Review of position estimation methods for PMSM drives without a position sensor, part III: Methods based on saliency and signal injection

This paper presents a review in state of the art techniques for position sensorless permanent magnet synchronous motor (PMSM) drives. In particular estimator based on methods using injected rotating or alternating carrier signals, methods based on monitoring the space vector of the stator currents and methods based on inductance variations, like INFORM are presented. Furthermore the authors give an overview for magnetization polarity detection, which is necessary for starting strategies respectively initial position detection.