A dual-pulse test circuit

Abstract

The present invention relates to the technical field of power module test circuits, and particularly to a double-pulse test circuit. It includes a test unit, a module unit, a first switch unit, and a second switch unit. The module unit includes an IGBT tube Q1, an IGBT tube Q2, a diode FRD1, a diode FRD2, and an inductor Ls. The inductor Ls is connected to different IGBT tubes through the switching of the second switch unit. The first switch unit includes seven double-pole switches, and multiple double-pole switches are respectively switchably connected to three poles of the IGBT tube under test and the positive and negative electrodes of the diode FRD under test, directly switching the desired IGBT tube under test and the diode FRD under test. Furthermore, neither the position of the interface nor the DSP drive needs to be changed, avoiding repeated wiring. That is, there is only one drive IC without multi-path signal interference, and the interface position does not need to be changed, avoiding errors in the collected signals caused by manual operation.

Description

Technical Field

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

[0002] IGBT is an abbreviation for insulated gate bipolar transistor, which has the characteristics of low conduction voltage drop and high input impedance. It is often used as a switching device in the field of electronic circuits and 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 for ensuring the reliability and stability of the entire power electronic system. At present, the double-pulse test method is usually adopted to conduct 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, making it easier to simulate the voltage and current changes of the IGBT during application.

[0003] Currently, the double-pulse test method is usually used to test IGBT devices. Most common double-pulse test methods are for testing a single IGBT. When applying it to test IGBT modules with three-phase or half-bridge circuit structures, since it is necessary to test different test modules and test circuits, it is necessary to frequently replace and build the test circuit and frequently change the device positions, resulting in relatively 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 problems.

[0005] A 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 midpoint of the circuit 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 includes a double-pole switch. Contact 1 of the second switch unit is connected to one end of the inductor Ls, contact 2 of the second switch unit is connected between the driving power supply VCC and the collector of the IGBT tube Q1, and contact 3 of the second switch unit is connected between the ground terminal GND and the emitter of the IGBT tube Q2. By switching the second switch unit, the inductor Ls is connected to different IGBT tubes. The first switch unit includes seven double-pole switches, and the seven double-pole switches are respectively connected to the electrodes of multiple IGBT tubes in the module unit. By turning on different double-pole switches, an IGBT tube is connected for testing.

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

[0007] Further, the module unit further includes a capacitor C. Both 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 into the circuit as a bus capacitor.

[0008] Further, the collector of the IGBT transistor Q1 is connected to the driving power supply VCC, the emitter of the IGBT transistor Q1 is connected to the collector of the IGBT transistor Q2, the emitter of the IGBT transistor Q2 is connected to the ground terminal GND, the negative electrode of the diode FRD1 is connected to the collector of the IGBT transistor Q1, the positive electrode of the diode FRD1 is connected to the emitter of the IGBT transistor Q1, the negative electrode of the diode FRD2 is connected to the collector of the IGBT transistor Q2, and the positive electrode of the diode FRD2 is connected to the emitter of the IGBT transistor Q2. In this way, the IGBT transistor Q1 and the diode FRD1 serve as the upper bridge of the circuit, and the IGBT transistor Q2 and the diode FRD2 serve as the lower bridge of the circuit.

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

[0010] Further, the double-pulse test circuit further 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 transistors Q1, Q2, Q3, Q4, Q5, Q6, diodes FRD1, FRD2, FRD3, FRD4, FRD5, and diode FRD6.

[0011] Further, the fourth switch unit includes a triple switch. Contact 1 of the fourth switch unit is connected to one end of the inductor Ls. Contact 2 of the fourth switch unit is connected to the midpoint between IGBT Q5 and IGBT Q6. Contact 3 of the fourth switch unit is connected to the midpoint between IGBT Q3 and IGBT Q4. Contact 4 of the fourth switch unit is connected to the midpoint between IGBT Q1 and IGBT Q2. By switching the second switch unit, the inductor Ls is connected to the IGBTs of the upper bridge or the lower bridge, and by switching the fourth switch unit, the inductor Ls is connected to one IGBT of the upper bridge or the lower bridge.

[0012] Compared with the prior art, the dual-pulse test circuit provided by the present invention realizes the switching of the IGBT to be measured 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 IGBTs in the module unit. The collector, gate, emitter of the IGBT to be measured and the positive and negative electrodes of the diode FRD to be measured can be respectively and switchably connected through the multiple double switches, so that the IGBT to be measured and the diode FRD to be desired can be directly switched. In this way, the detection of different IGBTs and diodes can be realized by directly switching the switches. The position of the interface and the DSP drive do not need to be changed, avoiding repeated wiring. There is only one drive IC, so there is no multi-path signal interference, and the interface position does not need to be changed, avoiding the acquisition signal error caused by manual operation. In addition, two double switches in the first switch unit will short-circuit the IGBTs that are not detected, so that the IGBTs that are not detected are short-circuit protected to ensure that they will not be mis-conducted and avoid parasitic conduction. At the same time, which IGBT is short-circuit protected can also be quickly switched through the double switch. For the three-phase bridge test structure, the rapid switching is realized 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 of the upper bridge or the lower bridge is connected through the multiple triple switches of the third switch unit, avoiding repeated wiring. Description of the Drawings

[0013] Figure 1 It is a principle block diagram of a dual-pulse test circuit provided by the present invention.

[0014] Figure 2 is Figure 1 the circuit diagram of the dual-pulse test circuit.

[0015] Figure 3 is Figure 1 the circuit diagram when the dual-pulse test circuit detects a three-phase circuit. Detailed Embodiments

[0016] The following further elaborates on specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein does not limit the protection scope of the present invention.

[0017] As Figure 1 shown, it is a schematic structural diagram 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 envisioned that the double-pulse test circuit further includes some other functional modules, such as a control module, a data collector, and a power supply module, etc., which are well-known technologies to those skilled in the art and will not be elaborated herein.

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

[0019] The DSP signal, that is, the signal in digital signal processing, refers to the signal that has been digitized. 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 driving IC can drive the module unit 200.

[0020] The driving IC has three output terminals, namely the Vc output terminal, the Vg output terminal, and the Ve output terminal. The driving IC is used to control the digital signal generated by the DSP signal board, convert the digital signal into the driving signal required by the module unit 200, so that it can operate normally.

[0021] One end of the C sampling point, the G sampling point, and the E sampling point are respectively connected to the Vc output terminal, the Vg output terminal, and the Ve output terminal, and the other end is respectively connected to the collector, gate, and 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 are connected to the positive and negative electrodes 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 and negative electrodes of the corresponding diode FRD.

[0022] The module unit 200 includes an IGBT transistor Q1, an IGBT transistor Q2, a diode FRD1, a diode FRD2, a driving power supply VCC, a capacitor C, a ground terminal GND, and an inductor Ls.

[0023] The collector of the IGBT transistor Q1 is connected to the driving power supply VCC, the emitter of the IGBT transistor Q1 is connected to the collector of the IGBT transistor Q2, and the gate of the IGBT transistor Q1 is connected to the first switching unit 300. The emitter of the IGBT transistor Q2 is connected to the ground terminal GND, and the gate of the IGBT transistor Q2 is connected to the first switching unit 300.

[0024] The negative electrode of the diode FRD1 is connected to the collector of the IGBT transistor Q1, and the positive electrode of the diode FRD1 is connected to the emitter of the IGBT transistor Q1. The negative electrode of the diode FRD2 is connected to the collector of the IGBT transistor Q2, and the positive electrode of the diode FRD2 is connected to the emitter of the IGBT transistor Q2. Thus, the IGBT transistor Q1 and the diode FRD1 form an upper bridge of the circuit, and the IGBT transistor Q2 and the diode FRD2 form a lower bridge of the circuit, and further the IGBT transistor Q1, the IGBT transistor Q2, the diode FRD1, and the diode FRD2 form a half-bridge circuit.

[0025] Both ends of the capacitor C are respectively connected to the ground terminal GND and the driving power supply VCC. 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, thereby improving the stability and reliability of the motor controller.

[0026] The inductor Ls is connected to the circuit as an inductive load. One end of the inductor Ls is connected to the midpoint of the circuit between the emitter of the IGBT transistor Q1 and the collector of the IGBT transistor Q2, and the other end of the inductor Ls is connected to the second switching unit 400.

[0027] The second switching unit 400 includes a double-pole switch. Contact 1 of the second switching unit 400 is connected to the other end of the inductor Ls, and contact 2 of the second switching unit 400 is connected between the driving power supply VCC and the collector of the IGBT transistor Q1. Contact 3 of the second switching unit 400 is connected between the ground terminal GND and the emitter of the IGBT transistor Q2. By switching the second switching unit 400, the inductor Ls is connected to different IGBT transistors. When detecting the IGBT transistor Q1, contact 1 of the second switching unit 400 is connected to contact 3, and when detecting the IGBT transistor Q2, contact 1 of the second switching unit 400 is connected to contact 2.

[0028] The first switch unit 300 includes seven double-pole switches (K1~K7). The seven double-pole switches are respectively connected to the electrodes of multiple IGBT tubes in the module unit 200. By turning on different double-pole switches, one 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 drive 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. The contact 9 of the first switch unit 300 is connected to the collector of the IGBT tube Q1.

[0029] The contact 2 of the first switch unit 300 is connected to the Vg output terminal of the drive 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. The contact 11 of the first switch unit 300 is connected to the gate of the IGBT tube Q1.

[0030] The contact 3 of the first switch unit 300 is connected to the Ve output terminal of the drive 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. The contact 13 of the first switch unit 300 is connected to the emitter of the IGBT tube Q1.

[0031] 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 positive electrode of the diode FRD1. The contact 15 of the first switch unit 300 is connected to the positive electrode of the diode FRD2.

[0032] 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 negative electrode of the diode FRD1. The contact 17 of the first switch unit 300 is connected to the negative electrode of the diode FRD2.

[0033] 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. The contact 19 of the first switch unit 300 is connected to the gate of the IGBT tube Q2.

[0034] 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. The contact 21 of the first switch unit 300 is vacant.

[0035] The collector, gate, and emitter of the IGBT under test and the positive and negative electrodes of the diode FRD under test are respectively switchably connected through multiple double-pole switches, so that the desired IGBT under test and the diode FRD under test can be directly switched. Among them, the contacts 6 and 7 of the first switch unit 300 are used to short-circuit and protect another IGBT during detection. Specifically, taking the test of IGBT Q1 and diode FRD2 as an example, the switch settings are the same as Figure 2 the positions shown. In the first switch unit 300, contact 1 is connected to contact 9, contact 2 is connected to contact 11, contact 3 is connected to contact 13, contact 4 is connected to contact 15, contact 5 is connected to contact 17, contact 6 is connected to contact 19, contact 7 is connected to contact 21, and at the same time, contact 1 of the second switch unit 400 is connected to contact 3. At this time, the sampling points C, G, and E are respectively connected to the collector, gate, and emitter of the IGBT Q1, and the sampling points F and FE are respectively connected to the positive and negative electrodes of FRD2. By connecting contact 6 and contact 19 in the first switch unit 300 to short-circuit the gate and emitter of IGBT Q2, IGBT Q2 is always turned off to ensure that it will not be mis-conducted. The voltages at each point are obtained through the sampling points C, G, E, F, and FE, and at the same time, an external current sensor is used to obtain the currents of IGBT Q1 and diode FRD2. After applying the driving power supply VCC voltage, a driving signal is given through the DSP signal board, and the driving IC drives IGBT Q1 to open and close, so that the voltage and current waveforms of IGBT Q1 and diode FRD2 can be obtained simultaneously for analysis. It can be imagined that the voltage and current waveforms are collected by a data collector.

[0036] When testing the IGBT transistor Q2 and the diode FRD1, only need to connect contact 1 and contact 8 in the first switch unit 300, connect contact 2 and contact 10 in the first switch unit 300, connect contact 3 and contact 12 in the first switch unit 300, connect contact 4 and contact 14 in the first switch unit 300, connect contact 5 and contact 16 in the first switch unit 300, connect contact 6 and contact 18 in the first switch unit 300, connect contact 7 and contact 20 in the first switch unit 300, and at the same time connect contact 1 and contact 2 in the second switch unit 400. At this time, the sampling points C, G, and E are respectively connected to the collector, gate, and emitter of the IGBT transistor Q2, and the sampling points F and FE are respectively connected to the positive and negative electrodes of the FRD1, so that different IGBT transistors and diodes can be detected by directly switching the switches. The position of the interface and the DSP drive do not need to be changed. After applying the driving power supply VCC voltage, a driving signal is given through the DSP signal board, and the driving IC drives the IGBT transistor Q2 to open and close, so that the voltage and current waveforms of the IGBT transistor Q2 and the diode FRD1 can be obtained simultaneously for analysis. During the test process, 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 there is only one driving IC without multi-channel signal interference. The interface position does not need to be changed, avoiding the error of the collected signal caused by manual operation. The electronic components that are not tested are short-circuited to protect against parasitic conduction.

[0037] Second embodiment.

[0038] For testing other bridge circuits such as the three-phase bridge test structure, detection can be achieved by adding a switch group, as Figure 3 shown, which is a circuit schematic diagram when the double-pulse test 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.

[0039] 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. Therefore, four IGBT transistors and four diodes FRD are added to form a three-phase circuit. The three-phase bridge module unit 500 includes IGBT transistor Q1, IGBT transistor Q2, IGBT transistor Q3, IGBT transistor Q4, IGBT transistor Q5, IGBT transistor 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 prior art and will not be elaborated here.

[0040] The fourth switch unit 700 includes a triple switch. Contact 1 of the fourth switch unit 700 is connected to one end of the inductor Ls. Contact 2 of the fourth switch unit 700 is connected to the midpoint between IGBT transistor Q5 and IGBT transistor Q6. Contact 3 of the fourth switch unit 700 is connected to the midpoint between IGBT transistor Q3 and IGBT transistor Q4. Contact 4 of the fourth switch unit 700 is connected to the midpoint between IGBT transistor Q1 and IGBT transistor Q2. By switching through the second switch unit 400, the inductor Ls is connected to the IGBT transistors of the upper bridge or the lower bridge. And by switching through the fourth switch unit 700, the inductor Ls is connected to one IGBT transistor of the upper bridge or the lower bridge, so as to realize the load connection of a single IGBT transistor in the three-phase circuit.

[0041] The third switch unit 600 includes twelve triple switches (L1~L12). Specifically, contact 1 of the third switch unit 600 is connected to contact 9 and contact 16 of the first switch unit 300. Contact 13 of the third switch unit 600 is connected to the collector of IGBT transistor Q5. Contact 14 of the third switch unit 600 is connected to the collector of IGBT transistor Q3. Contact 15 of the third switch unit 600 is connected to the collector of IGBT transistor Q1.

[0042] Contact 2 of the third switch unit 600 is connected to contact 11 and contact 20 of the first switch unit 300. Contact 16 of the third switch unit 600 is connected to the gate of IGBT transistor Q5. Contact 17 of the third switch unit 600 is connected to the gate of IGBT transistor Q3. Contact 18 of the third switch unit 600 is connected to the gate of IGBT transistor Q1.

[0043] Contact 3 of the third switch unit 600 is connected to contact 13, contact 14, and contact 7 of the first switch unit 300. Contact 19 of the third switch unit 600 is connected to the emitter of IGBT Q5. Contact 20 of the third switch unit 600 is connected to the emitter of IGBT Q3. Contact 21 of the third switch unit 600 is connected to the emitter of IGBT Q1.

[0044] Contact 4 of the third switch unit 600 is connected to the emitter of IGBT Q1. Contact 22 of the third switch unit 600 is connected to the gate of IGBT Q1. Contact 23 of the third switch unit 600 is connected to the gate of IGBT Q1. Contact 24 of the third switch unit 600 is left open.

[0045] Contact 5 of the third switch unit 600 is connected to the emitter of IGBT Q3. Contact 25 of the third switch unit 600 is connected to the gate of IGBT Q3. Contact 26 of the third switch unit 600 is left open. Contact 27 of the third switch unit 600 is connected to the gate of IGBT Q3.

[0046] Contact 6 of the third switch unit 600 is connected to the emitter of IGBT Q5. Contact 28 of the third switch unit 600 is left open. Contact 29 of the third switch unit 600 is connected to the gate of IGBT Q5. Contact 30 of the third switch unit 600 is connected to the gate of IGBT Q5.

[0047] Contact 7 of the third switch unit 600 is connected to contact 8 and contact 17 of the first switch unit 300. Contact 31 of the third switch unit 600 is connected to the collector of IGBT Q6. Contact 32 of the third switch unit 600 is connected to the collector of IGBT Q4. Contact 33 of the third switch unit 600 is connected to the collector of IGBT Q2.

[0048] Contact 8 of the third switch unit 600 is connected to contact 10 and contact 19 of the first switch unit 300. Contact 34 of the third switch unit 600 is connected to the gate of IGBT Q6. Contact 35 of the third switch unit 600 is connected to the gate of IGBT Q6. Contact 36 of the third switch unit 600 is connected to the gate of IGBT Q2.

[0049] The contact 9 of the third switch unit 600 is connected to the contact 12, the contact 15, 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 Q6. The contact 38 of the third switch unit 600 is connected to the emitter of the IGBT Q4. The contact 39 of the third switch unit 600 is connected to the emitter of the IGBT Q2.

[0050] The contact 10 of the third switch unit 600 is connected to the emitter of the IGBT Q2. The contact 40 of the third switch unit 600 is connected to the gate of the IGBT Q2. The contact 41 of the third switch unit 600 is connected to the gate of the IGBT Q2. The contact 42 of the third switch unit 600 is left open.

[0051] The contact 11 of the third switch unit 600 is connected to the emitter of the IGBT Q4. The contact 43 of the third switch unit 600 is connected to the gate of the IGBT Q4. The contact 44 of the third switch unit 600 is left open. The contact 45 of the third switch unit 600 is connected to the gate of the IGBT Q4.

[0052] The contact 12 of the third switch unit 600 is connected to the emitter of the IGBT Q6. The contact 46 of the third switch unit 600 is left open. The contact 47 of the third switch unit 600 is connected to the gate of the IGBT Q6. The contact 48 of the third switch unit 600 is connected to the gate of the IGBT Q6.

[0053] The switching between the upper bridge and the lower bridge is performed by multiple double-pole switches of the first switch unit 300, and the connection of one IGBT in the upper bridge or the lower bridge is performed by multiple triple-pole switches of the third switch unit 600. Specifically,

[0054] Taking the IGBT Q1 and the diode FRD2 of the first phase as an example for testing, the switch settings are the same as Figure 3At the same position as shown, 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. At the same time, contact 1 in the second switch unit 400 is connected to contact 3. Contact 1 in the third switch unit 600 is connected to contact 15, contact 2 in the third switch unit 600 is connected to contact 18, contact 3 in the third switch unit 600 is connected to contact 21, contact 4 in the third switch unit 600 is connected to contact 24, contact 5 in the third switch unit 600 is connected to contact 27, contact 6 in the third switch unit 600 is connected to contact 30, contact 7 in the third switch unit 600 is connected to contact 33, contact 8 in the third switch unit 600 is connected to contact 36, contact 9 in the third switch unit 600 is connected to contact 39, contact 10 in the third switch unit 600 is connected to contact 42, contact 11 in the third switch unit 600 is connected to contact 45, contact 12 in the third switch unit 600 is connected to contact 48. At the same time, contact 1 in the third switch unit 70 is connected to contact 4. At this time, the sampling points C, G, and E are respectively connected to the collector, gate, and emitter of the IGBT tube Q1 on the upper bridge. The sampling point F and the sampling point FE are respectively connected to the positive and negative electrodes of the diode FRD2 on the lower bridge. The gate and emitter of the IGBT tube Q2 on the lower bridge are short-circuited through the connection between contact 6 and contact 19 in the first switch unit 300. The gate and emitter of the IGBT tube Q3 on the upper bridge are short-circuited through the connection between contact 5 and contact 27 in the third switch unit 600. The gate and emitter of the IGBT tube Q5 on the upper bridge are short-circuited through the connection between contact 6 and contact 30 in the third switch unit 600. The gate and emitter of the IGBT tube Q4 on the lower bridge are short-circuited through the connection between contact 11 and contact 45 in the third switch unit 600. The gate and emitter of the IGBT tube Q6 on the lower bridge are short-circuited through the connection between contact 12 and contact 48 in the third switch unit 600. In this way, the gates and emitters of all IGBT tubes except the tested IGBT tubes are short-circuited and protected to ensure that there will be no mis-conduction. The voltages at each point are obtained through the sampling points C, G, E, F, and FE. At the same time, an external current sensor is used to obtain the currents of the IGBT tube Q1 and the diode FRD2. After applying the driving power supply VCC voltage, a driving signal is given through the DSP signal board, and the driving IC drives the IGBT tube Q1 to open and close, so that the voltage and current waveforms of the IGBT tube Q1 and the diode FRD2 can be obtained simultaneously for analysis.

[0055] When measuring the IGBT Q3 on the upper bridge and the diode FRD4 on the lower bridge of the second phase, only need to connect contact 1 and contact 14 in the third switch unit 600, connect contact 2 and contact 17 in the third switch unit 600, connect contact 3 and contact 20 in the third switch unit 600, connect contact 4 and contact 23 in the third switch unit 600, connect contact 5 and contact 26 in the third switch unit 600, connect contact 6 and contact 29 in the third switch unit 600, connect contact 7 and contact 32 in the third switch unit 600, connect contact 8 and contact 35 in the third switch unit 600, connect contact 9 and contact 38 in the third switch unit 600, connect contact 10 and contact 41 in the third switch unit 600, connect contact 11 and contact 44 in the third switch unit 600, connect contact 12 and contact 47 in the third switch unit 600, and at the same time connect contact 1 and contact 3 in the fourth switch unit 700. At this time, the sampling points C, G, and E are respectively connected to the collector, gate, and emitter of the IGBT Q3, and the sampling points F and FE are respectively connected to the positive and negative electrodes of the FRD4, so that different IGBTs and diodes can be detected by directly switching the switches.

[0056] Compared with the prior art, the dual-pulse test circuit provided by the present invention realizes the switching of the IGBT to be measured by adding the first switch unit 300 between the test unit 100 and the module unit 200. Specifically, the first switch unit 300 includes seven double-pole switches, and the seven double-pole switches are respectively connected to the electrodes of multiple IGBTs in the module unit 200. The collector, gate, emitter of the IGBT to be measured and the positive and negative electrodes of the diode FRD to be measured can be respectively switched and connected through the multiple double-pole switches, so that the IGBT to be measured and the diode FRD to be measured that are desired can be directly switched. In this way, different IGBTs and diodes can be detected by directly switching the switches. The position of the interface and the DSP drive do not need to be changed, avoiding repeated wiring. Only one drive IC is required, there is no interference of multiple signals, the position of the interface does not need to be changed, and the error of the collected signal caused by manual operation is avoided. In addition, in the first switch unit 300, two double-pole switches will short-circuit the IGBTs that are not detected, so that the IGBTs that are not detected are short-circuit protected to ensure that they will not be mis-conducted and parasitic conduction is avoided. At the same time, which IGBT is short-circuit protected can also be quickly switched through the double-pole switch. For the three-phase bridge test structure, the third switch unit 600 and the fourth switch unit 700 are added to achieve fast switching. The third switch unit 600 includes twelve triple switches (L1~L12). The upper bridge or the lower bridge is switched through the multiple double-pole 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, avoiding repeated wiring.

[0057] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions or improvements within the spirit of the present invention are all covered within 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 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. The second switch unit includes a double switch, and the contact 1 of the second switch unit is connected to the other 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 contact 1 of the second switch unit is connected to the contact 2 or 3 of 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. The collector of the IGBT tube Q1 is connected to the driving power supply VCC, and the emitter of the IGBT tube Q1 is connected to The collector of the IGBT tube Q2 is connected, 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. In this way, the IGBT tube Q1 and the diode FRD1 serve as the upper bridge of the circuit, and the IGBT tube Q2 and the diode FRD2 serve as the lower bridge of the circuit. The contact 1 of the first switch unit is connected to the test unit, and the contact 8 of the first switch unit is connected to the IGBT tube Q1. The collector of IGBT Q2, the contact 9 of the first switch unit is connected to the collector of IGBT 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 IGBT Q2, the contact 11 of the first switch unit is connected to the gate of IGBT 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 IGBT Q2, the contact 13 of the first switch unit is connected to the emitter of IGBT Q1, the contact 4 of the first switch unit is connected to the sampling point F, the contact 14 of the first switch unit is connected to the anode of diode FRD1, and the contact 15 of the first switch unit is connected to the anode of 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, and the contact 19 of the first switch unit is connected to the gate of the IGBT tube Q2. Point 20 is connected to the gate of IGBT tube Q1, contact 21 of the first switch unit is vacant, contact 1 of the first switch unit is connected to contact 8 or 9, contact 2 of the first switch unit is connected to contact 10 or 11, contact 3 of the first switch unit is connected to contact 12 or 13, contact 4 of the first switch unit is connected to contact 14 or 15, contact 5 of the first switch unit is connected to contact 16 or 17, contact 6 of the first switch unit is connected to contact 18 or 19, and contact 7 of the first switch unit is connected to contact 20 or 21.

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 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.

5. The double pulse test circuit as claimed in claim 4, 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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