Saliency based encoderless predictive torque control without signal injection

This paper presents a basic scheme for rotor position estimation of salient synchronous machines by utilizing internal information of a predictive torque controller. Although the proposed estimation scheme is based on a rotor saliency and thereby capable of permanent operation at standstill, this method has no need for the injection of an additional voltage which extends the feasible operation region to the whole speed range of the drive. Thus the proposed method overcomes the main drawback of HF injection methods while keeping its advantages. The proposed scheme is derived mathematically for a salient permanent magnet synchronous machine and verified in simulation.