JP4824419B2 - Discharge device - Google Patents

Description

  The present invention applies a high voltage at which the transformer saturates to the transformer, causes one discharge to occur during the period until the transformer reaches saturation, and performs another discharge after the transformer reaches saturation. The present invention relates to a discharging device.

  Recently, techniques for deodorization, sterilization, decomposition of harmful gases, etc. have been applied by plasma generated by high voltage pulse discharge. To generate this plasma, a very narrow pulse of high voltage is applied. A high voltage pulse generation circuit that can be supplied is required.

  Therefore, conventionally, for example, a high voltage pulse generating circuit as shown in Patent Document 1 has been proposed. As shown in FIG. 9, the high voltage pulse generation circuit 200 includes a transformer 204, a first semiconductor switch 206, and a second semiconductor switch 208 connected in series to both ends of a DC power supply unit 202, and an anode of the first semiconductor switch 206. This is a very simple circuit in which a diode 210 is connected to the other end of the primary winding of the transformer 204, one end of which is connected to the terminal, and to the anode of the gate terminal of the first semiconductor switch 206.

  When the second semiconductor switch 208 is turned on, the first semiconductor switch 206 is also turned on, the voltage of the DC power supply unit 202 is applied to the primary winding of the transformer 204, and inductive energy is accumulated in the transformer 204. After that, when the second semiconductor switch 208 is turned off, the first semiconductor switch 206 is also turned off rapidly, so that a very narrow high voltage pulse that rises very rapidly in the secondary winding of the transformer 204 is generated, and the output terminal Higher voltage Vo can be taken out than 212 and 214.

  According to the high voltage pulse generation circuit 200, a high voltage Vo having a steep rise time and an extremely narrow pulse width is supplied with a simple circuit configuration without using a plurality of semiconductor switches to which a high voltage is applied. be able to.

JP 2004-72994 A

  By the way, it is conceivable that a reactor is connected between the output terminals 212 and 214 of the high voltage pulse generation circuit 200 described above to generate a discharge in the reactor. In particular, silent discharge is advantageous in that it can create a stable non-equilibrium plasma state without arc discharge, and there are few restrictions on the applied voltage waveform. As a silent discharge reactor, it is conceivable to use a reactor having a pair of electrodes and having a dielectric and a space interposed between the pair of electrodes. As the dielectric, for example, alumina is used.

  Here, the discharge action in the reactor 300 in which the dielectric 305 and the space are interposed between the pair of electrodes will be described with reference to FIGS.

  First, as shown in FIGS. 10 and 11, the reactor 300 includes a dielectric 305 having two alumina plates (an upper alumina plate 302 and a lower alumina plate 304) arranged on the upper and lower sides constituting the dielectric 305, and an upper A support plate 308 for keeping the space 306 formed between the alumina plate 302 and the lower alumina plate 304 constant, an upper electrode 310 disposed on the upper surface of the upper alumina plate 302, and a lower alumina plate 304 And a lower electrode 312 (see FIG. 11) provided on the lower surface.

  When this reactor 300 is shown by an equivalent circuit, as shown in FIG. 12, the capacitance Cc of the dielectric 305 by the upper alumina plate 302 and the lower alumina plate 304 and the capacitance Cg by the space 306 are connected in series. .

Although the voltage applied to the space 306 (space discharge voltage Vg) is unknown, if the voltage applied to the reactor 300 as a whole (output voltage Vo) and the voltage applied to the capacitance Cc (charge voltage Vc of the dielectric 305) are known, It can obtain | require from the relational expression.
Vg = Vo-Vc

The charge voltage Vc of the dielectric 305 is Q, and the current flowing through the reactor 300 is Io.
Vc = Q / Cc = (1 / Cc) × ∫Iodt
It becomes.

  Then, as shown in FIG. 12, the reactor 300 is connected between the output terminals 212 and 214 of the high voltage pulse generation circuit 200 to perform the above-described normal circuit operation, and after the first semiconductor switch 206 is turned off, the reactor As shown in FIG. 13, the waveform of the voltage applied to 300 (output voltage Vo) is a waveform in which the forward peak voltage Vp1 first appears between the reactors 300, and then the reverse peak voltage Vp2 appears. . The waveform of the voltage applied to the dielectric 305 (the charging voltage Vc of the dielectric 305) shows a waveform that becomes the forward peak voltage Vp when the forward peak voltage Vp1 of the output voltage Vo appears.

  On the other hand, the spatial discharge voltage Vg is clamped to a certain positive voltage Vg1 during the period of the forward output voltage Vo, as can be seen by plotting based on the above-described calculation formula, and the reverse output voltage Vo In the period, it is clamped to a certain negative voltage Vg2.

  Accordingly, when viewed in terms of an equivalent circuit, the space 306 of the reactor 300 has a configuration in which a series circuit 316 in which the anode terminals of two zener diodes 314a and 314b are connected to each other and a capacitance Cg are connected in parallel as shown in FIG. It becomes.

  Next, the movement of the voltage (output voltage Vo) applied to the reactor 300 will be described with reference to FIG.

  First, by turning on the second semiconductor switch 208, the first semiconductor switch 206 becomes conductive, a current flows through the exciting inductance of the transformer 204, and inductive energy is accumulated in the transformer 204. Thereafter, when the second semiconductor switch 208 is turned off at time t10, the current flowing in the exciting inductance of the transformer 204 is commutated to the reactor 300.

  In this initial stage, the current Ig flows through the capacitance Cg of the space 306 of the reactor 300 to charge the capacitance Cg (see the broken line P in FIG. 12), and when the discharge voltage is reached, the voltage of the space 306 is clamped (in order). The current Io flows through the series circuit 316 (see the broken line Q in FIG. 12). At this time, the dielectric 305 is also rapidly charged at the same time, and energy is accumulated in the dielectric 305.

  At the time t11 when the current Io flowing through the reactor 300 becomes zero, the charging of the dielectric 305 is completed, and at the same time, a part of the energy accumulated in the dielectric 305 is consumed by the discharge.

  After that, the current Io flows in the reverse direction, whereby the current Ig flows in the capacitance Cg of the space 306 of the reactor 300 and the capacitance is charged (see the broken line R in FIG. 12), and becomes a discharge voltage. At that time, the voltage in the space 306 is clamped (clamped at the discharge voltage Vg2 in the reverse direction), and the current Io flows through the series circuit 316 (see the broken line S in FIG. 12). At this time, a part of the energy remaining in the dielectric 305 is consumed by the discharge. The energy that is not consumed in the reactor 300 returns to the DC power supply unit 202 (see FIG. 9). As a result, the charging voltage Vc of the dielectric 305 becomes 0V.

  Therefore, in the high voltage pulse generation circuit 200 shown in FIG. 9, the dielectric 305 is connected by connecting the diode 318 in parallel with the first semiconductor switch 206 and with the cathode side of the first semiconductor switch 206 as the anode. When a discharge (dielectric barrier discharge) is performed in the reactor 300 having the above, excess energy that was not used for the discharge can be regenerated in the DC power supply unit 202.

  However, when the reactor 300 as shown in FIG. 10 that performs dielectric barrier discharge is driven by the high voltage pulse generation circuit 200, there is a problem that it is difficult to process the energy accumulated in the dielectric 305. As described above, there is a method of regenerating energy stored in the dielectric 305 to the DC power supply unit 202. However, there is a problem that the regenerative efficiency is low and does not contribute much to the efficiency of the power source.

  The present invention has been made in consideration of such problems, and with a simple circuit configuration, it is possible to effectively use, for example, energy stored in a dielectric of a reactor as discharge energy, and to improve power supply efficiency. An object of the present invention is to provide a discharge device capable of performing

  Another object of the present invention is that, in addition to the above-mentioned matters, it is possible to realize steep discharge, and it is possible to apply pulse plasma technology at atmospheric pressure (gas treatment, etc.) and generate high-density plasma. It is to provide a discharge device.

  In addition to the above-described matters, another object of the present invention is to make it possible to use a discharge generated before the steep discharge as a preliminary discharge, and to generate a wide-range and high-density plasma. To provide an apparatus.

Discharge device according to the present invention includes a transformer and at least one semiconductor switch connected in series saturable type across the power supply unit, and said coupled to the secondary side of the transformer reactor, said reactor, A pair of electrodes, two dielectrics interposed between the pair of electrodes, and a space interposed between the two dielectrics, the secondary side of the transformer as the semiconductor switch is turned on A first discharge in the space of the reactor due to a unidirectional current flowing in the first and a second current in the space of the reactor due to a reverse current flowing in the secondary side of the transformer as the transformer is saturated. It is characterized by generating discharge.

  Thereby, the energy accumulated in the reactor can be effectively used as the discharge energy, and the power supply efficiency can be improved. In addition, a steep discharge can be realized as the second discharge, and it is possible to apply a pulsed plasma technique at atmospheric pressure (gas treatment or the like) and generate a high-density plasma. Furthermore, the first discharge that occurs before the steep second discharge can be used as a preliminary discharge. In general, as a means for generating a uniform glow-like discharge in which a streamer is diffused, there is a method using a preionization pulse discharge used in a discharge excitation excimer laser device. A wide range of high-density plasma can be generated by using discharge.

In particular, the reactor may have a pair of electrodes, two dielectrics interposed between the pair of electrodes, and a space interposed between the two dielectrics . In this case, the energy accumulated in the dielectric of the reactor by the first discharge is effectively converted into discharge energy and generated as the second discharge.

Further, in the present invention, the power supply unit has a capacitor to which a power supply voltage is supplied, the discharge of the capacitor is performed by the one direction of the current flowing through the primary side of the transformer due to the turn-on of the semiconductor switches, the the reverse current flowing through the transduction of regenerative energy due to the resonance of the primary side of the transformer after transformer saturation on the primary side of the transformer may be recharge to the capacitor is carried out.

  This is a method of dealing with the energy stored in the capacitor. When the transformer is saturated with charge remaining in the capacitor (for example, the capacitor is at a positive voltage), the capacitor continues to discharge and the capacitor is reversed. The capacitor is charged in the direction and becomes a negative voltage. Further, when resonance is performed on the primary side of the transformer, the energy remaining in the capacitor is transmitted to the capacitor by regeneration, and the capacitor is charged again in one direction to become a positive voltage again. That is, since the energy remaining in the capacitor is regenerated by the resonance phenomenon on the primary side of the transformer, the energy regenerated in the capacitor can be used for the next discharge.

  In this case, a diode may be connected in parallel with the semiconductor switch and in a forward direction with respect to a current in a reverse direction due to transmission of the regenerative energy to the capacitor. As a result, when the energy remaining in the capacitor is regenerated using the resonance phenomenon, the current accompanying the regeneration bypasses the semiconductor switch and flows through the diode, so that the capacitor can be recharged efficiently. Can do.

  In the present invention, a second diode may be connected in parallel with the primary winding of the transformer and in a forward direction with respect to a current in a reverse direction due to transmission of the regenerative energy to the capacitor.

  In this case, since the reverse current regenerated using the resonance phenomenon flows bypassing the primary winding of the transformer, the capacitor can be recharged smoothly, and the charging efficiency of the capacitor Can be further improved.

  In the present invention, a third diode may be connected in series with the semiconductor switch and in a forward direction with respect to a unidirectional current flowing on the primary side of the transformer after the transformer is saturated.

  In this case, since the current in the reverse direction accompanying regeneration flows through the diode connected in parallel with the semiconductor switch without turning off the semiconductor switch, the configuration of the circuit (control circuit) for driving and controlling the semiconductor switch is configured. This can be simplified and is advantageous in reducing the cost.

  In the present invention, a fourth diode may be connected in parallel to the capacitor and in a forward direction with respect to the current in one direction. In this case, the residual charge of the capacitor can be consumed by the fourth diode. Note that a resistor may be connected in series with the fourth diode in order to efficiently consume the residual charge.

  In the present invention, a reset circuit for resetting the saturation of the saturated transformer may be provided on the secondary side of the transformer. Thereby, the cycle of the first discharge → the second discharge can be repeatedly performed, and deodorization, sterilization, decomposition of harmful gas, purification, and the like can be performed efficiently.

  As described above, according to the discharge device of the present invention, the following effects can be obtained.

  (1) With a simple circuit configuration, energy stored in, for example, a dielectric of the reactor can be effectively used as discharge energy, and power supply efficiency can be improved.

  (2) A steep discharge can be realized, and application of pulsed plasma technology at atmospheric pressure (gas treatment, etc.) and generation of high-density plasma are possible.

  (3) The discharge generated in the previous stage of the abrupt discharge can be used as a preliminary discharge, and a wide range and high density plasma can be generated.

  Hereinafter, an embodiment of a discharge device according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the discharge device 10 according to the present embodiment includes a high voltage pulse generation circuit 12 and a reactor 14.

  The high voltage pulse generation circuit 12 includes a DC power supply unit 16 (power supply voltage Vcd), a transformer 22 and a semiconductor switch 24 connected in series between the + terminal 18 and the − terminal 20 of the DC power supply unit 16.

  The DC power supply unit 16 is connected between a capacitor 26 connected between the + terminal 18 and the − terminal 20, a capacitor charger 28 that charges the capacitor 26, and between the capacitor charger 28 and the + terminal 18. And an inductor 30. The predetermined power supply voltage Vcd that is the voltage across the capacitor 26 is set to a voltage sufficient to saturate the transformer 22.

  The transformer 22 has a primary winding 32 and a secondary winding 34, and a high voltage is extracted from the first output terminal 36 and the second output terminal 38 of the secondary winding 34 of the transformer 22. . That is, the reactor 14 is connected between the first output terminal 36 and the second output terminal 38 of the secondary winding 34. In addition, the winding start of the primary winding 32 and the secondary winding 34 is determined so that the primary side and the secondary side of the transformer 22 have a positive polarity.

  An anode terminal of the semiconductor switch 24 is connected to one end 40 of the primary winding 32 in the transformer 22, and a first diode 42 is connected in parallel to the semiconductor switch 24. The first diode 42 has an anode terminal connected to the cathode terminal of the semiconductor switch 24 and a cathode terminal connected to the anode terminal of the semiconductor switch 24.

  A second diode 44 is connected in parallel to the primary winding 32 of the transformer 22. The second diode 44 has an anode terminal connected to one end 40 of the primary winding 32 (an anode terminal of the semiconductor switch 24) and a cathode terminal connected to the other end 46 of the primary winding 32. Note that the second diode may be omitted. FIG. 7 shows an example in which the second diode is omitted for reference.

  As the semiconductor switch 24, a current control type device or a self-extinguishing type or a commutation extinguishing type device can be used. In this embodiment, the withstand voltage against the rate of voltage increase (dv / dt) at the time of turn-off is improved. An SI thyristor that is extremely large and has a high voltage rating is used. A control circuit 48 for controlling ON / OFF of the SI thyristor is connected between the gate terminal and the cathode terminal of the semiconductor switch 24.

  On the other hand, the reactor 14 is connected between the first output terminal 36 and the second output terminal 38 of the transformer 22 in the high voltage pulse generation circuit 12 and has the same configuration as that of FIGS. 10 and 11. That is, the interval between the dielectric 305 having two alumina plates (upper alumina plate 302 and lower alumina plate 304) arranged on the upper and lower sides and the space 306 formed between the upper alumina plate 302 and the lower alumina plate 304 is set. It has a support plate 308 for keeping constant, an upper electrode 310 disposed on the upper surface of the upper alumina plate 302, and a lower electrode 312 provided on the lower surface of the lower alumina plate 304.

  When the reactor 14 is shown by an equivalent circuit, a capacitance Cc by a dielectric 305 (upper alumina plate 302 and lower alumina plate 304) and a capacitance Cg by a space 306 are connected in series, and two Zener diodes 50a and 50b are further connected. The series circuit 52 in which the anode terminals are connected to each other is connected in parallel to the capacitance Cg.

A discharge apparatus 10 according to this embodiment, as the transformer 22, using a saturable transformer, further, by way of the current flowing through the secondary side of the transformer 22 with the turn-on of the semiconductor switch 24, the reactor 14 The first discharge (forward discharge) is generated at 1 (first mode M1), and then the second discharge (in the reactor 14 is caused by the reverse current flowing to the secondary side of the transformer 22 as the transformer 22 is saturated). (Reverse discharge) is generated (second mode M2).

  Here, the circuit operation of the discharge device 10 according to the present embodiment will be described with reference to FIGS.

  2 shows the output voltage Vo applied to the secondary side of the transformer 22, in particular, the reactor 14, the voltage Vg applied to the space 306 of the reactor 14, the voltage Vc applied to the dielectric 305 of the reactor 14, It is a figure which shows the waveform of the output current Io which flows into the reactor 14, and omits the waveform of the voltage of the primary side of the transformer 22, and an electric current.

  FIG. 3 is a diagram showing waveforms of the primary side of the transformer 22, in particular, the voltage Vcd across the capacitor 26, the current Icd flowing through the capacitor 26, the current Is flowing through the semiconductor switch 24, and the current Id1 flowing through the first diode 42. The voltage and current waveforms on the secondary side of the transformer 22 are omitted.

  First, from the stage where the capacitor 26 of the DC power supply unit 16 is charged with a predetermined power supply voltage Vcd, when the semiconductor switch 24 is turned on at time t0 in FIGS. 2 and 3, the first mode M1 is started. A voltage across the capacitor 26, that is, a predetermined power supply voltage Vcd sufficient to saturate the transformer 22 is applied to the transformer 22. On the primary side of the transformer 22, the positive terminal 18 of the capacitor 26 → the primary winding 32 of the transformer 22. → Semiconductor switch 24 → Current Icd flows through the first path 54 (see FIG. 1) of the negative terminal 20 of the capacitor 26.

  Further, on the secondary side of the transformer 22, the secondary winding 34 of the transformer 22 → the first output terminal 36 → the dielectric 305 (capacitance Cc) → the space 306 (capacitance Cg) → the second output terminal 38 → the secondary winding. The output current Io (see FIG. 2) flows through 34 second paths 56 (see FIG. 1). When the output current Io flows through the second path 56, the output voltage Vo (see FIG. 2) between the first output terminal 36 and the second output terminal 38 of the reactor 14 increases. Note that it takes some time for the output voltage Vo to reach the peak value due to the influence of the leakage inductance of the transformer 22.

  In the first mode M1, the current Io flows through the capacitance Cg of the space 306 of the reactor 14 to charge the capacitance Cg. When the discharge voltage is reached, the voltage of the space 306 is clamped (at the forward discharge voltage). Clamp: forward discharge), the current Io flows through the series circuit 52. At this time, the dielectric 305 (the upper alumina plate 302 and the lower alumina plate 304) is rapidly charged at the same time, and energy is accumulated in the dielectric 305.

  At time t1 when the output voltage Vo reaches the peak value, the transformer 22 is saturated, and the secondary side inductance of the transformer 22 is rapidly reduced. As a result, as shown in FIG. 4, this time, the output current Io flows from the dielectric 305 of the reactor 14 charged to a high voltage toward the magnetically saturated transformer 22 (second mode M2: see FIG. 2). . That is, in the second mode M2, the dielectric 305 (capacitance Cc) → the first output terminal 36 → the secondary winding 34 of the transformer 22 → the second electromotive force due to the electric charge accumulated in the dielectric 305 of the reactor 14 2 Output terminal 38 → space 306 (capacitance Cg) → dielectric 305 (capacitance Cc) is a third path 58, that is, the output current Io is abrupt in a path opposite to the second path 56 (see FIG. 1). Flowing into.

  As a result, the capacitance Cg of the space 306 of the reactor 14 is charged, and the voltage of the space 306 is clamped when the discharge voltage is reached (clamped by a reverse discharge voltage: reverse discharge). Due to the discharge (reverse discharge) due to the output current -Io in the reverse direction, the voltage Vc due to the energy remaining in the dielectric 305 is applied to the space 306, and the output voltage Vo sharply decreases. By this reverse discharge, all the energy remaining in the dielectric 305 is consumed.

  On the other hand, on the primary side of the transformer 22, as shown in FIG. 5, from the time t0 when the semiconductor switch 24 is turned on, the positive terminal 18 of the capacitor 26 → the primary winding 32 of the transformer 22 → the semiconductor switch 24 → the negative terminal of the capacitor 26. A current Icd (see FIG. 3) flows through the fourth path 60 indicated by 20, and the voltage Vcd across the capacitor 26 (see FIG. 3) gradually decreases. That is, the capacitor 26 is unidirectionally discharged.

  After that, when the transformer 22 is saturated with the charge remaining in the capacitor 26 (the capacitor 26 is at a positive voltage, for example) (after time t1), the capacitor 26 continues to be discharged, and the capacitor 26 is charged in the reverse direction. When the current Icd reaches the peak value, the voltage Vcd across the capacitor 26 becomes almost zero.

  Thereafter, when resonance (LC resonance due to the capacitance and wiring of the capacitor 26 and the inductance of the primary winding 32) is performed on the primary side of the transformer 22, energy remaining in the capacitor 26 is transmitted to the capacitor 26 by regeneration. As a result of this regeneration, a current Icd flows through the fifth path indicated by the negative terminal 20 of the capacitor 26 → the first diode 42 → the second diode 44 → the positive terminal 18 of the capacitor 26, and the capacitor 26 is charged again in one direction, and again. Positive voltage.

  Note that the semiconductor switch 24 is turned off by the control circuit 48 after the time point t2 when the current Icd becomes zero.

Thus, in the discharge device 10 according to the present embodiment, as the transformer 22, using a saturable transformer, further, by way of the current flowing through the secondary side of the transformer 22 with the turn-on of the semiconductor switch 24 The first discharge (forward discharge) is generated in the reactor 14, and then the second discharge (reverse discharge) is generated in the reactor 14 due to the reverse current flowing to the secondary side of the transformer 22 as the transformer 22 is saturated. Therefore, the energy accumulated in the reactor 14 by the first discharge can be efficiently converted into the discharge energy and used as the second discharge, and the power supply efficiency can be improved.

  In addition, a steep discharge can be realized as the second discharge, and it is possible to apply a pulsed plasma technique at atmospheric pressure (gas treatment or the like) and generate a high-density plasma.

  Furthermore, the first discharge that occurs before the steep second discharge can be used as a preliminary discharge. In general, as a means for generating a uniform glow-like discharge in which a streamer is diffused, there is a method using a preionization pulse discharge used in a discharge excitation excimer laser device. A wide range of high-density plasma can be generated by using discharge.

  In particular, in the discharge device 10 according to this embodiment, as shown in FIG. 3, when resonance occurs on the primary side of the transformer 22 after saturation of the transformer 22, the energy remaining in the capacitor 26 is regenerated. Is transmitted to the capacitor 26, and the capacitor is charged again in one direction to become a positive voltage again. That is, since the energy remaining in the capacitor 26 is regenerated by the resonance phenomenon on the primary side of the transformer 22, the energy regenerated in the capacitor 26 can be used for the next discharge.

  Further, since the first diode 42 is connected in parallel to the semiconductor switch 24 and in the forward direction with respect to the reverse current due to the transmission of the regenerative energy to the capacitor 26, the energy remaining in the capacitor 26 is reduced. When regeneration is performed using the resonance phenomenon, the reverse current accompanying the regeneration bypasses the semiconductor switch 24 and flows through the first diode 42. Therefore, the capacitor 26 can be efficiently recharged. .

  Further, since the second diode 44 is connected in parallel to the primary winding of the transformer 22 and in the forward direction with respect to the reverse current due to the transmission of the regenerative energy to the capacitor 26, the resonance phenomenon is utilized. Then, the regenerated reverse current flows by bypassing the primary winding 32 of the transformer 22, so that the capacitor 26 can be recharged smoothly, and the charging efficiency of the capacitor 26 is further improved. be able to.

  Next, some modifications of the discharge device 10 according to the above-described embodiment will be described with reference to FIGS.

  First, as shown in FIG. 6, the discharge device 10 a according to the first modification has substantially the same configuration as that of the discharge device 10 according to the present embodiment described above, but is connected in series with the semiconductor switch 24. The difference is that three diodes 64 are connected. Specifically, the cathode terminal of the third diode 64 is connected to the anode terminal of the semiconductor switch 24, and the anode terminal of the third diode 64 is connected to one end 40 of the primary winding 32 (the cathode terminal of the first diode 42). I am doing so.

  This eliminates the need to turn off the semiconductor switch 24, thereby simplifying the configuration of the control circuit 48 that drives and controls the semiconductor switch 24. When an SI thyristor is used as the semiconductor switch 24, it is usually necessary to draw from the gate a current that is substantially the same as the current flowing between the anode and the cathode in order to realize turn-off with the SI thyristor. This is an indispensable condition for forming a depletion layer near the gate, and therefore a gate circuit capable of controlling a large current is required. Furthermore, in order to realize high di / dt at the time of current interruption, it is necessary to interrupt a large current without connecting a snubber circuit, which may be disadvantageous in terms of reliability. In the first modified example, even if an SI thyristor is used as the semiconductor switch 24, it is not necessary to turn off the SI thyristor. In addition, it is advantageous for cost reduction.

  Next, as shown in FIG. 7, the discharge device 10 b according to the second modification has substantially the same configuration as that of the discharge device 10 according to the present embodiment described above, but in parallel with the capacitor 26, The difference is that four diodes 66 are connected. Specifically, the cathode terminal of the fourth diode 66 is connected to the + terminal of the capacitor 26, and the anode terminal of the fourth diode 66 is connected to the − terminal of the capacitor 26.

  Thereby, the residual charge of the capacitor 26 can be consumed by the fourth diode 66. Although not shown, a resistor may be connected in series with the fourth diode 66 in order to efficiently consume the residual charge.

  Next, as shown in FIG. 8, the discharge device 10 c according to the third modified example has substantially the same configuration as the discharge device 10 according to the present embodiment described above, but on the secondary side of the transformer 22, The difference is that a reset circuit 68 for resetting the saturation state of the transformer 22 is provided. Specifically, the reset circuit 68 includes a reset winding 70 wound so as to have a positive polarity with respect to the primary side of the transformer 22 separately from the secondary winding 34, and the reset winding 70. A DC power source 72, a resistor 74, and a reactor 76 connected in series.

  When the current Icd flows through the primary winding 32 in the first mode M1, the output current Io flows through the secondary winding 34, the current also flows through the reset circuit 68, and the induction energy is accumulated in the reactor 76. .

  Even when the transformer 22 is saturated (second mode M2), even if the output current Io flows steeply through the secondary winding 34 and a pulse voltage is applied to the reset circuit 68, it is blocked by the energy accumulated in the reactor 76. be able to.

  Thereafter, when the second mode M2 is finished and the output current Io becomes almost zero, the energy stored in the reactor 76 is released, and the current flows through the reset winding 70, whereby the transformer 22 Will be reset.

  Therefore, the cycle of first discharge (forward discharge in the first mode) → second discharge (reverse discharge in the second mode) can be repeated, and deodorization, sterilization, decomposition of harmful gases, purification, etc. This can be done efficiently.

  In addition, the discharge device according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

It is a circuit diagram which shows the structure of the discharge device which concerns on this Embodiment with the flow path of the electric current in 1st mode. In the discharge device according to the present embodiment, a diagram showing waveforms of a voltage Vo applied to the reactor, a voltage Vg applied to the reactor space, a voltage Vc applied to the dielectric of the reactor, and a current Io flowing through the reactor. is there. In the discharge device according to the present embodiment, it is a diagram showing the waveforms of the voltage Vcd across the capacitor, the current Icd flowing through the capacitor, the current Is flowing through the semiconductor switch, and the current Id1 flowing through the first diode. It is explanatory drawing which shows the distribution route of the electric current in the 2nd mode in the discharge device concerning this Embodiment. It is explanatory drawing which shows the motion of the electric current by the primary side of the trans | transformer in the discharge device concerning this Embodiment. It is a circuit diagram which shows the structure of the principal part of the discharge device which concerns on a 1st modification. It is a circuit diagram which shows the structure of the principal part of the discharge device which concerns on a 2nd modification. It is a circuit diagram which shows the structure of the discharge device which concerns on a 3rd modification. It is a circuit diagram which shows the structure of the high voltage pulse generation circuit which concerns on a prior art example. It is a perspective view which shows the structure of the general reactor used by silent discharge. It is a longitudinal cross-sectional view which shows the structure of the general reactor used by silent discharge. It is a figure which shows the equivalent circuit of the reactor connected between the output terminals of a high voltage pulse generation circuit. In the conventional high voltage pulse generation circuit, the voltage Vo applied to the reactor, the voltage Vg applied to the reactor space, the voltage Vc applied to the dielectric of the reactor, the current Io flowing through the reactor, the reactor space It is a figure which shows the waveform of the electric current Ig which flows.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a-10c ... Discharge device 12 ... High voltage pulse generation circuit 14 ... Reactor 16 ... DC power supply part 22 ... Transformer 24 ... Semiconductor switch 26 ... Capacitor 32 ... Primary winding 34 ... Secondary winding 42 ... First diode 44 ... Second diode 48 ... Control circuit 64 ... Third diode 66 ... Fourth diode 68 ... Reset circuit

Claims (7)

A saturable transformer and at least one semiconductor switch connected in series to both ends of the power supply unit;
A reactor connected to the secondary side of the transformer,
The reactor has a pair of electrodes, two dielectrics interposed between the pair of electrodes, and a space interposed between the two dielectrics,
A first discharge in the space of the reactor by a one-way current flowing on the secondary side of the transformer as the semiconductor switch is turned on;
A discharge device characterized by generating a second discharge in the space of the reactor by a reverse current flowing in the secondary side of the transformer as the transformer is saturated. The discharge device according to claim 1 , wherein
The power supply unit includes a capacitor to which a power supply voltage is supplied,
The discharge of the capacitor is performed by the one direction of the current flowing through the primary side of the transformer due to the turn-on of the semiconductor switches,
Discharge apparatus characterized by recharge to the capacitor by the reverse current flowing through the primary side of the transformer due to the transmission of the regenerative energy due to the resonance of the primary side of the transformer after the transformer saturation is performed. The discharge device according to claim 2 , wherein
The parallel to the semiconductor switch, and the discharge apparatus characterized by being connected diode in the forward direction with respect to the reverse current due to transfer to the condenser of the regenerative energy. The discharge device according to claim 3 , wherein
The parallel to the primary winding of the transformer, and a discharge device, wherein a second diode connected in the forward direction with respect to the reverse current due to transfer to the condenser of the regenerative energy. The discharge device according to claim 3 or 4 ,
Wherein the semiconductor switch in series, and said after transformer saturation, the discharge device, wherein a third diode is connected in the forward direction with respect to the direction of the current flowing through the primary side of the transformer. In the discharge device according to any one of claims 2 to 5 ,
A discharge device, wherein a fourth diode is connected in parallel to the capacitor and in a forward direction with respect to the current in one direction flowing on a primary side of the transformer . In the discharge device according to any one of claims 1 to 6 ,
A discharge device comprising a reset circuit for resetting the saturation of the saturated transformer on a secondary side of the transformer.

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