JPH02103977A - Power source for pulsed laser - Google Patents

Abstract

PURPOSE:To detect abnormality in operation at an early period and to prevent breakdown of a laser apparatus by using capacitors in a magnetic compression circuit as voltage dividers, providing voltage monitoring windings in saturable reactors, and providing a current monitor between the capacitors and the ground. CONSTITUTION:Capacitors 16 and 17 at each stage of a magnetic compression circuit are used as voltage dividers. Voltages which are proportional to rise-up voltages are outputted. Current transformers 20 and 21 are provided for lead wires for connecting the capacitors 16 and 17. The moving state of electric charge is taken out as a voltage output. Monitoring windings 22 and 23 are provided around saturable reactors 18 and 19. The voltage outputs caused by the currents of main circuits are supplied to a monitoring device 26 through protecting impedances 24 and 25. the accumulated energy in the capacitor 17 at the final stage is sent into a laser device 27 through the reactor 19. In this way, a power source for pulsed laser which detects abnormality in operation at an early period and prevents the breakdown of the laser device is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objectives of the Invention) (Industrial Application Field) The present invention relates to a pulsed laser power supply that has an improved operation monitoring system for a pulsed laser power supply circuit.

(Prior Art) In recent years, various lasers such as TEA and TEMACO2 lasers, excimer lasers, and copper vapor lasers have been considered for industrial use, and at the same time, excellent pulse power sources for these lasers have been required. It looks like this. In addition, a similar power supply is used for accelerator Fast Pulsed)iag
It is also sought after for use on the internet.

Such a large current/pulse power supply requires a fast current rise (
100KA/1t sec), large current (~10KA
), high voltage (~150KV), saturable reactor (several MH2) with low impedance and high reactance ratio
The characteristics described above are sufficient to respond, and have a large ratio of inductance between saturation and non-saturation), very narrow pulse width (ioons), and jitter time (several + n5ec).
(below) and long life (approximately 108 to 11 or more).

The electric circuit shown in FIG. 2 was devised for the above purpose. In the electric circuit shown in FIG. 2, the low voltage side of the pulse transformer 11 is a switch circuit for generating pulse current, and the high voltage side is a magnetic pulse compression circuit (Magnetic pulse compression circuit).
Pulse Compression = MPC
It is an electrical circuit called a circuit.

In the switch circuit formed on the low voltage side of the pulse transformer 1 shown in FIG.
4 and rectifiers 5 to 7, and three capacitors 8 to 10 are connected in parallel to the low voltage side of the pulse transformer 11. In addition, thyristors 12 to 1, which are switching elements,
4 is adapted to be ignited by a driver 15.

The operation of such a switch circuit is as follows: First, the charging N power supply 1
Accordingly, the charging reactor 2, 3.4 and the rectifier 5,
6.7, the capacitor 8°9.10 is always charged to a constant voltage. Here, by firing the thyristors 12 to 14 one after another by the driver 15 so that the frequency required for the entire power supply is achieved, the low voltage side of the pulse transformer 11 is supplied with a pulse current at the required number of repetitions. occurs.

In the example shown in Figure 2, the number of thyristors is three (that is, the circuit connected to the low voltage side of the pulse transformer is three in parallel), but this is due to the number of repeated pulses required for the power supply and the number of thyristors. Choose an appropriate number depending on your abilities. For example, a general thyristor has a frequency of several hundred Hz, 1kllZ
It is necessary to use it at a repetition frequency of about 100%. Therefore, for example, when the repetition frequency is 5 kHz, the number of thyristors in parallel is 7 to 10 or more.

In addition, in Fig. 2, the switching element for generating a repetitive pulse current is not limited to a thyristor, but a mechanical switch is used as the switching element under the severe conditions described above. However, there are problems in terms of lifespan and jitter, and in the end thyristors are the most suitable.

The switch element used in such a switch circuit plays the role of transmitting energy from the charging power supply to the MPC circuit side with a constant pulse width, and a thyratron or a semiconductor is considered to be optimal for this switch element, but the above-mentioned In high voltage power supply circuits such as
Therefore, a large switch must be used.

On the other hand, the MPCl path on the high voltage side of the pulse transformer 11 is connected to capacitors 16 and 17 of appropriate values and saturable reactors 18 and 1.
9 are combined in two stages, and the time width of the current input from the low voltage side of the pulse transformer 11 is sequentially compressed by the circuits in each stage. With this configuration, by reducing the time width of the current input from the low voltage side of the pulse transformer to about 1/100, the rate of increase in current can be increased to the above-mentioned 100 kA/μsec or more.

To describe the operation of the high voltage side of the pulse transformer 11 in detail, when voltage is generated on the high voltage side of the pulse transformer 11,
The interelectrode voltage of the first stage capacitor 16 increases in proportion to this voltage. As a result, a small amount of current flows into the first stage saturable reactor 18 in proportion to the voltage between the poles of the capacitor 16, but when this current reaches a certain value, the magnetic flux in the iron core of the saturable reactor 18 becomes saturated magnetic flux. If you are above the density,
The saturable reactor 18 becomes saturated, the inductance rapidly decreases, and the energy stored in the capacitor 16 is transferred to the second stage capacitor 17 via the saturable reactor 18. In this case, by sequentially decreasing the inductance of the saturable reactors 18 and 19 in each stage during non-saturation and saturation, the frequency of the current flowing through each stage can be sequentially increased to a higher frequency.

By the way, the relationship between the first-stage capacitor 16, the first-stage saturable reactor 18, and the second-stage capacitor 17 is such that when the saturable reactor 18 is non-saturated, the frequency of the current flowing through this loop is single stage capacitor 16
By setting the impedance of the first stage saturable reactor 18 and the non-saturated impedance of the first stage saturable reactor 18 to appropriate values, the first stage capacitor 16 to the second stage capacitor 17
The timing at which energy is transferred to the saturable reactor 18 can be adjusted, and the impedance when the saturable reactor 18 is saturated is made sufficiently larger than the impedance of the second stage capacitor 17 at the current frequency flowing when the saturable reactor 18 is saturated. Accordingly, almost all the energy of the first stage capacitor 16 can be transferred to the capacitor 17.

Similarly, when the saturable reactor 19 is saturated, the energy transferred to the capacitor 17 flows toward the laser device @ 27 and generates a laser discharge.

(Problem to be solved by the invention) As described above, energy transfer is performed depending on the impedance relationship, but it cannot be judged from the outside whether it is actually operating or whether energy is being sent to the laser device in the correct operation. I could not do it. If the magnetic compression circuit did not operate normally, there was a risk of damaging the laser device.

Therefore, the present invention was proposed in order to eliminate the above-mentioned drawbacks.The purpose of the present invention is to monitor the operation of the magnetic compression circuit from the outside, detect abnormalities at an early stage, and protect the laser device. Its purpose is to provide power supplies for lasers.

(Structure of the Invention) (Means for Solving the Problems) The pulse laser power supply of the present invention uses a capacitor of a magnetic compression circuit as a voltage divider, and a saturable reactor is provided with a monitoring winding for monitoring the voltage. A current monitor is provided between the stage capacitor and ground to detect the magnetic compression circuit input frequency, operating voltage, and operating state of the saturable reactor.

(Function) According to the present invention having the above configuration, the operating state of each stage of the magnetic compression circuit and the operation of the saturable reactor of each stage can be detected, and abnormalities in operation can be detected at an early stage. It becomes possible.

(Embodiment) An embodiment of the present invention will be described below based on FIG. 1. Note that the same parts as in the conventional one shown in FIG. 2 are given the same reference numerals, and the explanation will be omitted.

In this embodiment, as shown in the circuit diagram of FIG.
The capacitors 16, 17 in each stage of the magnetic compression circuit are used as a voltage divider to output a voltage that is proportional to the voltage rising across each capacitor 16, 17. A current transformer (CT) 20.21 is installed on the lead wire connecting each capacitor 16.17 of the magnetic compression circuit to the ground, and the current flowing through each circuit outputs the state of charge movement as a voltage output.

Each saturable reactor 18.19 has a saturable reactor 1
The monitor windings 22 and 23 are wound several times around the iron cores 8 and 19, and a voltage output is outputted via the protective impedance 24 and 25 by the magnetic flux generated by the current flowing to the main circuit side. The output of that ax is input to a monitoring device 26. The energy stored in the final stage capacitor 17 is sent to the laser device 27 by the operation of the saturable reactor 19.

In the pulse laser power supply of this embodiment having such a configuration, each stage capacitor 16 of the magnetic compression circuit shown in FIG.
．． 17 can be constantly monitored, and in the same way, the current flowing through each capacitor 16 and 17 can be monitored. Further, by constantly monitoring the voltage generated in the monitor winding 22.23 by the magnetic flux generated by the current flowing through the saturable reactor 18.19, the operation of the saturable reactor 18.19 in each stage can be known.

In this way, when the pulse laser power supply of this embodiment is used, abnormalities in circuit operation can be detected early by constantly monitoring the current, voltage, and operation of the saturable reactor at each stage of the magnetic compression circuit. As described above, it is possible to obtain a pulsed laser power supply that constantly monitors the operation of the magnetic compression circuit and prevents damage to the laser device due to abnormalities in the power supply.

〔Effect of the invention〕

As described above, according to the present invention, the operation of the magnetic compression circuit can be constantly monitored, abnormalities in the circuit operation can be detected early,
It is possible to provide a pulsed laser power supply that prevents damage to the laser device due to power supply abnormalities.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of a pulsed laser power supply circuit of the present invention, and FIG. 2 is a circuit diagram showing an example of a conventional pulsed laser power supply circuit. DESCRIPTION OF SYMBOLS 1... Charging power supply of switch circuit, 8-10... Capacitor, 11... Pulse transformer, 12-14... Switch element (thyristor), 15...
...Driver, 20, 21...Current transformer, 18,
19... Saturable reactor, 22, 23... Monitor winding,

Claims (1)

[Claims] In a pulsed laser power supply having a switch circuit in which a switch element is connected to a capacitor connected to a charging power supply, and a magnetic pulse compression circuit in which a saturable reactor and a capacitor are connected to a laser discharge section, the capacitor in the magnetic pulse compression circuit is A pulsed laser power supply circuit characterized in that it is used as a voltage monitor.