Position sensorless brushless DC motor/generator drives: review and future trends

Recent advances in the development of fast digital signal processors (DSPs) have paved the way for position sensorless drives of alternating current motors. More sophisticated sensorless drive algorithms in DSPs substitute for the mechanical position sensors and other related hardware. The authors cover a wide range of topics related to the position sensorless control of brushless direct current motor/generator drives including their fundamentals, limitations, present advances and future trends. Conventional techniques are reviewed and recent developments in this area are introduced with their inherent advantages and drawbacks. Anticipated research efforts and trends are also discussed.