Variable structure direct torque control of encoderless synchronous reluctance motor drives with maximized efficiency

In this paper, a flexible DTC based on variable structure approach and space vector modulation is presented for encoderless Synchronous Reluctance Motor (SynRM) Drives. According to this method, a sliding mode-plus-PI controller is designed for torque and flux control in stator flux reference frame, respectively. The proposed controller is able to reduce the torque, flux, current and speed pulsations during steady-state behavior while the fast response and robustness merits of the classic DTC are preserved. In addition, an on-line adaptive loss minimization controller (ALMC) for SynRM drives is introduced. The ALMC provides a novel pattern of change in stator flux magnitude to achieve a minimum motor input power at any operating condition. The operating of the ALMC results in a smooth and fast loss minimization. Very low speed estimation (5 r/min) is satisfied by the elimination of the voltage sensors' dc offset. The simulation and experimental results obtained verify that the encoderless efficiency-optimized VS-DTC proposed for SynRM drives presents a good performance with minimized number of dependent parameters.

[1]  Toshihiko Noguchi,et al.  A New Quick-Response and High-Efficiency Control Strategy of an Induction Motor , 1986, IEEE Transactions on Industry Applications.

[2]  Mario Pacas,et al.  A predictive torque control for the synchronous reluctance machine taking into account the magnetic cross saturation , 2005, 31st Annual Conference of IEEE Industrial Electronics Society, 2005. IECON 2005..

[3]  H. van der Broeck,et al.  Analysis and Realization of a Pulse Width Modulator Based on Voltage Space Vectors , 1986, 1986 Annual Meeting Industry Applications Society.

[4]  Bimal K. Bose,et al.  Fuzzy logic based on-line efficiency optimization control of an indirect vector-controlled induction motor drive , 1995, IEEE Trans. Ind. Electron..

[5]  Tian-Hua Liu,et al.  Adaptive controller design for a synchronous reluctance motor drive system with direct torque control , 2007 .

[6]  Thomas A. Lipo,et al.  A new control strategy for optimum efficiency operation of a synchronous reluctance motor , 1996 .

[7]  J. Holtz,et al.  Drift and parameter compensated flux estimator for persistent zero stator frequency operation of sensorless controlled induction motors , 2002, Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344).

[8]  John Y. Hung,et al.  Variable structure control: a survey , 1993, IEEE Trans. Ind. Electron..

[9]  A. Tani,et al.  FOC and DTC: two viable schemes for induction motors torque control , 2002 .

[10]  F. Blaabjerg,et al.  Very-low-speed variable-structure control of sensorless induction machine drives without signal injection , 2005, IEEE Transactions on Industry Applications.

[11]  Mario Pacas,et al.  A predictive torque control for the synchronous reluctance machine taking into account the magnetic cross saturation , 2005 .

[12]  Seung-Ki Sul,et al.  Efficiency-optimized direct torque control of synchronous reluctance motor using feedback linearization , 1999, IEEE Trans. Ind. Electron..

[13]  Guillaume J.J. Ducard,et al.  Nonlinear Control Design , 2009 .

[14]  Thomas A. Lipo,et al.  Synchronous reluctance machines―a viable alternative for AC drives? , 1991 .

[15]  V. I. John,et al.  An on-line loss minimization controller for interior permanent magnet motor drives , 1997 .

[16]  Paolo Guglielmi,et al.  Impact of cross-saturation in sensorless control of transverse-laminated synchronous reluctance motors , 2006, IEEE Transactions on Industrial Electronics.

[17]  M.F. Rahman,et al.  Direct Torque and Flux Regulation of an IPM Synchronous Motor Drive Using Variable Structure Control Approach , 2004, IEEE Transactions on Power Electronics.

[18]  Mario Pacas,et al.  Encoderless Predictive Direct Torque Control for Synchronous Reluctance Machines at Very Low and Zero Speed , 2008, IEEE Transactions on Industrial Electronics.

[19]  Seth R. Sanders,et al.  Stator-flux-oriented vector control of synchronous reluctance Machines with maximized efficiency , 2004, IEEE Transactions on Industrial Electronics.