A high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source

Abstract

The application relates to a high-voltage, high-frequency and pulse waveform adjustable high-voltage partial discharge test source, belonging to the technical field of high-voltage electrical equipment partial discharge test. The application comprises a direct current power supply, a direct current power supply internal resistance, a total switch and n-stage unit circuits; each stage unit circuit is composed of an energy storage capacitor, three solid-state switches and two diodes. Through switch timing control, the circuit can sequentially complete charging, positive polarity discharge, positive polarity truncation, negative polarity discharge and negative polarity truncation, and output a bipolar square wave pulse. Compared with a traditional bipolar Marx circuit, the application reduces half of the devices, has a simple structure, low loss and simple control; diode isolation is adopted to realize fast equalization charging of the capacitors of all stages, the charging current is large, and voltage consistency is good; the application has a steep rising edge, fast truncation and no tailing; the pulse amplitude, pulse width, frequency and polarity can be flexibly adjusted.

Description

Technical Field

[0001] This invention relates to a high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source circuit, belonging to the field of high-voltage electrical equipment partial discharge test technology. Background Technology

[0002] The partial discharge characteristics of high-voltage electrical equipment (such as GIS, transformers, cables, etc.) are the core indicators for evaluating their insulation status and ensuring the safe operation of the power grid. Existing partial discharge test sources mainly have the following technical defects: (1) Most test sources can only output unipolar pulses and cannot simulate the bipolar transient overvoltages (such as switching overvoltages and lightning overvoltages) that actually exist in the power grid. The test scenario deviates from the actual working conditions; (2) Traditional Marx generators and other boost circuits are limited by the withstand voltage of switching devices, making it difficult to achieve high amplitude pulse output under high frequency conditions. Moreover, the pulse rise edge and pulse width adjustment flexibility are poor. In addition, each stage of the Marx generator uses 6 IGBTs and diodes, and its circuit is loose and has a large energy loss; (3) Under high frequency and high voltage conditions, the reverse recovery loss and conduction loss of traditional switching devices are large, which can easily lead to overheating of the devices and affect the long-term stable operation of the test source; (4) In multi-stage series circuits, the charging voltage of each stage capacitor is unbalanced, resulting in fluctuations in the output pulse amplitude, which cannot meet the requirements of high-precision partial discharge testing.

[0003] Therefore, there is an urgent need to develop a partial discharge test source that can output bipolar square waves, has adjustable waveform parameters, operates at high frequency and high voltage, and is reliable in operation, so as to meet the partial discharge test requirements of different voltage levels and different types of high voltage equipment. Summary of the Invention

[0004] This invention proposes a high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source circuit. Its purpose is to achieve bipolar square wave pulse output, accurately simulate transient overvoltages in the actual operation of high-voltage equipment, and flexibly adjust the amplitude, pulse width, and repetition frequency of the output pulse to adapt to different test scenarios. It can also reduce switching losses, improve the operational reliability of the circuit under high-frequency and high-voltage conditions, ensure the balanced charging voltage of each capacitor, and improve the consistency and stability of the output pulse.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] A high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source, including a DC power supply. DC power supply internal resistance r, main switch , Level unit circuits and loads;

[0007] The DC power supply The positive terminals are connected in series with the internal resistance r of the DC power supply and the main switch. Then, the DC power supply is connected to the input terminal of the first-stage unit circuit. The negative terminal is grounded;

[0008] Each unit circuit includes an energy storage capacitor. , First solid-state switch Second solid-state switch Third solid-state switch First diode Second diode , ,

[0009] In a single channel of the same level unit, the first diode The anode serves as the input terminal of this stage, and the first diode... Cathode connected to energy storage capacitor The upper electrode plate, the first solid-state switch First terminal and second diode Cathode; Second diode The anodes are connected together to the main switch. Output terminal; energy storage capacitor The lower-level board connects to the second solid-state switch. First terminal, third solid-state switch The first terminal is used as the output terminal of this stage;

[0010] All first solid-state switches Second terminal, all second solid-state switches The second terminal is connected to the high-voltage end of the load; all third solid-state switches The second terminal is grounded and connected to the low-voltage end of the load.

[0011] By controlling the switching timing, charging, positive polarity discharge, positive polarity truncation, negative polarity discharge, and negative polarity truncation are realized sequentially, and a bipolar square wave pulse is output.

[0012] Preferred charging sequence: Turn off all first solid-state switches Second solid-state switch Turn on the main switch With the third solid-state switch DC power supply via the first diode Second diode Energy storage capacitors for each stage of the unit circuit Parallel equalization charging: the subsequent stage circuit is charged in parallel with the previous stage, and the voltage of each capacitor is consistent.

[0013] Preferred sequence for positive discharge: Turn off the main switch All first solid-state switches Third solid-state switch Turn on all second solid-state switches Energy storage capacitors of each unit circuit. The series pulses are superimposed to output a positive high-voltage pulse to the load.

[0014] Preferred timing for positive polarity truncation: After the positive polarity discharge is completed, all third solid-state switches are turned on. This allows the load charge to pass through the third solid-state switch. Rapid discharge enables rapid pulse truncation.

[0015] Preferred sequence for negative polarity discharge: Turn off the main switch All second solid-state switches Third solid-state switch Turn on all first solid-state switches Energy storage capacitors of each unit circuit. The reverse series superposition outputs a negative polarity high voltage pulse to the load.

[0016] Preferred: The negative polarity truncation timing is as follows: after the negative polarity discharge ends, the charging state is entered. Taking advantage of the characteristic that the capacitor voltage cannot change abruptly, the negative potential of the load is quickly pulled to zero potential, thereby realizing the rapid truncation of the negative polarity pulse.

[0017] Preferably: the main switch First solid-state switch Second solid-state switch Third solid-state switch All of them are any one of insulated gate bipolar transistors, metal-oxide-semiconductor transistors, or gallium nitride high electron mobility transistors, to adapt to high frequency and high voltage working scenarios.

[0018] Preferably: the first diode Second diode All are fast recovery diodes, silicon carbide Schottky diodes, or ultra-fast recovery diodes to reduce reverse recovery losses during switching and increase the circuit operating frequency.

[0019] Preferred: Each energy storage capacitor in the stage unit circuit The capacitance values ​​are equal, and all are high-voltage non-inductive capacitors to ensure balanced charging voltage at each stage and reduce the impact of parasitic inductance on the pulse waveform.

[0020] Preferred: In the level unit circuit, For positive integers greater than or equal to 2, the number of stages in the extended unit circuit is... It can linearly increase the amplitude of the output pulse to meet the testing requirements of different voltage levels.

[0021] The beneficial effects of this invention are as follows: First, the bipolar square wave pulse power supply designed in this invention not only achieves a steep rise time and fast truncation, but also uses only 3 IGBTs and diodes per stage, while traditional bipolar all-solid-state Marx generators use 6 sets of IGBTs and diodes per stage. This reduces the use of 3 sets of IGBTs and diodes per stage, resulting in a reduction of 3n sets of IGBTs and diodes in an n-stage circuit, making the power supply more compact, reducing energy loss, and simplifying the control circuit. Second, the power supply uses diodes for isolation instead of resistors, which solves the problem of insufficient charging current for the energy storage capacitor. Third, when the energy storage capacitor discharges to the load in a series-superimposed voltage manner, the switch... It can be turned off by a control circuit, which can turn off the DC power supply. It is isolated from the discharge circuit; in addition, the output of unipolar or bipolar square wave pulses can be achieved by changing the timing of the solid-state switch trigger circuit, and the output pulse width and frequency of the pulse power supply can also be adjusted. Attached Figure Description

[0022] Figure 1 This is a circuit diagram of the bipolar square wave pulse of the present invention;

[0023] Figure 2 This is the switching control timing diagram of the present invention;

[0024] Figure 3 This describes the charging process of the bipolar square wave pulse circuit of the present invention.

[0025] Figure 4 This is a positive polarity pulse discharge process;

[0026] Figure 5 It is a positive polarity pulse truncated circuit;

[0027] Figure 6 This is a negative polarity pulse discharge process;

[0028] Figure 7 This is a negative polarity pulse truncated circuit;

[0029] Figure 8 This is a schematic diagram of the bipolar trapezoidal wave signal output by the present invention. Detailed Implementation

[0030] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0031] Specific implementation method one: Combining Figures 1-8This embodiment describes a high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source, including a DC power supply. DC power supply internal resistance r, main switch , Level unit circuits and loads;

[0032] The DC power supply The positive terminals are connected in series with the internal resistance r of the DC power supply and the main switch. Then, the DC power supply is connected to the input terminal of the first-stage unit circuit. The negative terminal is grounded;

[0033] Each unit circuit includes an energy storage capacitor. , First solid-state switch Second solid-state switch Third solid-state switch First diode Second diode , , of which The stage unit circuit also includes a third diode. For the first Level unit circuit :

[0034] The first diode The anode is connected to the first The output terminal of the stage unit circuit, the first diode The cathode is connected to the energy storage capacitor. The upper electrode plate, the first solid-state switch one end and the second diode The cathode;

[0035] The second diode The anode is connected to the main switch. The node between the input terminal of the first-stage unit circuit;

[0036] The energy storage capacitor The lower electrode plate is connected to the second solid-state switch. One end, the third solid-state switch one end and the first The input terminal of the stage unit circuit;

[0037] The first solid-state switch The other end is connected to the second solid-state switch After the other end is short-circuited, it is connected to one end of the load;

[0038] The third solid-state switch The other end is connected to the other end of the load, and the other end of the load is grounded;

[0039] For the Level unit circuit:

[0040] The first diode The anode is connected to the first The output terminal of the stage unit circuit, the first diode The cathode is connected to the energy storage capacitor. The upper electrode plate, the first solid-state switch one end and the third diode The cathode;

[0041] The third diode The anode is connected to the main switch. The node between the input terminal of the first-stage unit circuit;

[0042] The energy storage capacitor The lower electrode plate is connected to the second solid-state switch. One end, the third solid-state switch One end;

[0043] The first solid-state switch The other end is connected to the second solid-state switch After the other end is short-circuited, it is connected to one end of the load;

[0044] The third solid-state switch The other end is connected to the other end of the load, and the other end of the load is grounded;

[0045] The circuit controls the on / off sequence of each solid-state switch to realize the working process of charging, positive discharge and negative discharge, and outputs a bipolar square wave.

[0046] The working process of a high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source includes the following:

[0047] (1) Charging process: such as Figure 2 and Figure 3 As shown, during the period t0-t1, all first solid-state switches are turned off. Second solid-state switch Turn on the main switch With the third solid-state switch DC power supply via the first diode Second diode Energy storage capacitors for each stage of the unit circuit Parallel equalization charging: the subsequent stage circuit is charged in parallel with the previous stage, and the voltage of each capacitor is consistent.

[0048] (2) Positive polarity discharge process: such as Figure 2 and Figure 4 As shown, when the energy storage capacitor After being fully charged within the time interval t0-t1, the main switch is turned off within the time interval t2-t3. All first solid-state switches Third solid-state switch Turn on all second solid-state switches Energy storage capacitors of each unit circuit. The series pulses are superimposed to output a positive high-voltage pulse to the load.

[0049] (3) Positive polarity truncation process: such as Figure 2 and Figure 5 As shown, after time t3, the positive pulse discharge produces a tail, at which point the load is at a positive potential. After time t4, all third solid-state switches... Forming a discharge circuit with the load, the third solid-state switch Connected in series with the load, so that the load charge passes through a third solid-state switch. Rapid discharge causes the load voltage to drop quickly, achieving rapid pulse truncation.

[0050] (4) Negative polarity discharge process: such as Figure 2 and Figure 6 As shown, when the energy storage capacitor After fully charging within time t4-t5, turn off the main switch within time t6-t7. All second solid-state switches Third solid-state switch Turn on all first solid-state switches Energy storage capacitors of each unit circuit. Reverse series superposition, outputting negative polarity high voltage pulses to the load.

[0051] (5) Negative polarity truncation process: such as Figure 2 and Figure 7 As shown, after the negative discharge ends, the system enters the charging state. Utilizing the characteristic that capacitor voltage cannot change abruptly, the load's negative potential is quickly pulled to zero, achieving rapid tailing of the negative pulse. Specifically, after time t7, the negative pulse discharge produces a tail; at this time, the load is at a negative potential, and the energy storage capacitor... One end is grounded, and the other end is connected to the load at a negative potential. Then, within the time interval t7-t8, the circuit enters the charging loop state, and the DC power supply... Through the first diode Second diode and main switch Third solid-state switch For energy storage capacitors Charging, and at the same time due to the energy storage capacitor The potentials at both ends cannot change abruptly. The end with the negative potential quickly becomes zero potential, that is, the negative potential of the load is quickly changed to zero potential, thereby achieving rapid truncation of the negative polarity pulse.

[0052] like Figure 8 As shown, the waveform consists of alternating positive and negative pulses, featuring a steep rising edge, a stable flat top, and a fast truncation. The pulse amplitude, pulse width, and repetition frequency can be flexibly adjusted through the switching timing, which can simulate the bipolar transient overvoltage in the actual operation of high-voltage equipment and meet the diverse requirements of partial discharge testing for waveform parameters.

[0053] Specific Implementation Method Two: This implementation method provides a high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source, which can be widely applied in the field of high-voltage pulse electric field excitation and testing. Specifically, it can be used as a high-voltage pulse excitation source in the scenario of partial discharge detection of power equipment, providing adjustable high-voltage pulse signals for the detection of insulation defects in power equipment such as transformers, switchgear, and cables, simulating partial discharge pulses at the insulation defects of the equipment, and realizing the assessment and fault diagnosis of the insulation status of power equipment; it can also be applied in the field of non-thermal sterilization of liquid food, utilizing the non-thermal effect of the high-voltage pulse electric field to sterilize liquid foods such as egg liquid, fruit juice, and dairy products, achieving sterilization effect while preserving... It preserves the original nutrients and flavor of food; it can be applied to the performance testing of power insulation devices, applying high-voltage pulse excitation to high-voltage insulators, insulating bushings, and other power insulation devices to test their insulation tolerance, charge accumulation and release characteristics under high-voltage pulse conditions; it can also be applied to the field of biomedical cell electroporation research, achieving controllable electroporation of cell membranes by outputting high-voltage pulses with adjustable parameters, providing technical support for biomedical experiments such as cell transfection and drug delivery; it can also be used to test the charge characteristics, discharge laws, and dynamic impedance changes of various resistive-capacitive loads under high-voltage pulse action, providing experimental data and technical references for the research and development of related high-voltage pulse equipment.

[0054] In this embodiment, the parameters of the test source are listed in the table below:

[0055]

[0056] The power supply includes DC power module components, bipolar pulse main circuit core components, control timing module components, isolation drive module components, and overcurrent protection module auxiliary components.

[0057] I. DC Power Supply Module Components

[0058] The DC power supply is an adjustable high-voltage DC power supply with an output of 0-3kV and a rated output current of ≥5A. It meets the charging voltage requirements for +7.5kV / -7.5kV bipolar pulse output under a 3-level topology, while providing sufficient charging current for the energy storage capacitor. Its adjustable voltage characteristic adapts to test scenarios with different pulse amplitudes. The DC power supply is equipped with a 2Ω / 50W precision power resistor. This resistance limit the maximum current in the charging circuit, preventing overcurrent charging of the capacitor, and ensuring that the capacitor charges to ≥0.95 times the DC power supply voltage within 0.97ms, meeting the charging efficiency requirements under high-frequency pulses.

[0059] II. Core Components of the n-Level Bipolar Pulse Main Circuit

[0060] (a) Energy storage capacitor: Energy storage capacitor (i=1,2,…,n) all use CYEC CSG3000106J1160 capacitors, with four 3kV, 10μF capacitors connected in parallel to form a 3kV / 40μF capacitor bank. Under the conditions of a 1-20μs pulse width and a maximum pulse current of 2000A, the 40μF capacitance ensures a pulse drop of ≤20% at the top, guaranteeing a smooth square wave waveform. The 3kV withstand voltage matches the DC charging voltage, meeting high-voltage insulation requirements. These ceramic capacitors feature fast charging and discharging response and non-polarity, making them suitable for high-frequency switching conditions with bipolar pulses. Furthermore, connecting multiple capacitors in parallel enhances their high-current charging and discharging capabilities.

[0061] (ii) Solid-state switches (IGBT modules)

[0062] main switch First solid-state switch Second solid-state switch Third solid-state switch All modules used are ABB 5SNE0800E330100 high-power IGBT modules. The solid-state switch collector-emitter withstand voltage (VCES) is 3300V, higher than the 3kV DC charging voltage, with a safety insulation margin; the continuous collector current I... C =800A, peak current I CM =1600A, which can match the output requirements of this test source of 1000A single pulse current and 2000A peak-to-peak current; rise time t r =190ns, descent time t f With a switching speed of 340ns, it can guarantee a steep rate of change of pulse edge ≤200ns. Simultaneously, this module integrates an anti-parallel diode and a separate high-voltage diode, eliminating the need for additional isolation and freewheeling diodes, simplifying the circuit structure, reducing loop inductance, and its industrial-grade package allows direct embedding into the driver board, improving device integration.

[0063] (iii) Isolation diode

[0064] First diode Second diode The high-voltage diode integrated into the 5SNE0800E330100 IGBT module is selected, with a reverse breakdown voltage of 3300V and an average forward current of 800A. Using an integrated diode that matches the IGBT module solves the problem of insufficient charging current for the energy storage capacitor, ensuring balanced charging of multiple capacitor stages. Furthermore, because it is of the same specification as the IGBT, it avoids circuit failures caused by mismatched device parameters. Simultaneously, this diode is a high-voltage fast recovery type with a short reverse recovery time, adapting to the timing requirements of high-frequency (≤1000Hz) operation of high-voltage pulse power supplies.

[0065] III. Control Timing Module Components

[0066] The core of the control timing module uses the Altera Cyclone IV series EP4CE6F17C8N FPGA development board, which contains 179 I / O ports and can output ≥5 sets of high-precision synchronous control signals to meet the independent timing control requirements of 13 IGBTs in a 3-level topology. Equipped with a 50MHz crystal oscillator circuit, the control signal clock accuracy is high, achieving a switching synchronization accuracy of ≤100ns, ensuring the consistency of voltage superposition during multi-stage capacitor series discharge. Simultaneously, the development board supports in-system programming, allowing flexible adjustment of pulse width and frequency to achieve unipolar / bipolar square wave switching, matching the design requirements of high-voltage pulse power supplies for "multi-parameter adjustable and adaptable to multiple application scenarios." The integrated AD sampling interface can acquire loop current signals in real time, linking with the overcurrent protection module to meet the operational requirements of pulse power supplies for "fast overcurrent response and system safety."

[0067] IV. Isolation Driver Module Components

[0068] (I) IGBT Driver Board: The IGBT driver board selected is the Concept 1SD536F2-5SNA0800N330100 model, a dedicated driver board for the 5SNE0800E330100 IGBT module. This driver board can be directly embedded in the IGBT module, with a compact structure and reduced wiring inductance, which helps to improve the steepness of the pulse edge; the maximum output power is 5W, the drive current is 36A, and it can reliably drive high-power IGBTs to turn on and off quickly; the turn-on delay is 350ns, the turn-off delay is 450ns, the output rise time is 15ns, and the fall time is 20ns, with accurate timing response to ensure the synchronization of IGBT switching actions. At the same time, this driver board integrates overcurrent detection and soft turn-off functions, enabling the pulse power supply to have overcurrent protection and prevent device breakdown, and the maximum operating frequency reaches 18kHz, which is much higher than the maximum frequency of 1000Hz of this test source, without frequency bottleneck limitations.

[0069] (ii) Photoelectric conversion board

[0070] The optoelectronic conversion board uses the TX-JKDF1 fiber optic conversion board from Beijing Luomuyuan Company. This board converts one electrical signal into two fiber optic signals, achieving electrical isolation between the high-voltage main circuit and the low-voltage control circuit through fiber optic transmission, ensuring the transmission accuracy of the control signals. This board reduces system wiring, adapts to multi-channel control signal transmission requirements, and integrates two alarm signal input ports, allowing for overcurrent and overvoltage fault signals to achieve fault-linked alarm and protection. The transmission delay is ≤100ns, not affecting the synchronization of control signals and meeting the requirements for precise timing of pulse power supply control.

[0071] V. Auxiliary Components of Overcurrent Protection Module

[0072] The overcurrent protection module uses a Hall effect current sensor with a range of 0-2000A and a response time ≤1μs. It employs a non-contact Hall effect measurement method, does not interfere with the main circuit, has no energy loss, and is suitable for high-voltage, high-current operating conditions. The range covers the peak-to-peak value of the 2000A pulse current from this test source, offering high measurement accuracy (error ≤1%) and fast response speed. It can capture sudden overcurrents caused by load short circuits and breakdowns in real time, providing accurate current signals to the protection module. The protection relay is a 5kV high-voltage DC relay with a rated current of 10A, connected in series at the DC power supply output. When overcurrent protection is triggered, this relay immediately cuts off the DC power supply, preventing the fault from escalating and further enhancing the safety of equipment operation.

[0073] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source, characterized in that, Including DC power supply DC power supply internal resistance r, main switch , Level unit circuits and loads; The DC power supply The positive terminals are connected in series with the internal resistance r of the DC power supply and the main switch. Then, the DC power supply is connected to the input terminal of the first-stage unit circuit. The negative terminal is grounded; Each unit circuit includes an energy storage capacitor. , First solid-state switch Second solid-state switch Third solid-state switch First diode Second diode , , In a single channel of the same level unit, the first diode The anode serves as the input terminal of this stage, and the first diode... Cathode connected to energy storage capacitor The upper electrode plate, the first solid-state switch First terminal and second diode Cathode; Second diode The anodes are connected together to the main switch. Output terminal; energy storage capacitor The lower-level board connects to the second solid-state switch. First terminal, third solid-state switch The first terminal is used as the output terminal of this stage; All first solid-state switches Second terminal, all second solid-state switches The second terminal is connected to the high-voltage end of the load; all third solid-state switches The second terminal is grounded and connected to the low-voltage end of the load. By controlling the switching timing, charging, positive polarity discharge, positive polarity truncation, negative polarity discharge, and negative polarity truncation are realized sequentially, and a bipolar square wave pulse is output.

2. The high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source according to claim 1, characterized in that, The charging sequence is as follows: Turn off all first solid-state switches. Second solid-state switch Turn on the main switch With the third solid-state switch DC power supply via the first diode Second diode Energy storage capacitors for each stage of the unit circuit Parallel equalization charging: the subsequent stage circuit is charged in parallel with the previous stage, and the voltage of each capacitor is consistent.

3. The high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source according to claim 1, characterized in that, The positive discharge sequence is: turn off the main switch. All first solid-state switches Third solid-state switch Turn on all second solid-state switches Energy storage capacitors of each unit circuit. The series pulses are superimposed to output a positive high-voltage pulse to the load.

4. The high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source according to claim 3, characterized in that, The positive polarity truncation timing is as follows: After the positive polarity discharge is completed, all third solid-state switches are turned on. This allows the load charge to pass through the third solid-state switch. Rapid discharge enables rapid pulse truncation.

5. The high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source according to claim 1, characterized in that, The negative polarity discharge sequence is: turn off the main switch. All second solid-state switches Third solid-state switch Turn on all first solid-state switches Energy storage capacitors of each unit circuit. The reverse series superposition outputs a negative polarity high voltage pulse to the load.

6. The high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source according to claim 5, characterized in that, The negative polarity truncation timing sequence is as follows: after the negative polarity discharge ends, the charging state begins. Taking advantage of the characteristic that the capacitor voltage cannot change abruptly, the negative potential of the load is quickly pulled to zero potential, thus achieving rapid truncation of the negative polarity pulse.

7. The high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source according to claim 1, characterized in that, The main switch First solid-state switch Second solid-state switch Third solid-state switch All of them are any one of insulated gate bipolar transistors, metal-oxide-semiconductor transistors, or gallium nitride high electron mobility transistors.

8. The high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source according to claim 1, characterized in that, The first diode Second diode All are fast recovery diodes, silicon carbide Schottky diodes, or ultrafast recovery diodes.

9. The high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source according to claim 1, characterized in that, Each energy storage capacitor in the stage unit circuit The capacitance values ​​are equal, and all are high-voltage non-inductive capacitors.

10. A high-voltage, high-frequency, pulse waveform adjustable high-voltage partial discharge test source according to claim 1 or 9, characterized in that, In the level unit circuit, It is a positive integer greater than or equal to 2.

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