JPH07163043A - Motor controller - Google Patents

Abstract

PURPOSE:To provide a motor control with simple constitution by using a relatively small control current. CONSTITUTION:In a motor controller, a motor lock state is detected on the basis of signals from three Hall elements 2, 3, and 4 that are mounted on each three-phase winding of the motor to detect the revolutions of the motor. Then, the detection signals Hu, Hv, and Hw generated from the Hall element 2, 3 or 4 are entered in a logical element like an AND circuit 5. If one or more of detection signals Hu, Hv, and Hw are not entered for a given time into the AND circuit 5, a condition that the motor is locked is judged so that a forced motor stopping signal is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for protecting a motor by detecting a locked state of the motor.

[0002]

2. Description of the Related Art If a motor locks due to overload, an excessive current flows through the motor, which is dangerous. Therefore, in order to improve the safety in use of the motor, the motor control device that controls the rotation speed of the motor has a motor lock detection function. This motor lock detection function detects the current value of the drive signal supplied from the control device to the winding of the motor, and when this current value exceeds a predetermined reference value, it is determined that the motor is in a locked state, The rotation of the motor is stopped.

[0003]

In such a conventional motor lock detecting function, since the lock state is detected by detecting the value of the current flowing through the winding of the motor, a relatively large current is detected. Need to handle. Therefore, there is a problem that the circuit configuration becomes complicated.

An object of the present invention is to solve the above technical problems and to provide a motor control device capable of simplifying the structure by handling a relatively small current.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a rotation provided in a motor which is rotationally driven based on an input control signal, and which outputs a pulse signal corresponding to the rotation of the motor to detect the number of rotations of the motor. Number detection element, a pulse detection means for detecting whether the pulse signal from the rotation speed detection element is output over a predetermined period, and the pulse detection means, the pulse signal over the predetermined period. The motor control device includes a signal output stopping unit that determines that the motor is in a locked state and stops outputting the control signal to the motor when it is detected that the rotation speed detection element is not outputting the signal.

[0006]

According to the present invention, the number of rotations of the motor which is rotationally driven based on the input control signal is detected by the number-of-rotations detecting element which is provided in the motor and outputs a pulse signal corresponding to the rotation of the motor. To be done. The pulse detection means detects whether or not the pulse signal from the rotation speed detection element is output for a predetermined period. On the other hand, when the pulse detection means detects that the pulse signal is not output from the rotation speed detection element for the predetermined period, the signal output stop means determines that the motor is in a locked state and the motor is stopped. To stop the output of control signals to.

As a result, a relatively small signal current from the rotation speed detecting means is handled, and the configuration of the motor control device can be simplified.

[0008]

FIG. 1 is a block diagram showing the basic construction of the present invention. In the following description, a three-phase AC drive motor will be described, but the present invention is not limited to the type of motor. The motor lock detection function in the motor control device 1 of the present invention is provided in the motor, and three hole elements 2 are provided as an example corresponding to the three-phase winding of the motor for detecting the number of rotations of the motor. It is performed based on the signals from 3, 4. Detection signal H from each hall element 2, 3, 4
When u, Hv, and Hw are input to a logic element such as the AND circuit 5 as an example, and even if any one of the detection signals Hu, Hv, and Hw is not input to the AND circuit 5 for a predetermined period, it is determined that the motor is in a locked state. Then, the motor forced stop signal is output.

FIG. 2 is a block diagram showing a configuration example of the motor control device 1 according to one embodiment of the present invention, and FIG. 3 is a time chart for explaining the operation of the motor control device 1. In this embodiment, a three-phase AC drive motor (hereinafter, motor) 6
Is used. An inverter circuit 7 that outputs a drive signal for driving the motor 6 is connected to the motor 6, and the motor 6 detects changes in the magnetic poles for each phase of the motor 6 and responds to the changes in the magnetic poles. The three hall elements 2, 3 and 4 for outputting pulsed detection signals are arranged. Detection signals Hu, H from the respective hall elements 2, 3, 4
v and Hw are input to the processing circuits 8, 9, and 10, respectively. The processing circuits 8, 9 and 10 have detection signals Hu and H, respectively.
It is detected whether v and Hw have been input for a predetermined period such as a two-pulse cycle as an example. This predetermined period is determined as a time constant determined by the capacitance C1 and the resistor R1 externally attached to each processing circuit 8.9.10.

The outputs of the processing circuits 8, 9 and 10 are ANDed.
It is input to the circuit 5. The output of the AND circuit 5 is three A's.
It is commonly input to the ND circuits 11, 12, and 13. Each AN
The D circuits 11, 12 and 13 have respective hall elements 2, 3, 4 respectively.
The detection signals Hu, Hv, Hw from are respectively input. The outputs of the AND circuits 11, 12, 13 are input to the inverter circuit 7. On the other hand, a speed command signal for setting the motor 6 at a predetermined rotation speed is output from the signal source 14 and input to the collector of the transistor 16. The emitter of the transistor 16 is connected to the ground potential as an example. The AND circuit 5 is connected to the base of the transistor 16.
The output of is inverted by the inverting circuit 15 and the inverted signal is input.

As shown in FIGS. 3A and 3B, as an example, if the detection signal Hu is output without missing a pulse, the output from each processing circuit 8, 9, 10 will be described. Is a high level. As a result, the AND circuit 5
Output becomes high level, and each AND circuit 11, 12,
A signal obtained by modulating the detection signals Hu, Hv, and Hw with the speed command signal is output to the inverter circuit 7 via 13.

On the other hand, as shown in FIGS. 3 (3) and 3 (4), for example, when the detection signal Hu has a missing pulse of one pulse or more, the output from the corresponding processing circuit 8 is low. It becomes a level. As a result, the output of the AND circuit 5 becomes low level, and the AND circuits 11, 12, 13
Is cut off. As a result, the motor 6 is forcibly stopped.

Thus, in this embodiment, each ho
Since the lock detection of the motor 6 is performed by using the signals of small current values such as the detection signals Hu, Hv, Hw from the control elements 2, 3, 4, the configuration for detecting the lock of the motor 6 can be simplified. it can.

[0014]

As described above, according to the present invention, the number of rotations of the motor rotationally driven based on the input control signal is provided in the motor and a pulse signal corresponding to the rotation of the motor is output. It is detected by the rotation speed detecting element.
The pulse detection means detects whether or not the pulse signal from the rotation speed detection element is output for a predetermined period. On the other hand, when the pulse detection means detects that the pulse signal is not output from the rotation speed detection element for the predetermined period, the signal output stop means determines that the motor is in the locked state and the motor is stopped. To stop the output of control signals to.

As a result, a relatively small signal current from the rotation speed detecting means is handled, and the structure of the motor control device can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention.

FIG. 2 is a block diagram showing a configuration example of a motor control device 1 according to an embodiment of the present invention.

FIG. 3 is a time chart explaining the operation of the motor control device 1.

[Explanation of symbols]

 1 Motor control device 2, 3, 4 Hall element 5, 11, 12, 13 AND circuit 8, 9, 10 Processing circuit

Claims (1)

[Claims] 1. A rotation speed detection element, which is provided in a motor driven to rotate based on an input control signal, outputs a pulse signal corresponding to the rotation of the motor to detect the rotation speed of the motor, and a predetermined period. Pulse detection means for detecting whether or not the pulse signal from the rotation speed detection element is output, and the pulse detection means outputs the pulse signal from the rotation speed detection element for the predetermined period. A motor control device comprising: a signal output stop means for determining that the motor is in a locked state and stopping output of a control signal to the motor when it is detected that the motor is not present.