A silicon carbide switching device test apparatus

Abstract

The application relates to a silicon carbide switch device testing device which comprises a connecting copper bar and a pressing rod; one end of the connecting copper bar is electrically connected with the terminal of a testing capacitor, the other end of the connecting copper bar is fixedly connected with the middle part of the pressing rod, and the one end of the connecting copper bar is a pressing end for pressing and electrically connecting the terminal of the silicon carbide switch device; the included angle between the plane where the connecting copper bar is located and the straight line where the pressing rod is located is within a set angle range, and the distance between the connecting copper bar and the terminal of the silicon carbide switch device is within a preset distance range, so that the stray inductance in the testing circuit is minimized, and the testing requirements of the silicon carbide switch device are met.

Description

Technical Field

[0001] This application relates to the field of testing silicon carbide switching devices, and in particular to a testing apparatus for silicon carbide switching devices. Background Technology

[0002] Silicon carbide (SiC) switching devices utilize a wide bandgap technology. Compared to classic silicon switching devices, SiC switching devices feature low on-state resistance and high thermal conductivity, which contribute to improved energy efficiency and operating temperature in end-use circuits. Therefore, the development technology of SiC switching devices has gradually advanced. During the design process of SiC switching devices, testing of the designed products is necessary, thus requiring the use of specialized testing platforms for SiC switching devices.

[0003] For silicon carbide (SiC) switching device testing platforms, the main circuit noisy inductance is a crucial performance indicator. The rapid rise and fall of current in SiC switching devices necessitates sufficiently low main circuit noisy inductance to ensure accurate testing across the entire measurement range. With increasing demands for testing efficiency, manufacturers require more automated testing platforms. Therefore, automated mechanical structures for housing SiC switching devices have been added to existing manually operated platforms. However, this additional automated mechanical structure, connected in series in the main circuit, increases the main circuit noisy inductance, causing a significant decrease in the testing performance of the automated testing platform.

[0004] Currently, the main circuit inductance of test platforms with added automation is generally 40nH, which is far below the requirements for testing silicon carbide switching devices. Therefore, there is a need for an automated test platform whose main circuit inductance meets the testing requirements for silicon carbide switching devices. Summary of the Invention

[0005] In order to automatically test silicon carbide switching devices while meeting the testing requirements for silicon carbide switching devices, this application provides a silicon carbide switching device testing apparatus.

[0006] The silicon carbide switching device testing apparatus provided in this application adopts the following technical solution:

[0007] A testing device for silicon carbide switching devices includes a copper busbar and a pressure bar.

[0008] One end of the connecting copper busbar is electrically connected to the terminal of the test capacitor, and the other end of the connecting copper busbar is fixedly connected to the middle part of the pressure rod. One end of the connecting copper busbar is a crimping end to crimp and electrically connect to the terminal of the silicon carbide switching device.

[0009] The angle between the plane where the connecting copper busbar is located and the straight line where the pressure rod is located is within a set angle range, and the distance between the connecting copper busbar and the terminal of the silicon carbide switching device is within a preset distance range.

[0010] By adopting the above technical solution, the connecting copper busbar is connected to the middle part of the pressure rod. Based on this, the attitude and position between the connecting copper busbar and the pressure rod will affect the spurious inductance in the test circuit. By adjusting the attitude relationship between the connecting copper busbar and the pressure rod to a set angle range and adjusting the position relationship between the connecting copper busbar and the pressure rod to a preset distance range, the spurious inductance in the test circuit can be minimized, thereby meeting the test requirements of silicon carbide switching devices.

[0011] Preferably, the portion of the connecting copper busbar that is fixedly connected to the pressure rod surrounds the pressure rod.

[0012] By adopting the above technical solution, the connecting copper busbar surrounds the pressure rod, which can disperse the charge accumulated at the connection point between the connecting copper busbar and the pressure rod, thus reducing unwanted inductance.

[0013] Preferably, the crimping end is provided with a crimping tip for crimping the terminals of the silicon carbide switching device.

[0014] By adopting the above technical solution, the pressing tip can apply higher pressure to the terminals of silicon carbide switching devices, resulting in a better crimping effect.

[0015] Preferably, the pressure rods are provided in multiple forms and connected to the same connecting copper busbar, and are electrically connected in parallel to each other.

[0016] By adopting the above technical solution, multiple pressure bars connected in parallel can more tightly press the terminals of silicon carbide switching devices, and also reduce the extra interference caused by setting pressure bars in the device.

[0017] Preferably, the plurality of pressure bars are arranged in parallel to each other.

[0018] By adopting the above technical solution, the parallel arrangement of the pressure bars can apply uniform pressure to the terminals of the silicon carbide switching device when the pressure bars are of the same length. At the same time, the structure of the contact between the pressure bar end and the terminal of the silicon carbide switching device is kept consistent, thereby making the distribution of stray inductance on multiple pressure bars more uniform, which is beneficial to improving the effect of parallel pressure bars in reducing stray inductance.

[0019] Preferably, a first insulating pressure plate is inserted into the pressure rod, the first insulating pressure plate has a first through hole, the pressure rod is interference-fitted into the first through hole, the first insulating pressure plate is located on the pressure rod between the connecting copper busbar and the crimping end, and the connecting copper busbar is crimped onto the first insulating pressure plate.

[0020] By adopting the above technical solution, the first insulating pressure plate can fix the relative position between the pressure rod and the connecting copper busbar. The use of a metal plate for the first insulating pressure plate can also alleviate the accumulation of sharp charges on the pressure rod and the connecting copper busbar, which helps to reduce unwanted inductance.

[0021] Preferably, the first insulating pressure plate is provided with a first receiving groove for accommodating the connecting copper busbar.

[0022] By adopting the above technical solution, the first receiving groove can surround at least two sides of the connecting copper busbar after accommodating the connecting copper busbar, which can fix the relative posture between the connecting copper busbar and the pressure rod, and facilitate the fixed connection between the connecting copper busbar and the pressure rod.

[0023] Preferably, the first insulating pressure plate is fitted with a second insulating pressure plate, the second insulating pressure plate has a second through hole, and the end of the pressure rod away from the crimping end is inserted into the second through hole. The second insulating pressure plate and the first insulating pressure plate clamp or tighten the connecting copper busbar in the middle.

[0024] By adopting the above technical solution, the first insulating plate and the second insulating plate can clamp the connecting copper busbar on the pressure rod after they are combined, and at the same time they can surround the connecting copper busbar, which is conducive to fixing the position of the connecting copper busbar on the pressure rod.

[0025] Preferably, the second insulating pressure plate is provided with a second receiving groove to accommodate the connecting copper busbar.

[0026] By adopting the above technical solution, the second receiving groove can surround at least two sides of the connecting copper busbar after accommodating the connecting copper busbar, which is beneficial to fixing the relative posture between the connecting copper busbar and the pressure rod.

[0027] Preferably, the connecting copper busbar is provided with multiple sections, and the first receiving groove and the second receiving groove are staggered.

[0028] By adopting the above technical solution, multiple connecting copper busbars can be connected to different terminals of the test capacitor, and a single device can be used to test multiple silicon carbide switching devices.

[0029] In summary, this application includes at least the following beneficial technical effects: using connecting copper busbars and pressure bars that conform to a set attitude and preset position relationship reduces the noise in the test circuit, thus meeting the testing requirements of silicon carbide switching devices. Utilizing a first insulating pressure plate with a first receiving groove and a second insulating pressure plate with a second receiving groove facilitates the shaping of the attitude and position between the connecting copper busbars and pressure bars, while also reducing noise in the test circuit, thereby making the test results of silicon carbide switching devices more accurate. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the silicon carbide switching device testing device;

[0031] Figure 2 It is an enlarged structural diagram showing the connecting copper busbar, pressure bar, and first insulating pressure plate;

[0032] Figure 3 yes Figure 1 A magnified structural diagram of part A in the diagram.

[0033] Reference numerals: 10, test capacitor; 11, first electrode; 12, second electrode; 20, automated fixture; 30, connecting copper busbar; 40, pressure rod; 41, crimping end; 50, first insulating pressure plate; 51, first through hole; 52, first receiving groove; 60, second insulating pressure plate; 61, second through hole; 62, second receiving groove. Detailed Implementation

[0034] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0035] In the prior art, the test circuit for silicon carbide switching devices includes a test capacitor 10, an automated fixture 20, and the silicon carbide switching device to be tested. The automated fixture 20 includes a first part and a second part, along with the test capacitor 10, the automated fixture 20, and the silicon carbide switching device to be tested. Traditional manual test circuits consist of the test capacitor 10 and the silicon carbide switching device to be tested. Existing automated test circuits consist of the test capacitor 10, the first part, the silicon carbide switching device to be tested, and the second part. Compared to manual test circuits, the first and second parts introduce more noise into the test circuit.

[0036] This application discloses a testing device for silicon carbide switching devices, which can reduce the unwanted inductance introduced by the automated fixture 20 into the test circuit. (Refer to...) Figure 1 and Figure 2 A silicon carbide switching device testing apparatus includes a connecting copper busbar 30, multiple pressure bars 40, a first insulating pressure plate 50, and a second insulating pressure plate 60. The test capacitor 10 has two sheet-like, staggered electrodes, a first electrode 11 and a second electrode 12, arranged parallel to each other. The connecting copper busbar 30 is bolted to the electrodes. A through hole is provided between the connecting copper busbar 30 and the electrodes; the bolt passes through the hole and secures the connecting copper busbar 30 to the electrodes, thus achieving electrical connection between them. In other embodiments, the connecting copper busbar 30 can be welded to the electrodes for both fixation and electrical connection.

[0037] The pressure rod 40 is welded to the end of the connecting copper busbar 30 furthest from the electrode, and the connecting copper busbar 30 is located in the middle of the pressure rod 40. Soldering can be used for welding. The welded portion of the connecting copper busbar 30 and the pressure rod 40 surrounds the pressure rod 40. The end of the connecting copper busbar 30 used to press the terminals of the silicon carbide switching device is a crimp end 41. The crimp end 41 has a crimping tip, which can be directly formed on the crimp end 41 or is a detachable or fixed assembly connected to the crimp end 41. The crimping tip is used to press the terminals of the silicon carbide switching device. The crimping tip can be a tapered body with a tapered end, a pointed body with multiple serrated tips, or a tubular body. The crimping tip provides higher pressure after pressing the terminals of the silicon carbide switching device, resulting in a tighter crimp.

[0038] Through simulation and actual testing, it was found that parallel arrangement of multiple pressure bars 40 connected in parallel to the same connecting copper busbar 30 improves the clamping effect of the pressure bars 40 on the terminals of silicon carbide switching devices and reduces stray inductance. In the tested case, the test circuit with multiple pressure bars 40 connected in parallel reduced stray inductance by 2nH compared to the test circuit with a single pressure bar 40. The stray inductance in the test circuit varies depending on the distance between the connecting copper busbar 30 and the crimping end 41. The farther the connecting copper busbar 30 is from the crimping end 41, the greater the stray inductance in its test circuit. In the tested case, increasing the distance between the connecting copper busbar 30 and the crimping end 41 by 14mm increased the stray inductance in the test circuit by 8nH. The distance between the connecting copper busbar 30 and the crimping end 41 can be 0~14mm or even greater. Simulation and actual testing also showed that the stray inductance in the test circuit varies depending on the orientation of the connecting copper busbar 30 and the crimping end 41. The closer the orientation of the connecting copper busbar 30 and the crimp terminal 41 is to being perpendicular, the lower the stray inductance in the test circuit. The closer the two connecting copper busbars 30 or the two electrodes of the test capacitor are to each other, the lower the stray inductance in the test circuit.

[0039] like Figure 2 and Figure 3 As shown, the first insulating pressure plate 50 and the second insulating pressure plate 60 are configured to cooperate with each other. The first insulating pressure plate 50 has multiple first through holes 51 through which the pressure rods 40 pass, and the pressure rods 40 are interference-fitted into the first through holes 51. The second insulating pressure plate 60 has second through holes 61 through which the pressure rods 40 pass. The positions of the first through holes 51 and the second through holes 61 correspond, and the first through holes 51 and the second through holes 61 corresponding to the position through which the same pressure rod 40 passes. The second insulating pressure plate 60 is fixedly connected to the automated fixture 20 by adhesive, hot melt welding, or bolts. The first insulating pressure plate 50 can also be fixedly connected to the second insulating pressure plate 60 by adhesive, hot melt welding, or bolts.

[0040] The assembly process of the first insulating pressure plate 50 and the second insulating pressure plate 60 is as follows: The end of the pressure rod 40 away from the crimping end 41 passes through the first through hole 51, allowing the pressure rod 40 to be interference-fitted onto the first insulating pressure plate 50. The connecting copper busbar 30 has a hole for the pressure rod 40 to pass through. The connecting copper busbar 30 is inserted onto the pressure rod 40 from the end away from the crimping end 41. The first insulating pressure plate 50 has a first receiving groove 52 for accommodating the connecting copper busbar 30. The opening of the first receiving groove 52 faces away from the crimping end 41. The connecting copper busbar 30 is pressed into the first receiving groove 52. The connecting copper busbar 30 and the pressure rod 40 are soldered together on the side of the connecting copper busbar 30 away from the first insulating pressure plate 50. The pressure rod 40 connected to the first electrode 11 passes through the first receiving groove 52, while the pressure rod 40 connected to the second electrode 12 does not pass through the first receiving groove 52. The connecting copper busbar 30 connected to the pressure rod 40 that does not pass through the first receiving groove 52 is attached to the surface of the first insulating pressure plate 50. The second insulating pressure plate 60 is inserted into the pressure rod 40 from the end away from the crimping end 41 and presses against the connecting copper busbar 30. The second insulating pressure plate 60 is provided with a second receiving groove 62, the position of which corresponds to and accommodates the connecting copper busbar 30 connected to the second electrode 12. There are multiple connecting copper busbars 30 on the automated fixture 20. At the same time, the positions of the first receiving groove 52 and the second receiving groove 62 can correspond or be offset. The second receiving groove 62 can also be located within the first receiving groove 52, surrounding the connecting copper busbar 30, or the first receiving groove 52 can also be located within the second receiving groove 62, surrounding the connecting copper busbar 30. Finally, the relative positions between the first insulating pressure plate 50 and the second insulating pressure plate 60 are fixed.

[0041] The implementation principle of the silicon carbide switching device testing device in this application embodiment is as follows: The pressure bars 40 are connected in parallel and arranged parallel to each other, making the stray inductance distribution on the multiple pressure bars 40 more uniform, which is beneficial to reducing the total stray inductance of the test circuit. The connecting copper busbar 30 surrounds the pressure bars 40, and the welding path also surrounds the pressure bars 40, which can disperse the charge accumulated at the connection point between the connecting copper busbar 30 and the pressure bars 40, alleviating the degree of charge accumulation at the tip of the connection point between the pressure bars 40 and the connecting copper busbar 30, thus helping to reduce the total stray inductance of the test circuit. Using connecting copper busbar 30 and pressure bars 40 that conform to the set posture relationship and preset position relationship reduces the stray inductance of the test circuit to meet the testing requirements of silicon carbide switching devices. After the first insulating pressure plate 50 and the second insulating pressure plate 60 press the connecting copper busbar 30 together, it not only helps to maintain the posture and position relationship between the connecting copper busbar 30 and the pressure bars 40, but also improves the effect of alleviating the degree of charge accumulation at the tip of the pressure bars 40 and the connecting copper busbar 30, thereby making the test results of the silicon carbide switching devices more accurate.

[0042] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A silicon carbide switching device test apparatus, characterized by: Including connecting the copper busbar (30) and the pressure bar (40); One end of the connecting copper busbar (30) is electrically connected to the terminal of the test capacitor (10), and the other end of the connecting copper busbar (30) is fixedly connected to the middle part of the pressure rod (40). One end of the pressure rod (40) is a crimping end (41) to crimp and electrically connect to the terminal of the silicon carbide switching device. The crimping end (41) is provided with a crimping tip, which is formed on the crimping end (41), or the crimping tip is configured as an assembly that is detachably connected and fixedly connected to the crimping end (41); The angle between the plane of the connecting copper busbar (30) and the straight line of the pressure rod (40) is within a set angle range, and the distance between the connecting copper busbar (30) and the crimping end (41) of the pressure rod (40) is within a preset distance range; A first insulating pressure plate (50) is inserted into the pressure rod (40). The first insulating pressure plate (50) has a first through hole (51). The pressure rod (40) is interference-fitted into the first through hole (51). The first insulating pressure plate (50) is located on the pressure rod (40) between the connecting copper busbar (30) and the crimping end (41). The connecting copper busbar (30) is crimped onto the first insulating pressure plate (50). The first insulating pressure plate (50) has a first receiving groove (52) for accommodating the connecting copper busbar (30). The first insulating pressure plate (50) is fitted with a second insulating pressure plate (60). The second insulating pressure plate (60) has a second through hole (61). The end of the pressure rod (40) away from the crimping end (41) is inserted into the second through hole (61). The second insulating pressure plate (60) and the first insulating pressure plate (50) clamp the connecting copper busbar (30) in the middle and tighten it. The second insulating pressure plate (60) has a second receiving groove (62) for accommodating the connecting copper busbar (30). Multiple pressure rods (40) are provided and connected to the same connecting copper busbar (30), and are electrically connected in parallel to each other; multiple pressure rods (40) are arranged in parallel to each other; multiple connecting copper busbars (30) are provided, and the first receiving groove (52) and the second receiving groove (62) are staggered.

2. The silicon carbide switching device testing device according to claim 1, characterized in that: The portion where the connecting copper busbar (30) is fixedly connected to the pressure rod (40) surrounds the pressure rod (40).

3. The silicon carbide switching device testing device according to claim 1, characterized in that: The crimping end (41) is provided with a crimping tip for crimping the terminals of the silicon carbide switching device.

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