JP2003125586A - Power unit for plasma generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To configure a matching circuit extremely simply by avoiding the problem resulting from the capacitance even in a region of high frequency, high voltage, and large power. SOLUTION: N pieces of insulating transformers 14 are provided, and each input-side winding of them is connected, in parallel with the output side of an inverter 13. Each output-side winding of the n pieces of isolation transformers 14 is connected in series, and a resonance circuit 15, which boosts the shortage of the required boosting ratio to be achieved by the n pieces of isolation transformers 14, is connected to this output-side winding connected in series. A matching element 16, which offsets the amount of reactance of a plasma generator 17, is connected to the output side of the resonance circuit 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma generating power supply device applied to a gas laser oscillator such as a laser beam machine for processing a plate material.

[0002]

2. Description of the Related Art Generally, a plasma generating power supply device used in a carbon dioxide laser oscillator or the like has a structure as shown in FIG. That is, in the conventional plasma generating power supply device 50, the AC power of the AC power supply 51 is converted into the DC power by the rectifying / smoothing circuit 52, and then converted into the high frequency power by the inverter 53, and the obtained high frequency power is boosted by the step-up transformer 54. The voltage is boosted by, and is matched by the matching circuit 56 and applied to the discharge electrode 58 of the plasma generating portion 57.

This type of plasma generating power supply device 50 is
Usually, a high voltage of several kV to several tens of kV and a large electric power of several kW to several tens of kW are handled in a high frequency region of several tens of kHz to several tens of MHz.

[0004]

However, such a conventional device is ideal as a reactance element or the like in the step-up transformer 54 or the matching circuit 56 under the conditions of high frequency, high voltage, and high power as described above. You can't expect the correct behavior. For example, the function of the step-up transformer 54 to boost the voltage in accordance with the winding ratio has a problem that it deviates from an ideal state due to a slight electrostatic capacitance parasitic between the conductors of the coil, resulting in matching. There is a problem that the circuit 56 needs a complicated structure.

An object of the present invention is to eliminate the problems of the above-mentioned conventional ones and to eliminate the problems caused by the electrostatic capacitance even in the high frequency, high voltage and high power regions by not using a step-up transformer. Another object of the present invention is to provide a plasma generating power supply device which can be avoided and whose matching circuit can be constructed extremely simply.

[0006]

SUMMARY OF THE INVENTION The present invention is to solve the above problems. According to the invention of claim 1, the output of an inverter for obtaining high frequency power is boosted by a transformer and further matched by a matching circuit. In a plasma generating power supply device applied to a discharge electrode of a plasma generating unit, n insulating transformers are provided, and each input side winding is connected in parallel to the output side of the inverter, and each output side winding is connected. Circuit for connecting the output side windings of the n insulating transformers connected in series to the output windings of the n insulating transformers, the boosting ratio being insufficient for the required boosting ratio. And a matching element for canceling the reactance component of the plasma generation unit is connected to the output side of the resonance circuit.

According to a second aspect of the present invention, in the plasma generating power supply device in which the output of the inverter for obtaining high frequency power is boosted by the transformer and further matched by the matching circuit and applied to the discharge electrode of the plasma generating section, the inverter is used. It is composed of n inverters in parallel relationship with each other, n insulating transformers are provided, and each input side winding is connected to the output side of each of the n inverters, and each output side winding is provided. Circuit for connecting the output side windings of the n insulating transformers connected in series to the output windings of the n insulating transformers, the boosting ratio being insufficient for the required boosting ratio. Connected to the output side of the resonant circuit,
It is a power source device for plasma generation to which a matching element for canceling the reactance component of the plasma generation unit is connected.

According to a third aspect of the present invention, in the invention according to the first or second aspect, the plasma generating unit is a power generating device for plasma generation which is a gas laser generating unit of a gas laser oscillator.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a plasma generating power supply device according to the present invention.
This plasma generating power supply device 10 includes an AC power supply 11 for supplying AC power, a rectifying / smoothing circuit 12 for converting AC power into DC power, an inverter 13 for converting DC power into high frequency power, and n insulating transformers. 14 (14a, 14
b, ..., 14n), a resonance circuit 15, and a matching element 16, and the output of the matching element 16 is a discharge electrode (plasma generating electrode) 18 of a plasma generating container (plasma generating portion) 17.
Is configured to apply to. Of these, the rectifying / smoothing circuit 12 can also use a chopper regulator or the like, and the chopper regulator may merely stabilize or generate pulsed power. Further, the inverter 13 is usually configured by connecting FETs in a bridge.

The insulation transformer 14 has a function of preventing a ground fault of the inverter 13. Further, since each insulation transformer has a step-up ratio of about 1: 1, the number of windings on the secondary side is small. Therefore, since the parasitic reactance is extremely small, it functions as an ideal transformer even in a high frequency region. N such insulating transformers (14a, 14b, ..., 14n) were prepared, and the respective input side windings were connected in parallel to the output side of the inverter 13 and the respective output side windings were connected in series. In addition, the n insulating transformers 14a, 14b, ...
The resonance circuit 15 is connected to the output side winding of 14n.
Therefore, n insulating transformers 14a, 14b, ..., 1
4n constitutes a step-up circuit having a step-up ratio of 1: n as a whole, and since each one insulating transformer functions as an ideal transformer even in a high frequency region, the n-th whole insulating transformer 14 is also It functions as an ideal transformer even in the high frequency range. That is, n insulation transformers 1
, 14n are capable of boosting voltage while maintaining the characteristics of the ideal transformer of each insulating transformer.

In this way, the n insulating transformers 14a,
Since 14b, ..., 14n constitute a step-up circuit having a step-up ratio of 1: n, the resonance circuit 15 that steps up the voltage by resonance is
It is only necessary to boost the shortage of the boosting ratio by the insulating transformer 14 which is insufficient for the required boosting ratio, whereby the current of the resonant circuit 15 can be reduced and the resonant circuit 15 can be reduced.
Since the current capacity of is small, the resonance circuit 15 can be downsized.

The matching element 16 cancels the reactance component of the plasma generating container 17. That is, the matching element 16 equivalently forms a series circuit of C and R, and cancels out the C component of the plasma generation container 17 that shifts the phase of current and voltage. As a result, the phase difference between current and voltage can be reduced and high efficiency can be maintained.

The plasma generating container 17 is usually a capacitor in terms of electric circuit since the container itself or the surface of the electrode is made of a dielectric material such as glass or ceramic.
Further, plasma has almost pure resistance or constant voltage characteristics.

Next, the operation of the above embodiment will be described. In the plasma generating power supply device 10, like the conventional plasma generating power supply device 50, it is inevitable that the number of turns of the secondary winding will be considerably large.
Instead, the number of turns of the secondary winding is small,
In addition, since n insulating transformers 14 having a winding ratio of the primary winding and the secondary winding of about 1: 1 are used, the reactance parasitic to the transformer is extremely small, and high-frequency, high-voltage, and high-power regions are provided. But it can be treated as an ideal transformer.

Moreover, since n insulating transformers 14 can be used to provide a boosting ratio corresponding to the number, and the shortage is boosted by the resonant circuit 15, the resonant circuit 15 can be made compact, and Since the matching element 16 only needs to cancel the reactance component of the plasma generation container 17, instead of the matching circuit 56 having a complicated structure as in the conventional case,
It can be configured with only a very simple matching element 16.

FIG. 2 is a block diagram showing another embodiment of the plasma generating power supply device according to the present invention. This plasma generating power supply device 20 includes an AC power supply 21, a rectifying / smoothing circuit 22, and n inverters. 23 (23a, 23b,
, 23n), n insulation transformers 24 (24a, 24)
b, ..., 24n), a resonance circuit 25, and a matching element 26, and the output of the matching element 26 is applied to a discharge electrode (plasma generating electrode) 28 of a plasma generating container (plasma generating portion) 27. .

N inverters 23 (23a, 23b,
, 23n) are connected in parallel to the rectifying / smoothing circuit 22 and have n insulating transformers 24 (24a, 24n).
b, ..., 24 n) each input winding has n inverters 2
3 (23a, 23b, ..., 23n) are respectively connected to the output side. Others are the same as those of the plasma generating power supply device 10 of FIG.

[0018]

As described above, according to the present invention, in the power supply device for plasma generation, the output of the inverter for obtaining the high frequency power is boosted by the transformer and further matched by the matching circuit and applied to the discharge electrode of the plasma generation part. Insulating transformers are provided, and the respective input side windings are connected in parallel to the output side of the inverter, and the respective output side windings are connected in series to connect the n insulating transformers in series. A resonance circuit for boosting a shortage in which the step-up ratio by the n insulating transformers is insufficient for the required step-up ratio is connected to the output side winding, and the output side of the resonance circuit is connected to the output side of the plasma generation unit. Since a matching element that cancels out the reactance component is connected, the boost transformer is not used, and problems due to capacitance are avoided even in the high frequency, high voltage, and high power regions. It is collected by an effect which can constitute the matching circuit very simple.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a power supply device for plasma generation.

FIG. 2 is a block diagram showing another embodiment of a plasma generating power supply device.

FIG. 3 is a block diagram showing an example of a conventional one.

[Explanation of symbols]

Power supply for plasma generation 11,21 AC power supply 12,22 Rectification smoothing circuit 13,23 Inverter 14, 24 Isolation transformer 15,25 Resonant circuit 16,26 Matching element 17,27 Plasma generation container (plasma generation part) 18, 28 Discharge electrode (plasma generating electrode)

Claims (3)

[Claims] 1. A plasma generating power supply device for boosting an output of an inverter for obtaining high frequency power by a transformer and further matching with a matching circuit to apply to a discharge electrode of a plasma generating section, wherein n insulating transformers are provided, The input side windings are connected in parallel to the output side of the inverter, the output side windings are connected in series, and the output side windings of the n insulation transformers connected in series are A resonance circuit for boosting a shortage in which the boosting ratio by the n insulating transformers is insufficient for the required boosting ratio is connected, and a matching element for canceling the reactance component of the plasma generating unit is provided on the output side of the resonant circuit. A power supply device for plasma generation, which is connected. 2. A plasma generating power supply device in which the output of an inverter for obtaining high frequency power is boosted by a transformer and further matched by a matching circuit to be applied to a discharge electrode of a plasma generating section, wherein the inverters are in parallel relationship with each other. It is composed of n inverters, n insulating transformers are provided, and each of the input side windings is connected to the output side of the n inverters, and each output side winding is connected in series. A resonance circuit is connected to the output side windings of the n insulation transformers connected in series, and a resonance circuit for boosting a deficiency in which the step-up ratio of the n insulation transformers is insufficient for the required step-up ratio is connected. A power generating device for plasma generation, wherein a matching element for canceling the reactance component of the plasma generating part is connected to the output side of the circuit. 3. The plasma generating power supply device according to claim 1 or 2, wherein the plasma generating unit is a gas laser generating unit of a gas laser oscillator.