Analysis of BLDC Motors and Modeling of Sensorless Drive

Abstract

Up to now, BLDC motors are more attractive for many industrial applications due to high efficiency and high power density. However, for the coming of robotic generation, the utilization of BLDC motors should be more efficient and have better performance. In order to achieve this purpose, the characteristics of BLDC motors are analyzed by analytic and FEM based methods. Besides, an integrated sensorless drive method based on sliding mode observer is proposed. The results of FEM analysis are employed to establish an explicit mathematic model so that the unexpected error of the actual control system can be reduced. The proposed sensorless drive method is able to drive a BLDC motor from standstill to desired speed in wide speed range. The fault of start-up, which exits in conventional sensorless drive method, has been overcome. The integrated procedure for establishing the sensorless drive system of BLDC motors is presented in this thesis.