| 摘要 |
Provided are, a converter section (30) which converts a commercial AC voltage (VAC) into a DC voltage (VDC); an inverter section (60) which converts the DC voltage (VDC) into an output AC voltage (VOUT) of a predetermined frequency by a pulse-width modulation system based on an assigned PWM width, and supplies the output AC voltage (VOUT) to a compressor motor (70). Further, an instantaneous DC voltage detecting section (50) detects an instantaneous DC voltage (VDCS); and an arithmetic processing section (100) corrects the PWM width so as to maintain the output AC voltage (VOUT) at a desired value following the variation in the instantaneous DC voltage (VDCS). It is possible to operate a compressor motor (70) in an optimum state of load characteristics and efficiency. <IMAGE> |
