Abstract text

An inverter device driving an induction motor including main and auxiliary windings both having different winding specifications includes 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 PWM voltage, a current detector detecting currents of the respective main and auxiliary windings from a DC power supply current, a vector control computing unit obtaining 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 forming a PWM signal controlling the inverter circuit according to the two-phase voltage.