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

Abstract

This invention relates to the field of power electronics technology, and discloses a high-voltage series resonant system for dielectric barrier discharge and its control method. The system includes a high-voltage series resonant circuit, a host computer, and hardware circuitry. The host computer is electrically connected to the hardware circuitry, and the hardware circuitry is electrically connected to the high-voltage series resonant circuit. 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 converts AC power into a high-frequency, high-voltage pulse voltage and provides it to the dielectric barrier discharge load, generating a stable dielectric barrier discharge. The host computer is used to set parameters, and the hardware circuitry controls the switching states of the Buck circuit and the LC series resonant circuit according to the parameters set by the host computer. This achieves precise generation and control of the high-voltage pulse voltage during dielectric barrier discharge, and also improves the system's response speed and control accuracy.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a dielectric barrier discharge high-voltage series resonant system and its control method. Background Technology

[0002] Plasma is a gaseous state of matter formed after ionization. It is the fourth state of matter aggregation besides solid, liquid, and gas, possessing a large number of active particles and exhibiting high chemical activity. Dielectric barrier discharge (DPD) is a commonly used form of gas discharge for generating room-temperature plasma. DPD technology has wide applications in ozone generation, air purification, material surface modification, and plasma medicine. To generate stable and effective DPD, a high-frequency, high-voltage pulse voltage needs to be provided to the discharge load, requiring the power supply system to have high-efficiency power conversion capabilities and precise control performance.

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

[0004] Furthermore, due to the strong capacitive and nonlinear characteristics of dielectric barrier discharge loads, traditional power supplies struggle to effectively drive them. Especially at high frequencies, parameter variations during discharge can alter the circuit's operating modes. Failure to adapt to these changes can lead to unstable discharge and even damage to circuit components. Summary of the Invention

[0005] The purpose of this invention is to provide a dielectric barrier discharge high-voltage series resonant system and its control method, which solves the technical problems of low output voltage regulation accuracy, slow response speed and poor stability of traditional power supplies.

[0006] To solve the above-mentioned technical problems, the present invention provides a high-voltage series resonant system and method for dielectric barrier discharge, wherein the high-voltage series resonant system for dielectric barrier discharge includes a high-voltage series resonant circuit, a host computer, and hardware circuitry.

[0007] The host computer is electrically connected to the hardware circuit, and the hardware circuit is electrically connected to the high-voltage series resonant circuit.

[0008] 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 AC power 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.

[0009] Furthermore, the PFC circuit is connected in parallel with both ends of the power supply;

[0010] The Buck circuit includes a first voltage-regulating capacitor, a first switching transistor, a second switching transistor, a filter inductor, and a second voltage-regulating capacitor.

[0011] The first voltage-stabilizing capacitor, the second switching transistor, and the second voltage-stabilizing capacitor are connected in parallel across the two ends of the PFC circuit. The first switching transistor and the filter inductor are connected in series with one end of the PFC circuit. The first switching transistor is located between the connection terminals of the first voltage-stabilizing capacitor and the second switching transistor, and the filter inductor is located between the connection terminals of the second switching transistor and the second voltage-stabilizing capacitor.

[0012] Furthermore, the LC series resonant circuit includes a third switch, a fourth switch, a fifth switch, a sixth switch, a resonant inductor, and a resonant capacitor;

[0013] The third and fourth switches are connected in series to form the first bridge arm, and the fifth and sixth switches are connected in series to form the second bridge arm. The first bridge arm and the second bridge arm are connected in parallel across the two ends of the second voltage regulator capacitor.

[0014] One end of the resonant inductor is connected between the third and fourth switching transistors, forming connection point a; one end of the resonant capacitor is connected between the fifth and sixth switching transistors, forming connection point b.

[0015] Furthermore, the high-voltage pulse transformer includes four magnetizing inductors, four primary-side equivalent parasitic capacitances, a transformer primary winding, a transformer secondary winding, four secondary-side equivalent parasitic capacitances, and primary-secondary equivalent parasitic capacitances.

[0016] The four magnetizing inductors are connected in series, and the four primary-side equivalent parasitic capacitances are connected in series. One end of the four magnetizing inductors, the four primary-side equivalent parasitic capacitances, and the primary winding of the transformer are all connected to the other end of the resonant inductor. The other end of the four magnetizing inductors, the four primary-side equivalent parasitic capacitances, and the primary winding of the transformer are all connected to the other end of the resonant capacitor.

[0017] The four secondary equivalent parasitic capacitances are connected in series, and the four secondary equivalent parasitic capacitances and the secondary winding of the transformer are all connected to the two ends of the dielectric barrier discharge load.

[0018] Furthermore, 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.

[0019] Furthermore, 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 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.

[0020] 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.

[0021] The DSP controller is connected to the sampling circuit, the communication circuit, and the isolation drive circuit. It is used to compare the output voltage acquired by the sampling circuit with the reference output voltage value to obtain an error signal, generate a pulse width modulation signal, and control the first switching transistor in the Buck circuit through the isolation drive circuit.

[0022] The dielectric barrier discharge high-voltage series resonance control method provided by this invention employs the aforementioned dielectric barrier discharge high-voltage series resonance system, comprising:

[0023] 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;

[0024] S2. When the dielectric barrier discharge load uses a discharge branch, the DSP controller drives the LC series resonant circuit and the Buck circuit through the isolation drive circuit.

[0025] S3. The DSP controller acquires the output voltage and output current of the Buck circuit and the resonant capacitor voltage of the LC series resonant circuit through the sampling circuit. It obtains an error signal by comparing the error signal 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.

[0026] S4. Input the pulse width modulation signal into the isolation drive circuit to obtain the drive signal for the first switching transistor in the Buck circuit;

[0027] S5. The DSP controller obtains the pulse width and frequency modulation signal based on the pulse width and frequency value transmitted from the host computer, and inputs the pulse width and frequency modulation signal into the isolation drive circuit to obtain the drive signals of the third, fourth, fifth and sixth switches in the LC series resonant circuit.

[0028] S6. Based on the different circuit modes of the dielectric barrier discharge load, establish equivalent output circuit models under different circuit states. Substitute the output voltage, output current and resonant capacitor voltage signals obtained from the sampling circuit into the different circuit modes and calculate the output voltage and output current values ​​in the complex frequency domain under different circuit modes.

[0029] The circuit modes include a first circuit mode, a second circuit mode, a third circuit mode, and a fourth circuit mode.

[0030] Furthermore, the first circuit mode corresponds to the time period t0~t1, and the cavity current in the complex frequency domain under the first circuit mode can be calculated as follows:

[0031] (1);

[0032] Where s represents the complex frequency variable, I 1_s1 with I 2_s1 For the resonant current and the equivalent current of the transformer primary side in the complex frequency domain, v o1 and v Cr1 These are the initial values ​​of the output voltage and the resonant capacitor voltage, respectively, in the first circuit mode. s C is the parasitic resistance of the circuit. d and C diel C represents the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side under discharge conditions. r For resonant capacitor, L r For resonant inductance, v buck This refers to the output voltage of the Buck circuit.

[0033] The time-domain resonant current i can be obtained by performing an inverse Laplace transform on formula (1). 1_s1 and the equivalent current i of the transformer primary side 2_s1 The inverse Laplace transform formula used is:

[0034] (2);

[0035] According to formulas (1) and (2), the output voltage v o2It can be solved as:

[0036] (3);

[0037] Among them, C eq The dielectric barrier discharge load is equivalent to the total capacitance on the primary side of the transformer.

[0038] Furthermore, the second circuit mode corresponds to the time period t1~t2, and the cavity current in the complex frequency domain under the second circuit mode can be calculated as follows:

[0039] (4);

[0040] Where s represents the complex frequency variable, I 1_s2 with I 2_s2 For the resonant current and the equivalent current of the transformer primary side in the complex frequency domain, v o2 and v Cr2 These are the initial values ​​of the output voltage and the resonant capacitor voltage in the second circuit mode, respectively. s C is the parasitic resistance of the circuit. d and C diel C represents the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side under discharge conditions. r For resonant capacitor, L r For resonant inductance, v buck C is the output voltage of the Buck circuit. gap This is the third equivalent capacitance;

[0041] The time-domain resonant current i can be obtained by performing an inverse Laplace transform on equation (4). 1_s2 and the equivalent current i of the primary side of the transformer 2_s2 The inverse Laplace transform formula used is:

[0042] (5);

[0043] According to formulas (4) and (5), the output voltage v o3 It can be solved as:

[0044] (6);

[0045] Among them, C eq The dielectric barrier discharge load is equivalent to the total capacitance on the primary side of the transformer.

[0046] Furthermore, the third circuit mode corresponds to the time period t2~t3, and the cavity current in the complex frequency domain under the third circuit mode can be calculated as follows:

[0047] (7);

[0048] Where s represents the complex frequency variable, I 1_s3 with I 2_s3 For the resonant current and the equivalent current of the transformer primary side in the complex frequency domain, v o3 i Lr3 and v Cr_3 These represent the initial values ​​of the output voltage, the current output by the resonant inductor, and the voltage of the resonant capacitor, respectively, in the third circuit mode. R s C is the parasitic resistance of the circuit. d and C diel C represents the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side under discharge conditions. r For resonant capacitor, L r For resonant inductance, v buck This refers to the output voltage of the Buck circuit.

[0049] The inverse Laplace transform of equation (7) yields the time-domain resonant current i. 1_s3 and the equivalent current i of the primary side of the transformer 2_s3 The inverse Laplace transform formula used is:

[0050] (8);

[0051] According to formulas (7) and (8), the output voltage v o4 It can be solved as:

[0052] (9);

[0053] Among them, C eq The dielectric barrier discharge load is equivalent to the total capacitance on the primary side of the transformer.

[0054] Compared with the prior art, the present invention has at least the following beneficial effects:

[0055] This invention utilizes a high-voltage series resonant circuit structure, combining PFC circuit, Buck circuit, LC series resonant circuit, and high-voltage pulse transformer to form a complete conversion link from AC power to high-frequency high-voltage pulse voltage. This efficiently and stably provides the required voltage and current for dielectric barrier discharge loads, ensuring the stability and consistency of the discharge process. Furthermore, combined with hardware circuit control, it achieves precise generation and control of high-frequency high-voltage pulse voltage during dielectric barrier discharge, thereby improving the system's response speed and control accuracy.

[0056] Furthermore, this invention accurately calculates the output voltage and output current values ​​under different circuit modes through complex frequency domain analysis and inverse Laplace transform. At the same time, by adopting a control method that combines a host computer with hardware circuits, the output voltage is precisely adjusted through a DSP controller, further improving the stability and reliability of the system. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the structure of a dielectric barrier discharge high-voltage series resonant system in one embodiment of the present invention;

[0058] Figure 2 This is a waveform diagram of the operation of a dielectric barrier discharge high-voltage series resonant system in one embodiment of the present invention;

[0059] Figure 3 This is an equivalent circuit under different discharge states in one embodiment of the present invention;

[0060] Figure 4 This is the complex frequency domain equivalent circuit of the first circuit mode under the discharge state in one embodiment of the present invention;

[0061] Figure 5 This is the complex frequency domain equivalent circuit of the second circuit mode under the discharge state in one embodiment of the present invention;

[0062] Figure 6 This is the complex frequency domain equivalent circuit of the third circuit mode under the discharge state in one embodiment of the present invention.

[0063] Figure label: v ac 1. Mains voltage; D1, first switch; D2, second switch; Q1, third switch; Q2, fourth switch; Q3, fifth switch; Q4, sixth switch; L f , filter inductor; C f1 First voltage regulator capacitor; C f2 Second voltage regulator 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 capacitances; V T , air gap discharge clamping voltage; C diel1 First equivalent capacitance; C diel2 Second equivalent capacitance; C gap Third equivalent capacitance; V out_ref Output reference voltage; is Transformer primary current; v gs , drive signal; v ab The voltage between points a and b; v Cr , resonant capacitor voltage; v Cgap Third equivalent capacitor voltage; v o Output voltage. Detailed Implementation

[0064] Based on the teachings of this specification, those skilled in the art can form new technical solutions by combining different implementation methods without creating technical contradictions. Such variations should be considered to fall within the protection scope of this patent.

[0065] The following will describe in more detail a dielectric barrier discharge high-voltage series resonant system and its control method according to the present invention, with reference to schematic diagrams, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0066] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0067] Example 1

[0068] like Figure 1 As shown in the figure, this embodiment of the invention proposes a high-voltage series resonant system for dielectric barrier discharge, which includes a high-voltage series resonant circuit, a host computer, and hardware circuitry.

[0069] Specifically, the host computer is electrically connected to the hardware circuit, and the hardware circuit is electrically connected to the high-voltage series resonant circuit. 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 converts AC power into a high-frequency, high-voltage pulse voltage and provides 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 states of the Buck circuit and the LC series resonant circuit according to the parameters set by the host computer.

[0070] The dielectric barrier discharge (DPD) high-voltage series resonant system converts AC power into stable DC power through a PFC circuit. The DC power is then stepped down and initially regulated by a Buck circuit. Next, a high-frequency oscillation signal is generated by an LC series resonant circuit. Finally, the high-voltage pulse transformer boosts the voltage, generating a high-frequency, high-voltage pulse voltage to drive the DPD load to produce a stable discharge. The hardware circuit, as the core unit, acquires the voltage and current signals of the high-voltage series resonant circuit, calculates the control signal using an algorithm, and then controls the switching states of the switches in the Buck circuit and the LC series resonant circuit through an isolation drive circuit, thereby achieving precise regulation of the output voltage and current. The use of the isolation drive circuit effectively isolates the high-voltage and low-voltage components, protecting the hardware circuit from high-voltage interference and improving the system's safety and reliability.

[0071] In this embodiment, the PFC circuit is connected in parallel with the two ends of the power supply, and the Buck circuit includes a first voltage-regulating capacitor C. f1 First switching transistor D1, second switching transistor D2, filter inductor L f Second voltage regulator capacitor C f2 .

[0072] The first voltage regulator capacitor C f1 The second switching transistor D2 and the second voltage-regulating capacitor C f2 The first switching transistor D1 and the filter inductor L are connected in parallel across the two ends of the PFC circuit. f The first switch D1 is connected in series with one end of the PFC circuit, and the first voltage regulator capacitor C is located at the first voltage regulator capacitor C. f1 Between the connection terminal of the second switching transistor D2 and the filter inductor L f Located between the second switching transistor D2 and the second voltage-regulating capacitor C f2 Between the connection ends.

[0073] The Buck circuit allows the system to adjust the output voltage based on the high DC voltage output by the PFC circuit by controlling the on-time of the first switch D1. When the first switch D1 is turned on, current flows through the first switch D1 and the filter inductor L. f The current flows to the load, and simultaneously to the second voltage regulator capacitor C. f2 Charging; when the first switch D1 is turned off, current flows through the second switch D2 and the filter inductor L. f Continue supplying power to the load. The output voltage can be precisely controlled by adjusting the on-time ratio (duty cycle) of the first switching transistor D1. The first voltage regulator capacitor C... f1 and the second voltage regulator capacitor C f2When used in conjunction with [other components], voltage fluctuations can be effectively filtered out, providing a stable DC voltage output.

[0074] In this embodiment, the LC series resonant circuit includes a third switch Q1, a fourth switch Q2, a fifth switch Q3, a sixth switch Q4, and a resonant inductor L. r and resonant capacitor C r .

[0075] The third switch Q1 and the fourth switch Q2 are connected in series to form the first bridge arm, and the fifth switch Q3 and the sixth switch Q4 are connected in series to form the second bridge arm. The first bridge arm and the second bridge arm are connected in parallel to the second voltage regulator capacitor C. f2 The two ends of the resonant inductor L. r One end of the capacitor is connected between the third switch Q1 and the fourth switch Q2, forming connection point a; the resonant capacitor C r One end is connected between the fifth switch Q3 and the sixth switch Q4, forming connection point b.

[0076] The LC series resonant circuit adopts a full-bridge structure. By controlling the switching states of the four switching transistors, an alternating voltage can be generated between connection point a and connection point b, driving the resonant inductor Lr and the resonant capacitor C. r This creates a series resonance. When the driving frequency approaches the resonant frequency, the circuit exhibits maximum voltage gain, effectively improving energy conversion efficiency. Furthermore, by adjusting the driving frequency and the turn-on sequence of the switching transistors, precise control of the output power can be achieved to meet the discharge requirements under different operating conditions.

[0077] In this embodiment, the high-voltage pulse transformer includes four magnetizing inductors L m The four primary-side equivalent parasitic capacitances C p Transformer primary winding, transformer secondary winding, and four secondary equivalent parasitic capacitances C s The equivalent parasitic capacitance C of the primary and secondary sides ps .

[0078] The four excitation inductors L m The four primary-side equivalent parasitic capacitances C are connected in series. p The four magnetizing inductors L are connected in series. m The equivalent parasitic capacitance C of the four primary sides after being connected in series p One end of the primary winding of the transformer is connected to the resonant inductor L. r At the other end, the four magnetizing inductors L connected in series m The equivalent parasitic capacitance C of the four primary sides after being connected in series pThe other end of the primary winding of the transformer is connected to the resonant capacitor C. r The other end.

[0079] The four secondary-side equivalent parasitic capacitances C s The four secondary-side equivalent parasitic capacitances C are connected in series. s Both the secondary winding of the transformer and the secondary winding are connected to the two ends of the dielectric barrier discharge load.

[0080] The high-voltage pulse transformer boosts the high-frequency voltage output by the LC series resonant circuit to the required high voltage level, which is beneficial for the stable discharge of the dielectric barrier discharge load.

[0081] 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 capacitance C connected in series. diel1 and air gap discharge clamping voltage V T The non-discharge branch includes a second equivalent capacitor C connected in series. diel2 and the third equivalent capacitance C gap .

[0082] The dielectric barrier discharge load can reflect electrical characteristics in both discharge and non-discharge states. In the discharge state, the load exhibits the characteristics of a first equivalent capacitance C. diel1 and air gap discharge clamping voltage V T The series connection; in the non-discharge state, the load exhibits the second equivalent capacitance C. diel2 and the third equivalent capacitance C gap The two-branch model accurately describes the nonlinear characteristics of dielectric barrier discharge loads, which is helpful for the design and optimization of system control algorithms. By monitoring the load status, the system can dynamically adjust control parameters to adapt to different discharge conditions, thereby maintaining a stable discharge effect.

[0083] In this embodiment, the hardware circuit includes a communication circuit, a sampling circuit, a DSP controller, and an isolation drive circuit.

[0084] The hardware 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 Buck circuit through the isolation drive circuit. The parameters set by the host computer include reference output voltage value, pulse width value, frequency value, protection voltage value, and protection current value. The sampling circuit is connected to the second voltage regulating capacitor C. f2 One end is connected to a device used to collect the output voltage and current of the Buck circuit and the resonant capacitance C of the LC series resonant circuit. rVoltage. The DSP controller is connected to the sampling circuit, the communication circuit, and the isolation drive circuit. It is used to compare the output voltage acquired 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 switching transistor D1 in the Buck circuit through the isolation drive circuit.

[0085] The hardware circuit exchanges data with the host computer via the communication circuit (which can use a CAN / 485 bus) to receive various parameters set by the operator; it monitors the system's operating status in real time through a sampling circuit; and it implements closed-loop control through a DSP controller to ensure that the system output remains stable at the set value. The use of a DSP controller can effectively reduce steady-state error and improve the system's response speed and stability. Simultaneously, the hardware circuit is also responsible for generating drive signals to control the switching states of each switch in the Buck circuit and the LC series resonant circuit, achieving accurate control of the system.

[0086] Example 2

[0087] like Figures 2-6 As shown, this second embodiment, based on the first embodiment, proposes a high-voltage series resonance control method for dielectric barrier discharge. The control method includes:

[0088] 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.

[0089] S2. When the dielectric barrier discharge load uses a discharge branch, the DSP controller drives the LC series resonant circuit and the Buck circuit through the isolation drive circuit.

[0090] S3. The DSP controller acquires the output voltage and output current of the Buck circuit and the resonant capacitor voltage of the LC series resonant circuit through the sampling circuit. It obtains an error signal by comparing the error signal 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.

[0091] S4. Input the pulse width modulation signal into the isolation drive circuit to obtain the drive signal for the first switch D1 in the Buck circuit.

[0092] S5. The DSP controller obtains the pulse width and frequency modulation signal based on the pulse width and frequency value transmitted from the host computer, and inputs the pulse width and frequency modulation signal into the isolation drive circuit to obtain the drive signals for the third switch Q1, the fourth switch Q2, the fifth switch Q3 and the sixth switch Q4 in the LC series resonant circuit.

[0093] S6. Based on the different circuit modes of the dielectric barrier discharge load, establish equivalent output circuit models under different circuit states. Substitute the output voltage, output current, and resonant capacitor voltage signals obtained from the sampling circuit into the different circuit modes to calculate the output voltage and output current values ​​in the complex frequency domain under different circuit modes. The circuit modes include a first circuit mode, a second circuit mode, a third circuit mode, and a fourth circuit mode.

[0094] The control method described herein achieves precise control of the dielectric barrier discharge process through accurate modeling and real-time calculation of different operating modes of the system. First, various control parameters are set by the host computer to provide the system's operating target. Then, the hardware circuit generates an initial control signal based on these parameters to drive the system startup. 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, the DSP controller calculates a corrected control signal 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 the precise control of the system.

[0095] In this embodiment, the second switch D2 is a SiC diode, and the first switch D1, the third switch Q1, the fourth switch Q2, the fifth switch Q3 and the sixth switch Q4 are all SiC MOSFETs.

[0096] The waveform diagram obtained based on the system of Embodiment 1 and the control method of Embodiment 2 is as follows: Figure 2 As shown, Figure 3 The equivalent circuits of an LC series resonant circuit, a high-voltage pulse transformer, and a dielectric barrier discharge load under different discharge states are shown. 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 These 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 These are the resonant capacitor voltages under the first circuit mode, the second circuit mode, the third circuit mode, and the fourth circuit mode, respectively; v o1v o2 v o3 and v o4 These are the output voltages under the first circuit mode, the second circuit mode, the third circuit mode, and the fourth circuit mode, respectively.

[0097] according to Figure 3 Equivalent circuits under different states yield the complex frequency domain equivalent circuit in the first circuit mode under the discharge state, such as... Figure 4 As shown, the cavity current in the complex frequency domain under the first circuit mode can be calculated as follows:

[0098] (1);

[0099] Where s represents the complex frequency variable, I 1_s1 with I 2_s1 For the resonant current and the equivalent current of the transformer primary side in the complex frequency domain, v o1 and v Cr1 These are the initial values ​​of the output voltage and the resonant capacitor voltage, respectively, in the first circuit mode. s C is the parasitic resistance of the circuit. d and C diel C represents the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side under discharge conditions. r For resonant capacitor, L r For resonant inductance, v buck This refers to the output voltage of the Buck circuit.

[0100] The time-domain resonant current i can be obtained by performing an inverse Laplace transform on formula (1). 1_s1 and the equivalent current i of the primary side of the transformer 2_s1 The inverse Laplace transform formula used is:

[0101] (2);

[0102] According to formulas (1) and (2), the output voltage v o2 It can be solved as:

[0103] (3);

[0104] Among them, C eq The dielectric barrier discharge load is equivalent to the total capacitance on the primary side of the transformer.

[0105] according to Figure 3 Equivalent circuits under different states yield the complex frequency domain equivalent circuit in the second circuit mode under the discharge state, such as... Figure 5 As shown, the cavity current in the complex frequency domain under the second circuit mode can be calculated as follows:

[0106] (4);

[0107] Where s represents the complex frequency variable, I 1_s2 with I 2_s2 For the resonant current and the equivalent current of the transformer primary side in the complex frequency domain, v o2 and v Cr2 These are the initial values ​​of the output voltage and the resonant capacitor voltage in the second circuit mode, respectively. s C is the parasitic resistance of the circuit. d and C diel C represents the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side under discharge conditions. r For resonant capacitor, L r For resonant inductance, v buck C is the output voltage of the Buck circuit. gap This is the third equivalent capacitance;

[0108] The time-domain resonant current i can be obtained by performing an inverse Laplace transform on equation (4). 1_s2 and the equivalent current i of the transformer primary side 2_s2 The inverse Laplace transform formula used is:

[0109] (5)

[0110] According to formulas (4) and (5), the output voltage v o3 It can be solved as:

[0111] (6);

[0112] Among them, C eq The dielectric barrier discharge load is equivalent to the total capacitance on the primary side of the transformer.

[0113] according to Figure 3 Equivalent circuits under different states yield the complex frequency domain equivalent circuit under the third circuit mode in the discharge state, such as... Figure 6 As shown, the cavity current in the complex frequency domain under the third circuit mode can be calculated as follows:

[0114] (7)

[0115] Where s represents the complex frequency variable, I 1_s3 with I 2_s3 For the resonant current and the equivalent current of the transformer primary side in the complex frequency domain, v o3 i Lr3 and v Cr_3 These represent the initial values ​​of the output voltage, the current output by the resonant inductor, and the voltage of the resonant capacitor, respectively, in the third circuit mode. R sC is the parasitic resistance of the circuit. d and C diel C represents the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side under discharge conditions. r For resonant capacitor, L r For resonant inductance, v buck This refers to the output voltage of the Buck circuit.

[0116] The inverse Laplace transform of equation (7) yields the time-domain resonant current i. 1_s3 and the equivalent current i of the transformer primary side 2_s3 The inverse Laplace transform formula used is:

[0117] (8)

[0118] According to formulas (7) and (8), the output voltage v o4 It can be solved as:

[0119] (9);

[0120] Among them, C eq The dielectric barrier discharge load is equivalent to the total capacitance on the primary side of the transformer.

[0121] from Figure 2 As can be seen from the data, during the time period t3~t4, the current returns to zero and all bridge arms are turned off. There is neither energy transfer nor control variable update, so it can be regarded as a "dead zone" and ignored in the calculation.

[0122] In summary, this invention, through a high-voltage series resonant circuit structure, utilizes a combination design of PFC circuit, Buck circuit, LC series resonant circuit, and high-voltage pulse transformer to form a complete conversion link from AC power to high-frequency high-voltage pulse voltage. This can efficiently and stably provide the required voltage and current for dielectric barrier discharge loads, ensuring the stability and consistency of the discharge process. Furthermore, combined with hardware circuit control, it achieves precise generation and control of high-frequency high-voltage pulse voltage during dielectric barrier discharge, thereby improving the system's response speed and control accuracy.

[0123] Furthermore, this invention accurately calculates the output voltage and output current values ​​under different circuit modes through complex frequency domain analysis and inverse Laplace transform. At the same time, by adopting a control method that combines a host computer with hardware circuits, the output voltage is precisely adjusted through a DSP controller, further improving the stability and reliability of the system.

[0124] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A high-voltage series resonant control method for dielectric barrier discharge, 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 uses a discharge branch, the DSP controller drives the LC series resonant circuit and the Buck circuit through the isolation drive circuit. S3. The DSP controller acquires the output voltage and output current of the Buck circuit and the resonant capacitor voltage of the LC series resonant circuit through the sampling circuit. It obtains an error signal by comparing the error signal 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. Input the pulse width modulation signal into the isolation drive circuit to obtain the drive signal for the first switching transistor in the Buck circuit; S5. The DSP controller obtains the pulse width and frequency modulation signal based on the pulse width and frequency value transmitted from the host computer, and inputs the pulse width and frequency modulation signal into the isolation drive circuit to obtain the drive signals of the third, fourth, fifth and sixth switches in the LC series resonant circuit. S6. Based on the different circuit modes of the dielectric barrier discharge load, establish equivalent output circuit models under different circuit states. Substitute the output voltage, output current and resonant capacitor voltage signals obtained from the sampling circuit into the different circuit modes and calculate the output voltage and output current values ​​in the complex frequency domain under different circuit modes. The circuit modes include a first circuit mode, a second circuit mode, a third circuit mode, and a fourth circuit mode; The first circuit mode corresponds to the time period t0~t1. The cavity current in the complex frequency domain under the first circuit mode can be calculated as follows: （1）； Where s represents the complex frequency variable, I 1_s1 with I 2_s1 For the resonant current and the equivalent current of the transformer primary side in the complex frequency domain, v o1 and v Cr1 These are the initial values ​​of the output voltage and the resonant capacitor voltage, respectively, in the first circuit mode. s C is the parasitic resistance of the circuit. d and C diel C represents the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side under discharge conditions. r For resonant capacitor, L r For resonant inductance, v buck This refers to the output voltage of the Buck circuit. The time-domain resonant current i can be obtained by performing an inverse Laplace transform on formula (1). 1_sS1 and the equivalent current i of the primary side of the transformer 2_s1 The inverse Laplace transform formula used is: （2）； According to formulas (1) and (2), the output voltage v o2 It can be solved as: （3）； Among them, C eq The total capacitance of the dielectric barrier discharge load is equivalent to the primary side of the transformer. The second circuit mode corresponds to the time period t1~t2. The cavity current in the complex frequency domain under the second circuit mode can be calculated as follows: （4）； Where s represents the complex frequency variable, I 1_s2 with I 2_s2 For the resonant current and the equivalent current of the transformer primary side in the complex frequency domain, v o2 and v Cr2 These are the initial values ​​of the output voltage and the resonant capacitor voltage in the second circuit mode, respectively. s C is the parasitic resistance of the circuit. d and C diel C represents the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side under discharge conditions. r For resonant capacitor, L r For resonant inductance, v buck C is the output voltage of the Buck circuit. gap This is the third equivalent capacitance; The time-domain resonant current i can be obtained by performing an inverse Laplace transform on equation (4). 1_s2 and the equivalent current i of the transformer primary side 2_s2 The inverse Laplace transform formula used is: （5）； According to formulas (4) and (5), the output voltage v o3 It can be solved as: （6）； Among them, C eq The total capacitance of the dielectric barrier discharge load is equivalent to the primary side of the transformer. The third circuit mode corresponds to the time period t2~t3, and the cavity current in the complex frequency domain under the third circuit mode can be calculated as follows: （7）； Where s represents the complex frequency variable, I 1_s3 with I 2_s3 For the resonant current and the equivalent current of the transformer primary side in the complex frequency domain, v o3 i Lr3 and v Cr_3 These represent the initial values ​​of the output voltage, the current output by the resonant inductor, and the voltage of the resonant capacitor, respectively, in the third circuit mode. R s C is the parasitic resistance of the circuit. d and C diel C represents the parasitic capacitance equivalent to the primary side of the transformer and the capacitance equivalent to the primary side under discharge conditions. r For resonant capacitor, L r For resonant inductance, v buck This refers to the output voltage of the Buck circuit. The inverse Laplace transform of equation (7) yields the time-domain resonant current i. 1_s3 and the equivalent current i of the primary side of the transformer 2_s3 The inverse Laplace transform formula used is: （8）； According to formulas (7) and (8), the output voltage v o4 It can be solved as: （9）； Among them, C eq The dielectric barrier discharge load is equivalent to the total capacitance on the primary side of the transformer.

2. A dielectric barrier discharge high-voltage series resonant system, employing the dielectric barrier discharge high-voltage series resonant control method as described in claim 1, characterized in that, The dielectric barrier discharge high-voltage series resonant system includes a high-voltage series resonant circuit, a host computer, and hardware circuitry. The host computer is electrically connected to the hardware circuit, and the hardware circuit is electrically connected to the high-voltage series resonant circuit. 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 AC power 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.

3. The dielectric barrier discharge high-voltage series resonant system as described in claim 2, characterized in that, The PFC circuit is connected in parallel with both ends of the power supply; The Buck circuit includes a first voltage-regulating capacitor, a first switching transistor, a second switching transistor, a filter inductor, and a second voltage-regulating capacitor. The first voltage-stabilizing capacitor, the second switching transistor, and the second voltage-stabilizing capacitor are connected in parallel across the two ends of the PFC circuit. The first switching transistor and the filter inductor are connected in series with one end of the PFC circuit. The first switching transistor is located between the connection terminals of the first voltage-stabilizing capacitor and the second switching transistor, and the filter inductor is located between the connection terminals of the second switching transistor and the second voltage-stabilizing capacitor.

4. The dielectric barrier discharge high-voltage series resonant system as described in claim 3, characterized in that, The LC series resonant circuit includes a third switch, a fourth switch, a fifth switch, a sixth switch, a resonant inductor, and a resonant capacitor. The third and fourth switches are connected in series to form the first bridge arm, and the fifth and sixth switches are connected in series to form the second bridge arm. The first bridge arm and the second bridge arm are connected in parallel across the two ends of the second voltage regulator capacitor. One end of the resonant inductor is connected between the third and fourth switching transistors, forming connection point a; one end of the resonant capacitor is connected between the fifth and sixth switching transistors, forming connection point b.

5. The dielectric barrier discharge high-voltage series resonant system as described in claim 4, characterized in that, The high-voltage pulse transformer includes four magnetizing inductors, four primary-side equivalent parasitic capacitances, a transformer primary winding, a transformer secondary winding, four secondary-side equivalent parasitic capacitances, and primary-secondary equivalent parasitic capacitances. The four magnetizing inductors are connected in series, and the four primary-side equivalent parasitic capacitances are connected in series. One end of the four magnetizing inductors, the four primary-side equivalent parasitic capacitances, and the primary winding of the transformer are all connected to the other end of the resonant inductor. The other end of the four magnetizing inductors, the four primary-side equivalent parasitic capacitances, and the primary winding of the transformer are all connected to the other end of the resonant capacitor. The four secondary equivalent parasitic capacitances are connected in series, and the four secondary equivalent parasitic capacitances and the secondary winding of the transformer are all connected to the two ends of the dielectric barrier discharge load.

6. The dielectric barrier discharge high-voltage series resonant system as described in claim 5, 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. The non-discharge branch includes a second equivalent capacitor and a third equivalent capacitor connected in series.

7. The dielectric barrier discharge high-voltage series resonant system as described in claim 2, 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. It is used to compare the output voltage acquired by the sampling circuit with the reference output voltage value to obtain an error signal, generate a pulse width modulation signal, and control the first switching transistor in the Buck circuit through the isolation drive circuit.

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