Abstract：The direct back electromotive force(EMF) detection method by synchronously sampling the motor back EMF during the pulse width modulation (PWM) off time has been extensively applied in a sensorless brushless DC (BLDC) motor drive. But this direct back EMF sensing scheme is only suitable for the mode whose high side switch is PWM and low side switch is on. On the basis of the research into the traditional model and the working principle of the brushless DC motor, a simplified model of the brushless DC motor is formulated, by which an analysis of the voltage characteristics under different PWM technologies is made. A method of obtaining the back EMF zero-crossing information by comparing the open phase voltage with one half of DC link voltage during PWM on time is proposed and experimented on the prototype. The experimental results show that the proposed control algorithm does satisfactory performance over a wide operation range under various PWM modulation modes.
薛晓明, 杨翀. 一种统一的无刷直流电机直接反电动势法[J]. 电工技术学报, 2010, 25(9): 62-68.
Xue Xiaoming, Yang Chong. A Unified Approach to Direct Back EMF Detection for Brushless DC Motor. Transactions of China Electrotechnical Society, 2010, 25(9): 62-68.
[1] Johnson J P, Ehsani M, Guzelgunler Y. Review of sensorless methods for brushless DC[C]. Proceeding of the IEEE IAS Conference, 1999, 1: 143-150. [2] Iizuka K, Uzuhashi H, Kano M, et al. Microcomputer control for sensorless brushless motor[J]. IEEE Transactions on Industry Applications, 1985, 21(4): 595-601. [3] Jung D H, Ha I J. Low cost sensorless control of brushless DC motors using a frequency-independent phase shifter[J]. IEEE Transactions on Power Electronics, 2000, 15(4): 744-752. [4] Su G J, Mc Keever J W. Low cost sensorless control of brushless DC motors with improved speed range[J]. IEEE Transactions on Power Electronics, 2004, 19(2): 296-302. [5] Yong Ho Yoon, Tae Won Lee, Sang Hun Park, et al. New approach to rotor position detection and precision speed control of the BLDC motor[C]. IEEE Industrial Electronics, IECON 32nd Annual, 2006, 11: 1305-1310. [6] Ogasawara S, Akagi H. An approach to position sensorless drive for brushless DC motors[J]. IEEE Transactions on Industry Applications, 1991, 27(5): 928-933. [7] Shao J, Nolan D, Hopkins T. A novel microcontroller based sensorless brushless DC (BLDC) motor drive for automotive fuel pumps[J]. IEEE Transactions on Industry Applications, 2003, 39(6): 1734-1740. [8] Shao J, Nolan D, Hopkins T. Improved direct back EMF detection for sensorless brushless DC (BLDC) motor drives[C]. Proceeding of IEEE APEC, 2003: 300-305. [9] Yen Shin Lai, Young Kai Lin. A unified approach to back-EMF detection for brushless DC motor drives without current and hall sensors[C]. IEEE Industrial Electronics, IECON 32nd Annual, 2006, 11: 1166- 1171. [10] Microelectronics ST application note AN1130.An introduction to sensorless brushless DC motor drive applications with the ST72141.website www.st.com. [11] 张磊, 瞿文龙, 陆海峰, 等. 一种新颖的无刷直流电机无位置传感器控制系统[J]. 电工技术学报, 2006, 21(10): 26-30. [12] 张磊, 肖伟, 瞿文龙. 直接检测无刷直流电机转子位置信号的方法[J]. 清华大学学报(自然科学版), 2006, 45(4): 453-456.
2010, Vol. 25 
