Sensorless control of PMSM drives using a combination of voltage model and HF signal injection

This paper presents a method for the rotor speed and position estimation of permanent magnet synchronous motors in a wide speed range including standstill. The proposed method is based on a modified voltage model at high speeds, and combines the modified voltage model with a high-frequency signal injection technique at low speeds. The fast dynamic response of the voltage model is thus augmented with the steady-state accuracy of the high-frequency signal injection technique. The stability and robustness of the combined observer are confirmed by simulations and experiments.