Title: 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

Addresses: Department of EE, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia. ' Department of EE, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia. ' Department of EE, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia. ' Department of EE, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia

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 order for the 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 the FPGA to control the system for the three modes. Simulation of the system is carried out using PSIM computer programme. 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: field programmable gate arrays; FPGA; induction motors; PSIM; triac; AC voltage control; speed control; digital firing; controller design; simulation.

DOI: 10.1504/IJPEC.2010.030862

International Journal of Power and Energy Conversion, 2010 Vol.2 No.1, pp.78 - 94

Received: 27 Feb 2009
Accepted: 14 Sep 2009
Published online: 10 Jan 2010 *

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