Brushless Direct Current Motor Control Using Sensorless Single-signal Feedback

Abstract

This report is a study into the use of a novel Compound back Electromotive Force (CBEMF) method for driving brushless direct current (BLDC) motors. The study was conducted in an attempt to find a simpler drive-method that would allow fast motor rotation with less powerful microcontrollers. The results show this method to be viable, and that further study may be beneficial. CBEMF signal is a composite signal containing feedback information from all 3 motor phases.

By utilizing the CBEMF principle one can design a controller to run very high speed motors in closed-loop control without the need for sensors. The CBEMF principle will also reduce the processing needs in the controller by a significant amount.