JPS62268372A - Motor controller - Google Patents

Abstract

PURPOSE:To exactly stop a motor on power interruption, by connecting a controller to a power feed section in order to use the regenerative energy of the motor on the service interruption of a main AC power source and generate the output of motor stop control signal to a converter. CONSTITUTION:When power interruption occurs, power supply to a converter 4 is turned OFF. At the same time, from a power interruption detector 10, the output of power interruption command to a controller 8 is generated, and from the controller 8, the output of motor stop control signal to an inverter 7 is generated. A motor 2 goes into a stop action, and power is generated by rotation due to inertia. The power is inverted by the inverter 7, and is regenerat ed to a main DC power source section 6. By this regenerative energy, the control ler 8 is driven via a DC/DC converter 9. The controller 8 is not stopped because of the regenerative energy, and the output of the motor stop control signal to the inverter 7 is continuously generated. This action is continued till the motor 2 is completely stopped.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a seven-motor control device, and in particular to a motor control device configured to reliably stop the motor without causing ff boiling during a power outage. Regarding.

(Conventional technology) Generally, the -ri is rotated by power supply.

Therefore, in the event of a power outage, the motor will stop because no power is supplied, but if a power outage occurs while the motor is rotating, the motor itself and the machine cannot be stopped suddenly due to the action of the drive shaft. Due to this inertia, machines often perform unnecessary operations for long periods of time, or run out of control beyond the limits of the machine, resulting in many accidents that result in serious damage. In particular, FA robots have become widely used as the core of factory automation in recent years, but the arms of these robots are also driven by motors, so if a power outage occurs, the arms can become uncontrollable and run out of control, causing serious problems. There was also the risk of a major disaster.

In view of these circumstances, the following h-formula has been proposed as a means for stopping the motor before a power outage. The first is a friction braking system. This is usually called an electromagnetic brake or a mechanical brake, and its structure is such that a friction plate that rotates at the same time as the motor contacts a separately provided braking mechanism to generate a frictional braking force to stop the motor. This is what I did. According to this method, braking is performed during a power outage, but the braking mechanism is based on a friction plate! ! It has the disadvantage of causing surface wear,
In addition, maintenance such as adjustment and maintenance of the gear knob on the machining surface is required, making it a hassle. In addition, when applied to machine tools or robot arms with large inertia, the brake must be relatively large and powerful.
There is a limit to miniaturization, and this is also a factor leading to a large amount of storage space. In addition, particularly when performing servo control, the friction plate becomes a source of large excess inertia, which also has the disadvantage of impairing high responsiveness during normal operation.

On the other hand, an electric braking system has also been proposed as an alternative to the above-mentioned braking system using friction. This is usually called a dynamic braking system, and the configuration of E is 4 + electric power generator lJ-, II; 'I is rotated by inertia -[-Y] is made to act as a generator, and this generated 1 energy is incorporated into the circuit. It is designed to stop by being consumed by resistance.

According to this H type, the problem of the friction braking method described above is solved because it does not have a mechanical friction plate, but the braking force is also proportionally lower at low speeds or when the speed is decreasing. 1. This is because as the speed decreases, the electromotive force decreases, so the current flowing through the resistor also decreases. In addition, in recent years, induction motors have become widespread because they require no maintenance, have a simple and robust structure, and are capable of excellent servo control. This method can be easily applied to a DC motor or a synchronous motor in which the motor itself has a magnet, but cannot be easily applied to an induction motor that does not have a magnet.

(Problems to be Solved by the Invention) As described above, the conventional dynamic braking system has problems in braking during power outages and in application to various motors.

The present invention aims to solve the above-mentioned problem, and aims to provide a motor control device that can reliably stop the motor without any delay in the event of a power outage.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a power supply unit 3 having a converter 4 for converting main AC power into main DC power, and
A motor control device 1 comprising a converter 7 connected to a converter 7 for converting the main DC power supply to a motor drive current path, and a control device 8 for outputting a motor control signal to the converter 7, - [1-ru device 8 is connected to the power supply unit 3 in order to output a motor stop control signal to the converter 7 by using the regenerated energy of the motor 2 in the event of a power outage of the main AC power supply. be.

(Function) When the main AC power supply is out of power, the present invention guides regenerative energy due to the inertia of the motor 2 to the power supply section 3, and uses this regenerated energy to drive the control device 8 connected to the power supply section 3. A motor stop control signal is output to the converter 7 to make vc<j, and the motor 2 is stopped without stopping the control device 8 due to a power outage.

(Example) Hereinafter, an example in which the present invention is applied to a control device for a three-phase induction motor will be described in detail with reference to the drawings.

In FIG. 1, 1 indicates a motor control device, and 2 indicates a motor connected to this motor control device 1, which is a three-phase induction motor.

The motor control device @1 includes a power supply section 3, and this power supply section 3 has a converter 4. This converter 4 has a capacitor therein for storing regenerative energy, is connected to a three-phase FFI line (not shown), and connects the main AC power supplied to the main AC power supply 5 to the main DC power supply 6. Provided for converting to main DC power. 7 is an inverter which is a converter, and this inverter 7 is connected to the main DC power supply section 6 and the motor 2,
It is provided to convert the main DC power source into motor drive voltage. 8 is a control device, and this control device 8 is for outputting a variable speed control signal for the motor 2, and is connected to the inverter. In addition, this] control device provides a DC/D
C: ] connected through a converter, this D C/D
The C converter 9 converts the main DC power source into a power source for driving the control device 8 . During normal operation, the drive power for the control device 8 itself is supplied from the power supply section 3, and when the main AC power supply is out of power, the regenerative T energy of the motor 2 is used to control the motor stop control I.
Continue outputting the jin sign to the inverter 7. A power failure detector 10 is provided to detect a power failure of the main AC power source and simultaneously output a stop command to the control device 8.

Next, the operation of the above embodiment will be explained.

First, during normal operation, main AC power is supplied to converter 4, which converts it into main DC power and outputs it to inverter 7 and DC/DC converter 9. The inverter 7 converts this main DC power into a motor drive voltage and supplies it to the motor 2. On the other hand, the DC/DC:1 inverter 9 steps down the main DC power and supplies it to the control device. The control device 8 is driven by the output of the DC/DC inverter 9 and outputs a variable speed control signal to the inverter 7. Drive and variable speed control of the motor 2 are performed by the above operations.

Next, the operation during a power outage will be explained. First, when a power outage occurs, the power supply to the converter 4 is turned off. At the same time, the power failure detector 10 outputs a power failure command to the control device @8. Control device 8 outputs a motor stop control signal to inverter 7 based on this command. The motor 2 enters a stop operation in response to this stop control signal, and at the same time, the motor 2 acts as a generator, and electric power is generated due to rotation due to its inertia, and a brake lock occurs. At the same time, the electric power is reversely converted by the inverter 7 and regenerated to the main DC power supply section 6. This regenerated energy is transferred to the control device via the DC/DC converter 9.
Drive 8. The control device N8 continues to output a motor stop control signal to the inverter 7 without stopping due to this regenerated energy. This action continues until the regeneration 1 energy of the motor 2 disappears, that is, the motor 2 completely stops.
It continues until I=.

Note that the DC/DC converter 9 is provided to step down the DC power supply to the drive voltage for the control device; however, in the case where the main DC power supply is used as the drive power supply as it is, this DC/DC converter 9 is Without setting:1:
The DC power supply unit 6 may be directly connected to the I/[1-L unit @8.

In addition, in the above embodiment, ] control equipment @8 is
An example has been described in which the control device 8 is connected to the main DC power supply unit 6 via the C/DC converter 9 and regeneration is performed to the main DC power supply unit 6, but as shown in FIG.
It may also be connected to the main AC power supply section 5 via the C/DC converter 11 to perform regeneration to the main AC power supply section 5 which is the preceding stage of the converter. In this case, the control device 8 (or AC/r to the main AC power supply section 5) C-+ converter 1
1, the same effect as in the previous embodiment is achieved. In addition, in this case, 0 of the power failure detector 10
It is preferable to operate a circuit breaker (not shown) installed at the connection with the three-phase bus line in synchronization with the movement of the three-phase bus line to prevent regenerated energy from entering the three-phase bus side.

Further, in each of the above embodiments, the motor is applied to a control device using a three-phase induction motor as an example of the motor, but the present invention is not limited to this. It may be applied. In the case of a DC motor, similar operational reliability can be achieved by using a DC/DC converter instead of the inverter as the converter in the above embodiment.

〔Effect of the invention〕

As described above, according to the present invention, even when power is generated due to a power outage, the stop control signal is continuously supplied to the converter as long as the motor is being driven. The signal is not interrupted, and stop control is reliably performed without the need for a mechanical braking mechanism or the like. In addition, unlike conventional dynamic braking systems, the generated energy is not consumed through resistance, so
11 The braking force does not decrease as the brake force decreases once.

Furthermore, since conventional control circuits can basically be used for the components in the 5A brake system of the present invention, it can be obtained extremely simply and at low cost without requiring any special equipment. .

In addition, when performing stop control in the event of a power outage, especially for induction motors that do not have magnets inside, conventionally it was necessary to rely on mechanical P7 friction brakes, but with the application of the present invention, This is an extremely effective control device that can reliably perform stop control in the event of a power outage without using a mechanical brake that interferes with the inherent features of the electric motor.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing an embodiment in which the entire control device of the present invention is applied to a control device for an induction motor, and FIG. 2 is a block circuit diagram showing another embodiment of the same. 1... Motor control device, 2... Motor, 3... Power supply unit, 4... Inverter, 5... Main AC power supply unit, 6... Main DC power supply unit, 7... Converter, 8... control device,
9...DC/DC converter, 11...AC/[)C converter.

Claims (6)

[Claims] (1) A power supply section having a converter for converting main AC power into main DC power; a converter connected to this power supply for converting the main DC power into motor drive voltage; and this converter. and a control device for outputting a motor control signal to the converter, wherein the control device outputs a motor stop control signal to the converter using regenerated energy of the motor during a power outage of the main AC power supply. 1. A motor control device, characterized in that the motor control device is connected to the power supply section for the purpose of controlling the power source. (2) The motor control device according to claim 1, wherein the motor is an induction motor and the converter is an inverter. (3) The motor control device according to claim 1, wherein the motor is a synchronous motor and the converter is an inverter. (4) The motor control device according to claim 1, wherein the motor is a DC motor and the converter is a DC/DC converter. (5) The motor control according to any one of claims 1 to 4, wherein the control device is connected to the main DC power supply section of the power supply section via a DC/DC converter. Device. (6) The motor control according to any one of claims 1 to 4, wherein the control device is connected to a main AC power supply section of the power supply section via an AC/DC converter. Device.