A Rotor Initial Position Estimation Method for Surface-Mounted Permanent Magnet Synchronous Machine

A new rotor initial position estimation method for surface-mounted permanent magnet synchronous machines (SPMSM) is presented in this paper. The proposed method is based on the magnetic saturation effect and is suitable to prevent starting failure and reverse rotation. Compared with conventional methods, the proposed method shows better effective estimation performance. New strategies for utilizing current responses and voltage pulse injection process are developed. As a result, only three pulses are needed in total at no cost of extra sensors, while maintaining at least 30-degree estimation resolution at the same time. Moreover, a boundary detection strategy (BDS) is proposed to enhance the estimation performance regarding the impact of current measurement noises. Further, based on the BDS, a concept of 'boundary width' is proposed. By properly selecting the boundary width, the estimation resolution can be improved from 30 degrees to 15 degrees. Experimental results are given to verify the effectiveness of the proposed method.