阅读说明：本技术 直流脉冲电源装置以及直流脉冲电源装置的占空比控制方法 (DC pulse power supply device and duty ratio control method for DC pulse power supply device ) 是由 让原逸男 安达俊幸 米山知宏 宫嵜洸一 于 2019-11-08 设计创作，主要内容包括：本发明的直流脉冲电源装置在脉冲动作的起动时,在直到电容器电压被充电至足以将直流电抗器的磁饱和复位的电压为止的期间,控制斩波电路的脉冲动作的占空比,使开关元件成为接通状态而使直流电抗器成为通电状态的脉冲宽度可变。通过逐渐增加脉冲宽度来抑制直流电抗器电流的增加程度,将直流电抗器电流抑制在磁饱和电平以下。由此,在脉冲动作的起动时,抑制直流电抗器的磁饱和。(The present invention provides a direct current pulse power supply device, which, at the start of a pulse operation, controls the duty ratio of the pulse operation of a chopper circuit until a capacitor voltage is charged to a voltage sufficient to reset the magnetic saturation of a direct current reactor, and which can vary the pulse width by turning a switching element on and turning the direct current reactor on. The pulse width is gradually increased to suppress the increase of the DC reactor current, thereby suppressing the DC reactor current to be less than or equal to the magnetic saturation level. This suppresses magnetic saturation of the DC reactor at the start of the pulse operation.)

1. A DC pulse power supply device is characterized by comprising:

a direct current power supply;

a pulse unit connected to the dc power supply and generating a pulse output by a boost chopper circuit including a series circuit of a dc reactor and a switching element;

a voltage clamp unit including a capacitor connected in parallel to the dc reactor of the pulse unit, the voltage clamp unit limiting a voltage across the dc reactor to a clamp voltage by a capacitor voltage of the capacitor; and

a control circuit unit for controlling the switching operation of the switching element of the pulse unit,

the control circuit unit includes a pulse pattern control unit for controlling a pulse operation of a pulse pattern for generating a pulse output at a constant cycle,

the pulse mode control unit includes a duty control unit for varying a pulse width,

the duty control unit gradually increases a pulse width of the dc reactor in an energized state by closing the switching element at an initial stage of the pulse operation.

2. The direct current pulse power supply device according to claim 1,

the duty control unit has an initial duty value at the start of the pulse operation and a transition duty value at which the pulse width gradually increases at the initial stage of the pulse operation,

the duty ratio control unit has a stable duty ratio value in which the pulse width is fixed in a stable stage after the initial stage of the pulse operation,

the duty ratio control section switches from the transition duty ratio value to a steady mode duty ratio value based on a capacitor voltage of the capacitor or a voltage change of the capacitor voltage.

3. The direct current pulse power supply device according to claim 2,

the pulse mode control unit includes a voltage determination unit that determines a state of charge of the capacitor based on a voltage or a voltage change of the capacitor voltage,

the duty control section switches from the transition duty value to a steady mode duty value based on a result determined by the voltage determination section according to a voltage or a voltage change of the capacitor voltage.

4. The direct current pulse power supply apparatus according to any one of claims 1 to 3,

the DC pulse power supply device includes a regeneration unit that regenerates a voltage amount exceeding a set voltage in a reactor voltage of the DC reactor to the DC power supply,

the regeneration unit includes the capacitor connected in parallel to the dc reactor, and the capacitor uses a reactor voltage of the dc reactor as a regeneration input voltage.

5. A duty ratio control method of a direct current pulse power supply device,

the DC pulse power supply device includes:

a direct current power supply;

a pulse unit connected to the dc power supply and generating a pulse output by a boost chopper circuit including a series circuit of a dc reactor and a switching element;

a pulse unit connected to the dc power supply and generating a pulse output by a boost chopper circuit including a series circuit of a dc reactor and a switching element;

a voltage clamp unit including a capacitor connected in parallel to the dc reactor of the pulse unit, the voltage clamp unit limiting a voltage across the dc reactor to a clamp voltage by a capacitor voltage of the capacitor; and

a control circuit unit for controlling the switching operation of the switching element of the pulse unit,

it is characterized in that the preparation method is characterized in that,

the control circuit unit performs duty control for changing a pulse width of the switching element to close the switching element to set the dc reactor in an energized state, in a pulse mode control for controlling a pulse operation in a pulse mode for generating a pulse output with a constant period,

the duty control is to gradually increase the pulse width from an initial value at the start of the pulse operation in an initial stage of the pulse operation,

the duty control maintains the pulse width at a predetermined fixed width in a stable phase of the pulse operation after the initial phase.

6. The duty ratio control method of the direct current pulse power supply device according to claim 5,

the control circuit unit switches from the initial stage to a steady stage based on the capacitor voltage of the capacitor being charged to a predetermined voltage.

7. The duty ratio control method of the direct current pulse power supply device according to claim 5,

the control circuit unit switches from the initial stage to a steady stage based on the fact that the voltage change of the capacitor voltage of the capacitor converges within a predetermined fluctuation range.

8. The duty ratio control method of the direct current pulse power supply device according to claim 6,

the predetermined voltage is a reset voltage for resetting magnetic saturation of the dc reactor.

Technical Field

The present invention relates to a dc pulse power supply device having a control circuit for suppressing magnetic saturation, and a control method for suppressing magnetic saturation of a dc reactor included in the dc pulse power supply device.

Background

In a dc pulse power supply device, a circuit configuration including a series circuit of a dc reactor and a switching element is known as a pulse generating circuit for generating a pulse output. The pulse generating circuit generates a pulse output having a pulse waveform by repeating on/off operations of the switching element to interrupt the dc voltage.

The pulse output from the dc pulse power supply device is a high-frequency output in which the on state and the off state of a dc voltage are repeated at several Hz (hertz) to several hundreds kHz (kilohertz).

A dc pulse power supply device is used as a power supply device for supplying a pulse output to a load such as a plasma generator, a pulse laser excitation, and an electric discharge machine. For example, when a dc pulse power supply device is used in a plasma generation device, a pulse output is supplied between electrodes in a plasma generation chamber, and plasma is ignited by discharge between the electrodes to sustain the generated plasma.

Fig. 11 shows an example of a configuration of a dc pulse power supply device, and the example of the configuration shown includes a pulse generating circuit using a chopper circuit. In a dc pulse power supply device, a boost chopper circuit is known as a circuit for generating a pulse waveform. The dc pulse power supply device 100 includes a dc power supply unit 110, a pulse unit 120, and a control circuit unit 140. The boost chopper circuit of the pulse unit 120 is configured by a series connection of a dc reactor 121 and a switching element 122, and the switching element 122 performs an on/off operation in accordance with a drive signal of a drive circuit 123 controlled by a control circuit unit 140, and outputs a pulse output to a load 150, the pulse output being obtained by boosting the dc voltage of the dc power supply unit 110 (patent documents 1 and 2).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 8-222258 (FIG. 1, paragraph 0012)

Patent document 2: japanese patent laid-open No. 2006-6053 (FIG. 1)

Disclosure of Invention

Problems to be solved by the invention

When a dc pulse power supply device is used in a plasma generator, a pulse output from the dc pulse power supply device is supplied between electrodes in a chamber of the plasma generator, and a discharge generated between the electrodes ignites a plasma to sustain the generated plasma. When a plasma is used as a load, the dc pulse power supply device supplies a pulse output to the plasma load in each of an ignition mode, a dc mode, and a pulse mode. Plasma is ignited in an ignition mode, and after a constant discharge voltage state is passed in a direct current mode, a pulse operation is started in a pulse mode.

Fig. 12 is a schematic flowchart for explaining each mode of supplying a pulse output from the dc pulse power supply device to the plasma load.

In general, a plasma generator corresponds to an electric load for a dc pulse power supply device, and the load at the start of plasma discharge until plasma discharge is generated has a different impedance state from the load during normal operation in which plasma discharge is stably generated. Therefore, in general, the dc power supply device gradually increases the voltage to generate plasma discharge, and applies a voltage larger than the voltage during normal operation to the electrode for a constant period. This output mode is referred to as an ignition mode (S10).

In the ignition mode, a constant discharge voltage state is obtained after the plasma discharge is generated. This output mode is referred to as a direct current mode (S20).

After the dc mode, the dc voltage is turned on/off at a predetermined duty ratio to be in a pulse output state. This output pattern is referred to as a pulse pattern (S30).

In the chopper circuit of the pulse section 120A shown in fig. 13 (a), a DS voltage between the drain D and the source S of the switching element 122A generates a surge voltage due to a leakage inductance included in the dc reactor 121A when the switching element 122A is turned off. In order to avoid damage to the switching element 122A due to a surge voltage, the inventors of the present application have proposed a configuration in which a voltage clamp section 130B is provided, and the voltage clamp section 130B clamps a voltage across the dc reactor 121B to a predetermined voltage. Fig. 13 (b) shows an outline of the proposed circuit configuration. The voltage clamp 130B includes a capacitor C connected in parallel to the dc reactor 121B. The voltage clamp section 130B clamps the voltage VC of the capacitor C to a voltage lower than the surge voltage, thereby suppressing an excessive surge voltage rise of the DS voltage.

Generally, when the magnetic field of the reactor increases with an increase in the reactor current, the magnetic permeability of the reactor decreases, and the reactor becomes magnetically saturated when the reactor reaches the maximum magnetic flux density of the magnetic material. The magnetic permeability is reduced in the state of magnetic saturation. The low magnetic permeability of the reactor becomes a factor of the excessive current. By applying voltages of different polarities to the reactor, the voltage-time product (ET product), which is the product of the applied voltage and time, is made to be of opposite polarity and equal in magnitude, thereby resetting the reactor from magnetic saturation.

In fig. 13 (c), the voltage-time product Son during the on period and the voltage-time product Soff during the off period of the switching element 122B are made to have opposite polarities and equal magnitudes, so that the magnetic saturation of the dc reactor 121B is reset.

Fig. 14 is a diagram for explaining the magnetic saturation state of the dc reactor, where fig. 14 (a) shows an output voltage waveform of the dc power supply device, fig. 14 (b) shows a saturation current waveform of the dc reactor current iDCL, and fig. 14 (C) shows a voltage waveform of the capacitor C.

In a circuit configuration including a voltage clamp portion, there is a problem that magnetic saturation reset of a dc reactor is insufficient. Fig. 13 (c) shows a state where magnetic saturation occurs. The voltage Voff of the off period Toff of the switching element 122B functions as a reset voltage, and the voltage Voff gradually rises from 0V at the start of pulse generation, and is clamped by the capacitor voltage VC of the capacitor C of the voltage clamping section 130B, so that the reset voltage does not rise to a voltage sufficient to reset magnetic saturation in the initial stage. Therefore, in the initial pulse mode at the time of pulse generation start, the voltage-time product Soff during the off period of the switching element 122B is smaller than the voltage-time product Son during the on period Ton of the switching element 122B, and the bias of the dc reactor is not reset and reaches magnetic saturation.

When the dc reactor 121 is magnetically saturated, the inductance decreases, and thus an excessive current flows. Fig. 15 shows an example of a current of the dc reactor, and shows a state where an excessive current is generated due to magnetic saturation. Therefore, in the initial pulse mode at the time of pulse generation start, there is a problem that an excessive current is generated due to magnetic saturation because a reset voltage for resetting the magnetic saturation is insufficient.

The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to suppress magnetic saturation of a dc reactor at the time of pulse generation start and to suppress generation of an excessive current due to the magnetic saturation in a dc pulse power supply device.

More specifically, the object is to suppress magnetic saturation by suppressing a dc reactor current during a period from a capacitor voltage of a capacitor connected in parallel with the dc reactor to a voltage sufficient for magnetic saturation reset at the time of pulse generation start.

Means for solving the problems

A DC pulse power supply device of the present invention includes a voltage clamp section including a capacitor connected in parallel to a DC reactor in order to suppress an increase in surge voltage due to leakage inductance of the DC reactor of a chopper circuit provided in a pulse section. In a dc pulse power supply device, a reactor voltage when a switching element of a chopper circuit is in an off state is suppressed by a voltage clamp portion, which becomes a factor of magnetic saturation of a dc reactor. A control circuit unit of a DC pulse power supply device resets magnetic saturation of a DC reactor by controlling a duty ratio of an operation of a switching element, thereby suppressing generation of magnetic saturation.

In a DC pulse power supply device, at the start of a pulse operation which is an initial stage of a pulse mode, a duty ratio of the pulse operation of a chopper circuit is controlled until a capacitor voltage is charged to a voltage sufficient to reset magnetic saturation of a DC reactor, and a pulse width for turning a switching element into an ON state and turning the DC reactor into an ON state is changed. By gradually increasing the duty ratio or the pulse width, the increase of the voltage-time product in which the switching element is in the on state is gradually increased. By gradually increasing the duty ratio and the pulse width, even when the clamp voltage is suppressed by the off operation of the switching element, it is possible to suppress an increase in the difference between the voltage-time product of the on state of the switching element and the voltage-time product of the off state of the switching element, thereby suppressing magnetic saturation of the dc reactor.

Here, gradually increasing means gradually increasing from an initial value to a predetermined value. The predetermined value that is reached by the gradual increase in the duty ratio or the pulse width is the duty ratio or the pulse width at which the capacitor voltage becomes a voltage sufficient to reset the magnetic saturation of the dc reactor by the on state of the switching element. The initial value is a value at which the reactor is not magnetically saturated, and is set to a value sufficiently smaller than a predetermined value.

After the pulse operation is started, the capacitor voltage increases in the initial stage to become a stable stage. In the stabilization phase, the voltage applied to the dc reactor is suppressed to the clamp voltage of the capacitor voltage, but by setting the capacitor voltage to a voltage sufficient to reset the magnetic saturation of the dc reactor, the magnetic saturation of the dc reactor is suppressed in the pulse mode switched to the duty ratio in the stabilization phase.

The present invention includes various embodiments of a dc pulse power supply device and a duty ratio control method for the dc pulse power supply device.

[ DC pulse Power supply device ]

The DC pulse power supply device of the present invention includes: a direct current power supply; a pulse unit connected to a dc power supply and generating a pulse output by a boost chopper circuit including a series circuit of a dc reactor and a switching element; a voltage clamp unit including a capacitor connected in parallel to the DC reactor of the pulse unit, the voltage clamp unit limiting a voltage across the DC reactor to a clamp voltage by a capacitor voltage of the capacitor; and a control circuit unit for controlling the switching operation of the switching element of the pulse unit.

The control circuit unit includes a pulse pattern control unit that controls a pulse operation of a pulse pattern for generating a pulse output at a constant cycle. In the pulse operation based on the pulse mode, the switching element is repeatedly turned on and off at a predetermined duty ratio at a constant cycle, and thereby power corresponding to the duty ratio is supplied from the dc power supply to the load by the pulse output.

The pulse mode control unit of the present invention includes a duty control unit for varying a pulse width, and performs duty control in 2 stages, i.e., an initial stage and a steady stage. The duty ratio control unit gradually increases the pulse width for turning on the switching element at the initial stage of the pulse operation, and gradually increases the period for which the reactor current flows in the dc reactor. In the initial stage, since the voltage of the dc reactor is clamped, the voltage-time product of the off state of the switching element is small. When the pulse operation is repeated while maintaining the pulse width of the switching element in the on state at a stable level, the difference in voltage-time product increases to reach magnetic saturation.

In the duty control according to the present invention, in the initial stage, the pulse width of the duty ratio in the steady stage is gradually increased from the initial value toward the pulse width of the duty ratio in the closed state of the switching element, thereby suppressing the voltage-time product in the initial stage in which the switching element is in the on state, suppressing the increase in the difference between the voltage-time product in the initial stage in which the switching element is in the off state, and suppressing the occurrence of magnetic saturation in the initial stage.

In the steady stage, the switching element is turned on/off at a pulse width of a steady duty ratio in a pulse mode, and steady power is supplied to the load. In the steady-state, the capacitor voltage is a voltage sufficient to reset the magnetic saturation of the dc reactor, and therefore, even in a state where the voltage is clamped by the capacitor voltage, the dc reactor does not magnetically saturate in the pulse mode switched to the steady-state duty ratio.

The duty control of the present invention is a duty control for suppressing magnetic saturation of a dc reactor in an initial stage in order to avoid magnetic saturation of the dc reactor, and is a duty control in a stable stage after a capacitor voltage is charged to a voltage sufficient to reset the magnetic saturation.

The duty ratio control of the present invention controls the duty ratio by setting the frequency of the pulse operation to a constant frequency. In the pulse operation with a constant frequency, since the time width of one cycle of the pulse operation is constant, varying the duty ratio corresponds to varying the pulse width. Therefore, by gradually increasing the duty ratio in the duty ratio control of the present invention, the dc reactor is prevented from being magnetically saturated at an initial stage before the capacitor voltage reaches a voltage sufficient to reset the magnetic saturation.

In the initial stage of the pulse operation, the capacitor voltage is not charged to the reset voltage for resetting the magnetic saturation of the dc reactor, and therefore it is difficult to reset the magnetic saturation of the dc reactor by the capacitor voltage.

In the initial stage of the start pulse operation, the duty ratio of the pulse operation of the chopper circuit is controlled to turn the switching element into an on state until the capacitor voltage is charged to a voltage sufficient to reset the magnetic saturation of the DC reactor, and the pulse width of the DC reactor current flowing through the DC reactor is gradually increased. The dc reactor is in an energized state in both the on state and the off state of the switching element, but a dc reactor current flowing through the dc reactor in the on state is larger than a current flowing through the dc reactor in the off state. Thus, during a period corresponding to the pulse width, the current increases in the dc reactor and the dc reactor current flows, thereby promoting the charging of the capacitor. The present invention suppresses generation of magnetic saturation in an initial stage and increases a capacitor voltage by gradually increasing a pulse width from an initial value toward a predetermined value.

The duty control unit of the present invention includes, in a pulse mode, duty values such as a start duty value in an initial stage, a transition duty value in which the duty ratio is gradually increased, and a steady duty value in a steady stage, and performs a pulse operation in each cycle based on the duty values.

At the start of the pulse operation, the pulse operation is started by a duty ratio or a pulse width based on the start duty value. After the pulse action is started, switching is made from the start duty value to the transition duty value, and the pulse action is performed by a duty ratio or a pulse width based on the gradually increasing transition duty value. After the capacitor voltage becomes a voltage sufficient to reset the magnetic saturation, switching from the transition duty cycle value to the stable duty cycle value of the pulse mode. Whether the capacitor voltage reaches a voltage sufficient to reset the magnetic saturation can be detected based on a voltage value or a voltage change of the capacitor voltage of the capacitor. The transition duty cycle value is gradually increased by increasing the duty cycle at each cycle. The increase width of the duty ratio can be set according to the driving condition such as the number of cycles from the start duty ratio value to the steady duty ratio value.

The pulse mode control unit includes a voltage determination unit that determines whether or not the capacitor voltage reaches a charging voltage. The duty control section switches from the transition duty value to the stable duty value of the pulse mode based on a result determined by the voltage determination section according to the voltage value or the voltage change of the capacitor voltage. The voltage of the capacitor voltage is compared with a set voltage, when the capacitor voltage exceeds the set voltage, or when the voltage change Delta VC of the capacitor voltage is compared with a set value, and when the voltage change Delta VC is within the set value, the charging of the capacitor is judged to be completed, and the capacitor voltage reaches a voltage which is enough to reset the magnetic saturation of the direct current reactor. As the set voltage, for example, a preset charge completion voltage can be used.

The direct current pulse power supply device of the present invention includes a regeneration unit for regenerating a voltage amount exceeding a set voltage in a reactor voltage of a direct current reactor to a direct current power supply, the regeneration unit having a configuration including a capacitor connected in parallel to the direct current reactor, the capacitor functioning as a voltage clamp unit for applying a clamp voltage for suppressing a surge voltage to the direct current reactor, and a regeneration unit for regenerating a reset voltage.

[ Duty ratio control method of DC pulse Power supply device ]

A duty ratio control method according to the present invention is a method for controlling a dc pulse power supply device including: a direct current power supply; a pulse unit connected to a dc power supply and generating a pulse output by a boost chopper circuit including a series circuit of a dc reactor and a switching element; a voltage clamp unit including a capacitor connected in parallel to the DC reactor of the pulse unit, the voltage clamp unit limiting a voltage across the DC reactor to a clamp voltage by a capacitor voltage of the capacitor; and a control circuit unit that controls a switching operation of the switching element of the pulse unit, and resets the magnetic saturation of the dc reactor by controlling a duty ratio of the switching operation until the capacitor voltage reaches a voltage sufficient to reset the magnetic saturation of the dc reactor.

The control circuit unit controls a pulse mode control unit that controls a pulse operation of a pulse mode for generating a pulse output of a constant period, controls a time period for which the switching element is turned on/off, and performs duty control capable of changing a pulse width in a section in which the dc reactor current increases.

In the duty-cycle control,

(a) in the initial stage of the pulse operation, the pulse width is gradually increased from the initial value at the start of the pulse operation to the steady value in the steady stage.

(b) In a stable stage of the pulse operation after the initial stage, the pulse width is maintained at a stable value of a predetermined fixed width.

In the initial stage of the pulse operation, the capacitor voltage is charged while the pulse width is gradually increased from the initial value to the steady value, and after the capacitor voltage is sufficiently charged, the increase of the capacitor voltage is stopped and the capacitor voltage becomes a constant voltage. By setting the capacitor voltage at this time to a voltage sufficient to reset the magnetic saturation of the dc reactor, the magnetic saturation of the dc reactor can be reset.

The present invention sets the capacitor voltage at this time to a predetermined voltage. The predetermined voltage is a capacitor voltage sufficient to stably reset the magnetic saturation of the capacitor in the pulse mode, and is a voltage for determining a switching timing to a stable duty ratio. Whether or not the capacitor voltage reaches the predetermined voltage can be detected based on the voltage value or the voltage change of the capacitor voltage, and it can be determined that the capacitor voltage reaches the predetermined voltage by detecting that the voltage value of the capacitor voltage reaches the predetermined voltage value or the voltage change of the capacitor voltage is stopped. The predetermined voltage value can be determined by obtaining a voltage value of a capacitor voltage when the capacitor is charged to a voltage sufficient to reset magnetic saturation in advance.

After the capacitor voltage is charged to a predetermined voltage, the power supply limitation by the duty control is released, and the pulse width is maintained at a stable value of a predetermined width to supply a predetermined power to the load. In the case of plasma as a load, a pulse output is formed by a pulse width of a predetermined duty ratio based on a pulse pattern, and the pulse output is supplied to the plasma load to maintain plasma discharge.

Effects of the invention

As described above, according to the present invention, in the dc pulse power supply device, it is possible to suppress magnetic saturation of the dc reactor due to the pulse operation and to suppress generation of an excessive current due to the magnetic saturation.

In the pulse operation of the dc pulse power supply device, the power supply to the load is limited by controlling the duty ratio at the initial stage of the period until the capacitor voltage of the capacitor connected in parallel with the dc reactor reaches a voltage sufficient to reset the magnetic saturation, thereby suppressing the magnetic saturation, and the power supply by the duty ratio control is stopped at the stable stage when the capacitor voltage reaches a voltage sufficient to reset the magnetic saturation, and the power supply is performed according to the stable duty ratio value of the pulse mode.

Drawings

Fig. 1 is a flowchart illustrating duty control of a dc pulse power supply device according to the present invention.

Fig. 2 is a waveform diagram for explaining the voltage and current states by duty control of the dc pulse power supply device according to the present invention.

Fig. 3 is a current waveform diagram of the dc reactor current at the time of duty control according to the present invention.

Fig. 4 is a schematic configuration of the magnetic saturation reset unit according to the present invention.

Fig. 5 is a diagram for explaining a first configuration example of the dc pulse power supply of the present invention.

Fig. 6 is a diagram for explaining an example of a circuit configuration of an inverter circuit provided in a regeneration unit of a dc pulse power supply device according to the present invention.

Fig. 7 is a diagram for explaining a second configuration example of the dc pulse power supply of the present invention.

Fig. 8 is a diagram for explaining a third configuration example of the dc pulse power supply of the present invention.

Fig. 9 is a diagram for explaining a fourth configuration example of the dc pulse power supply of the present invention.

Fig. 10 is a diagram for explaining a fifth configuration example of the dc pulse power supply of the present invention.

Fig. 11 is a diagram for explaining a configuration example of a conventional dc pulse power supply device.

Fig. 12 is a schematic flowchart for explaining each mode of supplying a pulse output from the dc pulse power supply device to the plasma load.

Fig. 13 is a diagram for explaining magnetic saturation of the dc reactor.

Fig. 14 is a diagram for explaining a magnetic saturation state of the dc reactor.

Fig. 15 is a diagram for explaining an example of the current of the dc reactor.

Detailed Description

The pulse unit provided in the dc pulse power supply device of the present invention includes a chopper circuit for generating a pulse output from a dc voltage, and a voltage clamp unit including a capacitor connected in parallel to a dc reactor of the chopper circuit in order to suppress an increase in surge voltage due to leakage inductance of the dc reactor of the chopper circuit. The voltage clamp unit clamps the voltage across the DC reactor to a capacitor voltage to suppress the rise of the surge voltage.

On the other hand, in the dc pulse power supply device, since the reactor voltage when the switching element of the chopper circuit is in the off state is suppressed by the voltage clamp portion, the voltage time product for resetting the magnetic saturation becomes insufficient, which becomes a factor of the magnetic saturation of the dc reactor.

A control circuit unit of a DC pulse power supply device controls the duty ratio of the operation of a switching element so that the voltage-time product of the switching element in an off state becomes an amount sufficient for performing magnetic saturation reset, thereby suppressing the occurrence of magnetic saturation due to the clamped reset voltage.

In a DC pulse power supply device, at the start of a pulse operation which is an initial stage of a pulse mode, a duty ratio or a pulse width of a pulse operation of a chopper circuit is controlled so that a switching element is in an ON state and a pulse width of a DC reactor current larger than an OFF state is made variable until a capacitor voltage is charged to a voltage sufficient to reset magnetic saturation of a DC reactor. By gradually increasing the duty ratio or the pulse width, the increase of the voltage-time product in which the switching element is in the on state is gradually increased.

By gradually increasing the duty ratio and the pulse width, even when the clamp voltage is suppressed by the off operation of the switching element, by relatively increasing the time width in the off state, it is possible to suppress magnetic saturation of the dc reactor caused by the voltage-time product in the off state of the switching element being smaller than the voltage-time product in the on state of the switching element.

Here, gradually increasing means gradually increasing from an initial value toward a predetermined value. The steady value obtained by the gradual increase is a duty ratio or a pulse width when the capacitor voltage becomes a voltage sufficient to reset the magnetic saturation of the dc reactor by the on state of the switching element. The initial value is a value sufficiently smaller than the steady value.

In the pulse mode, the pulse operation includes an initial stage at the time of start and a stable stage after the start, and the capacitor voltage increases in the initial stage and shifts to the stable stage after the capacitor voltage reaches a voltage sufficient for reset. In this stabilization phase, the clamp voltage based on the capacitor voltage becomes a voltage sufficient to reset the magnetic saturation of the dc reactor. In this stabilization phase, the voltage applied to the dc reactor is suppressed to the clamp voltage of the capacitor voltage, but the capacitor voltage is a voltage sufficient to reset the magnetic saturation of the dc reactor, and therefore the dc reactor does not magnetically saturate in the pulse mode switched to the stable duty ratio in the stabilization phase.

Duty control of the dc pulse power supply device of the present invention will be described with reference to fig. 1 to 3, and a schematic configuration of the dc pulse power supply device of the present invention will be described with reference to fig. 4. A configuration example of the dc pulse power supply of the present invention will be described with reference to fig. 5 to 10.

[ duty ratio control ]

Fig. 1 is a flowchart for explaining duty control of the dc pulse power supply device of the present invention, and shows duty control in the pulse mode. Fig. 2 shows waveforms of an output voltage (fig. 2 (a)), a dc reactor current (fig. 2 (b)), and a capacitor voltage (fig. 2 (c)) by duty control. Fig. 2 (d) shows a state where magnetic saturation is suppressed in the initial stage of the pulse mode.

When a plasma is used as a load, the dc pulse power supply device supplies power to the plasma load by a pulse operation in each of an ignition mode, a dc mode, and a pulse mode. The pulse operation is to first ignite plasma in an ignition mode, and after a constant discharge voltage state is passed in a direct current mode, to transmit a pulse output generated in the pulse mode to a load. In the pulse mode, a pulse output generated by turning on/off a dc voltage at a predetermined duty ratio is supplied to a plasma load, and plasma discharge is maintained.

In fig. 2, the ignition mode is represented by the IG mode, and the DC mode is represented by the DC mode. In the output voltage waveform shown in fig. 2 (a), in the ignition mode, the output voltage linearly increases from the ground level (GND level). After plasma ignition, the ignition mode is switched to a dc mode, and after a dc voltage of a constant voltage is applied to the dc mode, the mode is switched to a pulse mode to generate a pulse output.

The duty control of the present invention generates a pulse output while switching the duty to each of the start duty value (DutyA), the transition duty value (DutyB), and the stable duty value (DutyPU) of the pulse mode in the pulse mode.

The duty cycle control of the present invention controls the pulse pattern in 2 phases of the initial phase and the stable phase. The initial stage is a period during which the capacitor voltage VC that forms the clamp voltage starts to be charged from 0V and rises to a voltage sufficient to reset magnetic saturation at a stable duty ratio. In this initial stage, the capacitor voltage VC is in a state of being insufficiently charged for the reset of the magnetic saturation of the dc reactor. Therefore, when the dc reactor is driven at a stable duty ratio in a stable state with respect to the duty ratio, the dc reactor becomes magnetically saturated, and an excessive current may be generated. In order to suppress the generation of the magnetic saturation, the duty ratio is gradually increased in the initial stage from the start duty ratio value (DutyA) to the steady duty ratio value (DutyB).

The steady phase is a period during which a steady-state pulse output is generated, and the pulse output is generated from a dc voltage according to the duty ratio of a steady duty ratio value (DutyPU). In this stabilization phase, the capacitor voltage VC is charged to a voltage sufficient to reset the magnetic saturation, and therefore the magnetic saturation of the dc reactor is reset even in a state where the switching element is turned on/off by a stable duty value (DutyPU). Hereinafter, the initial stage and the stable stage of the pulse mode will be described.

[ initial stage of pulse mode ]

The initial phase of the pulse mode enters the transition period from the beginning and then transitions to the stabilization phase.

(initiation of pulse mode)

At the start of the pulse mode, the dc reactor current iDCL is zero (b) of fig. 2), and the capacitor voltage VC is at the ground voltage level (GND ((c) of fig. 2). The capacitor voltage VC is used as a voltage for resetting the magnetic saturation of the dc reactor, but is insufficient to reset the magnetic saturation of the dc reactor since it is at the ground voltage level (GND) at the start of the pulse mode.

When the pulse operation is performed at the stable duty ratio (DutyPU) in the stable phase of the pulse mode from the start of the pulse mode, the on/off operation corresponding to the stable duty ratio (DutyPU) is repeated a plurality of times, and the dc reactor current in a state corresponding to the pulse width flows through the dc reactor.

Since the stable duty value (DutyPU) is set to be able to obtain electric power sufficient to supply electric power necessary for maintaining the plasma state, when the output pulse output is repeated in a state where the magnetic saturation reset voltage is insufficient, the dc reactor reaches magnetic saturation during this time.

In the duty control of the present invention, in the first cycle at the start, the pulse operation is started by the start duty value (DutyA) having a pulse width smaller than that of the steady duty value (DutyPU) (S1). In the first-cycle pulse operation at the start, the dc reactor current iDCL and the capacitor voltage VC increase during the pulse width period in which the switching element is turned on ((b), (c) of fig. 2). Since the capacitor voltage VC increases from 0V, it is insufficient for the reset of magnetic saturation.

(period of transition of duty ratio)

At the beginning of the pulse mode, the capacitor voltage VC is insufficient to reset the magnetic saturation, thus increasing the capacitor voltage VC during the following transition.

After the pulse operation is performed for one cycle at the start of the pulse mode (S2), it is determined whether or not the capacitor voltage VC has reached a voltage sufficient for reset magnetic saturation. This determination can be made by detecting the voltage value of the capacitor voltage VC or the voltage change Δ VC of the capacitor voltage VC. At the stage when the charging of the capacitor voltage VC is completed and reaches a voltage sufficient for reset magnetic saturation, the capacitor voltage VC becomes a constant-voltage charging completion voltage, and the voltage change Δ VC does not change. The charge completion voltage of the capacitor voltage VC is set to a set voltage set corresponding to a voltage sufficient for reset magnetic saturation.

When it is detected that the capacitor voltage VC has reached the set voltage by comparing the capacitor voltage VC with the set voltage, or when it is detected that the voltage change Δ VC has decreased to fall within the set value by comparing the voltage change Δ VC of the capacitor voltage VC with the set value, it is determined that the charging of the capacitor is completed and the capacitor voltage has reached a voltage sufficient to reset the magnetic saturation of the dc reactor. The set voltage and the set value can be a voltage at which the capacitor provided in the voltage clamp unit is charged and a voltage fluctuation range at the time of completion of charging the capacitor.

In the case where the capacitor does not reach the charge completion state, the capacitor voltage VC does not reach the set voltage, or in the case where the voltage variation Δ VC exceeds the set value, during the transition subsequent to the start, the duty ratio is increased by transitioning the duty ratio value (DutyB) instead of the start duty ratio value (DutyA). The transition Duty cycle value (DutyB) during a transition may be determined, for example, by adding Δ Duty to the Duty cycle of the previous cycle. The transition Duty value (DutyB) of the initial period of the transition period may be determined by adding Δ Duty to the start Duty value (DutyA), and from the next period of the transition period, by adding Δ Duty to the last transition Duty value (DutyB). The added amount Δ Duty is a transition width of the Duty ratio, and can be determined by (Duty-Duty a)/N, for example, based on the number N of cycles of the pulse width variation section of the initial stage, the start Duty value (Duty a), and the stable Duty value (Duty pu).

The increase amount of the addition amount Δ Duty is an example, and can be arbitrarily set within the range of the conditions of the cycle number N, the start Duty value (DutyA), and the steady Duty value (DutyPU).

During the transition period of the duty ratio, the capacitor voltage VC increases to the charge completion voltage by the pulse operation of each cycle. On the other hand, the dc reactor current iDCL gradually increases by repeating an increase in a section in which the switching element is in the on state and a decrease in a section in which the switching element is in the off state, but since the voltage-time product in the off state increases due to an increase in the capacitor voltage VC, the magnetic saturation is reset, and therefore the upper limit of the dc reactor current iDCL is limited to the magnetic saturation level or less.

In the last period during the transition of the duty ratio, the capacitor voltage VC is charged to a voltage sufficient to reset the magnetic saturation of the dc reactor. In the step S3, when the state of charge completion of the capacitor voltage VC is detected, the duty ratio is switched from the transition duty ratio value (DutyB) to the stable duty ratio value (DutyPU), and a pulse output is generated by a pulse operation based on the stable duty ratio value (DutyPU) (S5).

Fig. 2 (d) shows a state of the voltage-time product in the initial stage of the pulse mode. In the initial stage of the pulse mode, a voltage corresponding to the on-resistance voltage of the switching element is applied during a period (Ton) in which the switching element is in an on state, and a clamp voltage is applied to the voltage across the dc reactor during a period (Toff) in which the switching element is in an off state. The clamp voltage is a capacitor voltage as a charging voltage of the capacitor, and gradually increases from 0V in an initial stage. In the first period of the initial stage, the voltage-time product Soff during which the switching element is in the off period (Toff) is smaller than the voltage-time product Son during which the switching element is in the on period (Ton), and the dc reactor is in a magnetic bias state.

[ stabilization phase of pulse mode ]

In the stable phase of the pulse mode, the pulse action is performed by the duty ratio of the stable duty ratio value (DutyPU). In this stable stage, the capacitor voltage VC is charged to a voltage sufficient to reset the magnetic saturation of the dc reactor, and therefore the dc reactor is reset without being magnetically saturated, and the dc reactor current iDCL does not exceed the magnetic saturation level although it varies in increase and decrease in each cycle.

Fig. 3 shows the current waveform of the dc reactor current based on the duty cycle control of the present invention. The illustrated current waveform indicates that the dc reactor current does not become an excessive current in any of the initial stage and the steady stage of the ignition mode, the dc mode, and the pulse mode.

[ general Structure of DC pulse Power supply device ]

Fig. 4 shows a configuration example of a dc pulse power supply device according to the present invention. The dc pulse power supply device includes a dc power supply unit 10, a pulse unit 20, a control circuit unit 40, and a voltage detection unit 60, and the pulse unit 20 supplies a pulse output generated from a dc voltage of the dc power supply unit 10 to a load 50.

The pulse unit 20 can be formed of a boost chopper circuit. In fig. 4, the pulse unit 20 includes a boost chopper circuit configured by a series connection of a dc reactor 21 and a switching element 22. The dc reactor 21 is connected in series between the dc power supply unit 10 and the load 50, and the switching element 22 is connected in parallel to the load 50. The drive circuit 23 turns on/off the switching element 22 to convert a dc voltage and generates a pulse output having a pulse waveform. Further, the capacitor C of the voltage clamp 30clamp is connected in parallel to the dc reactor 21.

In the illustrated configuration example, the dc power supply side of the pulse unit 20 includes a terminal B grounded on the high voltage side and a terminal a serving as a negative voltage on the low voltage side. In the figure, the switching element 22 is an example of an FET, and has a source S side connected to a low-voltage side terminal a, a drain D side connected to a high-voltage side terminal B of a ground voltage, and a gate G side to which a drive signal from the drive circuit 23 is input.

The control circuit unit 40 generates a control signal for determining a time width or a duty ratio of the on time and the off time of the switching element 22 corresponding to the target pulse output, and controls the boost chopper circuit via the drive circuit 23. The drive circuit 23 outputs a drive signal to the gate G of the switching element 22 based on the control signal of the control circuit unit 40, and turns on/off the switching element 22.

The source S side of the switching element 22 is connected to the load side of the dc reactor 21, and the drain D side of the switching element 22 is grounded. When the switching element 22 is in the on state, the load side of the dc reactor 21 is grounded, and the dc reactor current iDCL flows from the terminal B to the terminal a via the switching element 22 and the dc reactor 21 in the on state. At this time, electromagnetic energy is accumulated in the dc reactor 21. When the switching element 22 is switched from the on state to the off state, the reactor voltage VDCL is generated in the dc reactor 21 by the energy stored in the dc reactor 21. The boost chopper circuit repeats the on operation and the off operation of the switching element 22, and increases the output voltage Vo in accordance with the duty ratio of the on/off time.

The control circuit unit 40 includes: an ignition mode control unit 42 that ignites plasma in an ignition mode; a dc mode control unit 43 that sets a constant discharge voltage state in a dc mode after plasma ignition; a pulse pattern control unit 44 that forms a pulse output by duty control of a pulse pattern; and a mode switching unit 41 for switching the modes.

The pulse mode control unit 44 changes the pulse width for turning the switching element 22 on by switching the duty value. In the initial stage, a one-cycle pulse action is first performed using the start duty value, and then the duty ratio is gradually increased during a plurality of cycles according to the transition duty value. After the duty ratio is increased in the initial stage, in each period of the subsequent pulse mode, a pulse operation is performed with a stable duty ratio to form a pulse output.

The pulse mode control unit 44 includes a duty control unit 44c for varying a pulse width, and gradually increases the pulse width for closing the switching element at an initial stage of the pulse operation to turn the switching element on, thereby extending a time during which a large dc reactor current flows through the dc reactor. By gradually increasing the pulse width, the difference between the voltage-time product when the switching element is in the on state and the voltage-time product when the switching element is in the off state is suppressed from increasing, and the occurrence of magnetic saturation in the initial stage is suppressed. In the stable phase of the pulse operation, the switching element is closed with a pulse width of a stable duty ratio in a pulse mode, and stable power is supplied to the load. In the steady phase, the capacitor voltage is a voltage sufficient to reset the magnetic saturation of the dc reactor, and therefore, even in a state where the voltage is clamped by the capacitor voltage, the dc reactor does not magnetically saturate in the pulse mode switched to the duty ratio in the steady phase.

The duty controller 44c includes a start duty unit 44c1, a transition duty unit 44c2, and a steady duty unit 44c 3. The start duty unit 44c1 has a start duty value (DutyA), the shift duty unit 44c2 has a shift duty value (DutyB), and the steady duty unit 44c3 has a steady duty value (DutyPU). The pulse mode control unit 44 includes a period detection unit 44a that detects one period, and a voltage determination unit 44b that determines the state of charge of the capacitor using the capacitor voltage VC or the voltage change Δ VC of the capacitor voltage, in addition to the duty control unit 44 c. The capacitor voltage VC is detected by the voltage detection unit 60.

The mode switching unit 41 receives a start signal from the outside and transmits a signal for starting ignition to the ignition mode control unit 42. The ignition mode control unit 42 receives the start signal and performs an ignition operation.

The mode switching unit 41 monitors the output voltage Vo, and outputs a switching signal for switching from the ignition mode to the dc mode control unit 43 based on the output voltage Vo. The dc mode control unit 43 applies a constant dc voltage to set the discharge voltage state.

The mode switching unit 41 transmits a switching signal for switching the dc mode to the pulse mode control unit 44.

In the pulse mode control portion 44, the duty control portion 44c starts the control of the pulse mode using the start duty value (DutyA) of the start duty portion 44c 1. The drive circuit 23 performs on/off operation for one cycle with a pulse width of a start duty value (DutyA).

The cycle detection unit 44a detects each cycle of the pulse operation upon receiving the switching signal of the pulse mode. The cycle detection unit 44a instructs the voltage determination unit 44b to determine the state of charge of the capacitor each time a cycle of the pulse operation is detected. The voltage determination unit 44b determines whether or not the capacitor voltage VC detected by the voltage detection unit 60 reaches the set voltage, or whether or not the voltage change Δ VC, which is the difference between the capacitor voltage VC and the capacitor voltage VC in the previous cycle, is a voltage change larger than the set value, for each cycle of the pulse operation.

In the case where the capacitor voltage VC does not reach the set voltage, or in the case where the voltage change Δ VC exceeds the set value, the duty control portion 44c controls the drive circuit 23 using the transition duty value (DutyB) of the transition duty portion 44c 2. The transition duty unit 44c2 gradually increases the transition duty value (DutyB) for each cycle and updates the value.

The transition Duty ratio portion 44c2 updates the transition Duty ratio value (DutyB) by adding Δ Duty to the last transition Duty ratio value (DutyB). The initial transition duty value (DutyB) uses the start duty value (DutyA) as the last transition duty value.

In the case where the capacitor voltage VC reaches the set voltage, or in the case where the voltage variation Δ VC does not exceed the set value, switching is made from the transition duty value (DutyB) to the stable duty value (DutyPU) of the pulse mode, and the stable duty value (DutyPU) of the stable duty portion 44c3 is used to control the drive circuit 23.

[ example of Structure of DC pulse Power supply device ]

A configuration example of the dc pulse power supply device will be described below. The pulse unit of the direct current pulse power supply device of the configuration example includes a regeneration unit that regenerates a reactor voltage of the direct current reactor. The regeneration unit is provided with a capacitor connected in parallel with the dc reactor, and is configured to regenerate the reactor voltage of the dc reactor.

The first structural example is a structure for regenerating reactor voltages at both ends of a dc reactor of a boost chopper circuit, the second to fifth structural examples are structures for regenerating a reactor voltage of one of two magnetically coupled dc reactors of the boost chopper circuit, the second and fifth structural examples are structures in which two magnetically coupled dc reactors are a tapped single-turn transformer, and the third and fourth structural examples are structures in which two magnetically coupled dc reactors are a multi-turn transformer.

In the first to fifth configuration examples, the voltage on the low voltage side of the dc power supply is used as the reference voltage for the regenerated reactor voltage.

[ first configuration example of DC pulse Power supply device ]

A first configuration example of the dc pulse power supply device of the present invention will be described with reference to fig. 5.

The DC pulse power supply device of the present invention includes: a direct-current power supply unit (DC unit) 10; a pulse unit 20A that supplies a pulse output generated by a boost chopper circuit connected to the dc power supply unit 10 to the load 5; a regeneration unit 30 that regenerates the excessive voltage increase amount generated by the pulse unit 20A to the dc power supply unit 10 side; a control circuit unit 40 for controlling the dc power supply unit 10, the pulse unit 20A, the drive circuit 23, and the regeneration unit 30; and a voltage detection unit 60 that detects the capacitor voltage and supplies a pulse output to the load 5 via the output cable 3. In fig. 5, an example of the plasma generation device is shown as the load 5, but the load 5 is not limited to the plasma generation device, and may be used for pulse laser excitation, an electric discharge machine, and the like.

(DC Power supply section)

The DC power supply unit (DC unit) 10 includes: a rectifier 11 that rectifies an ac voltage of the ac power supply 2 into a dc voltage; a snubber circuit 12 that absorbs and suppresses a spike high voltage generated in a transient state during rectification; a single-phase inverter circuit 13 that converts a direct-current voltage into an alternating-current voltage; a single-phase transformer 14 for converting the ac voltage of the single-phase inverter circuit 13 to a predetermined voltage value; a rectifier 15 that rectifies an ac voltage obtained by voltage conversion of the single-phase transformer 14 into a dc voltage; and a capacitor 16(CF) having a voltage between both ends as a dc voltage of the dc power supply unit. One end of the capacitor 16 is grounded, and the other end forms a low voltage of a negative voltage. In the structure shown in fig. 5, an example of a capacitive load of the plasma generation device is shown as the load 5. Here, since one end of the plasma generating apparatus is grounded and a negative voltage is supplied, the dc power supply unit 10 generates a pulse output of a negative voltage.

The single-phase inverter circuit 13 performs a switching operation in accordance with a control signal from the control circuit unit 40, and converts a dc voltage into an ac voltage of a predetermined frequency. The respective circuit elements of the rectifiers 11 and 15, the snubber circuit 12, the single-phase inverter circuit 13, and the single-phase transformer 14 constituting the dc power supply unit 10 may have any conventionally known circuit configuration.

(pulse section)

The pulse unit 20A generates a pulse waveform from the dc voltage by a boost chopper circuit. The boost chopper circuit includes: a dc reactor 21a connected in series between the dc power supply side and the load side; a switching element (Q1)22 connected in parallel with the load side; and a drive circuit 23 for driving the on/off operation of the switching element 22. The dc power supply side of the pulse unit 20A includes a terminal B connected to ground and a terminal a serving as a negative voltage on the low voltage side. The illustrated switching element 22 is an example of an FET, and has a source S side connected to a low voltage side and a drain D side connected to a ground voltage side, and inputs a drive signal from the drive circuit 23 to a gate G side.

The control circuit unit 40 generates a signal for determining the time width or duty ratio of the on time and the off time of the switching element 22 in accordance with the target pulse output in order to operate the boost chopper circuit, and generates a control signal based on the voltage and the current at the output terminal of the dc power supply unit 10.

The drive circuit 23 outputs a drive signal to the gate G of the switching element 22 based on the control signal of the control circuit unit 40, and performs on/off operation of the switching element 22.

The source S side of the switching element 22 is connected to the load side of the dc reactor 21a, and the drain D side of the switching element 22 is grounded. When the switching element 22 is in the on state, the load side of the dc reactor 21a is grounded, a current flows from the terminal B to the terminal a via the switching element 22 and the dc reactor 21a in the on state, and a dc reactor current flows through the dc reactor 21 a. At this time, electromagnetic energy is accumulated in the dc reactor 21a by the dc reactor current. When the switching element 22 is switched from the on state to the off state, the reactor voltage VDCL is generated in the dc reactor 21a by the energy stored in the dc reactor 21 a. The boost chopper circuit repeats the on operation and the off operation of the switching element 22, and increases the output voltage Vo in accordance with the duty ratio of the on/off time.

(regeneration section)

The regeneration unit 30 regenerates, to the dc power supply, a voltage amount exceeding a set voltage within a reactor voltage of a dc reactor of the boost chopper circuit. The regeneration unit 30 includes a diode 31, a capacitor 32(C1), an inverter circuit 33, a transformer 34, and a rectifier 35. The regeneration section 30 constitutes a regeneration function, and also constitutes a function of a voltage clamp section 30 clamp.

One end of the capacitor 32(C1) is connected to the load-side end of the dc reactor 21a, and the other end is connected to the dc power supply-side end of the dc reactor 21a via the diode 31, and a reactor voltage generated in the dc reactor 21a is applied thereto. The capacitor voltage VC1 of the capacitor 32(C1) is determined based on the dc voltage VAB of the dc power supply and the transformation ratio of the transformer, and when the transformation ratio of the transformer 34 is (n 2: n1), VC1 is set to (n2/n1) × VAB. The diode 31 is connected with the direction from the pulse unit 20A toward the capacitor 32(C1) of the regeneration unit 30 as the forward direction, and when the reactor voltage VDCL of the dc reactor 21a exceeds the capacitor voltage VC1 of the capacitor 32(C1), the regeneration unit 30 regenerates the reactor voltage VDCL by a voltage amount exceeding the capacitor voltage VC1 of the capacitor 32 (C1). Therefore, the regeneration unit 30 performs a regeneration operation with the capacitor voltage VC1 of the capacitor 32(C1) as a threshold value.

As a method of determining the capacitor voltage VC1, the output of the inverter circuit 33 may be controlled in addition to changing the transformation ratio of the transformer 34. For example, PWM control, phase shift control, and the like are available, but the present invention is not limited to this as long as the output of the inverter circuit is controlled.

In the circuit configuration shown in fig. 5, the regeneration unit 30 has one end connected to the low-voltage-side input terminal of the pulse unit 20A, and regenerates the reactor voltage VDCL of the dc reactor 21a as the regeneration input voltage Vin with reference to the voltage (negative voltage) on the low voltage side.

The inverter circuit 33 performs dc-ac conversion between the dc voltage on the capacitor 32 side and the ac voltage on the transformer 34 side, maintains the capacitor voltage VC1 of the capacitor 32(C1) at a constant voltage based on the dc voltage VAB of the dc power supply, and converts the excess voltage amount to ac and regenerates it to the dc power supply side when the reactor voltage VDCL exceeds the capacitor voltage VC1 of the capacitor 32 (C1). Since the capacitor voltage VC1 is kept at a constant voltage, the reactor voltage VDCL of the direct current reactor 21a is clamped to the capacitor voltage VC 1. Therefore, the regeneration section 30 functions as a voltage clamp section 30 clamp. The inverter circuit 33 can be formed of, for example, a bridge circuit of switching elements. The switching operation of the switching element is controlled in accordance with a control signal α from the control circuit unit 40.

The transformer 34 modulates a voltage ratio between the dc voltage VAB of the dc power supply unit 10 and the capacitor voltage VC1 of the capacitor 32(C1) based on the transformation ratio. In the case where the transformation ratio of the transformer 34 is (n 2: n1), the voltage relationship between the dc voltage VAB and the capacitor voltage VC1 is represented by VC1 ═ n2/n1 × VAB.

The rectifier 35 rectifies the ac voltage on the transformer 34 side into a dc voltage on the dc power supply unit 10 side. The dc-side terminal of the rectifier 35 is connected to the terminal A, B of the dc power supply unit 10, and power is regenerated to the dc power supply unit 10 only when the capacitor voltage VC1 exceeds the voltage based on the dc voltage VAB.

The voltage detection unit 60 detects a clamp voltage of the dc reactor 21a based on the capacitor voltage VC1, and transmits a detection signal β to the control circuit 40. The voltage determination section 44b in the control circuit 40 determines the charged state of the capacitor from the capacitor voltage VC based on the detection signal β.

The configuration of the regeneration unit 30 is not limited to the above configuration as long as it has a function of clamping the voltage across the dc reactor 21a to a predetermined voltage and a function of regenerating an amount of electric power exceeding the predetermined voltage to the dc power supply side.

(example of the regeneration section)

A circuit configuration example of an inverter circuit provided in a regeneration unit of a dc pulse power supply device will be described with reference to fig. 6.

The regeneration unit 30 includes an inverter circuit 33, and the inverter circuit 33 outputs an ac voltage obtained by dc-ac converting the dc voltage VC1 of the capacitor 32(C1) to the transformer 34. The inverter circuit 33 includes: a bridge circuit 33a including switching elements QR1 to QR 4; and a drive circuit 33b that generates drive signals for driving the switching elements QR1 to QR4 based on the control signal α. Here, an example of a full bridge circuit is shown as the bridge circuit 33a, but a half bridge circuit or a multiphase inverter circuit may be used.

[ second Structure of DC pulse Power supply device ]

A second configuration example of the dc pulse power supply device of the present invention will be described with reference to fig. 7. The second configuration example is different from the first configuration example in the configuration of the boost chopper circuit of the pulse section 20, and the other configurations are the same as the first configuration example. Hereinafter, a configuration different from the first configuration example will be described, and a description of other common configurations will be omitted.

The dc reactor 21a included in the boost chopper circuit of the first configuration example is formed of a single coil. In contrast, the dc reactor 21b of the second configuration example is constituted by a tapped single-turn transformer instead of the single coil of the boost chopper circuit of the first configuration example. The dc reactor 21b, which is formed of a tapped single-turn transformer, may be formed by connecting a magnetically coupled first dc reactor 21b-1 and second dc reactor 21b-2 in series, with the connection point of the first dc reactor 21b-1 and the second dc reactor 21b-2 being a tap point. One end of the first dc reactor 21b-1 is connected to the low-voltage-side terminal a of the dc power supply, one end of the second dc reactor 21b-2 is connected to the load side, and a tap point of a connection point between the first dc reactor 21b-1 and the second dc reactor 21b-2 is connected to the source S terminal of the switching element 22.

When the switching element 22 is in the on state, a tap point of a connection point of the dc reactor 21B is grounded, and a dc reactor current flows from the terminal B to the terminal a via the switching element 22 in the on state and the first dc reactor 21B-1 of the dc reactor 21B. At this time, electromagnetic energy is accumulated in the first dc reactor 21b-1 by the dc reactor.

When the switching element 22 is switched from the on state to the off state, the reactor voltage VDCL1 is generated in the first dc reactor 21b-1 and the reactor voltage VDCL2 is generated in the second dc reactor 21b-2 by the energy stored in the first dc reactor 21b-1 of the dc reactor 21 b. The boost chopper circuit increases the output voltage Vo in the same manner as in the first configuration example by repeating the on operation and the off operation of the switching element 22.

The voltage ratio between the reactor voltage VDCL1 of the first dc reactor 21b-1 and the reactor voltage VDCL2 of the second dc reactor 21b-2 corresponds to the ratio of the inductance ratio between the first dc reactor 21b-1 and the second dc reactor 21 b-2. The turn ratio of the tapped single-turn coil of the first direct-current reactor 21b-1 and the second direct-current reactor 21b-2 of the direct-current reactor 21b is n1 p: in the case of n2p, the voltage ratio (VDCL1/VDCL2) between the reactor voltage VDCL1 of the first dc reactor 21b-1 and the reactor voltage VDCL2 of the second dc reactor 21b-2 is the turn ratio (n1p/n2 p).

The regeneration unit 30 of the second configuration example operates in the same manner by applying the reactor voltage VDCL1 of the first dc reactor 21b-1 of the dc reactor 21b instead of the reactor voltage VDCL of the dc reactor 21a of the first configuration example.

In the regeneration unit 30, one end of the capacitor 32(C1) is connected to a connection point between the first dc reactor 21b-1 and the second dc reactor 21b-2 of the dc reactor 21b, and the other end is connected to a dc power supply side end of the first dc reactor 21b-1 via the diode 31, and the reactor voltage VDCL1 generated in the first dc reactor 21b-1 is applied. The capacitor voltage VC1 of the capacitor 32(C1) is determined based on the dc voltage VAB of the dc power supply and the transformation ratio of the transformer 34, and when the transformation ratio of the transformer 34 is (n 2: n1), VC1 is set to (n2/n1) × VAB. When the reactor voltage VDCL1 of the first dc reactor 21B-1 exceeds the capacitor voltage VC1 of the capacitor 32(C1), the regeneration unit 30 regenerates the reactor voltage VDCL1 by the amount of voltage exceeding the capacitor voltage VC1 of the capacitor 32(C1) by connecting the diode 31 with the direction from the pulse unit 20B toward the capacitor 32(C1) of the regeneration unit 30 as the forward direction. Therefore, as in the first configuration example, the regeneration unit 30 performs a regeneration operation with the capacitor voltage VC1 of the capacitor 32(C1) as a threshold value.

As in the first configuration example, the regeneration unit 30 constitutes a voltage clamp unit that clamps the voltage across the first dc reactor 21 b-1. The voltage detector 60 detects a clamp voltage of the first dc reactor 21b-1 based on the capacitor voltage VC1, and sends a detection signal β to the control circuit 40. The voltage determination section 44b in the control circuit 40 determines the charged state of the capacitor from the capacitor voltage VC based on the detection signal β.

The output voltage Vo is obtained by superimposing the reactor voltage VDCL1 of the first dc reactor 21b-1 and the reactor voltage VDCL2 of the second dc reactor 21b-2 on the dc voltage VAB of the dc power supply (Vo VAB + VDCL1+ VDCL 2). Since the reactor voltage VDCL1 of the first dc reactor 21b-1 is clamped to the capacitor voltage VC1, the output voltage Vo becomes Vo VAB + VC1+ VDCL 2.

[ third Structure of DC pulse Power supply device ]

A third configuration example of the dc pulse power supply device of the present invention will be described with reference to fig. 8. The third configuration example is different from the first and second configuration examples in the configuration of the boost chopper circuit of the pulse section 20C, and the other configurations are the same as the first and second configuration examples. Hereinafter, a configuration different from the first and second configuration examples will be described, and a description of other common configurations will be omitted.

The dc reactor 21b included in the boost chopper circuit of the second configuration example is formed of a tapped single-turn transformer. In contrast, the dc reactor 21c of the third configuration example is configured by a multi-turn transformer instead of the tapped single-turn transformer of the boost chopper circuit of the second configuration example. An example of a polarity-adding transformer is shown as a multi-turn transformer of the dc reactor 21 c.

The dc reactor 21c formed of a multi-turn transformer is configured by connecting a first dc reactor 21c-1 and a second dc reactor 21c-2, which are magnetically coupled, in parallel. The first dc reactor 21c-1 has one end connected to the terminal a on the low voltage side of the dc power supply and the other end connected to the source S of the switching element 22. One end of the second dc reactor 21c-2 is connected to the source S end of the switching element 22, and the other end is connected to the load side.

When the switching element 22 is in the on state, the end of the dc reactor 21c on the switching element 22 side of the first dc reactor 21c-1 is grounded, and a dc reactor current flows from the terminal B to the terminal a via the switching element 22 and the first dc reactor 21c in the on state. At this time, electromagnetic energy is accumulated in the first dc reactor 21c by the dc reactor.

Next, when the switching element 22 is switched from the on state to the off state, the reactor voltage VDCL1 is generated in the first dc reactor 21c-1 by the accumulated energy accumulated in the first dc reactor 21c-1 of the dc reactor 21c, and the reactor voltage VDCL2 is generated in the second dc reactor 21c-2 by magnetic coupling with the first dc reactor 21 c-1. The boost chopper circuit repeats the on operation and the off operation of the switching element 22, thereby increasing the output voltage Vo in the same manner as in the first and second configuration examples.

The voltage ratio between the reactor voltage VDCL1 of the first dc reactor 21c-1 and the reactor voltage VDCL2 of the second dc reactor 21c-2 corresponds to the ratio of the inductance ratio between the first dc reactor 21c-1 and the second dc reactor 21 c-2. When the turn ratio of the multi-turn coil of the first dc reactor 21c-1 and the second dc reactor 21c-2 of the dc reactor 21c is set to (n1 p: n2p), the voltage ratio (VDCL1/VDCL2) of the reactor voltage VDCL1 of the first dc reactor 21c-1 to the reactor voltage VDCL2 of the second dc reactor 21c-2 becomes the turn ratio (n1p/n2 p).

The regeneration unit of the third configuration example operates in the same manner as the reactor voltage VDCL1 of the first dc reactor 21b-1 of the dc reactor 21b of the second configuration example.

In the regeneration unit 30, one end of the capacitor 32(C1) is connected to the switching element side end of the first dc reactor 21C-1 of the dc reactor 21C, and the other end is connected to the dc power supply side end of the first dc reactor 21C-1 via the diode 31, and the reactor voltage VDCL1 generated in the first dc reactor 21C-1 is applied. The capacitor voltage VC1 of the capacitor 32(C1) is determined based on the dc voltage VAB of the dc power supply and the transformation ratio of the transformer, and when the transformation ratio of the transformer 34 is (n 2: n1), VC1 is set to (n2/n1) × VAB. The diode 31 is connected with the direction from the pulse unit toward the capacitor 32(C1) of the regeneration unit 30 as the forward direction, and when the reactor voltage VDCL1 of the first dc reactor 21C-1 exceeds the capacitor voltage VC1 of the capacitor 32(C1), the regeneration unit 30 regenerates the voltage amount by which the reactor voltage VDCL1 exceeds the capacitor voltage VC1 of the capacitor 32 (C1). Therefore, as in the first and second configuration examples, the regeneration unit 30 performs a regeneration operation with the capacitor voltage VC1 of the capacitor 32(C1) as a threshold value.

In the same manner as in the first configuration example, the regeneration unit 30 constitutes a voltage clamp unit that clamps the voltage across the dc reactor 21 c-1. The voltage detection unit 60 detects a clamp voltage of the dc reactor 21c-1 based on the capacitor voltage VC1, and transmits a detection signal β to the control circuit 40. The voltage determination section 44b in the control circuit 40 determines the charged state of the capacitor from the capacitor voltage VC based on the detection signal β.

The output voltage Vo is obtained by superimposing the reactor voltage VDCL1 of the first dc reactor 21c-1 and the reactor voltage VDCL2 of the second dc reactor 21c-2 on the dc voltage VAB of the dc power supply (Vo VAB + VDCL1+ VDCL 2). Since the reactor voltage VDCL1 of the first dc reactor 21c-1 is clamped to the capacitor voltage VC1, the output voltage Vo becomes Vo VAB + VC1+ VDCL 2. When the turn ratio of the first dc reactor 21c-1 to the second dc reactor 21c-2 is (n1p/n2p), the reactor voltages VDCL1 and VDCL2 are represented by (VDCL1/VDCL2 — n1p/n2 p).

[ fourth Structure of DC pulse Power supply device ]

A fourth configuration example of the dc pulse power supply device of the present invention will be described with reference to fig. 9. The fourth configuration example is different from the third configuration example in the configuration of a transformer for a dc reactor in a boost chopper circuit constituting the pulse section 20D, and the other configuration is the same as the third configuration example.

The dc reactor 21c included in the boost chopper circuit of the third configuration example is a multi-turn transformer with a polarity added. In contrast, the dc reactor 21d of the fourth configuration example is configured by a multi-turn transformer of a decreasing polarity instead of the multi-turn transformer of an increasing polarity of the boost chopper circuit of the third configuration example.

The dc reactor 21d formed of a multi-turn transformer is configured by connecting a magnetically coupled first dc reactor 21d-1 and second dc reactor 21d-2 in parallel. The first dc reactor 21d-1 has one end connected to the terminal a on the low voltage side of the dc power supply and the other end connected to the source S of the switching element 22. One end of the second dc reactor 21d-2 is connected to the terminal a on the low voltage side of the dc power supply, and the other end is connected to the load side.

When the switching element 22 is in the on state, the end of the dc reactor 21d on the switching element 22 side of the first dc reactor 21d-1 is grounded, and a dc reactor current flows from the terminal B to the terminal a via the switching element 22 and the first dc reactor 21d-1 in the on state. At this time, electromagnetic energy is accumulated in the first DC reactor 21d-1 by the DC reactor.

When the switching element 22 is switched from the on state to the off state, the reactor voltage VDCL1 is generated in the first dc reactor 21d-1 by the energy stored in the first dc reactor 21d-1 of the dc reactor 21d, and the reactor voltage VDCL2 is generated in the second dc reactor 21d-2 by magnetic coupling with the first dc reactor 21 d-1. The boost chopper circuit repeats the on operation and the off operation of the switching element 22, thereby increasing the output voltage Vo in the same manner as in the first, second, and third configuration examples.

The voltage ratio of the reactor voltage VDCL1 of the first dc reactor 21d-1 to the reactor voltage VDCL2 of the second dc reactor 21d-2 corresponds to the ratio of the inductance ratio of the first dc reactor 21d-1 to the second dc reactor 21 d-2. When the turn ratio of the multi-turn coil of the first direct current reactor 21d-1 and the second direct current reactor 21d-2 of the direct current reactor 21d is set to (n1 p: n2p), the voltage ratio (VDCL1/VDCL2) of the reactor voltage VDCL1 of the first direct current reactor 21d-1 to the reactor voltage VDCL2 of the second direct current reactor 21d-2 becomes the turn ratio (n1p/n2 p).

The dc reactor 21d of the regeneration unit of the fourth configuration example operates in the same manner as the reactor voltage VDCL1 of the first dc reactor 21c of the third configuration example.

In the regeneration unit 30, one end of the capacitor 32(C1) is connected to the switching element side end of the first dc reactor 21d-1 of the dc reactor 21d, and the other end is connected to the dc power supply side end of the first dc reactor 21d-1 via the diode 31, and the reactor voltage VDCL1 generated in the first dc reactor 21d-1 is applied. The capacitor voltage VC1 of the capacitor 32(C1) is determined based on the dc voltage VAB of the dc power supply and the transformation ratio of the transformer, and when the transformation ratio of the transformer 34 is (n 2: n1), VC1 is set to (n2/n1) × VAB. The diode 31 is connected with the direction from the pulse unit toward the capacitor 32(C1) of the regeneration unit 30 as the forward direction, and when the reactor voltage VDCL1 of the first dc reactor 21d-1 exceeds the capacitor voltage VC1 of the capacitor 32(C1), the regeneration unit 30 regenerates the voltage amount by which the reactor voltage VDCL1 exceeds the capacitor voltage VC1 of the capacitor 32 (C1). Therefore, as in the first, second, and third configuration examples, the regeneration unit 30 performs a regeneration operation with the capacitor voltage VC1 of the capacitor 32(C1) as a threshold value.

In the same manner as in the first configuration example, the regeneration unit 30 constitutes a voltage clamp unit that clamps the voltage across the dc reactor 21 d-1. The voltage detection unit 60 detects a clamp voltage of the dc reactor 21d-1 based on the capacitor voltage VC1, and transmits a detection signal β to the control circuit 40. The voltage determination section 44b in the control circuit 40 determines the charged state of the capacitor from the capacitor voltage VC based on the detection signal β.

The output voltage Vo is obtained by superimposing the reactor voltage VDCL2 of the second dc reactor 21d-2 on the dc voltage VAB of the dc power supply (Vo VAB + VDCL 2). When the turn ratio of the first dc reactor 21d-1 to the second dc reactor 21d-2 is (n1p/n2p), the reactor voltages VDCL1 and VDCL2 are represented by (VDCL1/VDCL2 ═ n1p/n2 p). Therefore, with VDCL1 clamped by VC1, the output voltage Vo is represented by Vo VAB + VC1 × (n1p/n2 p).

[ fifth Structure of DC pulse Power supply device ]

A fifth configuration example of the dc pulse power supply device of the present invention will be described with reference to fig. 10. The fifth configuration example is different from the second configuration example in the manner of installing the dc reactors of the boost chopper circuit, and the other configurations are the same as the second configuration example. Hereinafter, a configuration different from the second configuration example will be described, and descriptions of other common configurations will be omitted.

The dc reactor 21e included in the boost chopper circuit of the fifth configuration example is formed of a tapped one-turn transformer, similarly to the dc reactor 21b of the boost chopper circuit of the second configuration example, but differs in the manner of installation on the power supply line. The dc reactor 21b of the second configuration example is connected to a low-voltage-side power supply line of the dc power supply, whereas the dc reactor 21e of the fifth configuration example is connected to a high-voltage-side power supply line of the dc power supply.

The direct current reactor 21e composed of a tapped single-turn transformer is configured by connecting a first direct current reactor 21e-1 and a second direct current reactor 21e-2, which are magnetically coupled, in series, and a connection point of the first direct current reactor 21e-1 and the second direct current reactor 21e-2 is set as a tap point. One end of the first dc reactor 21e-1 is connected to the high-voltage-side terminal B of the dc power supply, one end of the second dc reactor 21e-2 is connected to the load side and grounded, and a tap point of a connection point between the first dc reactor 21e-1 and the second dc reactor 21e-2 is connected to the drain D of the switching element 22.

When the switching element 22 is in the on state, a tap point of a connection point of the dc reactor 21e is grounded via the second dc reactor 21e-2, and a dc reactor current flows from the terminal B to the terminal a via the first dc reactor 21e-1 and the switching element 22 in the on state. At this time, electromagnetic energy is accumulated in the first direct current reactor 21e-1 by the direct current reactor.

When the switching element 22 is switched from the on state to the off state, the reactor voltage VDCL1 is generated in the first dc reactor 21e-1 and the reactor voltage VDCL2 is generated in the second dc reactor 21e-2 by the energy stored in the first dc reactor 21e-1 of the dc reactor 21 e. The boost chopper circuit increases the output voltage Vo in the same manner as in the first configuration example by repeating the on operation and the off operation of the switching element 22.

The voltage ratio between the reactor voltage VDCL1 of the first dc reactor 21e-1 and the reactor voltage VDCL2 of the second dc reactor 21e-2 corresponds to the ratio of the inductance ratio between the first dc reactor 21e-1 and the second dc reactor 21 e-2. The turn ratio of a tapped single-turn coil of a first direct current reactor 21e-1 and a second direct current reactor 21e-2 of a direct current reactor 21 is set as n1 p: in the case of n2p, the voltage ratio (VDCL1/VDCL2) between the reactor voltage VDCL1 of the first dc reactor 21e-1 and the reactor voltage VDCL2 of the second dc reactor 21e-2 is the turn ratio (n1p/n2 p).

The regeneration unit 30 of the fifth configuration example operates in the same manner by applying the reactor voltage VDCL1 of the first dc reactor 21e-1 of the dc reactor 21e instead of the reactor voltage VDCL of the dc reactor 21a of the first configuration example.

In the regeneration unit 30, one end of the capacitor 32(C1) is connected to a connection point between the first dc reactor 21e-1 and the second dc reactor 21e-2 of the dc reactor 21e, and the other end is connected to a dc power supply side end of the first dc reactor 21e-1 via the diode 31, and the reactor voltage VDCL1 generated in the first dc reactor 21e-1 is applied. The capacitor voltage VC1 of the capacitor 32(C1) is determined based on the dc voltage VAB of the dc power supply and the transformation ratio of the transformer, and when the transformation ratio of the transformer 34 is (n 2: n1), VC1 is set to (n2/n1) × VAB. When the reactor voltage VDCL1 of the first dc reactor 21e-1 exceeds the capacitor voltage VC1 of the capacitor 32(C1), the regeneration unit 30 regenerates the reactor voltage VDCL1 by the amount of voltage exceeding the capacitor voltage VC1 of the capacitor 32(C1) by connecting the diode 31 in the reverse direction from the pulse unit 20D toward the capacitor 32(C1) of the regeneration unit 30. Therefore, as in the first configuration example, the regeneration unit 30 performs a regeneration operation with the capacitor voltage VC1 of the capacitor 32(C1) as a threshold value.

In the same manner as in the first configuration example, the regeneration unit 30 constitutes a voltage clamp unit for clamping the voltage across the dc reactor 21 e-1. The voltage detection unit 60 detects a clamp voltage of the dc reactor 21e-1 based on the capacitor voltage VC1, and transmits a detection signal β to the control circuit 40. The voltage determination section 44b in the control circuit 40 determines the state of charge of the capacitor based on the capacitor voltage VC based on the detection signal β

The output voltage Vo is obtained by superimposing the reactor voltage VDCL1 of the first dc reactor 21e-1 and the reactor voltage VDCL2 of the second dc reactor 21e-2 on the dc voltage VAB of the dc power supply (Vo VAB + VDCL1+ VDCL 2). Since the reactor voltage VDCL1 of the first dc reactor 21e-1 is clamped to the capacitor voltage VC1, the output voltage Vo becomes Vo VAB + VC1+ VDCL 2.

In the dc pulse power supply device according to the first to fifth configuration examples, the control circuit unit 40 includes a pulse mode control unit that controls a pulse operation of a pulse mode for generating a pulse output at a constant cycle, and the pulse mode control unit includes a duty ratio control unit for varying a pulse width. The duty ratio control unit gradually increases the pulse width of the direct current reactor current flowing through the direct current reactor by closing the switching element in the initial stage of the pulse operation, thereby suppressing an increase in the difference between the voltage-time product of the switching element in the on state and the voltage-time product of the switching element in the off state, and suppressing the occurrence of magnetic saturation in the initial stage of the pulse mode.

Further, the voltage of the S terminal of the switching element is clamped to a voltage lower than the surge voltage, excessive rise of the voltage applied to the switching element is suppressed, and the magnetic saturation of the dc reactors 21a to 21e is reset by duty control of the pulse mode control unit.

The above description of the embodiment and the modifications is an example of the dc pulse power supply device of the present invention, and the present invention is not limited to the embodiments, and various modifications can be made based on the gist of the present invention, and these modifications should not be excluded from the scope of the present invention.

Application in industry

The dc pulse power supply device of the present invention can be used not only as a power source for supplying electric power to a plasma generation device, but also as a power supply device for supplying a pulse output to a load such as a pulse laser excitation and an electric discharge machine.

Description of the reference numerals

1 DC pulse power supply device

2 AC power supply

3 output cable

5 load

10 DC power supply unit

11 rectifier

12 buffer circuit

13 single-phase inverter circuit

14 single-phase transformer

15 rectifier

16 capacitor

20 pulse part

20A-20D pulse part

21. 21 a-21 e DC reactor

22 switching element

23 drive circuit

30 regeneration part

30clamp voltage clamp

31 diode

32 capacitor

33 inverter circuit

33a bridge circuit

33b drive circuit

34 transformer

35 rectifier

40 control circuit part

41 mode switching part

42 ignition mode control part

43 DC mode control part

44 pulse mode control part

44a period detecting part

44b voltage determination unit

44c duty ratio control part

44c1 start duty part

44c2 transition duty cycle part

44c3 Stable Duty cycle part

44c duty ratio control part

50 load

60 voltage detection part

100 D.C. pulse power supply device

110 DC power supply unit

120 pulse part

121 direct current reactor

122 switching element

123 drive circuit

140 control circuit part

150 load

QR1-QR4 switch element

iDCL DC reactor current

Delta VC voltage variation

Alpha control signal

Beta detecting the signal.