Controller for PWM/PAM motor

Abstract

It has been a subject to be able to control a motor driving unit which is controlled by switching to / from PWM control from / to PAM control so that the maximum limit of the revolution per minute can be increased and, at the same time, the unit can be operated at the maximum efficiency in a steady-state operation. The above problem can be solved by a control means for a motor which comprises a converter circuit, an inverter circuit connected to the output of the converter circuit, amotor connected to the inverter circuit, and a speed control signal computing means that outputs a DC voltage command and a conduction ratio command to the converter control circuit and the inverter control circuit; wherein the speed of the motor is controlled by maintaining the DC voltage command to the converter control circuit constant but altering the conduction ratio command value to the inverter control circuit when the load to the motor is low, and by maintaining the conduction ratio command to the inverter control circuit constant but altering the DC voltage command to the converter control circuit; and said control means comprises a commutating phase control means that alters the commutating timing of the coil of the motor, and the motor is so controlled that the efficiency becomes the maximum limit in a steady-state operation and the revolution per minute becomes the maximum limit in a high-speed operation.

Description

technical field [0001] The present invention relates to a motor control device, and a control method of the motor, which can control the speed of the motor to reach the required revolutions per minute (r.p.m), and simultaneously control the input sinusoidal current to improve power factor and suppress Distortion of harmonic currents, and also relates to an air conditioner or refrigerator using the motor control device to drive a compressor drive motor and regulate room air. Background technique [0002] The control method described in Japanese Patent Application Laid-Open Publication No. SHO 63-224698 (1988) is a common method of a motor control device located in a rectifier circuit that rectifies alternating current and converts it into direct current power, which The speed of the motor is controlled by a combination of a power supply circuit that controls the DC voltage and a motor drive circuit. This method controls the motor speed by PWM (Pulse Width Modulation) control...

AI Technical Summary

Problems solved by technology

However, insufficient consideration has been given to the working efficiency of the motor under PWM control

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