Double-pulse test circuit

Abstract

The invention relates to the technical field of power module test circuits, in particular to a double-pulse test circuit. The device comprises a test unit, a module unit, a first switch unit and a second switch unit. The module unit comprises an IGBT tube Q1, an IGBT tube Q2, a diode FRD1, a diode FRD2 and an inductor Ls. And the inductor Ls is connected with different IGBTs through the switching of the second switch unit. The first switch unit comprises seven ganged switches, and the multiple ganged switches are respectively connected with three poles of a tested IGBT tube and positive and negative poles of a tested diode FRD in a switchable manner, and directly switch the required tested IGBT tube and the tested diode FRD. Therefore, the position of the interface and the DSP drive do not need to be changed, and repeated wiring is avoided. Only one path of driving IC is needed, multi-path signal interference does not exist, the position of an interface does not need to be changed, and signal acquisition errors caused by manual operation are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of power module test circuits, and in particular to a double pulse test circuit. Background Art

[0002] IGBT is an abbreviation for insulated gate bipolar transistor. It has the characteristics of low on-state voltage drop and high input impedance. It is often used as a switching device in the field of electronic circuits. It controls the circuit by applying voltage to the gate. As a key component in the field of power electronics, the performance test of IGBT is crucial to ensure the reliability and stability of the entire power electronics system. At present, the double pulse test method is usually used to perform dynamic performance tests on IGBT modules to evaluate their switching characteristics under actual working conditions. The double pulse signal makes the IGBT alternate between the on and off states, which makes it easier to simulate the voltage and current changes of the IGBT during the application process.

[0003] In the past, a double pulse test method was usually used to test IGBT devices. The common double pulse test method mostly tests one IGBT. When it is applied to test IGBT modules with three-phase or half-bridge circuit structures, since different test modules and test circuits need to be tested, the test circuit needs to be frequently replaced and the device position needs to be frequently changed, resulting in low test efficiency. Summary of the invention

[0004] In view of this, the present invention provides a double pulse test circuit to solve the above technical problem.

[0005] A double pulse test circuit, comprising a test unit, a module unit, a first switch unit electrically connected to the test unit and the module unit, and a second switch unit electrically connected to the module unit, wherein the module unit comprises an IGBT tube Q1, an IGBT tube Q2, a diode FRD1, a diode FRD2, a drive power supply VCC, a ground terminal GND, and an inductor Ls, wherein one end of the inductor Ls is connected to the circuit midpoint between the emitter of the IGBT tube Q1 and the collector of the IGBT tube Q2, and the other end of the inductor Ls is connected to the second switch unit, and the second switch unit The first switch unit includes a double switch, a contact 1 of the second switch unit is connected to one end of the inductor Ls, a contact 2 of the second switch unit is connected between a driving power supply VCC and the collector of the IGBT tube Q1, a contact 3 of the second switch unit is connected between a ground terminal GND and the emitter of the IGBT tube Q2, and the inductor Ls is connected to different IGBT tubes by switching the second switch unit. The first switch unit includes seven double switches, and the seven double switches are respectively connected to electrodes of multiple IGBT tubes in the module unit. By opening different double switches, an IGBT tube is connected for testing.

[0006] Further, the test unit includes a DSP signal board, a driver IC connected to the DSP signal board, a C sampling point connected to the driver IC, a G sampling point connected to the driver IC, an E sampling point connected to the driver IC, an F sampling point, and an FE sampling point. The driver IC has three output terminals, namely, a Vc output terminal, a Vg output terminal, and a Ve output terminal. One end of the C sampling point, the G sampling point, and the E sampling point is respectively connected to the Vc output terminal, the Vg output terminal, and the Ve output terminal, and the other end is connected to the collector, gate, and emitter of the IGBT under test in the module unit through the first switch unit. One end of the F sampling point and the FE sampling point is connected to the positive and negative electrodes of the diode FRD under test in the module unit through the first switch unit.

[0007] Furthermore, the module unit also includes a capacitor C, two ends of the capacitor C are respectively connected to the ground terminal GND and the driving power supply VCC, and the capacitor C is connected to the circuit as a bus capacitor.

[0008] Further, the collector of the IGBT tube Q1 is connected to the driving power supply VCC, the emitter of the IGBT tube Q1 is connected to the collector of the IGBT tube Q2, the emitter of the IGBT tube Q2 is connected to the ground terminal GND, the cathode of the diode FRD1 is connected to the collector of the IGBT tube Q1, the anode of the diode FRD1 is connected to the emitter of the IGBT tube Q1, the cathode of the diode FRD2 is connected to the collector of the IGBT tube Q2, and the anode of the diode FRD2 is connected to the emitter of the IGBT tube Q2, so that the IGBT tube Q1 and the diode FRD1 serve as an upper bridge of the circuit, and the IGBT tube Q2 and the diode FRD2 serve as a lower bridge of the circuit.

[0009] Further, the contact 1 of the first switch unit is connected to the test unit, the contact 8 of the first switch unit is connected to the collector of the IGBT tube Q2, the contact 9 of the first switch unit is connected to the collector of the IGBT tube Q1, the contact 2 of the first switch unit is connected to the test unit, the contact 10 of the first switch unit is connected to the gate of the IGBT tube Q2, the contact 11 of the first switch unit is connected to the gate of the IGBT tube Q1, the contact 3 of the first switch unit is connected to the test unit, the contact 12 of the first switch unit is connected to the emitter of the IGBT tube Q2, the contact 13 of the first switch unit is connected to the emitter of the IGBT tube Q1, the contact 4 of the first switch unit is connected to the sampling point F, and the contact 5 of the first switch unit is connected to the sampling point F. Point 14 is connected to the anode of diode FRD1, contact 15 of the first switch unit is connected to the anode of diode FRD2, contact 5 of the first switch unit is connected to sampling point FE, contact 16 of the first switch unit is connected to the cathode of diode FRD1, contact 17 of the first switch unit is connected to the cathode of diode FRD2, contact 6 of the first switch unit is connected to the emitter of IGBT tube Q2, contact 18 of the first switch unit is vacant, contact 19 of the first switch unit is connected to the gate of IGBT tube Q2, contact 7 of the first switch unit is connected to the emitter of IGBT tube Q1, contact 20 of the first switch unit is connected to the gate of IGBT tube Q1, and contact 21 of the first switch unit is vacant.

[0010] Furthermore, the double pulse test circuit also includes a three-phase bridge module unit, a third switch unit connected to the first switch unit and the three-phase bridge module unit, and a fourth switch unit connected to the three-phase bridge module unit, and the three-phase bridge module unit includes IGBT tube Q1, IGBT tube Q2, IGBT tube Q3, IGBT tube Q4, IGBT tube Q5, IGBT tube Q6, diode FRD1, diode FRD2, diode FRD3, diode FRD4, diode FRD5, and diode FRD6.

[0011] Further, the fourth switch unit includes a triple switch, the contact 1 of the fourth switch unit is connected to one end of the inductor Ls, the contact 2 of the fourth switch unit is connected to the middle point of the IGBT tube Q5 and the IGBT tube Q6, the contact 3 of the fourth switch unit is connected to the middle point of the IGBT tube Q3 and the IGBT tube Q4, the contact 4 of the fourth switch unit is connected to the middle point of the IGBT tube Q1 and the IGBT tube Q2, and the inductor Ls is connected to the IGBT tube of the upper bridge or the lower bridge by switching the second switch unit, and the inductor Ls is connected to one of the IGBT tubes in the upper bridge or the lower bridge by switching the fourth switch unit.

[0012] Compared with the prior art, the double pulse test circuit provided by the present invention realizes the switching of the IGBT under test by adding a first switch unit between the test unit and the module unit. Specifically, the first switch unit includes seven double switches, and the seven double switches are respectively connected to the electrodes of multiple IGBT tubes in the module unit. The collector, gate, emitter of the IGBT tube under test and the positive and negative electrodes of the diode FRD under test can be switched through multiple double switches, so that the desired IGBT tube under test and the diode FRD under test can be directly switched. In this way, the detection of different IGBT tubes and diodes can be realized by directly switching the switch. The position of the interface and the DSP drive do not need to be changed, avoiding repeated wiring. Only one drive IC is required to avoid multi-channel signal interference, and the interface position does not need to be changed, avoiding manual operation to cause signal acquisition errors. In addition, there will be two double switches in the first switch unit to short-circuit the IGBT that is not detected, so that the IGBT that is not detected is short-circuited to protect it, ensuring that it will not be mis-conducted and avoiding parasitic conduction. At the same time, the short-circuit protection of which IGBT can also be quickly switched by the double switch. For the three-bridge test structure, fast switching is achieved by adding a third switch unit and a fourth switch unit. The third switch unit includes twelve triple switches (L1~L12). The upper bridge or the lower bridge is switched through the multiple double switches of the first switch unit, and one IGBT tube in the upper bridge or the lower bridge is connected through the multiple triple switches of the third switch unit to avoid repeated wiring. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A principle block diagram of a double pulse test circuit provided by the present invention.

[0014] Figure 2 for Figure 1 Circuit diagram of the double pulse test circuit.

[0015] Figure 3 for Figure 1 Circuit diagram of the double pulse test circuit when detecting a three-phase circuit. DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention are further described in detail below. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the protection scope of the present invention.

[0017] like Figure 1 As shown, it is a schematic diagram of the structure of the double pulse test circuit provided by the present invention. The double pulse test circuit includes a test unit 100, a module unit 200, a first switch unit 300 electrically connected to the test unit 100 and the module unit 200, and a second switch unit 400 electrically connected to the module unit 200. It can be imagined that the double pulse test circuit also includes some other functional modules, such as a control module, a data acquisition device, and a power supply module, etc., which are well known to those skilled in the art and will not be repeated here.

[0018] The test unit 100 includes a DSP signal board, a driver IC connected to the DSP signal board, a C sampling point connected to the driver IC, a G sampling point connected to the driver IC, an E sampling point connected to the driver IC, an F sampling point, and an FE sampling point.

[0019] DSP signal is a signal in digital signal processing, which refers to a signal that has been digitally processed. The DSP signal board is a hardware platform specifically used for processing digital signals, converting analog signals into digital signals, and is mainly used to generate digital signals so that the driver IC can drive the module unit 200.

[0020] The driver IC has three output terminals, namely, a Vc output terminal, a Vg output terminal, and a Ve output terminal. The driver IC is used to control the digital signal generated by the DSP signal board, and convert the digital signal into the driving signal required by the module unit 200 so that it can work normally. One end of the C sampling point, the G sampling point, and the E sampling point is connected to the Vc output terminal, the Vg output terminal, and the Ve output terminal respectively, and the other end is connected to the collector, the gate, and the emitter of the IGBT under test in the module unit 200 through the first switch unit 300, so as to detect the voltage of the corresponding electrode of the IGBT. One end of the F sampling point and the FE sampling point is connected to the positive electrode and the negative electrode of the FRD under test in the module unit 200 through the first switch unit 300, so as to detect the voltage of the positive electrode and the negative electrode of the corresponding diode FRD.

[0021] The module unit 200 includes an IGBT tube Q1, an IGBT tube Q2, a diode FRD1, a diode FRD2, a driving power source VCC, a capacitor C, a ground terminal GND, and an inductor Ls.

[0022] The collector of the IGBT tube Q1 is connected to the driving power supply VCC, the emitter of the IGBT tube Q1 is connected to the collector of the IGBT tube Q2, and the gate of the IGBT tube Q1 is connected to the first switch unit 300. The emitter of the IGBT tube Q2 is connected to the ground terminal GND, and the gate of the IGBT tube Q2 is connected to the first switch unit 300.

[0023] The cathode of the diode FRD1 is connected to the collector of the IGBT tube Q1, and the anode of the diode FRD1 is connected to the emitter of the IGBT tube Q1. The cathode of the diode FRD2 is connected to the collector of the IGBT tube Q2, and the anode of the diode FRD2 is connected to the emitter of the IGBT tube Q2, so that the IGBT tube Q1 and the diode FRD1 form an upper bridge of the circuit, and the IGBT tube Q2 and the diode FRD2 form a lower bridge of the circuit, so that the IGBT tube Q1, the IGBT tube Q2, the diode FRD1, and the diode FRD2 form a half-bridge circuit.

[0024] The two ends of the capacitor C are connected to the ground terminal GND and the driving power supply VCC respectively. The capacitor C is connected to the circuit as a bus capacitor. The bus capacitor can smooth the bus voltage, reduce voltage fluctuations and noise, and thus improve the stability and reliability of the motor controller.

[0025] The inductor Ls is connected to the circuit as an inductive load, one end of the inductor Ls is connected to the circuit midpoint of the emitter of the IGBT tube Q1 and the collector of the IGBT tube Q2 , and the other end of the inductor Ls is connected to the second switch unit 400 .

[0026] The second switch unit 400 includes a double switch, wherein the contact 1 of the second switch unit 400 is connected to one end of the inductor Ls, and the contact 2 of the second switch unit 400 is connected between the driving power supply VCC and the collector of the IGBT tube Q1. The contact 3 of the second switch unit 400 is connected between the ground terminal GND and the emitter of the IGBT tube Q2. The inductor Ls is connected to different IGBT tubes by switching the second switch unit 400. When the IGBT tube Q1 is detected, the contact 1 of the second switch unit 400 is connected to the contact 3, and when the IGBT tube Q2 is detected, the contact 1 of the second switch unit 400 is connected to the contact 2.

[0027] The first switch unit 300 includes seven double switches (K1~K7), which are respectively connected to the electrodes of multiple IGBT tubes in the module unit 200. By opening different double switches, an IGBT tube can be selectively connected for testing. Specifically, the contact 1 of the first switch unit 300 is connected to the Vc output terminal of the driver IC and the C sampling point, the contact 8 of the first switch unit 300 is connected to the collector of the IGBT tube Q2, and the contact 9 of the first switch unit 300 is connected to the collector of the IGBT tube Q1.

[0028] The contact 2 of the first switch unit 300 is connected to the Vg output terminal of the driver IC and the sampling point G, the contact 10 of the first switch unit 300 is connected to the gate of the IGBT tube Q2, and the contact 11 of the first switch unit 300 is connected to the gate of the IGBT tube Q1.

[0029] The contact 3 of the first switch unit 300 is connected to the Ve output terminal of the driver IC and the sampling point E, the contact 12 of the first switch unit 300 is connected to the emitter of the IGBT tube Q2, and the contact 13 of the first switch unit 300 is connected to the emitter of the IGBT tube Q1.

[0030] The contact 4 of the first switch unit 300 is connected to the sampling point F, the contact 14 of the first switch unit 300 is connected to the anode of the diode FRD1, and the contact 15 of the first switch unit 300 is connected to the anode of the diode FRD2.

[0031] The contact 5 of the first switch unit 300 is connected to the sampling point FE, the contact 16 of the first switch unit 300 is connected to the cathode of the diode FRD1, and the contact 17 of the first switch unit 300 is connected to the cathode of the diode FRD2.

[0032] The contact 6 of the first switch unit 300 is connected to the emitter of the IGBT tube Q2, the contact 18 of the first switch unit 300 is vacant, and the contact 19 of the first switch unit 300 is connected to the gate of the IGBT tube Q2.

[0033] The contact 7 of the first switch unit 300 is connected to the emitter of the IGBT tube Q1 , the contact 20 of the first switch unit 300 is connected to the gate of the IGBT tube Q1 , and the contact 21 of the first switch unit 300 is vacant.

[0034] The collector, gate, emitter of the IGBT tube under test and the positive and negative electrodes of the diode FRD under test can be switched respectively through multiple double switches, so that the desired IGBT tube under test and the diode FRD under test can be directly switched. The contact 6 and the contact 7 of the first switch unit 300 are used to short-circuit the other IGBT tube during the test. Specifically, taking the test IGBT tube Q1 and the diode FRD2 as an example, the switch setting is the same as Figure 2 The positions shown are the same, contact 1 in the first switch unit 300 is connected to contact 9, contact 2 in the first switch unit 300 is connected to contact 11, contact 3 in the first switch unit 300 is connected to contact 13, contact 4 in the first switch unit 300 is connected to contact 15, contact 5 in the first switch unit 300 is connected to contact 17, contact 6 in the first switch unit 300 is connected to contact 19, contact 7 in the first switch unit 300 is connected to contact 21, and contact 1 in the second switch unit 400 is connected to contact 3. At this time, sampling points C, G, and E are respectively connected to the collector, gate, and emitter of the IGBT tube Q1, and sampling points F and FE are respectively connected to the positive and negative electrodes of FRD2. The gate and emitter of the IGBT tube Q2 are short-circuited by connecting contact 6 and contact 19 in the first switch unit 300, so that the IGBT tube Q2 is normally closed to ensure that it will not be mis-conducted. The voltage of each point is obtained through sampling points C, G, E, F, and FE, and the current of IGBT tube Q1 and diode FRD2 is obtained by an external current sensor. After the driving power supply VCC voltage is given, the driving signal is given through the DSP signal board, and the driving IC drives the IGBT tube Q1 to open and close, and the voltage and current waveforms of IGBT tube Q1 and diode FRD2 can be obtained at the same time for analysis. It can be imagined that the voltage and current waveforms are collected by a data collector.

[0035] When testing the IGBT tube Q2 and the diode FRD1, it is only necessary to connect the contact 1 in the first switch unit 300 with the contact 8, the contact 2 in the first switch unit 300 with the contact 10, the contact 3 in the first switch unit 300 with the contact 12, the contact 4 in the first switch unit 300 with the contact 14, the contact 5 in the first switch unit 300 with the contact 16, the contact 6 in the first switch unit 300 with the contact 18, the contact 7 in the first switch unit 300 with the contact 20, and the contact 1 in the second switch unit 400 with the contact 2. At this time, the sampling points C, G, and E are respectively connected to the collector, gate, and emitter of the IGBT tube Q2, and the sampling points F and FE are respectively connected to the positive and negative electrodes of FRD1, so that different IGBT tubes and diodes can be tested by directly switching the switches. The position of the interface and the DSP driver do not need to be changed. After the driving power supply VCC voltage is given, the driving signal is given through the DSP signal board. The driver IC drives the IGBT tube Q2 to open and close, and the voltage and current waveforms of the IGBT tube Q2 and the diode FRD1 can be obtained for analysis. During the test, the DSP signal does not need to be changed, the control method is simple, there is no error in the output of the bridge arm signal, and only one driver IC is required, there is no multi-channel signal interference, the interface position does not need to be changed, and manual operation is avoided to avoid signal acquisition errors. The electronic components that are not tested are short-circuited to avoid parasitic conduction.

[0036] Second embodiment.

[0037] For testing other bridge circuits such as three-phase bridge test structure, detection can be achieved by adding switch groups, such as Figure 3 As shown, it is a circuit schematic diagram of the double pulse test of the three-phase circuit provided by the present invention. The double pulse test circuit includes a test unit 100, a three-phase bridge module unit 500, a first switch unit 300 electrically connected to the test unit 100 and the three-phase bridge module unit 500, a second switch unit 400 electrically connected to the three-phase bridge module unit 500, a third switch unit 600 connected to the first switch unit 300 and the three-phase bridge module unit 500, and a fourth switch unit 700 connected to the three-phase bridge module unit 500.

[0038] The difference between the three-phase bridge module unit 500 and the module unit 200 is that it changes from one phase to three phases, so four IGBT tubes and four diodes FRD are added to form a three-phase circuit. The three-phase bridge module unit 500 includes IGBT tube Q1, IGBT tube Q2, IGBT tube Q3, IGBT tube Q4, IGBT tube Q5, IGBT tube Q6, diode FRD1, diode FRD2, diode FRD3, diode FRD4, diode FRD5, and diode FRD6. The composition of the three-phase bridge module unit 500 should be the existing technology, which will not be repeated here.

[0039] The fourth switch unit 700 includes a triple switch, wherein the contact 1 of the fourth switch unit 700 is connected to one end of the inductor Ls, the contact 2 of the fourth switch unit 700 is connected to the middle point of the IGBT tube Q5 and the IGBT tube Q6, the contact 3 of the fourth switch unit 700 is connected to the middle point of the IGBT tube Q3 and the IGBT tube Q4, and the contact 4 of the fourth switch unit 700 is connected to the middle point of the IGBT tube Q1 and the IGBT tube Q2. The inductor Ls is connected to the IGBT tube of the upper bridge or the lower bridge by switching of the second switch unit 400. The inductor Ls is connected to an IGBT tube of the upper bridge or the lower bridge by switching of the fourth switch unit 700, thereby realizing the load connection of a single IGBT tube in the three-phase circuit.

[0040] The third switch unit 600 includes twelve triple switches (L1~L12). Specifically, the contact 1 of the third switch unit 600 is connected to the contact 9 of the first switch unit 300 and the contact 16 of the first switch unit 300, the contact 13 of the third switch unit 600 is connected to the collector of the IGBT tube Q5, the contact 14 of the third switch unit 600 is connected to the collector of the IGBT tube Q3, and the contact 15 of the third switch unit 600 is connected to the collector of the IGBT tube Q1.

[0041] The contact 2 of the third switch unit 600 is connected to the contact 11 of the first switch unit 300 and the contact 20 of the first switch unit 300, the contact 16 of the third switch unit 600 is connected to the gate of the IGBT tube Q5, the contact 17 of the third switch unit 600 is connected to the gate of the IGBT tube Q3, and the contact 18 of the third switch unit 600 is connected to the gate of the IGBT tube Q1.

[0042] The contact 3 of the third switch unit 600 is connected to the contact 13 of the first switch unit 300, the contact 14 of the first switch unit 300 and the contact 7 of the first switch unit 300, the contact 19 of the third switch unit 600 is connected to the emitter of the IGBT tube Q5, the contact 20 of the third switch unit 600 is connected to the emitter of the IGBT tube Q3, and the contact 21 of the third switch unit 600 is connected to the emitter of the IGBT tube Q1.

[0043] The contact 4 of the third switch unit 600 is connected to the emitter of the IGBT tube Q1, the contact 22 of the third switch unit 600 is connected to the gate of the IGBT tube Q1, the contact 23 of the third switch unit 600 is connected to the gate of the IGBT tube Q1, and the contact 24 of the third switch unit 600 is vacant.

[0044] The contact 5 of the third switch unit 600 is connected to the emitter of the IGBT tube Q3, the contact 25 of the third switch unit 600 is connected to the gate of the IGBT tube Q3, the contact 26 of the third switch unit 600 is vacant, and the contact 27 of the third switch unit 600 is connected to the gate of the IGBT tube Q3.

[0045] The contact 6 of the third switch unit 600 is connected to the emitter of the IGBT tube Q5, the contact 28 of the third switch unit 600 is vacant, the contact 29 of the third switch unit 600 is connected to the gate of the IGBT tube Q5, and the contact 30 of the third switch unit 600 is connected to the gate of the IGBT tube Q5.

[0046] The contact 7 of the third switch unit 600 is connected to the contact 8 of the first switch unit 300 and the contact 17 of the first switch unit 300, the contact 31 of the third switch unit 600 is connected to the collector of the IGBT tube Q6, the contact 32 of the third switch unit 600 is connected to the collector of the IGBT tube Q4, and the contact 33 of the third switch unit 600 is connected to the collector of the IGBT tube Q2.

[0047] The contact 8 of the third switch unit 600 is connected to the contact 10 of the first switch unit 300 and the contact 19 of the first switch unit 300, the contact 34 of the third switch unit 600 is connected to the gate of the IGBT tube Q6, the contact 35 of the third switch unit 600 is connected to the gate of the IGBT tube Q6, and the contact 36 of the third switch unit 600 is connected to the gate of the IGBT tube Q2.

[0048] The contact 9 of the third switch unit 600 is connected to the contact 12 of the first switch unit 300, the contact 15 of the first switch unit 300 and the contact 6 of the first switch unit 300, the contact 37 of the third switch unit 600 is connected to the emitter of the IGBT tube Q6, the contact 38 of the third switch unit 600 is connected to the emitter of the IGBT tube Q4, and the contact 39 of the third switch unit 600 is connected to the emitter of the IGBT tube Q2.

[0049] The contact 10 of the third switch unit 600 is connected to the emitter of the IGBT tube Q2, the contact 40 of the third switch unit 600 is connected to the gate of the IGBT tube Q2, the contact 41 of the third switch unit 600 is connected to the gate of the IGBT tube Q2, and the contact 42 of the third switch unit 600 is vacant.

[0050] The contact 11 of the third switch unit 600 is connected to the emitter of the IGBT tube Q4, the contact 43 of the third switch unit 600 is connected to the gate of the IGBT tube Q4, the contact 44 of the third switch unit 600 is vacant, and the contact 45 of the third switch unit 600 is connected to the gate of the IGBT tube Q6.

[0051] The contact 12 of the third switch unit 600 is connected to the emitter of the IGBT tube Q6, the contact 46 of the third switch unit 600 is vacant, the contact 47 of the third switch unit 600 is connected to the gate of the IGBT tube Q5, and the contact 48 of the third switch unit 600 is connected to the gate of the IGBT tube Q5.

[0052] The upper bridge or the lower bridge is switched by multiple double switches of the first switch unit 300, and one IGBT tube in the upper bridge or the lower bridge is connected by multiple triple switches of the third switch unit 600. Specifically, Take the test of the first phase IGBT tube Q1 and diode FRD2 as an example, the switch settings are the same as Figure 3The positions shown are the same, contact 1 in the first switch unit 300 is connected to contact 9, contact 2 in the first switch unit 300 is connected to contact 11, contact 3 in the first switch unit 300 is connected to contact 13, contact 4 in the first switch unit 300 is connected to contact 15, contact 5 in the first switch unit 300 is connected to contact 17, contact 6 in the first switch unit 300 is connected to contact 19, contact 7 in the first switch unit 300 is connected to contact 21, and contact 1 in the second switch unit 400 is connected to contact 3. In the third switch unit 600, contact 1 is connected to contact 15, contact 2 is connected to contact 18, contact 3 is connected to contact 21, contact 4 is connected to contact 24, contact 5 is connected to contact 27, contact 6 is connected to contact 30, contact 7 is connected to contact 33, contact 8 is connected to contact 36, contact 9 is connected to contact 39, contact 10 is connected to contact 42, contact 11 is connected to contact 45, contact 12 is connected to contact 48, and contact 1 is connected to contact 4 in the third switch unit 70. At this time, sampling points C, G, and E are respectively connected to the collector, gate, and emitter of the upper bridge IGBT tube Q1. Sampling points F and FE are respectively connected to the positive and negative electrodes of the lower bridge diode FRD2. The gate and emitter of the lower bridge IGBT tube Q2 are short-circuited by connecting contact 6 and contact 19 in the first switch unit 300, the gate and emitter of the upper bridge IGBT tube Q3 are short-circuited by connecting contact 5 and contact 27 in the third switch unit 600, the gate and emitter of the upper bridge IGBT tube Q5 are short-circuited by connecting contact 6 and contact 30 in the third switch unit 600, the gate and emitter of the lower bridge IGBT tube Q4 are short-circuited by connecting contact 11 and contact 45 in the third switch unit 600, and the gate and emitter of the lower bridge IGBT tube Q6 are short-circuited by connecting contact 12 and contact 48 in the third switch unit 600. In this way, the gates and emitters of all IGBT tubes except the test IGBT tube are short-circuited to protect them from being mis-conducted. The voltage of each point is obtained through sampling points C, G, E, F, and FE, and the current of IGBT tube Q1 and diode FRD2 is obtained by external current sensor. After the driving power supply VCC voltage is given, the driving signal is given through the DSP signal board, and the driving IC drives the IGBT tube Q1 to open and close, and the voltage and current waveforms of IGBT tube Q1 and diode FRD2 can be obtained for analysis.

[0053] When measuring the IGBT tube Q3 of the upper bridge of the second phase and the diode FRD4 of the lower bridge, it is only necessary to connect the contact 1 and the contact 14 in the third switch unit 600, the contact 2 and the contact 17 in the third switch unit 600, the contact 3 and the contact 20 in the third switch unit 600, the contact 4 and the contact 23 in the third switch unit 600, the contact 5 and the contact 26 in the third switch unit 600, and the contact 6 and the contact 29 in the third switch unit 600. The contact 7 in the third switch unit 600 is connected to the contact 32, the contact 8 in the third switch unit 600 is connected to the contact 35, the contact 9 in the third switch unit 600 is connected to the contact 38, the contact 10 in the third switch unit 600 is connected to the contact 41, the contact 11 in the third switch unit 600 is connected to the contact 44, the contact 12 in the third switch unit 600 is connected to the contact 47, and the contact 1 in the fourth switch unit 700 is connected to the contact 3. At this time, the sampling points C, G, and E are respectively connected to the collector, gate, and emitter of the IGBT tube Q3, and the sampling points F and FE are respectively connected to the positive and negative electrodes of FRD4, so that different IGBT tubes and diodes can be detected by directly switching the switches.

[0054] Compared with the prior art, the double pulse test circuit provided by the present invention realizes the switching of the IGBT under test by adding a first switch unit 300 between the test unit 100 and the module unit 200. Specifically, the first switch unit 300 includes seven double switches, and the seven double switches are respectively connected to the electrodes of multiple IGBT tubes in the module unit 200. The collector, gate, emitter of the IGBT tube under test and the positive and negative electrodes of the diode FRD under test can be switched through multiple double switches, so that the desired IGBT tube under test and the diode FRD under test can be directly switched. In this way, the detection of different IGBT tubes and diodes can be realized by directly switching the switch. The position of the interface and the DSP drive do not need to be changed, avoiding repeated wiring. Only one drive IC is required, and there is no multi-channel signal interference. The position of the interface does not need to be changed, avoiding manual operation to cause signal acquisition errors. In addition, there will be two double switches in the first switch unit 300 to short-circuit the IGBT that is not detected, so that the IGBT that is not detected is short-circuited to protect it, ensuring that it will not be mis-conducted and avoiding parasitic conduction. At the same time, the short-circuit protection of which IGBT can also be quickly switched by the double switch. For the three-bridge test structure, fast switching is achieved by adding a third switch unit 600 and a fourth switch unit 700. The third switch unit 600 includes twelve triple switches (L1~L12). The upper bridge or the lower bridge is switched through the multiple double switches of the first switch unit 300, and one IGBT tube in the upper bridge or the lower bridge is connected through the multiple triple switches of the third switch unit 600 to avoid repeated wiring.

[0055] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modification, equivalent substitution or improvement within the spirit of the present invention is included in the scope of the claims of the present invention.

Claims

1. A double pulse test circuit, characterized in that: The double pulse test circuit includes a test unit, a module unit, a first switch unit electrically connected to the test unit and the module unit, and a second switch unit electrically connected to the module unit. The module unit includes an IGBT tube Q1, an IGBT tube Q2, a diode FRD1, a diode FRD2, a driving power supply VCC, a ground terminal GND, and an inductor Ls. One end of the inductor Ls is connected to the circuit midpoint between the emitter of the IGBT tube Q1 and the collector of the IGBT tube Q2, and the other end of the inductor Ls is connected to the second switch unit. The second switch unit It includes a double switch, the contact 1 of the second switch unit is connected to one end of the inductor Ls, the contact 2 of the second switch unit is connected between the driving power supply VCC and the collector of the IGBT tube Q1, and the contact 3 of the second switch unit is connected between the ground terminal GND and the emitter of the IGBT tube Q2. The inductor Ls is connected to different IGBT tubes by switching the second switch unit. The first switch unit includes seven double switches, and the seven double switches are respectively connected to the electrodes of multiple IGBT tubes in the module unit. By opening different double switches, an IGBT tube is connected for testing.

2. The double pulse test circuit as claimed in claim 1, characterized in that: The test unit includes a DSP signal board, a driver IC connected to the DSP signal board, a C sampling point connected to the driver IC, a G sampling point connected to the driver IC, an E sampling point connected to the driver IC, an F sampling point, and an FE sampling point. The driver IC has three output terminals, namely, a Vc output terminal, a Vg output terminal, and a Ve output terminal. One end of the C sampling point, the G sampling point, and the E sampling point is respectively connected to the Vc output terminal, the Vg output terminal, and the Ve output terminal, and the other end is connected to the collector, the gate, and the emitter of the IGBT under test in the module unit through the first switch unit. One end of the F sampling point and the FE sampling point is connected to the positive electrode and the negative electrode of the diode FRD under test in the module unit through the first switch unit.

3. The double pulse test circuit as claimed in claim 1, characterized in that: The module unit further includes a capacitor C, two ends of which are respectively connected to a ground terminal GND and a driving power supply VCC, and the capacitor C is connected to the circuit as a bus capacitor.

4. The double pulse test circuit as claimed in claim 1, characterized in that: The collector of the IGBT tube Q1 is connected to the driving power supply VCC, the emitter of the IGBT tube Q1 is connected to the collector of the IGBT tube Q2, the emitter of the IGBT tube Q2 is connected to the ground terminal GND, the cathode of the diode FRD1 is connected to the collector of the IGBT tube Q1, the anode of the diode FRD1 is connected to the emitter of the IGBT tube Q1, the cathode of the diode FRD2 is connected to the collector of the IGBT tube Q2, and the anode of the diode FRD2 is connected to the emitter of the IGBT tube Q2, so that the IGBT tube Q1 and the diode FRD1 serve as an upper bridge of the circuit, and the IGBT tube Q2 and the diode FRD2 serve as a lower bridge of the circuit.

5. The double pulse test circuit as claimed in claim 1, characterized in that: The contact 1 of the first switch unit is connected to the test unit, the contact 8 of the first switch unit is connected to the collector of the IGBT tube Q2, the contact 9 of the first switch unit is connected to the collector of the IGBT tube Q1, the contact 2 of the first switch unit is connected to the test unit, the contact 10 of the first switch unit is connected to the gate of the IGBT tube Q2, the contact 11 of the first switch unit is connected to the gate of the IGBT tube Q1, the contact 3 of the first switch unit is connected to the test unit, the contact 12 of the first switch unit is connected to the emitter of the IGBT tube Q2, the contact 13 of the first switch unit is connected to the emitter of the IGBT tube Q1, the contact 4 of the first switch unit is connected to the sampling point F, and the contact 14 of the first switch unit is connected to the sampling point F. The anode of the diode FRD1 is connected, the contact 15 of the first switch unit is connected to the anode of the diode FRD2, the contact 5 of the first switch unit is connected to the sampling point FE, the contact 16 of the first switch unit is connected to the cathode of the diode FRD1, the contact 17 of the first switch unit is connected to the cathode of the diode FRD2, the contact 6 of the first switch unit is connected to the emitter of the IGBT tube Q2, the contact 18 of the first switch unit is vacant, the contact 19 of the first switch unit is connected to the gate of the IGBT tube Q2, the contact 7 of the first switch unit is connected to the emitter of the IGBT tube Q1, the contact 20 of the first switch unit is connected to the gate of the IGBT tube Q1, and the contact 21 of the first switch unit is vacant.

6. The double pulse test circuit as claimed in claim 5, characterized in that: The double pulse test circuit also includes a three-phase bridge module unit, a third switch unit connected to the first switch unit and the three-phase bridge module unit, and a fourth switch unit connected to the three-phase bridge module unit. The three-phase bridge module unit includes IGBT tube Q1, IGBT tube Q2, IGBT tube Q3, IGBT tube Q4, IGBT tube Q5, IGBT tube Q6, diode FRD1, diode FRD2, diode FRD3, diode FRD4, diode FRD5, and diode FRD6.

7. The double pulse test circuit as claimed in claim 6, characterized in that: The fourth switch unit includes a triple switch, wherein the contact 1 of the fourth switch unit is connected to one end of the inductor Ls, the contact 2 of the fourth switch unit is connected to the middle point of the IGBT tube Q5 and the IGBT tube Q6, the contact 3 of the fourth switch unit is connected to the middle point of the IGBT tube Q3 and the IGBT tube Q4, and the contact 4 of the fourth switch unit is connected to the middle point of the IGBT tube Q1 and the IGBT tube Q2. The inductor Ls is connected to the IGBT tube of the upper bridge or the lower bridge by switching of the second switch unit, and is connected to one of the IGBT tubes of the upper bridge or the lower bridge by switching of the fourth switch unit.

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