Motor driving apparatus

Abstract

The invention suppresses the degradation of an input power factor or drive efficiency which is caused by the distortion of a current waveform flowing to a single-phase AC power source under the effect of a regenerative current from a motor 2 or a charging current to internal parasitic capacitance, related to a motor driver 101b of inverter driving that comprises no large capacitance capacitor.The motor driver comprises a single-phase rectification circuit 3 connected to a single-phase AC power source 1, an inverter circuit 4 which is connected to the single-phase rectification circuit 3 and applies a current and a voltage to a motor 2, and an inverter control unit 5b that controls the inverter circuit 4. The inverter control unit 5b controls the current supplied to a motor 2 which is the output of the inverter circuit 4, so that an inverter input voltage Vpn comes to be equal to an absolute value 3 / 4 v 3 / 4 of the voltage of the single-phase AC power source 1.

Description

technical field [0001] The present invention relates to a motor drive device, in particular to a motor drive device that drives a motor through a system composed of a single-phase rectifier circuit and an inverter. Background technique [0002] Conventionally used existing motor drive devices are devices that drive a motor through a system composed of a single-phase rectifier circuit and an inverter. Here, the single-phase rectification circuit has a reactor (not shown) for improving a power factor and a smoothing capacitor for smoothing an output voltage of the circuit. [0003] In such a conventional motor drive device, large-capacity elements are used for the smoothing capacitor and the reactor for improving the power factor, and there are problems in cost, life, efficiency, weight, size, etc. of the motor drive device. The purpose of using large-capacity components for smoothing capacitors and power factor-improving reactors is to avoid deterioration of the power factor...

AI Technical Summary

Problems solved by technology

Since the current that generates this regenerative power brakes the motor, the drive efficiency of the motor is reduced.

In addition, during this regeneration period, since no current is supplied from the single-phase AC power supply to the converter circuit, the current waveform of the single-phase AC power supply is deformed, and there is a problem that the input power factor of the converter circuit is lowered.