Improvement of Detecting for Rotor Position of BLDCM Based on Back-EMF Method

For the detection of zero crossing point(ZCP)of back-electromotive force(EMF)which is most widely applied in detecting for rotor position of the brushless DC motor(BLDCM),the shortage of 90 electrical angle phase filter was discussed.A method without depth filtering was proposed.Software algorithm filtered the interference signal from commutation in this method.It can widen the speed control range and reduce the torque ripples which were brought by the inaccurate of commutation point.Experiments prove the effectiveness and validity of this method.