A bipolar high repetition frequency high voltage nanosecond pulse generation circuit and method

Abstract

The invention discloses a bipolar high repetition frequency high-voltage nanosecond pulse generating circuit and method, wherein each capacitor in the primary side of a pulse power supply main circuit is charged according to a preset charging voltage and charging polarity; a control unit transmits a control signal to a capacitor charging module and the primary side of the pulse power supply main circuit; the control unit sends a specific trigger pulse to trigger the primary side of the pulse power supply main circuit to discharge, thereby forming an initial pulse voltage; the initial pulse voltage acts on a multi-winding saturable pulse transformer to charge a secondary capacitor; the pulse voltage amplitude is increased through voltage conversion and pulse compression on the secondary side of the pulse power supply main circuit, thereby forming a nanosecond pulse voltage; after outputting a pulse voltage, the control unit switches the states of each semiconductor switch on the primary side of the pulse power supply main circuit according to a preset strategy, outputs the next pulse voltage, and the primary capacitor corresponding to the previous output pulse is in a charging state, thereby cyclically outputting bipolar high repetition frequency high-voltage nanosecond pulses.

Description

Technical Field

[0001] The invention belongs to the field of pulse power, and in particular to a bipolar high repetition frequency high voltage nanosecond pulse generation circuit and method. Background Art

[0002] With the development of pulse power technology, the application field of pulse power has gradually expanded from military to civilian use, such as plasma disinfection and sterilization, waste gas treatment, etc. The low-temperature plasma generated by high-voltage pulse discharge has significant advantages such as macroscopic temperature close to room temperature, high activity and good stability. Domestic and foreign studies have shown that the key parameters of low-temperature plasma (such as electron density and active particle concentration) are closely related to the pulse voltage waveform. Increasing the pulse frequency (above hundreds of kilohertz) can make full use of the discharge memory effect caused by residual excited state particles, which is beneficial to enhancing the discharge stability and intensity; using overvoltage excitation with a pulse time scale of nanoseconds to generate plasma is beneficial to increasing electron energy and active particle concentration; using bipolar pulses to excite plasma is beneficial to enhancing the local electric field strength. Therefore, the civilian and scientific research fields of pulse power technology urgently need high-performance bipolar high repetition rate high-voltage nanosecond pulse power supplies.

[0003] The output capacity of the pulse power supply depends largely on the switching technology used. In order to generate bipolar high repetition rate high voltage nanosecond pulses, the switch needs to have the ability of bidirectional conduction, high frequency operation, and fast switching speed. Commonly used pulse power switches include: gas switch, magnetic switch, semiconductor switch (MOSFET, IGBT, thyristor, thyristor, etc.). Among them, although the gas switch has strong conduction ability, large amount of transferred charge, and high working voltage, its repetition frequency working ability is weak, usually less than 100 Hz. Although the magnetic switch has bidirectional conduction ability, the switching speed is usually in the order of 100 nanoseconds. Semiconductor switches have full control or half control capabilities, high operating frequency, and can generate a variety of complex waveforms, but the operating voltage is low (usually not more than 5 kilovolts). Therefore, in order to generate bipolar high repetition rate high voltage nanosecond pulses, it is necessary to combine multiple switching technologies and design a reasonable circuit topology, which is very difficult. At present, several circuit topologies for generating bipolar repetition frequency high-voltage nanosecond pulses have been proposed at home and abroad, but they all have low repetition frequency (usually in the range of several kilohertz to tens of kilohertz), low voltage amplitude (usually less than ten kilovolts), and pulse width cannot reach the order of hundreds of nanoseconds. At the same time, traditional bipolar repetition frequency nanosecond pulse power supplies usually use semiconductor devices as switching devices, which are prone to heat, limiting the pulse repetition frequency, or can only output a limited number of bipolar high repetition frequency high-voltage nanosecond pulses in burst mode. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a bipolar high repetition rate high voltage nanosecond pulse generation circuit and method, which can solve the bottleneck problems of low output voltage amplitude and low pulse repetition frequency of the traditional bipolar repetition rate nanosecond pulse generation method.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A bipolar high repetition frequency high voltage nanosecond pulse generating circuit,

[0007] It includes a control unit, a high-power fast capacitor charging module, a primary side of a pulse power supply main circuit, a multi-winding saturable pulse transformer and a secondary side of a pulse power supply main circuit;

[0008] The output end of the high-power fast capacitor charging module is connected to the input end of the primary side of the pulse power supply main circuit, the output end of the primary side of the pulse power supply main circuit is connected to the input end of the multi-winding saturable pulse transformer, the output end of the multi-winding saturable pulse transformer is connected to the input end of the secondary side of the pulse power supply main circuit, and the control unit is respectively connected to the power fast capacitor charging module and the primary side of the pulse power supply main circuit.

[0009] Preferably, it also includes a low-voltage DC power supply, which is connected to the high-power fast capacitor charging module for power supply.

[0010] Preferably, the number of the high-power fast capacitor charging modules is not less than three.

[0011] Preferably, the primary side of the pulse power supply main circuit includes a plurality of power output units, each of which includes a primary capacitor and an anti-parallel semiconductor switch;

[0012] The primary capacitor is connected in parallel to the positive and negative electrodes of the high-power fast capacitor charging module, the positive electrode of the high-power fast capacitor charging module is connected to one end of an anti-parallel semiconductor switch, the other end of the anti-parallel semiconductor switch is connected to one end of the primary winding of a multi-winding saturable pulse transformer, and the other end of the primary winding is connected to the negative electrode of the power fast capacitor charging module.

[0013] Furthermore, the semiconductor switch includes a first diode, a second diode and an IGBT, the anode of the first diode and the emitter of the IGBT are connected to the anode of the high-power fast capacitor charging module, the cathode of the first diode is connected to the anode of the second diode and the collector of the IGBT, the cathode of the second diode is connected to one end of the primary winding in the multi-winding saturable pulse transformer, and the base of the IGBT is connected to the control unit.

[0014] Preferably, the secondary side of the pulse power supply main circuit includes a secondary capacitor C s2-1 , secondary capacitor Cs2-2 , secondary capacitor C s3-1 , secondary capacitor C s3-2 , magnetic switch MS-1, magnetic switch MS-2 and anti-parallel diode;

[0015] Secondary capacitor C s2-1 Connected in parallel to the secondary winding W of the multi-winding saturable pulse transformer 2 On the secondary capacitor C s2-1 and the secondary winding W 2 One end of the secondary capacitor C is connected in series s2-2 , secondary capacitor C s2-1 and the secondary capacitor C s2-2 A magnetic switch MS-1 is connected in parallel on it;

[0016] Secondary capacitor C s3-1 Connected in parallel to the secondary winding W of the multi-winding saturable pulse transformer 3 On the secondary capacitor C s3-1 and the secondary winding W 3 One end of the secondary capacitor C is connected in series s3-2 , secondary capacitor C s3-1 and the secondary capacitor C s3-2 A magnetic switch MS-2 is connected in parallel on it;

[0017] One end of the magnetic switch MS-2 is connected to one end of the anti-parallel diode, the other end of the anti-parallel diode is connected to one end of the discharge low-temperature plasma load DS, and the other end of the discharge low-temperature plasma load DS is connected to the magnetic switch MS-1 and the secondary winding W 2 one end.

[0018] Preferably, the secondary side of the pulse power supply main circuit includes a secondary capacitor C s2-1 , secondary capacitor C s2-2 , secondary capacitor C s3-1 , secondary capacitor C s3-2 , Charging inductor L c1 , Charging inductor L c2 , Charging inductor L c3 , Charging inductor L c4 , magnetic switch MS-1, magnetic switch MS-2 and anti-parallel diode;

[0019] Charging inductor L c1 Connected in series to the secondary winding W of the multi-winding saturable pulse transformer 2 On the secondary capacitor C s2-1 Connected in parallel to the secondary winding W of the multi-winding saturable pulse transformer 2 and charging inductor L c1 , secondary capacitor C s2-1 and charging inductor L c1 One end of the secondary capacitor C is connected in seriess2-2 , secondary capacitor C s2-1 There is a magnetic switch MS-1 in parallel with the secondary capacitor C s2-1 and the secondary capacitor C s2-2 There is a charging inductor L in parallel c2 ;

[0020] Charging inductor L c3 Connected in series to the secondary winding W of the multi-winding saturable pulse transformer 3 On the secondary capacitor C s3-1 Connected in parallel to the secondary winding W of the multi-winding saturable pulse transformer 3 and charging inductor L c3 , secondary capacitor C s3-1 and charging inductor L c3 One end of the secondary capacitor C is connected in series s3-2 , secondary capacitor C s3-1 There is a magnetic switch MS-2 in parallel with the secondary capacitor C s3-1 and the secondary capacitor C s3-2 There is a charging inductor L in parallel c4 ;

[0021] Secondary capacitor C s3-2 One end of the anti-parallel diode is connected to one end of the anti-parallel diode, the other end of the anti-parallel diode is connected to one end of the discharge low-temperature plasma load DS, and the other end of the discharge low-temperature plasma load DS is connected to the magnetic switch MS-1 and the secondary winding W 2 The magnetic switch MS-1 and the magnetic switch MS-2 are wound on the same magnetic core, and the same-named ends of the magnetic switch MS-1 and the magnetic switch MS-2 are connected to the secondary capacitor C s3-1 and the secondary capacitor C s2-1 superior.

[0022] A method for generating bipolar high repetition frequency high-voltage nanosecond pulses includes the following processes: a low-voltage DC power supply supplies power to a high-power fast capacitor charging module, and charges each capacitor in the primary side of a pulse power supply main circuit according to a preset charging voltage and charging polarity; a control unit transmits a control signal to the capacitor charging module and the primary side of the pulse power supply main circuit;

[0023] The control unit sends out a specific trigger pulse, which triggers the primary side of the pulse power supply main circuit to discharge and form an initial pulse voltage;

[0024] The initial pulse voltage acts on the multi-winding saturable pulse transformer to charge the secondary capacitor; through the voltage conversion and pulse compression on the secondary side of the pulse power supply main circuit, the pulse voltage amplitude is increased to form a nanosecond pulse voltage, which acts on the discharge low-temperature plasma load;

[0025] After outputting a pulse voltage, the control unit switches the states of the semiconductor switches on the primary side of the pulse power supply main circuit according to a preset strategy and outputs the next pulse voltage. During this period, the primary capacitor corresponding to the previous output pulse is in a charging state, and bipolar high repetition rate high-voltage nanosecond pulses are output cyclically.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects:

[0027] A bipolar high repetition frequency high-voltage nanosecond pulse generating circuit of the present invention solves the bottleneck problems of low output voltage amplitude and low pulse repetition frequency of the traditional bipolar repetition frequency nanosecond pulse generating method by setting multi-channel pulse delay trigger time base superposition, multi-winding saturable pulse transformer and synchronous saturation magnetic switch. By adopting the multi-channel pulse delay trigger time base superposition mode, the primary main capacitor charging time is extended, the output pulse repetition frequency is increased, and compared with the traditional H-bridge circuit, the loss of the semiconductor switch is reduced, and the heating of the semiconductor switch is reduced; by using a multi-winding saturable pulse transformer and a synchronous saturation magnetic switch, the saturation directions of the saturable transformer and the magnetic switch are opposite during the output of two adjacent pulses, so as to realize bipolar pulse generation; by adopting a multi-winding saturable pulse transformer, multiple capacitor voltages are formed in the output pulse stage and superimposed in sequence, so as to improve the output pulse voltage amplitude; by having modular expansion capability, 3 units are used as a subsystem for expansion (such as expansion to 6 units), and only the timing complexity of the trigger loop needs to be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a block diagram of a bipolar high repetition frequency high voltage nanosecond pulse generating circuit.

[0029] Figure 2 The schematic diagram of the bipolar repetition frequency nanosecond pulse generation circuit (taking 3 units as an example, structure 1).

[0030] Figure 3 The circuit principle of bipolar repetition frequency nanosecond pulse generation (taking 3 units as an example, structure 2).

[0031] Figure 4 The diagram shows the triggering sequence of the switch module when outputting bipolar repetition frequency nanosecond pulses, the pre-charge polarity of the main capacitor, and the polarity change rule of the main capacitor after output. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0033] like Figure 1As shown, the present invention provides a bipolar high repetition frequency high-voltage nanosecond pulse generating circuit, comprising a low-voltage DC power supply, a control unit, a high-power fast capacitor charging module, a primary side of a pulse power supply main circuit, a multi-winding saturable pulse transformer, a secondary side of a pulse power supply main circuit and a discharge low-temperature plasma load; the low-voltage DC power supply is connected to the high-power fast capacitor charging module for power supply, the output end of the high-power fast capacitor charging module is connected to the input end of the primary side of the pulse power supply main circuit, the output end of the primary side of the pulse power supply main circuit is connected to the input end of the multi-winding saturable pulse transformer, the output end of the multi-winding saturable pulse transformer is connected to the input end of the secondary side of the pulse power supply main circuit, the output end of the secondary side of the pulse power supply main circuit is connected to the input end of the discharge low-temperature plasma load, and the control unit is respectively connected to the power fast capacitor charging module and the primary side of the pulse power supply main circuit.

[0034] The advantage of the present invention is that it solves the bottleneck problems of low output voltage amplitude and low pulse repetition frequency of the traditional bipolar repetition frequency nanosecond pulse generation method through key technologies such as multi-channel pulse delay trigger time base superposition, multi-winding saturable pulse transformer, and synchronous saturation magnetic switch.

[0035] A bipolar high repetition frequency high-voltage nanosecond pulse generation method of the present invention is to power a high-power fast capacitor charging module through a low-voltage DC power supply, and charge each capacitor in the primary side of the pulse power supply main circuit according to a preset charging voltage and charging polarity. The control unit transmits the control signal to the capacitor charging module and the primary side of the pulse power supply main circuit by means of optical fiber or the like. The control unit sends a specific trigger pulse to trigger the primary side of the pulse power supply main circuit to discharge, forming an initial pulse voltage (usually a microsecond pulse). The initial pulse voltage acts on a multi-winding saturable pulse transformer to charge the secondary capacitor. Through the voltage conversion and pulse compression function of the secondary side of the pulse power supply main circuit, the pulse voltage amplitude is increased and the waveform is shaped to form a nanosecond pulse voltage, which acts on the discharge low-temperature plasma load. After outputting a pulse voltage (for example, a positive polarity pulse), the control unit switches the states of each semiconductor switch on the primary side of the pulse power supply main circuit according to a preset strategy, and outputs the next pulse voltage (for example, a negative polarity pulse), during which the primary capacitor corresponding to the previous output pulse is in a charging state. In this way, a continuous and stable output of bipolar high repetition frequency high-voltage nanosecond pulses is achieved.

[0036] Example 1

[0037] like Figure 2 , Figure 3 , Figure 4 The principle of the bipolar repetition frequency nanosecond pulse generation circuit (two structures), the triggering sequence of the switch module, the pre-charge polarity of the main capacitor, and the polarity change law of the main capacitor after output are shown.

[0038] Figure 2 The pulse transformer T will saturate during the pulse forming process. This circuit has fewer components, but the primary current is large and lasts for a long time. 1 , semiconductor switch S p1 , semiconductor switch S n1 The first group of units, the primary capacitor C 2 , semiconductor switch S p2 , semiconductor switch S n2 The second group of units, the primary capacitor C 3 , semiconductor switch S p3 , semiconductor switch S n3 The output terminals of the three groups of units are directly connected to a multi-winding saturable pulse transformer T (including a primary winding W 1 , 2 secondary windings W 2 and W 3 ) on the primary winding. 2 secondary windings W 2 and W 3 Wound on the same magnetic core. 4 secondary capacitors C s2-1 , C s2-2 , C s3-1 , C s3-2 Connected to the secondary winding W 2 and W 3 MS-1 and MS-2 are two synchronous saturation magnetic switches wound on the same magnetic core, which can ensure synchronous saturation after the same volt-second product. 1 and D 2 It is two fast recovery diode arrays connected between the magnetic switch MS-2 and the discharge low temperature plasma load DS. The semiconductor switch S is controlled by a multi-channel trigger signal generating unit. p1 , S n1 , S p2 , S n2 , S p3 , S n3 The on and off.

[0039] like Figure 2 As shown, a bipolar high repetition frequency high voltage nanosecond pulse generating circuit includes a low voltage DC power supply, a control unit, a high power fast capacitor charging module, a primary side of a pulse power supply main circuit, a multi-winding saturable pulse transformer, a secondary side of a pulse power supply main circuit and a discharge low temperature plasma load.

[0040] The low-voltage DC power supply is connected to the high-power fast capacitor charging module for power supply. The number of high-power fast capacitor charging modules is three. The primary side of the pulse power supply main circuit includes three power output units, each of which includes a primary capacitor, an anti-parallel semiconductor switch and a primary winding. The primary capacitor is connected in parallel to the positive and negative electrodes of the high-power fast capacitor charging module. The positive electrode of the high-power fast capacitor charging module is connected to one end of the anti-parallel semiconductor switch, one end of the anti-parallel semiconductor switch is connected to one end of the primary winding, and the other end of the primary winding is connected to the power fast capacitor charging module. The semiconductor switch includes a first diode, a second diode and an IGBT. The positive electrode of the first diode and the emitter of the IGBT are connected to the positive electrode of the high-power fast capacitor charging module, the negative electrode of the first diode is connected to the positive electrode of the second diode and the collector of the transistor, the negative electrode of the second diode is connected to one end of the primary winding, and the base of the IGBT is connected to the control unit.

[0041] The multi-winding saturable pulse transformer is connected to two secondary windings W 2 and W 3 , secondary winding W 2 A secondary capacitor C is connected in parallel s2-1 , secondary capacitor C s2-1 and the secondary winding W 2 One end of the secondary capacitor C is connected in series s2-2 , secondary capacitor C s2-1 and the secondary capacitor C s2-2 A magnetic switch MS-1 is connected in parallel.

[0042] Secondary Winding W 3 A secondary capacitor C is connected in parallel s3-1 , secondary capacitor C s3-1 and the secondary winding W 3 One end of the secondary capacitor C is connected in series s3-2 , secondary capacitor C s3-1 and the secondary capacitor C s3-2 A magnetic switch MS-2 is connected in parallel with one end of the magnetic switch MS-2, and an anti-parallel diode D 1 and D 2 One end of the anti-parallel diode D 1 and D 2 The other end of the discharge low-temperature plasma load DS is connected to one end of the discharge low-temperature plasma load DS, and the other end of the discharge low-temperature plasma load DS is connected to the magnetic switch MS-1 and the secondary winding W 2 One end of Figure 2 As shown, two magnetic switches are wound on the same magnetic core, and the same-name ends are connected to the secondary capacitors C s3-1 and the secondary capacitor C s3-2 superior.

[0043] Figure 2The working process of a bipolar high repetition frequency high voltage nanosecond pulse generating circuit is as follows:

[0044] (1) Initial state, C 1 , C 2 , C 3 The three primary capacitors are charged to positive, negative, and positive DC voltages, respectively. p1 , S n1 , S p2 , S n2 , S p3 , S n3 All six semiconductor switches are in the off state. Magnetic switches MS-1 and MS-2 are in the forward saturation state ( Figure 2 The middle is from top to bottom).

[0045] (2) Triggering semiconductor switch S p1 The switch is turned on, the primary capacitor C 1 The capacitor discharges to the pulse transformer T, and the secondary winding W 2 and W 3 A pulse voltage is generated on the winding, and the secondary capacitor C s2-1 and C s3-1 is charged to a positive voltage (positive at the top and negative at the bottom), and because the magnetic switches MS-1 and MS-2 are in a positive saturation state, the secondary capacitor C s2-2 and C s3-2 It is charged to a negative voltage (negative on top and positive on bottom). During this process, although the magnetic switches MS-1 and MS-2 are in a forward saturation state and the magnetic switches MS-1 and MS-2 have low impedance, there is still a certain voltage drop. If it is directly connected to the discharge low-temperature plasma load DS, there will be a pre-pulse with a higher amplitude. Fast recovery diode array D 1 and D 2 There is a certain conduction threshold, which can reduce the pre-pulse amplitude to a certain extent.

[0046] (3) When the secondary capacitor C s2-1 , secondary capacitor C s2-2 , secondary capacitor C s3-1 , secondary capacitor C s3-2 When charged to the highest voltage, the pulse transformer T is saturated and the primary winding W 1 , secondary winding W 2 , secondary winding W 3 Loss of strong electromagnetic coupling. Secondary capacitor C s2-1 and the secondary capacitor C s3-1 Respectively with W 2 and W 3 The residual inductance of the winding forms an LC oscillation, and the secondary capacitor C s2-1 and the secondary capacitor C s3-1 The voltage reverses rapidly and is superimposed on the secondary capacitor Cs2-2 and the secondary capacitor C s3-2 At the original voltage, a pulse voltage rising edge is formed on the discharge low-temperature plasma load DS, and the output voltage peak is theoretically the sum of the four capacitor voltages. At the peak voltage moment of the discharge low-temperature plasma load DS, the magnetic switches MS-1 and MS-2 are reversely saturated ( Figure 2 (from bottom to top), the secondary capacitor C s2-1 , secondary capacitor C s2-2 , secondary capacitor C s3-1 , secondary capacitor C s3-2 The charge is released through the magnetic switch MS-1 and the magnetic switch MS-2 to form the falling edge of the pulse voltage. The magnetic switch MS-1 and the magnetic switch MS-2 are two synchronous saturation magnetic switches wound on the same magnetic core, which can ensure synchronous saturation after the same volt-second product.

[0047] (4) After the pulse transformer T is saturated, the primary capacitor C 1 and the primary winding W 1 The residual inductance forms an LC oscillation, the forward current on the primary side increases again, and the semiconductor switch S is turned off at the current zero crossing point. p1 , at this time the primary capacitor C 1 The voltage is negative and has a magnitude lower than the pre-charge voltage.

[0048] (5) After a certain period of time, the primary capacitor C is triggered 2 (Pre-charged negative voltage) semiconductor switch S n2 When the switch is turned on, the working process is consistent with process (2), but the direction of the injected current is opposite, so a negative polarity pulse can be output on the discharge low-temperature plasma load DS.

[0049] (6) After the same interval, the primary capacitor C is triggered 3 (Pre-charged negative voltage) semiconductor switch S p3 When the switch is turned on, the working process is consistent with process (5), but the direction of the injected current is opposite, so a positive polarity pulse can be output on the discharge low-temperature plasma load DS.

[0050] (7) In the (5)-(6) stage, the high-power fast capacitor charging module charges the primary capacitor C 1 By analogy, the triggering order of the switch module when outputting bipolar repetition frequency nanosecond pulses, the pre-charge polarity of the main capacitor, and the polarity change law of the main capacitor after output are as follows: Figure 4 shown. Figure 4 The medium grey shading represents the trigger or capacitor voltage polarity change.

[0051] Example 2

[0052] Figure 3The pulse transformer T will not saturate during the pulse forming process. This circuit has more components, but the primary current is small and the duration is short. Primary capacitor C 1 , semiconductor switch S p1 , semiconductor switch S n1 The first group of units, the primary capacitor C 2 , semiconductor switch S p2 , semiconductor switch S n2 The second group of units, the primary capacitor C 3 , semiconductor switch S p3 , semiconductor switch S n3 The output ends of the three groups of units are directly connected to a multi-winding pulse transformer T (including a primary winding W 1 , 2 secondary windings W 2 , W 3 ) on the primary winding. 2 secondary windings W 2 and W 3 Wound on the same magnetic core. 4 secondary capacitors C s2-1 , C s2-2 , C s3-1 , C s3-2 Through the inductor L c1 and L c3 Connect to the secondary winding W 2 and W 3 MS-1 and MS-2 are two synchronous saturation magnetic switches wound on the same magnetic core, which can ensure synchronous saturation after the same volt-second product. 1 and D 2 It is two fast recovery diode arrays connected between the magnetic switch MS-2 and the discharge low temperature plasma load DS. c1 and charging inductor L c2 And the charging inductor L c3 and charging inductor L c4 To couple the inductors to each other, the turns ratio is 1:2, they are wound on the same core and in opposite directions.

[0053] like Figure 3 As shown, a bipolar high repetition frequency high voltage nanosecond pulse generating circuit includes a low voltage DC power supply, a control unit, a high power fast capacitor charging module, a primary side of a pulse power supply main circuit, a multi-winding saturable pulse transformer, a secondary side of a pulse power supply main circuit and a discharge low temperature plasma load.

[0054] The low-voltage DC power supply is connected to the high-power fast capacitor charging module for power supply. The number of high-power fast capacitor charging modules is three. The primary side of the pulse power supply main circuit includes three power output units, each of which includes a primary capacitor, an anti-parallel semiconductor switch and a primary winding. The primary capacitor is connected in parallel to the positive and negative electrodes of the high-power fast capacitor charging module. The positive electrode of the high-power fast capacitor charging module is connected to one end of the anti-parallel semiconductor switch, one end of the anti-parallel semiconductor switch is connected to one end of the primary winding, and the other end of the primary winding is connected to the power fast capacitor charging module. The semiconductor switch includes a first diode, a second diode and an IGBT. The positive electrode of the first diode and the emitter of the IGBT are connected to the positive electrode of the high-power fast capacitor charging module, the negative electrode of the first diode is connected to the positive electrode of the second diode and the collector of the transistor, the negative electrode of the second diode is connected to one end of the primary winding, and the base of the IGBT is connected to the control unit.

[0055] The multi-winding saturable pulse transformer is connected to two secondary windings W 2 and W 3 , charging inductance L c1 Connected in series to the secondary winding W of the multi-winding saturable pulse transformer 2 On the secondary capacitor C s2-1 Connected in parallel to the secondary winding W of the multi-winding saturable pulse transformer 2 and charging inductor L c1 , secondary capacitor C s2-1 and charging inductor L c1 One end of the secondary capacitor C is connected in series s2-2 , secondary capacitor C s2-1 There is a magnetic switch MS-1 in parallel with the secondary capacitor C s2-1 and the secondary capacitor C s2-2 There is a charging inductor L in parallel c2 .

[0056] Charging inductor L c3 Connected in series to the secondary winding W of the multi-winding saturable pulse transformer 3 On the secondary capacitor C s3-1 Connected in parallel to the secondary winding W of the multi-winding saturable pulse transformer 3 and charging inductor L c3 , secondary capacitor C s3-1 and charging inductor L c3 One end of the secondary capacitor C is connected in series s3-2 , secondary capacitor C s3-1 There is a magnetic switch MS-2 in parallel with the secondary capacitor C s3-1 and the secondary capacitor C s3-2 There is a charging inductor L in parallel c4 The secondary capacitor C s3-2 One end of the anti-parallel diode D 1and D 2 One end of the anti-parallel diode D 1 and D 2 The other end of the discharge low-temperature plasma load DS is connected to one end of the discharge low-temperature plasma load DS, and the other end of the discharge low-temperature plasma load DS is connected to the magnetic switch MS-1 and the secondary winding W 2 One end of Figure 3 As shown, two magnetic switches are wound on the same magnetic core, and the same-name ends are connected to the secondary capacitors C s3-1 and the secondary capacitor C s2-1 During the work, due to L c1 and L c2 and L c3 and L c4 The inductances are coupled to each other, so the overall magnetic flux can be offset, leaving only the inductance of the winding itself, and the charging speed is fast.

[0057] Figure 3 The circuit shown works as follows:

[0058] (1) Initial state, primary capacitance C 1 , primary capacitor C 2 , primary capacitor C 3 The three primary capacitors are charged to positive, negative, and positive DC voltages respectively, and the semiconductor switch S p1 , semiconductor switch S n1 , semiconductor switch S p2 , semiconductor switch S n2 , semiconductor switch S p3 , semiconductor switch S n3 All six semiconductor switches are in the off state.

[0059] (2) Triggering semiconductor switch S p1 The switch is turned on, the primary capacitor C 1 Discharge to the pulse transformer T, and the secondary winding W 2 and W 3 The pulse voltage is generated on the secondary capacitor C s2-1 and C s3-1 is charged to a positive voltage (positive on top and negative on bottom), the secondary capacitor C s2-2 and C s3-2 is charged to a negative voltage (negative on top and positive on bottom). c1 and L c2 and L c3 and L c4 The inductance is mutually coupled, so the overall magnetic flux can be offset, leaving only the inductance of the winding itself, and the charging speed is fast. c1 and L c2 and L c3 and L c4The impedance is low, but there is still a certain voltage drop. If it is directly connected to the discharge low-temperature plasma load DS, there will be a high-amplitude pre-pulse. Fast recovery diode array D 1 and D 2 There is a certain conduction threshold, which can reduce the pre-pulse amplitude to a certain extent.

[0060] (3) When the secondary capacitor C s2-1 , secondary capacitor C s2-2 , secondary capacitor C s3-1 , secondary capacitor C s3-2 When charged to the highest voltage, magnetic switches MS-1 and MS-2 are saturated. s2-1 and the secondary capacitor C s3-1 The residual inductances of MS-1 and MS-2 form LC oscillations respectively, and the secondary capacitor C s2-1 and the secondary capacitor C s3-1 The voltage reverses rapidly and is superimposed on the secondary capacitor C s2-2 and the secondary capacitor C s3-2 At the original voltage, a pulse voltage rise edge is formed on the discharge low-temperature plasma load DS, and the output voltage peak value is theoretically the sum of the four capacitor voltages. Magnetic switch MS-1 and magnetic switch MS-2 are two synchronous saturation magnetic switches wound on the same magnetic core, which can ensure synchronous saturation after the same volt-second product. During the discharge process, due to L c2 and L c4 The arrangement relationship of the same-name terminals, the overall magnetic flux can be superimposed, L c2 and L c4 The inductance is large, which can prevent the pulse current from passing through the transformer T and the inductor L c2 and inductor L c4 Release.

[0061] (4) Control the semiconductor switch S to turn off when the primary current crosses zero p1 , at this time the primary capacitor C 1 The voltage is negative and has a magnitude lower than the pre-charge voltage.

[0062] (5) After a certain period of time, the primary capacitor C is triggered 2 (Pre-charged negative voltage) semiconductor switch S n2 When the switch is turned on, the working process is consistent with process (2), but the direction of the injected current is opposite, so a negative polarity pulse can be output on the discharge low-temperature plasma load DS.

[0063] (6) After the same interval, the primary capacitor C is triggered 3 (Pre-charged negative voltage) semiconductor switch S p3When the switch is turned on, the working process is consistent with process (5), but the direction of the injected current is opposite, so a positive polarity pulse can be output on the discharge low-temperature plasma load DS.

[0064] (7) In the (5)-(6) stage, the high-power fast capacitor charging module charges the primary capacitor C 1 By analogy, the triggering order of the switch module when outputting bipolar repetition frequency nanosecond pulses, the pre-charge polarity of the main capacitor, and the polarity change law of the main capacitor after output are as follows: Figure 4 shown.

[0065] Compared with the traditional single capacitor and H-bridge circuit, this solution increases the output pulse repetition frequency by 3 times and reduces the power loss of semiconductor switches by 2 / 3. At the same time, the circuit has modular expansion capabilities and can be expanded by 3 units as a subsystem (for example, expanding to 6 units), only by increasing the timing complexity of the trigger loop.

Claims

1. A bipolar high repetition frequency high voltage nanosecond pulse generating circuit, characterized in that: It includes a control unit, a high-power fast capacitor charging module, a primary side of a pulse power supply main circuit, a multi-winding saturable pulse transformer and a secondary side of a pulse power supply main circuit; The output end of the high-power fast capacitor charging module is connected to the input end of the primary side of the pulse power supply main circuit, the output end of the primary side of the pulse power supply main circuit is connected to the input end of the multi-winding saturable pulse transformer, the output end of the multi-winding saturable pulse transformer is connected to the input end of the secondary side of the pulse power supply main circuit, the control unit is respectively connected to the high-power fast capacitor charging module and the primary side of the pulse power supply main circuit; the primary side of the pulse power supply main circuit includes a plurality of power output units, each of which includes a primary capacitor and an anti-parallel semiconductor switch; The primary capacitor is connected in parallel to the positive and negative electrodes of the high-power fast capacitor charging module, the positive electrode of the high-power fast capacitor charging module is connected to one end of an anti-parallel semiconductor switch, the other end of the anti-parallel semiconductor switch is connected to one end of the primary winding of a multi-winding saturable pulse transformer, and the other end of the primary winding is connected to the negative electrode of the high-power fast capacitor charging module; the secondary side of the pulse power supply main circuit includes a secondary capacitor C s2-1 , Secondary Capacitor C s2-2 , Secondary Capacitor C s3-1 , Secondary Capacitor C s3-2 , magnetic switch MS-1, magnetic switch MS-2 and anti-parallel diode; Secondary Capacitor C s2-1 Parallel connection in the secondary winding of a multi-winding saturable pulse transformer W 2, secondary capacitor C s2-1 and the secondary winding W One end of 2 is connected in series with a secondary capacitor C s2-2 , secondary capacitor C s2-1 and secondary capacitor C s2-2 There is a magnetic switch in parallel MS-1 ; Secondary Capacitor C s3-1 Connected in parallel to the secondary winding W3 of the multi-winding saturable pulse transformer, the secondary capacitor C s3-1 and the secondary winding W One end of 3 is connected in series with a secondary capacitor C s3-2 , secondary capacitance C s3-1 and secondary capacitor C s3-2 There is a magnetic switch in parallel MS-2 ; Magnetic switch MS-2 One end of the anti-parallel diode is connected to one end of the anti-parallel diode, and the other end of the anti-parallel diode is connected to the discharge low-temperature plasma load DS At one end, discharge low temperature plasma load DS The other end of the magnetic switch MS-1 and the secondary winding W 2 end.

2. A bipolar high repetition frequency high voltage nanosecond pulse generating circuit according to claim 1, characterized in that: It also includes a low-voltage DC power supply, which is connected to a high-power fast capacitor charging module for power supply.

3. A bipolar high repetition frequency high voltage nanosecond pulse generating circuit according to claim 1, characterized in that: The number of the high-power fast capacitor charging modules is no less than three.

4. A bipolar high repetition frequency high voltage nanosecond pulse generating circuit according to claim 1, characterized in that: The semiconductor switch includes a first diode, a second diode and an IGBT, wherein the anode of the first diode and the emitter of the IGBT are connected to the anode of the high-power fast capacitor charging module, the cathode of the first diode is connected to the anode of the second diode and the collector of the IGBT, the cathode of the second diode is connected to one end of the primary winding in the multi-winding saturable pulse transformer, and the base of the IGBT is connected to the control unit.

5. The bipolar high repetition frequency high voltage nanosecond pulse generating circuit according to claim 1, characterized in that: The secondary side of the pulse power supply main circuit includes a secondary capacitor C s2-1 , Secondary Capacitor C s2-2 , Secondary Capacitor C s3-1 , Secondary Capacitor C s3-2 , Charging inductor L c1 , Charging inductor L c2 , Charging inductor L c3 , Charging inductor L c4 , magnetic switch MS-1, magnetic switch MS-2 and anti-parallel diode; Charging inductor L c1 Connected in series to the secondary winding of a multi-winding saturable pulse transformer W 2, secondary capacitor C s2-1 Parallel connection in the secondary winding of a multi-winding saturable pulse transformer W 2 and charging inductor L c1 , secondary capacitor C s2-1 and charging inductor L c1 One end of the secondary capacitor is connected in series C s2-2 , secondary capacitor C s2-1 There is a magnetic switch in parallel MS-1 , secondary capacitor C s2-1 and secondary capacitor C s2-2 There is a charging inductor in parallel L c2 ; Charging inductor L c3 Connected in series to the secondary winding of a multi-winding saturable pulse transformer W 3, secondary capacitor C s3-1 Parallel connection in the secondary winding of a multi-winding saturable pulse transformer W 3 and charging inductor L c3 , secondary capacitor C s3-1 and charging inductor L c3 One end of the secondary capacitor is connected in series C s3-2 , secondary capacitor C s3-1 There is a magnetic switch in parallel MS-2 , secondary capacitor C s3-1 and secondary capacitor C s3-2 There is a charging inductor in parallel L c4 ; Secondary Capacitor C s3-2 One end of the anti-parallel diode is connected to one end of the anti-parallel diode, and the other end of the anti-parallel diode is connected to the discharge low-temperature plasma load DS At one end, discharge low temperature plasma load DS The other end of the magnetic switch MS-1 and the secondary winding W One end of 2; magnetic switch MS-1 and magnetic switch MS-2 Wound on the same core, magnetic switch MS-1 and magnetic switch MS-2 The same-name terminals are connected to the secondary capacitors C s3-1 and secondary capacitor C s2-1 superior.

6. A method for generating bipolar high repetition rate high voltage nanosecond pulses, executing the bipolar high repetition rate high voltage nanosecond pulse generating circuit as claimed in any one of claims 1 to 5, characterized in that: The process includes the following steps: a low-voltage DC power supply supplies power to a high-power fast capacitor charging module, and charges each capacitor in the primary side of the pulse power supply main circuit according to a preset charging voltage and charging polarity; a control unit transmits a control signal to the capacitor charging module and the primary side of the pulse power supply main circuit; The control unit sends out a specific trigger pulse, which triggers the primary side of the pulse power supply main circuit to discharge and form an initial pulse voltage; The initial pulse voltage acts on the multi-winding saturable pulse transformer to charge the secondary capacitor; through the voltage conversion and pulse compression on the secondary side of the pulse power supply main circuit, the pulse voltage amplitude is increased to form a nanosecond pulse voltage, which acts on the discharge low-temperature plasma load; After outputting a pulse voltage, the control unit switches the states of the semiconductor switches on the primary side of the pulse power supply main circuit according to a preset strategy and outputs the next pulse voltage. During this period, the primary capacitor corresponding to the previous output pulse is in a charging state, and bipolar high repetition rate high-voltage nanosecond pulses are output cyclically.

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