Influence of Input-Voltage Waveform on Current-Torque Ratio of Brushless DC Motors

Abstract

This paper analyzes the influence of input-voltage waveform on the performance of a three-phase brushless DC (BLDC) motor. The six-step control and the V/Hz control are used in the analysis with focus on time harmonics. The solution shows how to use higher time harmonics in the supply voltage to increase the current-torque ratio of BLDC motors. The simulation is made for both delta- and star-connected BLDC motors with high harmonic distortion of its back electromotive force (BEMF). The theoretical results are compared with experimental measurements.