JPH05235449A - High-frequency power source for laser oscillator - Google Patents

Abstract

PURPOSE:To reduce the distortion of pulse waveforms in a wide range of pulse frequencies of a laser. CONSTITUTION:The title high-frequency power source for laser oscillator has a DC converter part 3 which converts a DC power into a DC power proportional to an output command of a laser, a high-frequency inverter part 7 which converts a DC power into a specified high-frequency power, and a switching part 5 which is arranged between the DC converter part 3 and the high-frequency inverter part 7 and converts a DC power into a pulse power proportional to a pulse wave output command of the laser.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency power source for a laser oscillator.

[0002]

2. Description of the Related Art A general circuit of a conventional high-frequency power source for a carbon dioxide laser oscillator is as shown in FIG. 3, which is a rectifying section 1, a DC converter section 3, a high-frequency inverter section 7, an output control section 13,
Output transformer T, current sensor SI and current signal generator S
It is composed of G and the like.

The rectifying section 1 rectifies a 200 V commercial three-phase AC current and converts it into a smooth DC voltage E ₁ of about 250 V, and is composed of six diode groups D ₁ and a smoothing capacitor C ₁ assembled in a bridge. ing. DC converter unit 3
Is for converting the DC voltage E ₁ into a pulse or continuous waveform DC voltage E ₂ proportional to the command signal. The FET transistor TR ₁ , the feedback diode D ₂ , the choke coil L,
It consists of a capacitor C ₂ . High frequency inverter 7
DC voltage E ₂ frequency (fc) 100kHz ~ 27mH
Converts to a high frequency voltage E _{3 of} about z.
T-transistors TR _{2 to} TR ₅ , high-frequency drive unit DR
And a high frequency oscillator GR.

The output of the high frequency inverter section 7 is supplied to the discharge section of the laser through the output transformer T, and the current of the discharge section is fed back to the output control section 13 by the current sensor SI and the current signal generating section SG. The output control unit 13
The DC voltage E ₂ of the DC converter unit 3 is controlled by the command signal and the feedback signal.
It is composed of an M amplifier circuit (including a triangular wave oscillator).

[0005]

As described above, the DC converter section 3 is controlled by the output control section 13,
Triangle wave frequency fs of the PWM amplifier circuit of the output control unit 13
Is generally 10 kHz to 100 kHz, and transistor TR ₁
Is switched at this frequency, and the generated pulse group becomes a DC voltage E ₂ having a waveform corresponding to the command signal due to the feedback diode D _2, the choke coil L forming the integrating circuit, and the capacitor C ₂ .

The integrator circuit acts as a filter for high frequencies, and as shown in FIG. 4, the rise and fall of the pulse during the pulse oscillation of the laser are delayed, and the pulse waveform is distorted. Furthermore, if the pulse frequency fp is increased, adjacent pulses continue and the pulse command signal (Fig. A)
A DC voltage E ₂ (Fig. B) and a high frequency voltage E ₃ (Fig. C) having waveforms greatly different from the above are output. The present invention was devised with this point in mind. By changing the pulse modulation position to the subsequent stage of the DC converter unit 3, distortion of the pulse waveform is small over a wide range of the pulse frequency fp of the laser.
It is an object to provide a high frequency power supply for a laser oscillator.

[0007]

In order to achieve the above object, a high frequency power source for a laser oscillator according to the present invention comprises a direct current converter portion for converting direct current power into direct current power proportional to a laser output command, and the direct current converter A high-frequency inverter unit for converting electric power into a predetermined high-frequency power, and a switching unit for converting the direct-current power into pulse power proportional to the pulse wave command of the laser, between the DC converter unit and the high-frequency inverter unit. Is.

[0008]

With this configuration, the DC converter section converts the DC power into DC power proportional to the output command. In the switching unit, DC power is converted into pulse power without distortion that is proportional to the pulse wave output command. In the high frequency inverter section, the DC power of these continuous waves or pulse waves is converted into high frequency power of a predetermined frequency. Therefore, the output as the command signal is obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIG. As shown in the figure, the present invention includes a rectifying unit 1, a DC converter unit 3, a switching unit 5, a high frequency inverter unit 7, an output control unit 9, a gate drive unit 11, an output transformer T, a current sensor SI and a current signal generating unit SG. It consists of Hereinafter, differences from FIG. 3 described in the section of the related art will be described.

The switching section 5 is composed of a GTO (gate turn-off thyristor) and is controlled by a gate drive section 11 which inputs a pulse command signal of a laser. That is, the DC voltage E ₂ controlled and output by the DC converter unit 3 in response to the laser output command signal is controlled in response to the pulse command signal. The DC voltage E ₂ output from the switching unit 5 is converted into a predetermined high frequency AC voltage by the high frequency inverter unit 7, appropriately boosted by the output transformer T, and output to the laser discharge unit. The current of the discharging section is fed back to the output control section 9 via the current sensor SI and the current signal generating section SG.

As described above, since the pulse command signal does not pass through the DC converter unit 3, as shown in FIG. 2, a DC voltage E ₂ (b) and a high frequency voltage E ₃ are added to the pulse command signal (a). (Fig. C) corresponds exactly, and the waveform is not distorted. In this embodiment, the GTO element is used for the switching unit 5, but the same effect can be obtained by using the FET element (MOS transistor or bipolar transistor).

[0012]

As can be understood from the above description, since the present invention has the constitutions described in the claims,
It is possible to provide a high frequency power supply for a laser oscillator in which the pulse waveform is less distorted in a wide range of the laser pulse frequency. Therefore, it becomes possible to perform laser processing with an extremely high pulse frequency.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a high frequency power supply for a laser oscillator according to the present invention.

2 shows respective output voltages E ₂ (FIG. 2B) and E _{2 of} the DC converter unit 3 and the high frequency inverter unit 7 corresponding to the pulse command signal (FIG. 2A) of the high frequency power source for laser oscillator of the present invention.
It is the figure which showed ₃ (c figure).

FIG. 3 is a circuit diagram of a conventional high frequency power supply for a carbon dioxide laser oscillator.

FIG. 4 shows respective output voltages E ₂ (b) of the DC converter unit 3 and the high frequency inverter unit 7 corresponding to the pulse command signal (FIG. A) of the conventional high frequency power source for the carbon dioxide laser oscillator.
FIG) is a diagram showing E ₃ and (c diagram).

[Explanation of symbols]

 1 Rectification part 3 DC converter part 5 Switching part 7 High frequency inverter part 9 Output control part 11 Gate drive part

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[Procedure amendment]

[Submission date] May 14, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

The rectifying section 1 rectifies a 200 V commercial three-phase AC current and converts it into a smooth DC voltage E ₁ of about 250 V, and is composed of six diode groups D ₁ and a smoothing capacitor C ₁ assembled in a bridge. ing. DC converter unit 3
Is for converting the DC voltage E ₁ into a pulse or continuous waveform DC voltage E ₂ proportional to the command signal. The FET transistor TR ₁ , the feedback diode D ₂ , the choke coil L,
It consists of a capacitor C ₂ . High frequency inverter 7
Direct current voltage E ₂ frequency (fc) 100kHz ~ 27MH
Converts to a high frequency voltage E _{3 of} about z . 4 FE
T-transistors TR _{2 to} TR ₅ , high-frequency drive unit DR
And a high frequency oscillator GR.

Claims (1)

[Claims] 1. A DC converter unit for converting DC power into DC power proportional to a laser output command, a high-frequency inverter unit for converting the DC power into predetermined high-frequency power, and the DC converter unit and the high-frequency inverter unit. A high frequency power supply for a laser oscillator, comprising a switching unit for converting DC power into pulse power proportional to a laser pulse wave output command.