JP2001128486A - Control device of motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to equipment where a motor is incorporated, and generation of an accident resulting in injury, death, or the like, even when an AC power failure detection circuit malfunctions. SOLUTION: The control device is equipped with a an AC power failure detection circuit 14 for detecting the break of the power supply, and a motor voltage detection circuit 15 for detecting voltage being applied to the motor 2, when a high-voltage power supply being applied to a motor 2 is broken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a motor driven by a battery when a normal power supply is cut off due to a power failure or the like.

[0002]

2. Description of the Related Art An automatic door is an example of a device that requires a motor driven by a battery when a normal power supply is cut off due to a power failure or the like. For safety reasons, this automatic door needs to open and close to some extent even during a power failure. Therefore, it is necessary to supply a voltage to the motor by a battery or the like.

A conventional control device for a motor driven by a battery during a power failure will be described with reference to FIG. 2 taking a control device for a brushless DC motor as an example. FIG. 2 is a block diagram of a conventional motor control device.

In FIG. 2, when a commercial power supply voltage of AC 100 V (or AC 200 V) is supplied to a control device 21, first, a control voltage for controlling an electronic circuit and a motor voltage used for driving the motor 2 are determined. Is branched to

The control voltage supplied to the electronic circuit is stepped down by a transformer 3 and converted to a direct current by a rectifying / smoothing circuit 4 to provide a DC power supply voltage for an electronic circuit (5 V to 12 V).
V) and supplied to each electronic circuit.

On the other hand, a motor voltage supplied for driving the motor 2 is converted into a direct current by a rectifying / smoothing circuit 5 and supplied to the motor 2 via an inverter circuit 6.

A logic circuit 7 receives a signal from a position sensor 8 (PS) mounted inside the motor 2 and controls the inverter circuit 6 based on this signal so that the motor 2 rotates properly. are doing.

When performing speed control, first, a pulse signal output from the position sensor 8 and proportional to the rotation speed of the motor 2 is converted into a voltage by the F / V conversion circuit 9. Then, the converted voltage is input to the speed control circuit 10,
PWM is generated by a square wave PWM circuit 12 based on the speed command from the interface circuit 11. This PWM
Is input to the inverter circuit 6 via the logic circuit 7,
The voltage value applied to the motor 2 is adjusted to control the rotation speed of the motor 2.

The operation sequence control circuit 13 includes the motor 2
A circuit for instructing an operation pattern such as a rotation speed and a rotation direction of the motor 2, and controls an operation pattern of the motor 2 via an interface circuit 11.

When a power failure occurs, the commercial power supply voltage supplied to the control unit 21 is cut off.
V). The AC power failure detection circuit 14 detects that the power supply voltage has been cut off, and outputs this detection signal to the interface circuit 11. The interface circuit 11 issues a command to the logic circuit 7 based on the command from the operation sequence control circuit 13 so that the motor 2 rotates properly at the time of power failure. Normally, the power supply voltage of the battery is lower than the commercial power supply voltage,
The motor 2 is controlled by the maximum voltage of the battery.

[0011]

In the case where a motor normally driven by a high-voltage power supply of 100 V or 200 V needs to be driven by a low-voltage power supply such as a battery during a power failure, as in the conventional example, As described above, an AC power failure detection circuit is required.

However, during normal operation, if the AC power failure detection circuit operates due to a malfunction of the AC power failure detection circuit despite the fact that a high voltage is actually applied to the motor, that is, the AC power failure detection circuit makes a mistake in determining that a power failure has occurred. Therefore, the maximum voltage may be applied to the motor. Therefore, there is a risk that the motor will be operated at a speed exceeding the normal rated speed, and that the device incorporating the motor will be damaged, or a personal injury or the like will occur.

[0013]

Therefore, according to the present invention, when a high-voltage power supply to a motor is cut off, an AC power failure detection circuit for detecting the cut-off of the power supply and a voltage applied to the motor are detected. A motor control device, comprising: a motor voltage detection circuit.

[0014]

The motor voltage detection circuit detects the voltage actually applied to the motor even when it is driven by a low-voltage power supply such as a battery at the time of a power failure.
The actual control state of the motor is detected and fed back to the speed control circuit to control the motor so as not to generate an abnormal output.

Therefore, even if a malfunction occurs in the AC power failure detection circuit, the device incorporating the motor may be damaged,
Also, there is no occurrence of personal injury or the like.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described using a control device for a brushless DC motor. FIG. 1 is a block diagram of a control circuit according to the present invention.

In FIG. 1, a motor control device 1 has a circuit configuration similar to a control device 21 in a conventional example. Further, between the rectifying and smoothing circuit 5 and the inverter circuit 6, a motor voltage detecting circuit 15 is added. The motor voltage detection circuit 15 can always detect the voltage applied to the motor 2, and inputs the detected information to the speed control circuit 10.

When a power failure occurs, the power supply voltage supplied to the control device 1 is cut off, and the control device 1 is driven by the voltage of the battery. Therefore, the voltage applied to the inverter circuit 6 is low. The motor voltage detection circuit 15 inputs this voltage value to the speed control circuit 10. Further, the AC power failure output circuit 14 transmits information of the power supply voltage being cut off to the operation sequence control circuit 13 via the interface circuit. Then, the operation sequence control circuit 13 instructs the speed control circuit 10 via the interface circuit 11 so that the motor 2 rotates properly at the time of power failure, that is, applies the maximum voltage to the motor 2. Put out. After confirming that the voltage applied to the motor 2 is low, the speed control circuit 10 performs control during a power failure.

When the AC power failure output circuit 14 malfunctions, the voltage applied to the inverter circuit 6 is in a normal high voltage state.
To enter. Further, even if the AC power failure output circuit 14 malfunctions and issues a command from the interface circuit 11 to the speed control circuit 10 to apply the maximum voltage to the motor, the speed control circuit 10 In order to prevent the motor 2 from exceeding an abnormal rotation speed such that the motor 2 exceeds the rated rotation speed,
Control to suppress the voltage applied to the motor.

As described above, by configuring the controller 1, even if the AC power failure detection circuit 14 malfunctions, the motor voltage detection circuit 15 always detects the motor voltage. This can prevent the damaged equipment or the occurrence of personal injury or the like.

[0021]

According to the present invention, even if the AC power failure detection circuit malfunctions, it is possible to prevent damage to equipment in which the motor is incorporated, or to prevent the occurrence of personal injury or the like.

[0022]

[Brief description of the drawings]

FIG. 1 is a block diagram of a control circuit according to the present invention.

FIG. 2 is a block diagram of a conventional motor control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 21 ... Control device 2 ... Motor 3 ... Transformer 4, 5 ... Rectifier smoothing circuit 6 ... Inverter circuit 7 ... Logic circuit 8 ... Position sensor 9 ... F / V conversion circuit 10 ... Speed control circuit 11 ... Interface circuit 12 ... Square Wave PWM circuit 13: Operation sequence control circuit 14: AC power failure detection circuit

Claims (1)

[Claims] 1. A motor control device which is normally driven by a high-voltage power supply and switches to a low-voltage power supply such as a battery when the high-voltage power supply is cut off. A motor control device, comprising: an AC power failure detection circuit that detects the interruption of the power supply when the power supply is interrupted; and a motor voltage detection circuit that detects a voltage applied to the motor.