Motor speed controller

Abstract

A motor speed controller detects out-of-control reverse rotation of a motor even when the pulse signal obtained from the motor and synchronized with the rotation is of only one kind. A target instruction signal is generated on the basis of a target rotational speed [omega]T of the motor. A compensation instruction signal is generated on the basis of an error signal Ve that corresponds to a difference between the actual rotational speed [omega] and [omega]T. A composite signal is generated by combining above two instruction signals. A state in which the control direction of the composite signal with respect to [omega] is the reverse of the direction of [omega]T, and the strength of the composite signal exceeds a designated threshold continues for a designated period, is judged as a state of out-of-control reverse rotation, and restoration to the normal state is performed.

Description

technical field [0001] The present invention relates to a motor speed control device that uses feedback control to control the rotational speed of a motor. Background technique [0002] The motor speed can be controlled by obtaining a pulse signal PI whose period varies according to the rotation speed ω of the motor from the motor module. The motor speed control device measures the pulse period τ occurring in this pulse signal P , and detect the rotation speed ω of the motor according to its period, so as to perform feedback control so that the rotation speed ω becomes the target value ω T . [0003] If two types of pulse signals PI generated synchronously at rotational positions different from each other by, for example, 90° can be obtained from the electric motor, the rotational direction of the electric motor can be discriminated in the motor speed control device. [0004] Patent Document 1: Japanese Unexamined Patent Publication No. 8-126374 [0005] However, when on...

AI Technical Summary

Problems solved by technology

[0005] However, when only one kind of pulse signal PI can be obtained from the motor, even if the magnitude of the rotation speed can be detected from the pulse period τP, the direction of the rotation speed cannot be distinguished.

Therefore, for example, there is a problem that if an error occurs in the measurement value of the pulse period τP due to chattering or the like generated in the pulse signal PI, the control to the target rotation speed may be lost, and the motor may be driven to reverse and run out of control.

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