JPH10108480A - Pulse-type ac high-voltage power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rising and falling characteristics of a positive/negative pulse high-voltage and obtain high-speed pulse high voltage and also improve dielectric strength of an internal circuit with respect to a high voltage. SOLUTION: A first set of switching section SW1, a second set of switching section SW2, and a third set of switching section SW1 and the second set of switching section SW2 is connected to a load R, and a fourth set of switching section SW4 is connected between a negative voltage generating section and the load R. Corresponding to four sets of switching sections, four sets of coil strings L1/L2/L3/L4 formed of n-troidal coils TC-1 to TC-n are provided, and four sets of FET are turned on and off in the predetermined sequence by simultaneously applying a pulse current to the wirings of n-troidal coils TC-1 to TC-n for each set with the control lines CL1/CL2/CL3/CL4, provided through the n-troidal coils TC-1 to TC-n.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse type AC high voltage power supply for applying a positive and negative pulse high voltage to a discharge electrode or the like, and relates to a plasma generator, a corona discharge treatment device, an ion generator, a static eliminator, a sputtering device and the like. It can be used widely as a power source for devices, laser generators, ozone generators and the like.

[0002]

2. Description of the Related Art Heretofore, in a corona discharge device, a plasma generator, or the like for performing a high-voltage discharge, as a method of applying a positive or negative AC high voltage to a discharge electrode, a voltage is generally boosted by using a high-voltage transformer. However, in order to increase the voltage, it is necessary to increase the number of turns of the secondary winding of the transformer, and the stray capacitance on the secondary side increases in proportion to the number of turns. Therefore, as shown in FIG. When a pulse signal is input to the primary side of the output voltage, the rising and falling waveforms of the output voltage do not become the same as the input signal waveform, as shown in FIG. There was a disadvantage that it was delayed.

Further, when the capacitance C of the load is large due to the large number of secondary windings, the voltage waveform between both ends of the load is affected by the capacitance C as shown in FIG. And (B)
(D) that the rising and falling becomes worse than the waveforms of the waveforms, and that the charging / discharging current generated at the time of rising and falling becomes smaller as shown in FIG. There is a drawback that a resonance phenomenon occurs at a certain frequency due to the coupling between the inductance L and the capacitance C.

[0004] As another conventional method, a high voltage DC power supply and a rotating plate provided with a spark gap are used, and a high DC voltage is applied to the rotating plate to forcibly spark between the spark gaps. There is a method of obtaining a pulse signal. However, this method has disadvantages such as inability to increase the speed and a short mechanical life.

[0005]

The problem to be solved by the present invention is as follows.
To improve the rising and falling characteristics of the positive and negative pulse high voltages applied to the discharge electrodes, etc., second, to increase the speed of operation, and third, to generate positive and negative pulse high voltages. Fourth, it is necessary to ensure a sufficient withstand voltage of the internal circuit. Fourth, it is possible to easily adjust the generation cycle of the positive and negative pulse high voltage. The purpose of the present invention is to adjust the voltage of one polarity so that the other polarity is not affected.

[0006]

According to a first aspect of the present invention, a pulse type AC high voltage power supply for achieving the first, second, and third objects, a positive voltage generating section for generating a positive DC high voltage, and a negative voltage generating section for generating a negative DC high voltage. And a first, second, third, and fourth four sets of switching units each of which is formed by serially coupling a plurality of semiconductor switching elements, And a drive circuit for turning on / off the semiconductor switching elements of the switching unit by a pulse signal for each set. A first set of switching units, a second set of switching units, and a third set of switching units are connected in series between the positive voltage generation unit and the ground, and the first set of switching units and the second set of switching units are connected. A connection point with the switching unit is connected to the load, and when the first set of switching units is turned on, a positive voltage of the positive voltage generation unit is applied to the load, and a positive voltage is applied between the negative voltage generation unit and the load. Four switching units are connected so that when the fourth set of switching units is turned on, the negative voltage of the negative voltage generation unit is applied to the load. The drive circuit turns on the semiconductor switching element by a pulse signal flowing through the winding of each toroidal coil. The drive circuit has four sets of the toroidal coils corresponding to the four sets of the switching units, respectively. After the semiconductor switching elements of the first and second sections are simultaneously turned on and a positive voltage is applied to the load, the positive charges charged to the load are connected to the semiconductor switching elements of the second and third sets of switching sections or are connected in parallel to these. After the semiconductor switching elements of the fourth set of switching units are turned on and a negative voltage is applied to the load, the negative charge charged to the load is The semiconductor switching elements of the third and second sets of switching units or a diode connected in parallel to these, As it is discharged by the circuit leading to the load through the de periodically a pulse current in a predetermined order the four sets of the toroidal coil control lines through respectively.

A pulse AC high-voltage power supply according to a second aspect of the present invention, which also achieves the first, second, and third objects, comprises a positive voltage generator for generating a positive DC high voltage, and a negative DC high voltage. A first, second, third, and fourth pairs of a negative voltage generator that generates a plurality of semiconductor switching elements connected in series.
And a drive circuit for turning on / off the semiconductor switching elements of each set of switching units by a pulse signal for each set. A first set of switching units, a second set of switching units, and a third set of switching units are connected in series between the positive voltage generation unit and the ground, and the first set of switching units and the second set of switching units are connected. A connection point with the switching unit is connected to a load, and when the first set of switching units is turned on, a positive voltage of the positive voltage generation unit is applied to the load. A fourth switching unit is connected between a connection point with the switching unit, the negative voltage generating unit, and the load, and the negative voltage of the negative voltage generating unit is turned on when the second and fourth sets of switching units are turned on. Is the connection relationship applied to the load. The drive circuit turns on the semiconductor switching element by a pulse signal flowing through the winding of each toroidal coil. The drive circuit has four sets of the toroidal coils corresponding to the four sets of the switching units, respectively. After the semiconductor switching elements are turned on at the same time and a positive voltage is applied to the load, the positive charge charged to the load is changed to the second set,
Discharged by the semiconductor switching elements of the third set of switching units or a circuit connected to the ground via diodes connected in parallel to these, and then the semiconductor switching elements of the second and fourth sets of switching units are turned on. After the negative voltage is applied to the load, the negative charge charged to the load reaches the load from the ground through the semiconductor switching elements of the third and second sets of switching units or the diodes connected in parallel to these. A pulse current is periodically applied in a predetermined order to a control line passing through each of the four toroidal coils so as to be discharged by the circuit.

In order to attain the fourth object, a drive circuit comprises a frequency-adjustable oscillation circuit for generating a pulse signal, and a pulse signal which is supplied to a control line of four sets of toroidal coils in a predetermined order. And a sequential circuit for supplying a pulse current. Further, the drive circuit includes first and second oscillating circuits capable of adjusting a frequency for generating a pulse signal, a first state capable of outputting only the pulse signal from the first oscillating circuit to the sequential circuit, A modulation circuit capable of switching to a second state in which a pulse signal obtained by ANDing and modulating pulse signals from both of the second oscillation circuits and outputting the pulse signal to a sequential circuit is provided. When such a modulation circuit is provided, a pulse signal for turning on / off the four switching units can be modulated with a pulse having a longer time width to perform an intermittent operation.

In order to achieve the fifth object, a switching unit is connected to a load without using a transformer.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an equivalent circuit of a high-voltage switching circuit according to a first embodiment of the present invention. In this equivalent circuit, a positive DC power supply + E is a positive voltage generator for generating a positive voltage, and a negative DC power supply -E is a negative voltage generator for generating a negative voltage, and four switches. SW1
SW2, SW3, and SW4 each include a first, second, third, and fourth switching units each of which is formed by connecting a plurality of semiconductor switching elements (specifically, FETs, IGBTs, and the like) in series. Shown, each with a diode D1
D2, D3 and D4 are connected in parallel. The load R is
It represents a discharge electrode or the like for applying a positive or negative high voltage, one end of which is grounded. The first switch SW1, the second switch SW2, and the third switch SW3 are connected in series between the positive DC power supply + E and the ground. Also,
The fourth switch SW4 is connected between the negative DC power source -E and the load R, and a connection point between the first switching SW1 and the second switch SW2 is also connected to the load R.

FIGS. 2 to 5 show the switching state of the on / off operation of the four switches SW1, SW2, SW3 and SW4 (four switching elements) of the first embodiment, FIG.
FIG. 7 shows the on / off relationship, and FIG. 7 shows a timing chart. An operation example of the first embodiment will be described with reference to these drawings.

The four switches SW1, SW2, SW3,
When the first switch SW1 is turned on (in FIG. 6) as shown in FIGS. 2 and 7 from the state in which all of the switches SW4 are turned off as shown in FIG. 1 (in FIG. 6), the positive DC power supply + E From the first switch SW turned on
1 and the current flowing toward the ground (in the direction of I1) through the load R, a positive pulse voltage having a good rise proportional to the positive power supply voltage + E is applied to the load R without being boosted by the transformer, and the load R Is charged to a positive polarity.

Next, after a predetermined time, the first switch SW1 is turned off as shown in FIGS. 3 and 7, and immediately after that, the second switch SW2 is turned on instantly (in FIG. 6). A third diode D3 connected in parallel to the second switch SW2 that has been turned on and the third switch SW3 that has been turned off,
Is discharged (in the direction of I2) by the flow to the ground through the gate electrode, so that a positive pulse voltage having a good fall with respect to the load R is obtained.

After a predetermined time, the second switch SW2 is turned off as shown in FIG. 4 and FIG.
Is turned on (in FIG. 6),
This time, the fourth switch SW4 turned on from the load R
To DC power source -E of negative polarity through (direction of I3)
Since a current flows, a negative pulse voltage with a good fall proportional to the negative power supply voltage -E is applied to the load R without being boosted by the transformer, and the load R is charged to the negative polarity.

Then, after a predetermined time, the fourth switch SW4 is turned off as shown in FIGS. 5 and 7, and immediately thereafter, the third switch SW3 is turned on instantly (in FIG. 6). Is charged from the load R to the ground again via the second diode D2 connected in parallel with the third switch SW3 turned on from the ground and the second switch SW2 turned off from the ground. Since the discharge is caused by the flow (in the direction of I4), a negative pulse voltage with a good rise with respect to the load R is obtained at this time.

By repeating such an operation, positive and negative pulse voltages having good rising and falling characteristics are periodically applied to the load R as shown in the lowermost stage of FIG. The advantage of this circuit is that even if the impedance of the load R is very high, the positive charge charged in the load R is transferred to the second switch SW2 and the third diode D3, and the negative charge is transferred to the third switch SW3. And the second diode D2, and the load R can be charged at a high speed by the first switch SW1 or the fourth switch SW4 even when a positive or negative voltage is applied. A fast positive and negative pulse voltage can be obtained.

Next, the circuit configuration is the same as that of the first embodiment shown in FIG. 1, except that four switches SW1, SW2 and SW3 are provided.
Another operation example in which the ON / OFF operation timing of SW4 is changed from the above operation example will be described. 8 to 12 show four switches SW1, SW2, SW3, and SW4.
FIG. 13 shows the on / off operation switching state.
FIG. 14 shows a timing chart of the off relationship.

First, as shown in FIG.
In a state where W1 is turned off, the second and third switches SW2 and SW3 are turned on, and the fourth switch SW4 is turned off (in FIG. 13), both ends of the load R are connected to the ground. No voltage is applied.
From this state, as shown in FIGS. 9 and 14, when the first switch SW1 is turned on immediately after the second switch SW2 is turned off (in FIG. 13), the positive DC power supply + E is turned on. The current flowing toward the ground (in the direction of I1) flows through the first switch SW1 and the load R, and a positive pulse voltage having a good rise proportional to the positive power supply voltage + E is applied to the load R. To be charged.

Next, as shown in FIGS. 10 and 14,
When the second switch SW2 is turned on immediately after the first switch SW1 is turned off (in FIG. 13), the load R
Is discharged by the flow to the ground (in the direction of I2) via the second switch SW2 which is turned on and the third switch SW3 which is continuously turned on. A positive pulse voltage having a good fall with respect to R is obtained.

As shown in FIGS. 11 and 14, when the fourth switch SW4 is turned on immediately after the third switch SW2 is turned off (in FIG. 13), this time,
Since a current flows from the load R to the negative DC power supply -E (in the direction of I3) through the fourth switch SW4 which is turned on, a negative pulse voltage with a good fall proportional to the negative power supply voltage -E Is applied to the load R, and the load R is charged to a negative polarity.

Next, as shown in FIG. 12 and FIG.
When the third switch SW3 is turned on immediately after the fourth switch SW4 is turned off (in FIG. 13), the load R
Is charged by the flow from the load R to the ground again via the third switch SW3 turned on from the ground and the second switch SW2 continuously turned on from the ground (in the direction of I4). ) Since the discharge is performed, a negative pulse voltage with a good rise with respect to the load R is obtained at this time.

Next, FIG. 15 shows an equivalent circuit of the high-voltage switching circuit according to the second embodiment. In this case, the first switch SW1, the second switch SW2, and the third switch SW3 are connected to the positive DC power supply + as in the above-described example.
E and ground, the load R is connected to the connection point between the first switch SW1 and the second switch SW2.
Is connected, and between the connection point between the second switch SW2 and the third switch SW3 and the negative DC power source -E,
The fourth switch SW4 is connected.

An operation example of the second embodiment will be described. FIGS. 15 to 19 show four switches S in this case.
The switching state of the ON / OFF operation of W1, SW2, SW3, and SW4 is shown. However, the on / off relationship is the same as in FIG. 13, and the timing chart is the same as in FIG.

First, as shown in FIG. 15, the first switch SW1 is turned off, and the second and third switches SW2 and SW3 are turned off.
Are turned on and the fourth switch SW4 is turned off (in FIG. 13), both ends of the load R are connected to the ground, so that no positive or negative voltage is applied to the load R.
From this state, as shown in FIGS. 16 and 14, immediately after the second switch SW2 is turned off, the first switch SW1 is turned off.
Is turned on (in FIG. 13), a current flows from the positive DC power supply + E to the ground (in the direction of I1) through the first switch SW1 and the load R that are turned on, and the positive power supply voltage A positive pulse voltage with a good rise proportional to + E is applied to the load R, and the load R is charged to a positive polarity.

Next, as shown in FIGS. 17 and 14,
When the second switch SW2 is turned on immediately after the first switch SW1 is turned off (in FIG. 13), the load R
Is discharged by the flow to the ground (in the direction of I2) via the second switch SW2 which is turned on and the third switch SW3 which is continuously turned on. A positive pulse voltage having a good fall with respect to R is obtained.

As shown in FIGS. 18 and 14, when the fourth switch SW4 is turned on immediately after the third switch SW2 is turned off (in FIG. 13), this time,
Since a current flows from the load R to the negative DC power supply -E (in the direction of I3) through the second switch SW2 and the fourth switch SW4 that are continuously turned on, the negative power supply voltage is applied. A negative pulse voltage with a good fall proportional to -E is applied to the load R, and the load R is charged to a negative polarity.

Next, as shown in FIGS. 19 and 14,
When the third switch SW3 is turned on immediately after the fourth switch SW4 is turned off (in FIG. 13), the load R
Is charged by the flow from the load R to the ground again via the third switch SW3 turned on from the ground and the second switch SW2 continuously turned on from the ground (in the direction of I4). ) Since the discharge is performed, a negative pulse voltage with a good rise with respect to the load R is obtained at this time.

Next, the circuit configuration is the same as that of the second embodiment shown in FIG. 15, but the four switches SW1, SW2, SW
3. Another operation example in which the ON / OFF operation timing of SW4 is changed from the above operation example will be described. FIG. 20 to FIG. 24 show four switches SW1, SW2, SW3, and SW.
FIG. 25 shows a switching state of the on / off operation of No. 4, FIG. 25 shows its on / off relationship, and FIG. 26 shows a timing chart.

The four switches SW1, SW2, SW3,
SW4 is turned off as shown in FIG.
5), when the first switch SW1 is turned on as shown in FIGS. 21 and 26 (in FIG. 25), the first switch SW1 and the load R which are turned on are switched from the positive DC power supply + E. Head to the ground (I1
Since the current flows, a positive pulse voltage with a good rise proportional to the positive power supply voltage + E is applied to the load R, and the load R is charged to the positive polarity.

Next, after a predetermined time, the first switch SW1 is turned off as shown in FIGS. 22 and 26, and immediately after that, the second switch SW2 is turned on (in FIG. 25). Positive charges correspond to the second switch SW2 turned on and the third switch SW2 turned off.
Is discharged (in the direction of I2) by the flow to the ground via the third diode D3 connected in parallel to the switch SW3 of the switch SW3.

As shown in FIGS. 23 and 26, the second
With the switch SW2 of the fourth switch ON, the fourth switch S
When W4 is turned on (in FIG. 25), the load R goes to the negative DC power source -E through the second switch SW2 and the fourth switch SW4 that are turned on (I3). Direction) current flows,
A negative pulse voltage with a good fall proportional to the negative power supply voltage -E is applied to the load R, and the load R is charged to the negative polarity.

Next, after a predetermined time, as shown in FIGS. 24 and 26, the second and fourth switches SW2 and SW4 are turned off, and then the third switch SW3 is turned on instantaneously (see FIG. 25). ), The negative charge charged on the load R side is further connected to the third switch SW3 turned on from the ground and the second switch SW2 turned off via the second diode D2 connected in parallel to the load R. , And is discharged again (in the direction of I4) from the flow to the ground.

FIG. 27 shows a high-voltage switching circuit 1 shown as an equivalent circuit as described above and a low-voltage side circuit for turning on / off the semiconductor switching elements of the four switching units SW1, SW2, SW3, and SW4 for each group. A specific example of a part of the drive circuit, that is, the switching control circuit 2 is shown. As shown in FIG.
Each of SW2, SW2, and SW4 is a device in which n FETs (field effect transistors) 3-1 to 3-n are connected in series to increase the withstand voltage against a high voltage. n are connected in parallel. It should be noted that the high-voltage switching circuit 1 shown in the figure corresponds to the equivalent circuit shown in FIG.

The switching control circuit 2 corresponds to each of the four switching units SW1, SW2, SW3, and SW4, and has n toroidal coils TC-1 to TC-1.
Four sets of coil arrays L1, L2, L3, L composed of TC-n
4 Each set of n toroidal coils TC-1 to TC-1
Control lines (high-withstand voltage lines) CL1, CL2, CL3, and CL4 are passed through the ring-shaped core of TC-n for each set. In this case, the control lines CL1, CL2, CL3, CL4
In order to insulate the high-voltage side (high-voltage switching circuit 1) and the low-voltage side (switching control circuit 2) from contacting the core. Each control line CL1, CL2, CL3
・ CL4 has a control transistor (FET) T1 ・ T
2, T3 and T4 are connected respectively.

The n toroidal coils TC-1 to TC-
Amplifier circuits G-1 to G-n are respectively connected to the n windings, and the output terminals of these amplifier circuits are connected to the corresponding ones of the switching units SW1, SW2, SW3, and SW4 of the corresponding set.
Are connected to the gates of the FETs 3-1 to 3-n, respectively.

Therefore, for example, when the transistor T1 of the first set of coil rows L1 is turned on by a pulse signal and a pulse current is applied to the first set of control lines CL1, the first set of n toroidal coils TC-1 To TC-n at the same time, a pulse current flows through the windings of the first set of switching units SW1.
The FETs 3-1 to 3-n are simultaneously turned on. The same applies to other sets, and by adopting such a switching control method, n sets of FETs themselves and four sets of switching units SW1, SW2, and SW each connected in series are provided.
3. SW4 switching can be performed at high speed.

As described above, each of the switching units SW1
SW2, SW3, and SW4 are all FETs that are semiconductor switching elements, and n FETs are connected in series to increase the withstand voltage against a high voltage.
The switching operation is performed at a higher speed, and the four sets of switching units are operated as shown in the above-described equivalent circuit for both positive and negative voltages, so that a rising and falling waveform proportional to the input signal has a steep waveform. Positive and negative high voltages are obtained alternately and can be directly applied to the load R without being boosted by a transformer. Therefore, even if the capacitance of the load R is large, the charging / discharging current generated at the time of rising / falling of the positive / negative high voltage can be very large as shown in FIG.

The switching circuit 1 and the load R are
As shown in FIG. 27, if connection is made via a resistor or an inductance 4 without using a transformer, the time constant at the time of charging / discharging can be adjusted by the resistance or the inductance, and the required current according to the load R can be selected.

When a transformer 5 is used as shown in FIG. 33 to boost the voltage, and this transformer 5 is capacitively coupled by a capacitor 6 as a direct load R to the switching circuit 1, a positive voltage applied to the switching circuit 1 When the input voltage and the negative input voltage are respectively varied, FIG.
As shown in (5), since a signal whose positive and negative are averaged is input to the transformer 5, the positive or negative output waveform affects the output waveform of the other polarity even if one of the positive or negative input voltage is adjusted. Would. For this reason, even if an attempt is made to achieve an ion balance for generating equal amounts of positive and negative ions due to discharge, it is very difficult to adjust the ion balance.

On the other hand, according to the present invention, a positive input voltage (high voltage) and a negative input voltage (high voltage) applied to the switching circuit 1 are directly used without using a transformer. Therefore, even if the positive or negative input voltage is adjusted, it does not affect the output waveform of the other polarity, and the ion balance can be easily adjusted.
In addition, it is possible to easily output only one of the positive and negative pulse high voltages.

FIG. 28 shows the overall configuration of a pulse AC high voltage power supply according to the present invention. In the figure, AC 200 V or AC 100 V from a commercial AC power supply is supplied to a positive voltage generator 8 and a negative voltage generator 9 via a sequence circuit 7, and is adjusted by a positive voltage regulator 10 from the positive voltage generator 8. The generated positive DC high voltage and the negative DC high voltage adjusted by the negative voltage regulator 11 are respectively generated from the negative voltage generator 9 and are simultaneously applied to the high voltage switching circuit 1 having the above-described configuration. The AC voltage that has passed through the sequence circuit 7 is also applied to a constant voltage power supply 12 for a logic circuit that generates a constant low DC voltage (for example, 24 V).

As a pulse generation source for the switching control circuit 2, a first oscillation circuit 13 and a second oscillation circuit 14 having different frequencies are provided. First oscillation circuit 1
3 is higher than the frequency of the second oscillation circuit 14,
The first oscillation circuit 13 can be varied within a range of several KHz to several tens KHz based on the reference frequency by a first frequency adjuster 15, and the second oscillation circuit 14 can be adjusted by a second frequency adjuster 16. Several hundred Hz to several KH based on frequency
It can be varied in the range of z.

The pulse signals from the first and second oscillating circuits 13 and 14 are applied to a sequential circuit 18 via a modulating circuit 17, and the sequential circuit 18 generates a pulse signal as shown in FIG. After being generated into four pulses in the order, four sets of coil arrays L1 and L
2, L3, L4 transistors T1, T2, T3, T4
Is input to

The modulation circuit 17 includes a modulation switch 19, first, second, and third AND circuits 20, 21, and 22, an inverter circuit 23, and an OR circuit 24. The sequential circuit 18 delays the output of the first, second, third, and fourth one-shot circuits 25, 26, 27, and 28 and the first one-shot circuit 25 to form the second one-shot circuit 26. The first delay circuit 29 to be input, the second delay circuit 30 to delay the output of the second one-shot circuit 26 and input to the third one-shot circuit 27, and the output of the third one-shot circuit 27 And a third delay circuit 31 for inputting the delayed signal to the fourth one-shot circuit 28.

The operation of the circuit configuration shown in FIG. 28 will be described with reference to the timing charts of FIGS. 29 and 30. When the modulation switch 19 is turned on, the inverter circuit 23
Becomes H (high level), and the first AND circuit 2
Input to one of 0. Since the other input of the AND circuit 20 is a pulse from the first oscillation circuit 13 (the uppermost stage in FIG. 30), this pulse is sequentially passed through the OR circuit 24 as shown in the uppermost stage in FIG. The signal is input to the first one-shot circuit 18 of the circuit 18, and at the rise thereof, the first one-shot circuit 18 is activated to output a pulse having a predetermined width. And second, third, and fourth one-shot circuits 2
6. 27. 28 operate sequentially with a slight delay, and output pulses of a predetermined width. The output pulses of these four one-shot circuits 25, 26, 27, 28 are input to the transistors T1, T2, T3, T4 of the four sets of coil arrays L1, L2, L3, L4 shown in FIG. , The high-voltage switching circuit 1 operates as described above.

On the other hand, when the modulation switch 19 is turned off, one of the second AND circuits 21 becomes H, and the other input of the AND circuit 21 is a pulse from the second oscillation circuit 14. 30 is output from the AND circuit 21 as it is as shown in the second stage in FIG. 30, and the third signal is output together with the pulse from the first oscillation circuit 13 (the uppermost stage in FIG. 30).
Of the AND circuit 22, and from the AND circuit 22,
The modulated pulse is output intermittently (oscillation cycle of the second oscillation circuit 14) as a modulation pulse as shown in the third stage of FIG. This modulated pulse passes through the OR circuit 24 as described above, and
, The high-voltage switching circuit 1 operates intermittently at the timing shown at the bottom of FIG.

The one-shot circuits 25, 26, 27
The reason why the delay circuits 29, 30 and 31 are provided between each of the two switching units SW1 and SW2 is that if there is no slight delay for the next pulse output operation after the one-shot operation is completed, When the SW3 and SW4 are switched, they may be turned on at the same time.

The positive voltage generator 8 and the negative voltage generator 9
Are separately adjusted in order to achieve ion balance by controlling the output from the high-voltage switching circuit 1 to be asymmetrical with respect to 0 V as a reference.

[0050]

As described above, according to the present invention, the following effects can be obtained. According to the first, second and third aspects of the present invention, since the residual charge of the load can be positively discharged for each of the positive and negative sides, the rising and falling characteristics of the pulse high voltage can be improved, and Since the operation can be speeded up, for example, when used as a power source of a static eliminator, the static elimination efficiency can be improved by increasing the amount of generated ions. In addition, the four sets of switching units increase the withstand voltage against high voltage by connecting a plurality of semiconductor switching elements in series, and turn on each set of semiconductor switching elements by a pulse signal flowing through the winding of each toroidal coil, Moreover, since the toroidal coils of each group are simultaneously controlled by the control line for each group, even if a plurality of semiconductor switching elements are connected in series, the on / off operation can be easily and quickly performed. Further, by penetrating the control line through the toroidal coil, the high voltage side and the low voltage side can be insulated, so that the safety of the internal circuit can be sufficiently ensured.

According to the fourth aspect of the present invention, the pulse signals for turning on and off the four switching units can be intermittently operated by modulating them with pulses having a longer time width. Can be easily adjusted.

According to the fifth aspect of the present invention, since the switching unit is connected to the load without passing through the transformer,
Adjusting the voltage of one of the positive polarity and the negative polarity does not affect the other polarity.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a first embodiment of a high-voltage switching circuit according to the present invention.

FIG. 2 is a circuit diagram showing a state in which a positive voltage is applied to a load in the above power supply.

FIG. 3 is a circuit diagram showing a state in which discharge is performed after the state in FIG. 2;

FIG. 4 is a circuit diagram showing a state where a negative voltage is applied to a load after the state of FIG. 3;

FIG. 5 is a circuit diagram showing a state where discharge is performed after the state of FIG. 4;

FIG. 6 shows ON / OFF of four switches in FIGS. 1 to 5;
It is a relation diagram of OFF switching.

FIG. 7 is also a timing chart.

FIG. 8 is a circuit diagram showing another operation example different from the above with the same circuit configuration as that of FIG. 1;

FIG. 9 is a circuit diagram showing a state in which a positive voltage is applied to a load in the above power supply;

FIG. 10 is a circuit diagram showing a state where discharge is performed after the state of FIG. 9;

11 is a circuit diagram showing a state where a negative voltage is applied to a load after the state of FIG. 10;

FIG. 12 is a circuit diagram showing a state in which discharge is performed after the state in FIG. 11;

FIG. 13 is a relationship diagram of on / off switching of four switches in FIGS. 8 to 12;

FIG. 14 is also a timing chart.

FIG. 15 is an equivalent circuit diagram of the first embodiment of the high-voltage switching circuit.

FIG. 16 is a circuit diagram showing a state in which a positive voltage is applied to a load in the above power supply;

FIG. 17 is a circuit diagram showing a state of being discharged after the state of FIG. 16;

FIG. 18 is a circuit diagram showing a state where a negative voltage is applied to the load after the state of FIG. 17;

FIG. 19 is a circuit diagram showing a state of being discharged after the state of FIG. 18;

FIG. 20 is a circuit diagram showing another example of the operation having the same circuit configuration as that of FIG. 15;

FIG. 21 is a circuit diagram showing a state where a positive voltage is applied to a load in the above power supply;

FIG. 22 is a circuit diagram showing a state where discharge is performed after the state of FIG. 21;

FIG. 23 is a circuit diagram showing a state where a negative voltage is applied to the load after the state of FIG. 22;

FIG. 24 is a circuit diagram showing a state of being discharged after the state of FIG. 23;

FIG. 25 is a relationship diagram of on / off switching of four switches in FIGS. 20 to 24;

FIG. 26 is also a timing chart.

FIG. 27 shows a high-voltage switching circuit shown by an equivalent circuit;
FIG. 4 is a circuit diagram showing a specific example of a switching control circuit that turns on and off the semiconductor switching elements of the four switching units for each group.

FIG. 28 is a block diagram showing an overall configuration of a pulse AC high-voltage power supply according to the present invention.

FIG. 29 is a timing chart showing the normal operation of the above.

FIG. 30 is a timing chart showing an operation at the time of modulation.

FIG. 31 is a timing chart showing a signal deformation process in a conventional example in which voltage is boosted using a high-voltage transformer.

FIG. 32 is a timing chart of an output voltage waveform and a load current waveform according to the present invention.

FIG. 33 is a circuit diagram showing a reference example in which a transformer is used to boost the voltage, and this transformer is capacitively coupled by a capacitor as a direct load to a switching circuit.

FIG. 34 is a timing chart showing that, when the input voltage of one of the positive and negative polarities is changed, the output signal waveform of the other polarity is deformed.

[Explanation of symbols]

SW1, SW2, SW3, SW4 Four sets of switching units D1, D2, D3, D4 Diode R Load + E Positive DC power supply (positive voltage generation unit) -E Negative DC power supply (negative voltage generation unit) 1 High voltage switching Circuit 2 Switching control circuit 3-1 to 3-n FETs D-1 to D-n diodes L1, L2, L3, L4 Coil train TC-1 to TC-n Toroidal coil CL1, CL2, CL3, CL4 Control line 8 Positive Voltage generator 9 Negative voltage generator 13 First oscillating circuit 14 Second oscillating circuit 17 Modulation circuit 18 Sequential circuit

Claims (5)

[Claims] A first voltage generating section for generating a positive DC high voltage; a negative voltage generating section for generating a negative DC high voltage; A switching circuit for switching the semiconductor switching elements of each of the second, third and fourth switching units and a semiconductor switching element of each of these sets on and off with a pulse signal for each pair; Between the ground and the first
A first set of switching units, a second set of switching units, and a third set of switching units are connected in series, and a connection point between the first set of switching units and the second set of switching units is connected to a load. A positive voltage of the positive voltage generator is applied to the load when the switching units of the set are turned on, and a fourth switching unit is connected between the negative voltage generator and the load to form the fourth group. When the switching section is turned on, the negative voltage of the negative voltage generating section is applied to the load, and the drive circuit turns on the semiconductor switching element by a pulse signal flowing through the winding of each toroidal coil. There are four sets of the toroidal coils corresponding to the four sets of switching units, respectively, and the semiconductor switching elements of the first set of switching units are simultaneously turned on to apply a positive voltage to the load. After that, the positive charge charged to the load is discharged by a circuit that reaches the ground via the semiconductor switching elements of the second and third sets of switching units or diodes connected in parallel to these, and then, After the semiconductor switching elements of the fourth set of switching units are turned on and a negative voltage is applied to the load,
The negative charge charged to the load is transferred from ground to the third pair,
The control lines passing through the four sets of toroidal coils are periodically arranged in a predetermined order so as to be discharged by the semiconductor switching elements of the second set of switching units or a circuit that reaches the load via diodes connected in parallel to the semiconductor switching elements. A pulse-type AC high-voltage power supply characterized in that a pulse current is supplied to the power supply. A first voltage generating section for generating a positive DC high voltage; a negative voltage generating section for generating a negative DC high voltage; A switching circuit for switching the semiconductor switching elements of each of the second, third and fourth switching units and a semiconductor switching element of each of these sets on and off with a pulse signal for each pair; Between the ground and the first
A first set of switching units, a second set of switching units, and a third set of switching units are connected in series, and a connection point between the first set of switching units and the second set of switching units is connected to a load. When the switching units of the set are turned on, the positive voltage of the positive voltage generating unit is applied to the load, and
A fourth switching unit is connected between a connection point between the switching unit of the set and the switching unit of the third set, the negative voltage generating unit and the load, and the switching units of the second and fourth sets are turned on. When this happens, the negative voltage of the negative voltage generator is applied to the load, and the drive circuit turns on the semiconductor switching element by a pulse signal flowing through the winding of each toroidal coil. After four semiconductor switching elements of the first switching unit are simultaneously turned on and a positive voltage is applied to the load,
The positive charge charged to the load is discharged by the semiconductor switching elements of the second and third sets of switching units or a circuit that is connected to the ground via diodes connected in parallel to the semiconductor switching elements. After the semiconductor switching elements of the fourth set of switching units are turned on and a negative voltage is applied to the load, the negative charge charged to the load is transferred from the ground to the semiconductor switching of the third set and the second set of switching units. A pulse current is periodically supplied in a predetermined order to a control line passing through each of the four toroidal coils so as to be discharged by a circuit that reaches a load via the element or a diode connected in parallel to the element. Pulsed AC high voltage power supply. 3. A drive circuit, comprising: an oscillation circuit capable of adjusting a frequency for generating a pulse signal; and an order in which the pulse signal is input and a pulse current is periodically applied to control lines of four sets of toroidal coils in a predetermined order. The pulse AC high-voltage power supply according to claim 1 or 2, further comprising a circuit. 4. A drive circuit comprising a first and a second oscillation circuit capable of generating a pulse signal, the frequency of which is adjustable, and a first circuit capable of outputting only a pulse signal from the first oscillation circuit to a sequential circuit.
And a modulation circuit that can switch between a state in which the pulse signals from the first and second oscillation circuits are logically ANDed and a second state in which a pulse signal obtained by modulating the pulse signal is output to the sequential circuit. The pulsed AC high-voltage power supply according to claim 3, wherein 5. The pulse AC high-voltage power supply according to claim 1, wherein the switching unit is connected to a load without passing through a transformer.