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 field of switching device testing technology, solves the problem of how to reduce the stray inductance of the laminated busbar; on the upper and lower surfaces of the main circuit busbar, the path of the equivalent current forms a vertically symmetrical loop, 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, so the stray inductance introduced by the loop can be equivalent to zero, minimizing the current residual loop, greatly reducing the stray inductance of the loop, and meeting the double-pulse test requirements of SiC-based switching devices; two branch busbars are designed, and current sensors are installed on the branch busbars. Different types of current sensors can be installed, and the applicability is strong; at the same time, the width of the current path in the loop is the width of the branch busbar, and the width of the current path is no longer limited by the diameter of the current sensor, and the stray inductance in the loop is further reduced.

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 can evaluate not only the switching characteristics of the target device, 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 11 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 based on a set of external parameter tests. The external parameters in actual 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, L s 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 L as much as possible. s 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 circuit-symmetrical switching device double-pulse test laminated busbar comprises: a main circuit busbar (10) and two branch busbars; the main circuit busbar (10) comprises: a dielectric substrate and two copper-clad plates covering two surfaces of the dielectric substrate, each copper-clad plate is provided with an insulating groove (102), and the insulating groove (102) divides each copper-clad plate into two parts; the two branch busbars are respectively vertically inserted into the insulating grooves (102) provided on the two copper-clad plates of the main circuit busbar (10) and fixedly connected; each branch busbar is provided with a dielectric substrate and two copper-clad plates covering two surfaces of the dielectric substrate, each copper-clad plate is provided with an insulating groove (102), and the insulating groove (102) divides each copper-clad plate into two parts; The busbar includes: a dielectric substrate, a first copper-clad plate and a second copper-clad plate covered on both surfaces of the dielectric substrate, a current sensor, and a jumper assembly; a current sensor mounting groove is opened on the first copper-clad plate of the branch busbar, and the current sensor mounting groove divides the copper-clad plate into an outer copper block and an inner copper block. The inner copper block is conductively connected to the second copper-clad plate of the branch busbar; the current sensor is installed in the current sensor mounting groove parallel to the dielectric substrate of the branch busbar; the jumper assembly connects the outer copper block and the inner copper block across the current sensor.

[0015] When the laminated busbar of the present invention is used for double-pulse testing of SiC-based switching devices, the paths of equivalent currents form a symmetrical loop on the upper and lower surfaces of the main circuit busbar (10), the currents in the loop are equal in magnitude and opposite in direction, and according to the right-hand rule, the magnetic fields generated in the loop cancel each other out, so that the stray inductance introduced by the loop can be equivalent to zero, thereby minimizing the current residual loop and greatly reducing the stray inductance of the loop, thereby meeting the double-pulse testing requirements of SiC-based switching devices; two branch busbars are designed, and current sensors are installed on the branch busbars, and different types of current sensors can be installed, thus having strong applicability; at the same time, the width of the current path in the loop is the width of the branch busbar, and the width of the current path is no longer limited by the diameter of the current sensor, and the stray inductance in the loop is further reduced.

[0016] Furthermore, the projections of the insulation slots (102) provided on the two copper-clad plates of the main circuit busbar (10) in the xy plane overlap.

[0017] Furthermore, the projections of the current sensor mounting grooves provided on the first copper clad plates of the two branch busbars in the xy plane overlap.

[0018] In one embodiment, the current sensor is a Rogowski coil, a current transformer, or a coaxial resistor.

[0019] Furthermore, the circuit-symmetrical switching device double-pulse test laminated busbar further comprises: a connector assembly (13), wherein the connector assembly (13) comprises: a first L-shaped connector (131), a second L-shaped connector (132), a third L-shaped connector (133), and a fourth L-shaped connector (134); the first L-shaped connector (131), the second L-shaped connector (132), the third L-shaped connector (133), and the fourth L-shaped connector (134) are respectively welded to four intersections formed by the main circuit busbar (10) and the two branch busbars.

[0020] In one embodiment, the jumper assembly uses multiple parallel welding pins, which form an arc-shaped welding pin row. One end of the arc-shaped welding pin row is welded to the outer copper block, and the other end is welded to the inner copper block across the current sensor.

[0021] In one embodiment, the dielectric substrate is a PCB board.

[0022] A double-pulse test system for a switch device using the laminated busbar comprises: 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 one end of the upper surface of a main circuit busbar (10), and the negative electrode of the support capacitor C is connected to one end of the lower surface of the main circuit busbar (10); 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 main circuit busbar (10), and the non-series end of the second switch K2 is connected to the common connection point between the support capacitor C and the main circuit busbar (10).

[0023] Furthermore, the double-pulse test system for the switching device of the laminated busbar further comprises: 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 other end of the upper surface of the main circuit busbar (10), and the emitter of the switch tube Q2 is connected to the other end of the lower surface of the main circuit busbar (10); 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] Furthermore, 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 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 current sensor installed in the branch busbar above the laminated busbar collects the current signal of the current path;

[0027] (3) During the time period t2, the switch Q1 is turned off, and the fast recovery diode D2 continues to flow. The current path is: the right end of the inductive load L → the second switch K2 → the laminated busbar → the fast recovery diode D2 → the left end of the inductive load L. At this time, the current sensor installed in the branch busbar below the laminated busbar collects the current signal of the current path;

[0028] (4) During the t3 period, the switch tube Q1 is turned on, applying a reverse voltage 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 performing a double-pulse test on a SiC-based switching device, the path of the equivalent current forms a symmetrical loop on the upper and lower surfaces of the main circuit busbar (10). 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, thereby minimizing the current residual loop and greatly reducing the stray inductance of the loop, thus meeting the double-pulse test requirements of the SiC-based switching device.

[0031] (2) Two branch busbars are designed, and the current sensor is installed on the branch busbar. Different types of current sensors can be installed, which has strong applicability. At the same time, the width of the current path in the loop is the width of the branch busbar. The width of the current path is no longer limited by the diameter of the current sensor, and the stray inductance in the loop is further reduced.

[0032] (3) 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 outer copper block (inner copper block) through the arc-shaped welding pin row into the inner copper block (outer copper 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a front view of the structure of a laminated busbar using a flexible coil according to the first embodiment of the present invention;

[0034] Figure 2 The laminated busbar using flexible coils according to the first embodiment of the present invention is Figure 1 Side view in the negative direction of the y-axis;

[0035] Figure 3 This is a front view of a horizontal busbar of a laminated busbar using flexible coils according to the first embodiment of the present invention;

[0036] Figure 4 1 is a schematic diagram of the installation of flexible coils on the front surfaces of the first branch busbar and the second branch busbar of the laminated busbar using flexible coils according to the first embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the flexible coil current sensor mounting slots on the front surfaces of the first branch busbar and the second branch busbar of the laminated busbar using flexible coils according to the first embodiment of the present invention;

[0038] Figure 6 The connector assembly of the laminated busbar using the flexible coil according to the first embodiment of the present invention is arranged along Figure 1 Side view in the negative direction of the y-axis;

[0039] Figure 7 Schematic diagram of a symmetrical current equivalent circuit of a laminated busbar using a flexible coil according to the first embodiment of the present invention;

[0040] Figure 8 This is a structural front view of a laminated busbar using a current transformer according to a second embodiment of the present invention;

[0041] Figure 9 This is a front view of the structure of a laminated busbar using coaxial resistors according to a third embodiment of the present invention;

[0042] Figure 10 1 is a schematic structural diagram of a double-pulse test system for a switching device according to a fourth embodiment of the present invention;

[0043] Figure 11 This is a double pulse waveform diagram of a double pulse test of a switching device according to the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0044] 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.

[0045] The technical solution of the present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0046] Example 1

[0047] like Figure 1and Figure 2 As shown, a circuit symmetrical switching device double pulse test laminated busbar includes: a main circuit busbar 10, a first branch busbar 11, a second branch busbar 12, and a connector assembly 13; Figure 3 As shown, the main circuit busbar 10 includes: a first dielectric substrate 101 and two copper-clad plates covering the upper and lower surfaces of the first dielectric substrate 101. Each copper-clad plate is provided with an insulation slot 102, which divides each copper-clad plate into two non-conductive parts. The first branch busbar 11 is perpendicular to the main circuit busbar 10 and inserted into the insulation slot 102 on the copper-clad plate on the upper surface of the first dielectric substrate 101. The second branch busbar 12 is perpendicular to the main circuit busbar 10 and inserted into the insulation slot 102 on the copper-clad plate on the lower surface of the first dielectric substrate 101. The first branch busbar 11, the second branch busbar 12, and the main circuit busbar 10 are fixed using a connector assembly 13.

[0048] Such as 4 and Figure 5 As shown, the first branch busbar 11 includes: a second dielectric substrate 110 and two copper-clad laminates covering the front and rear surfaces of the second dielectric substrate 110, a first flexible coil current sensor 114, and a first jumper assembly 115. A first flexible coil current sensor mounting slot 112 is defined on the copper-clad laminate on the front surface of the second dielectric substrate 110. The first flexible coil current sensor mounting slot 112 divides the copper-clad laminate on the front surface of the second dielectric substrate 110 into a first outer copper block 111 and a first inner copper block 113. The first outer copper block 111 and the first inner copper block 113 are electrically non-conductive, while the first inner copper block 113 is electrically conductively connected to the copper-clad laminate on the rear surface of the second dielectric substrate 110. The first flexible coil current sensor mounting slot 112 is used to mount the first flexible coil current sensor 114 parallel to the second dielectric substrate 110. The first jumper assembly 115 spans the first flexible coil current sensor 114 and connects the first outer copper block 111 and the first inner copper block 113.

[0049] Such as 4 and Figure 5As shown, the second branch busbar 12 includes: a third dielectric substrate 120 and two copper-clad laminates covering the front and rear surfaces of the third dielectric substrate 120, a second flexible coil current sensor 124, and a second jumper assembly 125. A second flexible coil current sensor mounting slot 122 is defined in the copper-clad laminate on the front surface of the third dielectric substrate 120. The second flexible coil current sensor mounting slot 122 divides the copper-clad laminate on the front surface of the third dielectric substrate 120 into a second outer copper block 121 and a second inner copper block 123. The second outer copper block 121 and the second inner copper block 123 are electrically non-conductive, while the second inner copper block 123 is electrically conductively connected to the copper-clad laminate on the rear surface of the third dielectric substrate 120. The second flexible coil current sensor mounting slot 122 is used to mount the second flexible coil current sensor 124 parallel to the third dielectric substrate 120. The second jumper assembly 125 spans the second flexible coil current sensor 124 and connects the second outer copper block 121 and the second inner copper block 123.

[0050] The first flexible coil current sensor 114 and the second flexible coil current sensor 124 both use Rogowski coils.

[0051] The first jumper assembly 115 and the second jumper assembly 125 both use multiple parallel welding pins, which cross the flexible coil current sensor. One end of the welding pin is welded to the outer copper block, and the other end of the welding pin is welded to the inner copper block. The multiple parallel welding pins form 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 outer copper block through the arc-shaped welding pin row into the inner copper 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.

[0052] like Figure 1 、 Figure 2 、 Figure 6As shown, the connector assembly 13 includes: a first L-shaped connector 131, a second L-shaped connector 132, a third L-shaped connector 133, and a fourth L-shaped connector 134; the horizontal surface of the first L-shaped connector 131 is welded to the copper-clad plate on the upper surface of the first dielectric substrate 101, and the vertical surface of the first L-shaped connector 131 is welded to the first outer copper-clad block 111 on the front surface of the first branch busbar 11; the horizontal surface of the second L-shaped connector 132 is welded to the copper-clad plate on the upper surface of the first dielectric substrate 101, and the vertical surface of the second L-shaped connector 133 is welded to the first outer copper-clad block 111 on the front surface of the first branch busbar 11; The vertical surface of the connector 132 is welded to the copper clad block on the rear surface of the first branch busbar 11; the horizontal surface of the third L-shaped connector 133 is welded to the copper clad plate on the lower surface of the first dielectric substrate 101, and the vertical surface of the third L-shaped connector 133 is welded to the second outer copper clad block 121 on the front surface of the second branch busbar 12; the horizontal surface of the fourth L-shaped connector 134 is welded to the copper clad plate on the lower surface of the first dielectric substrate 101, and the vertical surface of the fourth L-shaped connector 134 is welded to the copper clad block on the rear surface of the second branch busbar 12.

[0053] Working principle of laminated busbar:

[0054] like Figures 1 to 6 As shown, when performing a double pulse test on a SiC-based switching device, on the upper surface of the main circuit busbar 10, the current of the test circuit flows from the copper-clad plate on the left side of the upper surface of the first dielectric substrate 101, passes through the first L-shaped connector 131, flows upward into the first outer copper-clad block 111 on the front surface of the first branch busbar 11, then flows through the first jumper component 115 into the first inner copper-clad block 113, then flows from the first inner copper-clad block 113 to the copper-clad block on the rear surface of the first branch busbar 11, then flows downward from the copper-clad block on the rear surface of the first branch busbar 11 into the second L-shaped connector 132, and then flows from the second L-shaped connector 132 into the copper-clad plate on the right side of the upper surface of the first dielectric substrate 101; wherein, the current flows from the first outer copper-clad block 111 through the first jumper component 115 into the first inner copper-clad block 113, thereby passing through the first flexible coil current sensor 1 14 completes current detection; on the upper surface of the main circuit busbar 10, the current of the test circuit flows from the copper-clad plate on the right side of the lower surface of the first dielectric substrate 101, passes through the fourth L-shaped connector 134, and flows downward into the copper-clad block on the rear surface of the second branch busbar 12. Then, it flows from the copper-clad block on the rear surface of the second branch busbar 12 into the second inner copper-clad block 123, and then from the second inner copper-clad block 123 into the second outer copper-clad block 121 through the second jumper component 125. Then, the second outer copper-clad block 121 flows upward into the third L-shaped connector 133, and then from the third L-shaped connector 133 into the copper-clad plate on the left side of the lower surface of the first dielectric substrate 101. Among them, the current flows from the second inner copper-clad block 123 through the second jumper component 125 into the second outer copper-clad block 121, thereby passing through the second flexible coil current sensor 124 to complete current detection.

[0055] like Figure 7 As shown, when performing a double-pulse test on a SiC-based switching device, the path of the equivalent current forms a vertically symmetrical loop on the upper and lower surfaces of the main circuit busbar 10. 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.

[0056] Example 2

[0057] like Figure 8 As shown, the laminated busbar of this embodiment differs from that of the first embodiment in that the first flexible coil current sensor 114 and the second flexible coil current sensor 124 in the first embodiment are replaced by current transformers, and current transformer mounting grooves are provided on the copper-clad plates on the front surfaces of the second dielectric substrate 110 and the third dielectric substrate 120 for mounting the current transformers.

[0058] Example 3

[0059] like Figure 9 As shown, the difference between the laminated busbar of this embodiment and that of the first embodiment is that the first flexible coil current sensor 114 and the second flexible coil current sensor 124 in the first embodiment are replaced by coaxial resistors, and coaxial resistor mounting grooves are provided on the copper clad plates on the front surfaces of the second dielectric substrate 110 and the third dielectric substrate 120 for mounting the coaxial resistors.

[0060] Example 4

[0061] like Figure 10 As shown, a double-pulse test system for a switching device includes: a support capacitor C, a solid-state switch KT, a laminated busbar, a switching tube Q1, a switching 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 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 upper left end of the laminated busbar, the upper right end of the laminated busbar is connected to the collector of the switching tube Q1, the emitter of the switching tube Q1 is connected to the collector of the switching tube Q2, the emitter of the switching tube Q2 is connected to the lower right end of the laminated busbar, and the lower left end of the laminated busbar is connected to the negative electrode of the support capacitor C;

[0062] 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 upper part of the laminated busbar, and the non-series end of the second switch K2 is connected to the common connection point of the support capacitor C and the lower part of the laminated busbar. 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.

[0063] Figure 11 This is a double pulse waveform diagram of the 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. The current path is: the positive electrode of the support capacitor C → solid-state switch KT → the upper part of the laminated busbar → switch tube Q1 → inductive load L → second switch K2 → the negative electrode of the support capacitor C. At this time, the current sensor installed in the branch busbar on the upper part of the laminated busbar collects The current signal of the current path; during the t2 period, 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 lower part of the laminated busbar → the fast recovery diode D2 → the left end of the inductive load L. At this time, the current sensor installed in the branch busbar at the lower part of the laminated busbar collects the current signal of the current path; during the t3 period, the switch tube Q1 is turned on, applying a reverse voltage to the fast recovery diode D2, causing it to turn off quickly. The current path during the t3 period is the same as that during the t1 period.

[0064] 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.

[0065] 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: Main circuit busbar (10), two branch busbars; The main circuit busbar (10) comprises: a dielectric substrate and two copper-clad plates covered on both surfaces of the dielectric substrate, each copper-clad plate is provided with an insulating groove (102), and the insulating groove (102) divides each copper-clad plate into two parts; the two branch busbars are respectively vertically inserted into the insulating grooves (102) provided on the two copper-clad plates of the main circuit busbar (10) and fixedly connected; each branch busbar comprises: a dielectric substrate and a first copper-clad plate and a second copper-clad plate covered on both surfaces of the dielectric substrate, a current sensor, and a jumper assembly; a current sensor mounting groove is provided on the first copper-clad plate of the branch busbar, the current sensor mounting groove divides the copper-clad plate into an outer copper block and an inner copper block, the inner copper block is conductively connected to the second copper-clad plate of the branch busbar, the current sensor is mounted in the current sensor mounting groove parallel to the dielectric substrate of the branch busbar, and the jumper assembly crosses the current sensor to connect the outer copper block and the inner copper block.

2. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 1, characterized in that: The projections of the insulation slots (102) opened on the two copper-clad plates of the main circuit busbar (10) in the xy plane overlap.

3. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 2, characterized in that: The projections of the current sensor mounting grooves provided on the first copper-clad plates of the two branch busbars in the xy plane overlap.

4. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 1, characterized in that: The current sensor adopts a Rogowski coil, a current transformer or a coaxial resistor.

5. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 1, characterized in that: Also includes: A connector assembly (13), the connector assembly (13) comprising: a first L-shaped connector (131), a second L-shaped connector (132), a third L-shaped connector (133), and a fourth L-shaped connector (134); the first L-shaped connector (131), the second L-shaped connector (132), the third L-shaped connector (133), and the fourth L-shaped connector (134) are respectively welded to four intersections formed by a main circuit busbar (10) and two branch busbars.

6. The circuit-symmetrical switching device double-pulse test laminated busbar according to claim 1, characterized in that: The jumper assembly uses multiple parallel welding pins, which form an arc-shaped welding pin row. One end of the arc-shaped welding pin row is welded to the outer copper block, and the other end is welded to the inner copper block across the current sensor.

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

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 one end of the upper surface of the main circuit busbar (10), and the negative electrode of the support capacitor C is connected to one end of the lower surface of the main circuit busbar (10); 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 main circuit busbar (10), and the non-series end of the second switch K2 is connected to the common connection point between the support capacitor C and the main circuit busbar (10).

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 other end of the upper surface of the main circuit busbar (10), and the emitter of the switch tube Q2 is connected to the other end of the lower surface of the main circuit busbar (10); 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 point of the series connection 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 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 current sensor installed in the branch busbar above the laminated busbar collects the current signal of the current path; (3) During the time period t2, the switch Q1 is turned off, and the fast recovery diode D2 continues to flow. The current path is: the right end of the inductive load L → the second switch K2 → the laminated busbar → the fast recovery diode D2 → the left end of the inductive load L. At this time, the current sensor installed in the branch busbar below the laminated busbar collects the current signal of the current path; (4) During the t3 period, the switch tube Q1 is turned on, applying a reverse voltage 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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