Design and simulation of sensorless BLDC motor drive using flux linkage increment based on the line-to-line BEMF for electric vehicles

Abstract

BLDC motors are generally used in electric vehicles because of its advantages that have a simple structure, high torque, high efficiency, low maintenance, and reliable operation. Commonly, BLDC motors use position sensors to determine the commutation instant. Unfortunately, the problems that often occur in the use of position sensor are temperature sensitive of the sensor, expensive sensor prices, difficulties and frequent errors during installation with the controller. Therefore, the use of the sensorless method is an alternative solution for determining instant commutation on a BLDC motor. This paper used flux linkage increment for the sensorless method depend on the line-to-line BEMF. The advantages of flux linkage increment method when compared to the zero crossing point (ZCP) method are the determination of commutation instant precisely at the commutation point and does not require 30° shift from ZCP to get commutation instant and should better dynamic performance. In order to determine ZCP, the line-to-line BEMF was used in this paper because it is simple to be used, it has low cost, it can eliminate the neutral line, and it does not require virtual neutral. This method is simulated in low-speed and high-speed motor operation so it will be appropriate when applied to electric vehicles that require dynamic speed.