Topological structure of high-frequency high-voltage power supply

Abstract

The invention relates to a high-frequency high-voltage power supply topological structure, which comprises a cascade multi-level module, a charging power supply module, an isolation high-frequency alternating current module and an isolation direct current module, and is characterized in that a series circuit of the charging power supply module and the isolation high-frequency alternating current module is connected to the head alternating current end and the tail alternating current end of the cascade multi-level module; a series circuit of the isolation direct current module and the equipment to be tested is connected to the head and tail alternating current ends of the cascade multi-level module; according to the invention, the structure is simple, high-frequency and high-voltage output can be realized by only needing power electronic devices and constructing a power frequency power supply, an inductor, a resistor and a capacitor, the voltage amplitude and frequency output range is wide, high-frequency and high-voltage alternating current can be output, the voltage endurance capability of a high-voltage to-be-tested product can be tested, the topological structure is simple, the real-time operation is convenient, and the cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of high-frequency and high-voltage test power supplies, and in particular to a high-frequency and high-voltage power supply topology structure. Background Art

[0002] With the development of flexible DC transmission technology, modular multi-level technology is widely used in the field of flexible DC transmission. In flexible DC transmission projects, each bridge arm of the converter valve is usually equipped with hundreds of power modules, which are usually composed of half-bridge / full-bridge modules in series. Although the more series-connected power modules in the modular multi-level converter valve, the better the level approximation effect, it contains harmonics around the equivalent switching frequency of the bridge arm, which is usually several thousand hertz to more than ten kilohertz. In addition, the control cycle of the converter valve controller is usually at the level of 50 microseconds, and high-frequency harmonics are also introduced in the AC system of the flexible DC converter valve. In recent years, in the actual projects of flexible DC transmission, high-frequency harmonics have damaged the electrical equipment in the system and affected the operation of the system. Therefore, it is necessary to test the high-frequency and high-voltage tolerance of high-voltage equipment in the system, such as AC switches, insulators and insulating bushings, so it is necessary to have power supply equipment that can output high-frequency and high-voltage.

[0003] At present, there are few high-frequency and high-voltage AC power supply devices, and there is no mature technology that can be directly applied. Usually, customized test equipment is used. For example, the Chinese patent with publication number CN118337070A, an invention patent for a power supply device and test method for high-frequency and high-voltage insulation testing, requires the coordination of pre-charging power supply, energy replenishment power supply and switch in the proposed high-frequency and high-voltage power supply topology, but it has high manufacturing cost and complex implementation operation. Summary of the invention

[0004] The present invention provides a high-frequency and high-voltage power supply topology structure, which can output high-frequency and high-voltage alternating current and realize the withstand voltage test of high-voltage products to be tested. The topology structure is simple, the real-time operation is convenient, and the cost is low.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A high-frequency and high-voltage power supply topology structure comprises a cascaded multi-level module, a charging power module, an isolated high-frequency AC module and an isolated DC module, wherein a series circuit of the charging power module and the isolated high-frequency AC module is connected to the first and last AC ends of the cascaded multi-level module, and a series circuit of the isolated DC module and a product to be tested is connected to the first and last AC ends of the cascaded multi-level module.

[0007] The charging power supply module comprises an AC power supply, a charging circuit and a three-phase diode bridge circuit, wherein the charging circuit comprises an adjustable transformer or a starting circuit, and the AC power supply, the charging circuit and the three-phase diode bridge circuit are connected in series.

[0008] Furthermore, the cascade multi-level module is composed of a plurality of full-bridge power units connected in series, the full-bridge power units are connected in full-bridge form using silicon carbide, MOS tubes or freewheeling diodes, and the full-bridge AC output ends are connected end to end in sequence to form a cascade multi-level structure.

[0009] Furthermore, the startup circuit includes a pre-charging resistor and a bypass switch, and the pre-charging resistor is connected in parallel with the bypass switch.

[0010] Furthermore, the isolated high-frequency AC module is an inductor, or a parallel circuit of a resistor and a capacitor connected in series with an inductor.

[0011] Furthermore, the isolated DC module includes an isolated DC circuit composed of a capacitor, an inductor and a resistor.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1) The present invention has a simple structure. It can realize high-frequency and high-voltage output by only using a power supply, an inductor, a resistor and a capacitor. The voltage amplitude and frequency output range are wide. In addition, without the need for other power supply injection, the topology can realize the output of industrial frequency AC voltage superimposed on high-frequency AC voltage;

[0014] 2) The live operation mode of the power devices in the cascaded multi-level module of the present invention is simple and is completely provided by the charging power module. At the same time, when the test product tolerance test is performed, the charging power module plays an energy replenishment role without any other auxiliary devices, which greatly reduces the system cost and test difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention.

[0016] Figure 2 Schematic diagram of a topological structure of a cascaded multi-level module containing three groups of full-bridge modules according to an embodiment of the present invention.

[0017] Figure 3 It is a voltage distribution diagram of each port in the topological structure described in the embodiment of the present invention.

[0018] In the figure: 1. Charging power module 2. Cascade multi-level module 3. Full-bridge power unit DETAILED DESCRIPTION

[0019] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0020] See Figure 1, is a schematic diagram of the structure of the present invention. A high-frequency and high-voltage power supply topology structure of the present invention comprises a cascaded multi-level module 2, a charging power supply module 1, an isolated high-frequency AC module and an isolated DC module, wherein the charging power supply module 1 is connected in series with the isolated high-frequency AC module to prevent the high-frequency component from affecting the charging power supply module 1, and the series circuit of the charging power supply module 1 and the isolated high-frequency AC module is further connected to the Line_in and Line_out ends of the cascaded multi-level module 2, wherein the cascaded multi-level module 2 is composed of a plurality of full-bridge power units 3 connected in series, and the test product module to be tested is connected in series with the isolated DC module and then connected to the Line_in and Line_out ends of the cascaded multi-level module 2; the test product module is a high-frequency and high-voltage test product to be tested, and comprises electrical equipment such as an AC switch, an insulator and an insulating bushing.

[0021] The full-bridge power unit 3 of the cascade multi-level module 2 is connected in a full-bridge form using silicon carbide, MOS tubes or freewheeling diodes. The full-bridge AC output ends are connected in sequence to form a cascade multi-level structure. The number of cascade power units can be flexibly adjusted to adjust the port voltage. Since the capacitor of the full-bridge power unit 3 is connected in series on the DC side, its energy acquisition method is simple. The wiring method of the full-bridge power unit 3 containing 3 groups of power units in the cascade multi-level module 2 is shown in FIG. Figure 2 .

[0022] The charging power supply module 1 is used for charging and energy replenishment, and includes an AC power supply, a charging circuit and a three-phase diode bridge circuit. The charging circuit includes an adjustable transformer or a starting circuit. The AC power supply is connected in series with the adjustable transformer or the starting circuit, and then connected in series with the three-phase diode bridge. The charging circuit includes an adjustable transformer or a starting circuit, and charges the cascaded multi-level module 2. After the cascaded multi-level module 2 is charged, the product to be tested is tested and unlocked, and the charging power supply module 1 plays an energy replenishment role. The circuit in the charging power supply module 1 can select an adjustable transformer or a starting circuit, and the starting circuit is composed of a bypass switch K and a pre-charging resistor R.

[0023] The isolated high-frequency AC module is used to suppress high-frequency AC components and is connected in series with the charging power module 1 , and is an inductor, or a parallel circuit of a resistor and a capacitor and then connected in series with an inductor.

[0024] The cascade multi-level module 2 is used to generate a high-frequency and high-voltage AC component. The full-bridge power units 3 in the module are connected in a cascade manner. The charging power module 1 charges the capacitors of each full-bridge power unit 3. The charging form is simple. After the cascade multi-level module 2 is unlocked, the cascade multi-level module 2 outputs a given high-frequency and high-voltage AC power and applies it to both ends of the test product. The energy loss during the unlocking operation can be continuously provided by the charging power module 1. Due to the existence of the isolated high-frequency AC module, the high-frequency and high-voltage AC generated by the cascade multi-level module 2 will not affect the charging power module 1.

[0025] The isolated DC module is used to suppress the effect of the DC component. Since the test module tests the AC tolerance of high voltage and high frequency, the existence of the isolated DC module can avoid the influence of the DC component on the test module. The isolated DC module can be selected according to specific needs.

[0026] See Figure 3 , the charging circuit selects the startup circuit, the isolated high-frequency AC module selects the inductor L to form a single unit, and the isolated DC module selects the capacitor C to form a unit; the cascaded multi-level module 2 is uncontrolled charged through the pre-charging resistor R, and after the DC voltage of the full-bridge power unit 3 in the cascaded multi-level module 2 is stable, the bypass switch K in the startup circuit is closed to perform controllable charging, so that the DC voltage of the full-bridge power unit 3 in the cascaded multi-level module 2 is higher than the minimum operating voltage requirement of the equipment; according to the high-frequency and high-voltage AC voltage tolerance required by the test module, the cascaded multi-level module 2 is unlocked. After the cascaded multi-level module 2 is unlocked and operated, the distribution of the voltages of each part in the topology is as follows Figure 3 As shown, the two ends of the three-phase diode bridge are DC voltages, the output end of the cascaded multi-level module 2 is a DC voltage with a high-frequency component, and the two ends of the test module are high-voltage and high-frequency AC voltages.

[0027] The above embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the above embodiments. The methods used in the above embodiments are conventional methods unless otherwise specified.

Claims

1. A high-frequency and high-voltage power supply topology structure, characterized in that: The device comprises a cascade multi-level module, a charging power module, an isolated high-frequency AC module and an isolated DC module. The series circuit of the charging power module and the isolated high-frequency AC module is connected to the head and tail AC ends of the cascade multi-level module, and the series circuit of the isolated DC module and the product to be tested is connected to the head and tail AC ends of the cascade multi-level module.

2. A high-frequency and high-voltage power supply topology structure according to claim 1, characterized in that: The cascade multi-level module is composed of a plurality of full-bridge power units connected in series. The full-bridge power units are connected in full-bridge form using silicon carbide, MOS tubes or freewheeling diodes. The full-bridge AC output ends are connected end to end in sequence to form a cascade multi-level structure.

3. A high-frequency and high-voltage power supply topology structure according to claim 1, characterized in that: The charging power supply module comprises an AC power supply, a charging circuit and a three-phase diode bridge circuit, wherein the charging circuit comprises an adjustable transformer or a starting circuit, and the AC power supply, the charging circuit and the three-phase diode bridge circuit are connected in series.

4. A high-frequency and high-voltage power supply topology structure according to claim 3, characterized in that: The startup circuit includes a pre-charging resistor and a bypass switch, and the pre-charging resistor is connected in parallel with the bypass switch.

5. A high-frequency and high-voltage power supply topology structure according to claim 1, characterized in that: The isolated high-frequency AC module is an inductor, or a parallel circuit of a resistor and a capacitor connected in series with an inductor.

6. A high-frequency and high-voltage power supply topology structure according to claim 1, characterized in that: The isolated DC module includes an isolated DC circuit composed of a capacitor, an inductor and a resistor.

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