An energy feedback type bipolar pulse driving circuit suitable for an excimer lamp

Abstract

The application discloses an energy feedback type bipolar pulse driving circuit suitable for excimer lamps. The bipolar pulse driving circuit mainly comprises a symmetric two-way pulse voltage generating part, an excimer lamp energy feedback channel and a three-winding transformer. In the pulse voltage generating part, the charging of a resonance capacitor is automatically completed through a resonance circuit, the energy of the resonance capacitor is released by controlling the turn-on and turn-off of corresponding power switch tubes, a pulse excitation voltage is formed on the excimer lamp, and the energy feedback channel constructed by feedback diodes can realize the automatic feedback of the energy of the excimer lamp to the power supply. The driving circuit disclosed by the application can not only generate a high-frequency bipolar pulse excitation waveform on the excimer lamp, but also is suitable for various different forms of loads, such as ozone generators.

Description

Technical Field

[0001] The present invention relates to the field of power supply for power electronics, and in particular to a power supply suitable for a dielectric barrier discharge excimer lamp. Background Art

[0002] Both theoretical analysis and experimental results indicate that the shape and frequency of the excitation voltage applied to an excimer lamp significantly influence its discharge efficiency. Further experimental results indicate that a bipolar excitation waveform with appropriate rise and fall rates, the necessary idle time for the excitation voltage, and the suppression of multiple oscillations in the excitation voltage waveform can significantly reduce the intensity of the glow discharge, produce a more uniform discharge, and lower the operating temperature of the excimer lamp. To achieve this goal, researchers have proposed various pulsed power supplies with varying structures. While power supplies based on multi-level circuits, Marx circuits, and magnetic compression circuits can generate unipolar or bipolar quasi-square wave excitation pulses in excimer lamps, these power supplies are not practical due to drawbacks such as a large number of components, low operating frequency, and low power supply efficiency. Therefore, in practical applications, bipolar pulse excitation based on the resonance principle is often used to generate excimer lamps. However, although the existing power supply based on the resonance principle has solved the high-frequency operation and pulsed excitation waveform problems of the excimer lamp, it is still unable to adjust the rise and fall rates of the bipolar excitation voltage waveform, the idle time of the excitation voltage, suppress multiple oscillations of the excitation voltage waveform, and realize energy feedback on the excimer lamp according to the characteristics of the excimer lamp.

[0003] Therefore, how to provide a bipolar pulse driving circuit for an excimer lamp that solves the above technical problems is a problem that those skilled in the art need to solve. Summary of the Invention

[0004] This application provides an energy-feedback bipolar pulse drive circuit suitable for excimer lamps. This drive circuit not only has the advantages of a simple circuit structure and easy switch control, but also can adjust circuit parameters according to the specific conditions of the excimer lamp to ensure that the excimer lamp operates in an optimal state.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] An energy-feedback bipolar pulse drive circuit suitable for an excimer lamp, characterized by comprising: a DC power supply, a first resonant inductor (L1), a second resonant inductor (L2), a first diode (D1), a second diode (D2), a third diode (D3), a fourth diode (D4), a fifth diode (D5), a sixth diode (D6), a first resonant capacitor (C1), a second resonant capacitor (C2), a first power switch tube (Q1), a second power switch tube (Q2), and a step-up transformer with a center tap;

[0007] The anode of the DC power supply is respectively connected to the first end of the first resonant inductor (L1), the first end of the second resonant inductor (L2), the cathode of the fifth diode (D5), and the cathode of the sixth diode (D6);

[0008] The second end of the first resonant inductor (L1) is connected to the anode of the first diode (D1);

[0009] The cathode of the first diode (D1) is respectively connected to the anode of the second diode (D2) and the first end of the first resonant capacitor (C1);

[0010] The cathode of the second diode (D2) is connected to the first end of the first power switch tube (Q1);

[0011] The second end of the first resonant capacitor (C1) is connected to the anode of the third diode (D3) and the first end of the first primary winding of the transformer;

[0012] The cathode of the DC power supply is respectively connected to the second end of the first power switch tube (Q1), the second end of the second power switch tube (Q2), the second end of the first primary winding of the transformer, and the first end of the second primary winding of the transformer;

[0013] The second end of the second resonant inductor (L2) is connected to the anode of the fourth diode (D4);

[0014] The cathode of the fourth diode (D4) is respectively connected to the anode of the seventh diode (D7) and the first end of the second resonant capacitor (C2);

[0015] The cathode of the seventh diode (D7) is connected to the first end of the second power switch tube (Q2);

[0016] The second end of the second resonant capacitor (C2) is respectively connected to the anode of the eighth diode (D8) and the second end of the second primary winding of the transformer;

[0017] The first end and the second end of the secondary winding of the transformer are respectively connected to the two ends of the excimer lamp.

[0018] Preferably, the capacitance value of the first resonant capacitor (C1) is equal to the capacitance value of the second resonant capacitor (C2).

[0019] Preferably, the inductance value of the first resonant inductor (L1) is equal to the inductance value of the second resonant inductor (L2).

[0020] Preferably, the operating frequency and duty cycle of the first power switch tube (Q1) and the second power switch tube (Q2) are equal, and the duty cycle is not higher than 0.1.

[0021] Preferably, the operating phases of the first power switch tube (Q1) and the second power switch tube (Q2) differ by 180 degrees.

[0022] Preferably, the first diode (D1), the second diode (D2), the third diode (D3), the fourth diode (D4), the fifth diode (D5), and the sixth diode (D6) are all fast recovery diodes.

[0023] Preferably, the first power switch tube (Q1) and the second power switch tube (Q2) are both NMOS, wherein the first ends of the first power switch tube (Q1) and the second power switch tube (Q2) are both drains of the NMOS; and the second ends of the first power switch tube (Q1) and the second power switch tube (Q2) are both sources of the NMOS.

[0024] Preferably, the first power switch tube (Q1) and the second power switch tube (Q2) can be changed to adjust the output frequency of the power supply.

[0025] Preferably, the secondary side of the transformer can be connected to various types of loads, such as an ozone generator.

[0026] The advantages of the present invention compared with the prior art are:

[0027] (1) A bipolar pulse excitation waveform can be generated on the excimer lamp;

[0028] (2) The driving circuit can make the excimer lamp discharge linearly four times in one cycle, which can fully exert the performance of the excimer lamp load.

[0029] (3) The rise rate of the excitation waveform can be changed by changing the value of the resonant capacitor

[0030] (4) The excitation voltage applied to the excimer lamp will not oscillate multiple times.

[0031] (5) Ability to realize energy feedback from excimer to DC power supply BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the prior art and the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a structural diagram of the driving circuit of the present invention.

[0034] Among them, the power supply provided in this figure is a DC power supply, Q1 is the first power switching device, Q2 is the second power switching device, D1 is the first diode, D2 is the second diode, D3 is the third diode, D4 ​​is the fourth diode, D5 is the fifth diode, D6 is the sixth diode, C1 is the first resonant capacitor, C2 is the second resonant capacitor, T is a high-frequency transformer with a center tap, L1 is the first resonant inductor, and L2 is the second resonant inductor.

[0035] Figure 2 This is the voltage waveform on the gas discharge lamp in steady state.

[0036] Figure 3 This is the waveform of the current flowing through the gas discharge lamp in steady state.

[0037] Figure 4 Schematic diagram of working state 1 of the driving circuit in the positive half cycle.

[0038] Figure 5 Schematic diagram of working state 2 of the driving circuit in the positive half cycle.

[0039] Figure 6 Schematic diagram of working state 3 of the driving circuit in the positive half cycle. DETAILED DESCRIPTION

[0040] The present application provides an energy feedback bipolar pulse drive circuit suitable for an excimer lamp, which is used to generate a pulse excitation voltage on the excimer lamp and simplify the structure of the existing pulse excitation drive circuit.

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0042] The specific steps for circuit implementation are:

[0043] Step 1: Using the equivalent circuit of the excimer lamp, offline measure the air gap equivalent capacitance Cd, the dielectric barrier equivalent capacitance Cg, and the discharge holding voltage Vth of the excimer lamp;

[0044] Step 2: Determine the operating frequency ω of the drive circuit according to the requirements of the excimer lamp, determine the resonant angular frequency ω of the load circuit based on the resonant circuit where the secondary winding of the transformer is located, determine the inductance of the secondary winding of the transformer, the primary and secondary coil turns Np1 / Np2 / Na1 of the transformer, and the voltage value of the DC voltage source;

[0045] Step 3: Calculate the voltage across the energy storage inductors L1 and L2 based on the rated power provided by the drive circuit, and determine the values ​​of the inductors L1 and L2 accordingly;

[0046] Step 4: Determine the primary-to-secondary turns ratio of the high-frequency transformer based on the discharge voltage of the excimer lamp and the current value of the energy storage inductor;

[0047] Step 5: Set the working timing of the two power switch tubes to form a driving signal.

[0048] Based on the above design steps, a set of typical parameters of the drive circuit are given below:

[0049] DC voltage source Vdc: 300V

[0050] Inductor L1, inductor L2: 4mH;

[0051] Capacitor C1, capacitor C2: 0.47nF;

[0052] Transformer T: rated frequency 100kHz, primary to secondary turns ratio 1:1:11.5; excitation inductance 300uH; leakage reactance converted to the secondary side of the transformer 1.5uH.

[0053] Operating frequency of the first power switch tube (Q1) and the second power switch tube (Q2): 100 kHz;

[0054] Duty cycle of the first power switch tube (Q1) and the second power switch tube (Q2): 10%;

[0055] Working status analysis

[0056] Specifically, the energy feedback bipolar pulse drive circuit for excimer lamps provided by the present invention has three operating modes in the positive half cycle. The operating states of the energy feedback bipolar pulse drive circuit for excimer lamps provided by the present invention are described below:

[0057] Working status 1:

[0058] Attachment Figure 4The diagram below shows operating state 1. In operating state 1, diode D1 is on, while diodes D2, D3, D4, D5, D6, and power switches Q1 and Q2 are off. A loop consisting of E → L1 → D1 → C1 → N1 is formed on the primary side of the transformer.

[0059] The main functions of this circuit are as follows:

[0060] The DC power supply E and the resonant inductor L1 charge the resonant capacitor C1. The voltage of the capacitor C1 continues to rise, and the charging current flows through the coil N1. The voltage of the DBD load changes.

[0061] Second circuit: A small current flows through coil N1. At this time, the current flowing through the DBD load is close to zero and the voltage of the DBD load changes slowly.

[0062] Working status 2:

[0063] Attachment Figure 5 The diagram below shows operating state 2. In operating state 2, diodes D1 and D2, along with power switch Q1, are on, while diodes D3, D6, and D7, along with power switch Q2, are off. Two loops are formed on the primary side of the transformer: the first loop consists of E → L1 → D1 → D2 → Q1; the second loop consists of C1 → D2 → Q1 → N1.

[0064] The main functions of each circuit are as follows:

[0065] First circuit: DC power supply E charges the resonant inductor L1, and the inductor current increases;

[0066] Second loop: A resonant loop is formed from C1 to N1 to DBD load. Since the value of C1, the transformer leakage reactance and the DBD complex equivalent capacitance are all small, a large pulse current will be formed in the secondary winding N1 of the transformer, which will form a pulse voltage with a high rise rate on the DBD load.

[0067] Working status 3:

[0068] Attachment Figure 6 Figure 3 is a schematic diagram of operating state 3. In operating state 3, only diode D3 is conducting, forming a loop consisting of N1 → D3 → E on the primary side of the transformer.

[0069] The main function of this circuit is to feed back the energy stored in the load on the excimer lamp to the DC power supply E.

[0070] As a preferred embodiment, the capacitance value of the first resonant capacitor (C1) is equal to the capacitance value of the second resonant capacitor (C2); the inductance value of the first resonant inductor (L1) is equal to the inductance value of the second resonant inductor (L2); the resistance value of the first absorption resistor is equal to the resistance value of the second absorption resistor; the operating frequency and duty cycle of the first power switch tube (Q1) and the second power switch tube (Q2) are equal, and the duty cycle is not higher than 0.1; the first diode (D1), the second diode (D2), the third diode (D3), the fourth diode (D4), the fifth diode (D5), and the sixth diode (D6) are all fast recovery diodes; the first power switch tube (Q1) and the second power switch tube (Q2) are both NMOS, wherein. The first ends of the first power switch tube (Q1) and the second power switch tube (Q2) are both NMOS drains; the second ends of the first power switch tube (Q1) and the second power switch tube (Q2) are both NMOS sources; the operating frequencies of the first power switch tube (Q1) and the second power switch tube (Q2) can be changed to adjust the output frequency of the power supply.

[0071] It should be noted that, in this specification, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

Claims

1. An energy feedback bipolar pulse drive circuit suitable for excimer lamps, characterized in that: include: A DC power supply, a first resonant inductor (L1), a second resonant inductor (L2), a first diode (D1), a second diode (D2), a third diode (D3), a fourth diode (D4), a fifth diode (D5), a sixth diode (D6), a seventh diode (D7), an eighth diode (D8), a first resonant capacitor (C1), a second resonant capacitor (C2), a first power switch tube (Q1), a second power switch tube (Q2), and a step-up transformer with a center tap; The anode of the DC power supply is respectively connected to the first end of the first resonant inductor (L1), the first end of the second resonant inductor (L2), the cathode of the fifth diode (D5), and the cathode of the sixth diode (D6); The second end of the first resonant inductor (L1) is connected to the anode of the first diode (D1); The cathode of the first diode (D1) is respectively connected to the anode of the second diode (D2) and the first end of the first resonant capacitor (C1); The cathode of the second diode (D2) is connected to the first end of the first power switch tube (Q1); The second end of the first resonant capacitor (C1) is connected to the anode of the third diode (D3) and the first end of the first primary winding of the transformer; The cathode of the DC power supply is respectively connected to the second end of the first power switch tube (Q1), the second end of the second power switch tube (Q2), the second end of the first primary winding of the transformer, and the first end of the second primary winding of the transformer; The second end of the second resonant inductor (L2) is connected to the anode of the fourth diode (D4); The cathode of the fourth diode (D4) is respectively connected to the anode of the seventh diode (D7) and the first end of the second resonant capacitor (C2); The cathode of the seventh diode (D7) is connected to the first end of the second power switch tube (Q2); The second end of the second resonant capacitor (C2) is respectively connected to the anode of the eighth diode (D8) and the second end of the second primary winding of the transformer; The first end and the second end of the secondary winding of the transformer are respectively connected to the two ends of the excimer lamp; The capacitance value of the first resonant capacitor (C1) is equal to the capacitance value of the second resonant capacitor (C2); The inductance value of the first resonant inductor (L1) is equal to the inductance value of the second resonant inductor (L2).

2. The energy feedback bipolar pulse drive circuit suitable for an excimer lamp according to claim 1, characterized in that: The operating frequency and duty cycle of the first power switch tube (Q1) and the second power switch tube (Q2) are equal, and the duty cycle is not higher than 0.

1.

3. The energy feedback bipolar pulse drive circuit suitable for an excimer lamp according to claim 1, characterized in that: The operating phases of the first power switch tube (Q1) and the second power switch tube (Q2) differ by 180 degrees.

4. An energy feedback bipolar pulse drive circuit suitable for an excimer lamp according to any one of claims 1 to 3, characterized in that: The first diode (D1), the second diode (D2), the third diode (D3), the fourth diode (D4), the fifth diode (D5), and the sixth diode (D6) are all fast recovery diodes.

5. An energy feedback bipolar pulse drive circuit suitable for an excimer lamp according to any one of claims 1 to 3, characterized in that: The first power switch tube (Q1) and the second power switch tube (Q2) are both NMOS, wherein the first ends of the first power switch tube and the second power switch tube (Q2) are both drains of the NMOS; and the second ends of the first power switch tube (Q1) and the second power switch tube (Q2) are both sources of the NMOS.

6. An energy feedback bipolar pulse drive circuit suitable for an excimer lamp according to any one of claims 1 to 3, characterized in that: The first power switch tube (Q1) and the second power switch tube (Q2) can be changed to adjust the output frequency of the power supply.

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