SENSORLESS FLUX REGION MODIFICATION OF DTC CONTROLLED IM FOR TORQUE RIPPLE REDUCTION

Abstract

A Direct Torque Control (DTC) drive allows direct and independent control of flux linkage and electromagnetic torque by the selection of optimum inverter switching tables. There is no need for any complex transformation of current or voltage. However, each vector selected from the switching table cannot produce the required accurate stator voltage vector to provide the desired torque and flux. This results in the production of ripples in the torque as well as flux waveforms. In this study, we propose a method to reduce torque and flux fluctuations. In this method, the flux region of conventional DTC model are modificated and is compared to conventional DTC method. Speed is estimated from MRAS. The conventional MRAS-based sensorless DTC and the flux region modification method are simulated and the comparison of their practice performances is presented.

Keywords

• Induction motor, Direct torque control, Flux Region modification method, MRAS, Torque and Flux Linkage ripple

References

1. X.Li, R. Duke and S. Round., “Development of a three-phase three-level inverter for an electric vehicle”, Australasian Universities PowerEngineering Conf., 1999, Darwin, Australia, pp. 247-251.
2. Sarıoglu M. K., “Fundamentals of Electric Machines I”, ITU, Faculty of Electric- Elec- tronic, Ofset Press Room,3.Press, 1984.
3. Sarıoglu M.K., “Gokasan M., Bogosyan S.,Asynchronous Machines and it’s Con- trol”, Birsen Publishing, ISBN 975-511-343- 6, 2003.
4. Vasudevan M., Arumugam R., “New Direct Torque Control Scheme of Induction Motor for Electric Vehicles”.
5. Parekh R., “AC Induction Motor Fun- damentals”, Microchip Technology Inc., AN887,U.S.A., 2003.
6. Luukko, J., “Direct Torque Control of Per- manent Magnet Synchronous Machines -Analysis and Implementation”, Diss. Lap- peenranta University of Technology, Lap- peenranta, Stockholm, 2000.
7. Okumuş, H.,İ., “Improved Direct Torque Control of Induction Machine Drives”, PhD Thesis, University of Bristol, July, UK, 2001.
8. Mei, C.G., Panda, S.K., Xu, J.X. ve Lim, K.W., “Direct Torque Control of Induction Motor-Variable Switching Sectors”, Proc. of the 3rd Power Electronics and Drive Sys- tems, Proceedings of the IEEE International Conference, 1999, 1:80-85.

9. Schauder, C., “Adaptive Speed identification for vector control of induction motors with- out rotational transducers”, IEEE Tran.Ind. Applic., 5(IA-22): 965-970, 1999.
10. Cirrincione, M. and M. Pucci, “Sensorless direct torque control of an induction motor by a TLS-based MRAS observer with adap- tive integration”, Automatica, 11(41): 1843- 1854, 2005.
11. Kojabali,H.M., L. Chang and R. Doraismi, “A MRAS based adaptive pseudo-reduced order flux observer for sensorless induction motor drivers”, Elec. Power Components Systems, 4(20):930-937, 2005.
12. Kraiem,H.,Ben Hamed,M., Sbita, L. ve Naceuraldulkrim, M., “DTC Sensorless Induction Motor Drives Based on MRAS Simultaneous Estimation of Rotor Speed Stator Resistance” ,International Journal of Electrical and Power Engineering, 2(5):306- 313,2008.
13. SIMULINK Dynamic System Simulation for MATLAB Modeling, Simulation, Im- plementation, The MathWorks, Inc. Natick, Massachusetts,USA,2010.
14. Schauder, C. 1992. Adaptive Speed identifi- cation for vector control of induction motors without rotational transducers. IEEE. Tran. Ind.Applic.,5(IA-22): 965-970.
15. User Y., Gulez K., Ozen S., “Sensorless Twelve Sector Implementation of DTC Con- trolled IM for Torque Ripple Reduction”, 6th International Advaced Technoloqies Sympo- sium, pp. 317-321, May 2011.
16. Y. S. Lai, J. H. Chen, “A new approach to di- rect torque control of induction motor drives for constant inverter switching frequency and torque ripple reduction, IEEE Trans.En- ergy Conversion, vol. 16, pp. 220-227, Sept. 2001.
17. T. G. Habetler, F. Profumo, M. Pastorelli and L. M. Tolbert, “Direct torque control of in- duction machines using space vector modu- lation,” IEEE Trans. Industrial Applications, vol. 28, pp.1045-1053, Sept/Oct 1992.