A DC support capacitor impulse discharge test device

Abstract

The present invention relates to the technical field of power electronic capacitor testing, and specifically to a DC support capacitor impulse discharge testing device. It includes a first and a second wiring board arranged in parallel, a discharge gap installed on the first and the second wiring board, and a discharge trigger device. The discharge gap includes a first and a second discharge block, and two conductive inclined surfaces and two inner side surfaces of the first and the second discharge blocks form a bottomless Y-shaped groove. The discharge trigger device includes a fixed plate, a movable plate and a conductive cylinder. In the initial state of the test, the conductive cylinder is supported by the movable plate and stays in the long through hole. During the test, the first and the second wiring boards are inserted into the installation through hole through the terminal posts and fixed on the top of the DC support capacitor. The device has the technical effects of large peak discharge current, small impedance, safe trigger discharge mode, simple manufacturing process, low cost and reliable operation.

Description

Technical Field

[0001] The invention relates to the technical field of power electronic capacitor testing, in particular to a direct current support capacitor impulse discharge testing device. Background Art

[0002] With the development of power electronic IGBT converter technology, the safety performance requirements for key components such as DC support capacitors are becoming increasingly higher. The two electrodes of the DC support capacitor are connected to a number of spaced terminals, and the terminals of the two electrodes form two parallel columns and are arranged at the top of the capacitor. DC support capacitors have the characteristics of large capacity, high design field strength, large current resistance, low impedance, low inductance, and high stability. They are widely used in flexible DC transmission, photovoltaic inverters, high-voltage inverters, electric locomotives and other fields. Due to the high standards for safety performance, especially the non-repetitive peak discharge current generated under system switching or module failure conditions is very large, the DC support capacitor (hereinafter referred to as: capacitor) impulse discharge test is specified in the relevant standards to verify its reliability. The test requires that the two poles of the capacitor be directly short-circuited and discharged under DC voltage, thereby generating an oscillating discharge current with a specified maximum peak current. The type test stipulates that each capacitor is discharged 5 times in this way, but no specific test implementation method is given. The maximum peak current specified in the corresponding technical specifications is very large, usually reaching hundreds of kiloamperes, or even requiring a megaampere level. This requires that the circuit impedance of the discharge device itself is very small, and at the same time, the vibration force and high temperature generated by such a huge impact current must be considered, which puts extremely stringent requirements on the triggering method, materials and structure of the discharge device. At present, the commonly used copper plate short circuit or mechanical discharge switch method cannot meet the test requirements. Summary of the invention

[0003] The invention aims to provide a DC support capacitor impulse discharge test device with large peak discharge current, small impedance, safe trigger discharge mode, simple manufacturing process and low cost.

[0004] The technical solution to achieve the above-mentioned purpose includes the following contents.

[0005] A DC support capacitor impulse discharge test device comprises a first and a second wiring board arranged in parallel, a discharge gap installed on the first and the second wiring board, and a discharge trigger device.

[0006] The first and second wiring boards are provided with a plurality of mounting through holes at intervals along their length direction, the size of the mounting through holes matches the outer diameter of the terminal posts on the DC support capacitor, and the spacing between the mounting through holes is consistent with the spacing between the terminal posts on the DC support capacitor.

[0007] The discharge gap comprises a first discharge block and a second discharge block. The bottoms of the first discharge block and the second discharge block are respectively mounted on the middle of the first and second wiring boards. The adjacent parts of the tops of the first and second discharge blocks are each provided with a conductive inclined surface. The two conductive inclined surfaces and the two inner side surfaces of the first and second discharge blocks form a bottomless Y-shaped groove.

[0008] The discharge trigger device comprises a fixed plate, a movable plate and a conductive cylinder. The fixed plate is horizontally arranged and fixed above the discharge block. A long through hole is arranged in the center of the fixed plate. The length direction of the long through hole is parallel to the length direction of the Y-shaped groove, and the long through hole is located directly above the Y-shaped groove. The movable plate can slide and is horizontally arranged between the fixed plate and the discharge block. The diameter and length of the conductive cylinder are adapted to the width and length of the long through hole. In the initial state of the test, the conductive cylinder is supported by the movable plate and stays in the long through hole.

[0009] During the test, the first and second terminal blocks were inserted into the mounting through holes through the terminal posts and fixed on the top of the DC support capacitor. The current started from one electrode of the DC support capacitor, passed through the terminal post, the first terminal block, the first discharge block, the conductive inclined plane, the conductive cylinder, the conductive inclined plane, the second discharge block, the second terminal block, the terminal post, and returned to the other electrode of the DC support capacitor.

[0010] Furthermore, a bayonet for mounting a current sensor is provided at the bottom of the first discharge block or the second discharge block.

[0011] Furthermore, the mounting through holes on the first wiring board and / or the second wiring board are strip-shaped through holes, and the length direction of the strip-shaped through holes is perpendicular to the arrangement direction of the terminals on the DC support capacitor. The strip-shaped through holes are arranged to facilitate adjusting the distance between the two wiring boards to adapt to different discharge voltages.

[0012] Furthermore, the fixed plate is fixed to the top of the discharge block by bolts, and a groove matching the size of the movable plate is provided at the bottom of the fixed plate. The movable plate is supported by the first and second discharge blocks and stays in the groove.

[0013] Furthermore, the conductive cylinder and the first and second discharge blocks are made of tungsten copper.

[0014] When the above-mentioned DC support capacitor impulse discharge test device is used, firstly, two terminal boards are respectively installed on the terminal posts on the two electrodes of the capacitor so that the two terminal boards are parallel and parallel, and then the distance between the two terminal boards can be adjusted according to the discharge voltage, and then the discharge trigger device is installed. When the capacitor is charged to the test voltage required for the test, the movable plate is pulled out from under the fixed plate through remote control, and the conductive cylinder falls from the long through hole into the Y-shaped groove, and the conductive cylinder connects the two conductive inclined surfaces to achieve discharge.

[0015] The beneficial effects of the present invention are:

[0016] The discharge gap is installed in the middle of the parallel wiring board, the two conductive inclined surfaces are symmetrically arranged, and the conductive cylinder is in contact with the two conductive inclined surfaces, which greatly reduces the impedance of the discharge device itself and greatly improves the discharge current peak value, ensuring that the discharge device can withstand impact vibration force and has high reliability; the discharge trigger device is arranged at the top of the discharge block, which is convenient for the discharge energy to diverge upward and protect the capacitor housing and the current sensor from arc erosion; the movable plate is pulled out from under the fixed plate to achieve circuit conduction, which is simple to operate and safe and reliable; the discharge device has a simple structure and low manufacturing cost.

[0017] It is obvious that the above-mentioned fixed plate and movable plate are both made of insulating materials. The movable plate can be pulled out from under the fixed plate by using an additional mechanical device or manually pulling a wire. Because the number of discharges is very small according to the type test regulations, it is most convenient to manually pull out the movable plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a usage state diagram of an embodiment of the present invention;

[0019] Figure 2 Schematic diagram of the structure of a discharge trigger device according to an embodiment of the present invention.

[0020] In the figure, 1. first terminal board; 2. second terminal board; 3. first discharge block; 4. second discharge block; 4-1. bayonet; 5. Y-shaped groove; 6. discharge trigger device; 6-1. fixed plate; 6-2. movable plate; 6-3. conductive cylinder; 7. mounting through hole; 8. DC support capacitor; 8-1. terminal. DETAILED DESCRIPTION

[0021] The present invention is described in detail below in conjunction with embodiments.

[0022] See also Figure 1 A DC support capacitor impulse discharge test device comprises a first wiring board 1 and a second wiring board 2 arranged in parallel, a discharge gap installed on the first and second wiring boards, and a discharge trigger device 6.

[0023] Four mounting through holes 7 are provided at intervals along the length direction of the first and second wiring boards. The size of the mounting through holes 7 matches the outer diameter of the terminal 8-1 on the DC support capacitor 8. The spacing of the mounting through holes 7 is consistent with the spacing of the terminal 8-1 on the DC support capacitor 8. The mounting through holes 7 on the first wiring board 1 are strip-shaped through holes, and the length direction of the strip-shaped through holes is perpendicular to the arrangement direction of the mounting through holes 7.

[0024] The discharge gap includes a first discharge block 3 and a second discharge block 4. The bottoms of the first and second discharge blocks are respectively mounted on the middle of the first and second wiring boards. The adjacent parts of the tops of the first and second discharge blocks are each provided with a conductive inclined surface. The two conductive inclined surfaces and the two inner side surfaces of the first and second discharge blocks form a bottomless Y-shaped groove 5. The bottom of the second discharge block 4 is provided with a bayonet 4-1 for mounting a current sensor.

[0025] The discharge trigger device 6 includes a fixed plate 6-1, a movable plate 6-2 and a conductive cylinder 6-3. The fixed plate 6-1 is fixed to the top of the discharge block by bolts. A long through hole is provided in the center of the fixed plate 6-1. The length direction of the long through hole is parallel to the length direction of the Y-shaped groove 5, and the long through hole is located directly above the Y-shaped groove 5. A groove matching the size of the movable plate 6-2 is provided at the bottom of the fixed plate 6-1. The movable plate 6-2 is supported by the first and second discharge blocks and can be slidably installed in the groove. The diameter and length of the conductive cylinder 6-3 are adapted to the width and length of the long through hole. In the initial state of the test, the conductive cylinder 6-3 is supported by the movable plate 6-2 and stays in the long through hole. In this embodiment, the conductive cylinder 6-3 and the first and second discharge blocks are made of tungsten copper.

[0026] When the above-mentioned DC support capacitor impulse discharge test device is used, the two terminal plates are first installed on the terminal posts 8-1 on the two electrodes of the capacitor respectively, so that the two terminal plates are parallel and parallel, and then the position of the first terminal plate 1 is adjusted along the length direction of the strip through hole according to the discharge voltage to adjust the interval between the two discharge blocks, the fixed plate 6-1 is fixed to the top of the discharge block, the movable plate 6-2 is inserted into the groove at the bottom of the fixed plate 6-1 to block the long strip through hole of the fixed plate 6-1, and the conductive cylinder 6-3 is placed in the long strip through hole to complete the initial state setting of the test. When the capacitor is charged to the test voltage required for the test, the movable plate 6-2 is pulled out of the groove of the fixed plate 6-1 by remote control, and the conductive cylinder 6-3 falls from the long strip through hole into the Y-shaped groove 5. The conductive cylinder 6-3 connects the two conductive inclined surfaces to achieve discharge and complete a discharge test. Then, the movable plate 6-2 is inserted into the groove, and the conductive cylinder 6-3 is taken out of the Y-shaped groove 5 and placed in the long strip through hole to continue the next discharge test.

Claims

1. A DC support capacitor impulse discharge test device, characterized in that: It includes first and second wiring boards arranged in parallel, and a discharge gap and a discharge trigger device installed on the first and second wiring boards. The first and second wiring boards are provided with a plurality of mounting through holes at intervals along their length direction, the size of the mounting through holes matches the outer diameter of the terminal posts on the DC support capacitor, and the spacing of the mounting through holes is consistent with the spacing of the terminal posts on the DC support capacitor. The mounting through holes on the first wiring board and / or the second wiring board are strip-shaped through holes, and the length direction of the strip-shaped through holes is perpendicular to the arrangement direction of the terminal posts on the DC support capacitor. The discharge gap comprises a first discharge block and a second discharge block. The bottoms of the first discharge block and the second discharge block are respectively mounted on the middle of the first and second wiring boards. The adjacent parts of the tops of the first and second discharge blocks are each provided with a conductive inclined surface. The two conductive inclined surfaces and the two inner side surfaces of the first and second discharge blocks form a bottomless Y-shaped groove. The discharge trigger device comprises a fixed plate, a movable plate and a conductive cylinder. The fixed plate is horizontally arranged and fixed above the discharge block. A long through hole is arranged in the center of the fixed plate. The length direction of the long through hole is parallel to the length direction of the Y-shaped groove, and the long through hole is located directly above the Y-shaped groove. The movable plate can be slidably arranged horizontally between the fixed plate and the discharge block. The diameter and length of the conductive cylinder are adapted to the width and length of the long through hole. In the initial state of the test, the conductive cylinder is supported by the movable plate and stays in the long through hole. The fixed plate is fixed to the top of the discharge block by bolts. The bottom of the fixed plate is provided with a groove adapted to the size of the movable plate. The movable plate is supported by the first and second discharge blocks and stays in the groove. During the test, the first and second terminal blocks were inserted into the mounting through holes through the terminal posts and fixed on the top of the DC support capacitor. The current started from one electrode of the DC support capacitor, passed through the terminal post, the first terminal block, the first discharge block, the conductive inclined plane, the conductive cylinder, the conductive inclined plane, the second discharge block, the second terminal block, the terminal post, and returned to the other electrode of the DC support capacitor.

2. The DC support capacitor impulse discharge test device according to claim 1, characterized in that: A bayonet for mounting a current sensor is provided at the bottom of the first discharge block or the second discharge block.

3. The DC support capacitor impulse discharge test device according to claim 1, characterized in that: The conductive cylinder and the first and second discharge blocks are made of tungsten copper.

Images