Parameter and Speed Estimation for Implementing Low Speed Sensorless PMSM Drive System Based on an Algebraic Method

This paper presents a sensorless control scheme for a surface-mounted permanent-magnet synchronous machine (SM-PMSM) using the high frequency voltage signal injection method. The reactances of the high frequency model vary as a function of rotor position and a simple method based on measured high frequency currents and voltages is used to identify these reactances. Using such motor reactances, rotor position and velocity can be estimated. The proposed method is algebraic and does not require accurate knowledge of the initial value of the rotor position. The strategy was verified experimentally using a commercial SM-PMSM machine.