A Novel Method on Regenerating Control of Position Sensorless Brushless DC Motor

In order to simplify structure,lower cost and raise reliability of brushless DC motor(BLDCM) and to implement bidirectional transmission of electric energy between supply and armature windings,a novel method on regenerating control of position sensorless BLDCM is proposed in this paper.The method presents to detect three-phase terminal voltages and sense armature winding's currents via two-order RC analog filter and corresponding digital filter respectively.Thus,back EMFs without triple harmonics are calculated according to mathematical model of BLDCM.Furthermore,the rotating direction,speed and equipotential points are evaluated and the correct commutation instants and logic signals are determined.Finally,according to reversal principle of electric machines,a simple,reliable and uncontrollable rectifier which regenerates electric energy from BLDCM to high and/or low voltage batteries is also introduced in this paper.