—In a permanent magnet (PM) brushless dc motor
(BLDC), the performance of Hall effect sensors are not reliable
in some applications. The back electromotive force (back-EMF)
signal is used instead since the zero-crossing points of
back-EMF can be used to provide the rotor position
information. In this paper, a new back-EMF difference
detection method based on disturbance observer is proposed.
The proposed structure can detect the back-EMF as well as
back-EMF difference signal. The zero-crossing points of the
back-EMF difference can be used directly for commutation,
requiring no phase shift. Simulation and experiment results are
provided to show the feasibility of the proposed method.
—Back electromotive force (EMF), brushless
DC motor, disturbance observer, sensorless.
Samuel Wang and An-Chen Lee are with the National Chiao Tung
University, Hsinchu, Taiwan (e-mail: samuel6113@ hotmail.com.tw,
Chin-Hsuan Lu was with National Chiao Tung University, Hsinchu,
Taiwan. He is with the DELTA, Taoyuan, Taiwan (e-mail:
Cite: Samuel Wang, Chin-Hsuan Lu, and An-Chen Lee, "Disturbance Observer Structure Applied to Sensorless Brushless DC Motors Drive," International Journal of Computer Theory and Engineering vol. 7, no. 2, pp. 92-96, 2015.