Design and Evaluation of PI Controller for Four Switch BLDC Motor Drive

Abstract

This article presents a comprehensive study on implementing four switch brushless DC (BLDC) motor drive for variable speed applications with PI controller. In this system, four switches are used in the commutation circuit to lower cost and improve performance. The reduction in the number of power semiconductor switches leads to reduction of losses and the control circuit. The principle of operation, switching sequence formulation for the four switch BLDC motor drive is presented. A PI controller is designed for speed control and evaluated by simulation for performance under various speed and load conditions. The designed closed loop controlled BLDC motor drive shows satisfying performance despite the reduction of switch count. The steady state error of the system is limited within 1% while improving the transient performance.