Novel phase advance method of BLDC motors for wide range speed operations

This paper proposes a novel phase advance method of brushless DC motors (BLDCMs) for wide range speed operations. In order to extend the speed of BLDCMs, it is necessary to control phase currents to lead the phase back EMF by a phase advance method. Many phase advance methods have been studied for the speed expansion of the BLDCM during the last 20 years. However, these conventional methods increase the torque ripple even if it widens the range of speed for the BLDCM. As compared with the conventional method, the proposed method takes definite advantages. it can obtain wider range speed and lower torque ripple. A key of this method is to broaden conduction area of phase currents by using an advance angle. The usefulness of the proposed phase advance method is verified through simulation results.