Position Sensorless Control Based on Coordinate Transformation for Brushless DC Motor Drives

This paper presents a novel method for sensorless brushless dc (BLDC) motor drives. Based on the characteristics of the back electromotive force (EMF), the rotor position signals would be constructed. It is intended to construct these signals, which make the phase difference between the constructed signals and the back EMFs controllable. Then, the rotor-position error can be compensated by controlling the phase-difference angle in real time. In this paper, the rotor-position-detection error is analyzed. Using the TMS320F2812 chip as a control core, some experiments have been carried out on the prototype, which is the surface-mounted permanent magnet BLDC motor, and the experimental results verify the analysis and demonstrate advantages of the proposed sensorless-control method.