A Novel Digital Implementation of AC Voltage Controller for Speed Control of Induction Motor

Authors: Ali M. Eltamaly, A. I. Alolah, R. Hamouda, M. Y. Abdulghany

Abstract:

In this paper a novel, simple and reliable digital firing scheme has been implemented for speed control of three-phase induction motor using ac voltage controller. The system consists of three-phase supply connected to the three-phase induction motor via three triacs and its control circuit. The ac voltage controller has three modes of operation depending on the shape of supply current. The performance of the induction motor differs in each mode where the speed is directly proportional with firing angle in two modes and inversely in the third one. So, the control system has to detect the current mode of operation to choose the correct firing angle of triacs. Three sensors are used to feed the line currents to control system to detect the mode of operation. The control strategy is implemented using a low cost Xilinx Spartan-3E field programmable gate array (FPGA) device. Three PI-controllers are designed on FPGA to control the system in the three-modes. Simulation of the system is carried out using PSIM computer program. The simulation results show stable operation for different loading conditions especially in mode 2/3. The simulation results have been compared with the experimental results from laboratory prototype.

Keywords: FPGA, Induction motor, PSIM, triac, Voltage controller.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1081771

References:

[1] Lipo, T.A., "The analysis of induction motors with voltage control by symmetrically triggered thyristors," IEEE Trans. Power Apparatus and Systems, vol. PAS-90, no. 2, 1971, pp. 515-525.
[2] Hamed, S. and Chalmers, B., " Analysis of variable-voltage thyristor controlled induction motors" IEE Proc., Vol. 137(3), Pt. B, pp. 184-193, May 1990.
[3] Kamaike, H. "Elevator speed control system" U.S. Patent 4052651, Oct. 1977.
[4] Morters et. al. "Control system for regulating the speed of an electric motor" U.S. Patent 4093898, June 1978.
[5] A. I. Alolah, Ali M. Eltamaly, and R. M. Hamouda " Control Limits of Three-Phase ac Voltage Controller under Induction Motor Load" Conf. Proc. of IEEE, International Conference on Electrical Machines, ICEM06, Chania, Crete Island, Greece, Sept. 2006.
[6] Li, W. X., Lui, J. G., LIU, M.ÔÇóS., and ZHAO, J. " Design of intelligent soft-start controller for induction motor " Proc. of the Third International Conference on Machine Learning and Cybernetics, Shanghai, August 2004, pp. 908-912.
[7] H. A. Ashou; R.A. Ibrahim, "Comparison Analysis of ac Voltage Controllers Based on Experimental and Simulated Application Studies" Computer Engineering and Systems, The 2006 International Conference on 2006 Ppp.79 - 84.
[8] H. A. Ashour; R.A. Ibrahim, "Implementation and Analysis of Microcontroller Based Soft Starters for Three Phase Induction Motors" EUROCON, 2007. The International Conference on "Computer as a Tool" Sept. 2007 PP.2193 - 2199.
[9] A. Gastli,; M. M. Ahmed, "ANN-Based Soft Starting of Voltage- Controlled-Fed IM Drive System", IEEE Transaction on Energy Conversion, VOL. 20, #3, 2005, PP.497 - 503
[10] Xu Dianguo; Zhao Kaiqi; Wang Yi; "A new approach to speed detection and power factor angle control on DSP-based soft-starter-fed IM drive system" Industrial Electronics Society, 2003. IECON '03. The 29th Annual Conference of the IEEE vol.1, 2003, PP. 720 - 725.
[11] Rajaji, L.; Kumar, C.; "daptive Neuro Fuzzy based soft starting of voltage-controlled induction motor drive" Southeastcon, 2008. IEEE, April 2008, PP. 448 - 453.
[12] Ali M. Eltamaly "A Modified Harmonics Reduction Technique for a Three-Phase Controlled Converter", IEEE Transactions on Industrial Electronics, vol. 55, # 3, March 2008 PP.1190 - 1197.
[13] Bhuvaneswari, G.; Charles, S.; Nair, M.G.;"Power quality studies on a Soft-start for an induction motor" Transmission and Distribution Conference and Exposition, 2008. T&D. IEEE/PES, April 2008, PP.1-6.
[14] PSIM6.1, available: www.powersimtech.com.
[15] M. G. Solveson, "Soft started induction motor modeling and heating issues for different starting profiles using a flux linkage ABC-frame of reference," M.S. thesis, Marquette Univ., Milwaukee, WI, May 2004.
[16] M. G. Solveson, B. Mirafzal, and N. A. O. Demerdash, "Soft-Started Induction Motor Modeling & Heating Issues for Different Starting Profiles Using a Flux Linkage ABC Frame of Reference", IEEE Trans. Industry Applications, Vol. 42, No. 4, PP. 973-982, July/August 2006.
[17] UG257, MicroBlaze™ Development Kit Spartan-3E 1600E Edition User Guide, www.xilinx.com.
[18] UG129, PicoBlaze™ 8-bit Embedded Microcontroller User Guide, www.xilinx.com.