Sensorless Direct Torque Control for Saliency Permanent Magnet Brushless DC Motors

Sensorless technology cannot only reduce the cost of motor drive system, but also improve system reliability. In the sensorless direct torque control (DTC) drive system of permanent magnet brushless dc motor (BLDCM), the estimations of instantaneous electromagnetic torque and stator flux linkage are two key issues. Additionally, some BLDCMs with salient-pole phenomenon make the estimations of torque and flux linkage even harder. A sensorless salient-pole BLDCM-DTC drive system is proposed in this paper. A stator current estimator with back electromotive-force (EMF) self-adaptation is first constructed according to stator current state equations and the back EMF is obtained by adaptive law. Then, a phase-locked loop is used to output smooth estimated value of rotor position angle based on the identified back EMF. At last, according to the estimated rotor position angle, the torque and stator flux linkage are calculated to realize saliency BLDCM-DTC running smoothly. Experimental results show that the estimated torque and stator flux linkage are very close to their actual values. The novel sensorless DTC drive system has nice dynamic and static performances, and the lowest steady-state speed can be decreased to 33 r/min.

[1]  Niraj Kishore,et al.  Torque ripples control and speed regulation of Permanent magnet Brushless dc Motor Drive using Artificial Neural Network , 2014, 2014 Recent Advances in Engineering and Computational Sciences (RAECS).

[2]  Tomonobu Senjyu,et al.  New sensorless control for brushless DC motors using disturbance observers and adaptive velocity estimations , 1998, IEEE Trans. Ind. Electron..

[3]  Z.Q. Zhu,et al.  Direct torque control of brushless DC drives with reduced torque ripple , 2004, Conference Record of the 2004 IEEE Industry Applications Conference, 2004. 39th IAS Annual Meeting..

[4]  Jin Gao,et al.  Direct Self-Control for BLDC Motor Drives Based on Three-Dimensional Coordinate System , 2010, IEEE Transactions on Industrial Electronics.

[5]  C. De Angelo,et al.  A rotor position and speed observer for permanent magnet motors with nonsinusoidal EMF waveform , 2002, IEEE 2002 28th Annual Conference of the Industrial Electronics Society. IECON 02.

[6]  S.I. Mousavi,et al.  Position sensorless direct torque control of BLDC motor , 2008, 2008 IEEE International Conference on Industrial Technology.

[8]  J.S. Lawler,et al.  Extending the constant power speed range of the brushless DC motor through dual-mode inverter control , 2004, IEEE Transactions on Power Electronics.

[9]  C.-S. Berendsen,et al.  Commutation strategies for brushless DC motors: influence on instant torque , 1990 .

[10]  Yong Liu,et al.  Commutation-Torque-Ripple Minimization in Direct-Torque-Controlled PM Brushless DC Drives , 2006, IEEE Transactions on Industry Applications.

[11]  Zhang Wenjuan,et al.  Research of interior permanent magnet brushless DC motor for electric vehicles , 2013, 2013 International Conference on Electrical Machines and Systems (ICEMS).

[12]  H.A. Toliyat,et al.  Direct Torque Control of Brushless DC Motor with Non-sinusoidal Back-EMF , 2007, 2007 IEEE International Electric Machines & Drives Conference.

[13]  M. Bahrami Kouhshahi,et al.  Direct torque control of brushless DC motor drives with reduced starting current using fuzzy logic controller , 2011, 2011 International Conference on Uncertainty Reasoning and Knowledge Engineering.

[14]  Seung-Ki Sul,et al.  Direct torque control of brushless DC motor with nonideal trapezoidal back EMF , 1995 .

[15]  P. Damodharan,et al.  Sensorless Brushless DC Motor Drive Based on the Zero-Crossing Detection of Back Electromotive Force (EMF) From the Line Voltage Difference , 2010, IEEE Transactions on Energy Conversion.

[16]  Long Wu,et al.  Direct Torque Control of Brushless DC Motor , 2012 .

[17]  Jianfei Yang,et al.  Direct torque control of Brushless DC motor without flux linkage observation , 2009, 2009 IEEE 6th International Power Electronics and Motion Control Conference.

[18]  Ying-Yu Tzou,et al.  A New Sensorless Starting Method for Brushless DC Motors without Reversing Rotation , 2007, 2007 IEEE Power Electronics Specialists Conference.

[19]  H.A. Toliyat,et al.  Direct torque control of four-switch brushless DC Motor with non-sinusoidal back-EMF , 2008, 2008 IEEE Power Electronics Specialists Conference.