Low Speed Control Strategy for Sensorless Permanent Magnet Synchronous Motor Drives

In the traditional method of high frequency voltage injection, a large number of filters are required for noise removal in order to get the desired current signal, but this results in a phase shift in the system, leading to errors in the position estimation. To address this phenomenon, this paper proposes a strategy which use high frequency injection based on improved the second-order generalized integrator. Firstly, double second-order generalized integrator is used to replace the filter in the speed-ring. Secondly, proposing an improved second-order generalized integrator by adding a higher-order Butterworth pass filter loop to improve its dynamic performance. Finally, a simulation model is built in Simulink and validated on an experimental platform to determine the results of the proposed method. And they show that the method resides in better dynamic performance and anti-harmonic noise capability compared to the traditional method.