Sensorless control of permanent magnet synchronous motors for wide speed range applications

This paper deals with sensorless control of interior permanent magnet synchronous motors (IPMS) based on the estimation of speed and rotor angular position. The above estimate is based on the injection of high frequency stator currents able to generate a signal similar to that generated by a resolver connected to the axis of the motor. A new digital algorithm has been designed to demodulate the above signal whose implementation can be carried out on the same DSP that processes the control algorithm. In this paper a new scheme of speed and angular position estimator is proposed and justified on the theoretic point of view. The experimental results here shown validate the effectiveness of the sensorless control algorithm in all the operating situations concerning the whole speed and load torque ranges