JPH0442794A - Thyristor ward-leonard apparatus - Google Patents

Abstract

PURPOSE:To return a motor to a normal operation with a short time interruption of the motor operation by a method wherein a fault detecting circuit, a fault discriminating circuit, a switching instruction circuit and a re-starting circuit are so provided as to switch one of first and second control units in which a fault occurs to a third control unit automatically for re-start operation. CONSTITUTION:In a normal operation, 6 pulse thyristors 4 which are connected in parallel with each other are controlled by first and second control units 12 and 17 to operate a DC motor 8. If a fault occurs in one of the first and second control units 12 and 17, the fault is detected by a fault detecting circuit 19 and the control unit in which the fault occurs is discriminated by a fault discriminating circuit 20 and is switched to a third control unit 18 which is separately provided by first, second and third switching circuits 22 - 24. After the switching is finished, the 6 pulse thyristors 4 are so controlled as to return to the normal operation by a start signal from a re-starting circuit 25.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thyristor Leonard device that can quickly restart a DC motor even in the event of a failure of a control unit.

[Conventional technology]

Figure 2 is a configuration diagram showing a conventional thyristor Leonard device. In the figure, 1 is an AC side breaker inserted into the power supply side, 2 is a three-phase transformer for the main circuit, and 3 is a block diagram that controls the current flowing in the main circuit. AC current transformer to detect (hereinafter referred to as ACCT),
4 is a 6-pulse thyristor, 5 is a DC reactor for smoothing the ripple in the output of the 6-pulse thyristor 4, 6 is a high-speed circuit breaker, 7 is a DC side disconnector, 8 is a DC motor, and 9 is directly connected to the DC motor 8. A pulse oscillator (hereinafter referred to as PLO) that oscillates a pulse proportional to the rotation speed of the electric motor, 10
11 is a field thyristor that supplies a field current to the field winding 10; 12 is a speed controller 13, a current controller 14, and generates a point appropriate signal for the 6-pulse thyristor 4; A first control unit 16 includes a gate pulse generator (hereinafter referred to as GPG) 15 and a gate pulse amplifier (hereinafter referred to as GPA) that amplifies the output of the gate pulse generator 15 to a level at which the 6-pulse thyristor 4 can actually fire. ), 17 is a second control unit consisting of a current controller 14 and a gate pulse generator 15.

Next, the operation will be explained. First, the AC circuit breaker 1, the high-speed circuit breaker 6, and the DC circuit breaker 7 are in an open state as operating conditions are satisfied by an operation command from a higher-level controller.

Therefore, in order to rotate the DC motor 8 at a desired rotation speed, a speed reference signal N is given to the speed controller 13 from a higher-level controller. At this time, the signal fed back from the pulse oscillator 9 and the speed reference signal N' are compared, and the difference between them is amplified and the current controller signals of the current controller 14 of the first control unit 12 and the current control signal of the second control unit 17 are changed. The current controller 14 compares the difference, amplifies the deviation, inputs it to the GPG 15, converts it to a phase signal, and then outputs the G
The pulse is given to P A I 6, further amplified, and the 6-pulse thyristor 4 is fired.

By controlling the point appropriate signal of this GPAI 6, the output voltage can be varied. In the case of 12-pulse operation, the outputs of the first control unit 12 and the second control unit 17 have a deviation of 30''.

[Problem to be solved by the invention]

Conventional thyristor Leonard devices are configured as described above, so if a failure occurs in one of the two sets of control units, the DC motor will become inoperable, leading to a shutdown of the production line and causing significant damage. The problem was to bring about this.

This invention was made to solve the above-mentioned problems. Even if one of the two sets of control units fails, the failed control unit can be immediately disconnected without stopping the production line, and a spare control unit can be installed. The aim is to obtain a thyristor Leonard device that automatically connects to a normal control unit equipped as a thyristor.

[Means to solve the problem]

The thyristor Leonard device according to the present invention has the following features: In addition to the second control unit, a third control unit is provided as a backup, and the first. a failure detection circuit that detects a failure when any one of the second control units develops a failure; A failure determination circuit that identifies which of the second control units is malfunctioning and outputs an identification signal; a switching instruction circuit that outputs a switching signal to a switching circuit described later based on the identification signal; and a switching instruction circuit that outputs a switching signal to a switching circuit described later. A first control unit that switches between a failed control unit and a third control unit by a switching signal.
．． a second and third switching circuit; 2nd and 3rd
and a restart circuit that outputs a restart signal upon receiving the switching signal output from the switching circuit.

[Effect]

In the thyristor Leonard device according to the present invention, under normal operating conditions, the 6-pulse thyristors connected in parallel are connected to the first thyristor and the first thyristor. Although the second control unit controls the DC motor, the first control unit operates the DC motor. When a failure occurs in either one of the second control units, the failure is detected by a failure detection circuit, the control unit that has caused the failure is determined by a failure determination circuit, and a third control unit provided separately is detected. The failed control unit is switched by the first to third switching circuits, and when the switching is completed, the 6-pulse thyristor is controlled to return to normal operation by a start signal from the restart circuit.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, parts that are the same as those in FIG. 2 are designated by the same reference numerals. In FIG. 12 or a failure detection circuit that detects a failure in the second control unit 17; 20 a failure determination circuit that determines in which control unit the failure has occurred; and 21 a failure control based on the output signal of the failure determination circuit 20. Normal third control unit 18 separated from the unit and provided as a spare
22 is a first switching circuit that switches the current feedback signal from ACCT 3, and 23 is the output of the first to third control units 12゜17.18. A second switching circuit 24 switches the first control unit 12 and the second control unit 17, or the first control unit 12 and the third control unit 18, or the second control unit 17 and the third control unit. The third switching circuit 25 that selects the unit 18 is a restart circuit that restarts the selected control unit upon receiving switching completion signals from the first to third switching circuits 22, 23, and 24.

Next, the operation will be explained. First, the basic operation is the same as that described in the prior art. In normal operation, the contacts 1 and 2 of the first switching circuit 22, the contacts 2 and 2 of the second switching circuit 23, and the contacts 2 of the third switching circuit 24 are closed. That is, 1st. Second control unit 12
．． 17 is selected. In this state, now the first
It is assumed that the control unit 12 of . The failure detection circuit 19 immediately detects a failure. At the same time, the failure determination circuit 20 investigates which control unit has failed, and when a determination signal indicating that the first control unit 12 has failed is output, the switching instruction circuit 21 disconnects the first control unit 12. , a control command is output to each switching circuit 22-24 to connect the third control unit 18. As a result, the first switching circuit 22 connects the contacts ■ and ■, the second
The switching circuit 23 has contacts ■ and ■, and the third switching circuit 24
In this case, the contacts ■ and ■ are closed, respectively. When the switching is completed, a switching completion signal is output from each switching circuit and the restart circuit 2 is output.
5 receives this signal and operates to restart the third control unit 18 and the second control unit 17.

〔Effect of the invention〕

As described above, according to the present invention, three sets of control units for 6-pulse thyristor control are provided, and normally the first... It is operated by the second control unit, but if a failure occurs in either one, it automatically switches to the third control unit and restarts operation. Since a starting circuit is provided, the motor can be stopped for a very short period of time to return to normal operation, and a highly reliable thyristor Leonard device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a thyristor Leonard device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional thyristor Leonard device. In the figure, 4 is a 6-pulse thyristor, 8 is a DC motor, 12, 17.18 is the first to third control unit, 19
20 is a failure detection circuit, 20 is a failure determination circuit, 21 is a switching instruction circuit, 22 to 24 are first to third switching circuits, and 25 is a restart circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a thyristor Leonard device that performs 12-pulse operation of a DC motor using 6-pulse thyristors connected in parallel and first and second control units that perform gate pulse control on the 6-pulse thyristors, the first and second a failure detection circuit that detects a failure when any one of the control units causes a failure; and a failure determination circuit that identifies which of the first and second control units is in failure and outputs an identification signal. , a switching instruction circuit that outputs a switching signal to a switching circuit to be described later based on the identification signal, and a switching signal from the switching instruction circuit that causes the failed control unit to be identified by the first control unit.
, first, second and third switching circuits for switching to a third control unit provided separately from the second control unit, and switching completion signals output from the first, second and third switching circuits. A thyristor Leonard device comprising: a restart circuit that outputs a restart signal for starting a six-pulse thyristor.