Patent ID: 8497645

Claim:
A control device for controlling an electric motor drive device including an inverter that converts a DC voltage to an AC voltage to supply the AC voltage to an AC electric motor, comprising: a current control portion for performing a current control process of determining a voltage command value based on a deviation between a current command value, which is a command value of a current to be applied to a coil of the AC electric motor, and a current detection value, which is a detection value of a current that flows in the coil; a voltage control portion for performing a voltage control process of generating a switching control signal of the inverter corresponding to the voltage command value; a current control period determining portion for determining a current control period, which is a period of performing the current control process, based on target torque of the AC electric motor; a voltage control period determining portion for determining a voltage control period, which is a period of performing the voltage control process, based on a rotating speed of the AC electric motor; and a control period setting portion for setting the current control period and the voltage control period based on the determination of the current control period determining portion and the voltage control period determining portion, wherein the current control period determining portion determines, according to the target torque, the current control period as a value that increases continuously or stepwise as the target torque decreases, and the voltage control period determining portion determines, according to the rotating speed, the voltage control period as a value that increases continuously or stepwise as the rotating speed decreases.