CN219458922U - High power factor bipolar pulse power supply suitable for dielectric barrier discharge - Google Patents

Abstract

The utility model discloses a high-power factor bipolar pulse power supply suitable for dielectric barrier discharge. The power supply consists of a passive power factor correction part and a bipolar high-frequency high-voltage pulse excitation voltage generation part. The power supply can provide bipolar excitation with high rise rate for the load, and can also enable the whole power supply to work under the conditions of high power factor and low harmonic distortion.

Description

High power factor bipolar pulse power supply suitable for dielectric barrier discharge

technical field

The utility model particularly relates to a high power factor bipolar pulse type power supply suitable for dielectric barrier discharge.

Background technique

Dielectric Barrier Discharge (DBD) is a gas discharge phenomenon in which a low-temperature discharge plasma is generated in the air gap by inserting an insulating medium into the air gap between two metal electrodes. When the alternating high-voltage excitation is applied between the high and low voltage electrodes of the DBD load and the breakdown voltage is reached, the gas in the air gap will be broken down and a large number of charged particles will be generated in the air gap. In recent years, dielectric barrier discharge technology has been widely used in industrial fields such as ozone gas generation, plasma display and aerospace.

When the dielectric barrier discharge load structure and the characteristics of the discharge gas are determined, the discharge performance of the dielectric barrier discharge load is completely determined by the excitation of the power supply circuit. A large number of studies have shown that compared with sinusoidal excitation, a high-voltage pulse excitation with a high voltage rise rate and intermittent time can not only improve the discharge uniformity of the load, but also reduce power consumption and generate more active particles, thereby greatly improving the DBD load. work performance. Although pulse circuits represented by cascaded multilevel circuits, power supplies based on magnetic compression principles, and Marx circuits can achieve high rates of rise in load excitation, when applied to higher pulse voltages, the required number of circuit stages As the number of switches increases, the number of switches will increase exponentially, which will complicate the corresponding trigger circuit and isolation technology, and greatly reduce the reliability of the system.

Therefore, it is necessary to design a high power factor bipolar pulsed power supply suitable for dielectric barrier discharge. This power supply can not only provide high rate of rise excitation for the load, but also contains intermittent time in the excitation, which can fully utilize the DBD load. performance. The bipolar high-frequency high-voltage pulse excitation voltage part is a current source structure, which is beneficial to avoid uncontrollable voltage spikes on the DBD load. In addition, the power supply can not only realize power correction in the AC input test, but also the power switch tubes _Q1 and _Q2 share the same ground, the drive signals are the same, and the phase difference is half a cycle, all of which can realize soft switching, so the power supply has circuit loss Low, simple structure, easy to control features.

Utility model content

The technical problem to be solved by the utility model is to provide a high power factor bipolar pulse type power supply suitable for dielectric barrier discharge. Excitation can also make the entire power supply work in a state of high power factor and low harmonic distortion.

The technical solution of the utility model is as follows:

A high power factor bipolar pulsed power supply suitable for dielectric barrier discharge, characterized in that it includes: a power frequency AC power supply, a first diode, a second diode, a third diode, a fourth and second Pole tube, first inductance, second inductance, first power switch tube, second power switch tube and step-up transformer; the first end of the AC power supply is respectively connected to the anode of the first diode and the first The cathodes of the three diodes are connected; the second end of the AC power supply is respectively connected to the anode of the second diode and the cathode of the fourth diode; the cathode of the first diode is respectively connected to the cathode of the fourth diode. The cathode of the second diode, the first end of the first inductance and the first end of the second inductance are connected; the second end of the first inductance is respectively connected to the first power switch tube The second end is connected to the first end of the primary side coil of the step-up transformer; the second end of the second inductance is respectively connected to the second end of the second power switch tube and the primary side of the step-up transformer The second end of the coil is connected; the secondary coil of the step-up transformer is connected to the dielectric barrier discharge load; the anode of the third diode, the anode of the fourth diode, the anode of the first power switch tube The first end is connected to the first end of the second power switch tube.

Optionally, the first inductance and the second inductance are equal in value.

Optionally, the first power switch tube and the second power switch tube are of the same type.

Optionally, the operating frequency of the first power switch tube and the second power switch tube are equal, and the driving signal of the first power switch tube and the driving signal of the second power switch tube have overlapping time.

Optionally, the operating frequencies of the first power switch tube and the second power switch tube are equal, and the duty ratios of the drive signals of the first power switch tube and the drive signal of the second power switch tube are equal and exist Overlap interval; the overlap interval is jointly determined by the parameters of the main circuit of the power supply and the dielectric barrier discharge load, and the duty cycle of the drive signal of the first power switch tube and the drive signal of the second power switch tube is generally not less than 51%, and not higher than 60%.

Optionally, both the first power switch tube and the second power switch tube are NMOS; wherein the first end of the first power switch tube and the first end of the second power switch tube are both NMOS drains , both the second end of the first power switch tube and the second end of the second power switch tube are sources of NMOS.

Beneficial effect:

(1). The bipolar high-frequency high-voltage pulse excitation voltage generation part can provide DBD load with bipolar high-frequency pulse excitation voltage with high rise rate and high fall rate, and the excitation waveform contains intermittent time, which is beneficial to the DBD load. Performance improvements.

(2). The bipolar high-frequency high-voltage pulse excitation voltage generation part is a current source structure, which is beneficial to avoid uncontrollable voltage spikes on the DBD load.

(3). The switching tubes _Q1 and _Q2 can both realize soft switching, and _Q1 and _Q2 share the same ground, so the driving circuit is simple to implement, and the driving signals of _Q1 and _Q2 are the same, with a phase difference of 180°, which is easy to implement.

(4). The organic combination of the power factor correction circuit and the load excitation voltage generation circuit is realized, and the power factor is improved and the circuit harmonic is reduced in the AC input test.

(5). The load voltage rise rate will not be affected by the operating frequency, and the load voltage waveform will not change due to changes in circuit parameters. This circuit has the advantages of good stability and high reliability.

(6). The power supply is only composed of a set of rectifier bridges, two inductors, two switch tubes and a step-up transformer, with a simple structure.

Description of drawings

Fig. 1 is a structural diagram of a power supply disclosed in the utility model.

Figure 2 is an equivalent model diagram of a dielectric barrier discharge load.

Figure 3 is an equivalent circuit diagram of the bipolar high-frequency high-voltage pulse excitation voltage generation part.

Figure 4 is a working waveform diagram of the bipolar high-frequency high-voltage pulse excitation voltage generation part.

Figure 5 is the equivalent circuit diagram of each mode in the first half cycle.

Figure 6 is an equivalent circuit diagram of the passive power factor correction part of the AC input test.

Figure 7 is a working waveform diagram of the passive power factor correction part of the AC input test.

Fig. 8 is a group of load voltage and current waveform diagrams under given parameters.

Among them: Among them, AC is the power frequency AC power supply, the uncontrollable rectifier bridge composed of diodes D ₁ -D ₄ and two inductors L ₁ and L ₂ constitute the passive power factor correction part, and the power switch tubes Q ₁ and Q ₂ are connected with The two inductors _L1 and _L2 and the step-up transformer T constitute the bipolar high-frequency high-voltage pulse excitation voltage generating part. i _DBD is the current flowing through the load, and u _DBD is the voltage on the DBD load.

Detailed ways

In order to facilitate understanding of the utility model, the utility model will be described more comprehensively and in detail below in conjunction with the accompanying drawings and preferred embodiments, but the protection scope of the utility model is not limited to the following specific embodiments.

Unless otherwise defined, all technical terms used hereinafter have the same meanings as commonly understood by those skilled in the art. The terminology used herein is only for the purpose of describing specific embodiments, and is not intended to limit the protection scope of the present utility model.

Example 1:

Fig. 1 is a topological structure diagram of a high power factor bipolar pulsed power supply suitable for dielectric barrier discharge proposed by the utility model, including: a power frequency AC power supply, a first diode, a second diode, and a third diode Tube, fourth diode, first inductance, second inductance, first power switch tube, second power switch tube and step-up transformer. The first end of the AC power supply is respectively connected to the anode of the first diode and the cathode of the third diode; the second end of the AC power supply is respectively connected to the anode of the second diode connected to the cathode of the fourth diode; the cathode of the first diode is respectively connected to the cathode of the second diode, the first end of the first inductance and the first end of the second inductance connected at one end; the second end of the first inductance is respectively connected to the second end of the first power switch tube and the first end of the primary coil of the step-up transformer; the second end of the second inductance The terminals are respectively connected to the second terminal of the second power switch tube and the second terminal of the primary coil of the step-up transformer; the secondary coil of the step-up transformer is connected to a dielectric barrier discharge load; the third two The anode of the pole tube, the anode of the fourth diode, the first end of the first power switch tube and the first end of the second power switch tube are connected.

Figure 3 is an equivalent circuit diagram of the bipolar high-frequency high-voltage pulse excitation voltage generation part. Among them, I _CD1 and I _CD2 are current sources equivalent to the current flowing through large inductors L ₁ and L ₂ respectively, L _S1 and L _S2 are the primary side leakage reactance and secondary side leakage reactance of the transformer respectively, and L _m is The excitation inductance of the transformer, the transformation ratio between the secondary side and the primary side of the transformer is N, C _e and Re _e are the equivalent capacitance and equivalent resistance of the DBD load respectively, i _DBD is the current flowing through the load, and u _DBD is the voltage on the DBD load.

The working process of this part can be divided into two parts: the first half cycle and the second half cycle, which are briefly described as follows: in the first half cycle, the switching tubes _Q1 and _Q2 are turned on at the same time, the transformer is in a short circuit state, and the inductance of the transformer and the load form a resonant circuit. The energy stored in the transformer is released to the DBD load. In this stage, since the leakage reactance of the transformer and the equivalent capacitance value of the DBD load are both small, the DBD load voltage rises sharply. Afterwards, the switching tube _Q1 is turned off, and the DC current source _ICD1 supplies energy to the load through the transformer. The DC current source _ICD2 is still in a short-circuit state. Due to the large excitation inductance of the transformer, the load voltage changes slowly. The working process of the second half cycle is the same as that of the first half cycle, but the polarity of the excitation voltage generated in the load is opposite. Fig. 4 is the working waveform of the bipolar high-frequency high-voltage pulse excitation voltage generation part provided by the utility model.

Specifically, the half working cycle of the bipolar high-frequency high-voltage pulse excitation voltage generation part provided by the utility model can be divided into two modes, namely mode 1 (t ₀ -t ₁ ), mode 2 (t ₁ -t ₂ ). Fig. 5 is an equivalent circuit diagram of two working modes in half a working cycle of the bipolar high-frequency high-voltage pulse excitation voltage generating part provided by the present invention.

Here, the switching period of the power switch tubes _Q1 and _Q2 is set as T, and the duty cycle is D. The values of the two inductors L ₁ and L ₂ are extremely large, and the switching tubes Q ₁ and Q ₂ and the diodes D ₁ -D ₄ are all ideal switching devices.

From Fig. 5, the constraint equations of mode 1 and mode 2 are respectively:

Substituting the initial values in the two modes into the electrical quantity expressions in each mode can be obtained as follows:

When the current on the switch tube _Q2 decreases to 0, the mode 1 ends, thus the expressions of the duration and end time of each mode can be obtained:

In the formula, L _S ＝L _S2 +L _S1 *N ² , U _L , U _C and U _R are the voltages on L _S , _Ce and _Re in the equivalent circuit respectively, and the initial value of load current in mode 1 is i ₀ And U _C initial value U _C (t ₀ )=u ₀ , mode 2 initial value U _C (t ₁ )=u ₁ , i _DBD (t ₁ )=i ₁ =I, i _DBD is the current flowing through the load ,

Voltage peak:

It can be seen from mode 2 that when the resonant current of the DBD load crosses zero, the voltage of the DBD load reaches its peak value U _m , namely:

When the circuit parameters, transformer and load parameters are determined, the resonant frequency of mode 1 and mode 2 is also determined, and will not change due to the change of the switching cycle, and it is also related to the value of the inductance L ₁ and L ₂ It has nothing to do, and at the same time, it also limits the setting of switching frequency and duty cycle. Considering the recovery time T _D required after the DBD load is discharged, the switching frequency range can be determined:

The value range of the driving signal duty cycle of the power switching device:

Fig. 6 is the equivalent circuit diagram of the power factor correction part provided by the utility model, it should be pointed out that the resistance R here is the equivalent resistance of the bipolar high-frequency high-voltage pulse excitation voltage generation part and the DBD load, L=L ₁ || L ₂ , u _in is the AC input voltage, i _in is the input current, and i _L is the current flowing through the inductors L ₁ and L ₂ . Fig. 7 is a working waveform diagram of the power factor correction part provided by the present invention. can be obtained:

The effective value of the current flowing through L:

Power factor measured by AC input:

Power dissipated in equivalent resistance:

The specific implementation steps of circuit component parameter determination and circuit topology control are as follows, where the circuit component labels refer to Figure 1:

1. Measure the equivalent capacitance C _e and equivalent resistance R _e of the dielectric barrier discharge load off-line, and the breakdown voltage V _th of the dielectric barrier discharge load;

2. Determine the parameters and transformation ratio N of the step-up transformer according to the resonant frequency of the load circuit and the highest peak voltage U _m that the dielectric barrier discharge load can withstand.

3. The power consumed when the DBD load is discharged is obtained offline, and the equivalent resistance of the bipolar high-frequency high-voltage pulse excitation voltage generation part is deduced.

4. Determine the values of the first inductance L ₁ and the second inductance L ₂ according to the parameters of the equivalent circuit and the requirements of the passive power factor correction part.

5. Set the duty cycle of the drive pulse according to the resonant frequency determined by the load parameters and transformer parameters, usually set to 53%, the drive pulse of the first power switch tube lags behind or leads the drive pulse of the second power switch tube by half cycle.

6. The frequency range of the drive pulse should be set according to the resonant frequency determined by the load capacitance and transformer inductance. When the frequency and circuit parameters are appropriate, both the first power switch tube _Q1 and the second power switch tube _Q2 can Implement soft switching.

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

AC voltage AC: 0-250V (adjustable);

Inductance L ₁ : 10mH;

Inductance L ₂ : 10mH;

Transformer T: rated frequency 125kHz, primary leakage inductance L _S1 1.4μH, secondary leakage inductance L _S2 4.75mH, excitation inductance L _m 312μH, transformer primary and secondary turns ratio N=9:450;

Driving pulse Pulse1: frequency 125kHz, duty cycle 53%;

Driving pulse Pulse2: frequency 125kHz, duty cycle 53%, lagging Pulse1 half cycle;

The waveform diagram of the load voltage and current under this set of parameters is shown in Figure 8.

Claims (6)

1. A high power factor bipolar pulsed power supply suitable for dielectric barrier discharge, characterized in that it comprises: a power frequency AC power supply, a first diode, a second diode, a third diode, a Four diodes, a first inductor, a second inductor, a first power switch tube, a second power switch tube, and a step-up transformer; the first end of the AC power supply is connected to the anode of the first diode and the step-up transformer respectively. The cathode of the third diode is connected; the second end of the AC power supply is respectively connected with the anode of the second diode and the cathode of the fourth diode; the cathode of the first diode respectively connected to the cathode of the second diode, the first end of the first inductance and the first end of the second inductance; the second end of the first inductance is respectively connected to the first power switch The second end of the tube is connected to the first end of the primary coil of the step-up transformer; the second end of the second inductance is respectively connected to the second end of the second power switch tube and the first end of the step-up transformer The second end of the primary coil is connected; the secondary coil of the step-up transformer is connected to a dielectric barrier discharge load; the anode of the third diode, the anode of the fourth diode, and the first power The first end of the switch tube is connected to the first end of the second power switch tube. 2. The high power factor bipolar pulse power supply suitable for dielectric barrier discharge according to claim 1, characterized in that the first inductance and the second inductance are equal in value. 3. The high power factor bipolar pulse power supply suitable for dielectric barrier discharge according to claim 2, characterized in that the first power switch tube and the second power switch tube are of the same type. 4. The high power factor bipolar pulsed power supply suitable for dielectric barrier discharge according to claim 3, characterized in that the operating frequencies of the first power switch tube and the second power switch tube are equal and the The driving signal of the first power switch transistor and the driving signal of the second power switch transistor have overlapping time. 5. The high power factor bipolar pulse power supply suitable for dielectric barrier discharge according to claim 4, characterized in that, the operating frequencies of the first power switch tube and the second power switch tube are equal and the The duty cycle of the drive signal of the first power switch tube and the drive signal of the second power switch tube are equal and there is an overlapping interval; the overlapping interval is determined by the main circuit parameters of the power supply and the parameters of the dielectric barrier discharge load, and the The duty cycle of the driving signal of the first power switch tube and the driving signal of the second power switch tube is generally not lower than 51% and not higher than 60%. 6. The high power factor bipolar pulsed power supply suitable for dielectric barrier discharge according to claim 4, characterized in that, both the first power switch tube and the second power switch tube are NMOS, wherein the Both the first end of the first power switch tube and the first end of the second power switch tube are NMOS drains, the second end of the first power switch tube and the first end of the second power switch tube Both terminals are NMOS sources.