Nanosecond pulse high voltage power supply and control method

Abstract

A nanosecond pulse high-voltage power supply and control method, which adopts a pulse generating circuit arranged at the front end of the primary coil of a transformer, simplifies the structure of the high-voltage rear end, and makes the pulse power supply more stable and reliable; adopts different combinations of 4-way low-voltage pulse width modulation PWM drive control of two H-bridge inverter circuits to achieve arbitrary output of high-voltage pulse single positive polarity output, pulse single negative polarity output, and pulse AC output, avoids high-voltage discharge during high-voltage side switching, and improves reliability; can be integrated in a single-chip microcomputer or embedded in software to achieve control, making control more convenient, can realize digital control adjustment, has a wide adjustable range, and improves the control accuracy of pulse output peak voltage.

Description

Technical Field

[0001] The present invention relates to the technical field of pulse high-voltage power supplies, and in particular to a nanosecond pulse high-voltage power supply and a control method thereof. Background Art

[0002] Nanosecond pulse high voltage power supply belongs to special high voltage power supply equipment. Nanosecond pulse high voltage can be used to generate high voltage pulse discharge, and has a wide range of application prospects in air pollution control, water pollution control, material surface treatment, semiconductor material processing, etc. Nanoscale pulse high voltage discharge has many significant advantages. Short time scale, the time scale of nanosecond pulse discharge is very short, and the processing time of each pulse is less than 1 microsecond. This high-speed processing method makes nanosecond pulse discharge have significant advantages in occasions that require fast response and efficient processing. Rapid release of energy, nanosecond high voltage pulses can release extremely high energy in a very short time (nanosecond level), forming a high energy density electric field and plasma, and the voltage waveform of nanosecond pulse discharge has steep rising and falling edges, which makes the discharge process faster and more efficient. At the same time, the pulse width is narrow, and high voltage pulses can be applied in a short time, enhancing the reduced electric field (E / N) in the discharge area, and quickly generating a large number of highly active particles such as electrons. In the non-thermal equilibrium process of nanosecond pulse discharge, the single pulse discharge time is not enough to make the plasma undergo thermal conversion, so the entire discharge process is kept at room temperature or low temperature, effectively suppressing the possibility of transition from discharge to spark discharge, and maintaining the discharge in a more uniform and stable mode. At the same time, the environmentally friendly treatment process does not involve conventional chemical reagents in the nanosecond pulse discharge process.

[0003] In the engineering application of nanosecond pulse high-voltage power supply, the nanosecond pulse high-voltage power supply needs to design the appropriate pulse high-voltage output rising edge, pulse width, and falling edge to match the electrical parameters of the reactor. During use, it is necessary to change the pulse high-voltage output parameters such as polarity, peak voltage, repetition frequency, etc. to adapt to different applications or changes in working conditions to achieve precise matching and control. For example, in air pollution control, there are various types of harmful gases in air pollution, and the concentration of harmful gases is high or low. The gas flow rate to be treated is large or small, and the humidity is different. The insulation strength is different. Changing the repetition frequency of the nanosecond pulse high-voltage power supply can adapt to the different flow rates of air pollution control gases, and changing the peak voltage of the nanosecond pulse high-voltage power supply can adapt to the different insulation strengths of the gas. Changing the polarity of the output of the nanosecond pulse high-voltage power supply can adapt to harmful gases of different components and concentrations in air pollution. For example, positive polarity nanosecond pulse discharge can generate high-energy electrons and ultraviolet rays, which can decompose harmful substances (such as volatile organic compounds VOCs) in exhaust gas and convert them into harmless substances. Due to the characteristics of positive polarity nanosecond pulse discharge, streamer propagation can cover a longer distance, produce more branches and streamer channels, and thus form a larger reaction area. This large-area discharge channel provides more opportunities and space for the generation of ozone, promotes the generation of ozone, and reacts with harmful substances in the exhaust gas to further purify the exhaust gas. However, the gas breakdown strength of positive polarity nanosecond pulse discharge is lower than that of negative polarity nanosecond pulse discharge, and when the concentration of harmful gases is very small, ozone does not fully react with the concentration of harmful gases and is prone to exceed the standard. When the concentration of harmful gases is very small and the gas breakdown strength is low, negative polarity nanosecond pulse discharge output is more suitable. When the composition of harmful gases in atmospheric pollution is complex, you can choose to alternate between negative and positive polarity to form nanosecond pulse discharge AC output to improve the pollution treatment effect.

[0004] In the field of nanosecond pulse high-voltage power supply technology, the more advanced existing technologies are as follows:

[0005] Chinese invention patent CN116113132A discloses a power supply discharge system based on single and bipolar nanosecond pulses that can be converted. It solves the problem that traditional nanosecond pulse power supplies cannot simultaneously meet the output requirements of high repetition frequency, high voltage amplitude, fast rising edge, and single / bipolar pulse mode switching. The system includes a drive module, an IGBT inverter circuit, a filter input circuit, a ZVS resonant circuit, a pulse transformer, a magnetic compression circuit, a single and bipolar conversion module, and a bipolar pulse electrode; the IGBT inverter circuit is connected forward and reversely in sequence after receiving the IGBT inverter circuit control signal, and the filter input circuit inputs electric energy to the magnetic compression circuit after boosting the voltage through the IGBT inverter circuit, the ZVS resonant circuit, and the pulse transformer. The magnetic compression circuit shortens the pulse rising edge and pulse width and outputs high-voltage single / bipolar nanosecond pulses to the bipolar pulse electrode after passing through the single and bipolar conversion module to generate discharge. It can output high-voltage nanosecond single / bipolar pulses in a high repetition frequency working mode.

[0006] Chinese invention patent CN117375581A discloses a high-frequency, high-voltage pulse power supply module, including a mutually coupled HV input module, a current feedback module, a frequency feedback module and an HV output module; the current feedback module adopts high-frequency counting technology and Hall current acquisition technology to ensure efficient switching of high and low current output modes, and the frequency feedback module adopts MOSFET to construct a power switch module, which improves the switch control efficiency, effectively controls the pulse width, improves the sensitivity of the detector, and ensures the pulse output frequency and power stability of the HV output module.

[0007] As mentioned above, some of the existing technical solutions have proposed a technical solution for outputting high-voltage single / bipolar nanosecond pulses to bipolar pulse electrodes to generate discharge after passing through a single-bipolar conversion module, and some have announced a solution for efficient switching of high and low current output modes. On the one hand, these existing technologies basically adopt the technical design of setting a single-bipolar conversion module at the rear end of the transformer secondary coil, which makes the structure of the high-voltage rear end complicated, thereby affecting the stability and reliability of the pulse power supply. On the other hand, these existing technologies fail to provide specific and effective solutions for single-bipolar conversion. The effective control of the power supply that can be converted into single-bipolar nanosecond pulses is not involved at all. Summary of the invention

[0008] In view of the problems described in the background technology, the present invention proposes a technical solution of a nanosecond pulse high voltage power supply and a control method, the specific contents of which are as follows:

[0009] A circuit used in a nanosecond pulse high-voltage power supply includes a pulse output peak voltage regulating circuit, a pulse generating circuit, a pulse boosting circuit, a pulse energy storage circuit, a pulse rising edge control circuit, a pulse width control circuit and a pulse falling edge control circuit; the pulse output peak voltage regulating circuit controls the operating frequency of an H-bridge inverter circuit composed of semiconductor modules through two groups of pulse width modulation (PWM) drives, changes the voltage value of a high-frequency rectification and filtering circuit on the secondary side of a high-frequency transformer, and regulates and controls the changed pulse output peak voltage.

[0010] The pulse generating circuit is arranged at the front end of the primary coil of the pulse boosting circuit to control the repetition frequency of the pulse generation of the pulse high voltage power supply and change the polarity of the pulse high voltage output. The repetition frequency of the pulse generation is mainly controlled by the frequency signal of the pulse generating circuit. The pulse width modulation PWM drive frequency of the two H-bridge inverter circuits is controlled. Different combinations of the two groups of pulse width modulation PWM drives of the two H-bridge inverter circuits control the output polarity of the pulse high voltage power supply. The two groups of PWM drive cycles of the two H-bridge inverter circuits are the same. The auxiliary H-bridge inverter circuit PWM drive high level is after the main H-bridge inverter circuit PWM drive high level pulse width. Through different combinations, the pulse single positive polarity output, pulse single negative polarity output, and pulse AC output are controlled.

[0011] Different combinations of the two groups of pulse width modulation PWM drives of the two H-bridge inverter circuits control the output polarity of the pulse high-voltage power supply. PWM1 controls semiconductor modules VT1 and VT4, PWM2 controls semiconductor modules VT2 and VT3, the pulse high level of PWM3 controls semiconductor modules VT5 and VT7, and the pulse high level of PWM4 controls semiconductor modules VT6 and VT8. The pulse width modulation PWM1 is controlled to be completely closed, the pulse width modulation PWM2 changes periodically, the pulse width modulation PWM3 changes periodically, and the pulse width modulation PWM4 is completely closed. The PWM2 and PWM3 change periods are the same, and the pulse single positive polarity output; the pulse width modulation PWM1 is controlled to change periodically, the pulse width modulation PWM2 is completely closed, the pulse width modulation PWM3 is completely closed, and the pulse width modulation PWM4 changes periodically. The PWM1 and PWM4 change periods are the same, and the pulse single negative polarity output; the pulse width modulation PWM1 is controlled to change periodically, the pulse width modulation PWM2 changes periodically, the pulse width modulation PWM3 changes periodically, and the pulse width modulation PWM4 changes periodically, and the pulse AC output is performed. The phase difference between PWM1 and PWM2 is 178°, and the phase difference between PWM3 and PWM4 is 178°, so as to avoid symmetry imbalance.

[0012] The pulse rising edge control circuit includes a magnetic switch, and the adjustable parameters of the magnetic switch are controlled so that the functional relationship between the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, the maximum magnetic density Bm of the magnetic core and the voltage on the capacitor of the pulse energy storage circuit is closest to the following formula:

[0013]

[0014] Where: N is the number of turns of the magnetic switch, S is the cross-sectional area of ​​the magnetic core, Bm is the maximum magnetic flux density of the magnetic core, Uc is the voltage on the capacitor of the pulse energy storage circuit, and Tc is the duration of the voltage Uc on the capacitor Ca of the pulse energy storage circuit;

[0015] Control the rising edge to control the magnetic switch to saturate and conduct, quickly supplying power to the load. The magnetic switch saturation inductance can adjust the pulse rising edge.

[0016] The pulse falling edge control circuit includes a magnetic switch and a discharge resistor, and controls the adjustable parameters of the magnetic switch so that the functional relationship between the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, the maximum magnetic density Bm of the magnetic core and the voltage Up on the load is closest to the following formula:

[0017]

[0018] Where: N is the number of turns of the magnetic switch, S is the cross-sectional area of ​​the magnetic core, Bm is the maximum magnetic flux density of the magnetic core, Up is the voltage on the load, and Tp is the duration of the voltage Up on the load.

[0019] The magnetic switch is controlled to be saturated and turned on, and the electric energy stored in the load is released through the saturated inductance and discharge resistance of the magnetic switch, and quickly drops to zero, thereby realizing pulse width control.

[0020] The two H-bridge inverter circuits in the pulse generating circuit are one as the main circuit for pulse generating and the other as the auxiliary circuit for pulse generating.

[0021] The pulse boost circuit includes a pulse boost transformer. The low voltage pulse passes through the primary coil of the pulse transformer and is coupled through the magnetic core of the pulse transformer. The secondary coil of the pulse transformer outputs a high voltage pulse. The peak value of the high voltage pulse is between 10KV and 200KV.

[0022] The pulse energy storage circuit is composed of a plurality of capacitors connected in series and is used for storing the charge of the pulse current.

[0023] The pulse output peak voltage regulating circuit comprises an AC-DC conversion rectifying circuit, a filtering circuit, a high-frequency transformer and a high-frequency rectifying and filtering circuit.

[0024] The pulse rising edge control circuit includes a magnetic switch. When the charge of the capacitor Ca continues to accumulate, the voltage Uc of the capacitor Ca rises, and the volt-second product of the voltage Uc and the duration of Uc exceeds the product of the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, and the maximum magnetic density Bm of the magnetic core, the magnetic switch is saturated and turned on to quickly supply power to the load.

[0025] The pulse output peak voltage regulating circuit, pulse generating circuit, pulse boosting circuit, pulse energy storage circuit, pulse rising edge control circuit, pulse width control circuit and pulse falling edge control circuit all adopt high-frequency design to ensure the high-frequency performance and stability of the entire system.

[0026] The number of turns of the magnetic switch MZ2 of the falling edge control circuit is N, the product of the core cross-sectional area S and the maximum magnetic flux density Bm of the core is greater than or equal to the product of the load voltage Up and the Up duration Tp, and the inductance value after the magnetic switch is saturated and turned on can achieve a pulse voltage falling edge of less than 1us.

[0027] Compared with the prior art, the present invention has the following beneficial technical effects:

[0028] 1. A nanosecond pulse high-voltage power supply and control method abandons the technical design of setting a single-polarity and bipolarity conversion module at the rear end of the secondary coil of the transformer, and adopts a pulse generating circuit at the front end of the primary coil of the transformer, which greatly simplifies the structure of the high-voltage rear end and makes the pulse power supply more stable and reliable.

[0029] 2. A nanosecond pulse high-voltage power supply and control method, which uses two H-bridge inverter circuits to form a pulse generating circuit, and only uses different combinations of 4-way low-voltage pulse width modulation PWM drive control of the two H-bridge inverter circuits to achieve arbitrary output of high-voltage pulse single positive polarity output, pulse single negative polarity output, and pulse AC output, as well as pulse repetition frequency adjustment and control. The different combinations of 4-way low-voltage pulse width modulation PWM drive control remove the complex circuit structure and mechanical structure of different polarity outputs on the high-voltage side, reduce the complexity of the pulse voltage, and increase the life of the power supply and reliability; the real-time response of the output is greatly improved by using pulse width modulation PWM drive control, and the repetition frequency capability is greatly improved; high-voltage discharge during switching on the high-voltage side is avoided, and reliability is improved; it can be integrated in embedded software such as a single-chip microcomputer to achieve control, making control more convenient.

[0030] 3. A nanosecond pulse high-voltage power supply and control method for controlling the pulse output peak voltage adopts an H-bridge inverter circuit and a high-frequency transformer solution. By adjusting the pulse width modulation (PWM) drive frequency of the H-bridge inverter circuit, digital control adjustment can be achieved. A high-frequency transformer solution is adopted, which has a small size, high control frequency, and a wide adjustable range. Different frequencies correspond to different pulse output peak voltages, thereby improving the control accuracy of the pulse output peak voltage.

[0031] Nanosecond high-voltage pulse output, including rising edge control circuit, pulse width and falling edge control circuit, realizes pulse rising edge, pulse width and pulse falling edge control, and improves nanosecond power supply performance.

[0032] 4. A nanosecond pulse high-voltage power supply and control method with high-frequency, high-voltage, nanosecond pulse signal output maximizes the frequency and amplitude of the output pulse compared to the prior art, meeting the needs of high-precision scientific research and medical equipment.

[0033] 5. A nanosecond pulse high-voltage power supply and control method, which can control the pulse rising and falling edge times with high precision, and improve the accuracy and reliability of the pulse signal compared with the prior art.

[0034] 6. A nanosecond pulse high-voltage power supply and control method uses a pulse energy storage circuit composed of capacitors, which can efficiently store the charge of the pulse current, improving the energy utilization rate and working efficiency of the system compared with the existing technology.

[0035] 7. A nanosecond pulse high-voltage power supply and control method thereof adopts a pulse output peak voltage adjustment circuit composed of an AC-DC conversion rectifier circuit, a filter circuit, a high-frequency transformer, and a high-frequency rectifier and filter circuit. It can control and adjust the output pulse peak voltage in real time, which improves the flexibility and adaptability of the system compared with the existing technology.

[0036] 8. A nanosecond pulse high voltage power supply and control method The nanosecond pulse high voltage power supply adopts high reliability and long life components such as magnetic switches and discharge resistors, which improves the reliability and working life of the system compared with the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The invention is a circuit schematic diagram of a nanosecond pulse high voltage power supply and a control method.

[0038] Figure 2 The invention is a pulse single positive polarity output diagram of a nanosecond pulse high voltage power supply and a control method.

[0039] Figure 3 The invention is a pulse single negative polarity output diagram of a nanosecond pulse high voltage power supply and a control method.

[0040] Figure 4 The invention is a pulse AC output diagram of a nanosecond pulse high voltage power supply and a control method.

[0041] Figure 5 The invention relates to a transformer core BH curve diagram of a nanosecond pulse high voltage power supply and a control method.

[0042] Figure 6 The invention relates to a nanosecond pulse high voltage power supply and a control method. When the transformer-free core BH curve is reset in the same direction, the nanosecond pulse high voltage power supply Uc pulse AC output abnormal oscillation diagram is shown.

[0043] In the accompanying drawings: Ip is the current on the load, Uc is the voltage of the capacitor of the pulse energy storage circuit, Up is the voltage on the load, Time represents the time on the horizontal axis, Bm is the maximum magnetic flux density of the magnetic core, B represents the magnetic flux density, and H represents the magnetic field strength. DETAILED DESCRIPTION

[0044] A nanosecond pulse high-voltage power supply and control method adopts industrial frequency AC power supply, and mainly consists of a pulse output peak voltage adjustment circuit, a pulse generating circuit, a pulse boosting circuit, a pulse energy storage circuit, a pulse rising edge control circuit, and a pulse width and falling edge control circuit.

[0045] The pulse output peak voltage regulating circuit is mainly composed of an AC-DC conversion rectifier circuit, a filter circuit, an H-bridge inverter circuit composed of semiconductor modules, a high-frequency transformer, and a high-frequency rectifier and filter circuit. The operating frequency of the H-bridge inverter circuit composed of semiconductor modules is controlled by two sets of pulse width modulation PWM drives, the voltage value of the high-frequency rectifier and filter circuit on the secondary side of the high-frequency transformer is changed, and the changed pulse output peak voltage is regulated and controlled.

[0046] The pulse generation circuit includes two H-bridge inverter circuits, which are composed of semiconductor modules. One of the H-bridge inverter circuits is the main circuit for pulse generation, including two groups of pulse width modulation PWM drive control pulse width modulation PWM1 and pulse width modulation PWM2, and the other H-bridge inverter circuit is the auxiliary circuit for pulse generation, including two groups of pulse width modulation PWM drive control pulse width modulation PWM3 and pulse width modulation PWM4. The H-bridge of the pulse generation main circuit flows the main current during pulse generation, and the pulse power energy transfer is transmitted through the H-bridge inverter pulse generation main circuit. The H-bridge of the pulse generation auxiliary circuit is connected in series with a current limiting resistor, and the current flowing through is very small, which is mainly used to reset the magnetic core of the pulse transformer, prevent the magnetic core from saturation and stabilize the BH curve working point of the magnetic core of the pulse transformer. The current limiting resistor of the H-bridge of the pulse generation auxiliary circuit should meet the current requirement of resetting the magnetic core of the pulse boost transformer TR1. The current is used to generate the magnetic core reset magnetic field, and the intensity of the reset magnetic field is related to the BH characteristics of the specific magnetic core material.

[0047] The pulse generating circuit is mainly used to control the repetition frequency of the pulse generation of the pulse high voltage power supply. The repetition frequency of the pulse generation is controlled by the pulse width modulation PWM driving frequency of the two H-bridge inverter circuits. The output polarity of the pulse high voltage power supply changes and is controlled by different combinations of two groups of pulse width modulation PWM driving of the two H-bridge inverter circuits. Through different combinations, pulse single positive polarity output, pulse single negative polarity output, and pulse AC output can be controlled, as shown in Table 1 below.

[0048]

[0049] Table 1

[0050] The pulse energy storage circuit is mainly composed of one or more capacitors connected in series, which is used to store the charge of the pulse current. When the load is a capacitive load, the capacitance of the pulse energy storage circuit is greater than or equal to the load capacitance value.

[0051] The width Pw of the pulse width modulation PWM drive of the H-bridge of the pulse generating main circuit is related to the leakage inductance Ls of the pulse boost transformer, the transformation ratio N of the pulse boost transformer, and the capacitance Ca of the pulse energy storage circuit. The width Pw of the drive is greater than or equal to half of the resonant period of the product of the leakage inductance Ls of the pulse boost transformer, the square of the transformation ratio of the pulse boost transformer, and the capacitance Ca of the pulse energy storage circuit, that is, .

[0052] The pulse rising edge control circuit is mainly composed of a magnetic switch. The number of turns of the rising edge control magnetic switch coil is N, the cross-sectional area of ​​the magnetic switch core is S, and the maximum magnetic density of the magnetic switch core is Bm. The parameters of the rising edge control magnetic switch are related to the voltage Uc on the pulse energy storage circuit capacitor Ca. The time Tmax for the voltage Uc on the pulse energy storage circuit capacitor Cp to rise to the maximum peak voltage UcMax is equal to Therefore, the product of the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, and the maximum magnetic flux density Bm of the magnetic core should be greater than or equal to The voltage Uc on the capacitor Ca of the pulse energy storage circuit, the duration Tc of the voltage Uc, and the adjustable parameters of the rising edge control magnetic switch make the functional relationship between the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, the maximum magnetic density Bm of the magnetic core, and the voltage on the capacitor of the pulse energy storage circuit most approximate the following formula:

[0053]

[0054] That is, when the volt-second product of the voltage Uc of the pulse energy storage circuit capacitor and the duration Tc of the voltage Uc exceeds the product of the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, and the maximum magnetic density Bm of the magnetic core, the rising edge controls the magnetic switch to saturate and conduct, and quickly supplies power to the load. The saturated inductance of the magnetic switch can adjust the pulse rising edge.

[0055] The pulse width and falling edge control circuit is mainly composed of a magnetic switch and a discharge resistor. The voltage Up on the load, the duration of the voltage Up on the load Tp. The width controls the number of turns of the magnetic switch coil N, the cross-sectional area of ​​the magnetic switch core S, and the maximum magnetic flux density of the magnetic switch core Bm. The adjustable parameters of the magnetic switch are controlled so that the functional relationship between the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, the maximum magnetic flux density Bm of the magnetic core and the voltage Up on the load is closest to the following formula:

[0056]

[0057] That is, when the volt-second product of the load voltage Up and the duration of the voltage Up is greater than the product of the number of turns N of the width-controlled magnetic switch, the core cross-sectional area S, and the maximum magnetic density Bm of the core, the width-controlled magnetic switch is saturated and turned on, and the electric energy stored in the load is released through the saturated inductance and discharge resistance of the magnetic switch, and quickly drops to zero, realizing pulse width control. The saturated inductance and discharge resistance of the magnetic switch can adjust the falling edge of the pulse.

[0058] A specific embodiment: A nanosecond pulse high voltage power supply and control method, such as Figure 1 The nanosecond pulse high voltage power supply is powered by A, B, and C three-phase industrial frequency AC power supply.

[0059] Pulse output peak voltage adjustment circuit: The three-phase rectifier bridge DM1 completes the AC-DC conversion, the capacitor C1 filters the DC, and the semiconductor modules VT11, VT12, VT13, and VT14 form an H-bridge inverter circuit. The H-bridge inverter circuit contains two sets of drive control pulse width modulation PWMA and pulse width modulation PWMB. The drive control pulse width modulation PWMA and pulse width modulation PWMB control the H-bridge inverter circuit to convert DC into high-frequency AC. The high-frequency AC is isolated and converted by the high-frequency transformer TR2, rectified by the DM2 high-frequency rectifier bridge, filtered by the C2 capacitor, and outputs the DC voltage Udc. By adjusting the operating frequency of the two sets of drive control pulse width modulation PWMA and pulse width modulation PWMB of the H-bridge inverter circuit, the DC voltage Udc can be changed, thereby adjusting the control change of the pulse output peak voltage. To output the control pulse output peak voltage to the peak voltage target value, the frequency of the two sets of drive control pulse width modulation PWMA and pulse width modulation PWMB of the H-bridge inverter circuit can be increased or decreased.

[0060] Pulse generation circuit: powered by the DC Udc output by the pulse output peak voltage regulation circuit, including two H-bridge inverter circuits. One of the H-bridge inverter circuits is the main circuit for pulse generation, which is composed of semiconductor modules VT1, VT2, VT3, and VT4, and also includes two groups of pulse width modulation PWM drive control pulse width modulation PWM1 and pulse width modulation PWM2. The main circuit H-bridge of the pulse generation flows the main current when the pulse occurs, and the pulse power energy transfer is transmitted through the H-bridge inverter pulse generation main circuit. The other H-bridge inverter circuit is the auxiliary circuit for pulse generation, which is composed of semiconductor modules VT5, VT6, VT7, and VT8, and also includes two groups of pulse width modulation PWM drive control pulse width modulation PWM3 and pulse width modulation PWM4. The pulse generation auxiliary circuit H-bridge is also connected in series with limited current R1 and R2, which are mainly used to reset the magnetic core of the pulse transformer to prevent the magnetic core from saturation and stabilize the working point of the BH curve of the magnetic core of the pulse transformer. The current flowing through is very small, and the H-bridge semiconductor module can use a small current device. The secondary coil of the pulse transformer outputs a high voltage pulse. Semiconductor modules VT1, VT2, VT3, and VT4 form the pulse generation main circuit H bridge, which is directly connected to the primary coil of the pulse boost transformer TR1. Semiconductor modules VT5, VT6, VT7, and VT8 form the pulse generation auxiliary circuit H bridge current limiting circuits R1 and R2, which are connected to the primary coil of the pulse boost transformer TR1. The pulse generation circuit is mainly used to control the repetition frequency of the pulse generation of the pulse high-voltage power supply. The repetition frequency of the pulse generation is controlled by the pulse width modulation PWM drive frequency of the two H-bridge inverter circuits. The output polarity change of the pulse high-voltage power supply is controlled by different combinations of the two groups of pulse width modulation PWM drives of the two H-bridge inverter circuits. Through different combinations, the pulse single positive polarity output, pulse single negative polarity output, and pulse AC output can be controlled.

[0061] Pulse single positive polarity output control, see Figure 2 : The drive controls the pulse width modulation PWM1 to output a low level, so that the semiconductor modules VT1 and VT4 remain completely turned off. The drive controls the pulse width modulation PWM4 to output a low level, so that the semiconductor modules VT6 and VT8 remain completely turned off. The drive controls the pulse width modulation PWM2 to change according to the preset value of the pulse repetition frequency. The change cycle of the pulse width modulation PWM2 is the inverse of the preset value of the pulse repetition frequency. The pulse width Pw of the pulse width modulation PWM2 is greater than or equal to half of the resonant cycle of the product of the leakage inductance Ls of the pulse boost transformer, the square of the pulse boost transformer ratio and the pulse energy storage circuit capacitance Ca, that is, . The drive controls the pulse width modulation PWM2 to control the semiconductor modules VT2 and VT3 to turn on and off according to the pulse width modulation PWM2 cycle and pulse width, and generates a large pulse current in the primary coil of the pulse boost transformer TR1 according to the preset value of the pulse repetition frequency, and outputs a positive polarity high-voltage pulse in the secondary coil of the pulse boost transformer TR1. The drive controls the pulse width modulation PWM3. With the same change cycle of the pulse width modulation PWM2, the pulse high level of the pulse width modulation PWM3 is completely staggered in time with the pulse high level of the pulse width modulation PWM2. The pulse high level of the pulse width modulation PWM3 is after the pulse high level of the pulse width modulation PWM2. The semiconductor modules VT5 and VT7 are controlled to turn on and off according to the pulse width modulation PWM3 cycle and pulse width. A reverse reset current is generated through the H-bridge current limiting resistors R1 and R2, so that the working point of the BH curve of the magnetic core of the pulse boost transformer TR1 is restored to another quadrant. Prevent the magnetic core of the pulse boost transformer TR1 from continuously working in the same quadrant, resulting in the reduction or saturation of the working area of ​​the BH curve of the magnetic core, resulting in the inability to conduct pulse energy normally. See the BH curve. Figure 5 .

[0062] Pulse single negative polarity output control, see Figure 3 :Drive and control the pulse width modulation PWM2 to output a low level, so that the semiconductor modules VT2 and VT3 remain completely turned off. Drive and control the pulse width modulation PWM3 to output a low level, so that the semiconductor modules VT5 and VT7 remain completely turned off. Drive and control the pulse width modulation PWM1, change according to the preset value of the pulse repetition frequency, the change cycle of the pulse width modulation PWM1 is the inverse of the preset value of the pulse repetition frequency, and the pulse width Pw of the pulse width modulation PWM1 is greater than or equal to half of the resonant period of the product of the leakage inductance Ls of the pulse boost transformer, the square of the pulse boost transformer ratio and the pulse energy storage circuit capacitance Ca, that is, . The drive controls the pulse width modulation PWM1 to control the semiconductor modules VT1 and VT4 to turn on and off according to the pulse width modulation PWM1 cycle and pulse width, and generates a large pulse current in the primary coil of the pulse boost transformer TR1 according to the preset value of the pulse repetition frequency, and outputs a negative polarity high-voltage pulse in the secondary coil of the pulse boost transformer TR1. The drive controls the pulse width modulation PWM4. With the same change cycle of the pulse width modulation PWM1, the pulse high level of the pulse width modulation PWM4 is completely staggered in time with the pulse high level of the pulse width modulation PWM1. The pulse high level of the pulse width modulation PWM4 is after the pulse high level of the pulse width modulation PWM1. The semiconductor modules VT6 and VT8 are controlled to turn on and off according to the pulse width modulation PWM4 cycle and pulse width. A reverse reset current is generated through the H-bridge current limiting resistors R1 and R2, so that the working point of the BH curve of the magnetic core of the pulse boost transformer TR1 is restored to another quadrant. Prevent the magnetic core of the pulse boost transformer TR1 from continuously working in the same quadrant, resulting in the reduction or saturation of the working area of ​​the BH curve of the magnetic core, resulting in the inability to conduct pulse energy normally. See the BH curve. Figure 5.

[0063] Pulse AC output control, see Figure 4 : PWM2 controls the semiconductor modules VT2 and VT3 to turn on and off according to the pulse width modulation PWM2 cycle and pulse width, which is used to trigger the control to generate positive pulse high voltage, corresponding to the positive half-wave of the pulse current Ip, the positive half-wave of the energy storage capacitor pulse high voltage Uc, and the positive half-wave of the load pulse high voltage Up; after the PWM2 triggers the positive pulse, the high level of the pulse of PWM3 controls the semiconductor modules VT5 and VT7, and turns on and off according to the pulse width modulation PWM3 cycle and pulse width, and generates a reset current in the same direction as the PWM2 control through the H-bridge current limiting resistors R1 and R2, so as to reduce the back and forth oscillation of the residual pulse energy when the pulse generator stops working due to the discontinuous AC change of the current. Figure 6 As shown, at the same time, the pulse core BH curve is kept in the +Bm interval, so that when a negative pulse is generated next, the working interval of the pulse core is from the +Bm to the -Bm interval. PWM1 controls the semiconductor modules VT1 and VT4 to turn on and off according to the pulse width modulation PWM1 cycle and pulse width, which is used to trigger and control the generation of negative pulse high voltage, corresponding to the negative half-wave of the pulse current Ip, the negative half-wave of the energy storage capacitor pulse high voltage Uc, and the negative half-wave of the load pulse high voltage Up. After PWM1 triggers the generation of a positive pulse, the high level of the pulse of PWM4 controls the semiconductor modules VT6 and VT8 to turn on and off according to the pulse width modulation PWM4 cycle and pulse width, and generates a reset current in the same direction as the PWM1 control through the H-bridge current limiting resistors R1 and R2, thereby reducing the back-and-forth oscillation of the residual pulse energy when the pulse generator stops working due to the discontinuous AC change of the current, as shown in FIG. Figure 6 As shown, the pulse core BH curve is kept in the -Bm range, so that when a positive pulse is generated next, the working range of the pulse core is from the -Bm to the +Bm range.

[0064] Transformer core BH curve for pulse AC output, see Figure 5 : The driving control pulse width modulation PWM1 and pulse width modulation PWM2 change according to the preset value of the pulse repetition frequency. The change period of the pulse width modulation PWM1 and pulse width modulation PWM2 is the inverse of the preset value of the pulse repetition frequency. The driving control pulse width modulation PWM1 has the same period as the driving control pulse width modulation PWM2, and the phase difference is 178 degrees. The pulse width Pw of the pulse width modulation PWM1 and pulse width modulation PWM2 is greater than or equal to half of the resonant period of the product of the leakage inductance Ls of the pulse boost transformer, the square of the pulse boost transformer ratio and the capacitance Ca of the pulse energy storage circuit, that is, . The drive controls the pulse width modulation PWM1 to control the semiconductor modules VT1 and VT4 to turn on and off according to the pulse width modulation PWM1 cycle and pulse width, and outputs negative polarity high-voltage pulses in the secondary coil of the pulse step-up transformer TR1. The drive controls the pulse width modulation PWM2 to control the semiconductor modules VT2 and VT3 to turn on and off according to the pulse width modulation PWM2 cycle and pulse width, and outputs positive polarity high-voltage pulses in the secondary coil of the pulse step-up transformer TR1. The phase difference between the pulse width modulation PWM1 and the pulse width modulation PWM2 is 178 degrees, and the pulse AC output is formed by alternating control. The drive controls the pulse width modulation PWM3, with the same change cycle of the pulse width modulation PWM1, and the drive controls the pulse width modulation PWM4, with the same change cycle of the pulse width modulation PWM2. The pulse high level time of the drive controls the pulse width modulation PWM3 and the pulse width modulation PWM1 is completely staggered with the drive controls the pulse width modulation PWM4 and the pulse width modulation PWM2. The high level pulse of PWM3 controls the semiconductor modules VT5 and VT7 to turn on and off according to the cycle and pulse width of PWM3. The high level pulse of PWM4 controls the semiconductor modules VT6 and VT8 to turn on and off according to the cycle and pulse width of PWM4. A reset current in the same direction is generated through the H-bridge current limiting resistors R1 and R2. Due to the discontinuous alternating current change of the pulse generator current, when it stops working, the residual pulse energy oscillates back and forth. Figure 6 As shown, the BH curve operating point of the core of the pulse boost transformer TR1 is unstable. The same-direction reset current can keep the BH curve operating point of the core of the pulse boost transformer TR1 stable in the current quadrant, ensuring the normal operation of the next reverse pulse. When the next reverse pulse works, it moves from the opposite BH curve quadrant to another quadrant, while increasing the utilization rate of the core.

[0065] The current limiting resistors R1 and R2 of the H-bridge of the auxiliary circuit for pulse generation should meet the current requirements of the core of the reset pulse boost transformer TR1.

[0066] Pulse boost circuit: mainly composed of pulse boost transformer TR1, Ls is the leakage inductance of pulse boost transformer TR1. The low voltage pulse of the pulse generating circuit passes through the primary coil of the pulse transformer, coupled through the magnetic core of the pulse transformer, and the secondary coil of the pulse transformer outputs a high voltage pulse. The secondary coil of the pulse transformer is connected in parallel with the energy storage capacitor Ca.

[0067] The pulse energy storage circuit is mainly composed of a capacitor Ca, and the capacitor Ca can be composed of one or more capacitors connected in series and parallel.

[0068] The pulse rising edge control circuit is mainly composed of the magnetic switch MZ1. When the charge of the capacitor Ca continues to accumulate, the voltage Uc of the capacitor Ca rises, and the volt-second product of the voltage Uc and the duration of Uc exceeds the product of the number of turns N of the magnetic switch MZ1, the cross-sectional area S of the magnetic core, and the maximum magnetic density Bm of the magnetic core, the magnetic switch MZ1 is saturated and turned on, and power is quickly supplied to the load FZ. According to the load characteristics of FZ, the appropriate inductance value after the magnetic switch MZ1 is saturated and turned on is designed, so that the pulse voltage rising edge is less than 1us, and the pulse voltage rising edge time is at the nanosecond level.

[0069] The pulse width and falling edge control circuit is mainly composed of a magnetic switch MZ2 and a discharge resistor Ra. When the volt-second product of the voltage Up on the load FZ and the duration of the voltage Up is greater than the product of the number of turns N of the magnetic switch MZ2, the cross-sectional area S of the magnetic core, and the maximum magnetic flux density Bm of the magnetic core, the magnetic switch MZ2 is saturated and turned on, and the electric energy stored on the load FZ is released through the saturated inductance and discharge resistor of the magnetic switch MZ2, and quickly drops to zero. By designing the number of turns N of the magnetic switch MZ2, the cross-sectional area S of the magnetic core, and the product of the maximum magnetic flux density Bm of the magnetic core to a suitable value, the width of the pulse voltage on the load FZ can be controlled to be less than 1us, and the pulse voltage width time can be adjusted to the nanosecond level. The saturated inductance value of the magnetic switch MZ2 and the discharge resistor Ra can adjust the falling edge of the pulse.

[0070] When the load FZ is a capacitive load, the capacitance Ca of the pulse energy storage circuit is greater than or equal to the capacitance Cz of the load FZ.

[0071] Special statement: The "embodiment" and the like described in this specification refer to the specific features, elements or characteristics described in conjunction with the embodiment included in the embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not limit the specific reference to the same embodiment. In other words, when describing a specific feature, element or characteristic in conjunction with any embodiment, it is claimed that such feature, element or characteristic is implemented in conjunction with other embodiments and is included in the scope of the claims for protection of the present invention; The embodiment describes the present invention with reference to multiple explanatory embodiments of the logical architecture and ideas of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can design many other modifications and implementation methods within the framework of the technical solution of the present invention, and can make various non-essential modifications and improvements to the key points of the technical solution. For those skilled in the art, other uses will also be obvious, and non-substantial changes or replacements that can be easily thought of for implementation will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A nanosecond pulse high-voltage power supply, the circuit used includes a pulse output peak voltage adjustment circuit, a pulse generation circuit, a pulse boost circuit, a pulse energy storage circuit, a pulse rising edge control circuit, a pulse width control circuit and a pulse falling edge control circuit; characterized in that: The pulse output peak voltage regulation circuit controls the operating frequency of the H-bridge inverter circuit composed of semiconductor modules through two sets of pulse width modulation PWM drives, thereby changing the voltage value of the high-frequency rectification and filtering circuit on the secondary side of the high-frequency transformer, and finally regulating the pulse output peak voltage; The pulse generating circuit is arranged at the front end of the primary coil of the pulse boosting circuit to control the repetition frequency of the pulse generation of the pulse high voltage power supply and change the polarity of the pulse high voltage output. The repetition frequency of the pulse generation is controlled by the frequency of the driving pulse generating circuit of the two H-bridge inverter circuits PWM. Different combinations of the two groups of PWM drives of the two H-bridge inverter circuits control the output polarity of the pulse high voltage power supply. The two groups of PWM drive cycles of the two H-bridge inverter circuits are the same. The high level of the auxiliary H-bridge inverter circuit PWM drive is after the high level pulse width of the main H-bridge inverter circuit PWM drive. Through different combinations, the pulse single positive polarity output, the pulse single negative polarity output, and the pulse AC output are controlled.

2. A nanosecond pulse high voltage power supply according to claim 1, characterized in that: The two groups of pulse width modulation PWM drives of the two H-bridge inverter circuits control the output polarity of the pulse high voltage power supply. The pulse width modulation PWM1 controls the semiconductor modules VT1 and VT4. The pulse width modulation PWM2 controls the semiconductor modules VT2 and VT3. The pulse high level of the pulse width modulation PWM3 controls the semiconductor modules VT5 and VT7. The pulse high level of pulse width modulation PWM4 controls semiconductor modules VT6 and VT8, controls pulse width modulation PWM1 to be completely closed, pulse width modulation PWM2 to change periodically, pulse width modulation PWM3 to change periodically, pulse width modulation PWM4 to be completely closed, PWM2 and PWM3 to have the same periodic changes, and pulse single positive polarity output; controls pulse width modulation PWM1 to change periodically, pulse width modulation PWM2 to be completely closed, pulse width modulation PWM3 to be completely closed, pulse width modulation PWM4 to change periodically, PWM1 and PWM4 to have the same periodic changes, and pulse single negative polarity output; controls pulse width modulation PWM1 to change periodically, pulse width modulation PWM2 to change periodically, pulse width modulation PWM3 to change periodically, and pulse width modulation PWM4 to change periodically, and pulse AC output, and the phase difference between PWM1 and PWM2 is 178°, and the phase difference between PWM3 and PWM4 is 178°, so as to avoid symmetry imbalance.

3. A nanosecond pulse high voltage power supply according to claim 1, characterized in that: The pulse rising edge control circuit includes a magnetic switch, and the adjustable parameters of the magnetic switch are controlled so that the functional relationship between the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, the maximum magnetic density Bm of the magnetic core and the voltage on the capacitor of the pulse energy storage circuit is closest to the following formula: ； Where: N is the number of turns of the magnetic switch, S is the cross-sectional area of ​​the magnetic core, Bm is the maximum magnetic flux density of the magnetic core, Uc is the voltage on the capacitor of the pulse energy storage circuit, and Tc is the duration of the voltage Uc on the capacitor Ca of the pulse energy storage circuit; Control the rising edge to control the saturation conduction of the magnetic switch, quickly supply power to the load, and the saturation inductance of the magnetic switch can adjust the pulse rising edge; The pulse falling edge control circuit includes a magnetic switch and a discharge resistor, and controls the adjustable parameters of the magnetic switch so that the functional relationship between the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, the maximum magnetic density Bm of the magnetic core and the voltage Up on the load is closest to the following formula: ； Where: N is the number of turns of the magnetic switch, S is the cross-sectional area of ​​the magnetic core, Bm is the maximum magnetic flux density of the magnetic core, Up is the voltage on the load, and Tp is the duration of the voltage Up on the load; The magnetic switch is controlled to be saturated and turned on, and the electric energy stored in the load is released through the saturated inductance and discharge resistance of the magnetic switch, and quickly drops to zero, thereby realizing pulse width control.

4. A nanosecond pulse high voltage power supply according to claim 1, characterized in that: The two H-bridge inverter circuits in the pulse generating circuit are one as the main circuit for pulse generating and the other as the auxiliary circuit for pulse generating.

5. The nanosecond pulse high voltage power supply according to claim 1, characterized in that: The pulse boost circuit includes a pulse boost transformer. The low voltage pulse passes through the primary coil of the pulse transformer and is coupled through the magnetic core of the pulse transformer. The secondary coil of the pulse transformer outputs a high voltage pulse. The peak value of the high voltage pulse is between 10KV and 200KV.

6. A nanosecond pulse high voltage power supply according to claim 1, characterized in that: The pulse energy storage circuit is composed of a plurality of capacitors connected in series and is used for storing the charge of the pulse current.

7. The nanosecond pulse high voltage power supply according to claim 1, characterized in that: The pulse output peak voltage regulating circuit comprises an AC-DC conversion rectifying circuit, a filtering circuit, a high-frequency transformer and a high-frequency rectifying and filtering circuit.

8. The nanosecond pulse high voltage power supply according to claim 1, characterized in that: The pulse rising edge control circuit includes a magnetic switch. When the charge of the capacitor Ca continues to accumulate, the voltage Uc of the capacitor Ca rises, and the volt-second product of the voltage Uc and the duration of Uc exceeds the product of the number of turns N of the magnetic switch, the cross-sectional area S of the magnetic core, and the maximum magnetic density Bm of the magnetic core, the magnetic switch is saturated and turned on to quickly supply power to the load.

9. The nanosecond pulse high voltage power supply according to claim 1, characterized in that: The pulse output peak voltage regulating circuit, pulse generating circuit, pulse boosting circuit, pulse energy storage circuit, pulse rising edge control circuit, pulse width control circuit and pulse falling edge control circuit all adopt high-frequency design to ensure the high-frequency performance and stability of the entire system.

10. The nanosecond pulse high voltage power supply according to claim 1, characterized in that: When the number of turns of the magnetic switch MZ2 of the falling edge control circuit is N, the product of the core cross-sectional area S and the core maximum magnetic density Bm is greater than or equal to the product of the load voltage Up and the Up duration Tp, the inductance value after the magnetic switch is saturated and turned on can achieve a pulse voltage falling edge of less than 1us.

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