Motor control device

A motor control device, comprising:

• a rotational position detector for detecting a rotational position of a motor;
• an electric current detection unit for detecting at least two phase currents among three phase currents applied to the motor;
• a coordinate conversion unit for mutually converting values of said three phase currents on predetermined coordinates, and values on d-q coordinates being coordinates on a rotating magnetic field of the motor;
• an electric current control unit for generating voltage instruction-values being control inputs of voltages, based on a difference between electric current instruction-values being control inputs for said three phase currents, and electric current feedback values being currents detected by the electric current detection unit and d-q coordinate-converted by the coordinate conversion unit;
• an electric power converter for generating, based on said voltage instruction-values, three-phase voltages being inputted through the electric current detection unit so that predetermined electric power is supplied to the motor;
• an induced-voltage estimation unit for estimating, based on said voltage instruction-values and said electric current feedback values, an induced voltage of the motor;
• a dead-time disturbance-voltage compensation unit for generating a dead-time disturbance compensation-voltage being a voltage to compensate disturbance, with respect to an output produced at the electric current detection unit, due to dead time which is a short-circuit prevention period of two switching devices provided in the electric power converter;
• and
• a dead-time disturbance compensation-voltage modification unit for modifying said dead-time disturbance compensation-voltage in accordance with said electric current instruction-values, and also having the induced-voltage estimation unit, and, based on a fundamental wave component of an induced voltage being estimated, a dead-time disturbance compensation-voltage memory unit for calculating an error of said dead-time disturbance compensation-voltage and for storing the error inside, wherein
• the motor control device comprises two operation modes of a dead-time disturbance compensation-voltage adjustment mode for setting said electric current instruction-values in accordance with an operation pattern of the motor in order to acquire said dead-time disturbance compensation-voltage, and
• a torque-ripple suppression control mode for estimating torque of the motor, and for curbing a torque ripple thereof based on the torque being estimated;
• and,
• after operations in the dead-time disturbance compensation-voltage adjustment mode are completed, the operations transfer to the torque-ripple suppression control mode.