Position Sensorless Algorithm for IPMSM Based on Extended Electromotive Force

A position sensorless algorithm based on extended electromotive force (EEMF) is proposed to address the issues of inconsistent models and complex switching algorithms in the traditional low speed and high speed position sensorless control of IPMSM. In the low speed range, signal injection is employed to enhance the amplitude of EEMF. Conversely, in the high speed range, the signal injection is halted, ensuring a sustained high signal to noise ratio for EEMF throughout the start up and medium to high speed ranges. A synchronous axis moving average filter is designed to effectively suppress harmonics in EEMF. Additionally, a position error fusion algorithm is proposed to avoid speed fluctuations caused by the switching of position error information. Simulation results demonstrate that the algorithm exhibits small position observation errors and speed fluctuations within the rated speed range, validating the feasibility of the proposed approach.