Pulse width modulation (PWM) of voltage source inverter (VSI) is common for speed regulation of permanent magnet (PM) brushless direct-current (BLDC) motor drives. However, when the motor runs at high speed, the
conventional PWM technique may become unfeasible due to the low carrier ratio of inverter, which makes the motor current distorted and the motor core loss increased significantly. In this paper, two control strategies,
namely single pulse variable width (SPVW) and dual pulses variable width (DPVW), are introduced for the high-speed PM BLDC motor drives, and are comprehensively investigated. Finite element method (FEM) is
employed to evaluate and compare the drive system performance when using the conventional PWM, and the proposed SPVW and DPVW, respectively. Influence of the control techniques, especially on the loss distribution, is revealed.