Patent ID: 8686672

Claim:
A motor control device for a motor, the motor control device comprising: a motor control signal generator configured to generate a motor control signal by executing current control in a d/q coordinate system; and a drive circuit configured to output three-phase drive power to the motor based on the motor control signal, wherein: based on a rotational angular velocity of the motor and a current command value in the d/q coordinate system, the motor control signal generator estimates an expected voltage utilization factor, which is the ratio of a required output voltage to a maximum voltage applicable to the drive circuit, and corrects the current command value such that the expected voltage utilization factor does not exceed a predetermined value that corresponds to a voltage saturation limit, the motor control signal generator computes a d-axis current command value to execute field weakening control such that the expected voltage utilization factor does not exceed the predetermined value, and when the expected voltage utilization factor exceeds a limit value in a range that can be dealt by the field weakening control, the motor control signal generator reduces a q-axis current command value, thereby correcting the current command value such that the expected voltage utilization factor does not exceed the predetermined value.