Evaluation of methods for the operation of PMSM without position sensor

This paper presents an analytical evaluation of sensorless methods for the operation of permanent magnet synchronous machines. The influence of position estimation errors on the stability of a current controller and the deviation of the actual current value from the reference current are considered. Taking these effects into consideration, a flux estimator and a signal injection method are analyzed. Accuracy estimations and design guidelines for the implementation of the two methods are given.