JPS61168279A - Output stabilizing circuit - Google Patents

Abstract

PURPOSE:To equalize the peak value at pulse output mode time to that at continuous mode time by inserting an attenuator for applying a relative attenuating degree N cooperation with the duty ratio N of a pulse into an output command route. CONSTITUTION:An attenuator 31 has a relative attenuator N which varies in cooperation with the duty ratio of a pulse generator 27. If the duty ratio N at pulse output mode time = 0.5, the output of the attenuator 31 becomes 0.5. Then, a comparator 33 compares the output current mean value 0.5 from a current transformer CT with the value 0.5 from an output command, PID- controls in a characteristic compensator 35, and controls the current flowing angle of a thyristor rectifier 21. Accordingly, the average value of the obtained pulses becomes 0.5, and the peak value becomes 1 similar to the continuous output mode time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an output stabilizing circuit for a power supply for laser oscillation.

[Technical Background of the Invention and Problems Thereof] There is a conventional output stabilizing circuit for a laser oscillation power source of a laser processing machine as shown in FIG.

This output stabilization circuit includes a feedback loop, including a thyristor rectifier circuit 1 that rectifies a commercial AC power supply, a smoothing circuit 3, a switching circuit 5, a pulse generator 7 that controls the switching circuit 5, and a laser discharger. An electrode 9 is provided as a power supply circuit section. In addition, the feedback loop for output stabilization detects the output current.
The thyristor rectifier circuit 1 includes a current transformer CT, a comparator 11, and a characteristic compensation circuit 13 that performs PTD control of the thyristor rectifier circuit 1.

To explain the operation of the above output stabilization circuit, the commercial power supply AC
The alternating current is rectified by the thyristor rectifier circuit 1, and then added to the smoothing circuit 3 to obtain a direct current, which is then intermittent according to the ON/OFF operation of the switching circuit 5 to obtain a direct current pulse output. Furthermore, if the switching circuit 5 is kept in the ON state, a continuous DC output instead of a pulse output can be obtained.

The thyristor rectifier circuit 1 has an input for controlling the conduction angle,
Output voltage can be controlled. The output current is detected by a current lance CT, compared with an output command in a comparator 11, and fed back to the thyristor rectifier circuit 1 through a characteristic compensation circuit 13 that performs PID control, thereby making the output a constant current.

Here, instead of making the output current constant, if the output voltage or output laser light is detected and fed back, the output can be made constant or the laser light output can be made constant.

Here, when the characteristic compensation circuit 13 is given an integral characteristic, when the switching circuit 5 is operated to pulse the output, the pulse detected by the current transformer CT and fed back is the average of the pulses (H) when passing through the integral circuit. Since the value indicating the output voltage is given to the L iris rectifier circuit 1, the average value of the output becomes constant.

This operation will be explained based on Fig. 5.If the output command is set to 10A, the switching circuit 5 will be turned on continuously.
In this case, since it is a direct current, the average value and the peak value are equal and both are about 10A. However, when the switching circuit 5 is operated and the output is a DC pulse, the average value and the peak value are different. For example, when the duty ratio of the pulse is set to 0.5, the peak value is 20A, which is twice the average value ( ,2ru.

In this way, in the case of conventional output stabilization circuits, the peak value of the output is different in continuous output mode and pulsed output mode, and when switching from continuous mode to pulsed mode, the peak value increases, causing abnormalities in the laser discharge section. There is a problem with inconveniences such as electrical discharge.

[Purpose of the Invention] The present invention was made in view of the above-mentioned conventional problems. The purpose of the present invention is to provide an output stabilization circuit that prevents inconveniences.

[Configuration of the Invention] The present invention includes a pulse generator and a switching circuit that switch between continuous output mode and pulse output mode, detects and feeds back output voltage, output current, or output light,
In the output stabilization circuit that maintains the average value of output voltage, output current, or output laser light constant depending on the characteristics of the characteristic compensation circuit, pulse generation is performed to equalize the peak value of the output in continuous horn mode and pulse output mode. This is an output stabilization circuit consisting of an attenuator whose relative attenuation +rt N changes in conjunction with the pulse duty ratio N of the generator, and which is inserted in the output command path, and whose relative attenuation +rt N changes in conjunction with the pulse duty ratio N of the pulse generator. By inserting an attenuator that provides a certain degree of attenuation, the peak value of the output command path in pulse mode is lowered, and the peak value of the actual pulse output is also kept low, thereby preventing problems in the laser discharge section. It is.

Embodiment of the Invention FIG. 1 shows a circuit of an embodiment of the invention. The configuration of this embodiment is almost the same as the output stabilizing circuit shown in FIG. 4 in the conventional example, except that an attenuator is provided in the output command path that provides an attenuation degree N that is linked to the pulse duty ratio N of the pulse generator. The difference is that . To explain the circuit of this embodiment, there is a thyristor rectifier circuit 21 that rectifies the commercial AC power supply AC, a smoothing circuit 23 that smoothes the rectified output of this thyristor rectifier circuit 21, and a smoothed DC that is turned on and off to produce a pulsed DC output. A power supply circuit is constituted by the switching circuit 25, a pulse generator 27 that controls ON/OFF of the switching circuit 25, and a laser discharge electrode 29 to which a pulse current is applied.

The feedback loop detects the output current from current 1 to
an attenuator 31 that changes the relative attenuation degree N in conjunction with the pulse duty ratio N of the pulse generator 27;
A comparator 33 that compares the output of the attenuator 31 with a current detection output from the current transformer CT, and a characteristic compensation circuit 35 that performs PTD control on the conduction angle of the thyristor rectifier circuit 21 based on the output from the comparator 33. There is.

To explain the operation of the output stabilizing circuit having the above configuration, AC power from a commercial power supply AC is rectified by the thyristor rectifier circuit 21 and converted into a continuous DC value by the smoothing circuit 23. The DC output from the smoothing circuit 23 is turned on and off by the switching circuit 25, and becomes a pulse output.

ON/OFF control of the switching circuit 25 is performed using pulses from a pulse generator 27. Therefore, if the pulse generator 27 is not a pulse but a continuous ON signal <1, the switching circuit 25 maintains the ON state and outputs a continuous DC output to the laser discharger 1! Give for i29. When the pulse generator 27 gives a pulse signal, the switching circuit 25 turns on and off, giving a DC pulse output to the sea 1f discharge electrode 29.

At this time, in the feedback loop, current 1 to lance CT
feeds back the output pulse signal to the comparator 33, where it is compared with the output command candy, and the deviation is determined by the characteristic compensation circuit 35.
given to. And the characteristic compensation circuit 35 is P r f)
The conduction angle of the thyristor rectifier circuit 21 is controlled by the control.

Here, since the attenuator 31 has a relative attenuation degree N that changes in conjunction with the duty ratio N of the pulse generator 27, the operation shown in FIG. 2 can be obtained.

When the duty ratio is N=1 in the continuous output mode and when the duty ratio N=0.5 in the pulse output mode, the attenuation degree of the attenuator 31 is 0.5 with respect to the output command 1 in the pulse mode, and this The output of the attenuator 31 becomes 0.5.

Therefore, the comparator 33 compares the output current average value 0.5 from the current transformer CT with the value 0.5 from the output command, performs PD control in the characteristic compensation circuit 35, and controls the current flow of the thyristor rectifier circuit 21. It controls the angle. Therefore, when the pulse duty ratio N=0.5 in the output pulse mode, the average value of the obtained pulse output is 0.5, and the peak value is 1 as in the continuous output mode.

FIG. 3 shows another embodiment of the present invention, in which the power supply circuit is equipped with a PWM switching circuit instead of the power supply circuit having the thyristor rectifier circuit 21 and the switching circuit 25. . To explain this PWM switching power supply circuit, a DC current is obtained from a commercial AC power supply AC by a rectifier circuit 41 and a smoothing circuit 43,
This turns on and off in the carrier switching circuit 45.
It is controlled by FF, and is output as a continuous output or a pulse output including the Q/R signal, and is passed through the transformer 47, the rectifier circuit 49, and the smoothing circuit 51, where carriers are removed and the laser discharge electrode 53 is output in continuous mode, Alternatively, a pulse mode output is provided.

The feedback loop includes a comparator 55 that compares the output current obtained by the current transformer CT with an output command value, a characteristic compensation circuit 57, and a high frequency PWM carrier generator 59. Further, the high frequency PWM carrier generator 59 is connected to the carrier switching circuit 45 via the circuit 61 to the gate circuit 61, and the pulse generating circuit 63 is connected to the gate circuit 61.
is also connected. Further, an attenuator 65 is inserted in the output command path to provide the output command with a relative attenuation degree N that changes in conjunction with the pulse duty ratio N of the pulse generation circuit 63.

In the case of the output stabilizing circuit of the PWM switching power supply having the above configuration, the high frequency carrier from the high frequency PWM carrier generator 59 is passed through the circuits 1 to 61 to the pulse generating circuit 63.
The carrier switching circuit 4 is superimposed with the pulse from
5, and a pulse output according to the pulse mode generated by the pulse generating circuit 63 can be obtained.

In the case of this embodiment as well, waveforms as shown in FIG. 2 are obtained at each part, and the peak value in the pulse output mode is controlled to be equal to the peak value in the continuous output mode.

[Effects of the Invention] This invention inserts an attenuator in the output command path that provides a relative attenuation degree N in conjunction with the pulse duty ratio N of the pulse generator. The output command value can be attenuated by N in conjunction with the duty ratio N, and the average output value can be lowered accordingly, and the peak value in pulse output mode can be controlled to be equal to the peak value in continuous mode. can do. This has the advantage of preventing inconveniences such as the peak value being large when switching from the continuous mode to the pulse mode, which occurs in the rake "discharge section" when switching from the continuous mode to the pulse mode. be.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram of an embodiment of the present invention;
Figure 3 is a circuit block diagram of another embodiment of the present invention, Figure 4 is a circuit block diagram of a conventional example, and Figure 5 is a diagram illustrating the operation of the conventional example. This is an explanatory time chart. 21...4f iris rectifier circuit, 23...smoothing circuit, 25...switching circuit, 27...pulse generator 1
(: device, 29... laser discharge electrode, 31... attenuator, 33... comparator, 35... characteristic compensation circuit, 41...
... Rectifier circuit, 43 ... Smoothing circuit, 45 ... Carrier switching circuit, 47 ... Transformer, 49 ... Rectifier circuit, 51 ... Smoothing circuit, 53 ... Laser discharge electrode, 55 ... Comparator, 57 ... Characteristic compensation circuit, 59
...High frequency PWM carrier generator. 61... Goo 1, 63... Pulse generation circuit, 65
...attenuator. Pusoo-Aζn-

Claims (1)

[Claims] Equipped with a pulse generator and a switching circuit that switch between continuous output mode and pulse output mode, detects and feeds back the output voltage, output current, or output light, and adjusts the output voltage, output current, or laser output light depending on the characteristics of the characteristic compensation circuit. In an output stabilization circuit that keeps the average value constant, the relative attenuation degree N changes in conjunction with the pulse duty ratio N of the pulse generator in order to equalize the output peak values in continuous output mode and pulse output mode. An output stabilization circuit consisting of an attenuator inserted into the output command path.