Title: Low distortion three-phase sine PWM using a general purpose micro-controller

Authors: Suvarun Dalapati; Snehasish Pal

Addresses: Stesalit Limited, Electronic Systems Division, Stesalit Towers, 1st Floor, Block EP & GP, Salt Lake, Sector-V, Kolkata-700091, West Bengal, India. ' Department of Electrical Engineering, JIS College of Engineering, Kalyani, Nadia, Pin-741235, West Bengal, India

Abstract: Three-phase balanced sine-PWM pulses are required for the purpose of generation of sinusoidal output voltage and/or currents from inverters, used for UPS/motor-control applications. Such pulse-generation is possible using micro-controllers/DSPs with PWM output pins. This paper discusses a simple algorithm to generate low distortion balanced three-phase sine-PWM pulses from a general purpose micro-controller, without using PWM pins. It is shown via simulation and experimentation that such an algorithm is capable of achieving current-distortions well below 5%. An inverter, controlled by such an algorithm, is also tested for three-phase AC induction motor control application in V/f mode, using a feed-forward control-methodology. A performance-comparison is made between a general-purpose micro-controller (using the above strategy) and a micro-controller (used for motor-control applications) for the above application-area.

Keywords: pulse width modulation; microcontrollers; THD; AC induction motors; induction motor control; three-phase inverters; constant torque zone; constant power zone; look-up tables; AT89C52; PIC18F4431; current distortion; feedforward control; total harmonic distortion.

DOI: 10.1504/IJPELEC.2012.049044

International Journal of Power Electronics, 2012 Vol.4 No.4, pp.378 - 408

Available online: 04 Sep 2012 *

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