The improved EKF velocity estimation algorithm for PMSM and experimental assessment

This paper presents the improved EKF rotor velocity estimation algorithm for the PMSM servo system with an incremental optical encoder in detail. In a common PMSM servo system, the velocity got by the fixed-time method always carries quantization noise in the form of random impulse due to the quantization error of the encoder. The traditional method treats the quantization error as high frequency noise, and uses a first-order low-pass filter to eliminate it, but it would bring lagging and attenuation. While the proposed improved EKF velocity estimation algorithm can overcome the defects mentioned above to estimate the velocity precisely, besides no circuit modify and no matrix calculation are need. Finally serial experiments are carried out to evaluate its performance and practicality.