JP2013172493A - Pulse power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulse power supply device that is comprised of a combination of a plurality of stages of circuit units each being made up of a saturable reactor and a capacitor and sequentially transfers pulse to a rear stage unit, in which a voltage remains in a capacitor Cp of a terminal stage unit during the transfer and the capacitor Cp is discharged before the saturable reactor is saturated.SOLUTION: A switch section is connected in parallel to a capacitor Cp. The switch section is configured to maintain an on-state during an energy transfer and maintain an off-state until a voltage value of the capacitor Cp reaches a peak value from a peak voltage value of a capacitor Cpduring an energy transfer from the capacitor Cpdisposed at the front stage of the capacitor Cp to the capacitor Cp.

Description

  The present invention relates to a pulse power supply device, and more particularly, to a pulse power supply device capable of shortening a pulse by reducing a prepulse voltage.

  A pulse power supply device used for pulse laser excitation, pulse plasma generation, or the like is known from Patent Document 1, Patent Document 2, and the like. FIG. 6 shows a circuit configuration diagram of a conventional pulse power supply, in which a DC voltage is stored in a capacitor C0 for energy storage in the first stage circuit unit via a charger Ch. When energy is supplied to the load, the switching element Sw made of IGBT or the like is turned on, and the saturable reactor SR1 is saturated. The stored and accumulated energy is transferred to the capacitor C1 through the transformer TC1.

  Thereafter, the saturable reactor SR2 of the second-stage circuit unit is saturated, whereby a loop current II flows and the stored energy is transferred to the capacitor C2. Next, the saturable reactor SR3 in the third stage (final stage circuit unit) is saturated, so that a loop current of III flows, and the accumulated energy is transferred to the capacitor Cp of the final stage circuit unit, and is transferred to the discharge tube DT. Is injected.

JP-A-5-291889 JP 7-22918

  In the pulse power supply circuit as shown in FIG. 6, in order to obtain a required pulse width, a plurality of combination circuits of saturable reactors and capacitors are provided in a ladder shape, but when the output voltage is required to be shortened, the capacitor C0 , C1, C2, Cp, especially the capacitance C of the capacitor Cp needs to be reduced. However, the impedance of the capacitors C 0, C 1, C 2, and C p becomes smaller as C becomes smaller than the calculation formula 1 / ωC.

  As shown in the waveform diagram at the time of pulse transfer in FIG. 7, for example, in the transfer period of the loop II in which energy is transferred from the capacitors C1 to C2, energy commutates to the capacitors C1 to Cp, and the voltage Vr remains in the capacitor Cp. . Hereinafter, this residual voltage Vr is referred to as a pre-pulse voltage. The pre-pulse voltage Vr affects the discharge phenomenon of the capacitor Cp before the saturation of the saturable reactor SR3 of the final stage unit. For this reason, there has been a limit to reducing the capacitor capacity in order to make the output voltage shorter. Note that Patent Documents 1 and 2 do not describe a problem regarding reduction of the prepulse voltage.

  An object of the present invention is to provide a pulse power supply device that can realize a shorter pulse by reducing the pre-pulse voltage.

In the present invention, a circuit unit composed of a saturable reactor and an energy storage capacitor is combined in a plurality of stages, and is stored in the energy storage capacitor of the first stage circuit unit by turning on the switching element connected in series with the first stage energy storage capacitor. The energy stored in the energy storage capacitor of the final circuit unit is supplied to the discharge tube by sequentially transferring the stored energy to the energy storage capacitor of the subsequent circuit unit via the saturable reactor. In the composition,
In parallel with the energy storage capacitor of the final circuit unit, a switch unit that is kept on during energy transfer is connected, and a switch control unit that detects the energy storage capacitor of the final circuit unit is provided to control the switch. When the voltage at the time of energy transfer from the energy storage capacitor of the circuit unit immediately before the final circuit unit to the energy storage capacitor of the final circuit unit reaches a predetermined value, the switch unit turns on the switch unit. And the off period is continued to the vicinity of the peak value voltage of the energy storage capacitor of the final stage circuit unit.

  A second aspect of the present invention is characterized in that the switch section is constituted by a series body of a reactor and a switch.

  According to a third aspect of the present invention, the predetermined value of the voltage by the switch control unit is a peak value of the capacitor voltage for energy storage of the circuit unit one stage before the final stage circuit unit or a voltage in the vicinity of the peak value. It is characterized by.

  According to a fourth aspect of the present invention, the voltage detected by the switch controller is a terminal voltage of a saturable reactor of the final stage circuit unit instead of the capacitor voltage for storing energy of the final stage circuit unit. It is.

  According to a fifth aspect of the present invention, the switch unit uses a magnetic switch made of a saturable reactor.

As described above, according to the present invention, the off period is continued from the vicinity of the peak voltage of the capacitor Cp ₋₁ (C2) one stage before the final stage capacitor Cp until the voltage of the final stage capacitor Cp becomes near the peak value. However, it is in the on state during other transfers,
Since the transferred energy flows through the switch unit connected in parallel with the capacitor Cp during the period in which the prepulse voltage is generated, the prepulse voltage generated in the capacitor Cp becomes small.

  Further, when energy transfer from the capacitor C2 to Cp is started, the switch part is turned off, so that all energy is transferred from the capacitor C2 to Cp, and the energy transfer efficiency is improved. The output voltage can be made shorter.

The circuit block diagram which shows embodiment of this invention. The wave form diagram of an energy transfer state. The circuit block diagram which shows other embodiment of this invention. The wave form diagram of an energy transfer state. The block diagram of the switch part which shows other embodiment of this invention. The circuit block diagram of the conventional pulse power supply device. The wave form diagram of the conventional energy transfer state.

  In the present invention, in order to suppress the pre-pulse voltage in the capacitor Cp of the final circuit unit remaining at the time of pulse transfer in the pulse power supply device, a switch unit is connected in parallel with the capacitor Cp, and energy is stored in the capacitor Cp. Therefore, the generation of the pre-pulse voltage is suppressed by turning on the switch unit at the time of pulse transfer other than the target operation for the purpose, and turning off the switch unit only when the purpose of transfer is energy storage in the capacitor Cp. This will be described in detail below based on examples.

  FIG. 1 is a block diagram showing a first embodiment of the present invention, and the same or corresponding parts as those of the circuit component shown in FIG. However, in FIG. 1, a combination of a saturable reactor as a magnetic switch for obtaining a required pulse width and a ladder circuit of a capacitor for storing energy is SR1, C1, SR2 and C2, and SR3 and Cp. Although a stage circuit unit is used, it is needless to say that the number of combined units may be any plural stage unit.

  In the first embodiment, the switch unit 20 is connected in parallel with the capacitor Cp of the final stage circuit unit. In this embodiment, the switch unit 20 includes a reactor L1 and a switch SW1 made of an electron tube such as a thyratron or a semiconductor element such as an IGBT. In addition, a switch control unit 1 for the switch SW1 is provided, and the switch control unit 1 includes a voltage detection unit 2, a comparator 3, and an output control unit 4. The voltage detector 2 detects the peak voltage of the capacitor C2 that is one stage before the final circuit unit, and the detected voltage is input to one terminal of the comparator 2. A set value set in advance to a value close to the peak voltage value of the capacitor C2 is input to the other terminal of the comparator 2, and a signal is output when the detected voltage reaches a predetermined value.

  The output control unit 4 uses the input signal from the comparator 2 as a trigger and outputs a signal for keeping the switch SW1 off for a predetermined time required to transfer energy from the capacitor C2 to the capacitor Cp. The predetermined time for keeping the switch SW1 off is set in advance from the core saturation characteristics of the saturable reactor SR3. As will be described later, the switch SW1 is in an on state except for the transfer loop III, and is controlled to be in an off state only during the transfer loop III.

Here, if the pulse width of the output voltage desired to be targeted is a, the resonance frequency π√ (LC) determined by the capacitance C of the capacitors C2 and Cp and the reactance L of the saturable reactor SR3 is set so as to satisfy the equation (1). To do.
a / 2 = π√ {L · (C 2 · C p) / (C 2 + C p)} (1)
Further, the value of the reactor L1 connected in series with the switch SW1 is set so as to satisfy the equation (2).
a / 2 = π√ (C2 · Cp) (2)
The operation of the present invention configured as described above will be described with reference to FIG.
Normally, the switch SW1 is kept on and the switch unit 20 is connected in parallel to the capacitor Cp. At the time of energy transfer, the saturable reactor SR1 is saturated as in the prior art, so that the energy stored in the capacitor C0 of the first stage circuit unit is transferred to the capacitor C1 by the transfer loop I. Thereafter, the saturable reactor SR2 of the second stage circuit unit is saturated, whereby a loop current II flows and the energy stored in the capacitor C1 is transferred to the capacitor C2.

  At the time of the transfer loop II, the voltage detector 2 detects the charging voltage of the capacitor C2, and the comparator 3 compares the charging voltage with the set value, and the voltage of the capacitor C2 is close to the set peak value. Signal is output, and the switch SW1 is switched from on to off via the output control unit 4. The off period III of the switch SW1 is controlled from off to on after a predetermined time set in advance from the saturation characteristic of the iron core of the saturable reactor SR3 as shown in FIG.

  That is, as a result, the off period continues from the vicinity of the peak voltage of the capacitor C2 until the voltage of the capacitor Cp at the final stage is close to the peak value, and then turned back on. For this reason, during the off time III, the peak value voltage of the capacitor Cp may be directly detected and switched from off to on when it is close to the peak value.

  As described above, when the switch SW1 is turned on during the pre-pulse voltage generation period during the transfer of energy from the capacitor C1 to the capacitor C2, the energy is transferred through the route C1 → L1 → C1, and the capacitor of the final stage unit. The pre-pulse voltage generated at Cp is reduced. Since the switch SW1 is in the OFF state after the energy transfer from the capacitor C2 to Cp is started, energy transfer by the loop of C2 → L1 → C2 is prevented, and the energy transfer efficiency from the capacitor C2 to Cp is improved. It is.

  FIG. 3 is a block diagram showing the second embodiment. The difference from FIG. 1 is that the voltage across the saturable reactor SR3 of the final stage unit is detected at the voltage detection position. Accordingly, the switch control unit 10 includes a voltage detection unit 11, a saturation point detection unit 12, and an output control unit 13. Other configurations are the same as those in FIG.

  The saturation point detector 12 calculates and stores the saturation point from the voltage / time area Vt of the saturable reactor SR3 in advance. Then, the voltage detected by the voltage detection unit 11 is input to calculate a saturation point, and when the calculated value reaches the stored value, it is determined that it is saturated and is output to the output control unit 13. Then, the switch SW1 in the on state is turned off. FIG. 4 shows this state, and the switch SW1 is kept off during the period of the transfer loop III.

  Therefore, in the second embodiment, as in the first embodiment, when the switch SW1 is turned on during the pre-pulse voltage generation period during the transfer of energy from the capacitor C1 to the capacitor C2, the energy is changed from C1 → L1 → C1. And the pre-pulse voltage generated in the capacitor Cp of the final stage unit is reduced. Since the switch SW1 is in the OFF state after the energy transfer from the capacitor C2 to Cp is started, energy transfer by the loop of C2 → L1 → C2 is prevented, and the energy transfer efficiency from the capacitor C2 to Cp is improved. It is.

  FIG. 5 shows an embodiment in which a saturable reactor SR is used as the switch unit 20 as a magnetic switch. The saturable reactor SR includes an exciting coil RC for performing a switching operation, and a power source E and a switch SW are connected in series to the exciting coil RC. When the switch SW is turned on, a direct current is supplied to the exciting coil RC. Saturable reactor SR is saturated by passing an electric current.

  The timing at which the saturable reactor SR is saturated is in the vicinity of the peak voltage of the capacitor C2 at the time of energy transfer from the capacitor C2 to Cp. Let saturation continue. Note that the switch control unit 1 shown in FIG. 1 or the switch control unit 10 shown in FIG. 4 is used as an on / off command for the switch SW connected in series with the exciting coil RC.

  Therefore, in this embodiment, by turning on the switch SW in the pre-pulse voltage generation period during which energy is being transferred from the capacitor C1 to the capacitor C2, the energy is transferred through the route C1 → SR → C1, and the capacitor of the final stage unit. The pre-pulse voltage generated at Cp is reduced. Further, since the switch SW is in the OFF state after the energy transfer from the capacitor C2 to Cp is started, energy transfer by the loop of C2 → SR → C2 is prevented, and the energy transfer efficiency from the capacitor C2 to Cp is improved. It is.

DESCRIPTION OF SYMBOLS 1,10 ... Switch control part 2,11 ... Voltage detection part 3 ... Comparator 4,13 ... Output control part 12 ... Saturation point detection part 20 ... Switch part SR, SR1-SR3 ... Saturable reactor C1, C2, Cp ... Capacitor L1 ... Reactor SW ... Switch

Claims (5)

By combining multiple stages of circuit units consisting of a saturable reactor and an energy storage capacitor, and turning on the switching element connected in series with the first-stage energy storage capacitor, the energy stored in the first-stage energy storage capacitor is converted into a saturable reactor. In order to compress the pulse by sequentially transferring to the energy storage capacitor of the next stage circuit unit via, and to supply the energy stored in the energy storage capacitor of the final circuit unit to the discharge tube,
In parallel with the energy storage capacitor of the final circuit unit, a switch unit that is kept on during energy transfer is connected, and a switch control unit that detects the energy storage capacitor of the final circuit unit is provided to control the switch. When the voltage at the time of energy transfer from the energy storage capacitor of the circuit unit immediately before the final circuit unit to the energy storage capacitor of the final circuit unit reaches a predetermined value, the switch unit turns on the switch unit. The pulse power supply device is characterized in that the off-period is switched to the off-state and the off-period is continued to the vicinity of the peak value voltage of the energy storage capacitor of the final stage circuit unit. 2. The pulse power supply device according to claim 1, wherein the switch unit is configured by a series body of a reactor and a switch. 2. The predetermined value of the voltage by the switch control unit is a peak value of an energy storage capacitor voltage of a circuit unit one stage before the final stage circuit unit, or a voltage in the vicinity of the peak value. 2. The pulse power supply device according to 2. 4. The voltage detected by the switch control unit is a terminal voltage of a saturable reactor of a final stage circuit unit, instead of a capacitor voltage for energy storage of the final stage circuit unit. Is a pulse power supply. 5. The pulse power supply device according to claim 1, wherein the switch unit uses a magnetic switch made of a saturable reactor.

Images