KR100343983B1 - The output control and protection circuit for high voltage and large current pulse generator - Google Patents

Abstract

The present invention relates to an output control and protection circuit of a high voltage, high current pulse generator, and a spark gap switch or a cyclotron switch, which is conventionally used as a high voltage / high current switch, has a very short lifespan, and a pulse transformer has a large value. With distribution capacity and primary and secondary leakage reactance, it is difficult to limit pulse rise time and short pulse width output, and there is a risk of switch breakage due to very large current flow in high voltage / high current switch in case of load short-circuit. Since the rating is fixed and the switch is not a semiconductor switching device, it is difficult to arbitrarily adjust the pulse output form, which makes it difficult to optimally respond to the load. Therefore, the present invention stores the charging energy in the capacitor, and generates a pulse of high voltage, high current by a pulse transformer connected in series with a general-purpose semiconductor device connected in parallel to generate a pulse to the load unit 110 to generate a pulse The unit 109, the pulse voltage rise time UT and the pulse voltage fall time AT are arbitrarily controlled to soft-start the pulse output of the pulse generator 109 to protect the load. By varying the pulse reference voltage (RV), pulse width (DF), and pulse frequency (PF), it is possible to generate pulse power of different outputs for optimum response to various load conditions, and pulses from overcurrent by overcurrent detection control It consists of a charge / control unit 101 to protect the device of the switch, preventing damage of the pulse switch device from overvoltage and overcurrent, and optimally responds to various load conditions. It is to be done.

Description

Output control and protection circuit of high voltage and high current pulse generators {THE OUTPUT CONTROL AND PROTECTION CIRCUIT FOR HIGH VOLTAGE AND LARGE CURRENT PULSE GENERATOR}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse generator for generating pulses having a pulse width of several tens [ns] to several hundreds [ns] at high voltages (over several tens of kV) and large currents (over hundreds of A). The present invention relates to an output control and protection circuit of a high voltage, high current pulse generator that can cope with and protect a pulse switch device from over voltage and over current.

High-voltage, high-current pulse power technology draws energy stored in capacitors, inductors, etc. in tens of [ns] to hundreds of [ns] and concentrates the energy to the required load in a short time.

When electrical energy is released in such a short time, extreme conditions such as ultra-high temperature, super-magnetic field, and ultra-high field, which are not normally realized, can be easily realized. Therefore, pulse power generation technology uses laser, microwave, X-ray, electron acceleration, and nuclear fusion. It is a key technology that is rapidly spreading in various industries such as generation, electron beam generation, rock / building blasting and low temperature plasma generation.

1 is a circuit configuration diagram of a pulse generator using a conventional spark gap switch or a cyclotron switch. As shown in FIG. 1, a DC high voltage generator 1 for generating a DC high voltage when a commercial power source is input, A high voltage / large current switch for conducting a high voltage charging capacitor 3 to charge the DC high voltage generated by the DC high voltage generator 1 and the electrostatic energy charged in the high voltage charging capacitor 3 to output a pulse in a short instant. (4) and a pulse transformer 5 which insulates and boosts the energy output from the high voltage charging capacitor 3 and outputs a high voltage / high current pulse to the load unit 6.

Referring to the prior art configured as described above in detail.

When the commercial power is input, the DC high voltage generator 1 generates a DC high voltage.

The generated DC high voltage charges the high voltage charging capacitor 3 through the blocking diode 2.

This charged energy is briefly conducted by a high voltage / high current switch 4, such as a spark gap switch or a thyratron switch, to be input to the pulse transformer 5 in the form of a pulse. It is insulated and stepped up by the pulse transformer 5 and outputs a high voltage / high current pulse to the load part 6.

By the operation as described above, the load unit 6 generates a pulse having a pulse width of several tens [ns] to several hundreds [ns] at a high voltage (several tens of kV or more) and a large current (several hundreds of A (amps) or more).

At this time, the equivalent circuit of the pulse transformer 5 is configured as shown in Fig. 2, but the reason for this configuration is as follows.

As the pulse itself is very high frequency and the primary and secondary windings of the pulse transformer 5 have the values of N1 and N2 for boosting, there are large distribution capacities Cd1 and Cd2 between the primary and secondary windings. This is because large primary and secondary leakage reactances Xl1 and Xl2 exist because the primary and secondary windings do not completely wrap the core.

However, in the prior art as described above, firstly, a spark gap switch or a cyclotron switch used as a high voltage / large current switch has a very short lifespan, and thus has a problem of field application limitation. Second, a pulse transformer has a large value. By having distribution capacity (Cd1, Cd2) and large 1st and 2nd leakage reactance (Xl1, Xl2), it is difficult to limit pulse rise time and short pulse width output, and such pulse rise slope and pulse width limit are transmitted to the load. Reduced transmission energy and power efficiency are reduced. For example, in the low temperature plasma generation field used in the environmental industry, since the pulse width is sufficient for several tens of [ns], all of them have a problem of high operating cost by reducing power efficiency by acting as a loss.

Third, there is a risk of damage to the switch due to the very large current flowing to the high voltage / high current switch during the load short circuit. Fourth, the rating of the switch and the pulse transformer is fixed and the switch is not a semiconductor switching device. It is difficult to adjust voltage, pulse width, pulse frequency, etc. at random, which makes it difficult to optimally respond to the load.

Therefore, an object of the present invention for solving the conventional problems as described above is to design a switch by connecting a number of semi-permanent general-purpose switch elements in parallel, and connected in series with a pulse transformer with a winding ratio of 1: 1, the first and second The present invention provides an output control and protection circuit for a high voltage, high current pulse generator to minimize the leakage reactance and distribution capacity of the winding.

Another object of the present invention is to control the output voltage of the high voltage, high current pulse generator to soft start the pulse output to protect the system by arbitrarily controlling the pulse rise time, pulse reference voltage and pulse fall time for high voltage, high current pulse And providing a protection circuit.

Another object of the present invention is to control and protect the output of the high voltage, high current pulse generator to enable optimal operation by generating a pulse according to various load conditions by varying the pulse width and pulse frequency for the pulse of high voltage, high current In providing a circuit.

Another object of the present invention is to reduce the overvoltage caused by the excitation energy and load energy reflection of the pulse transformer, and to detect and control the overcurrent of the load to protect the pulse switch element output control and protection circuit of the high voltage, high current pulse generator In providing.

1 is a circuit diagram of a pulse generator of a high voltage and high current using a conventional spark gap switch or a cyclotron switch.

2 is an equivalent circuit diagram of a pulse transformer in FIG.

3 is a circuit diagram of a pulse generator of a high voltage high current using a conventional general-purpose semiconductor switch element.

Figure 4 is a block diagram of the output control and protection circuit of the high voltage, high current pulse generator of the present invention.

5 is an input / output signal waveform diagram of each part in FIG. 4;

6 is a waveform diagram of charging voltage and charging current of the pulse discharge capacitor Cp in FIG. 4.

7 is a diagram of the primary voltage waveform of the pulse transformer (P / T) in the absence of a clipping circuit in FIG.

8 is a diagram of the primary voltage waveform of the pulse transformer (P / T) with the clipping circuit in FIG.

***** Explanation of symbols for the main parts of the drawing *****

101: charge / control unit 102: voltage conversion unit

103: voltage controller 104: switching controller

105: command control unit 106: overcurrent protection circuit unit

107: display and key control panel

108: current detector 109: pulse generator

110: load portion Cc: charging capacitor

Cs: Snubber Capacitor Cp: Pulse Discharge Capacitor

Dc: clipping diode Rs: snubber resistor

Rc: Clipping Resistance P / T: Pulse Transformer

Switch_c: Charging Switch Switch_p: Pulse Switch

The present invention for achieving the above object is a pulse generating means for storing the charging energy in the capacitor, and generates a pulse of high voltage and high current by the pulse transformer connected in series with a general-purpose semiconductor device connected in parallel to the load side, and pulse rise By controlling the time, pulse reference voltage and pulse falling time arbitrarily, the load is protected by soft-starting the pulse output of the pulse generating means, and the pulse width and pulse frequency are variably adjusted to generate pulses of different outputs. It is characterized in that it comprises a charge / control means to protect the elements of the pulse switch from overvoltage and overcurrent in response to various load conditions optimally.

Hereinafter, with reference to the accompanying drawings in detail as follows.

4 is a circuit diagram illustrating a pulse generator for overvoltage and overcurrent protection according to the present invention. As shown in FIG. 4, charge energy is stored in a capacitor, and a high voltage, The pulse generator 109 with an overvoltage protection circuit for generating a large current pulse and generating it to the load unit 110, and the pulse voltage rise time (UT) and the pulse voltage fall time (AT) are arbitrarily controlled to generate the pulse. Soft-starting of the pulse output of the unit 109 to protect the load, and by adjusting the pulse reference voltage (RV), pulse width (DF) and pulse frequency (PF) optimizing for various load conditions Correspondingly, the charging / control unit 101 is configured to protect the element of the pulse switch from the overcurrent by the overcurrent detection control.

In the above, the charge / control unit 101 converts an input AC power into a DC voltage or converts an input DC voltage into a DC voltage and charges the charging capacitor Cc to an AC / DC converter and a DC / DC converter. (102), a charge switch (Switch_c) for transmitting or cutting off the voltage of the charging capacitor (Cc) to the next stage, a current detector 108 for sensing the current flowing in the load unit 110, and a control signal of the reference values The display and key operation unit 107 for providing a signal, and the optimum pulse rise time (UT), pulse fall time (AT), and pulse reference voltage (RV) to correspond to the operating conditions of the load by the control signals provided above. , A command controller 105 for outputting a pulse width DF and a pulse frequency PF, a pulse rising time UT, a pulse falling time AT, and a pulse reference voltage RV outputted to the command controller 105. The conversion unit 102 by controlling the charging capacitor (Cc) The charge switch (Switch-C) and the pulse switch (Switch-) to have a voltage control unit 103 for adjusting the voltage to be charged, and a pulse width DF and a pulse frequency PF output from the command control unit 105. The switching control unit 104 for controlling the on / off operation of P) and the command control unit 105 to block the operation of the pulse switch (Switch-P) if the current detected by the current detector 108 is an overcurrent. The alert includes an overcurrent protection circuit 106.

The pulse generator 109 includes a pulse transformer P / T for generating a pulse of high voltage and high current, M modules connected in parallel to a primary side of the pulse transformer P / T, and outputs a large current, The secondary side of the pulse transformer P / T is connected in series so as to generate a high voltage.

Referring to the operation and effect of the present invention configured as described in detail as follows.

FIG. 3 is a circuit diagram of a pulse generator of a high voltage and high current using a general-purpose semiconductor switch element. As shown therein, a pulse discharge capacitor 12 and a pulse switch (Char) for charging a charging voltage Vo supplied from a charging device are shown. 13) are connected in series to form one branch (14), and these branches are connected in parallel in parallel, and this parallel connection circuit is connected to the primary winding of the pulse transformer (11) to connect one module (15). N identical modules are configured and secondary windings of the pulse transformers 11 of each module are connected in series.

Looking at the operation of the circuit configured as described above, if the charging voltage (Vo) is supplied from the charging device not shown, the voltage is charged to the pulse discharge capacitor 12 in the state that the pulse switch 13 is turned on.

Here, the pulse switch 13 is used by connecting M general-purpose semiconductor switch elements in parallel instead of the spark gap switch.

The energy charged in the pulse discharge capacitor 12 is routed through the pulse switch 13, and transfers energy to the primary side of the pulse transformer 11.

At this time, since M branches are connected in parallel to the module 15, the voltage passing to the primary side of the pulse transformer 11 becomes Vo, and the current becomes M times of Io.

Therefore, the voltage seen at the load is N times Vo, and the current is M times Io.

That is, in order to obtain a large current, the branches are connected in parallel to form the module 15, and in order to obtain a high voltage, the N primary sides of the pulse transformer 11 are connected in series.

By the operation as described above, pulses of high voltage and high current are generated by pulse transformers connected in series to the secondary side on the load side and branches connected in parallel to the primary side of the pulse transformer.

As a result, the high voltage Vout supplied to the load side becomes Vout = N * Vo, and the large current Io becomes Io = M * Io.

By protecting the pulse generating circuit which supplies the high voltage high current pulse to the load during the load short-circuit and opening, and enabling the high speed control by the optimal operation control, the life of the semiconductor switch element is protected, It is to ensure high reliability by preventing damage, which will be described based on FIG. 4 as follows.

DC voltage through a commercial AC power or a battery is supplied to the AC / DC conversion and DC / DC converter 102.

At this time, the display and key operation unit 107 outputs a control signal of the reference values to the command control unit 105.

Then, the command controller 105 outputs the pulse rising time UT, the pulse falling time AT, and the pulse reference voltage RV to the voltage controller 103 according to the control signal, and the pulse width DF and the pulse. The frequency PF is output to the switching controller 104.

Accordingly, the voltage controller 103 may have values such as a pulse rising time UT, a pulse falling time AT, and a pulse reference voltage RV, as shown in FIG. 5B. The operation / stop switch signal as shown in the figure is provided to the AC / DC conversion and DC / DC conversion unit 102.

At this time, the voltage control unit 103 controls until the voltage "0".

Therefore, the AC / DC conversion and DC / DC converter 102 converts the commercial AC power into DC voltage when the commercial AC power is input and outputs it to the charging capacitor Cc, or converts it into AC power when DC voltage is input. Is converted into a DC voltage again and output to the charging capacitor Cc.

Then, the charging capacitor Cc is charged with the voltage as shown in FIG.

At the same time, the switching controller 104 receives the pulse width DF and the pulse frequency PF to control the charging switch Switch_c and the pulse switch Switch_p of the pulse generator 109.

That is, the switching controller 104 outputs a pulse as shown in FIG. 5C to the charge switch Switch_c so as to alternately turn on / off with a dead time between the two switches (Switch_c). The pulse switch as shown in (d) of FIG. 5 is output to the pulse switch Switch_p.

When the charging switch Switch_c is turned on and the pulse switch Switch_p is turned off, the voltage charged in the charging capacitor Cc is charged in the pulse discharge capacitor Cp through the charging switch Switch_c. After a predetermined dead time has elapsed, when the charging switch Switch_c is turned off and the pulse switch Switch_p is turned on, the energy charged in the pulse discharge capacitor Cp is converted into a pulse transformer P / of the pulse generator 109. Is induced in each primary winding of T).

The induced voltage is operated synchronously in all modules, and since the N secondary windings of the pulse transformer (P / T) are connected in series, as a result, the voltage of the primary induced voltage * N times is ultimately applied to the load unit 110. Is output.

In addition, since each module's pulse switches (Switch_p) are connected in parallel, each module can handle a current equal to the output current so that a large current can flow.

Here, the reason for having the pulse rise time UT is that the voltage charged in the pulse discharge capacitor Cp is charged in the charge capacitor Cc by the resonance phenomenon between the charge inductor Lc and the pulse discharge capacitor Cp. This is to prevent the induction of twice the voltage and to soft-start to prevent unexpected impact on the load unit 110.

The reason why the charging inductor Lc is used is to prevent the efficiency from dropping when the current limiting resistor is used during charging, which causes a loss in the resistance, thereby lowering the efficiency of the entire apparatus.

In addition, the reason why the voltage of the capacitors is '0' with the pulse fall time (AT) in the above is to prevent the electric shock of the user and to operate the device stably by resetting the energy stored in all the capacitors at the end of the operation.

In addition, the pulse generator 109 is configured with an overvoltage protection circuit to prevent the pulse switch (Switch_p) is induced in the overvoltage, this protection operation is as follows.

In FIG. 4, as shown in FIG. 7, the excitation energy and the load side reflection energy of the pulse transformer P / T are at the moment when the pulse switch Switch_p of the pulse generator 109 is turned off. A large back swing (forward) voltage appears in the primary winding of the pulse transformer P / T.

This voltage is added to the voltage remaining in the pulse discharge capacitor (Cp) and the polarity, which can be caused across the pulse switch (Switch_p) of the device damage.

In order to prevent such a device from being damaged, the clipping diode Dc and the clipping resistor Rc are connected in parallel to the primary winding of the pulse transformer P / T, and at the moment when the pulse switch Switch_p is turned off, the pulse transformer ( Excitation energy and load-side reflected energy of P / T are consumed by clipping resistance (Rc) to protect the device.

As such, the excitation energy and the load side reflection energy of the pulse transformer P / T are consumed by using the clipping diode Dc and the clipping resistor Rc, so that the voltage characteristics appearing in the primary winding of the pulse transformer P / T are reduced. Looking at it, it can be seen that almost no back swing as shown in FIG.

The snubber capacitor Cs and the snubber resistor Rs connected to the pulse switch Switch_p reduce the spike voltage induced in the switch_p.

In addition, the charge / control unit 101 is configured with an overcurrent protection control circuit to protect the pulse switch (Switch_p) from the overcurrent, the operation thereof is as follows.

If the load unit 110 is a plasma reactor, under certain operating conditions, energy may be excessively drawn to generate an ike. In addition, an accident such as a short circuit in the reactor electrode may occur.

At this time, if the output current of more than rated flows to the load unit 110, the current flows to the pulse switch (Switch_p) as it is.

However, this current is the current flowing for a very short time (about tens [ns]), and thus the conventional track control that detects it and turns off the pulse switch (Switch_p) is impossible.

Therefore, in the present invention, the pinch-off effect of the pulse switch Switch_p is used.

That is, when the fault current flows, the driving voltage is set to saturate the pulse switch (Switch_p) to prevent damage to the pulse switch.

At this time, since the charging voltage of the pulse discharge capacitor Cp falls above the rated value, as shown in the lower part of FIG. 6 during the next cycle, when a large charging current of more than the rated current flows, the current detector 108 of FIG. The overcurrent protection circuit unit 106 is transmitted.

Then, the overcurrent protection circuit 106 determines whether there is an overcurrent, and if it is determined that the overcurrent is notified to the command control unit 105, the operation of the charge switch (Switch_c) and the pulse switch (Switch_p) is shut off to stop the operation of the entire device. Protect.

The situation is then displayed on the display and key operation unit 107 so that the device can take protective measures.

As described in detail above, the pulse voltage, pulse width, and pulse frequency for high voltage and high current pulses are variably adjusted to generate pulses suitable for various load conditions, thereby enabling optimal operation, and excitation energy and load side reflection of the pulse transformer. There is an effect that the pulse switch element is protected by overvoltage suppression and overcurrent protection control by energy.

Claims (8)

Pulse generating means for storing charging energy in the capacitor and generating pulses of high voltage and high current to the load side by pulse transformers connected in series with general-purpose semiconductor elements connected in parallel, pulse voltage rising time, pulse voltage holding time and pulse By arbitrarily controlling the voltage fall time to protect the load by soft-starting the pulse output of the pulse generating means, and by varying the pulse voltage, pulse width and pulse frequency, the optimum response to various load conditions, An output control and protection circuit for a high voltage, high current pulse generator, comprising charge / control means for protecting the element of the pulse switch from over current by over current detection control. The method of claim 1, wherein the charging / control means includes an AC / DC conversion and a DC / DC conversion unit for converting an input commercial AC power into a DC voltage or converting an input DC voltage into a DC voltage to charge the charging capacitor. A charge switch for charging the voltage of the charging capacitor to the pulse discharge capacitor of the pulse generating means, a current detector for sensing a current flowing through the pulse discharge capacitor, a display and key operation unit for providing control signals of reference values; Command control unit for outputting the optimum pulse rise time, pulse fall time, pulse reference voltage, pulse width and pulse frequency to correspond to the operating conditions of the load by the control signal provided by the; and pulse rise time output from the command controller The voltage is charged in the charging capacitor by controlling the converter by a pulse fall time and a pulse reference voltage. A voltage controller to control the on / off operation of the charging switch and the pulse switch to have a pulse width and a pulse frequency output from the command controller, and a pulse switch if the current detected by the current detector is an overcurrent Output control and protection circuit of a high voltage, high current pulse generating device, characterized in that it comprises an overcurrent protection circuit to inform the command control unit to block the operation of. 3. The output control and protection circuit of claim 2, wherein a charge inductor is connected between the charge switch and the current detector to limit the current. The high voltage and high current according to claim 1, wherein the pulse generating means comprises a pulse transformer for generating a pulse of high voltage and high current, and M modules connected in parallel to the primary side of the pulse transformer to output a large current. Output control and protection circuit of pulse generator. 5. The output control and protection circuit of claim 4, wherein the module includes a pulse discharge capacitor for charging energy, and a pulse switch for controlling a discharge operation of the pulse discharge capacitor. . 6. The output control and protection circuit of claim 5, wherein the pulse switch is configured to reduce the spike voltage by connecting the snubber capacitor and the snubber resistor connected in series. 5. The output control of the high voltage, high current pulse generator according to claim 4, wherein the pulse transformer is configured to connect a clipping diode and a clipping resistor to the primary winding thereof in parallel to consume excitation energy to prevent breakage of the pulse switch. Protection circuit. 5. The output control and protection circuit of a high voltage, high current pulse generator as claimed in claim 4, wherein the pulse transformer is configured to output high voltage pulses by connecting N secondary units in series.