Dielectric barrier discharge high-voltage series resonance system and control method thereof

Abstract

The invention relates to the technical field of power electronics, and discloses a dielectric barrier discharge high-voltage series resonance system and a control method thereof. The system comprises a high-voltage series resonance circuit, an upper computer and a hardware circuit. The upper computer is electrically connected with the hardware circuit, and the hardware circuit is electrically connected with the high-voltage series resonance circuit; wherein the high-voltage series resonance circuit comprises a PFC circuit, a Buck circuit, an LC series resonance circuit, a high-voltage pulse transformer and a dielectric barrier discharge load which are connected in sequence, the high-voltage series resonance circuit converts alternating current into high-frequency high-voltage pulse voltage and provides the high-frequency high-voltage pulse voltage for the dielectric barrier discharge load, and stable dielectric barrier discharge is generated; the upper computer is used for setting parameters, the hardware circuit controls the on-off state of the Buck circuit and the LC series resonance circuit according to the parameters set by the upper computer, accurate generation and control of high-voltage pulse voltage in the dielectric barrier discharge process are achieved, and the response speed and the control precision of the system are also improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power electronics, in particular to a dielectric barrier discharge high-voltage series resonance system and a control method thereof. BACKGROUND

[0002] Plasma is a gaseous state of matter formed after the material is ionized, which is the fourth state of matter in addition to solid, liquid and gas. It has a large number of active particles and shows high chemical activity. Dielectric barrier discharge is a commonly used form of gas discharge for generating normal temperature plasma. Dielectric barrier discharge technology has wide applications in fields such as ozone generation, air purification, material surface modification and plasma medical treatment. In order to generate stable and effective dielectric barrier discharge, high-frequency high-voltage pulse voltage needs to be provided to the discharge load, which requires the power supply system to have high-efficiency power conversion capability and precise control performance.

[0003] Traditional power supplies often use manual adjustment to adjust the output voltage, and establish the interaction relationship between the discharge power supply parameters and the discharge intensity. This manual adjustment method is not only cumbersome to operate, but also difficult to adapt to complex and variable discharge environments, especially in industrial application scenarios that require precise control of discharge parameters.

[0004] In addition, due to the strong capacitive and nonlinear characteristics of the electrical characteristics of the dielectric barrier discharge load, it is difficult for traditional power supplies to effectively drive such loads. Especially in high-frequency working state, the parameter changes in the discharge process will cause the working mode of the circuit to change, and if this change cannot be adapted, the discharge will be unstable, and even the circuit components will be damaged. SUMMARY

[0005] The purpose of the present application is to provide a dielectric barrier discharge high-voltage series resonance system and a control method thereof, which solves the technical problems of low output voltage regulation precision, slow response speed and poor stability of traditional power supplies.

[0006] To solve the above technical problems, the present application provides a dielectric barrier discharge high-voltage series resonance system and method, which comprises a high-voltage series resonance circuit, an upper computer and a hardware circuit. The upper computer is electrically connected to the hardware circuit, and the hardware circuit is electrically connected to the high-voltage series resonance circuit. Among them, the high-voltage series resonant circuit includes a PFC circuit, a Buck circuit, an LC series resonant circuit, a high-voltage pulse transformer and a dielectric barrier discharge load connected in sequence. The high-voltage series resonant circuit is used to convert alternating current into a high-frequency high-voltage pulse voltage and provide it to the dielectric barrier discharge load to generate a stable dielectric barrier discharge; the host computer is used to set parameters, and the hardware circuit controls the switching state of the Buck circuit and the LC series resonant circuit according to the parameters set by the host computer.

[0007] Furthermore, the PFC circuit is connected in parallel with both ends of the power supply; The Buck circuit includes a first voltage-stabilizing capacitor, a first switching tube, a second switching tube, a filter inductor and a second voltage-stabilizing capacitor; The first voltage-stabilizing capacitor, the second switching tube, and the second voltage-stabilizing capacitor are sequentially connected in parallel at both ends of the PFC circuit. The first switching tube and the filter inductor are sequentially connected in series with one end of the PFC circuit. The first switching tube is located between the connection end of the first voltage-stabilizing capacitor and the second switching tube, and the filter inductor is located between the connection end of the second switching tube and the second voltage-stabilizing capacitor.

[0008] Furthermore, the LC series resonant circuit includes a third switch tube, a fourth switch tube, a fifth switch tube, a sixth switch tube, a resonant inductor and a resonant capacitor; The third switching tube and the fourth switching tube are connected in series to form a first bridge arm, the fifth switching tube and the sixth switching tube are connected in series to form a second bridge arm, and the first bridge arm and the second bridge arm are sequentially connected in parallel to the two ends of the second voltage-stabilizing capacitor; One end of the resonant inductor is connected between the third switching tube and the fourth switching tube to form a connection point a; one end of the resonant capacitor is connected between the fifth switching tube and the sixth switching tube to form a connection point b.

[0009] Furthermore, the high-voltage pulse transformer includes four magnetizing inductors, four primary equivalent parasitic capacitors, a transformer primary winding, a transformer secondary winding, four secondary equivalent parasitic capacitors and a primary and secondary equivalent parasitic capacitor; The four excitation inductors are sequentially connected in series, and the four primary equivalent parasitic capacitors are sequentially connected in series. The four excitation inductors connected in series, the four primary equivalent parasitic capacitors connected in series, and one end of the primary winding of the transformer are all connected to the other end of the resonant inductor. The four excitation inductors connected in series, the four primary equivalent parasitic capacitors connected in series, and the other end of the primary winding of the transformer are all connected to the other end of the resonant capacitor. The four secondary side equivalent parasitic capacitances are connected in series, and the four secondary side equivalent parasitic capacitances and the secondary side winding of the transformer are both connected across the dielectric barrier discharge load.

[0010] Further, the dielectric barrier discharge load comprises a discharge branch and a non-discharge branch, the discharge branch comprises a first equivalent capacitor and an air gap discharge clamping voltage connected in series, and the non-discharge branch comprises a second equivalent capacitor and a third equivalent capacitor connected in series.

[0011] Further, the hardware circuit comprises a communication circuit, a sampling circuit, a DSP controller and an isolation driving circuit, the communication circuit is connected with the upper computer and the isolation driving circuit, and is used for receiving parameters set by the upper computer and driving the LC series resonance circuit through the isolation driving circuit, the parameters set by the upper computer include a reference output voltage value, a pulse width value, a frequency value, a protection voltage value and a protection current value; The sampling circuit is connected with one end of the second voltage stabilizing capacitor, and is used for collecting output voltage, output current of the Buck circuit and resonance capacitor voltage of the LC series resonance circuit; The DSP controller is connected with the sampling circuit, the communication circuit and the isolation driving circuit, and is used for comparing the output voltage collected by the sampling circuit with the reference output voltage value to obtain an error signal, generating a pulse width modulation signal, and controlling the first switch tube in the Buck circuit through the isolation driving circuit.

[0012] The dielectric barrier discharge high-voltage series resonance control method provided by the application adopts the dielectric barrier discharge high-voltage series resonance system, and comprises the following steps: S1, parameters of an upper computer are set, and the set parameters of the upper computer are transmitted to a DSP controller through a communication circuit to obtain a reference output voltage value, a pulse width value, a frequency value, a protection voltage value and a protection current value; S2, in the state that the dielectric barrier discharge load adopts a discharge branch, the DSP controller drives an LC series resonance circuit and a Buck circuit through an isolation driving circuit; S3, the DSP controller collects output voltage, output current of the Buck circuit and resonance capacitor voltage of the LC series resonance circuit through a sampling circuit, compares the output voltage with a reference output voltage value in the hardware circuit through operation to obtain an error signal, and calculates the error signal through the DSP controller to obtain a pulse width modulation signal; S4, the pulse width modulation signal is input into the isolation driving circuit to obtain a driving signal of the first switch tube in the Buck circuit; S5, the DSP controller obtains pulse width and frequency modulation signals according to pulse width values and frequency values transmitted by the host computer, and inputs the pulse width and frequency modulation signals into the isolation drive circuit to obtain drive signals of the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube in the LC series resonant circuit; S6, according to different circuit modes of the dielectric barrier discharge load, equivalent output circuit models in different circuit states are established, and the output voltage, the output current and the resonant capacitor voltage signal obtained by the sampling circuit are respectively substituted into different circuit modes to calculate the output voltage and the output current values in the complex frequency domain under different circuit modes. Among them, the circuit mode includes a first circuit mode, a second circuit mode, a third circuit mode and a fourth circuit mode.

[0013] Further, the first circuit mode corresponds to a t0-t1 time period, and the cavity current in the complex frequency domain under the first circuit mode can be calculated as: (1); Among them, s represents a complex frequency variable, I 1_s1 and I 2_s1 are the resonant current and the primary equivalent current of the transformer in the complex frequency domain, v o1 and v Cr1 are the initial value of the output voltage and the initial value of the resonant capacitor voltage under the first circuit mode, R s is the circuit parasitic resistance, C d and C diel are the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side in the discharge state, C r is the resonant capacitor, L r is the resonant inductance, v buck is the Buck circuit output voltage. The inverse Laplace transform of formula (1) can be used to calculate the resonant current i 1_s1 and the primary equivalent current i 2_s1 of the transformer in the time domain, and the inverse Laplace inverse transform formula used is: (2); According to formula (1) and formula (2), the output voltage v o2 can be solved as: (3); Among them, C eq is the total capacitance of the dielectric barrier discharge load equivalent to the primary side of the transformer.

[0014] Further, the second circuit mode corresponds to a t1-t2 time period, and the cavity current in the complex frequency domain under the second circuit mode can be calculated as: (4); Where s represents a complex frequency variable, I 1_s2 with I 2_s2 is the resonant current and the transformer primary equivalent current in the complex frequency domain, v o2 and v Cr2 are the initial values ​​of the output voltage and the resonant capacitor voltage under the second circuit mode, R s is the circuit parasitic resistance, C d and C diel C is the parasitic capacitance of the transformer equivalent to the primary side and the capacitance equivalent to the primary side in the discharge state. r is the resonant capacitor, L r is the resonant inductance, v buck is the output voltage of the Buck circuit, C gap is the third equivalent capacitance; Performing an inverse Laplace transform on formula (4) can yield the resonant current i in the time domain: 1_s2 and the transformer primary equivalent current i 2_s2 , the inverse Laplace transform formula used is: (5); According to formula (4) and formula (5), the output voltage v o3 can be solved as: (6); Among them, C eq The total capacitance of the transformer primary side that is equivalent to the dielectric barrier discharge load.

[0015] Furthermore, the third circuit mode corresponds to the time period t2 to t3, and the intracavity current in the complex frequency domain under the third circuit mode can be calculated as: (7); Where s represents a complex frequency variable, I 1_s3 with I 2_s3 is the resonant current and the transformer primary equivalent current in the complex frequency domain, v o3 、i Lr3 and v Cr_3 are the initial value of the output voltage, the initial value of the current output by the resonant inductor, and the initial value of the voltage of the resonant capacitor under the third circuit mode, respectively. s is the circuit parasitic resistance, C d and C diel C is the parasitic capacitance of the transformer equivalent to the primary side and the capacitance equivalent to the primary side in the discharge state. r is the resonant capacitor, L r is the resonant inductance, v buck The output voltage of the Buck circuit; Performing an inverse Laplace transform on formula (7) can yield the resonant current i in the time domain: 1_s3 and the transformer primary equivalent current i 2_s3 , the inverse Laplace transform formula used is: (8); According to formula (7) and formula (8), the output voltage v o4 can be solved as: (9); Among them, C eq The total capacitance of the transformer primary side that is equivalent to the dielectric barrier discharge load.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention adopts a high-voltage series resonant circuit structure and utilizes a combined design of a PFC circuit, a Buck circuit, an LC series resonant circuit and a high-voltage pulse transformer to form a complete conversion link from alternating current to high-frequency, high-voltage pulse voltage. This can efficiently and stably provide the required voltage and current for the dielectric barrier discharge load, ensuring the stability and consistency of the discharge process. Combined with the control of the hardware circuit, the present invention realizes the precise generation and control of the high-frequency, high-voltage pulse voltage during the dielectric barrier discharge process, and also improves the response speed and control accuracy of the system.

[0017] Furthermore, the present invention accurately calculates the output voltage and output current values ​​under different circuit modes through complex frequency domain analysis and inverse Laplace transform methods. At the same time, a control method combining a host computer and hardware circuits is adopted to achieve precise adjustment of the output voltage through a DSP controller, further improving the stability and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of a dielectric barrier discharge high-voltage series resonance system according to an embodiment of the present invention; Figure 2 This is a waveform diagram of the operation of a dielectric barrier discharge high-voltage series resonance system in one embodiment of the present invention; Figure 3 1 is an equivalent circuit in different discharge states according to an embodiment of the present invention; Figure 4 is a complex frequency domain equivalent circuit of the first circuit mode in the discharge state in one embodiment of the present invention; Figure 5 is a complex frequency domain equivalent circuit of the second circuit mode in the discharge state in one embodiment of the present invention; Figure 6 FIG. 4 is a complex frequency domain equivalent circuit of the third circuit mode in the discharge state in one embodiment of the present invention.

[0019] Reference numeral: v ac , grid voltage; D1, first switch tube; D2, second switch tube; Q1, third switch tube; Q2, fourth switch tube; Q3, fifth switch tube; Q4, sixth switch tube; L f , filter inductor; C f1 , the first voltage stabilizing capacitor; C f2 , the second voltage stabilizing capacitor; L r , resonant inductor; i Lr , resonant current; v buck , Buck circuit output voltage; C r , resonant capacitor; L m , magnetizing inductance; C p , primary side equivalent parasitic capacitance; C s , secondary side equivalent parasitic capacitance; C ps , primary and secondary equivalent parasitic capacitance; V T , air gap discharge clamping voltage; C diel1 , the first equivalent capacitance; C diel2 , the second equivalent capacitance; C gap , the third equivalent capacitance; V out_ref , output reference voltage; i s , transformer primary current; v gs , driving signal; v ab , the voltage between points ab; v Cr , resonant capacitor voltage; v Cgap , the third equivalent capacitor voltage; v o , output voltage. DETAILED DESCRIPTION

[0020] Based on the teachings of this specification, those skilled in the art may form new technical solutions by cross-combining different implementation methods without generating technical contradictions. Such variations should be deemed to fall within the scope of protection of this patent.

[0021] The following is a more detailed description of a dielectric barrier discharge high-voltage series resonant system and its control method according to the present invention, with reference to a schematic diagram. Preferred embodiments of the present invention are shown, and it should be understood that those skilled in the art may modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as being generally known to those skilled in the art and not as limiting the present invention.

[0022] The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are greatly simplified and not to exact scale, and are provided solely for the purpose of assisting in the description of the embodiments of the present invention.

[0023] Embodiment one As Figure 1 shown, the embodiment of the present application proposes a dielectric barrier discharge high-voltage series resonance system, which comprises a high-voltage series resonance circuit, an upper computer and a hardware circuit.

[0024] Specifically, the upper computer is electrically connected with the hardware circuit, and the hardware circuit is electrically connected with the high-voltage series resonance circuit. The high-voltage series resonance circuit comprises a PFC circuit, a Buck circuit, an LC series resonance circuit, a high-voltage pulse transformer and a dielectric barrier discharge load connected in sequence, and is used for converting alternating current into high-frequency high-voltage pulse voltage and providing the dielectric barrier discharge load to generate stable dielectric barrier discharge. The upper computer is used for setting parameters, and the hardware circuit controls the switching state of the Buck circuit and the LC series resonance circuit according to the parameters set by the upper computer.

[0025] The dielectric barrier discharge high-voltage series resonance system performs power factor correction on alternating current through the PFC circuit to convert the alternating current into stable direct current. Then, the direct current is stepped down and preliminarily adjusted through the Buck circuit. Then, a high-frequency oscillation signal is generated through the LC series resonance circuit. Finally, the high-frequency oscillation signal is stepped up by the high-voltage pulse transformer to generate a high-frequency high-voltage pulse voltage, which drives the dielectric barrier discharge load to generate stable discharge. The hardware circuit as a core unit collects voltage and current signals of the high-voltage series resonance circuit, calculates a control signal through an algorithm, and then controls the switching state of each switch tube in the Buck circuit and the LC series resonance circuit through the isolation driving circuit, so as to realize accurate adjustment of output voltage and current. The use of the isolation driving circuit can effectively isolate the high-voltage and low-voltage parts, protect the hardware circuit from high-voltage interference, and improve the safety and reliability of the system.

[0026] In the embodiment, the PFC circuit is connected in parallel with both ends of a power supply, and the Buck circuit comprises a first voltage stabilizing capacitor C f1 , a first switch tube D1, a second switch tube D2, a filter inductor L f and a second voltage stabilizing capacitor C f2 .

[0027] The first voltage stabilizing capacitor C f1 , the second switch tube D2 and the second voltage stabilizing capacitor C f2 are connected in parallel in sequence at both ends of the PFC circuit, the first switch tube D1 and the filter inductor L f are connected in series with one end of the PFC circuit in sequence, the first switch tube D1 is located between the connection end of the first voltage stabilizing capacitor C f1 and the second switch tube D2, and the filter inductor Lf Between the second switch tube D2 and the second voltage stabilizing capacitor C f2 between the connection ends.

[0028] The Buck circuit enables the system to adjust the output voltage by controlling the on-time of the first switch tube D1 based on the high DC voltage output by the PFC circuit. When the first switch tube D1 is turned on, the current flows through the first switch tube D1 and the filter inductor L. f flows to the load, while the second stabilizing capacitor C f2 When the first switch tube D1 is turned off, the current flows through the second switch tube D2 and the filter inductor L f Continue to supply power to the load. By adjusting the on-time ratio (duty cycle) of the first switch tube D1, the output voltage can be accurately controlled. The first voltage stabilizing capacitor C f1 and the second stabilizing capacitor C f2 The combined use of the two can effectively filter out voltage fluctuations and provide stable DC voltage output.

[0029] In this embodiment, the LC series resonant circuit includes a third switch tube Q1, a fourth switch tube Q2, a fifth switch tube Q3, a sixth switch tube Q4, a resonant inductor L r and resonant capacitor C r .

[0030] The third switch tube Q1 and the fourth switch tube Q2 are connected in series to form a first bridge arm, the fifth switch tube Q3 and the sixth switch tube Q4 are connected in series to form a second bridge arm, and the first bridge arm and the second bridge arm are sequentially connected in parallel to the second stabilizing capacitor C f2 The resonant inductor L r One end of the resonant capacitor C is connected between the third switch tube Q1 and the fourth switch tube Q2 to form a connection point a; r One end of is connected between the fifth switch tube Q3 and the sixth switch tube Q4 to form a connection point b.

[0031] The LC series resonant circuit adopts a full-bridge structure. By controlling the switching states of the four switching tubes, an alternating voltage can be generated between the connection point a and the connection point b to drive the resonant inductor Lr and the resonant capacitor C r This creates series resonance. When the drive frequency approaches the resonant frequency, the circuit exhibits maximum voltage gain, effectively improving energy conversion efficiency. Furthermore, by adjusting the drive frequency and the on-off timing of the switch, precise control of output power can be achieved to meet discharge requirements under varying operating conditions.

[0032] In this embodiment, the high voltage pulse transformer includes four excitation inductors Lm , four primary equivalent parasitic capacitors C p , transformer primary winding, transformer secondary winding, four secondary equivalent parasitic capacitors C s And the equivalent parasitic capacitance C of the primary and secondary sides ps .

[0033] The four excitation inductors L m The four primary equivalent parasitic capacitors C p The four magnetizing inductors L are connected in series in sequence. m , the four primary equivalent parasitic capacitors C after series connection p and one end of the primary winding of the transformer are connected to the resonant inductor L r The other end of the four excitation inductors L are connected in series m , the four primary equivalent parasitic capacitors C after series connection p The other end of the primary winding of the transformer is connected to the resonant capacitor C r the other end.

[0034] The four secondary equivalent parasitic capacitances C s The four secondary equivalent parasitic capacitors C s The secondary winding of the transformer is connected to both ends of the dielectric barrier discharge load.

[0035] The high-voltage pulse transformer boosts the high-frequency voltage output by the LC series resonant circuit to a required high voltage level, which is beneficial to the stable discharge of the dielectric barrier discharge load.

[0036] In this embodiment, the dielectric barrier discharge load includes a discharge branch and a non-discharge branch, and the discharge branch includes a first equivalent capacitor C connected in series. diel1 and the air gap discharge clamping voltage V T The non-discharging branch includes a second equivalent capacitor C connected in series diel2 and the third equivalent capacitance C gap .

[0037] The dielectric barrier discharge load can reflect the electrical characteristics in both discharge and non-discharge states. In the discharge state, the load is represented by a first equivalent capacitance C diel1 and the air gap discharge clamping voltage V T In the non-discharge state, the load behaves as a second equivalent capacitor C diel2 and the third equivalent capacitance C gapThe double-branch model can accurately describe the nonlinear characteristics of the dielectric barrier discharge load and is helpful for the design and optimization of the system control algorithm. By monitoring the load state, the system can dynamically adjust the control parameters to adapt to different discharge conditions, thereby maintaining stable discharge effect.

[0038] In the embodiment, the hardware circuit includes a communication circuit, a sampling circuit, a DSP controller, and an isolation driving circuit.

[0039] The hardware circuit is connected with the upper computer and the isolation driving circuit, and is used for receiving parameters set by the upper computer and driving the LC series resonance circuit and the Buck circuit through the isolation driving circuit. The parameters set by the upper computer include a reference output voltage value, a pulse width value, a frequency value, a protection voltage value, and a protection current value. The sampling circuit is connected with one end of a second voltage stabilizing capacitor C f2 , and is used for collecting output voltage and output current of the Buck circuit and resonance capacitor C r voltage of the LC series resonance circuit. The DSP controller is connected with the sampling circuit, the communication circuit, and the isolation driving circuit, and is used for comparing the output voltage collected by the sampling circuit with the reference output voltage value to obtain an error signal, generating a pulse width modulation signal, and controlling the first switch tube D1 in the Buck circuit through the isolation driving circuit.

[0040] The hardware circuit exchanges data with the upper computer through the communication circuit (CAN / 485 bus can be used), receives various parameters set by an operator, monitors the running state of the system in real time through the sampling circuit, and realizes closed-loop control through the DSP controller to ensure that the system output is stable at the set value. The use of the DSP controller can effectively reduce the steady-state error and improve the response speed and stability of the system. Meanwhile, the hardware circuit is also responsible for generating a driving signal to control the switching state of each switch tube in the Buck circuit and the LC series resonance circuit, thereby realizing accurate control of the system.

[0041] Embodiment Two As shown in Figure 2-Figure 6 , the embodiment two proposes a dielectric barrier discharge high-voltage series resonance control method on the basis of the embodiment one. The control method includes: S1, setting parameters of the upper computer, and transmitting the set parameters of the upper computer to the DSP controller through the communication circuit to obtain a reference output voltage value, a pulse width value, a frequency value, a protection voltage value, and a protection current value.

[0042] S2, in the state that the dielectric barrier discharge load adopts the discharge branch, the DSP controller drives the LC series resonance circuit and the Buck circuit through the isolation driving circuit.

[0043] S3. The DSP controller collects the output voltage, output current and resonant capacitor voltage of the Buck circuit and the LC series resonant circuit through a sampling circuit, and obtains an error signal by comparing it with the reference output voltage value in the hardware circuit. After the error signal is calculated by the DSP controller, a pulse width modulation signal is obtained.

[0044] S4. Input the pulse width modulation signal into the isolation driving circuit to obtain a driving signal for the first switch D1 in the Buck circuit.

[0045] S5. The DSP controller obtains a pulse width and frequency modulated signal based on the pulse width and frequency values ​​transmitted from the host computer, and inputs the pulse width and frequency modulated signal into the isolation drive circuit to obtain drive signals for the third switch tube Q1, the fourth switch tube Q2, the fifth switch tube Q3, and the sixth switch tube Q4 in the LC series resonant circuit.

[0046] S6. Establish equivalent output circuit models under different circuit states based on different circuit modes of the dielectric barrier discharge load, substitute the output voltage, output current, and resonant capacitor voltage signals obtained by the sampling circuit into the different circuit modes, and calculate the output voltage and output current values ​​in the complex frequency domain under the different circuit modes. The circuit modes include a first circuit mode, a second circuit mode, a third circuit mode, and a fourth circuit mode.

[0047] The control method achieves precise control of the dielectric barrier discharge process through accurate modeling and real-time calculation of the system's different operating modes. First, various control parameters are set through a host computer to provide the system's operating targets. Then, the hardware circuit generates an initial control signal based on these parameters to drive the system to start. Next, the system's operating status is acquired through real-time sampling and compared with the target value to generate an error signal. Based on the error signal, a corrected control signal is calculated by the DSP controller to adjust the output of the Buck circuit. Simultaneously, the operating state of the LC series resonant circuit is controlled according to preset pulse width and frequency values. Finally, based on real-time sampling data and a detailed mathematical model, the output parameters under different circuit modes are calculated, providing theoretical support for precise control of the system.

[0048] In this embodiment, the second switch tube D2 is a SiC diode, and the first switch tube D1 , the third switch tube Q1 , the fourth switch tube Q2 , the fifth switch tube Q3 and the sixth switch tube Q4 are all SiC MOSFETs.

[0049] The waveforms obtained according to the system of the first embodiment and the control method of the second embodiment are as follows: Figure 2 As shown, Figure 3The equivalent circuits of the LC series resonant circuit, high-voltage pulse transformer, and dielectric barrier discharge load under different discharge states are shown in FIG. The first circuit mode corresponds to the time period t0~t1, the second circuit mode corresponds to the time period t1~t2, the third circuit mode corresponds to the time period t2~t3, and the fourth circuit mode corresponds to the time period t3~t4. Figure 2 in,i Lr1 、i Lr2 、i Lr3 and i Lr4 are the resonant currents in the first circuit mode, the second circuit mode, the third circuit mode, and the fourth circuit mode, respectively; v Cr1 、v Cr2 、v Cr3 and v Cr4 are the resonant capacitor voltages in the first circuit mode, the second circuit mode, the third circuit mode, and the fourth circuit mode, respectively; v o1 、v o2 、v o3 and v o4 are the output voltages in the first circuit mode, the second circuit mode, the third circuit mode, and the fourth circuit mode, respectively.

[0050] according to Figure 3 The equivalent circuits in different states are obtained, and the complex frequency domain equivalent circuit in the first circuit mode in the discharge state is obtained, such as Figure 4 As shown, the intracavity current in the complex frequency domain under the first circuit mode can be calculated as: (1); Where s represents a complex frequency variable, I 1_s1 with I 2_s1 is the resonant current and the transformer primary equivalent current in the complex frequency domain, v o1 and v Cr1 are the initial values ​​of the output voltage and the resonant capacitor voltage under the first circuit mode, R s is the circuit parasitic resistance, C d and C diel C is the parasitic capacitance of the transformer equivalent to the primary side and the capacitance equivalent to the primary side in the discharge state. r is the resonant capacitor, L r is the resonant inductance, v buck The output voltage of the Buck circuit; Performing an inverse Laplace transform on formula (1) can yield the resonant current i in the time domain: 1_s1 and the transformer primary equivalent current i 2_s1 , the inverse Laplace transform formula used is: (2); According to formula (1) and formula (2), the output voltage v o2 may be solved as: (3); Wherein, C eq is the total capacitance of the dielectric barrier discharge load equivalent to the primary side of the transformer.

[0052] According to Figure 3 the equivalent circuit under different states, the complex frequency domain equivalent circuit under the second circuit mode in the discharge state is obtained, as shown in Figure 5 The cavity current in the complex frequency domain under the second circuit mode can be calculated as: (4); Wherein, s represents a complex frequency variable, I 1_s2 and I 2_s2 are the resonance current and the transformer primary equivalent current in the complex frequency domain, v o2 and v Cr2 are the initial value of the output voltage and the initial value of the resonance capacitance voltage under the second circuit mode, R s is the circuit parasitic resistance, C d and C diel are the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side in the discharge state, C r is the resonance capacitance, L r is the resonance inductance, v buck is the Buck circuit output voltage, and C gap is the third equivalent capacitance. The inverse Laplace transform of formula (4) can be used to obtain the resonance current i 1_s2 and the transformer primary equivalent current i 2_s2 in the time domain, and the inverse Laplace inverse transform formula used is: (5) According to formula (4) and formula (5), the output voltage v o3 may be solved as: (6); Wherein, C eq is the total capacitance of the dielectric barrier discharge load equivalent to the primary side of the transformer.

[0053] According to Figure 3 the equivalent circuit under different states, the complex frequency domain equivalent circuit under the third circuit mode in the discharge state is obtained, as shown in Figure 6 The cavity current in the complex frequency domain under the third circuit mode can be calculated as: (7) Where s represents a complex frequency variable, I 1_s3 with I 2_s3 is the resonant current and the transformer primary equivalent current in the complex frequency domain, v o3 、i Lr3 and v Cr_3 are the initial value of the output voltage, the initial value of the current output by the resonant inductor, and the initial value of the voltage of the resonant capacitor under the third circuit mode, respectively. s is the circuit parasitic resistance, C d and C diel C is the parasitic capacitance of the transformer equivalent to the primary side and the capacitance equivalent to the primary side in the discharge state. r is the resonant capacitor, L r is the resonant inductance, v buck The output voltage of the Buck circuit; Performing an inverse Laplace transform on formula (7) can yield the resonant current i in the time domain: 1_s3 and the transformer primary equivalent current i 2_s3 , the inverse Laplace transform formula used is: (8) According to formula (7) and formula (8), the output voltage v o4 can be solved as: (9); Among them, C eq The total capacitance of the transformer primary side that is equivalent to the dielectric barrier discharge load.

[0054] from Figure 2 It can be seen from the figure that during the time period t3 to t4, the current returns to zero and all bridge arms are turned off. There is neither energy transfer nor control variable update. Therefore, it can be regarded as a "dead zone" and ignored in the calculation.

[0055] To summarize, the present invention forms a complete conversion link from AC to high-frequency, high-voltage pulse voltage through a high-voltage series resonant circuit structure, utilizing a combined design of a PFC circuit, a Buck circuit, an LC series resonant circuit, and a high-voltage pulse transformer. This can efficiently and stably provide the required voltage and current for the dielectric barrier discharge load, ensuring the stability and consistency of the discharge process. Combined with the control of the hardware circuit, it realizes the precise generation and control of the high-frequency, high-voltage pulse voltage during the dielectric barrier discharge process, and also improves the response speed and control accuracy of the system.

[0056] Furthermore, the present invention accurately calculates the output voltage and output current values ​​under different circuit modes through complex frequency domain analysis and inverse Laplace transform methods. At the same time, a control method combining a host computer and hardware circuits is adopted to achieve precise adjustment of the output voltage through a DSP controller, further improving the stability and reliability of the system.

[0057] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A dielectric barrier discharge high voltage series resonance system, characterized in that: Including high-voltage series resonant circuit, host computer and hardware circuit; The host computer is electrically connected to the hardware circuit, and the hardware circuit is electrically connected to the high-voltage series resonant circuit; Among them, the high-voltage series resonant circuit includes a PFC circuit, a Buck circuit, an LC series resonant circuit, a high-voltage pulse transformer and a dielectric barrier discharge load connected in sequence. The high-voltage series resonant circuit is used to convert alternating current into a high-frequency high-voltage pulse voltage and provide it to the dielectric barrier discharge load to generate a stable dielectric barrier discharge; the host computer is used to set parameters, and the hardware circuit controls the switching state of the Buck circuit and the LC series resonant circuit according to the parameters set by the host computer.

2. The dielectric barrier discharge high voltage series resonant system according to claim 1, characterized in that: The PFC circuit is connected in parallel with both ends of the power supply; The Buck circuit includes a first voltage-stabilizing capacitor, a first switching tube, a second switching tube, a filter inductor and a second voltage-stabilizing capacitor; The first voltage-stabilizing capacitor, the second switching tube, and the second voltage-stabilizing capacitor are sequentially connected in parallel at both ends of the PFC circuit. The first switching tube and the filter inductor are sequentially connected in series with one end of the PFC circuit. The first switching tube is located between the connection end of the first voltage-stabilizing capacitor and the second switching tube, and the filter inductor is located between the connection end of the second switching tube and the second voltage-stabilizing capacitor.

3. The dielectric barrier discharge high voltage series resonance system according to claim 2, characterized in that: The LC series resonant circuit includes a third switch tube, a fourth switch tube, a fifth switch tube, a sixth switch tube, a resonant inductor and a resonant capacitor; The third switching tube and the fourth switching tube are connected in series to form a first bridge arm, the fifth switching tube and the sixth switching tube are connected in series to form a second bridge arm, and the first bridge arm and the second bridge arm are sequentially connected in parallel to the two ends of the second voltage-stabilizing capacitor; One end of the resonant inductor is connected between the third switching tube and the fourth switching tube to form a connection point a; one end of the resonant capacitor is connected between the fifth switching tube and the sixth switching tube to form a connection point b.

4. The dielectric barrier discharge high voltage series resonance system according to claim 3, characterized in that: The high-voltage pulse transformer includes four magnetizing inductors, four primary equivalent parasitic capacitors, a transformer primary winding, a transformer secondary winding, four secondary equivalent parasitic capacitors and a primary and secondary equivalent parasitic capacitor; The four excitation inductors are sequentially connected in series, and the four primary equivalent parasitic capacitors are sequentially connected in series. The four excitation inductors connected in series, the four primary equivalent parasitic capacitors connected in series, and one end of the primary winding of the transformer are all connected to the other end of the resonant inductor. The four excitation inductors connected in series, the four primary equivalent parasitic capacitors connected in series, and the other end of the primary winding of the transformer are all connected to the other end of the resonant capacitor. The four secondary-side equivalent parasitic capacitors are sequentially connected in series, and the four secondary-side equivalent parasitic capacitors connected in series and the secondary winding of the transformer are both connected to both ends of the dielectric barrier discharge load.

5. The dielectric barrier discharge high voltage series resonant system according to claim 4, characterized in that: The dielectric barrier discharge load includes a discharge branch and a non-discharge branch. The discharge branch includes a first equivalent capacitor and an air gap discharge clamping voltage connected in series, and the non-discharge branch includes a second equivalent capacitor and a third equivalent capacitor connected in series.

6. The dielectric barrier discharge high voltage series resonant system according to claim 1, characterized in that: The hardware circuit includes a communication circuit, a sampling circuit, a DSP controller and an isolation drive circuit. The communication circuit is connected to the host computer and the isolation drive circuit, and is used to receive parameters set by the host computer and drive the LC series resonant circuit and the Buck circuit through the isolation drive circuit. The parameters set by the host computer include a reference output voltage value, a pulse width value, a frequency value, a protection voltage value and a protection current value; The sampling circuit is connected to one end of the second voltage-stabilizing capacitor and is used to collect the output voltage and output current of the Buck circuit and the resonant capacitor voltage of the LC series resonant circuit; The DSP controller is connected to the sampling circuit, the communication circuit and the isolation drive circuit, and is used to compare the output voltage collected by the sampling circuit with a reference output voltage value to obtain an error signal, generate a pulse width modulation signal, and control the first switch tube in the Buck circuit through the isolation drive circuit.

7. A dielectric barrier discharge high voltage series resonance control method, using the dielectric barrier discharge high voltage series resonance system according to any one of claims 1 to 6, characterized in that: The control method includes: S1. Set the parameters of the host computer and transmit the set parameters of the host computer to the DSP controller through the communication circuit to obtain the reference output voltage value, pulse width value, frequency value, protection voltage value and protection current value; S2. When the dielectric barrier discharge load adopts the discharge branch, the DSP controller drives the LC series resonant circuit and the Buck circuit via the isolation drive circuit; S3, the DSP controller collects the output voltage, output current and resonant capacitor voltage of the Buck circuit and the LC series resonant circuit through a sampling circuit, and obtains an error signal by comparing it with the reference output voltage value in the hardware circuit. After the error signal is calculated by the DSP controller, a pulse width modulation signal is obtained; S4, inputting the pulse width modulation signal into the isolation drive circuit to obtain a drive signal for the first switch tube in the Buck circuit; S5. The DSP controller obtains a pulse width and frequency modulated signal based on the pulse width and frequency values ​​inputted from the host computer, and inputs the pulse width and frequency modulated signal into the isolation drive circuit to obtain drive signals for the third switch tube, the fourth switch tube, the fifth switch tube, and the sixth switch tube in the LC series resonant circuit; S6. Establish equivalent output circuit models under different circuit states based on different circuit modes of the dielectric barrier discharge load, substitute the output voltage, output current, and resonant capacitor voltage signals obtained by the sampling circuit into the different circuit modes, and calculate the output voltage and output current values ​​in the complex frequency domain under the different circuit modes; The circuit modes include a first circuit mode, a second circuit mode, a third circuit mode and a fourth circuit mode.

8. The dielectric barrier discharge high voltage series resonance control method according to claim 7, characterized in that: The first circuit mode corresponds to the time period t0 to t1, and the intracavity current in the complex frequency domain under the first circuit mode can be calculated as: （1）； Where s represents a complex frequency variable, I 1_s1 with I 2_s1 is the resonant current and the transformer primary equivalent current in the complex frequency domain, v o1 and v Cr1 are the initial values ​​of the output voltage and the resonant capacitor voltage under the first circuit mode, R s is the circuit parasitic resistance, C d and C diel C is the parasitic capacitance of the transformer equivalent to the primary side and the capacitance equivalent to the primary side in the discharge state. r is the resonant capacitor, L r is the resonant inductance, v buck The output voltage of the Buck circuit; Performing an inverse Laplace transform on formula (1) can yield the resonant current i in the time domain: 1_sS1 and the transformer primary equivalent current i 2_s1 , the inverse Laplace transform formula used is: （2）； According to formula (1) and formula (2), the output voltage v o2 can be solved as: （3）； Among them, C eq The total capacitance of the transformer primary side that is equivalent to the dielectric barrier discharge load.

9. The dielectric barrier discharge high voltage series resonance control method according to claim 7, characterized in that: The second circuit mode corresponds to the time period t1 to t2. The intracavity current in the complex frequency domain under the second circuit mode can be calculated as: （4）； Where s represents a complex frequency variable, I 1_s2 with I 2_s2 is the resonant current and the transformer primary equivalent current in the complex frequency domain, v o2 and v Cr2 are the initial values ​​of the output voltage and the resonant capacitor voltage under the second circuit mode, R s is the circuit parasitic resistance, C d and C diel C is the parasitic capacitance of the transformer equivalent to the primary side and the capacitance equivalent to the primary side in the discharge state. r is the resonant capacitor, L r is the resonant inductance, v buck is the output voltage of the Buck circuit, C gap is the third equivalent capacitance; Performing an inverse Laplace transform on formula (4) can yield the resonant current i in the time domain: 1_s2 and the transformer primary equivalent current i 2_s2 , the inverse Laplace transform formula used is: （5）； According to formula (4) and formula (5), the output voltage v o3 can be solved as: （6）； Among them, C eq The total capacitance of the transformer primary side that is equivalent to the dielectric barrier discharge load.

10. The dielectric barrier discharge high voltage series resonance control method according to claim 7, characterized in that: The third circuit mode corresponds to the time period t2 to t3. The intracavity current in the complex frequency domain under the third circuit mode can be calculated as: （7）； Where s represents a complex frequency variable, I 1_s3 with I 2_s3 is the resonant current and the transformer primary equivalent current in the complex frequency domain, v o3 、i Lr3 and v Cr_3 are the initial value of the output voltage, the initial value of the current output by the resonant inductor, and the initial value of the voltage of the resonant capacitor under the third circuit mode, R s is the circuit parasitic resistance, C d and C diel C is the parasitic capacitance of the transformer equivalent to the primary side and the capacitance equivalent to the primary side in the discharge state. r is the resonant capacitor, L r is the resonant inductance, v buck The output voltage of the Buck circuit; Performing an inverse Laplace transform on formula (7) can yield the resonant current i in the time domain: 1_s3 and the transformer primary equivalent current i 2_s3 , the inverse Laplace transform formula used is: （8）； According to formula (7) and formula (8), the output voltage v o4 can be solved as: （9）； Among them, C eq The total capacitance of the transformer primary side that is equivalent to the dielectric barrier discharge load.

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