Patent ID: 8102141

Claim:
An inverter device which drives an induction motor including a main winding and an auxiliary winding both having different winding specifications, the inverter device comprising: a three-arm inverter circuit having phase output terminals connected to the main winding, the auxiliary winding and a neutral winding of the induction motor respectively and converting a DC power supply to two-phase substantially sinusoidal pulse width modulation (PWM) voltage; a current detector which detects currents of the respective main and auxiliary windings from a DC power supply current; a vector control computing unit which obtains balanced inductance values and resistance values from inductance values and resistance values of the respective main and auxiliary windings, determining a two-phase voltage to be supplied to the induction motor by vector control computing based on the balanced inductance values and resistance values; and a PWM signal forming unit which forms a PWM signal controlling the inverter circuit according to the two-phase voltage.