JPH0638714B2 - High voltage ultra short pulse power supply - Google Patents

Description

TECHNICAL FIELD The present invention is intended for loads requiring a pulse high voltage having a remarkably short pulse width, including pulse charging of an electrostatic precipitator and pulse charging of a boxer charger. The present invention relates to a power supply device for continuously generating a high voltage ultrashort pulse having a pulse width of (ns).

2. Description of the Related Art The circuit shown in FIG. 1 is a circuit for generating a pulse having a short width, which is generally used in the past, and its operation will be described below.

The AC voltage supplied from the AC power supply 1 is boosted to a high voltage by the step-up transformer 2 and then single-phase full-wave rectified by the rectifiers 3 to 6, and the capacitor 8 is charged through the current limiting resistor 7. The voltage of the capacitor 8 rises as it is charged, and when it reaches the spark generation voltage Vs of the spark gap 9 that constitutes the spark switch, a spark is generated here, and the capacitor is passed between the output terminals 10 and 11 to which the load can be connected. Is discharged and a high voltage pulse is generated between terminals 10 and 11. The biggest problem when sparks occur in the spark gap is the continuous sparks or the continuous current of the discharge current. To eliminate these, the time constant for charging the capacitor 8 must be increased. The resistor 7 requires a considerably large resistance value. This time constant needs to be about 2 mSec in order to eliminate the follow-up of the spark discharge, and as a result, the number of pulses generated in a half cycle of the AC power supply is practically limited to about 3 times. Although the self-destruction type spark gap is inexpensive, there is a drawback in that the spark voltage Vs varies depending on the temperature, atmospheric pressure, the state of the gap surface, etc., and the pulse generation circuit and the interval are not constant. As the spark gap, a so-called three-point spark gap with a trigger electrode, a laser trigger spark gap in which sparks are triggered by a laser beam, or a gap enclosed in pressurized SF ₆ gas to increase the switch speed Alternatively, a container in which a spark switch is enclosed in a container containing hydrogen gas can be used. When the trigger type spark gap is used, the spark generation voltage and the spark generation interval become constant, but there is a drawback that it becomes expensive.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional spark gap, it is necessary to suppress the rising speed of the capacitor charging voltage in order to prevent the continuous spark discharge. For this reason, the voltage loss in the current limiting resistor 7 inserted in series is extremely large, which is the greatest drawback. Moreover, since the charging time constant of the capacitor is determined, it is difficult to easily change the frequency of the high voltage pulse on site. On the other hand, when the current limiting resistance value is lowered, the charging time constant becomes small, spark discharge is likely to occur successively, and necessary pulses having a predetermined pulse, pulse width and pulse frequency cannot be obtained.

An object of the present invention is to obtain a circuit configuration which eliminates the above-mentioned drawbacks by an inexpensive means.

Means for Solving the Problems A high-voltage ultrashort pulse power supply device of the present invention connects a primary side of a step-up transformer to a low-voltage AC power supply, and a high-side pulse generator through a rectifier on the secondary side of the step-up transformer. A high-voltage electrode having a voltage capacitor connected thereto, a pulse output terminal connected to one terminal of the high-voltage generating capacitor through a self-destructive spark switch, and another pulse output terminal connected to the other terminal of the capacitor. In the short pulse generating power supply, a control element having an on / off control function is connected between the AC power supply and the primary side of the step-up transformer, and a pulse current is detected between the capacitor and the other pulse output terminal. An element is provided, the output side of the pulse current detection element is connected to the control side of the control element, and the spark for each operation of the self-destruction type spark switch is detected to detect the on / off control. The control element is turned off to prevent the spark of the self-destruct switch from continuing.

Action The charging voltage charged in the high voltage capacitor is the spark voltage Vs
When the voltage reaches, a spark is generated in the spark gap, the high voltage capacitor is discharged through the pulse output terminals to which the load is connected, and a high voltage pulse is generated between the pulse output terminals. The discharge of the high-voltage capacitor at this time is detected by a pulse current detection element that intervenes between the capacitor and another pulse output terminal, and based on the detection current of this pulse current detection element, the primary side of the transformer is detected. The control element to be inserted is turned off to prevent the continuous and continuous flow phenomenon immediately after the spark discharge in the spark gap.

If further stated, the spark generation signal detected by the pulse current detection element is amplified by the amplifier and a part of the output is sent to the control signal generation circuit to control the signal from the control signal generation circuit. It is sent to the element to block the primary current of the transformer and prevent the continuous current and the continuous current immediately after the spark discharge.

At this time, another part of the output signal from the amplifier is sent to the error signal circuit, where the pulse generation phase set by the advance setting circuit and the target value of the pulse number are compared and The error signal is sent to the control signal generating circuit after being amplified and then sent to the control element on the primary side of the transformer to make the initial pulse generation phase and the number of pulses within the half cycle constant. .

EXAMPLE An example of the present invention will be described with reference to the accompanying drawings. FIG. 2 shows a basic circuit configuration of the present invention, which can be directly used as a power source for pulse charging of an electrostatic precipitator. Control elements 18 and 19 connected in antiparallel are inserted in the main circuit between the AC power source 1 and the transformer 2. In the example shown in the figure, the control elements 18 and 19 use power transistors, but instead of using them, thyristors, triacs or vacuum tubes may be used. Reference numeral 13 is a pulse current detection element for detecting the occurrence of spark discharge in the spark gap 9. Needless to say, the detection of the change in the voltage of the capacitor 8 may be used as the means for detecting the occurrence of the spark.

The spark generation signal detected by the detecting element 13 is an amplifier 14
Is amplified by, and a part of the output is supplied to the control signal generation circuit 17. The control signal generating circuit 17 immediately controls the control element 1 of the main circuit of the AC power supply by the signal from the amplifier 14.
A control signal for maximizing the impedance of 8 and 19 is sent to block the primary current of the transformer 2, thereby preventing the occurrence of spark discharge and the follow current.

Reference numeral 15 is a setting circuit for setting the phase for generating the first spark discharge in the half cycle and the number of pulses in the half cycle. The other output signal from the amplifier 14 is sent to the error amplification circuit 16, where the pulse generation phase set in the advance setting circuit 15 is compared with the target value of the pulse number, and the error signal is amplified. After that, it is sent to a circuit 17 for issuing control signals for the control elements 18, 19 of the primary circuit of the transformer 2 to form a feedback circuit.

A series resistor is not inserted in the capacitor 8 in FIG. 2, but a resistor having a small value for protection may be inserted instead of a large resistor for increasing the charging time constant.

When the capacitor 8 is charged in the vicinity of the peak value of the input voltage in this circuit configuration, rapid charging is performed and a large current is passed, which adversely affects the diode and the like. In such a case, the control elements 18 and 19 may be repeatedly turned on and off in a few hundreds of microseconds to charge them, and the circuit configuration of the error amplification circuit 16 can be made in this way. Further, the control elements 18 and 19 of the main circuit may be used as a dropper instead of the on / off operation.

By doing as in the above embodiment, the capacitor 8
The loss due to the conventional current limiting resistance when charging the battery is almost eliminated, and even when a self-destruction type spark switch is used, the initial pulse generation phase in the half cycle can be made almost constant, and the spark discharge continues. Therefore, it becomes possible to realize a pulse power supply that prevents the following current and the current flow at low cost.

FIG. 3 shows an embodiment of the present invention in the case of performing half-wave rectification, and 20 is the rectifier. The operation of this embodiment is the same as that of FIG. 2 described above, and since it is self-explanatory, description thereof will be omitted. As one of the application examples of the present invention, the inventor of the present invention has another invention "Particle charging device" (Japanese Patent Application No. 55-13211).
2) It can also be applied to the boxer charger power supply proposed in JP-A-57-56055. FIG. 4 shows an example thereof. In the figure, the parts having the same reference numerals and parts having the same reference numerals as those in the above-mentioned respective embodiments have the same part names and functions. The side has two sets of pulse output terminals 10, 11 and 10 ',
11 'are connected as shown in the figure, and one of the pulse output terminals 11 and 11' of each of these sets has an AC power supply 1'and a step-up transformer 21 with an intermediate tap for forming the main electric field of the boxer charger. The secondary side terminals are connected via current limiting resistors 22 and 22 ', respectively, and the output of the transformer 21 is applied between the electrodes of the boxer chargers facing each other from terminals 11 and 11', and the charging space between them is charged. Forming an alternating electric field for use. And terminal 11
When is near the negative peak value, the capacitor 8 which has been charged in advance through the rectifier 3 is discharged through the self-explosion spark gap 9 and a pulse high voltage is generated between the pulse output terminals 10 and 11, which is the terminal. 11 is applied between the opposing electrode elements of the boxer charger electrode to which one of the electrode elements can be connected to form plasma by streamer discharge, from which negative ions are emitted to the above-mentioned charged space.

At this time, since the rectifier 3'is blocked, the capacitor 8'is inactive. Next, when the polarity of the transformer 21 is reversed, the capacitor 8'is charged and discharged to generate a pulsed high voltage between the terminals 10 'and 11', and one electrode element is connected to 11 '. This is applied between the electrode elements, from which also negative ions are emitted into the charging space and thus dust particles impinging into the dust particles from both directions are rapidly charged.

EFFECTS OF THE INVENTION Since the present invention is as described above, the spark can be detected by the pulse current detection element for each operation of the self-destruction type spark switch, and then the detection element can detect the AC power supply and the primary side of the transformer. Since the control element inserted between the two can be turned off, it is possible to inexpensively realize the ultrashort pulse high-voltage power supply that prevents the continuous spark discharge and the continuous current in the above problems.

Further, when charging the high voltage capacitor, the loss due to the current limiting resistance is eliminated as compared with the case where the current limiting resistance is provided as in the conventional device.

Furthermore, even with a self-destruction type spark switch, the initial pulse generation phase in the half cycle can be made almost constant, and an ultrashort pulse high-voltage power supply that prevents continuous spark discharge and continuous current can be realized at low cost. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic circuit configuration of a conventional pulse charging power source for an electrostatic precipitator, FIGS. 2 and 3 are circuit diagrams showing an embodiment of the present invention, and FIG. 4 is a boxer charger of the present invention. It is a circuit diagram at the time of implementing into a power supply for use. The main elements in the figure are as follows. 1, 1 '... AC power supply (may be equipped with variable voltage element) 2 ... High-voltage transformer 3-6 ... Rectifier 7, 7' ... Current limiting resistor 8, 8 '... Capacitor 9, 9 '... Spark gap 10, 11 and 10', 11 '... Pulse output terminals 13, 13' ... Spark discharge detection element 14 ... Spark discharge detection signal amplification circuit 15 ... Within half cycle Initial spark discharge phase setting circuit and spark discharge generation frequency (pulse generation frequency) setting circuit 16 …… Error signal amplification circuit for target value set by circuit 15 ………… Main circuit control element control signal generation circuit 18, 19… … Main circuit control elements (transistors, thyristors, etc.) 20 …… Diode 21 …… Step-up transformer with intermediate tap 22,22 ′ …… Current limiting resistor

Claims (3)

[Claims] 1. A primary side of a transformer is connected to an AC power source, a high voltage capacitor for pulse generation is connected to a secondary side of the transformer via a rectifier, and one terminal of the high voltage generating capacitor is connected. In a high-voltage ultrashort pulse generation power supply in which a pulse output terminal is connected via a self-destruction type spark switch for continuously generating an ultrashort pulse, and another pulse output terminal is connected to the other terminal of the capacitor, A control element having an ON / OFF control function is connected between the AC power supply and the primary side of the transformer, and a pulse current detection element is provided between the capacitor and the other pulse output terminal, and the pulse current thereof is provided. A high-voltage ultrashort pulse power supply device characterized in that the output side of the detection element is connected to the control side of the on / off control element via a control signal generation circuit. 2. A control signal generating circuit and an amplifier are serially connected in series between the control element and the pulse current detecting element, and an error amplifier circuit is connected in parallel between the control signal generating circuit and the amplifier. Connected to the error amplification circuit is a circuit for setting the phase for generating the first spark discharge in the half cycle and the number of pulses in the half cycle. The pulse phase of 1. can be controlled by the control element, and the pulse generation frequency can be changed by turning on and off the control element. The high-voltage ultra-short pulse power supply device described in. 3. A primary side of a transformer is connected to an AC power source, and high voltage capacitors for pulse generation are connected to two sets of secondary side output side terminals of the transformer through rectifiers, respectively, and each high voltage A pulse output terminal is connected to one terminal of the generating capacitor through a self-destruction type spark switch for continuously generating an ultrashort pulse, and another pulse output terminal is connected to the other terminal of the capacitor, and the AC A control element having a control function for on / off is connected between the power source and the primary side of the transformer, and a pulse current detection element is provided between each capacitor and each of the other pulse output terminals. The output side of the pulse current detection element is connected to the control side of the on / off control element, and each of the step-up transformers with intermediate taps for forming the main electric field of the boxer charger is separately provided for each of the other pulse output terminals. Power supply high-voltage ultrashort pulses, characterized by connecting the following side terminals.