An Efficient PWM Technique for Split Phase Induction Motor Operation Using Dual Voltage Source Inverters

Gopakumar, K and Ranganathan, VT and Bhat, SR (1993) An Efficient PWM Technique for Split Phase Induction Motor Operation Using Dual Voltage Source Inverters. In: Conference Record of the 1993 IEEE Industry Applications Society Annual Meeting, 2-8 October, Toronto,Ontario,Canada, vol.1, 582 -587.

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Abstract

Split phase induction motor operation from dual PWM voltage source inverters offers the advantage of reduced voltage rating for the inverter devices. In addition, a total of 49 different locations are possible for the resultant stator voltage space phasor. The outermost locations form a twelve sided polygon. By space phasor PWM generation based on the vertices of the twelve sided polygon, a higher range of fundamental motor voltage is possible in the modulation range, up to 0.643 $V_{DC}$, where $V_{DC}$ is the DC link voltage for an equivalent 3 phase inverter, as compared to 0.577 $V_{DC}$ for the three phase motor. This is brought about by the presence of 5th and 7th harmonics in the average poler voltage waveform. These harmonics get eliminated in the air gap mmf because of the winding disposition. However, they cause stator Currents to flow and these currents are limited Only by the stator leakage impedance. At low speeds, these currents can be very high. In this paper a PWM strategy is proposed for a split phase induction motor drive, wherein at low speeds each of the inverters is operated with conventional three and 7th harmonics in the motor voltage. At the higher end of the speed range a voltage space phasor modulation based on the twelve sided polygonal vertices is used, so that the benefit of a higher speed in the modulation range is retained. A technique for achieving the transition to that range without current transients is proposed. The scheme is verified through computer simulation, using a space phasor based model of the split phase motor. Details of a practical control circuit for voltage space phasor based PWM pulse generation are presented and the results from an experimental drive are highlighted.

Item Type:	Conference Paper
Publisher:	IEEE
Additional Information:	Copyright 1990 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Department/Centre:	Division of Electrical Sciences > Electronic Systems Engineering (Formerly Centre for Electronic Design & Technology) Division of Electrical Sciences > Electrical Engineering
Date Deposited:	25 May 2006
Last Modified:	19 Sep 2010 04:27
URI:	http://eprints.iisc.ac.in/id/eprint/6893

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