Sensorless control of an interior permanent magnet synchronous motor on the rotating coordinate using an extended electromotive force

Permanent magnet synchronous motors have been widely used in industrial applications for their high efficiency. To control permanent magnet synchronous motors, knowledge of rotor position and velocity is necessary. However, position sensors are expensive and mechanically bulky. Although many sensorless control methods have been proposed, but these schemes used approximations for simplification of the mathematical model, which may lead to unstable problems at certain conditions. To solve this problem, the sensorless control based on an extended electromotive force model has been proposed in this paper. The proposed method has been verified by experiments.