ELECTRIC MOTOR DRIVING DEVICE, AND COMPRESSOR DRIVING DEVICE

摘要

A motor driver is provided with a small capacitance capacitor for smoothing a DC voltage after rectification of the AC source or provided with no such capacitor so as to be of small size, light weight and low cost, and capable of effectively reducing a harmonic current of an input current, and a compressor drive having the motor installed therein is provided. The motor driver includes a rectifying unit (3) for rectifying an AC voltage from an AC source into the DC voltage, an inverter main circuit portion (6) for converting the DC voltage output from the rectifying unit (3) into the AC voltage so as to be applied to the motor (5), and a control unit (10) for controlling the voltage applied to the motor (5) from the inverter main circuit portion (6). The control unit (10) includes an output voltage limit unit (23) which limits a scalar value of the voltage applied to the motor (5) to be equal to or lower than a maximum output voltage defined by the DC voltage output from the rectifying unit (3). The voltage amount limited by the output voltage limit unit (23) is fed back to the control unit (10).