WO2024239380A1 - Square-wave driven damped sine pulse high-voltage power supply suitable for dbd excimer uv lamp - Google Patents

Abstract

Disclosed in the present invention is a square-wave driven damped sine pulse high-voltage power supply suitable for a DBD excimer UV lamp, comprising: a square-wave driving circuit connected to a square-wave driving power supply and used for converting a power supply input into a square-wave output; and a booster transformer, the high-voltage side of the booster transformer being connected to the DBD excimer UV lamp, and the low-voltage side of the booster transformer being connected to the square-wave driving circuit, wherein the booster transformer and the DBD excimer UV lamp form a load resonance loop; and the frequency of the square-wave output is 1/N times the resonance frequency of the load resonance loop, so that N damped sine oscillation waves using the resonance frequency of the load resonance loop as the period are formed on the positive half cycle and the negative half cycle of a square wave, the high voltage generated in the first cycle of damped sine oscillation in the positive half cycle and the negative half cycle of the square wave is used for breaking down DBD to form discharge, and the remaining damped sine oscillation waves are used for the time interval between pulses. According to the present invention, by means of the high voltage formed by square-wave driven damped sine pulses, the excitation efficiency of a DBD excimer UV light source is improved.

Description

Square wave driven damped sine pulse high voltage power supply for DBD excimer UV lamp Technical Field

The invention relates to the technical field of DBD light source power supply, and in particular to a square wave driven damped sine pulse high voltage power supply suitable for a DBD excimer UV lamp.

Background Art

The commonly used 254nm ultraviolet rays have the characteristics of pure physical and efficient sterilization, no secondary pollution, and high power. When used in large-area environments, direct irradiation is harmful to the human body and eyes. Therefore, it can only be used in an environment without people. Related studies have shown that the 222nm wavelength ultraviolet rays generated by KrCl krypton chlorine excimer discharge are also effective against many pathogens, but will not have adverse effects on the skin and eyes. This technology is expected to be widely used in the field of public disinfection and sterilization.

Dielectric Barrier Discharge (DBD) is a type of gas discharge in which insulating materials are inserted into the discharge space. When a sufficiently high excitation voltage is applied between the discharge electrodes, the gas between the electrodes will be broken down and micro-discharge will occur in the micro-discharge channel. This discharge structure enables DBD to generate discharges within a wide range of excitation voltage frequency and gas pressure. This type of micro-discharge belongs to an alternating discharge in a high-pressure non-thermal equilibrium state. The discharge is driven by a high voltage of several thousand volts, and the discharge frequency can range from several Hz to several GHz. The discharge consists of a large number of filamentary irregular fast pulse discharge channels, which are called micro-discharges. The time of each micro-discharge is very short, with a lifetime of less than 10ns, a channel radius of no more than 0.1mm, and a current density of up to 0.1-1KA/ ^cm2 . When the external electric field voltage on the gas gap exceeds the breakdown voltage of the gas, the gas is broken down, and then a conductive channel is established. The space charge is transported in the discharge gap and accumulated on the dielectric. At this time, the surface charge of the dielectric will establish an electric field, the direction of which is opposite to the external electric field, thereby weakening the acting electric field and interrupting the discharge current. Re-breakdown will only occur at the same position when the voltage rises back to the original breakdown voltage value, generating micro-discharge again.

Each microdischarge includes three development stages: 1) the formation of discharge, i.e. the breakdown of the electric field; 2) the transport process of charge in the gas, i.e. the formation of continuous current pulses; 3) the excitation and ionization of atoms and molecules.

Since the dielectric barrier discharge circuit contains gas and dielectric barrier layer, its discharge phenomenon is different from the general discharge phenomenon. The circuit contains two different states: discharge and non-discharge in a complete cycle. When the DBD circuit is in the non-discharge stage, it can be equivalent to a structure in which the dielectric capacitor Cd and the air gap capacitor Cg are connected in series; when the circuit is in the discharge stage, the dielectric capacitor Cd and the air gap breakdown discharge maintenance voltage can be connected in series.

Experiments show that to fully utilize the performance of the DBD load, it is necessary not only to apply a high-frequency, steep pulse rise rate dv/dt excitation voltage waveform to it, but also to provide the DBD load with a unique particle state recovery time (the current flowing through the DBD load is close to zero during this stage). However, the existing dielectric barrier discharge load power supply based on series-parallel load resonance is difficult to meet these two requirements at the same time.

The traditional driving modes of DBD excimer light sources are sinusoidal high voltage and pulsed high voltage. The sinusoidal wave driving mode cannot simultaneously take into account the short rise time and time interval requirements of the pulsed high voltage proposed by the DBD excimer light source. In addition, the traditional pulsed high voltage generation method has a complex circuit structure and low output power.

Summary of the invention

The technical problem to be solved by the present invention is to provide a square wave driven damped sinusoidal pulse high voltage power supply suitable for DBD excimer UV lamps. A plurality of damped sinusoidal oscillation waves with the resonant frequency of the load resonant circuit as a period are formed in the positive half cycle and the negative half cycle of the square wave. The first damped sinusoidal cycle in the positive half cycle and the negative half cycle of the square wave generates a high voltage for breaking down the DBD to form a discharge, and the remaining damped sinusoidal oscillation waves are used for the time interval between pulses, thereby forming shorter rising and falling edges and a longer pulse time interval, thereby meeting the high-efficiency driving requirements of the DBD excimer UV lamp.

The present invention provides a square wave driven damped sine pulse high voltage power supply suitable for a DBD excimer UV lamp, comprising:

A square wave driving circuit, connected to the square wave driving power supply, for converting the square wave driving power supply into a square wave output;

A step-up transformer, wherein the high voltage side of the step-up transformer is connected to the DBD excimer UV lamp, and the low voltage side of the step-up transformer is connected to the square wave drive circuit; the step-up transformer and the DBD excimer UV lamp form a load resonant circuit;

The frequency of the square wave output is 1/N times the resonant frequency of the load resonant circuit, so that N damped sinusoidal oscillation waves with the resonant frequency of the load resonant circuit as a period are formed in the positive half cycle and the negative half cycle of the square wave, and the high voltage generated by the first cycle of the damped sinusoidal oscillation in the positive half cycle and the negative half cycle of the square wave is used to break down the DBD to form a discharge, and the remaining damped sinusoidal oscillation waves are used for the time interval between pulses, where 2.5≤N≤20, and N may not be an integer; when the number of resonant points of the load resonant circuit is greater than one, the frequency corresponding to the highest resonant point is taken as the resonant frequency.

Further, when the square wave driving circuit is a half-bridge square wave driving circuit, the low voltage side of the step-up transformer is connected to the square wave driving circuit via a DC blocking capacitor;

When the square wave drive circuit is a full-bridge square wave drive circuit, the low voltage side of the step-up transformer may be connected to the square wave drive circuit via a DC blocking capacitor or directly connected to the square wave drive circuit without a DC blocking capacitor;

When the step-up transformer is connected to the square wave driving circuit via a DC blocking capacitor, the load resonant circuit further includes a DC blocking capacitor.

Furthermore, the value of N satisfies that the frequency range of the square wave output is 14KHz-500KHz.

Furthermore, the voltage of the square wave drive power supply is 12VDC-800VDC.

Furthermore, the resonant frequency of the load resonant circuit is obtained by conventional calculation, software simulation or actual measurement.

The present invention has the following advantages:

1. By properly selecting N, when the square wave operating frequency is in the damped sinusoidal oscillation region, the first cycle of the positive and negative half-cycle damped oscillation of the square wave generates high voltage, so that the DBD excimer UV lamp obtains a steeper pulse edge, and there is a time interval between the positive and negative high-voltage pulses to form a damped sinusoidal pulse with lower high voltage. Therefore, the two requirements of steep pulse high-voltage edge (high dv/dt) and time interval between pulses can be met at the same time. Since the dv/dt of the steeper pulse high-voltage edge (N times) is obtained and the time interval between high-voltage pulses is increased, it is beneficial to provide the particle state recovery time unique to the DBD load (the current flowing through the DBD load is close to zero at this stage), so that the plasma has enough time to recombine between two adjacent discharges, ensuring that there is enough plasma to participate in the discharge of the next pulse, so that the excitation efficiency of the DBD excimer UV light source is increased by 30%-50%.

2. Since no independent inductor is used (as current limiting or impedance matching), but only the leakage inductance of the step-up transformer is used to participate in the resonance, the reduction of the inductance of the resonant network can effectively increase the resonant frequency of the lamp load, which is beneficial to improving the dv/dt of the pulse edge, and the circuit efficiency is high. At the same time, the circuit structure is simplified, the number of components is small, and the cost performance is high.

3. By adopting the working mode that the frequency of the square wave output is 1/N times the resonant frequency of the load resonant circuit, the current flowing through the step-up transformer winding is a damped oscillating current with the load resonant circuit frequency as a period, which is smaller than the current of the step-up transformer working in a non-resonant inductive load. The required low-voltage winding inductance is smaller, the corresponding number of turns is less, the temperature rise of the step-up transformer is lower, and the efficiency is improved.

4. The stability of the output high voltage amplitude is improved: Since the operating frequency of the square wave is only 1/N times the resonant frequency of the load resonant circuit, the load resonant circuit can obtain ( The equivalent Q value of the circuit is not high compared with the working point near the resonance point Fr. The load change has little effect on the working state of the circuit. It is possible to obtain a more stable output high voltage without using complex control circuits such as frequency tracking, and thus obtain a stable lamp output power.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

FIG1 is an amplitude-frequency diagram corresponding to a periodic square wave signal in the prior art;

2 is a schematic diagram of the structure of a square wave driven damped sine pulse high voltage power supply suitable for a DBD excimer UV lamp according to an embodiment of the present invention;

FIG3 is a half-bridge circuit structure of a square wave driving circuit in an embodiment of the present invention;

FIG4 is another half-bridge circuit structure of a square wave driving circuit in an embodiment of the present invention;

FIG5 is a full-bridge circuit structure of a square wave driving circuit in an embodiment of the present invention;

FIG6 is another full-bridge circuit structure of a square wave driving circuit in an embodiment of the present invention;

7 is a schematic diagram of the scanning results of the amplitude-frequency characteristics and the working area of the DBD excimer UV light source load circuit part in an embodiment of the present invention;

FIG8 is a diagram showing the relationship between the square wave driven damped sine pulse high voltage frequency and N=3 in an embodiment of the present invention;

9 is a diagram showing the relationship between the square wave driven damped sine pulse high voltage frequency and N=5 in an embodiment of the present invention;

FIG10 is a diagram showing the relationship between the square wave driven damped sine pulse high voltage frequency and N=7 in an embodiment of the present invention;

FIG11 is a diagram showing the relationship between the square wave driven damped sine pulse high voltage frequency and N=9 in an embodiment of the present invention;

FIG12 is a circuit diagram of a power supply according to an embodiment of the present invention applied to a 150W DBD excimer UV lamp;

13 is a schematic diagram of the driving square wave, damped sinusoidal pulse high voltage and micro-discharge current waveforms measured for the DBD excimer UV lamp when N=5 in the embodiment of FIG. 12 .

DETAILED DESCRIPTION

The embodiment of the present application provides a square wave driven damped sinusoidal pulse high voltage power supply suitable for a DBD excimer UV lamp. A plurality of damped sinusoidal oscillation waves with a resonant frequency of a load resonant circuit as a period are formed in the positive half cycle and the negative half cycle of the square wave. The first damped sinusoidal oscillation cycle of the positive half cycle and the negative half cycle of the square wave generates a high voltage, and the remaining damped sinusoidal oscillation waves are used for the time interval between pulses, thereby forming shorter rising and falling edges and a longer pulse time interval, thereby meeting the high-efficiency driving requirements of the DBD excimer UV lamp.

The technical solution in the embodiment of the present application has the following general idea:

There are several ways to drive traditional DBD excimer UV light sources, with pulsed high voltage and sinusoidal high voltage being the most common. Given that the electrical characteristics of DBD are capacitive loads, and high frequency and high voltage are difficult to achieve on capacitive loads, in order to achieve efficient excitation of DBD excimer light sources, it is necessary to use pulsed high voltage (the dV/dt values of the rising and falling edges are as large as possible), and there must be a time interval between pulses. However, for conventional circuits to meet these conditions at the same time, the circuit structure is complex and the cost is high.

The load side composed of the DBD excimer UV light source, the step-up transformer and the connecting wires has a resonant characteristic. By making full use of this resonant characteristic, it is possible to use a simple circuit structure to achieve the maximum possible driving pulse dv/dt of the DBD excimer light source and the requirement of time interval between pulses.

The Fourier series for a square wave (50% duty cycle) can be expanded as:

Among them, Am is the amplitude of the square wave, then the amplitude of the fundamental wave is 4/π×Am, and the corresponding amplitudes of each higher harmonic are

From Fourier spectrum analysis, we can know that the periodic square wave can be composed of fundamental wave, 3rd harmonic, 5th harmonic, 7th harmonic, 9th harmonic and other higher harmonics as period, the amplitude is 1 of the fundamental wave unit, and each higher harmonic (3, 5, 7, 9, etc.) is (1/3, 1/5, 1/7, 1/9, etc.) of the fundamental wave amplitude, that is, the periodic square wave contains odd high-frequency harmonics, and the amplitude is 1/N of the fundamental wave), as shown in Figure 1.

By utilizing the characteristics of each high-frequency harmonic contained in the square wave and combining the resonance characteristics of the load circuit composed of the DBD excimer light source, the step-up transformer and the connecting wires, an appropriate square wave frequency is selected to make the load composed of the DBD excimer light source, the step-up transformer and the connecting wires resonate near a certain harmonic of the square wave (the frequency of the square wave is only 1/N of the resonant frequency of the load network). Since the resonance point of the DBD excimer load network is N times higher than the square wave frequency and the period is only 1/N times of the square wave period, the dv/dt value is increased as the period decreases, and a damped sinusoidal oscillation is presented in the upper and lower half periods of the square wave. The first pulse of the oscillation generates a high voltage, which is used to break down the DBD to form a discharge, and the time interval between the high-voltage pulses formed by the subsequent damped pulses satisfies the needs of efficiently driving the DBD excimer light source.

Example

This embodiment provides a square wave driven damped sine pulse high voltage power supply suitable for DBD excimer UV lamp, as shown in FIG2 , including:

The square wave driving circuit is connected to a square wave driving power supply (power supply voltage range is 12VDC-800VDC) and is used to convert the square wave driving power supply into a square wave output.

A step-up transformer T1, a high-voltage side (3, 5) of the step-up transformer T1 is connected to a DBD excimer UV lamp (Cd represents a dielectric capacitor; Cg represents a gas capacitor; Vth represents a threshold voltage, i.e., a gas discharge breakdown voltage), and a low-voltage side (1, 2) of the step-up transformer T1 is connected to the square wave drive circuit; the step-up transformer T1 and the DBD excimer UV lamp form a load resonant circuit (when the square wave drive circuit is connected to the step-up transformer T1 via a DC isolation capacitor C, the load resonant circuit includes the DC isolation capacitor C, the step-up transformer T1, and the DBD excimer UV lamp; the square wave drive damped sine pulse high-voltage power supply includes the square wave drive circuit, the DC isolation capacitor C, and the step-up transformer T1).

The frequency of the square wave output is 1/N times the resonant frequency of the load resonant circuit (2.5≤N≤20, and may not be an integer; when the number of resonant points of the load resonant circuit is greater than one, the frequency corresponding to the highest resonant point is taken as the resonant frequency), thereby forming N damped sinusoidal oscillation waves with the resonant frequency of the DBD load as a period in the positive half cycle and the negative half cycle of the square wave, and the high voltage generated by the first cycle of the damped sinusoidal oscillation in the positive half cycle and the negative half cycle of the square wave is used to break down the DBD to form a discharge, and the remaining damped sinusoidal oscillation waves are used for the time interval between pulses to form shorter rising and falling edges and longer pulse time intervals, thereby meeting the high-efficiency driving requirements of the DBD excimer UV light source.

Preferably, the square wave driving circuit can be generated by the two half-bridge circuit structures shown in Figures 3 and 4 or by the two full-bridge circuit structures shown in Figures 5 and 6. The half-bridge or full-bridge circuit is used to generate square waves, which can adapt to a wide power range and is particularly suitable for high-power application scenarios.

When the square wave drive circuit is a half-bridge square wave drive circuit, the low voltage side of the step-up transformer T1 is connected to the square wave drive circuit through a DC blocking capacitor; the load resonant circuit (in the box) of Figure 3 includes a DC blocking capacitor C1, and the load resonant circuit (in the box) of Figure 4 includes two DC blocking capacitors C1 and C2.

When the square wave drive circuit is a full-bridge square wave drive circuit, the low voltage side of the step-up transformer T1 can be connected to the square wave drive circuit through a DC blocking capacitor or directly connected to the square wave drive circuit without a DC blocking capacitor; the load resonant circuit (inside the box) of Figure 5 does not include a DC blocking capacitor, and the load resonant circuit (inside the box) of Figure 6 includes a DC blocking capacitor C1.

The low voltage winding of the boost transformer T1 is connected to the DC blocking capacitor (not used in the full bridge circuit of Figure 5), and the high voltage winding of the boost transformer T1 is connected to the DBD excimer UV lamp to form a resonant network. Since no independent inductor (as current limiting or impedance matching) is used but the leakage inductance of the boost transformer is used to work, the circuit structure is simplified.

In a specific embodiment, the principle of selecting the driving square wave frequency is shown in FIG7. Taking the resonant frequency (Fr) = 135.14KHz formed by the load resonant circuit composed of the DC blocking capacitor C, the step-up transformer T1, and the DBD excimer UV lamp as an example in FIG2 (the Fr resonant frequency is obtained by conventional calculation, software simulation or actual measurement), the sweep frequency range is 0-200KHz, and can be divided into 4 areas according to the different working states of the circuit:

Zone 4: Fw (square wave operating frequency) > Fr; This area is a conventional sinusoidal oscillation operating area. The load resonant circuit is inductive. The square wave drive circuit can achieve soft switching. As the selected frequency increases, du/dv gradually increases, but the time interval of the high-voltage pulse is too short. There is not enough time for plasma recombination in the DBD excimer UV lamp, and the radiation efficiency of the light source is low. In addition, the square wave operating frequency is greater than the resonance point of the load resonant circuit. When it is close to the resonance point, the equivalent circuit Q value is higher. The high-voltage output amplitude is greatly affected by peripheral parameters, and the circuit output power is unstable. To improve the stability of the output high voltage and power, it is necessary to rely on the phase-locked loop to track the square wave frequency to the load resonant frequency. The circuit structure is complex and the cost is high.

Zone 3: (Fr/2.5 =54.056KHz) < Fw (square wave operating frequency) < (Fr=135.14KHz); the load resonant circuit in this area is capacitive, the square wave drive circuit cannot achieve soft switching, and the switching device loss is too large to work.

Zone 2: 14KHz < Fw (square wave operating frequency) < (Fr/2.5 = 54.056KHz); this area is the damped sine working area of the present embodiment. By selecting an appropriate N (such as N=3, 5, 7, 9), the square wave operating frequency Fw=Fr/N=45.04KHz, 27.028KHz, 19.306KHz, 15.016KHz (corresponding to N=3, 5, 7, 9) can be obtained, and the high dv/dt of the high voltage pulse and the time interval between the high voltage pulses have been achieved.

Zone 1: Fw (square wave operating frequency) <14KHz; 20Hz-14KHz is the audio frequency range that can be heard by the human ear, so it is not suitable to work in this area to avoid noise. This area is close to another low-end resonance point formed by the load resonant circuit composed of a DC blocking capacitor, a step-up transformer, and a DBD excimer UV lamp. It should also be avoided to be too close to avoid unstable circuit operation.

Therefore, the value of N is adjusted by changing the operating frequency through the parameter setting of the half-bridge drive circuit or the full-bridge drive circuit (such as the peripheral components of the half-bridge control IC circuit model L6599), and when the value of N satisfies the frequency range of the square wave output of 14KHz-500KHz, noise can be avoided and the normal operation requirements of the circuit can be met.

When N is appropriately selected to make the square wave frequency in the damped sine working area, the DBD excimer UV light source obtains a steeper dv/dt (N times) pulse edge, and there is a time interval for forming a damped sine pulse with lower high voltage between the positive and negative high voltage pulses, which is beneficial to provide the particle state recovery time unique to the DBD load (the current flowing through the DBD load is close to zero at this stage). Therefore, the two requirements of high dv/dt of the pulse high voltage edge and time interval between pulses can be met at the same time, so that the excitation efficiency of the DBD excimer UV light source is increased by 30%-50%.

Although the selection of N can be flexibly set within 2.5-20 according to actual needs, the inventors have found that a better time relationship between square wave drive and damped sine pulse high voltage can be obtained when N is an odd number. For example, Figures 8 to 11 respectively show the frequency relationship between the square wave of the square wave drive damped sine pulse high voltage and the load resonant circuit composed of the DC isolation capacitor, the step-up transformer and the DBD excimer UV lamp when N=3, 5, 7, and 9.

As shown in FIG. 12 , it is a circuit schematic diagram of a 150W DBD excimer UV lamp power supply according to a specific embodiment:

M1 module 120-277Vac AC power input, EMI filter circuit

M2 module PFC power factor correction

M3 module square wave oscillation and power output

M4 module: load resonant circuit consisting of DC blocking capacitor, step-up transformer, and DBD excimer UV lamp

M5 module PFC power factor control circuit

M6 module internal auxiliary power supply

The specific implementation steps for circuit element parameter determination and circuit control can be as follows, where the circuit element numbers refer to Figure 13:

1. Offline measurement of the series value of the dielectric capacitance Cd and the air gap equivalent capacitance Cg of the DBD excimer UV lamp when it is not discharged, as well as the discharge maintenance voltage Vth of the dielectric barrier discharge lamp;

2. Multiply the square wave voltage amplitude by 4/π to get the fundamental wave amplitude, and then multiply the fundamental wave amplitude by (1/N) to get the amplitude of the Nth harmonic. The quality factor of the resonant circuit is Q=5. Consider the discharge maintenance voltage Vth of the dielectric barrier discharge lamp (usually 2000V) to determine the turns ratio of the transformer low-voltage winding and high-voltage winding.

3. According to the turn ratio of the step-up transformer, the inductance value of the winding, the leakage inductance value and other parameters, as well as the Cd and Cg of the DBD excimer UV lamp, the resonant point frequency Fr of the load resonant circuit composed of the DC blocking capacitor, the step-up transformer and the DBD excimer UV lamp is determined by calculation or software simulation, see Figure 7;

4. Based on the obtained resonant point frequency Fr of the load resonant circuit, select the harmonic order N used, and finally determine the operating frequency of the square wave = Fr/N.

According to the above design principles, a set of typical circuit parameters are given below:

DC voltage: 450V; capacitor C1: 0.22uF; turn ratio of step-up transformer T1 = 1:10, low voltage side inductance = 1200uH, leakage inductance = 130uH, high voltage winding inductance = 90mH; DBD excimer UV lamp Cd series Cg = 81pF, the resonance point of the load resonant circuit Fr = 135.14KHz (the lamp is not discharged) After the lamp is discharged, the air gap capacitance is replaced by Vth, the equivalent capacitance increases, and the resonance point of the load resonant circuit drops to 111.11KHz. At this time, the square wave operating frequency is 27.028KHz. (N = 111.11KHz/27.028KHz = 4.11)

Under this set of parameters, the circuit operating waveform is shown in Figure 13, and the specific description is as follows:

Channel CH2 500V/DIV is a square wave with a frequency of 27.028KHz;

Channel CH1 2A/DIV   is the lamp current waveform of DBD excimer UV lamp. Pulse current amplitude = about 6A;

Channel CH4 2KV/DIV is the lamp voltage waveform of DBD excimer UV lamp. Pulse voltage peak value = about 5KV;

X-axis time base 10us/DIV;

The input power of DBD excimer UV lamp = 158W.

The present invention selects N appropriately so that when the square wave operating frequency is in the damped sinusoidal oscillation region, the first cycle of the positive and negative half cycles of the square wave damped sinusoidal oscillation generates high voltage, so that the DBD excimer UV lamp obtains a steeper dv/dt (N times) pulse edge, and there is a damped sinusoidal pulse formation time interval with lower high voltage between the positive and negative high voltage pulses, which is beneficial to provide a particle state recovery time unique to the DBD load (at this stage, the current flowing through the DBD load is close to zero), so that the two requirements of high dv/dt of the pulse high voltage edge and time interval between pulses can be met at the same time, so that the excitation efficiency of the DBD excimer UV light source is improved by 30%-50%. Since no independent inductor (as current limiting or impedance matching) is used, but only the leakage inductance of the step-up transformer is used to participate in the resonance, the reduction of the inductance of the resonant network can effectively increase the resonant frequency of the lamp load, which is beneficial to increase the dv/dt of the pulse edge, and the circuit efficiency is high, while the circuit structure is simplified, the number of components is small, and the cost performance is high. By adopting the working mode that the frequency of the square wave output is 1/N times the resonant frequency of the load resonant circuit, the current flowing through the step-up transformer winding is a damped oscillating current with the load resonant circuit frequency as a period, which is smaller than the current of the step-up transformer working in a non-resonant inductive load, and the winding inductance required for current limiting is smaller, the corresponding number of turns is smaller, the temperature rise of the step-up transformer is lower, and the efficiency is improved. The stability of the lamp output power is improved: Since the square wave frequency is 1/N of the resonant point frequency of the load resonant circuit, the equivalent Q value of the circuit is not high compared with the inductive working area working in zone 4, and the load change has little effect on the working state of the circuit. It is possible to obtain a more stable lamp power without using complex control circuits such as frequency tracking.

Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims (5)

A square wave driven damped sine pulse high voltage power supply suitable for DBD excimer UV lamp, characterized by comprising: A square wave driving circuit, connected to the square wave driving power supply, for converting the square wave driving power supply into a square wave output; A step-up transformer, wherein the high voltage side of the step-up transformer is connected to the DBD excimer UV lamp, and the low voltage side of the step-up transformer is connected to the square wave drive circuit; the step-up transformer and the DBD excimer UV lamp form a load resonant circuit; The frequency of the square wave output is 1/N times the resonant frequency of the load resonant circuit, so that N damped sinusoidal oscillation waves with the resonant frequency of the load resonant circuit as a period are formed in the positive half cycle and the negative half cycle of the square wave, and the high voltage generated by the first cycle of the damped sinusoidal oscillation in the positive half cycle and the negative half cycle of the square wave is used to break down the DBD to form a discharge, and the remaining damped sinusoidal oscillation waves are used for the time interval between pulses, where 2.5≤N≤20, and N may not be an integer; when the number of resonant points of the load resonant circuit is greater than one, the frequency corresponding to the highest resonant point is taken as the resonant frequency. The power supply according to claim 1, characterized in that: When the square wave driving circuit is a half-bridge square wave driving circuit, the low voltage side of the step-up transformer is connected to the square wave driving circuit via a DC blocking capacitor; When the square wave drive circuit is a full-bridge square wave drive circuit, the low voltage side of the step-up transformer may be connected to the square wave drive circuit via a DC blocking capacitor or directly connected to the square wave drive circuit without a DC blocking capacitor; When the step-up transformer is connected to the square wave driving circuit via a DC blocking capacitor, the load resonant circuit further includes a DC blocking capacitor. The power supply according to claim 1 is characterized in that the value of N satisfies the frequency range of the square wave output being 14KHz-500KHz. The power supply according to claim 1 is characterized in that the voltage range of the square wave drive power supply is 12VDC-800VDC. The power supply according to claim 1 is characterized in that the resonant frequency of the load resonant circuit is obtained by conventional calculation, software simulation or actual measurement.