Patent ID: 8310183

Claim:
A motor control device comprising: a power convertor which applies an AC voltage command based on voltage commands on d and q axes to a permanent magnet motor under PWM control, the d axis representing a direction of a magnetic flux of the permanent magnet motor, the q axis being orthogonal to the d axis; a current detector which detects a motor current flowing through the permanent magnet motor, in synchronization with a period of the PWM control; a current profile generator which generates a current profile; a pilot voltage operator which calculates a pilot pulse voltage, on the basis of the current profile, and adds the calculated pilot pulse voltage to the voltage command on the d axis; a magnetic pole position detector which detects a position of a magnetic pole in the permanent magnet motor, on the basis of both the motor current and the pilot pulse voltage; a polarity identification evaluation current operator which calculates a polarity identification evaluation current to be used to identify a polarity of the magnetic pole in the permanent magnet motor, on the basis of a current on the d axis in the motor current; and a polarity detector which identifies a polarity of the magnetic pole, on the basis of a deviation between the polarity identification evaluation current and the current profile, and outputs a phase correction amount.