Direct-current high-voltage superposed nanosecond pulse power supply and control method

Abstract

The invention discloses a direct-current high-voltage superposition nanosecond pulse power supply and a control method, which realize a direct-current high-voltage superposition function and superpose a high-voltage direct-current voltage and a nanosecond pulse high-voltage voltage together to form a new voltage waveform. The problems that the pulse width is not easy to adjust, the requirement for driving isolation is high, and the occupied space is large in Bloom Line line stacking are solved, and the stacked voltage waveform can meet the requirements of some specific application occasions such as plasma physical experiments and material scientific research. By adopting a novel PWM algorithm, a Boost algorithm and a Flyback algorithm, accurate digital control is realized, output voltage and output time are adjusted in real time, a high-efficiency and high-reliability direct-current high-voltage superposed nanosecond pulse power supply is realized, and the direct-current high-voltage superposed nanosecond pulse power supply can be widely applied to occasions needing high-voltage direct-current voltage and nanosecond pulse high-voltage voltage and has wide application prospects. The air purifier is particularly suitable for dedusting and deodorizing polluted gas purifiers.

Description

Technical Field

[0001] The invention relates to pulse technology, and in particular to a direct current high voltage superimposed nanosecond pulse power supply and a control method. Background Art

[0002] Nanosecond pulse high voltage power supply is a special high voltage power supply equipment. Nanosecond pulse high voltage can be used to generate high voltage pulse discharge, and has broad application prospects in air pollution control, water pollution control, material surface treatment, semiconductor material processing, etc. Nanosecond pulse high voltage discharge has many significant advantages. The voltage waveform of nanosecond pulse discharge has steep rising and falling edges, which can release extremely high energy in a very short time (nanosecond level), instantly form a high-intensity electric field, and ionize to form a plasma containing high-density free radicals, positive and negative ions, which has great advantages in occasions that require fast response and efficient processing. The single duration scale is short, and the time scale of nanosecond pulse discharge is very short. The processing time of each pulse is less than 1 microsecond. It has the characteristics of ultra-high instantaneous energy and very low average energy, and the repetition frequency of nanosecond pulse discharge can be accurately controlled as needed, which makes the discharge process more efficient and energy-saving.

[0003] Although nanosecond pulse high-voltage power supplies have the above advantages, they only generate nanosecond pulse discharges, and the average output voltage value is low, which limits their application scope and application effects.

[0004] In the field of air pollution control, odor and smell control, nanosecond pulsed high-voltage power supplies instantly form a high-intensity electric field in the reactor, ionize to form a plasma containing high-density free radicals, positive and negative ions, decompose the odor and smell molecules in the gas, and achieve the purpose of removing odor and smell control. However, in the field of air pollution control, odor and smell control, particulate pollutants often also exist in the polluted gas, such as fine dust, fine droplets containing pollutants, droplets, etc. Although nanosecond pulse discharge can make these particulate pollutants charged, the average voltage value of its output is low, and the voltage cannot be continuously output and cannot drive the charged dust to move to the dust collecting electrode, so it cannot be captured. To capture these particulate pollutants in the gas, another set of equipment for capturing particulate matter is needed, such as adding dust removal and demisting devices. In the field of air pollution control, odor and smell control, how to integrate particulate pollutants with odor and smell control and reduce the floor space of the device is a difficult problem.

[0005] In the field of air pollution control and dust control, commonly used environmental protection devices are bag filters and electrostatic precipitators. The running resistance of electrostatic precipitators is at least 5 times lower than that of bag filters, and the running energy consumption is low, which has significant technical advantages. However, the fine dust capture effect of bag filters is better than that of electrostatic precipitators. In many occasions, they are replaced by bags. Electrostatic precipitators need to improve the capture efficiency of fine dust. Electrostatic precipitators generally use DC power supply. The density of electrons and ions generated by high-voltage DC power supply is low, and fine dust is not easy to charge and difficult to capture. Increasing the voltage of high-voltage DC power supply can increase the density of electrons and ions, but with the increase of DC voltage, the electric field of electrostatic precipitators becomes very unstable. The high average electric field strength will directly lead to local breakdown and short circuit of the electric field, and lose the dust removal effect. In recent years, there have also been studies on adding pulse power supply to electrostatic precipitators based on DC, but the pulse width of pulse power supply is between tens of microseconds and milliseconds. The pulse voltage width is too wide, and it is still easy to cause high-voltage breakdown and short circuit, and lose the dust removal effect. To meet the emission standards, the electrostatic precipitator needs to increase the number of electric fields, and the electric fields are cascaded and filtered step by step, which leads to a huge size of the electrostatic precipitator and high operating costs. If the electrostatic precipitator can use nanosecond pulse high-voltage power to instantly form a high-intensity electric field in the precipitator, generate high-density electrons and ions, quickly complete the charging of fine dust, and then drive the charged dust to move to the dust collecting electrode through DC voltage to improve the capture efficiency of fine dust, it will greatly improve the performance of the electrostatic precipitator, reduce the size, reduce operating energy consumption, and enhance the application value of the electrostatic precipitator in the field of air pollution control and dust control.

[0006] As mentioned above, there are also studies on existing technologies, among which the more representative technologies are: Chinese invention patent CN118174697B, a fully solid-state stacked Blumlein line pulse generator, discloses a fully solid-state stacked Blumlein line pulse generator, relates to the field of pulse power technology, and includes a signal generation module, a laser diode, a beam splitter, a photoelectric conversion circuit, a common mode inductor, a pulse forming circuit module, a load and a power supply system; the output end of the signal generation module is connected to the input end of the laser diode, the output end of the laser diode is connected to the input end of the beam splitter, the output end of the beam splitter is connected to the photoelectric conversion circuit, and the beam splitter evenly divides the laser light and transmits it to the photoelectric conversion circuit corresponding to each pulse forming circuit module through an optical fiber, triggering the pulse forming circuit module to discharge, and obtaining the final high voltage pulse on the load. The present invention realizes driving high-voltage isolation power supply and voltage superposition, and effectively reduces the mass and volume of the fully solid-state stacked Blumlein line, promotes the fully solid-state stacked Blumlein line pulse generator to develop towards practicality, and solves the high-voltage isolation problem of the stacked Blumlein line driving power supply.

[0007] Chinese invention patent CN118523755B pulse output method, device, source meter and storage medium discloses a pulse output method, device, source meter and storage medium, which can realize the charging of positive output capacitor group and negative output capacitor group through energy detection unit and energy storage control unit, complete energy storage, and under the control of main control unit, make output adjustment unit realize instantaneous output and complete high energy pulse signal output. The embodiment of the present application no longer needs to use high voltage power supply, which can greatly reduce cost, power consumption and safety risk.

[0008] These existing technologies that can form high-voltage pulses basically adopt the technical route of Blumlein line, and the existing technologies of the technical route of Blumlein line almost all have the following defects: 1. Pulse width is not easy to adjust: After the design of the traditional Blumlein line is completed, its pulse width is basically fixed, which is difficult to flexibly adjust according to different application requirements, limiting its application in some scenarios with diverse requirements for pulse width.

[0009] Difficulty in selecting switches: Unlike Marx circuits, the switch and load of the Blumlein line are not on the same side, so a step-by-step breakdown method cannot be adopted, which makes it difficult to select switches. For example, stacked Blumlein lines often use photoconductive switches as discharge switches, but the life of photoconductive switches is affected by voltage, current and the intensity of the triggering laser, and the overall life is not long.

[0010] 2. High requirements for driver isolation: When low-cost commercial switches such as IGBT switches are selected as discharge switches, there is a problem of driver isolation. If isolation is not done, the IGBT switch will be damaged. Although cascade transformers can be used to achieve isolated power supply for the driver, cascade transformers will increase the size of the system, which is not in line with the development trend of pulse power technology.

[0011] 3. Complex structural design and wiring: Its dual transmission line structure and related component layout make the structural design and wiring of the entire system relatively complex. In the actual production and installation process, higher technical requirements and more sophisticated operations are required to ensure the consistency of the parameters of the two transmission lines and the good matching between the components, otherwise it may affect the transmission efficiency and quality of the pulse.

[0012] 4. Strict requirements for load matching: In order to achieve efficient energy transmission and obtain ideal pulse output, the Blumlein line has strict requirements for load matching. If the load impedance does not match the characteristic impedance of the transmission line, it will cause pulse reflection, which will not only reduce the pulse power obtained on the load, but also may generate excessive voltage on the transmission line, damaging the equipment.

[0013] 5. Large space occupation: Compared with some single transmission line structures or other simple pulse generating circuits, the dual transmission line structure of the Blumlein line and related supporting components usually require a larger space, which may be limited in some application scenarios with compact space requirements, such as miniaturized electronic devices or portable instruments, and is not conducive to system integration and miniaturization design.

[0014] 6. Electromagnetic compatibility issues: During the pulse generation and transmission process, the Blumlein line will generate a strong electromagnetic field, which may cause electromagnetic interference to the surrounding electronic equipment or circuits, affecting their normal operation. At the same time, its own performance may also be affected by the external electromagnetic field. Therefore, when designing and using it, it is necessary to consider the electromagnetic compatibility issue and take corresponding shielding and filtering measures, which increases the complexity and cost of the system.

[0015] Therefore, in the technical field, there is an urgent need to develop a high-voltage pulse power supply that overcomes the above defects for use in fields such as air purification. Summary of the invention

[0016] In view of the problems described in the background technology, the present application proposes a technical solution of a DC high-voltage superimposed nanosecond pulse power supply and a control method, which realizes the DC high-voltage superposition function, superimposes the high-voltage DC voltage and the nanosecond pulse high-voltage voltage together to form a new voltage waveform, and overcomes the problems of the pulse width being difficult to adjust, the high requirements for drive isolation, and the large space occupation existing in the stacking of Blumlein lines. By adopting improved PWM algorithms, Boost algorithms and Flyback algorithms, precise digital control is achieved, and the output voltage and output time are adjusted in real time, thereby realizing a high-efficiency and high-reliability DC high-voltage superimposed nanosecond pulse power supply, which can be widely used in occasions requiring high-voltage DC voltage and nanosecond pulse high-voltage voltage, and is particularly suitable for use in polluted gas purifiers and motor group electrostatic precipitators.

[0017] A DC high voltage superimposed nanosecond pulse power supply is composed of an AC-DC conversion circuit, a high voltage DC circuit, and a nanosecond pulse high voltage circuit; the high voltage DC circuit can output DC high voltage, and the nanosecond pulse high voltage circuit outputs nanosecond pulse high voltage. The output end of the high voltage DC circuit is connected via a current limiting resistor, and the nanosecond high voltage pulse output end is connected to a high voltage coupling capacitor via a pulse isolation transformer. The two work together to form an output in which DC high voltage and nanosecond pulse high voltage are superimposed on the reactor.

[0018] The AC-DC conversion circuit uses an improved PWM algorithm to achieve the conversion of AC voltage to DC voltage. Its DC voltage is calculated according to the following formula: Vdc=(1 / 2)*Vm*(1+sin(ωt))*(1+k*sin(2ωt)) Where: Vdc is the DC voltage, Vm is the maximum value of the AC voltage, ω is the angular frequency of the AC voltage, t is the time, and k is the modulation coefficient.

[0019] The capacitance of the high-voltage coupling capacitor is greater than or equal to 5 times the capacitance of the reactor capacitor; the nanosecond pulse high-voltage circuit is composed of a pulse DC power supply, a pulse generator, a high-voltage pulse energy storage capacitor, a magnetic compression circuit, and a pulse isolation transformer. The pulse isolation transformer ratio range is: 1, 2, 3; the high-voltage pulse energy storage capacitor should satisfy the following formula:

[0020] Cs is the high-voltage pulse energy storage capacitor, Nc is the transformation ratio of the pulse isolation transformer (indicating that the transformation ratio is selected from one of the three numbers 1, 2, and 3), and Cz is the load capacitance.

[0021] The magnetic compression circuit is composed of a magnetic switch, which converts the microsecond pulses generated by the pulse generator into nanosecond pulses. The magnetic switch parameters satisfy the following formula: ; N is the number of turns of the magnetic switch coil, S is the cross-sectional area S of the magnetic switch core, △Bm is the magnetic density of the magnetic switch core, Pulse1 is the voltage on the high-voltage pulse energy storage capacitor, and Tc is the duration of voltage Pulse1.

[0022] The pulse generator is composed of a fully controlled semiconductor switch, an RCD protection circuit, a DC energy storage capacitor, and a pulse boost transformer, and is used to generate microsecond pulses; the capacity of the DC energy storage capacitor satisfies the following formula: ; Ce is the DC energy storage capacitor, Ns is the transformation ratio of the pulse boost transformer, Cs is the high-voltage pulse energy storage capacitor, Nc is the transformation ratio of the pulse isolation transformer, and Cz is the load capacitor.

[0023] The AC-DC conversion circuit converts three-phase industrial frequency AC power into a DC power supply, and the DC power supply simultaneously supplies power to the high-voltage DC circuit and the nanosecond pulse high-voltage circuit.

[0024] The high-voltage DC circuit is composed of a high-frequency H-bridge inverter, a resonant capacitor, a resonant inductor, a high-frequency step-up transformer, and a high-frequency high-voltage rectifier circuit. The frequency of the high-frequency H-bridge inverter is controlled by two PWM drives to control the output voltage of the high-voltage DC circuit. The output voltage of the high-voltage DC circuit is greater than or equal to 1.2 times the corona inception voltage value of the reactor.

[0025] The nanosecond pulse high-voltage circuit outputs a peak voltage of the pulse high voltage, controls the frequency of the high-frequency fully-controlled H-bridge inverter in the pulse DC power supply through two PWM drives, and changes the DC voltage value of the pulse DC power supply for control and regulation.

[0026] The repetition frequency of the pulse high voltage output by the nanosecond pulse high voltage circuit is adjusted by the frequency of the semiconductor full-control switch in the PWM drive control pulse generator, and satisfies the following formula when applied to air pollution purification: ; L is the total length of the reactor in m, V is the gas flow rate in m / s during air pollution purification, and F is the repetition frequency in HZ.

[0027] The high-voltage DC circuit adopts an improved Boost algorithm to boost the DC voltage to a high-voltage DC voltage. The calculation formula of the high-voltage DC voltage is: Vhv=Vdc / (1-D)*(1+α*Vdc); Where: Vhv is the high voltage DC voltage, Vdc is the DC voltage, D is the duty cycle, and α is the boost coefficient.

[0028] The nanosecond pulse high voltage circuit adopts an improved Flyback algorithm to convert the DC voltage into a nanosecond pulse high voltage voltage. The calculation formula of the nanosecond pulse high voltage voltage is: Vp=(Vdc*N) / (1-D)*(1+β*Vdc); Where: Vp is the nanosecond pulse high voltage, Vdc is the DC voltage, N is the turns ratio of the transformer, D is the duty cycle, and β is the pulse coefficient.

[0029] The calculation formula of the current limiting resistor is: Rx=Vhv / Ihv*(1+γ*Vhv); Where: Rx is the current limiting resistor, Vhv is the high voltage DC voltage, Ihv is the high voltage DC current, and γ is the current limiting coefficient.

[0030] The turns ratio calculation formula of the pulse isolation transformer is: N=Vp / Vhv*(1+δ*Vp); Where: N is the turns ratio of the pulse isolation transformer, Vp is the nanosecond pulse high voltage voltage, Vhv is the high voltage DC voltage, and δ is the pulse isolation coefficient.

[0031] The output of the superposition of the DC high voltage and the nanosecond pulse high voltage, the superposition voltage is calculated as follows: Vtotal=Vhv+Vp*(1+ε*Vhv); Where: Vtotal is the superposition voltage, Vhv is the high voltage DC voltage, Vp is the nanosecond pulse high voltage voltage, and ε is the superposition coefficient.

[0032] Compared with the prior art, the beneficial technical effects of the present invention are: 1. A DC high-voltage superimposed nanosecond pulse power supply and control method, which uses an improved PWM algorithm and can more accurately control the output of DC voltage, overcoming the defect of traditional PWM algorithm in converting AC voltage to DC voltage by simply converting based on a fixed duty cycle and other methods; A DC high-voltage superimposed nanosecond pulse power supply and control method applied to the field of air pollution control odor and peculiar smell control can realize the integration of two sets of devices for particulate pollutant control and odor and peculiar smell control into one, thereby reducing the cost of environmental protection equipment, reducing the demand for environmental protection equipment sites, and reducing operating energy consumption.

[0033] 2. A DC high-voltage superimposed nanosecond pulse power supply and control method improves voltage conversion efficiency: By adopting improved PWM algorithm, Boost algorithm and Flyback algorithm, high-efficiency voltage conversion and superposition can be achieved, reducing energy loss in the voltage conversion process, thereby improving voltage conversion efficiency. This high-efficiency voltage conversion technology can reduce circuit heat generation and improve circuit reliability and life.

[0034] 3. A DC high-voltage superimposed nanosecond pulse power supply and control method, which can realize the superposition of high-voltage DC voltage and nanosecond pulse high-voltage voltage to form a new voltage waveform, increase the flexibility of the voltage waveform, and can adjust the output voltage and output time in real time to maintain the stability of the voltage. This control technology can improve the stability of the voltage and reduce the voltage fluctuation and noise to meet the needs of specific applications. The flexibility of this voltage waveform can adapt the circuit to different applications, such as plasma physics experiments, material science research, etc.

[0035] 4. A DC high-voltage superimposed nanosecond pulse power supply and control method, which can adjust the output voltage and output time in real time to meet the needs of different applications by adopting a full set of digital algorithms. This control technology can improve the intelligence of the circuit, reduce the failure rate and maintenance cost of the circuit, improve the reliability of the circuit, reduce the failure rate and maintenance cost of the circuit, reduce the loss of the circuit, and improve the reliability and life of the circuit.

[0036] 5. A DC high-voltage superimposed nanosecond pulse power supply and control method, applied to the field of air pollution electrostatic dust treatment, can improve the capture efficiency of fine dust in the electrostatic precipitator without changing the mechanical structure of the electric field of the electrostatic precipitator, and improve the overall environmental protection dust treatment performance of the electrostatic precipitator. At the same time, it can reduce the operating energy consumption of the electrostatic precipitator, reduce the number of electric fields of the electrostatic precipitator, reduce the cost of environmental protection devices, and reduce the demand for environmental protection device sites.

[0037] 6. A DC high voltage superimposed nanosecond pulse power supply and control method. The DC high voltage, nanosecond pulse high voltage, and pulse repetition frequency are all controlled by PWM drive pulses of fully controlled semiconductor switches, and digital precise control, adjustment and optimization can be achieved according to working conditions.

[0038] 7. A DC high voltage superimposed nanosecond pulse power supply and control method. The DC high voltage has a low operating voltage and uses nanosecond pulse high voltage to instantly form a high-intensity electric field to generate high-density electrons and ions to quickly charge the dust, which can improve the fine dust capture efficiency of the electrostatic precipitator. At the same time, compared with the high-voltage continuous DC power supply mode, it can effectively reduce the operating energy consumption, avoid the electrostatic precipitator from breaking down and short-circuiting due to continuous high average voltage, and improve the stability of the environmental protection device.

[0039] 8. A DC high-voltage superimposed nanosecond pulse power supply and control method. The pulse compression circuit is realized by a magnetic switch, has a high repetition frequency, and can work continuously and uninterruptedly under high-voltage pulse high repetition frequency.

[0040] 9. A DC high-voltage superimposed nanosecond pulse power supply and control method, which uses fully controlled semiconductor switching devices with high adjustment accuracy. When the reactor high-voltage breakdown short circuit occurs, the high-voltage output can be quickly shut down through the fully controlled semiconductor switch to quickly protect the power supply from short circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a schematic diagram of a DC high voltage superimposed nanosecond pulse power supply and a control method.

[0042] Figure 2 The invention discloses an output waveform diagram of a DC high voltage superimposed nanosecond pulse power supply and a control method thereof.

[0043] Figure 3 The invention discloses a nanosecond pulse high voltage circuit waveform diagram of a DC high voltage superimposed nanosecond pulse power supply and a control method.

[0044] Figure 4 The present invention is a comparison diagram of a DC high voltage superimposed nanosecond pulse high voltage output waveform and a DC high voltage output waveform of a DC high voltage superimposed nanosecond pulse power supply and a control method.

[0045] Figure 5 The invention discloses a direct current high voltage superimposed nanosecond pulse power supply and a control method applied to an existing particle removal / defogging device and a odor removal device system schematic.

[0046] Figure 6 The invention discloses a DC high voltage superimposed nanosecond pulse power supply and a control method applied to a DC high voltage superimposed nanosecond pulse integrated environmental protection device schematic diagram.

[0047] Figure 7The invention relates to a DC high voltage superimposed nanosecond pulse power supply and a control method applied to an array diagram of 6×530 electric fields configured in an electrostatic precipitator of a 1000MW coal-fired power generation unit.

[0048] In the figure: Cs is a high-voltage pulse energy storage capacitor, MZ21 is a magnetic compression circuit, TR23 is a pulse isolation transformer, V21~V24 are semiconductor switches that constitute a high-frequency H-bridge inverter, Cb is a resonant capacitor, Lb is a resonant inductor, TR21 is a high-frequency step-up transformer, D21~D24 are diodes that constitute a high-frequency rectifier circuit, C22 is a filter capacitor, L21 is a current limiting inductor, V25 is a semiconductor switch, D25, R11, C24 are corresponding components that constitute an RCD protection circuit, Ce is a DC energy storage capacitor, TR22 is a pulse step-up transformer, DP1 is a nanosecond pulse voltage, DC11 is a high-voltage DC circuit control Control DC output, Pulse1 is the microsecond pulse voltage output after being stepped up by the pulse step-up transformer TR22 in the pulse generator, Pulse2 is the nanosecond pulse voltage output controlled by the nanosecond pulse high-voltage circuit, ESP1 and ESP2 are electrostatic precipitators, A1, A2, A3, A4, A5, B1, B2, B3, B4, B5, C1, C2, C3, C4 and C5 are electric fields, C1 is a filter capacitor, DC1 is a DC power supply, Time (ms) is the horizontal axis with the time unit in milliseconds, and 11, 12, 13, 14, 15 and 16 are the access points of the PWM drive control and regulation AC-DC conversion circuit. DETAILED DESCRIPTION

[0049] A DC high voltage superimposed nanosecond pulse power supply and control method, mainly composed of an AC-DC conversion circuit, a high voltage DC circuit, and a nanosecond pulse high voltage circuit. The high voltage DC circuit outputs DC high voltage, and the nanosecond pulse high voltage circuit outputs nanosecond pulse high voltage. One end of the high voltage DC output is grounded, and the other end of the high voltage DC output is connected to a reactor via a current limiting resistor. One end of the high voltage pulse output is grounded, and the other end of the high voltage pulse output is connected to a reactor via a pulse isolation transformer and a high voltage coupling capacitor. The two form a DC high voltage superimposed nanosecond pulse high voltage on the reactor.

[0050] The AC-DC conversion circuit has a three-phase industrial frequency AC input power supply. The three-phase industrial frequency AC power is rectified by a three-phase rectifier bridge and converted into a DC power supply after filtering. The DC power supply simultaneously supplies power for the high-voltage DC circuit and the nanosecond pulse high-voltage circuit.

[0051] Generally, the PWM (pulse width modulation) algorithm is an algorithm used to control voltage conversion. Its basic principle is to adjust the output voltage by controlling the switching time of the voltage converter. The specific implementation steps are as follows: determine the frequency and duty cycle of PWM, generate a PWM signal, input the PWM signal to the control end of the voltage converter, and the voltage converter controls the output voltage according to the duty cycle of the PWM signal.

[0052] For example, assume that the frequency of PWM is 100kHz and the duty cycle is 50%. Then the period of PWM signal is 10μs, the high level time is 5μs, and the low level time is 5μs. The voltage converter controls the output voltage according to the duty cycle of PWM signal, and the average value of output voltage is 50% of input voltage. This algorithm is not accurate enough, and it is necessary to improve the calculation method and the PWM algorithm of AC-DC conversion circuit to realize the conversion of AC voltage to DC voltage. The DC voltage is calculated according to the following formula: Vdc=(1 / 2)*Vm*(1+sin(ωt))*(1+k*sin(2ωt)); Where: Vdc is the DC voltage, Vm is the maximum value of the AC voltage, ω is the angular frequency of the AC voltage, t is the time, and k is the modulation coefficient.

[0053] As shown in the improved PWM algorithm principle analysis of the AC-DC conversion circuit, Vm is the maximum value of the AC voltage. In the AC voltage expression, it determines the amplitude range of the AC voltage. In this conversion formula, it is the basic amplitude parameter for DC voltage calculation. Because the output of DC voltage is related to the amplitude of the AC input voltage, the larger the AC voltage amplitude, the larger the converted DC voltage will be when other parameters remain unchanged.

[0054] The origin of the 1 / 2 coefficient: In the case of ideal half-wave rectification, the average value of the rectified AC voltage is 1 / π of the peak value of the AC voltage, and in the case of full-wave rectification it is 2 / π. The 1 / 2 here is a proportional coefficient in the process of converting AC voltage to DC voltage, taking into account other factors in the circuit (such as filtering, switching loss, duty cycle, etc.).

[0055] The existence of sin(ωt) and ω (angular frequency) indicates that the DC voltage output is related to the instantaneous value of the AC input voltage. Angular frequency determines how fast the AC voltage changes, and its existence means that the DC voltage output will change as the AC voltage frequency changes.

[0056] k is the modulation coefficient, which is used to adjust the part of the DC voltage output related to the second harmonic of the AC input voltage. sin(ωt) is the second harmonic component of the AC voltage. In the improved AC-DC conversion circuit PWM algorithm, the consideration of the second harmonic component may be to more accurately control the output of the DC voltage. By adjusting the value, the part of the DC voltage output related to the second harmonic can be changed, thereby achieving more flexible voltage control. The amplitude, frequency, and second harmonic of the AC voltage are comprehensively considered, and the converted DC voltage is accurately calculated through the combination of these parameters.

[0057] Rated power P of AC-DC conversion circuitDC1 , satisfying the following formula: ; P DC1 Rated power of AC-DC conversion circuit, P DC11 is the rated power of the high voltage DC circuit, P DC21 Rated power of pulse DC power supply.

[0058] The high-voltage DC circuit is mainly composed of a high-frequency H-bridge inverter, a resonant capacitor, a resonant inductor, a high-frequency step-up transformer, and a high-frequency high-voltage rectifier circuit. The high-voltage DC circuit controls the frequency of the high-frequency H-bridge inverter through two PWM drives to control the size of the high-voltage DC circuit. One end of the high-voltage DC output is grounded, and the other end of the high-voltage DC output is connected to the reactor through a current-limiting resistor.

[0059] The calculation formula of the current limiting resistor is: Rx=Vhv / Ihv*(1+γ*Vhv); Where: Rx is the current limiting resistor, Vhv is the high voltage DC voltage, Ihv is the high voltage DC current, and γ is the current limiting coefficient.

[0060] The high-frequency H-bridge inverter composed of fully controlled semiconductor switches in the high-voltage DC circuit has high regulation accuracy, and when the reactor high-voltage breakdown short circuit occurs, compared with the thyristor (silicon controlled) semi-controlled semiconductor switch device, the high-frequency H-bridge inverter output can be quickly turned off through the fully controlled semiconductor switch, the high-voltage DC voltage output can be turned off, and the high-voltage power supply can be quickly short-circuited. The fully controlled semiconductor switch is usually IGBT, MOSFET, etc.

[0061] The high-voltage DC circuit outputs a continuous DC high voltage on the reactor, generates a stable electric field, forms a basic DC corona discharge, and drives the charged particles in the gas to move along the electric field until they are captured by the dust collecting grounding electrode. The output voltage of the high-voltage DC circuit should be greater than or equal to 1.2 times the corona inception voltage of the reactor: ; Udc is the output voltage of the high-voltage DC circuit, and Uzs is the corona inception voltage value of the reactor, which is the corresponding starting voltage value when the reactor changes from zero current to current appearance under DC power supply.

[0062] In order to achieve precise control of high-voltage DC on the load, the operating frequency of the high-frequency H-bridge inverter in the high-voltage DC circuit should be increased, and the resonant capacitor value should be selected reasonably and should not be too large. At the same time, in order to reduce the switching loss of the semiconductor switch of the high-frequency H-bridge inverter and achieve zero current shutdown, the resonant capacitor Ca capacitance and resonant inductor La are selected according to the PWM drive pulse width control requirements. The resonant capacitor Ca capacitance and resonant inductor La satisfy the following formula: ; ; Ca is the resonant capacitor, La is the resonant inductor or the leakage inductance of the high-frequency step-up transformer, Na is the transformation ratio of the high-frequency step-up transformer, Cz is the load capacitor, and Pwd is the PWM drive pulse width of the high-frequency H-bridge inverter in the high-voltage DC circuit.

[0063] The resonant current of the high voltage DC circuit satisfies the following formula: ; Where: Ca is the resonant capacitor, La is the resonant inductor or the leakage inductance of the high-frequency step-up transformer, Na is the transformation ratio of the high-frequency step-up transformer, Cz is the load capacitance, P E is the rated output power of the high voltage DC circuit, U E Output rated voltage for high voltage DC circuit, i m At the maximum frequency f max The peak resonant current of the high-frequency H-bridge inverter, f max is the maximum operating frequency of the high-frequency H-bridge inverter, Ts is equal to It is half of the resonant period of the high-frequency H-bridge inverter in the high-voltage DC circuit.

[0064] The nanosecond pulse high-voltage circuit is mainly composed of a pulse DC power supply, a pulse generator, a high-voltage pulse energy storage capacitor, a magnetic compression circuit, and a pulse isolation transformer.

[0065] The turns ratio calculation formula of the pulse isolation transformer is: N=Vp / Vhv*(1+δ*Vp); Where: N is the turns ratio of the pulse isolation transformer, Vp is the nanosecond pulse high voltage voltage, Vhv is the high voltage DC voltage, and δ is the pulse isolation coefficient.

[0066] The pulse DC power supply is mainly composed of a high-frequency H-bridge inverter, a resonant capacitor, a resonant inductor, a high-frequency step-up transformer, a high-frequency rectifier circuit, a filter capacitor, a current-limiting inductor, and a diode. The pulse generator is composed of a semiconductor switch, an RCD protection circuit, a DC energy storage capacitor, and a pulse step-up transformer. The peak voltage of the nanosecond pulse high voltage is controlled by two PWM drives to control the frequency of the high-frequency H-bridge inverter in the pulse DC power supply, thereby changing the DC voltage value of the pulse DC power supply. The repetition frequency of the nanosecond pulse high voltage is controlled by one PWM drive to control the frequency of the semiconductor switch in the pulse generator.

[0067] The high-frequency H-bridge inverter composed of fully controlled semiconductor switches in the pulsed DC power supply has high peak voltage regulation accuracy of nanosecond pulse high voltage, and when the reactor high voltage breaks down and short-circuits, compared with the thyristor (silicon controlled) semi-controlled semiconductor switch device, the high-frequency H-bridge inverter output can be quickly shut down through the fully controlled semiconductor switch, shutting down the peak voltage output of the nanosecond pulse high voltage, and quickly short-circuiting the high-voltage power supply. The fully controlled semiconductor switch is usually IGBT, MOSFET, etc.

[0068] One end of the high-voltage pulse output is grounded, and the other end is connected to the reactor via a high-voltage coupling capacitor. The nanosecond pulse high-voltage circuit outputs nanosecond pulse high voltage at a repetition frequency on the reactor. The rising edge of the nanosecond pulse high voltage is less than or equal to 300ns, the pulse width is less than 1us, and the peak voltage can be adjusted. The nanosecond pulse high voltage is superimposed on the DC voltage generated by the high-voltage DC circuit through a high-voltage coupling capacitor. Within 1us, a pulse high-voltage electric field is quickly formed to ionize the gas passing through the reactor with high intensity, forming high-concentration charged ions and free radicals in the gas, which react electrochemically with odor and odor molecules to eliminate odor and odor in the gas.

[0069] In order to realize the superposition of DC high voltage nanosecond pulse power supply, the nanosecond high voltage pulse output is connected to the reactor through the high voltage coupling capacitor. The function of the high voltage coupling capacitor is to realize the isolation of the nanosecond pulse high voltage circuit and the DC high voltage. Without the high voltage coupling capacitor, the DC high voltage will cause the core saturation of the pulse isolation transformer in the nanosecond pulse high voltage circuit, and the DC high voltage will be short-circuited by the pulse isolation transformer coil. The high voltage coupling capacitor needs to select a suitable capacitance value. If it is too small, it will affect the output of the nanosecond pulse high voltage. The high voltage coupling capacitor Cc should satisfy the following formula: ; Where: Cc is the high voltage coupling capacitor, Cz is the load capacitor.

[0070] The pulse isolation transformer and the high-voltage coupling capacitor together realize the isolation of the DC high voltage to avoid the influence of the high-voltage DC circuit on the nanosecond pulse high-voltage circuit. The transformation ratio Nc of the pulse isolation transformer is less than or equal to 3, and the leakage inductance is less than 0.5uH. The transformation ratio and leakage inductance of the pulse isolation transformer will affect the rising edge of the nanosecond pulse high-voltage output.

[0071] The magnetic compression circuit is mainly composed of a magnetic switch. The main function of the magnetic compression circuit is to quickly release the charge in the high-voltage pulse energy storage capacitor after the magnetic switch is saturated, and convert the microsecond high-voltage pulse of the pulse generator into a nanosecond high-voltage pulse.

[0072] The magnetic compression circuit formed by the magnetic switch is realized by the principle of magnetic core saturation, with a high repetition frequency, and can work continuously and uninterruptedly under the high repetition frequency of high-voltage pulses. Another self-breakdown switch and Blumlein transmission line solution, the working life of the self-breakdown switch device is limited by the number of device breakdowns, and the performance recovery takes a long time, and it cannot work continuously and uninterruptedly under the high repetition frequency of high-voltage pulses.

[0073] The main parameters of the magnetic switch are the number of coil turns N, the cross-sectional area of ​​the magnetic switch core S, and the magnetic density △Bm of the magnetic switch core. The magnetic switch parameters are related to the voltage Pulse1 on the high-voltage pulse energy storage capacitor Cs. The time Tmax for the voltage Pulse1 on the high-voltage pulse energy storage capacitor Cs to rise to the maximum peak voltage Pulse1Max 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 magnetic flux density △Bm of the magnetic core should be greater than or equal to The voltage Pulse1 on the capacitor Cs of the pulse energy storage circuit, the duration Tc of the voltage Pulse1, and the magnetic switch parameters: ; High-voltage pulse energy storage capacitors are mainly used to store the charge generated by the pulse generator. The parameters are configured according to the load capacitance. The high-voltage pulse energy storage capacitor Cs should satisfy the following formula: ; Cs is the high-voltage pulse energy storage capacitor, Nc is the transformation ratio of the pulse isolation transformer, and Cz is the load capacitance.

[0074] The main function of the pulse generator is to generate microsecond pulses through a PWM drive to control the semiconductor switch, control the repetition frequency of the pulse generation through the working frequency of the semiconductor switch, and generate high-voltage pulses through a pulse boost transformer.

[0075] The repetition frequency of the pulse generation should satisfy the following formula: ; L is the total length of the reactor in m, V is the gas flow rate in m / s, and F is the repetition frequency in HZ.

[0076] Generally, the Boost algorithm is an algorithm for boosting voltage. Its basic principle is to adjust the output voltage by controlling the switching time of the voltage converter. The specific implementation steps are: determine the frequency and duty cycle of Boost, generate a Boost signal, input the Boost signal to the control end of the voltage converter, and the voltage converter controls the output voltage according to the duty cycle of the Boost signal; for example, assume that the frequency of Boost is 100kHz and the duty cycle is 80%. Then the period of the Boost signal is 10μs, the high level time is 8μs, and the low level time is 2μs. The voltage converter controls the output voltage according to the duty cycle of the Boost signal, and the average value of the output voltage is 1.8 times the input voltage. This algorithm has a large error with reality, so it must be improved. The high-voltage DC circuit uses an improved Boost algorithm to boost the DC voltage to a high-voltage DC voltage. The calculation formula for the high-voltage DC voltage is: Vhv=Vdc / (1-D)*(1+α*Vdc); Where: Vhv is the high voltage DC voltage, Vdc is the DC voltage, D is the duty cycle, and α is the boost coefficient.

[0077] The Flyback algorithm is an algorithm used for voltage step-up and step-down. Its basic principle is to adjust the output voltage by controlling the switching time of the voltage converter. The specific implementation steps are: determining the frequency and duty cycle of Flyback, generating a Flyback signal, inputting the Flyback signal to the control end of the voltage converter, and the voltage converter controls the output voltage according to the duty cycle of the Flyback signal; for example, assuming that the frequency of Flyback is 100kHz and the duty cycle is 60%. Then the period of the Flyback signal is 10μs, the high level time is 6μs, and the low level time is 4μs. The voltage converter controls the output voltage according to the duty cycle of the Flyback signal. The average value of the output voltage is 1.6 times the input voltage. This calculation has a large error in reality, so it needs to be improved. The nanosecond pulse high voltage circuit uses an improved Flyback algorithm to convert the DC voltage into a nanosecond pulse high voltage voltage. The calculation formula for the nanosecond pulse high voltage voltage is: Vp=(Vdc*N) / (1-D)*(1+β*Vdc); Where: Vp is the nanosecond pulse high voltage, Vdc is the DC voltage, N is the turns ratio of the transformer, D is the duty cycle, and β is the pulse coefficient.

[0078] Cs is a high-voltage pulse energy storage capacitor, which is converted to the primary of the pulse transformer and connected in series with the DC energy storage capacitor Ce. When the pulse generator is working, it will cause voltage fluctuations on the DC energy storage capacitor Ce. In order to output a stable nanosecond pulse peak voltage, the capacity of the DC energy storage capacitor Ce should satisfy the following formula: ; Ce is the DC energy storage capacitor, Ns is the transformation ratio of the pulse boost transformer, Cs is the high-voltage pulse energy storage capacitor, Nc is the transformation ratio of the pulse isolation transformer, and Cz is the load capacitor.

[0079] In order to reduce the switching loss of the semiconductor switch of the pulse generator and achieve zero current shutdown, the driving pulse width Pwp of the pulse generator should satisfy the following formula: ; Pwp is the driving pulse width of the pulse generator, Ns is the transformation ratio of the pulse boost transformer, and Cs is the high-voltage pulse energy storage capacitor.

[0080] Pulse DC power supply rated power P DC21， The following formula should be satisfied: ; The pulse DC power supply is mainly used to provide DC power for the pulse generator, and to control the frequency of the high-frequency H-bridge inverter in the pulse DC power supply through two PWM drives, change the DC voltage value of the pulse DC power supply, and adjust the peak voltage of the nanosecond pulse high voltage. DC21 is the rated power of the pulse DC power supply, Cs is the DC energy storage capacitor, U pmax is the highest pulse peak voltage of the pulse generator, f max is the maximum operating frequency of the pulse generator.

[0081] In order to improve the reliability of the pulse generator and prevent the voltage breakdown of the semiconductor switch of the pulse generator, an RCD protection circuit should be set. At the same time, the maximum output voltage U DC21， The following formula should be satisfied: ; U DC21 Us is the maximum output voltage of the pulse DC power supply, and Us is the rated operating voltage of the semiconductor switch of the pulse generator.

[0082] In order to achieve precise control of the peak pulse voltage on the load, the control accuracy of the output voltage of the pulse DC power supply should be improved, the operating frequency of the high-frequency H-bridge inverter of the pulse DC power supply in the nanosecond pulse high-voltage circuit should be improved, and the resonant capacitor value of the pulse DC power supply should be selected reasonably. At the same time, in order to reduce the switching loss of the semiconductor switch of the high-frequency H-bridge inverter in the pulse DC power supply and achieve zero current shutdown, the capacitance of the resonant capacitor Cb and the resonant inductor Lb should be selected, and the PWM drive pulse width control requirements should be met. The capacitance of the resonant capacitor Cb and the resonant inductor Lb should satisfy the following formula: ; ; Cb is the resonant capacitor, Lb is the resonant inductor or the leakage inductance of the high-frequency step-up transformer in the pulse DC power supply, Nb is the transformation ratio of the high-frequency step-up transformer in the pulse DC power supply, C22 is the filter capacitor in the pulse DC power supply, and Pwb is the PWM drive pulse width of the high-frequency H-bridge inverter in the pulse DC power supply.

[0083] The output of the superposition of the DC high voltage and the nanosecond pulse high voltage, the superposition voltage is calculated as follows: Vtotal=Vhv+Vp*(1+ε*Vhv) Where: Vtotal is the superposition voltage, Vhv is the high voltage DC voltage, Vp is the nanosecond pulse high voltage voltage, and ε is the superposition coefficient.

[0084] A specific embodiment, a schematic diagram of a DC high voltage superimposed nanosecond pulse power supply and a control method is shown in Figure 1 .

[0085] The input power of the AC-DC conversion circuit is three-phase industrial frequency AC power. The three-phase industrial frequency AC power of A, B, and C is connected to the three-phase rectifier composed of V1~V6 semiconductor switches through inductors L1, L2, and L3 respectively for rectification. The filter capacitor C1 filters and converts it into a DC power supply DC1. The DC power supply DC1 supplies power to the high-voltage DC circuit and the nanosecond pulse high-voltage circuit at the same time. The semiconductor switches V1~V6 are IGBTs or MOSFETs. 11, 12, 13, 14, 15, and 16 of the semiconductor switches V1~V6 are connected to the PWM drive control to adjust the AC-DC conversion circuit, improve the power factor of the power supply, and avoid the interference of high-order harmonics on the power grid.

[0086] The high-voltage DC circuit includes a high-frequency H-bridge inverter composed of V11~V14 fully controlled semiconductor switches, a resonant capacitor C11, a high-frequency step-up transformer TR1, and a high-frequency high-voltage rectifier circuit composed of D11~D14 diodes. The high-voltage DC circuit controls the frequency of the high-frequency H-bridge inverter through two PWM1 and PWM2 drives to control the size of the high-voltage DC circuit. One end of the DC11 high-voltage DC output is grounded, and the other end of the DC11 high-voltage DC output is connected to the reactor Z1 through the current limiting resistor R11. The circuit equivalent model of the reactor Z1 is a capacitor Cz in parallel with a variable resistor Rz and a voltage regulator Dz in series.

[0087] The high-voltage DC circuit outputs a continuous DC high voltage on the reactor, generating a stable electric field, forming a basic DC corona discharge, and driving the charged particles in the gas to move along the direction of the electric field until they are captured by the dust collecting grounding electrode.

[0088] The nanosecond pulse high voltage circuit is mainly composed of a pulse DC power supply, a pulse generator, a high-voltage pulse energy storage capacitor Cs, a magnetic compression circuit MZ21, and a pulse isolation transformer TR23. The pulse DC power supply includes a high-frequency H-bridge inverter composed of V21~V24 semiconductor switches, a resonant capacitor Cb, a resonant inductor Lb, a high-frequency boost transformer TR21, a high-frequency rectifier circuit composed of D21~D24 diodes, a filter capacitor C22, a current limiting inductor L21, and a diode D21. The pulse generator includes a semiconductor switch V25, an RCD protection circuit composed of D25, R11, and C24, a DC energy storage capacitor Ce, and a pulse boost transformer TR22. The peak voltage of the nanosecond pulse high voltage is adjusted by changing the DC voltage value of the pulse DC power supply through two PWM3 and PWM4 drive controls to control the frequency of the high-frequency H-bridge inverter in the pulse DC power supply. The repetition frequency of the nanosecond pulse high voltage is adjusted by a PWM5 drive control to control the frequency of the semiconductor switch in the pulse generator. One end of the high-voltage pulse output of Pulse2 is grounded, and the other end of the high-voltage pulse output of Pulse2 is connected to the reactor Z1 through the high-voltage DC isolation capacitor C26. The circuit equivalent model of the reactor Z1 is a capacitor Cz in parallel with a variable resistor Rz and a voltage regulator tube Dz in series.

[0089] The nanosecond pulse high voltage circuit outputs nanosecond pulse high voltage at a repetition frequency on the reactor. The rising edge of the nanosecond pulse high voltage is less than or equal to 300ns, the pulse width is less than 1us, and the peak voltage can be adjusted. The nanosecond pulse high voltage is superimposed on the DC voltage generated by the high-voltage DC circuit through the high-voltage coupling capacitor. Within 1us, a pulse high-voltage electric field is quickly formed to ionize the gas passing through the reactor with high intensity, forming high-concentration charged ions and free radicals in the gas, which produce electrochemical reactions with odor and odor molecules to eliminate odor and odor in the gas.

[0090] DC high voltage superimposed nanosecond pulse power waveform, see Figure 2 , the high-voltage DC circuit controls the output DC11, and the nanosecond pulse high-voltage circuit controls the output nanosecond pulse voltage Pulse2. After coupling and superposition, the DC plus nanosecond pulse voltage DP1 is output on the load. In the figure, the output DC voltage DC11 is about 30KV, the output nanosecond pulse voltage Pulse2 nanosecond pulse peak voltage is about 60kV, and the DC plus nanosecond pulse voltage DP1 peak voltage is about 90KV.

[0091] Nanosecond pulse high voltage circuit waveform diagram see Figure 3, PWM5 is the driving control of the semiconductor switch V25 in the pulse generator, which controls the working pulse width and frequency of the semiconductor switch V25, Ip is the pulse current flowing through the semiconductor switch V25 in the pulse generator, Pulse1 is the microsecond pulse voltage output after being boosted by the pulse boost transformer TR22 in the pulse generator, and Pulse2 is the nanosecond pulse voltage output after being compressed by the magnetic compression circuit MZ21 and isolated by the pulse isolation transformer TR23.

[0092] Comparison between DC high voltage superimposed with nanosecond pulse high voltage and DC high voltage, see Figure 4 , the peak voltage output of 90KV when the reactor is connected to DC high voltage superimposed on nanosecond pulse high voltage is compared with the reactor connected to DC high voltage 90KV. When the reactor is connected to DC high voltage 90KV, it can provide a large average electric field strength and ionize a very high density of electrons and ions, but due to the high average electric field strength, it brings two major problems. The first problem is the insulation problem. The high average electric field strength causes the gas to be easily broken down and short-circuited after the reactor is introduced into the working gas. It cannot operate normally under normal conditions. Reducing the DC voltage operation value voltage to work will cause the density of generated electrons and ions to decrease, affecting the pollution control efficiency of the reactor. The second problem is the high operating energy consumption, high average electric field strength, and large average current. The product of the two is power, resulting in a large operating energy consumption. Even if the DC voltage is reduced from 90KV to 50KV, the operating energy consumption is still greater than the operating energy consumption of DC 30KV plus 60KV nanosecond pulse voltage, with a peak value of 90KV output. When the peak voltage output of DC high voltage superimposed on nanosecond pulse high voltage is 90KV, the 90KV nanosecond peak voltage output can instantly generate high-density electrons and ions in the reactor. The short output time will not cause the working gas to break down and short-circuit, and the electron and ion density is high, which can greatly improve the efficiency of reactor pollution control and maintain high efficiency at the same time. At the same time, the number of nanosecond peak voltage outputs can be accurately controlled according to the residence time of the polluted gas in the reactor, and the operating energy consumption can be accurately controlled. DC high voltage superimposed on nanosecond pulse high voltage power supply, because DC high voltage is not required to generate high-density electrons and ions, DC high voltage can maintain a very low voltage value, and the DC high voltage output can be appropriately adjusted according to the gas flow rate inside the reactor to generate a stable electric field, driving the charged particles in the gas to move along the direction of the electric field until the dust collecting grounding electrode is captured, and the DC high voltage operation output energy consumption is also very low.

[0093] Compared with the pulse power supply whose pulse width is between tens of microseconds and milliseconds, the pulse plus DC power supply is still very easy to cause high voltage breakdown and short circuit due to the wide pulse voltage width, thus losing the dust removal effect. DC high voltage superimposed on nanosecond pulse high voltage also has great advantages.

[0094] A DC high voltage superimposed nanosecond pulse power supply and control method is applied to existing particle removal / defogging devices and odor removal devices. Figure 5 .

[0095] A DC high voltage superimposed nanosecond pulse power supply and control method is applied to a DC high voltage superimposed nanosecond pulse integrated environmental protection device. Figure 6 .

[0096] A DC high voltage superimposed nanosecond pulse power supply and control method is applied to the electrostatic precipitator of a 1000MW coal-fired power generation unit. The array of 6×530 electric fields is configured. Figure 7 As shown, the electrostatic precipitator of a typical 1000MW coal-fired power generation unit is equipped with an array of 6×530 electric fields, that is, two precipitators are also configured with A1, A2, A3, A4, A5, B1, B2, B3, B4, B5, C1, C2, C3, C4, C5 electric fields. Each electric field is equipped with an 80KV2.0A high-voltage power supply, and the total power of 30 power supplies reaches 4800KW. Keeping the mechanical body of the electrostatic precipitator unchanged and upgrading it to DC high voltage superimposed with nanosecond pulse high voltage can improve the dust removal efficiency of the electrostatic precipitator and reduce operating energy consumption. When building a new project, the first-level electric field can also be reduced, such as removing the A5, B5, and C5 electric fields, reducing the size of the electrostatic precipitator, reducing site requirements, reducing costs, and extremely low operating costs.

[0097] 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 will be implemented. These modifications and implementation methods will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A DC high voltage superimposed nanosecond pulse power supply, consisting of an AC-DC conversion circuit, a high voltage DC circuit, and a nanosecond pulse high voltage circuit, characterized in that: The high-voltage DC circuit can output DC high voltage, and the nanosecond pulse high-voltage circuit can output nanosecond pulse high voltage. The output end of the high-voltage DC circuit is connected via a current-limiting resistor, and the output end of the nanosecond high-voltage pulse is connected to a high-voltage coupling capacitor via a pulse isolation transformer. The two work together to form an output in which DC high voltage and nanosecond pulse high voltage are superimposed on each other on the reactor. The AC-DC conversion circuit uses an improved PWM algorithm to achieve the conversion of AC voltage to DC voltage, and its DC voltage is calculated according to the following formula: Vdc=(1 / 2)*Vm*(1+sin(ωt))*(1+k*sin(2ωt)); Where: Vdc is the DC voltage, Vm is the maximum value of the AC voltage, ω is the angular frequency of the AC voltage, t is the time, and k is the modulation coefficient.

2. According to the DC high voltage superimposed nanosecond pulse power supply of claim 1, it is characterized in that: The capacitance of the high-voltage coupling capacitor is greater than or equal to 5 times the capacitance of the reactor capacitor; the nanosecond pulse high-voltage circuit is composed of a pulse DC power supply, a pulse generator, a high-voltage pulse energy storage capacitor, a magnetic compression circuit, and a pulse isolation transformer. The pulse isolation transformer ratio range is: 1, 2, 3; the high-voltage pulse energy storage capacitor should satisfy the following formula: ； Cs is the high-voltage pulse energy storage capacitor, Nc is the transformation ratio of the pulse isolation transformer, and Cz is the load capacitance; The magnetic compression circuit is composed of a magnetic switch, which converts the microsecond pulses generated by the pulse generator into nanosecond pulses. The magnetic switch parameters satisfy the following formula: ； N is the number of turns of the magnetic switch coil, S is the cross-sectional area of ​​the magnetic switch core, △Bm is the magnetic flux density of the magnetic switch core, Pulse1 is the voltage on the high-voltage pulse energy storage capacitor, and Tc is the duration of voltage Pulse1; The pulse generator is composed of a fully controlled semiconductor switch, an RCD protection circuit, a DC energy storage capacitor, and a pulse boost transformer, and is used to generate microsecond pulses; the capacity of the DC energy storage capacitor satisfies the following formula: ； Ce is the DC energy storage capacitor, Ns is the transformation ratio of the pulse boost transformer, Cs is the high-voltage pulse energy storage capacitor, Nc is the transformation ratio of the pulse isolation transformer, and Cz is the load capacitor.

3. According to the DC high voltage superimposed nanosecond pulse power supply of claim 1, it is characterized in that: The AC-DC conversion circuit converts three-phase industrial frequency AC power into a DC power supply, and the DC power supply simultaneously supplies power to the high-voltage DC circuit and the nanosecond pulse high-voltage circuit.

4. According to claim 1, a DC high voltage superimposed nanosecond pulse power supply is characterized in that: The high-voltage DC circuit is composed of a high-frequency H-bridge inverter, a resonant capacitor, a resonant inductor, a high-frequency step-up transformer, and a high-frequency high-voltage rectifier circuit. The frequency of the high-frequency H-bridge inverter is controlled by two PWM drives to control the output voltage of the high-voltage DC circuit. The output voltage of the high-voltage DC circuit is greater than or equal to 1.2 times the corona inception voltage value of the reactor.

5. A DC high voltage superimposed nanosecond pulse power supply according to claim 1, characterized in that: The peak voltage of the pulse high voltage output by the nanosecond pulse high voltage circuit is controlled by two PWM drives to control the frequency of the high frequency fully controlled H-bridge inverter in the pulse DC power supply, and the DC voltage value of the pulse DC power supply is changed for control and regulation; the repetition frequency of the pulse high voltage output by the nanosecond pulse high voltage circuit is controlled by one PWM drive to control the frequency adjustment of the semiconductor fully controlled switch in the pulse generator, and satisfies the following formula when applied to air pollution purification: ； L is the total length of the reactor in m, V is the gas flow rate in m / s during air pollution purification, and F is the repetition frequency in HZ.

6. A DC high voltage superimposed nanosecond pulse power supply according to claim 1, characterized in that: The high-voltage DC circuit adopts an improved Boost algorithm to boost the DC voltage to a high-voltage DC voltage. The calculation formula of the high-voltage DC voltage is: Vhv=Vdc / (1-D)*(1+α*Vdc); Where: Vhv is the high voltage DC voltage, Vdc is the DC voltage, D is the duty cycle, and α is the boost coefficient.

7. A DC high voltage superimposed nanosecond pulse power supply according to claim 1, characterized in that: The nanosecond pulse high voltage circuit adopts an improved Flyback algorithm to convert the DC voltage into a nanosecond pulse high voltage voltage. The calculation formula of the nanosecond pulse high voltage voltage is: Vp=(Vdc*N) / (1-D)*(1+β*Vdc); Where: Vp is the nanosecond pulse high voltage, Vdc is the DC voltage, N is the turns ratio of the transformer, D is the duty cycle, and β is the pulse coefficient.

8. A DC high voltage superimposed nanosecond pulse power supply according to claim 1, characterized in that: The calculation formula of the current limiting resistor is: Rx=Vhv / Ihv*(1+γ*Vhv); Where: Rx is the current limiting resistor, Vhv is the high voltage DC voltage, Ihv is the high voltage DC current, and γ is the current limiting coefficient.

9. A DC high voltage superimposed nanosecond pulse power supply according to claim 1, characterized in that: The turns ratio calculation formula of the pulse isolation transformer is: N=Vp / Vhv*(1+δ*Vp); Where: N is the turns ratio of the pulse isolation transformer, Vp is the nanosecond pulse high voltage voltage, Vhv is the high voltage DC voltage, and δ is the pulse isolation coefficient.

10. A DC high voltage superimposed nanosecond pulse power supply according to claim 1, characterized in that: The output of the superposition of the DC high voltage and the nanosecond pulse high voltage, the superposition voltage is calculated as follows: Vtotal=Vhv+Vp*(1+ε*Vhv); Where: Vtotal is the superposition voltage, Vhv is the high voltage DC voltage, Vp is the nanosecond pulse high voltage voltage, and ε is the superposition coefficient.

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