A loop-symmetrical switching device double-pulse test laminated busbar and test system

Abstract

A loop-symmetrical switching device double-pulse test laminated busbar and test system, belonging to the technical field of switching device testing, solves the problem of how to reduce the stray inductance of the laminated busbar. When performing a double-pulse test on a SiC-based switching device, on the upper and lower surfaces of the laminated busbar, the current of the test loop flows from one side of the two parts divided by the insulating slot through a connecting assembly to the other side of the two parts divided by the insulating slot, thereby passing through the corresponding flexible coil current sensor to complete the collection of the loop current. On the upper and lower surfaces of the laminated busbar, the path of the equivalent current forms a loop that is symmetrical in top and bottom. The currents in the loop are equal in magnitude and opposite in direction, and the magnetic fields generated by the currents in the loop cancel each other out, thereby minimizing the current residual loop and reducing the loop stray inductance. The laminated busbar occupies a small space.

Description

Technical Field

[0001] The invention belongs to the technical field of switch device testing, and relates to a loop-symmetrical switch device double-pulse testing laminated busbar and a testing system. Background Art

[0002] With the rapid development of the semiconductor industry, traditional silicon (Si)-based switching devices, due to inherent material limitations, have struggled to meet the high-frequency, high-power, and low-loss performance requirements of power electronics. Compared to traditional Si-based switching devices, silicon carbide (SiC)-based switching devices, as wide-bandgap devices, have attracted widespread attention due to their advantages such as high-voltage and high-temperature resistance, low on-resistance, and fast switching speeds.

[0003] 1. Double pulse test of switching devices

[0004] Double-pulse testing is a widely used test method for evaluating the characteristics of switching devices, such as IGBTs and other power switching devices. This method not only evaluates the switching characteristics of the device under test, but also the reverse recovery characteristics of the fast recovery diodes (FRDs) used with IGBTs. It is particularly effective for evaluating circuits where reverse recovery characteristics cause losses during conduction.

[0005] like Figure 12 As shown, a double-pulse test applies two pulses as drive control signals to the switch device under test. The falling edge of the first pulse serves as the observation moment for the turn-off process, while the rising edge of the second pulse serves as the observation moment for the turn-on process. The significance of double-pulse testing of switch devices lies in: 1) comparing the parameters of different switch devices; 2) evaluating the functionality and performance of the switch device driver board; 3) obtaining the key parameters of the switch device during the turn-on and turn-off processes to assess whether the Rgon and Rgoff values ​​are appropriate. We often understand a switch device primarily by reading its datasheet. However, the parameters described in the datasheet are actually derived from testing of a set of external parameters. Actual external parameters in applications are individual and often vary, so some of these parameters cannot be directly applied. We need to understand the actual performance of the switch device in a specific application; 4) whether there is any inappropriate oscillation during the turn-on and turn-off processes; 5) evaluating the reverse recovery behavior and safety margin of the diode; 6) whether the voltage spike during the turn-off of the switch device is appropriate and whether there is any inappropriate oscillation after the turn-off process; 7) evaluating the current sharing characteristics of parallel switch devices; and 8) measuring the stray inductance of the busbar.

[0006] 2. Disadvantages of traditional Rogowski coil intervention

[0007] In double-pulse testing, the power switching devices under test, such as IGBTs, typically have a half-bridge structure, requiring two current sensors to measure the current in the upper and lower arms, respectively. Traditionally, current sensors for laminated busbars are connected by connecting wires across the upper and lower surfaces of the busbar. These wires pass through Rogowski coils on these surfaces to detect the current flowing through them. This approach increases the length of the test circuit, disrupting the perfectly symmetrical structure of the upper and lower surfaces of the laminated busbar. Furthermore, at the point where the Rogowski coils are inserted, the distance between the equivalent current paths increases, introducing additional stray inductance.

[0008] 3. Impact of stray inductance energy storage on switching devices

[0009] During double-pulse testing of switching devices, line stray inductance exists in the peripheral test circuit. As switching devices operate at higher voltages, higher currents, and higher switching frequencies, the impact of voltage spikes caused by stray inductance becomes increasingly significant. Rapid shutdown of switching devices generates large di / dt. Therefore, the presence of stray inductance in the test circuit creates voltage spikes at both ends of the switching device. These voltage spikes can breakdown the switching device, causing damage. This is particularly severe for high-frequency switching devices such as those based on silicon carbide.

[0010] Stray inductance stores energy in the magnetic field. The formula for calculating the energy storage of stray inductance magnetic field is: , where I refers to the rated current, Refers to the stray inductance of the line. Since the rated current is set according to customer needs and cannot be changed, the only way to reduce the stray inductance magnetic field energy storage is to reduce it as much as possible. value.

[0011] Therefore, it is urgent to design a laminated busbar with low stray inductance to meet the double pulse test requirements of SiC-based switching devices. Summary of the Invention

[0012] The purpose of the present invention is to design a laminated busbar with low stray inductance to meet the double pulse test requirements of SiC-based switching devices.

[0013] The present invention solves the above technical problems through the following technical solutions:

[0014] A loop-symmetrical switching device double-pulse test laminate busbar comprises: a first copper-clad plate (11), a second copper-clad plate (12), a first connecting component (13), a second connecting component (14), a first flexible coil current sensor (15), and a second flexible coil current sensor (16) covered on the upper and lower surfaces of a dielectric substrate (10); a first insulating groove and a second insulating groove for horizontally mounting the first flexible coil current sensor (15) and the second flexible coil current sensor (16) are respectively provided on the first copper-clad plate (11) and the second copper-clad plate (12); the first insulating groove divides the first copper-clad plate (11) into two parts; the first connecting component (13) crosses the first flexible coil current sensor (15) to connect the two parts of the first copper-clad plate (11) divided by the first insulating groove; the second insulating groove divides the second copper-clad plate (12) into two parts; and the second connecting component (14) crosses the second flexible coil current sensor (16) to connect the two parts of the second copper-clad plate (12) divided by the second insulating groove.

[0015] During double-pulse testing of SiC-based switching devices, the current in the test loop flows from one side of the two parts divided by the insulation slot through the connecting assembly on the top and bottom surfaces of the laminated busbar to the other side of the two parts divided by the insulation slot, thereby passing through the corresponding flexible coil current sensor to complete the loop current acquisition. On the top and bottom surfaces of the laminated busbar, the path of the equivalent current forms a vertically symmetrical loop with equal current magnitude and opposite direction. According to the right-hand rule, the magnetic fields generated by the currents in the loop cancel each other out, so the stray inductance introduced by the loop can be equivalent to zero. The intervention of this flexible coil current sensor minimizes the residual current loop and significantly reduces the stray inductance of the loop, meeting the requirements of double-pulse testing of SiC-based switching devices.

[0016] In one embodiment, the projections of the first insulating groove and the second insulating groove perpendicular to the paper surface overlap.

[0017] Furthermore, the projections of the first flexible coil current sensor (15) and the second flexible coil current sensor (16) perpendicular to the paper surface overlap.

[0018] In one embodiment, the first insulating groove comprises: a first arc-shaped insulating installation groove (110), a first upper insulating gap (111), and a first lower insulating gap (112); the first upper insulating gap (111), the first arc-shaped insulating installation groove (110), and the first lower insulating gap (112) are connected end to end in sequence, dividing the first copper-clad plate (11) into a first protruding block (113) and a first recessed block (114); the second insulating groove comprises: a second arc-shaped insulating installation groove (120), a second upper insulating gap (121), and a second lower insulating gap (122); the second upper insulating gap (121), the second arc-shaped insulating installation groove (120), and the second lower insulating gap (122) are connected end to end in sequence, dividing the second copper-clad plate (12) into a second protruding block (123) and a second recessed block (124).

[0019] In one embodiment, the first flexible coil current sensor and the second flexible coil current sensor both use Rogowski coils.

[0020] In one embodiment, the dielectric substrate (10) is a PCB board.

[0021] In one embodiment, the first connecting assembly (13) and the second connecting assembly (14) both use a plurality of parallel welding pins, and the plurality of parallel welding pins form an arc-shaped welding pin row.

[0022] A double-pulse test system for a switching device using the above-mentioned laminated busbar comprises: a supporting capacitor C, a solid-state switch KT, a first switch K1, and a second switch K2; the positive electrode of the supporting capacitor C is connected to one end of the solid-state switch KT, the other end of the solid-state switch KT is connected to the first copper-clad plate (11) of the laminated busbar, and the negative electrode of the supporting capacitor C is connected to the second copper-clad plate (12); after the first switch K1 and the second switch K2 are connected in series, the non-series end of the first switch K1 is connected to the common connection point between the solid-state switch KT and the first copper-clad plate (11), and the non-series end of the second switch K2 is connected to the common connection point between the supporting capacitor C and the second copper-clad plate (12).

[0023] Furthermore, the double-pulse test system for the switching device of the laminated busbar further includes: a switch tube Q1, a switch tube Q2, and an inductive load L; the switch tube Q1 and the switch tube Q2 form a half-bridge structure, the collector of the switch tube Q1 is connected to the first copper-clad plate (11), and the emitter of the switch tube Q2 is connected to the second copper-clad plate (12); one end of the inductive load L is connected to the midpoint of the half-bridge structure, and the other end of the inductive load L is connected to the series common point of the first switch K1 and the second switch K2.

[0024] In one embodiment, the method for testing the switch tube Q1 and the fast recovery diode D2 is as follows:

[0025] (1) Open the first switch K1 and close the second switch K2, and apply a double pulse waveform to the gate of the switch tube Q1;

[0026] (2) During the time period t1, the switch tube Q1 is turned on, and the current path is: the positive electrode of the supporting capacitor C → the solid-state switch KT → the first copper-clad plate 11 of the laminated busbar → the switch tube Q1 → the inductive load L → the second switch K2 → the negative electrode of the supporting capacitor C. At this time, the first flexible coil current sensor 15 installed on the first copper-clad plate 11 of the laminated busbar collects the current signal of the current path;

[0027] (3) During the time period t2, the switch tube Q1 is turned off, and the fast recovery diode D2 is freewheeling. The current path is: the right end of the inductive load L → the second switch K2 → the second copper clad plate 12 of the laminated busbar → the fast recovery diode D2 → the left end of the inductive load L. At this time, the second flexible coil current sensor 16 installed on the second copper clad plate 12 of the laminated busbar collects the current signal of the current path;

[0028] (4) During the t3 period, the switch tube Q1 is turned on, and a reverse voltage is applied to the fast recovery diode D2, causing it to turn off. The current path during the t3 period is the same as that during the t1 period.

[0029] The advantages of the present invention are:

[0030] (1) When conducting a double-pulse test on SiC-based switching devices, on the upper and lower surfaces of the laminated busbar, the current of the test loop flows from one side of the two parts divided by the insulation slot through the connecting component to the other side of the two parts divided by the insulation slot, thereby passing through the corresponding flexible coil current sensor to complete the collection of the loop current; on the upper and lower surfaces of the laminated busbar, the path of the equivalent current forms a symmetrical loop with equal magnitude and opposite direction in the loop. According to the right-hand rule, the magnetic fields generated by the currents in the loop cancel each other out, so the stray inductance introduced by the loop can be equivalent to zero; this flexible coil current sensor intervention method minimizes the current residual loop to the maximum extent, greatly reduces the stray inductance of the loop, and meets the double-pulse test requirements of SiC-based switching devices;

[0031] (2) The arc-shaped welding pin row used is composed of multiple welding pins arranged in parallel to form an arc. The stray inductance introduced by the welding pins themselves is reduced after being connected in parallel. When the arc-shaped current flows from the convex block (concave block) through the arc-shaped welding pin row and into the concave block (convex block), it is equivalent to a straight wire passing through the center of the flexible coil current sensor, and the sampled current data is more accurate;

[0032] (3) The flexible coil current sensor is placed horizontally, which reduces the space occupied by the laminated busbar and makes the dual pulse test system miniaturized. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the upper surface structure of the laminated busbar according to the first embodiment of the present invention;

[0034] Figure 2 Schematic diagram of the lower surface structure of the laminated busbar according to the first embodiment of the present invention;

[0035] Figure 3 is a side view of a laminated busbar according to a first embodiment of the present invention;

[0036] Figure 4 Schematic diagram of the structure of the first copper clad plate of the laminated busbar in the first embodiment of the present invention;

[0037] Figure 5 Schematic diagram of the structure of the second copper clad plate of the laminated busbar in embodiment 1 of the present invention;

[0038] Figure 6 Schematic diagram of the installation of the first copper-clad plate and the first flexible coil current sensor of the laminated busbar according to the first embodiment of the present invention;

[0039] Figure 7 Schematic diagram of the installation of the second copper-clad plate and the second flexible coil current sensor of the laminated busbar in the first embodiment of the present invention;

[0040] Figure 8 This is a schematic diagram of the installation of the first copper-clad laminate, the first flexible coil current sensor, and the first arc-shaped welding pin row of the laminated busbar according to the first embodiment of the present invention;

[0041] Figure 9 This is a schematic diagram of the installation of the second copper-clad laminate, the second flexible coil current sensor, and the second arc-shaped welding pin row of the laminated busbar according to the first embodiment of the present invention;

[0042] Figure 10 Schematic diagram of a symmetrical current equivalent circuit of a laminated busbar according to the first embodiment of the present invention;

[0043] Figure 11 1 is a schematic structural diagram of a double-pulse test system for a switching device according to a second embodiment of the present invention;

[0044] Figure 12 This is a double pulse waveform diagram of a double pulse test of a switching device according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] The technical solution of the present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0047] Example 1

[0048] like Figure 1 、 Figure 2 (Will Figure 1 With the x-axis as the axis, rotate 180° clockwise to get Figure 2 )and Figure 3 As shown, a double-pulse test laminate busbar for switching devices with symmetrical test loops includes: a dielectric substrate 10, a first copper-clad laminate 11, a second copper-clad laminate 12, a first connecting component 13, a second connecting component 14, a first flexible coil current sensor 15, and a second flexible coil current sensor 16; the dielectric substrate 10 is a rectangular PCB board, and the first copper-clad laminate 11 and the second copper-clad laminate 12 are two identical rectangular copper-clad laminates, with the first copper-clad laminate 11 covering the upper surface of the rectangular PCB board, and the second copper-clad laminate 12 covering the lower surface of the rectangular PCB board.

[0049] like Figure 4 As shown, the first copper clad laminate 11 is etched with a first arc-shaped insulating mounting groove 110, a first upper insulating gap 111 and a first lower insulating gap 112; the first upper insulating gap 111, the first arc-shaped insulating mounting groove 110 and the first lower insulating gap 112 are connected in sequence from end to end, dividing the first copper clad laminate 11 into two parts: a first protruding block 113 and a first recessed block 114.

[0050] like Figure 5 As shown, the second copper clad laminate 12 is etched with a second arc-shaped insulating mounting groove 120, a second upper insulating gap 121 and a second lower insulating gap 122; the second upper insulating gap 121, the second arc-shaped insulating mounting groove 120 and the second lower insulating gap 122 are connected end to end in sequence, dividing the second copper clad laminate 12 into two parts: a second protruding block 123 and a second recessed block 124.

[0051] like Figure 6 and Figure 7 (Will Figure 6 With the x-axis as the axis, rotate 180° clockwise to get Figure 7), the first flexible coil current sensor 15 and the second flexible coil current sensor 16 are horizontally and symmetrically installed in the first arc-shaped insulating mounting groove 110 of the first copper-clad plate 11 and the second arc-shaped insulating mounting groove 120 of the second copper-clad plate 12 respectively.

[0052] like Figure 8 As shown, the first connecting component 13 spans the two sides of the first arc-shaped insulating mounting groove 110 of the first copper clad laminate 11, and is used to connect the first protruding block 113 and the first recessed block 114; the inner edge end of the first connecting component 13 is welded to the first protruding block 113 of the first copper clad laminate 11, and the outer edge end of the first connecting component 13 is welded to the first recessed block 114 of the first copper clad laminate 11.

[0053] like Figure 9 (Will Figure 8 With the x-axis as the axis, rotate 180° clockwise to get Figure 9 ), the second connecting component 14 is connected across the two sides of the second arc-shaped insulating mounting groove 120 of the second copper clad laminate 12, and is used to connect the second protruding block 123 and the second recessed block 124; the inner edge end of the second connecting component 14 is welded to the second protruding block 123 of the second copper clad laminate 12, and the outer edge end of the second connecting component 14 is welded to the second recessed block 124 of the second copper clad laminate 12.

[0054] The first connecting component 13 and the second connecting component 14 both use multiple parallel welding pins, which cross the flexible coil current sensor. One end of the welding pin is welded to the protruding block, and the other end of the welding pin is welded to the recessed block. Multiple parallel welding pins constitute an arc-shaped welding pin row. The stray inductance introduced by the welding pins themselves is reduced after being connected in parallel. The arc-shaped arrangement can make the current flow from the protruding block (recessed block) through the arc-shaped welding pin row into the recessed block (protruding block), which is equivalent to a straight wire passing through the center of the flexible coil current sensor, and the sampled current data is more accurate.

[0055] Working principle of laminated busbar:

[0056] like Figure 1 、 Figure 2 and Figure 4 、 Figure 5 As shown, when performing a double pulse test on a SiC-based switching device, on the upper surface of the laminated busbar, the current of the test loop flows through the first protruding block 113, the first connecting component 13, and the first recessed block 114 of the first copper-clad laminate 11 in sequence, thereby passing through the first flexible coil current sensor 15 to complete the current detection; on the lower surface of the laminated busbar, the current of the test loop flows through the second recessed block 124, the second connecting component 14, and the second protruding block 123 of the second copper-clad laminate 12 in sequence, thereby passing through the second flexible coil current sensor 16 to complete the current detection.

[0057] like Figure 10 As shown in the figure, during the double-pulse test of SiC-based switching devices, the equivalent current path forms a vertically symmetrical loop on the upper and lower surfaces of the laminated busbar. The currents in the loop are equal in magnitude and opposite in direction. According to the right-hand rule, the magnetic fields generated in the loop cancel each other out. Therefore, the stray inductance introduced by the loop can be equivalent to zero.

[0058] Example 2

[0059] like Figure 11 As shown, a double-pulse test system for a switching device includes: a supporting capacitor C, a solid-state switch KT, a laminated busbar, a switch tube Q1, a switch tube Q2, a fast recovery diode D1, a fast recovery diode D2, an inductive load L, a first switch K1, and a second switch K2; the positive electrode of the supporting capacitor C is connected to one end of the solid-state switch KT, the other end of the solid-state switch KT is connected to the left end of the first copper-clad plate 11 of the laminated busbar, the right end of the first copper-clad plate 11 is connected to the collector of the switch tube Q1, the emitter of the switch tube Q1 is connected to the collector of the switch tube Q2, the emitter of the switch tube Q2 is connected to the right end of the second copper-clad plate 12, and the second copper-clad plate 12 is connected to the collector of the switch tube Q1. The left end is connected to the negative electrode of the support capacitor C; the switch tube Q1 and the switch tube Q2 form a half-bridge structure, the fast recovery diode D1 is anti-parallel connected at both ends of the switch tube Q1, and the fast recovery diode D2 is anti-parallel connected at both ends of the switch tube Q2; after the first switch K1 and the second switch K2 are connected in series, the non-series end of the first switch K1 is connected to the common connection point of the solid-state switch KT and the first copper-clad board 11, and the non-series end of the second switch K2 is connected to the common connection point of the support capacitor C and the second copper-clad board 12, one end of the inductive load L is connected to the midpoint of the half-bridge structure, and the other end of the inductive load L is connected to the common connection point of the series connection of the first switch K1 and the second switch K2.

[0060] Figure 12This is a double pulse waveform diagram of a double pulse test. The working principle of the double pulse test system is as follows: disconnect the first switch K1 and close the second switch K2 to test the switch tube Q1 and the fast recovery diode D2; apply a double pulse waveform to the gate of the switch tube Q1. During the time period t1, the switch tube Q1 is turned on, and the current path is: the positive electrode of the supporting capacitor C → solid-state switch KT → the first copper-clad plate 11 of the laminated busbar → the switch tube Q1 → the inductive load L → the second switch K2 → the negative electrode of the supporting capacitor C. At this time, the first flexible coil current sensor 15 installed on the first copper-clad plate 11 of the laminated busbar collects the current. The current signal of the current path; in the time period t2, the switch tube Q1 is turned off, and the fast recovery diode D2 is freewheeling. The current path is: the right end of the inductive load L → the second switch K2 → the second copper clad board 12 of the laminated busbar → the fast recovery diode D2 → the left end of the inductive load L. At this time, the second flexible coil current sensor 16 installed on the second copper clad board 12 of the laminated busbar collects the current signal of the current path; in the time period t3, the switch tube Q1 is turned on, and a reverse voltage is applied to the fast recovery diode D2, causing it to turn off quickly. The current path in the time period t3 is the same as that in the time period t1.

[0061] The process of closing the first switch K1 and opening the second switch K2 to test the switch tube Q2 and the fast recovery diode D1 is similar to the process of testing the switch tube Q1 and the fast recovery diode D2, and will not be repeated here.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A circuit-symmetrical switching device double-pulse test laminated busbar, characterized in that: include: A first copper-clad plate (11), a second copper-clad plate (12), a first connecting component (13), a second connecting component (14), a first flexible coil current sensor (15), and a second flexible coil current sensor (16) are covered on the upper and lower surfaces of the dielectric substrate (10); a first insulating groove and a second insulating groove for horizontally mounting the first flexible coil current sensor (15) and the second flexible coil current sensor (16) are respectively provided on the first copper-clad plate (11) and the second copper-clad plate (12); the first insulating groove divides the first copper-clad plate (11) into two parts, the first connecting component (13) crosses the first flexible coil current sensor (15) to connect the two parts of the first copper-clad plate (11) divided by the first insulating groove, the second insulating groove divides the second copper-clad plate (12) into two parts, and the second connecting component (14) crosses the second flexible coil current sensor (16) to connect the two parts of the second copper-clad plate (12) divided by the second insulating groove.

2. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 1, wherein the projections of the first insulation groove and the second insulation groove perpendicular to the paper surface overlap.

3. According to the loop-symmetrical switching device double-pulse test laminated busbar of claim 2, the projections of the first flexible coil current sensor (15) and the second flexible coil current sensor (16) perpendicular to the paper surface overlap.

4. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 1, wherein the first insulating slot comprises: A first arc-shaped insulating installation groove (110), a first upper insulating gap (111) and a first lower insulating gap (112); the first upper insulating gap (111), the first arc-shaped insulating installation groove (110) and the first lower insulating gap (112) are connected end to end in sequence, dividing the first copper-clad plate (11) into a first protruding block (113) and a first recessed block (114); the second insulating groove comprises: a second arc-shaped insulating installation groove (120), a second upper insulating gap (121) and a second lower insulating gap (122); the second upper insulating gap (121), the second arc-shaped insulating installation groove (120) and the second lower insulating gap (122) are connected end to end in sequence, dividing the second copper-clad plate (12) into a second protruding block (123) and a second recessed block (124).

5. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 1, characterized in that: The first flexible coil current sensor (15) and the second flexible coil current sensor (16) both adopt Rogowski coils.

6. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 1, characterized in that: The dielectric substrate (10) is a PCB board.

7. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 4, characterized in that: The first connecting assembly (13) and the second connecting assembly (14) both use a plurality of parallel welding pins, and the plurality of parallel welding pins form an arc-shaped welding pin row.

8. A double pulse test system for a switching device using the laminated busbar according to any one of claims 1 to 7, characterized in that: include: A support capacitor C, a solid-state switch KT, a first switch K1, and a second switch K2; the positive electrode of the support capacitor C is connected to one end of the solid-state switch KT, the other end of the solid-state switch KT is connected to the first copper-clad plate (11) of the laminated busbar, and the negative electrode of the support capacitor C is connected to the second copper-clad plate (12); after the first switch K1 and the second switch K2 are connected in series, the non-series end of the first switch K1 is connected to the common connection point between the solid-state switch KT and the first copper-clad plate (11), and the non-series end of the second switch K2 is connected to the common connection point between the support capacitor C and the second copper-clad plate (12).

9. The double pulse test system for switching devices according to claim 8, characterized in that: Also includes: A switch tube Q1, a switch tube Q2, and an inductive load L; the switch tube Q1 and the switch tube Q2 form a half-bridge structure, the collector of the switch tube Q1 is connected to the first copper-clad plate (11), and the emitter of the switch tube Q2 is connected to the second copper-clad plate (12); one end of the inductive load L is connected to the midpoint of the half-bridge structure, and the other end of the inductive load L is connected to the series common point of the first switch K1 and the second switch K2.

10. The double pulse test system for switching devices according to claim 9, characterized in that: The method for testing the switch tube Q1 and the fast recovery diode D2 is as follows: (1) Open the first switch K1 and close the second switch K2, and apply a double pulse waveform to the gate of the switch tube Q1; (2) During the time period t1, the switch tube Q1 is turned on, and the current path is: the positive electrode of the supporting capacitor C → the solid-state switch KT → the first copper-clad plate 11 of the laminated busbar → the switch tube Q1 → the inductive load L → the second switch K2 → the negative electrode of the supporting capacitor C. At this time, the first flexible coil current sensor 15 installed on the first copper-clad plate 11 of the laminated busbar collects the current signal of the current path; (3) During the time period t2, the switch tube Q1 is turned off, and the fast recovery diode D2 is freewheeling. The current path is: the right end of the inductive load L → the second switch K2 → the second copper clad plate 12 of the laminated busbar → the fast recovery diode D2 → the left end of the inductive load L. At this time, the second flexible coil current sensor 16 installed on the second copper clad plate 12 of the laminated busbar collects the current signal of the current path; (4) During the t3 period, the switch tube Q1 is turned on, and a reverse voltage is applied to the fast recovery diode D2, causing it to turn off. The current path during the t3 period is the same as that during the t1 period.

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