IJREE- Volume 3 Issue 2 Paper 4


Author’s Name : J.Muthupandi | D.Citharthan | M.Varatharaj

Volume 03 Issue 02  Year 2016  ISSN No:  2349-2503  Page no: 17-21



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 in formation. 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. Index Term Back electromotive force (EMF), brush less DC motor, disturbance observer, sensor less.


bldc motor,back emf estimation,sensorless,pi controller


  1. J. C. Gamazo-Real, E. Vázquez-Sánchez, and J. Gómez-Gil, “Position and speed control of brushless DC motors using sensor less techniques and application trends,” Sensors, vol. 10, pp. 6901-6947, 2010.
  2. P. Damodharan and K. Vasudevan, “Sensor less brushless DC motor drive based on the zero-crossing detection of back electromotive force (EMF) from the line voltage difference,” IEEE Trans. Energy Conver., vol. 25, pp. 661-668, 2010.
  3. K. Taeyeon, K. Chungil, and L. Joon, “A new sensor less drive scheme for a BLDC motor based on the terminal voltage difference,” in Proc. IEEE. Ind. Electron. Society Conf. , 2011, pp. 1710-1715.
  4. J. C. Moreira, “Indirect sensing for rotor flux position of permanent magnet AC motors operating over a wide speed range,” IEEE Trans. Ind. Appl., vol. 32, pp. 1394-1401, 1996.
  5. S. Ogasawara and H. Akagi, “An approach to position sensor less drive for brushless DC motors,” IEEE Trans. Ind. Appl., vol. 27, pp. 928 1933,1991.
  6. Z. M. A. Peixo, F. M. F. Sa, P. F. Seixas, B. R. Menezes, P. C. Cortizo,and W. S. Lacerda, “Application of sliding mode observer for inducede.m.f., position and speed estimation of permanent magnet motors,” In Proc. Int. Conf. Power Electron. Drive Syst., pp. 599-604, vol. 2, 1995.
  7. R. Dhaouadi, N. Mohan, and L. Norum, “Design and implementation ofan extended Kalman filter for the state estimation of a permanent agnet synchronous motor,” IEEE Trans. Power Electron., vol. 6, pp.491-497, 1991.
  8. K. Ohishi, M. Nakao, K. Ohnishi, and K. Miyachi, “Microprocessor-controlled DC motor for load-in sensitive position servo system,” IEEE Trans. Ind. Electron., vol. 34, pp. 44-49, Feb. 1987.
  9. T. Umeno and Y. Hori, “Robust speed control of DC servomotors using modern two degrees-of-freedom controller design,” IEEE Trans. Ind.Electron. , vol. 38, pp. 363-368, 1991.