Patent ID: 6940249

Claim:
An inverter device comprising: a power rectification circuit for converting alternating current power into direct current power; an inverse transformation control circuit connected to a direct current output terminal of said power rectification circuit for converting the converted direct current power into alternating current power; an output transformer for raising voltage interposed between an alternating current output terminal of the inverse transformation control circuit and an alternating current synchronous motor; a PWM control circuit for PWM controlling said inverse transformation control circuit according to a current command value generated by comparing a speed reference signal with a speed feedback signal of said alternating current synchronous motor; a bypass circuit for switching so as to bypass said transformer when the motor is started and to pass said transformer at a predetermined time after starting of the motor; and a maximum voltage limit value switch for limiting a maximum output voltage of said inverse transformation control circuit to a value at which a given low voltaae start is enabled at the time of the bypassing operation and to a value at which a given high voltage start is enabled at the time of the passing operation.