CN118549684A - Large-current wide-voltage-range direct-current switch on-off test power supply system and method - Google Patents

Abstract

The present invention discloses a power supply system and method for testing the on-off of a DC switch with a large current and a wide voltage range. The power supply system includes a capacitor array discharge system and a combined series-parallel conversion switch unit. Two sets of the capacitor array discharge system are provided, and the two sets of capacitor array discharge systems are connected to the combined series-parallel conversion switch unit. The combined series-parallel conversion switch unit is provided with a two-stage terminal for outputting a current for outputting a test current. The input end of the combined series-parallel conversion switch unit is electrically connected to the output end of the two sets of capacitor array discharge systems and the output circuits of the two sets of capacitor array discharge systems are connected in series or in parallel to output the test current. The present invention discharges capacitors in series or in parallel through the combined series-parallel conversion switch unit, thereby achieving a test power supply output that meets the requirements of a large current and a wide voltage range without adding capacitors; the circuit is simple, the control is convenient, and the cost is low.

Description

A high current and wide voltage range DC switch on-off test power supply system and method

Technical Field

The present invention relates to the technical field of power supply testing, and in particular to a power supply system and method for testing an on-off power supply of a direct current switch with a large current and a wide voltage range.

Background Art

New energy sources such as electric vehicles, large-capacity energy storage systems, photovoltaics, and AC/DC distribution networks have achieved rapid development. The development of these new technologies is inseparable from the application of DC systems. DC systems require DC switches to close and disconnect circuits. Unlike AC systems, DC power supply systems do not cross zero during the disconnection process, and require higher switching capabilities of switches. Therefore, DC switch on-off testing is more meaningful. At present, the main test method for DC switch on-off is to use a large-capacity step-up isolation transformer to provide large current and high voltage for testing. However, due to the large current (40kA) and high voltage (1300V) required, the step-up isolation transformer that provides large current and high voltage requires a large capacity, resulting in a high cost for the step-up isolation transformer. Moreover, DC switches not only need to disconnect large currents but also small currents, and different DC switches require different test voltages. How to design low-cost test equipment with different breaking currents under a wide voltage range is of great significance to the development and reliability verification of DC switches.

In order to ensure a wide voltage range and high current on-off test of a DC switch while taking into account the low cost and multi-adaptability of the equipment, the present invention proposes a high current and wide voltage DC switch on-off test power supply system.

Summary of the invention

The purpose of the present invention is to solve the above technical problems and provide a large current and wide voltage range DC switch on-off test power supply system and method, which adopts a technical solution of capacitive energy storage discharge, IGBT switch control discharge on-off, and combined series-parallel conversion switch to achieve wide voltage discharge.

In order to achieve the above object, the present invention adopts the following technical solutions:

A high-current wide-voltage range DC switch on-off test power supply system includes a capacitor array discharge system and a combined series-parallel conversion switch unit, wherein two sets of the capacitor array discharge system are provided, and the two sets of capacitor array discharge systems are connected to the combined series-parallel conversion switch unit, and the combined series-parallel conversion switch unit is provided with a two-stage wiring terminal for outputting a test current; the input end of the combined series-parallel conversion switch unit is electrically connected to the output end of the two sets of capacitor array discharge systems, and the output circuits of the two sets of capacitor array discharge systems are connected in series or in parallel to output the test current. The two sets of capacitor array discharge systems can be operated in parallel or in series by selecting the parallel or series mode through the combined series-parallel switch, so that the test capability of low voltage and high current or high voltage and high current can be obtained.

Furthermore, the capacitor array discharge system includes multiple groups of capacitor energy storage discharge units connected in parallel, the capacitor energy storage discharge unit includes a capacitor, a discharge switch, and a discharge current limiting resistor, one end of the capacitor is electrically connected to one end of the discharge switch, the other end of the capacitor is connected to the combined series-parallel conversion switch unit, the other end of the discharge switch is electrically connected to one end of the discharge current limiting resistor, the other end of the discharge current limiting resistor is electrically connected to the input end of the combined series-parallel conversion switch unit, and the output end of the combined series-parallel conversion switch unit outputs the output current of the capacitor energy storage discharge unit after being connected in series or in parallel. By connecting the capacitors in multiple capacitor energy storage discharge units in parallel to form a capacitor pool, the battery capacity of the discharge system is increased, thereby providing a large current testing capability.

Furthermore, a diode is connected between the input end of the discharge current limiting resistor and the negative electrode of the capacitor, and the conduction direction of the diode is from the negative electrode of the capacitor to the input end of the discharge current limiting resistor. After the discharge is completed, the diode is used for continuous current in the discharge circuit to protect the discharge switch.

Furthermore, the capacitor is an electrolytic capacitor; the discharge switch is an IGBT switch, and the gate of the IGBT switch is electrically connected to the control signal transmission line.

Furthermore, the combined series-parallel conversion switch unit includes a parallel switching switch and a series switching switch corresponding to the capacitor array discharge system. When the parallel switching switch is closed and the series switching switch is disconnected, the capacitor energy storage discharge unit is connected in parallel to output the test current. When the series switching switch is closed and the parallel switching switch is disconnected, the capacitor energy storage discharge unit is connected in series to output the test current.

Furthermore, it also includes a charging module, which includes a step-up isolation transformer and a rectifier module, and the output of the step-up isolation transformer is connected to the rectifier module; the output positive electrode of the rectifier module is connected in series with one end of the first charging current limiting resistor, the other end of the first charging current limiting resistor is electrically connected to the positive electrode of the capacitor in the capacitor energy storage and discharge unit, and the output negative electrode of the rectifier module is electrically connected to the negative electrode of the capacitor.

Furthermore, the output end of the rectifier module is respectively connected to a plurality of capacitor energy storage and discharge units to realize charging of a plurality of capacitors.

Furthermore, a second charging current limiting resistor and a fuse are connected in series to the input positive electrode of the capacitor in the capacitor energy storage and discharge unit connected to the rectifier module.

Furthermore, the discharge current limiting resistor adopts a stainless steel resistor, including a fixed plate, and a resin plate is fixedly connected at the upper and lower edges of the fixed plate, and the resin plate is an epoxy resin plate, and a resistor steel plate is fixedly connected on the resin plate, and the resistor steel plate is cut from a stainless steel plate, and the resistor steel plate includes a plurality of first straight plates arranged side by side and a series connection plate connected between the ends of the first straight plates, and adjacent series connection plates are arranged in an upper and lower staggered manner to connect the first straight plates in series. The discharge current limiting resistor adopts a resistor made of stainless steel plate, which has a small resistance, stable resistance, and large capacity, and can meet the requirements of large current and high voltage passing.

On the other hand, the present invention provides a control method for a high current and wide voltage range DC switch on-off test power supply, according to the following method:

The method adopts multiple capacitor discharges to provide a test power supply for the on-off test of the DC switch, connects some capacitors in parallel to form a capacitor array discharge system, forms multiple capacitor array discharge systems, and connects different capacitor array discharge systems to a combined series-parallel conversion switch unit. When high voltage and high current output is required, the output circuits of the multiple capacitor array discharge systems are switched to a series connection through the combined series-parallel conversion switch unit to realize the series output test current of the capacitor array discharge system; when low voltage and high current output is required, the output circuits of the multiple capacitor array discharge systems are switched to a parallel connection through the combined series-parallel conversion switch unit to realize the parallel output test current of the capacitor array discharge system.

The present invention provides a large current and wide voltage range DC switch on-off test power supply system and method, which has the following beneficial effects: by arranging a combined series-parallel conversion switch unit circuit at the output end of multiple capacitor array discharge systems, the capacitor array discharge systems are discharged in series or in parallel through the combined series-parallel conversion switch unit, thereby achieving a test power supply output that meets the requirements of large current and wide voltage range with fewer capacitors; the circuit is simple, the control is convenient, the cost is low, and the output voltage width is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings:

FIG1 is a circuit diagram of a high-current, wide-voltage range DC switch on-off test power supply system provided by the present invention;

2 is a partial circuit diagram of a capacitor energy storage discharge unit and a combined series-parallel conversion switch unit in a large current and wide voltage range DC switch on-off test power supply system provided by the present invention;

FIG3 is a circuit diagram of a capacitor energy storage and discharge unit in the present invention;

FIG. 4 is a schematic diagram of the structure of the discharge current limiting resistor in the present invention.

Explanation of the numbers in the figure: 1. Capacitor energy storage discharge unit; C1. Capacitor; S. Discharge switch; R1. Discharge current limiting resistor; 2. Combined series-parallel conversion switch unit; 21. Series switching switch; 22. Parallel switching switch; 3. Charging module; 31. Boost isolation transformer; 32. Rectifier module; Rd. First charging current limiting resistor; Rc. Second charging current limiting resistor; FU. Fuse; D. Diode; Z. Capacitor array discharge system; 11. Fixed plate; 12. Resin plate; 13. Resistance steel plate; 131. First straight plate; 132. Series plate.

DETAILED DESCRIPTION

It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Application Overview:

In the DC switch product test, when the DC switch is required to pass a large current (40kA), the DC switch needs to be disconnected for testing; so that when the circuit in which the DC switch is used is short-circuited and generates a large short-circuit current, the DC switch can be disconnected to protect the connected circuit. In order to test this function of the DC switch, the DC switch needs to be tested, and the test power supply needs to be able to provide an instantaneous power supply with a current of up to 40kA, and the voltage can cover the range of 300V to 1500V, so as to meet the test of different models of DC switch products with different rated voltages.

The traditional transformer type test power supply uses the principle of electromagnetic induction to transform the power supply to the required test voltage by changing the turns ratio between the primary coil and the secondary coil. However, due to the large test current requirements and high voltage, the transformer needs to have a large capacity, a large transformer structure, high cost, and a large short-circuit capacity requirement for the power supply.

To this end, the inventors proposed a test power supply solution using multiple groups of capacitor pools for discharge, each group of capacitor pools corresponding to multiple stainless steel current limiting resistors, and controlling the discharge principle through IGBT semiconductor switches.

The scheme is determined: in order to meet different DC switch tests, according to the DC switch working voltage, the test voltage needs to be able to meet the test of the DC switch with a voltage of 300V to 1500V and a current of 0 to 40kA. In order to achieve high voltage output, considering that the conventional electrolytic capacitor has a low withstand voltage, it is necessary to set multiple capacitors in series to meet the high voltage requirements; at 1500V, electrolytic capacitors need to be connected in series, and at this time, the capacitance of the capacitors decreases after the series connection, which will cause the effective capacity of the capacitors to decrease. During low-voltage testing, due to the voltage reduction, the output current of the series capacitor group designed for high voltage is reduced, and the requirements of 40kA current under low voltage cannot be met. From the perspective of high voltage and high current, low voltage and high current, and energy storage capacitor cost, the present invention is to improve the effective utilization of the energy storage capacitor pool capacity, divide the entire test equipment capacitor pool into two groups of arrays, switch through a series-parallel combination switch, and operate the two groups of capacitor arrays in series when the high voltage and high current are large; when the low voltage and high current are large, the two capacitor arrays are operated in parallel.

Example systems:

As shown in Figures 1 to 3, a large current and wide voltage range DC switch on-off test power supply system includes a capacitor array discharge system Z and a combined series-parallel conversion switch unit 2, wherein the capacitor array discharge system Z is provided with two sets, and the two sets of capacitor array discharge systems Z are connected to the combined series-parallel conversion switch unit 2, and the combined series-parallel conversion switch unit 2 is provided with a two-stage wiring terminal for outputting a test current, namely, a positive wiring terminal OUT+ and a negative wiring terminal OUT- of the output current. During the test, the input end of the DC switch to be tested is electrically connected to the two-stage wiring terminal of the output current respectively; the input end of the combined series-parallel conversion switch unit 2 is electrically connected to the output end of the two sets of capacitor array discharge systems Z, and the output circuits of the two sets of capacitor array discharge systems Z are connected in series or in parallel to output the test current.

Through the above technical scheme, the on-off test of the DC switch needs to provide a large current and wide voltage test power supply. For example, if the current reaches 40kA and the test voltage reaches 300V-1500V, the capacitor C1 is used to store electric energy, and the discharge of the capacitor C1 is controlled by the discharge switch S. The discharge end of the capacitor C1 is connected in series through the combined series-parallel conversion switch unit 2, thereby increasing the discharge voltage; when low voltage is required, the capacitor C1 is connected in parallel to achieve low voltage output, thereby achieving a wide range of voltage output; and the discharge amount of the capacitor is controlled by the discharge switch S between multiple gears for more accurate control.

Specifically, the capacitor array discharge system Z can be set to multiple groups according to needs, and then different capacitor array discharge systems Z are connected in parallel or in series to output the test current, thereby increasing the voltage range.

Specifically, the capacitor array discharge system Z includes a plurality of groups of capacitor energy storage discharge units 1 connected in parallel with each other, wherein the capacitor energy storage discharge unit 1 includes a capacitor C1, a discharge switch S, and a discharge current limiting resistor R1, wherein one end of the capacitor C1 is electrically connected to one end of the discharge switch S, and the other end of the capacitor C1 is connected to a combined series-parallel conversion switch unit 2, and the other end of the discharge switch S is electrically connected to one end of the discharge current limiting resistor R1, and the other end of the discharge current limiting resistor R1 is electrically connected to an input end of the combined series-parallel conversion switch unit 2, and the output end of the combined series-parallel conversion switch unit 2 outputs the output current of the capacitor energy storage discharge unit 1 after being connected in series or in parallel.

Specifically, a diode D is connected between the input end of the discharge current limiting resistor R1 and the negative electrode of the capacitor C1, and the conduction direction of the diode D is from the negative electrode of the capacitor C1 to the input end of the discharge current limiting resistor R1. After the discharge is completed, the diode D is used for continuous current in the discharge circuit to protect the discharge switch S.

Specifically, the capacitor C1 is an electrolytic capacitor. In order to achieve a test under a wide voltage range from low voltage to high voltage measurement, a higher maximum test voltage is required, and the required storage energy is large. The capacitor C1 will generate heat when there is internal resistance, and other resistors will generate large heat; while the electrolytic capacitor has a small resistance, thereby reducing the heat generated by the test power supply under high current and high voltage conditions.

Specifically, the discharge switch S adopts an IGBT switch, the gate G of the IGBT switch is electrically connected to the control signal transmission line, wherein the collector C of the IGBT switch is electrically connected to the positive electrode of the capacitor, and the emitter E of the IGBT switch is connected to the discharge current limiting resistor R1. The discharge switch S of the test circuit uses an IGBT semiconductor switch, which has a fast response speed, can pass a large current, and can quickly realize the on-off control of the discharge circuit; the power-on time of the discharge circuit is controlled by the control signal, thereby protecting the tested DC switch and avoiding damage to the tested DC switch caused by long-term discharge. The tested DC switch must be automatically disconnected when it is powered on for 5ms. If the DC switch cannot be disconnected, continuous loading of the test current will damage the switch; the closing time of the discharge switch S is set by the pulse width of the control signal to control the discharge time of the discharge circuit by 5ms, so as to achieve accurate control, thereby avoiding long-term discharge and ensuring the safety of the test circuit.

The combined series-parallel conversion switch unit 2 includes a series switch 21 and a parallel switch 22 corresponding to the capacitor array discharge system Z. When the parallel switch is closed and the series switch is disconnected, the capacitor energy storage discharge unit 1 is connected in parallel to output a test current. When the series switch is closed and the parallel switch is disconnected, the capacitor energy storage discharge unit 1 is connected in series to output a test current. The connection circuit of the parallel switch and the series switch in the combined series-parallel conversion switch unit 2 is matched and connected by a person skilled in the art according to the number of capacitor energy storage discharge units 1 to realize the series-parallel switching function of the capacitor energy storage discharge unit 1. As shown in Figures 1 and 4, the series switch is a series switch combination composed of switches Q1, Q2, Q3, and Q4, and the series switch combination control signal QC1 is used to control the series switch to be closed or disconnected; the parallel switch is a parallel switch combination composed of switches Q5, Q6, Q7, and Q8, and the parallel switch combination control signal QC2 is used to control the parallel switch to be closed or disconnected.

Specifically, it also includes a charging module 3, which includes a step-up isolation transformer 31 and a rectifier module 32. The output of the step-up isolation transformer 31 is connected to the rectifier module 32; the output positive electrode of the rectifier module 32 is connected in series with one end of the first charging current limiting resistor Rd, and the other end of the first charging current limiting resistor Rd is electrically connected to the positive electrode of the capacitor C1 in the capacitor energy storage and discharge unit 1, and the output negative electrode of the rectifier module 32 is electrically connected to the negative electrode of the capacitor C1.

Specifically, the output end of the rectifier module 32 is respectively connected to a plurality of capacitor energy storage and discharge units 1 to realize charging of a plurality of capacitors C1. The capacitors in the plurality of capacitor energy storage and discharge units 1 are charged by the charging module 3, thereby improving the charging efficiency. At the same time, multiple groups of charging modules 3 can also be set, and the plurality of capacitor energy storage and discharge units 1 are grouped and respectively connected to the plurality of charging modules 3, so that each group of charging modules 3 charges the capacitors C1 in some capacitor energy storage and discharge units 1, and the charging is performed by the plurality of charging modules 3, thereby improving the charging efficiency and facilitating the control.

Specifically, the second charging current limiting resistor Rc and the fuse FU are connected in series to the input positive electrode of the capacitor C1 in the capacitor energy storage and discharge unit 1 connected to the rectifier module 32. The second charging current limiting resistor Rc and the fuse FU are connected in series to the charging end of the capacitor C1, and the charging current is limited by the second charging current limiting resistor Rc, and the fuse FU is used for protection, thereby improving the charging safety.

Specifically, as shown in FIG4 , the discharge current limiting resistor R1 is a stainless steel resistor, including a fixed plate 11, and a resin plate 12 is fixedly connected to the upper and lower edges of the fixed plate 11, and the resin plate 12 is an epoxy resin plate, and a resistor steel plate 13 is fixedly connected to the resin plate 12, and the resistor steel plate 13 is cut from a stainless steel plate, and the resistor steel plate 13 includes a plurality of first straight plates 131 arranged side by side and a series connection plate 132 connected between the ends of the first straight plates 131, and adjacent series connection plates 132 are arranged in an offset manner up and down to connect the first straight plates 131 in series. The discharge current limiting resistor R1 is a resistor made of a stainless steel plate, which has a small resistance, stable resistance, and large capacity, and can meet the requirements of large current and large voltage passing.

Exemplary methods:

A control method for a high current and wide voltage range DC switch on-off test power supply is as follows:

A test power supply for switching on and off a DC switch is provided by discharging multiple capacitors C1, and some capacitors C1 are connected in parallel to form a capacitor array discharge system Z to form multiple capacitor array discharge systems Z, and different capacitor array discharge systems Z are connected to a combined series-parallel conversion switch unit 2. When high voltage and high current output is required, the output circuits of the multiple capacitor array discharge systems Z are switched to a series connection through the combined series-parallel conversion switch unit 2 to realize the series output test current of the capacitor array discharge system Z; when low voltage and high current output is required, the output circuits of the multiple capacitor array discharge systems Z are switched to a parallel connection through the combined series-parallel conversion switch unit 2 to realize the parallel output test current of the capacitor array discharge system Z.

When testing:

The test power supply device of the present invention selects the series and parallel connection of the capacitor array discharge system Z according to the set voltage. If the voltage is greater than the set value, the capacitor array discharge system Z is selected to be connected in series. If it is less than or equal to the set value, the capacitor array discharge system Z is connected in parallel, and the charging target voltage is calculated accordingly, the capacitor pool is charged to the target voltage, and the discharge circuit is calculated and selected according to the discharge current size.

For example: the test power supply device of the present invention selects the series and parallel connection of the capacitor array discharge system Z according to the set voltage. If the test voltage required by the DC switch is greater than 800V, the capacitor array discharge system Z is selected in series. If the test voltage required by the DC switch is less than or equal to 800V, the capacitor array discharge system Z is connected in parallel, and the charging target voltage is calculated accordingly, the capacitor is charged to the target voltage, and the discharge circuit is calculated and selected according to the discharge current size.

For example, as shown in FIG1 , after the capacitor C1 is charged, the combined series-parallel switch working state in the combined series-parallel conversion switch unit 2 is selected according to the above-mentioned series-parallel discharge mode. When the series discharge mode is selected, the series switch 21 is switched to a valid state through the series switch combination control signal QC1, and the parallel switch 22 is switched to an invalid state through the parallel switch combination control signal QC2. The switches Q1, Q2, Q3, and Q4 included in the series switch 21 are all turned on, and the switches Q5, Q6, Q7, and Q8 included in the parallel switch 22 are all turned off, and the capacitor array is discharged. System Z and another capacitor array discharge system Z can form a series discharge effect through each discharge switch; when the parallel mode is selected, the parallel switching switch 22 is controlled to be in an effective state through the parallel switch combination control signal QC2, and the series switching switch 21 is controlled to be in an invalid state through the series switch combination control signal QC1. The switches Q5, Q6, Q7, and Q8 included in the parallel switching switch 22 are all turned on, and at the same time, the switches Q1, Q2, Q3, and Q4 included in the series switching switch 21 are all turned off. The capacitor array discharge system Z and another capacitor array discharge system Z can form a parallel discharge effect through each discharge switch.

The parts not involved in this technical solution can be implemented by using existing technologies.

The above shows and describes the basic principles, main features and characteristics of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims (10)

1. A high-current wide-voltage range DC switch on-off test power supply system, characterized in that it comprises a capacitor array discharge system (Z) and a combined series-parallel conversion switch unit (2), wherein the capacitor array discharge system (Z) is provided with two sets, and the two sets of capacitor array discharge systems (Z) are connected to the combined series-parallel conversion switch unit (2), and the combined series-parallel conversion switch unit (2) is provided with a two-stage wiring terminal for outputting a test current; the input end of the combined series-parallel conversion switch unit (2) is electrically connected to the output end of the two sets of capacitor array discharge systems (Z), and the output circuits of the two sets of capacitor array discharge systems (Z) are connected in series or in parallel to output the test current. 2. A high current wide voltage range DC switch on/off test power supply system according to claim 1, characterized in that: the capacitor array discharge system (Z) comprises a plurality of groups of capacitor energy storage discharge units (1) connected in parallel with each other, the capacitor energy storage discharge unit (1) comprises a capacitor (C1), a discharge switch (S), and a discharge current limiting resistor (R1), one end of the capacitor (C1) is electrically connected to one end of the discharge switch (S), the other end of the capacitor (C1) is connected to a combined series-parallel conversion switch unit (2), the other end of the discharge switch (S) is electrically connected to one end of the discharge current limiting resistor (R1), the other end of the discharge current limiting resistor (R1) is electrically connected to the input end of the combined series-parallel conversion switch unit (2), and the output end of the combined series-parallel conversion switch unit (2) outputs the output current of the capacitor energy storage discharge unit (1) after being connected in series or in parallel. 3. A large current and wide voltage range DC switch on-off test power supply system according to claim 2, characterized in that: a diode (D) is connected between the input end of the discharge current limiting resistor (R1) and the negative electrode of the capacitor (C1), and the conduction direction of the diode (D) is from one end of the negative electrode of the capacitor (C1) to the input end of the discharge current limiting resistor (R1). 4. A large current and wide voltage range DC switch on-off test power supply system according to claim 2, characterized in that: the capacitor (C1) adopts an electrolytic capacitor; the discharge switch (S) adopts an IGBT switch, and the gate of the IGBT switch is electrically connected to the control signal transmission line. 5. A high-current wide-voltage range DC switch on-off test power supply system according to claim 2, characterized in that: the combined series-parallel conversion switch unit (2) includes a parallel switching switch (22) and a series switching switch (21) corresponding to the capacitor array discharge system (Z), when the parallel switching switch (22) is closed and the series switching switch (21) is disconnected, the capacitor energy storage discharge unit (1) is connected in parallel to output the test current, and when the series switching switch (21) is closed and the parallel switching switch (22) is disconnected, the capacitor energy storage discharge unit (1) is connected in series to output the test current. 6. A high-current wide-voltage range DC switch on-off test power supply system according to claim 2, characterized in that: it also includes a charging module (3), the charging module (3) includes a step-up isolation transformer (31) and a rectifier module (32), the output of the step-up isolation transformer (31) is connected to the rectifier module (32); the output positive electrode of the rectifier module (32) is connected in series with one end of a first charging current limiting resistor (Rd), the other end of the first charging current limiting resistor (Rd) is electrically connected to the positive electrode of the capacitor (C1) in the capacitor energy storage and discharge unit (1), and the output negative electrode of the rectifier module (32) is electrically connected to the negative electrode of the capacitor (C1). 7. A high-current, wide-voltage range DC switch on-off test power supply system according to claim 6, characterized in that: the output end of the rectifier module (32) is respectively connected to a plurality of capacitor energy storage and discharge units (1) to realize charging of a plurality of capacitors (C1). 8. A high-current, wide-voltage range DC switch on-off test power supply system according to claim 7, characterized in that: a second charging current limiting resistor (Rc) and a fuse (FU) are connected in series to the input positive electrode of the capacitor (C1) in the capacitor energy storage and discharge unit (1) connected to the rectifier module (32). 9. A large current wide voltage range DC switch on-off test power supply system according to claim 2, characterized in that: the discharge current limiting resistor (R1) adopts a stainless steel resistor, including a fixed plate (11), and a resin plate (12) is fixedly connected to the upper and lower edges of the fixed plate (11), and the resin plate (12) is an epoxy resin plate (12), and a resistance steel plate (13) is fixedly connected to the resin plate (12), and the resistance steel plate (13) is cut from a stainless steel plate, and the resistance steel plate (13) includes a plurality of first straight plates (131) arranged side by side and a series connection plate (132) connected between the ends of the first straight plates (131), and adjacent series connection plates (132) are arranged in an upper and lower staggered manner so as to connect the first straight plates (131) in series. 10. A control method for a high current wide voltage range DC switch on-off test power supply, using a high current wide voltage range DC switch on-off test power supply system as claimed in any one of claims 2 to 9, characterized in that: A plurality of capacitors (C1) are used to discharge and provide a test power supply for switching on and off a direct current switch, some capacitors (C1) are connected in parallel to form a capacitor array discharge system (Z), forming a plurality of capacitor array discharge systems (Z), and different capacitor array discharge systems (Z) are connected to a combined series-parallel conversion switch unit (2); when a high voltage and high current output is required, the output circuits of the plurality of capacitor array discharge systems (Z) are switched to a series connection through the combined series-parallel conversion switch unit (2) to realize the capacitor array discharge system (Z) outputs a test current in series; when a low voltage and high current output is required, the output circuits of the plurality of capacitor array discharge systems (Z) are switched to a parallel connection through the combined series-parallel conversion switch unit (2) to realize the capacitor array discharge system (Z) outputs a test current in parallel.