Inverter apparatus for supplying drive power to an electric motor, and filter apparatus for use in the inverter apparatus

摘要

A filter apparatus (8) has a current-detecting coil (L3). The coil detects a high-frequency leak current (I1) flowing from the phase-windings (123r, 123s, 123t) of a motor (120) to the earth terminal (E) through the closed case (111) of a compressor (101). A current-canceling circuit (30) generates a current (I2) similar in waveform to the high-frequency leak current (I1) detected by the coil (L3). The current thus generated cancels out the high-frequency leak current (I1). <IMAGE>