main control board;

[0017] The position sensor is used to measure the position of the double-pulse test auxiliary device; the mass sensor is used to measure the load-bearing capacity of the double-pulse test auxiliary device.

[0018] Optionally, a switch circuit is provided between each output terminal and input terminal of the output selection circuit;

[0019] The switch circuit includes: a current limiting resistor R1, a diode D1, a switch tube Q1 and a normally open relay K1;

[0020] Among them, the cathode of the diode D1 is connected to the power supply, and the anode of the diode D1 is connected to the input electrode of the switch tube Q1; the output electrode of the switch tube Q1 is grounded, and the control electrode of the switch tube is connected to the main control board through the current limiting resistor R1; the coil of the normally open relay K1 is connected in parallel with the diode D1; and the normally open contact of the normally open relay K1 is connected to the main circuit.

[0021] Optionally, the switch circuit is provided between each input terminal and output terminal of the input selection circuit.

[0022] Optionally, the switch tube Q1 is an NPN transistor.

[0023] Optionally, the input-output device is a touch screen.

[0024] It can be seen from the above technical scheme that the main control board in the utility model automatically starts testing after the power module to be tested is powered on according to the test requirements input by the tester, including: controlling the output selection circuit to output a dual-pulse drive signal for controlling the on and off of a power switching device, and controlling the input selection circuit to only collect and output the test signal of the power switching device, so as to assist the measuring instrument to complete the dual-pulse test of the power switching device; when the next power switching device needs to be tested, the tester only needs to input new test requirements, and the tester does not need to perform wiring operations between the measuring instrument and different power switching devices, thereby improving the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A circuit schematic diagram of a double pulse test auxiliary device disclosed in an embodiment of the utility model;

[0027] Figure 2 A circuit schematic diagram of another double pulse test auxiliary device disclosed in an embodiment of the utility model;

[0028] Figure 3 It is a main perspective view of a double pulse test auxiliary device disclosed in an embodiment of the utility model;

[0029] Figure 4 The present invention is a circuit diagram of a controllable switch disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] For the purpose of reference and clarity, the technical terms, abbreviations or acronyms used below are summarized as follows:

[0031] IGBT: Insulated Gate Bipolar Transistor, insulated gate bipolar transistor;

[0032] SiC-MOSFET: Silicon Carbide Metal-Oxide-Semiconductor Field-EffectTransistor, silicon carbide metal oxide semiconductor field effect transistor;

[0033] PWM: Pulse Width Modulation, pulse width modulation;

[0034] LCD: Liquid Crystal Display.

[0035] By reading the specifications provided by the device manufacturers, we can understand the main parameters of power semiconductor devices (such as IGBT, SiC-MOSFET and other power switching devices), but the parameters described in the specifications are test data obtained under specific conditions, which may not represent the actual performance of power semiconductor devices in actual applications. Therefore, some parameters described in the specifications cannot be used directly. Manufacturers need to conduct more accurate tests on the electrical characteristics of each power switching device contained in the power module (such as three-phase inverter, three-phase rectifier and other power modules) in the early stage of power module design.

[0036] Double pulse test is a commonly used test method for evaluating the electrical characteristics of power switching devices. For a power module containing multiple power switching devices, it is necessary to perform double pulse test on each power switching device contained in the power module one by one. Taking a three-phase inverter as an example, the three phases U, V, and W of the three-phase inverter are three half bridges, each half bridge consists of two bridge arms, an upper bridge arm and a lower bridge arm, and each bridge arm has a power switching device such as SiC-MOSFET. In the early stage of the three-phase inverter design, it is necessary to perform double pulse test on the U phase upper bridge arm, U phase lower bridge arm, V phase upper bridge arm, V phase lower bridge arm, W phase upper bridge arm and W phase lower bridge arm of the three-phase inverter. The test content for each SiC-MOSFET usually includes: sending Vpwm signal and collecting and analyzing the Vgs, Vds and Ids signals of SiC-MOSFET, so as to understand the switching characteristics of SiC-MOSFET and the reverse recovery characteristics of the body diode or fast recovery diode connected in parallel with it. The meaning of each signal is as follows:

[0037] 1. Vgs: The voltage between the gate and source of the SiC-MOSFET;

[0038] 2. Vds: The voltage between the drain and source of the SiC-MOSFET;

[0039] 3.Ids: The current between the drain and source of the SiC-MOSFET;

[0040] 4.Vpwm: Test input dual pulse drive signal, which is two-way PWM signal.

[0041] In the prior art, in order to implement a double pulse test on each power switch device included in the power module one by one, the tester needs to frequently disconnect the wiring between the measuring instrument and different power switch devices (i.e., frequently move the test probe), and because the disconnection operation must be performed when the power module to be tested is powered off, the power supply of the power module to be tested needs to be frequently turned off and on during the double pulse test. These factors lead to the following disadvantages in the existing double pulse test process:

[0042] 1. The operation is cumbersome and inefficient;

[0043] 2. The test point may fall off easily during the wiring removal process, increasing the risk of short circuit of the power module to be tested, and the short circuit may cause the power module to be burned;

[0044] 3. In the double pulse test process, it is inevitable that the power supply of the power module to be tested is forgotten to be turned off. The power supply of the power module to be tested includes a high-voltage power supply and a low-voltage power supply. If the high-voltage power supply is forgotten to be turned off, the tester may be in danger of electric shock after accidentally touching it, causing serious damage to the body or even death. If the low-voltage power supply is forgotten to be turned off, the power module to be tested may be short-circuited during the wiring operation, and even the power module to be tested may be burned.

[0045] In order to simplify manual operation and improve the efficiency of double pulse testing, the embodiment of the utility model discloses a double pulse testing auxiliary device. The technical scheme in the embodiment of the utility model will be clearly and completely described below in combination with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0046] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to be limitations on the present invention. As used in the specification of the present invention and the appended claims, the singular expressions "one", "a kind", "said", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear contrary indication in the context. It should also be understood that in the embodiments of the present invention, "one or more" refers to one, two or more; "and / or" describes the association relationship of associated objects, indicating that three relationships may exist; for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0047] The double pulse test auxiliary device disclosed in the embodiment of the utility model is as follows Figure 1 As shown, it includes: input and output devices, a main control board, a controllable switch, an output selection circuit and n (n ≥ 1, Figure 1 Only n=3 is used as an example) input selection circuits;

[0048] The main control board is the core control unit of the double pulse test auxiliary device, which is used to realize data processing and instruction forwarding, etc.

[0049] The input and output devices are connected to the main control board to realize human-computer interaction;

[0050] The input end of the controllable switch is connected to a low-voltage power supply (the low-voltage power supply is, for example, a battery or a digital power supply, etc. The low-voltage power supply can be an external power supply or a power supply module provided by the double-pulse test auxiliary device. Figure 1 The low-voltage power supply is only taken as an external digital power supply as an example), the output end of the controllable switch is connected to the power module to be tested, and the control end of the controllable switch is connected to the main control board; the controllable switch is used to connect or disconnect the low-voltage power supply of the power module to be tested under the control of the main control board;

[0051] The power module to be tested includes m power switch devices and a driving circuit respectively arranged corresponding to each power switch device, where m≥2;

[0052] The output selection circuit has a control terminal, a single input terminal and m( Figure 1 The output selection circuit is used to select one of the m output terminals and connect it to the input terminal under the control of the main control board, and output a double-pulse drive signal for controlling the on and off of one power switch device, and the double-pulse drive signal is amplified by the drive circuit and output to the power switch device;

[0053] The input selection circuit has a control end, m-way input ends and a single-way output end, wherein the m-way input ends are connected to the m power switch devices one-to-one, the output end is connected to the measuring instrument, and the control end is connected to the main control board; the input selection circuit is used to select one of the m-way input ends to be connected to the output end under the control of the main control board, and collect and output the signal to be measured of one power switch device;

[0054] When n≥2, different input selection circuits collect different signals to be tested, and the n signals to be tested of the same power switching device can be measured individually or in combination; still taking the aforementioned three-phase inverter as an example, the input selection circuit 1 is used to collect the Vgs signals of the six SiC-MOSFETs one by one, the input selection circuit 2 is used to collect the Vds signals of the six SiC-MOSFETs one by one, and the input selection circuit 3 is used to collect the Ids signals of the six SiC-MOSFETs one by one.

[0055] Below Figure 1 The working principle of the scheme shown is described in detail:

[0056] After the double pulse test auxiliary device is powered on, the tester selects which power switch device in the power module to be tested and which one or several test signals of the power switch device to be collected through the input and output devices; then, the main control board determines which output end of the output selection circuit is to be connected to the input end, and which input end of the corresponding input selection circuit is to be connected to the output end according to the user's selection, and completes the channel selection accordingly. Still taking the aforementioned three-phase inverter as an example, the tester can first select the Vgs signal of the U-phase upper bridge arm SiC-MOSFET to be tested through the input and output devices, and the main control board controls the output selection circuit to connect the output end connected to the driving circuit of the U-phase upper bridge arm SiC-MOSFET to the input end, and controls the input selection circuit 1 to connect the input end connected to the U-phase upper bridge arm SiC-MOSFET to the output end.

[0057] After completing the channel selection, the main control board controls the controllable switch to close, so as to realize the low-voltage power supply to the power module to be tested, and the high-voltage power supply to the power module to be tested is manually connected by the tester; the power module to be tested starts to work after the high-voltage power supply and the low-voltage power supply are connected, and the double pulse test is started at this time, including: the signal generator sends a double pulse drive signal to the drive circuit of the current power switch device to be tested through the output selection circuit to control the on and off of the current power switch device to be tested, and at the same time, the corresponding input selection circuit collects the test signal of the current power switch device to be tested and outputs it to the measuring instrument.

[0058] When it is necessary to collect other test signals of the current power switching device to be tested, the tester makes corresponding selections through the input and output devices, and the double pulse test auxiliary device can automatically complete the collection of the other test signals; the measuring instrument analyzes these test signals to obtain the electrical characteristics of the current power switching device to be tested, thereby completing the double pulse test of the current power switching device to be tested.

[0059] When the next power switch device needs to be tested with a double pulse, the high-voltage power supply and low-voltage power supply of the current power module to be tested are disconnected first. After the tester manually connects the high-voltage power supply (each time a different power switch device is switched, the access point of the low-voltage power supply does not need to be moved, but the access point of the high-voltage power supply has a change in position), the tester can make corresponding selections through the input and output devices again. After the double pulse test of all power switch devices is completed, the double pulse test auxiliary device is turned off, including closing the channel and cutting off the power supply to the entire double pulse test auxiliary device.

[0060] In summary, the main control board in the embodiment of the utility model automatically starts testing after the power module to be tested is powered on according to the test requirements input by the tester, including: controlling the output selection circuit to output a double-pulse drive signal for controlling the on and off of a power switch device, and controlling the input selection circuit to only collect and output the test signal of the power switch device, thereby assisting the measuring instrument to complete the double-pulse test of the power switch device; when the next power switch device needs to be tested, the tester only needs to input a new test requirement, and the tester does not need to perform disconnection and wiring operations between the measuring instrument and different power switch devices, saving test time, improving test efficiency, and avoiding the problem of test point falling off that may be caused by frequent disconnection. Moreover, the on and off of the low-voltage power supply of the power module to be tested is automatically controlled by the main control board, and the tester does not need to manually turn it on and off, thereby avoiding the short circuit of the power module to be tested that may be caused during the disconnection and wiring operation when the tester forgets to turn off the low-voltage power supply.

[0061] Optionally, in any of the embodiments disclosed above, the input-output device may be, for example, a touch screen or a combination of a keyboard and a display, and the touch screen may be, for example, an LCD touch screen.

[0062] Optionally, based on any of the embodiments disclosed above, see Figure 2 The output selection circuit also includes an m+1th output terminal; the m+1th output terminal is connected to the main control board, which is used to feed back the dual-pulse drive signal to the main control board, so that the main control board can monitor whether the dual-pulse signal sent to the power switch device is abnormal.

[0063] Optionally, based on any of the embodiments disclosed above, still refer to Figure 2, the double pulse test auxiliary device also includes: a spare positive and negative power supply module, which is used to replace the positive and negative power supply modules of the power switch device itself and connect to the power module to be tested when the gate voltage of the power switch device to be tested is abnormal, so as to ensure that the drive circuit outputs a standard gate turn-on voltage or gate turn-off voltage to the power switch device. Specifically, the signal to be tested includes the gate voltage of the power switch device, that is, the Vgs signal; when the positive and negative power supply modules of the power switch device itself have the problem of inaccurate nominal, it is impossible to determine whether the abnormal Vgs signal is due to the problem of the drive circuit or the positive and negative power supply module itself. Therefore, when the Vgs signal is found to be abnormal, the positive and negative power supply modules of the power switch device itself can be removed and connected to the standard positive and negative power supply modules provided by the double pulse test auxiliary device.

[0064] When the input-output device adopts a touch screen and the double-pulse test auxiliary device includes a backup positive and negative power supply module, the main visual axis side view of the double-pulse test auxiliary device is as follows: Figure 3 As shown: the housing 4 of the double pulse test auxiliary device is surrounded by a side plate, a bottom plate 1 and an upper cover plate 8, and the side plate is provided with a main power switch 5 for powering the entire double pulse test auxiliary device, an interface power module 11 of a standby positive and negative power module, an AC power interface 2 (the power supply for the entire double pulse test auxiliary device is taken from the AC power interface 2, such as a mains interface), a DC power interface 3 (used to access the low-voltage power supply of the power module to be tested) and an input / output port 9 (including the output end of the output selection circuit and the input end of m input selection circuits), a touch screen 6 is installed on the upper cover plate 8, and a handle 10 is installed on the side plate, so that the double pulse test auxiliary device is easy to carry. It is recommended to select insulating materials for the housing 4, so as to avoid the risk of electric shock caused by the tester accidentally touching the housing 4 after the high voltage electricity falls on the power module to be tested. The interface power module 9 of the multiple-choice switch circuit is provided with a ring 7, which is convenient for the connection of the differential probe, the ordinary probe and the Rogowski coil with the double pulse test auxiliary device.

[0065] Optionally, based on any of the above-disclosed embodiments, in order to avoid the risk of module burning during the test process, the dual-pulse test auxiliary device also includes: an alarm connected to the main control board and a temperature sensor for collecting temperature information of the power module to be tested, and the output end of the temperature sensor is connected to the main control board. In addition, when the power module to be tested has its own temperature sensor, there is no need to introduce an additional temperature sensor, and the output end of the temperature sensor of the power module to be tested can be directly connected to the main control board. When a sudden rise in the temperature of the power module to be tested is detected during the measurement process, the main control board forces the entire dual-pulse test auxiliary device to be shut down and alarms to avoid the risk of burning the power module to be tested. The alarm form is, for example, a flash alarm and a buzzer alarm, etc., but is not limited.

[0066] In addition, considering that the tester may forget to disconnect the high-voltage power supply when replacing the power module to be tested, the tester may be in danger of electric shock after accidentally touching it. When the tester replaces the power module to be tested, the position and load-bearing capacity of the double-pulse test auxiliary device will usually change. Therefore, it is possible to determine whether the above situation occurs based on the position and / or load-bearing changes of the double-pulse test auxiliary device. If so, the double-pulse test auxiliary device is controlled to perform a power-off operation and an alarm. In this regard, based on any of the above-disclosed embodiments, still refer to Figure 2 The double pulse test auxiliary device may also include: an alarm connected to the main control board, and a position sensor and / or a mass sensor connected to the main control board; the position sensor is generally mounted on the bottom plate of the double pulse test auxiliary device, and is used to measure the position of the double pulse test auxiliary device; the mass sensor is used to measure the load-bearing capacity of the double pulse test auxiliary device; when the position sensor and / or the mass sensor generates abnormal data, the double pulse test auxiliary device is controlled to perform a power-off operation and alarm.

[0067] Optionally, based on any of the above disclosed embodiments, the double pulse test auxiliary device usually performs a power-on self-test after being powered on, and enters a normal working state only after the self-test passes. When the power module is a battery, the power-on self-test includes, for example: detecting whether the power of the power module is sufficient, and alarming if the power is insufficient.

[0068] Optionally, based on any of the embodiments disclosed above, if the main control board detects that the double pulse test auxiliary device is forgotten to be turned off after the test is completed, the power supply of the double pulse test auxiliary device is automatically turned off, thereby reducing energy waste.

[0069] Optionally, based on any of the above disclosed embodiments, a switch circuit is provided between each output terminal and input terminal of the output selection circuit, see Figure 4 , the switch circuit includes: a current limiting resistor R1, a diode D1, a switch tube Q1 and a normally open relay K1;

[0070] Among them, the cathode of the diode D1 is connected to the power supply VCC, and the anode of the diode D1 is connected to the input electrode of the switch tube Q1; the output electrode of the switch tube Q1 is grounded GND, and the control electrode of the switch tube is connected to the main control board through the current limiting resistor R1; the coil of the normally open relay K1 is connected in parallel with the diode D1, and the normally open contact of the normally open relay K1 is connected to the main circuit, that is, connected between one output end and one input end of the output selection circuit.

[0071] Figure 4The working principle of the circuit shown is as follows: when a channel is selected to be turned on, a high level is sent to the control electrode of the switch tube Q1 through the main control board, so that the switch tube Q1 is turned on. After the switch tube Q1 is turned on, a path is formed between VCC and GND, and the coil between the relay pins 1 and 4 is energized, so that the normally open contact of the relay is turned on, that is, the normally open contact of the relay is switched from pins 2 and 3 to pins 2 and 5, and the channel is turned on. Diode D1 is used to limit the current direction.

[0072] The switch circuit is also provided between each input terminal and output terminal of the input selection circuit, the only difference being that the normally open contact of the normally open relay K1 is connected between one input terminal and output terminal of the input selection circuit.

[0073] Optionally, the switch tube Q1 can be a MOSFET or an NPN switch tube. Figure 4 Only the NPN switch tube is used as an example. When the switch tube Q1 is a MOSFET, the input pole of the switch tube Q1 is the drain of the MOSFET, the output pole of the switch tube Q1 is the source of the MOSFET, and the control pole of the switch tube Q1 is the gate of the MOSFET. When the switch tube Q1 is an NPN transistor, the input pole of the switch tube Q1 is the collector of the NPN transistor, the output pole of the switch tube Q1 is the emitter of the NPN transistor, and the control pole of the switch tube Q1 is the base of the NPN transistor. For cost considerations, the embodiment of the utility model recommends that the switch tube Q1 adopt an NPN switch tube.

[0074] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other and will not be repeated here.

[0075] The terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish between similar different objects, and are not necessarily used to describe a specific order or sequence. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of further restrictions, the elements defined by the sentence "comprising one" do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0076] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present invention. Therefore, the embodiments of the present invention will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A double pulse test auxiliary device, characterized in that: include: Input and output devices, main control board, controllable switch, output selection circuit and n input selection circuits, n≥1; Wherein, the input and output devices are connected to the main control board to realize human-computer interaction; The input end of the controllable switch is connected to a low-voltage power supply, the output end of the controllable switch is connected to a power module to be tested, and the control end of the controllable switch is connected to the main control board; the power module to be tested includes m power switch devices and a driving circuit respectively arranged for each power switch device, m≥2; The output selection circuit has a control end, a single input end and m output ends, the input end of which is connected to a signal generator, the m output ends of which are connected to the m driving circuits one-to-one, and the control end of which is connected to the main control board; the output selection circuit is used to select one of the m output ends to be connected to the input end under the control of the main control board, and output a double-pulse driving signal for controlling the on and off of one power switch device; The input selection circuit has a control end, m-way input ends and a single-way output end, wherein the m-way input ends are connected one-to-one to the m power switch devices, the output end is connected to the measuring instrument, and the control end is connected to the main control board; the input selection circuit is used to select one of the m-way input ends to be connected to the output end under the control of the main control board, collect and output the signal to be tested of one power switch device; when n≥2, different input selection circuits are used to collect different signals to be tested.

2. The double pulse test auxiliary device according to claim 1, characterized in that: The output selection circuit also includes an (m+1)th output terminal; The m+1th output end is connected to the main control board and is used to feed back the double-pulse driving signal to the main control board.

3. The double pulse test auxiliary device according to claim 1 or 2, characterized in that: The signal to be measured includes a gate voltage of a power switch device; The double pulse test auxiliary device also includes: a spare positive and negative power supply module; The standby positive and negative power supply modules are used to replace the positive and negative power supply modules of the power switch device itself when the gate voltage of the power switch device is abnormal.

4. The double pulse test auxiliary device according to claim 1 or 2, characterized in that: The shell of the double pulse test auxiliary device is made of insulating material.

5. The double pulse test auxiliary device according to claim 1 or 2, characterized in that: The double pulse test auxiliary device also includes: an alarm connected to the main control board and a temperature sensor for collecting temperature information of the power module to be tested, and the output end of the temperature sensor is connected to the main control board.

6. The double pulse test auxiliary device according to claim 1 or 2, characterized in that: The double pulse test auxiliary device further comprises: an alarm connected to the main control board, and a position sensor and / or a quality sensor connected to the main control board; The position sensor is used to measure the position of the double-pulse test auxiliary device; the mass sensor is used to measure the load-bearing capacity of the double-pulse test auxiliary device.

7. The double pulse test auxiliary device according to claim 1 or 2, characterized in that: A switch circuit is provided between each output terminal and input terminal of the output selection circuit; The switch circuit includes: a current limiting resistor R1, a diode D1, a switch tube Q1 and a normally open relay K1; Among them, the cathode of the diode D1 is connected to the power supply, and the anode of the diode D1 is connected to the input electrode of the switch tube Q1; the output electrode of the switch tube Q1 is grounded, and the control electrode of the switch tube is connected to the main control board through the current limiting resistor R1; the coil of the normally open relay K1 is connected in parallel with the diode D1; and the normally open contact of the normally open relay K1 is connected to the main circuit.

8. The double pulse test auxiliary device according to claim 7, characterized in that: The switch circuit is arranged between each input terminal and output terminal of the input selection circuit.

9. The double pulse test auxiliary device according to claim 7, characterized in that: The switch tube Q1 is an NPN transistor.

10. The double pulse test auxiliary device according to claim 1 or 2, characterized in that: The input-output device is a touch screen.

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