JPS61227688A - Thyristor power source - Google Patents

Abstract

PURPOSE:To prevent a thyrsitor converter from causing the commutation failure on momentary service interruption, by breaking regenerative power with a self-arc-suppressing switching circuit provided between the thyristor converter and a smoothing condenser, when the momentary power interruption occurrs during regenerative operation. CONSTITUTION:Between a thyristor converter 3 and a smoothing condenser 7, a diode 9 and a self-arc-suppressing switching element 8 are connected in series to be inserted. An AC power source 1 is provided with a voltage detector 11, and the detected value of the voltage detector 11 is compared with the set point of a detection level setting device 13 by a momentary power interruption detection circuit 13 to detect the momentary power interruption. When the momentary power interruption occurrs, then if devices are under regenerative operation, the self-arc-suppressing switching element 8 is turned OFF just during the momentary service interruption and regenerative current is broken. In this manner, even if the commutation failure of the thyristor converter 3 is caused, short-circuit current is not generated.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a thyristor power supply device.

[Background of the invention]

As a conventional thyristor power supply device, a transformer power supply is equipped with positive and reverse thyristor converters, a smoothing capacitor is connected to the DC output side of these thyristor converters, and it is possible to regenerate power from the motor that is the load. There is. On the other hand, when a commercial AC power source is used as the AC power source, a momentary power outage may occur, which is a power outage for an extremely short period of time. If such a momentary power outage occurs during regenerative operation of a conventional thyristor power supply, the AC power supply voltage will drop below the voltage from the load, causing the thyristor converter to fail in the intended commutation, resulting in a DC short circuit. There was a problem. Regarding regenerative operation of inverter devices, Japanese Patent Application Laid-Open No. 1986-
There is a publication No. 42237.

Furthermore, after a momentary power outage is restored, the DC output voltage of the thyristor converter and the voltage of the load do not necessarily match, resulting in overvoltage on the load side, inrush current to the smoothing capacitor, or commutation failure. There was a problem.

As described above, the conventional thyristor power supply device has various problems because it does not take any measures against momentary power failure.

[Purpose of the invention]

An object of the present invention is to provide a thyristor power supply device that does not cause commutation failure of a thyristor converter even when a momentary power outage occurs.

Another object of the present invention is to provide a thyristor power supply device that can be restarted smoothly upon recovery from a momentary power outage.

[Summary of the invention]

In order to achieve the above object, the thyristor power supply device according to the present invention interrupts regenerative power by a self-extinguishing switching circuit provided between a thyristor converter and a smoothing capacitor when a momentary power outage occurs during regenerative operation. That's what I do.

Furthermore, the thyristor generator according to the present invention applies a bias signal corresponding to the voltage between the terminals of the smoothing capacitor to the control signal of the thyristor converter during a momentary power outage, thereby
The system is set to restart immediately after the power is restored.

[Embodiments of the invention]

A thyristor power supply device according to an embodiment of the present invention is shown in FIG. 1. A positive side thyristor converter 2 and a reverse side thyristor converter 3 are connected to an AC power source 1, and AC voltage is converted into DC voltage. A smoothing capacitor 7 is connected to the DC side to smooth the output DC voltage. Further, an inverter composed of a GTO thyristor converter 4 and a diode circuit 5 is provided on the load side, and an induction motor 6 is connected to this inverter.

゛ A control circuit is provided for such a main circuit configuration. In this control circuit, an automatic voltage setting circuit 16 and an automatic pulse circuit 14 operate to provide gate pulses to the thyristor converters 2 and 3 so that the DC output voltage is set by the voltage setting device. On the other hand, on the inverter side, the automatic setting device 20 controls the gate current of the GT◯ thyristor converter 4 based on the speed setting value by the speed setting device 21, and the speed of the electric motor 6 is controlled.

Furthermore, in this embodiment, a diode 9 and a self-extinguishing switching element (for example, a GTO thyristor, a power transistor electrostatic thyristor, etc.) 8 are inserted in series between the thyristor converter 3 and the smoothing capacitor 7. . In addition, a voltage detector 11 is provided in the transformer power supply 1, and the detected value of the voltage detector 11 and the set value v of the detection level setter 13 are
The instantaneous power outage is detected by comparing it with 2 in the instantaneous power outage detection circuit 12. The detection output of the instantaneous power failure detection circuit 12 turns on the switch 18 and turns off the switch 15. Further, the voltage between the terminals of the smoothing capacitor 7 is determined by the DC voltage detection circuit 19.
has been detected by.

Next, the operation will be explained. When a speed setting value is given by the speed setter 21, a speed command as shown in FIG. 2 is given by the automatic setter 20. It accelerates from time T to T1, drives at a constant speed from time T1 to T2, and decelerates from time T2 to T3. The actual speed of the electric motor 6 is shown by the broken line in FIG. Therefore, from time T0 to T2
Until then, it is normal operation in which power is supplied from the thyristor power supply device to the motor 6, but from time T2 to T3, power is supplied to the motor 6 from the thyristor power supply device.
During normal operation, the GTO thyristor 8 is turned off and current flows through the diode 9, but during regenerative operation, the GTO thyristor 8 is turned on and regenerative current flows.

This is normal operation without momentary power outage, but
When a momentary power outage occurs, as shown in FIG. 2, if regenerative operation is in progress, the GTO thyristor 8 is turned off only during the one-hour power outage to cut off regenerative power. As a result, even if commutation failure of the thyristor converter 3 occurs, no short-circuit current is generated.The operation at the time of a momentary power outage during the 1° regenerative operation will be described in more detail with reference to FIG. vl is the voltage detection value of the AC power supply 1, and v2 is the detection level setter 13
Vz' is the level at which the thyristor cannot commutate, v3 is the control signal to the switch 15, ■4 is the control signal to the switch 18, and ■, is the level to the automatic setting device 20. is the suppression signal, and ■ is the GTO
This is the extinguishing signal to thyristor 8, and V(1?. is GTO
It shows the actual extinguishing state of the thyristor 8, and vo is the signal to the automatic pulse generator 14; . is the regenerative current.

Now, when an instantaneous power outage occurs at time t0 during regenerative operation and the detected voltage value v1 begins to decrease and falls below the set value v2 at time t1, the instantaneous power outage detection circuit outputs signals v1 to v6. The switch 15 is turned off by the signal v3, and the switch 18 is turned on by the signal v4. Thereby, a voltage corresponding to the voltage between the terminals of the smoothing capacitor 7 is inputted to the automatic pulse generator 14 as a bias voltage. Therefore, a bias voltage is applied to the control signal of the automatic pulse generator 14. The automatic setter 20 is suppressed by the signal V. The GTO thyristor 8 is forcibly turned off by the signal v1, and the current flows from the smoothing capacitor 7 to the thyristor converter side. .

cut off. Note that the actual turn-off of the GTO thyristor 8 is a little delayed, but the time is about 200 to several hundred μs, which is generally much earlier than the power drop during a momentary power outage. .

It is possible to block the

Conventionally, when the thyristor converter 3 fails to commutate at time t2, a short circuit occurs, causing a short circuit current to flow and causing an accident.

From time t2 to time t□, the power supply voltage is decreasing, so the thyristor converter 3. Both inverters are kept in a suppressed state. During this time, the voltage between the terminals of the smoothing capacitor 7 is detected, and the voltage is set to 2 (, = 2), and the system waits until the power is restored.

When the power supply voltage recovers and becomes larger than the set value v2 at time t3, the signal V, ~v6 returns to its original state, and at time t
, at the electrician. begins to flow again as a normal regenerative current. Since the system is on standby so that v0=v7 until the power is restored, the optimal firing angle of the thyristor can be given even after the power is restored, and commutation failure will not occur.In this way, according to this embodiment, Even if a momentary power outage occurs during regenerative operation, the thyristor will not fail in commutation, and short-circuit accidents can be prevented. Furthermore, even after a power outage is restored, the optimal firing angle can be given to the thyristor, allowing for smooth restart.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the present invention. For example, the present invention can be applied to a thyristor power supply device without an inverter for driving a DC motor.

〔Effect of the invention〕

According to the present invention, even if a momentary power outage occurs during regenerative operation,
This prevents short-circuit accidents and enables smooth operation after recovery.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a thyristor power supply device according to an embodiment of the present invention, and FIGS. 2 and 3 are time charts illustrating the operation of the thyristor power supply device. 1... AC power supply, 2, 3... Thyristor converter, 4
...GTO thyristor converter, 5... Diode circuit, 6... Electric motor, 7... Smoothing capacitor, 8...
・GTO thyristor, 9...diode, 11...
voltage detector. 12... Momentary power failure detection circuit, 13... Detection level setter, 14... Automatic pulse generator, 15... Switch, 16... Automatic voltage setting circuit, 17... Voltage setting device, 18... Switch, 19... DC voltage detection circuit, 20... Automatic setting device, 21... Speed setting device.

Claims (1)

[Claims] 1. An AC power source, a positive side thyristor converter and a reverse side thyristor converter connected to the AC power source, and a smoothing capacitor provided on the DC output side of these thyristor converters, In a thyristor power supply device configured to regenerate electric power from an electric motor as a load, an instantaneous power failure detection circuit for detecting a momentary power failure of the AC power source is inserted between the DC output side of the thyristor converter and the smoothing capacitor. and a self-arc-extinguishing switching circuit that turns on during regenerative operation of the electric motor, and when a momentary power failure is detected by the instantaneous power failure detection circuit during regenerative operation,
A thyristor power supply device characterized by turning off a front switching circuit and cutting off regenerative power from an electric motor. 2. Equipped with an AC power source, a positive side thyristor converter and a negative side thyristor converter connected to this AC power source, and a smoothing capacitor provided on the DC output side of these thyristor converters, and is equipped with In a thyristor power supply device configured to perform regeneration, a momentary power failure detection circuit detects a momentary power failure of the AC power supply, a voltage detection circuit detects a voltage between the terminals of the smoothing capacitor, and a voltage detected by the voltage detection circuit. and a bias circuit that applies a bias signal corresponding to the voltage between the terminals to the control signal of the thyristor converter, and while a momentary power failure is detected by the momentary power failure detection circuit, the bias circuit applies the bias signal to the control signal of the thyristor converter. A thyristor power supply device characterized in that it is applied to a control signal of a converter.