Estimate of rotor position of BDCM based on the third harmonic component

A rotor position estimation method is presented based on the 3/sup rd/ harmonic component detection in BDCM (Brushless DC Motor). An imitated phase voltage and a digital phase locked loop are adopted to ensure the real rotor position tracking precisely. The whole system is simpler and more reliable in the proposed method than that in the traditional method. The analysis of the 3/sup rd/ harmonic sensing method is performed in the paper. The experimental results are demonstrated to verify the validity of the proposed method.