Rotor position estimation method of permanent magnet synchronous motor with absolute position calculation and simple deviation compensation strategies

High-frequency signal injected methods are widely applied to the sensorless control of permanent magnet synchronous motor (PMSM) especially at standstill and low-speed range. Most of the methods are based on the tracking theory, which leads to an angle uncertain of π. The method proposed in this Letter is also based on the injection method and can calculate the rotor absolute position directly by introducing a virtual reference frame which rotates at a fixed frequency, which makes it possible to eliminate the angle uncertain of π with a simple deviation compensation method. Furthermore, all the PMSMs even with near-zero saliency can adopt the proposed method. Finally, the simulation results show that the proposed rotor position estimation method has a good performance even under load changes.