JPS62225197A - Motor control device - Google Patents

Abstract

PURPOSE:To improve the reliability(rate of operation) of a whole unit and at the time to put the unit to operation on normal side without stopping the whole unit and to build up the unit on fault side to operation, by dividing a converter to provide multiple units. CONSTITUTION:In case a fault detection circuit built in the circuit of a converter 21 actuates, contactors 71 and 81 are opened, and inverters 51a-51n are released from power source and stopped at the same time. Meanwhile, a converter 22 on normal side is not to be stopped, but to continue the opeation establishing the output on converter side. There, the contactors 71 and 81 are opened and a contactor 10 is closed, while a contractor 11 is opened on the condition that the motor has stopped. After a time specified, the contactor 11 is closed. In this state of things, inverters 51a-51n are resumed to operate provided that the contractor 11 remains closed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a motor control device having a converter that uses a common power supply system for a plurality of motors, and an inverter that controls each motor.

(Conventional technology) A converter converts AC power from a commercial power source to DC, and an inverter converts it to variable voltage and frequency.

When converting AC power to control a motor, it is possible to adopt a so-called common power supply system in which DC power is supplied to a plurality of inverters using one converter due to the configuration of the device.

In particular, when each electric motor is operated with an intermittent load, this is an effective means for a load-throwing machine or the like where the converter capacity does not require only the load capacity of the entire electric motor.

However, in this conventional device, one converter drives multiple inverters, so if one converter fails, the electric motor of the entire device will stop, reducing the reliability (operational performance) of the entire device. There was a problem that the rate) decreased.

(Problem to be Solved by the Invention) In order to solve this problem, the present invention provides an electric control device that can divide the electric motor according to the device configuration, provide multiple converters, and improve the operating rate of the device. I will provide a.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides AC power to a plurality of converters, contacts for connecting the converters, contacts for connecting the respective converters and inverters divided into the number of converters,
This is a motor control V& unit that includes a resistor connected in series with a contact that connects the converters, and a contact that shorts the resistor.

(Function) In a device configured as described above, if one of the multiple converters fails, the multiple inverters connected to the failed converter are stopped, and the normally operating ones are stopped. It is now possible to restart the device by reconnecting it to the converter on the other side, or to completely stop the device and connect the inverter group that was connected to the faulty converter to the normal converter. There is no need to make the inverter ready for operation.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 shows the configuration. 1 is a power supply, 21.22 is a divided converter, 31.32 is a divided capacitor, 41a to 41n, 42a to 42n are branch switches, 518 to 51n, 52a to 52n are divided inverters , 61a to 61n, 62a to 62n are electric motors, 71.72 is a contactor that separates the power supply 1 and the converter 21.22, and 81 is the converter 21 and the converter 21.
A contactor 82 connects the inverters 51a to 51n connected to the converter 22 and the inverters 52a to 52n connected to the converter 22;
are inverters 51a to 51n and inverters 52a to 52
The contactor 12 that connects the contactor 10 is a contactor that is connected to short-circuit both ends of the resistor 12 that is connected in series with the contactor 10.

Normally, contactors 71.72 and 81.82 are closed, contactor 10 is open, converter 21 and inverters 51a to 51n, converter 22 and inverter 52a
~52n is connected and is being operated.

When the failure detection circuit built into the circuit of the converter 21 is activated, the contactor 71.81 is opened and the inverter 51a is opened.
~51n is stopped at the same time as it is disconnected from the power supply. On the other hand, the converter 22 on the normal side is not stopped and continues to operate while establishing the converter side output.

Here, on the condition that the contactors 71 and 81 are opened and the motor has stopped, the contactor 10 is opened and the contactor 11 is opened.
The contactor 11 is closed after a set time by a time relay (not shown).

In this state, the inverters 51a to 51n are connected to the converter 21, and the inverters 51a to 51n resume operation on the condition that the welder 11 is in a closed circuit state.

At this time, since the converter 21 is outputting the rated voltage, the resistor 12 is provided to prevent a rush current from flowing if a voltage is suddenly applied to the capacitor 31. if,
If this resistor 12 is not present, converters 21 and 22
It is necessary to stop both of the DC voltages and establish the voltage while controlling so that no rush current flows into the capacitors 31 and 32 from the state where the DC voltage is reduced.

Although the above description has been made for the case where the converter 21 fails, the same applies even when the converter 22 side fails.

By configuring the device in this way, even if one converter fails, the other can continue operating, and at the same time, the failed inverter can be disconnected and connected to the failed converter without stopping the other converter. It is possible to resume operation by connecting the inverter that was in use to the other normal converter.

For example, a converter failure detection circuit can automatically open, close, disconnect, and connect a circuit, providing an effective means for saving labor and continuing operation.

FIG. 2 shows another embodiment.

This is an example in which a resistor and a contactor for shorting the resistor are installed separately.

〔Effect of the invention〕

As detailed above, according to the present invention, in the case where the overall configuration of the device can be divided and installed due to the converter capacity, the reliability (operating rate) of the entire device can be improved by dividing the converter and installing multiple units. At the same time, it becomes possible to bring the normal side into operation and bring the faulty side into operation without stopping the entire device, making it possible to provide a practical device that can perform continuous work.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a motor control device showing one embodiment of the present invention, and FIG. 2 is a block diagram of a motor control device showing another embodiment. 1... Power supply 21.22... Converter 31.32... Capacitors 41a-41n, 42a-42n-Switches 51a-51
n, 52a to 52n...inverters 61a to 61n,
62a-62r+-Electric motor 71.72,81,82...
・Magnetic contactor 11, 111, 112...Magnetic contactor 1
2.121,122...Resistor agent Patent attorney Noriyuki Chika Ken Yudo Mitsumata Hirofumi Figure 1

Claims (1)

[Claims] In a motor control device that consists of multiple converters that convert AC power to DC, multiple inverters connected to these converters, and a motor that is operated with variable voltage/variable frequency power output from the inverters. ,
A motor control including a connection circuit connecting between the plurality of converters, an inverter divided and connected to the converter, a resistor provided in the connection circuit, and a contactor short-circuiting the resistor. Device.