Motor controller, motor system and method for controlling motor

Abstract

A motor controller includes an observer that estimates a y-axis electromotive force and a δ-axis electromotive force, during an idle time of a rotor of a motor. The motor controller includes a derivation unit that derives a phase difference between dq axes and yδ axes, from the y-axis electromotive force and the δ-axis electromotive force. The motor controller includes an estimation unit that estimates an idling state of the rotor from the phase difference. For example, the estimation unit estimates an idle velocity of the rotor from periodicity of the phase difference. For example, the estimation unit estimates a pole position of the rotor during the idle time, from the phase difference, a sign of the y-axis electromotive force, and a sign of the δ-axis electromotive force.

Dependencies are inferred from the claim text.