Split Phase Induction Motor Operation from PWM Voltage Source Inverter

Gopakumar, K and Ranganathan, VT and Bhat, SR (1991) Split Phase Induction Motor Operation from PWM Voltage Source Inverter. In: Conference Record of the 1991 IEEE Industry Applications Society Annual Meeting, 28th September-4th October, Dearborn,Michigan, Vol.1, 437-442.

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Abstract

Split-phase AC motors, with 30 deg. separation between the two groups of stator windings are used in conjunction with current source inverters, in order to eliminate sixth harmonic torque pulsations. The present paper examines the operation of split- phase induction motors from pulse width modulated (PWM) voltage source inverters. Splitting the phase windings leads to reduced voltage ratings for the inverter switches. The inverters are operated with space phasor based PWM. I t is well known that with this technique, a three phase inverter can give a maximum peak fundamental of 0.577 $V_D_C$ for the motor phase voltage (with a circular trajectory for the voltage space phasor), as against 0.5 $V_D_C$ with sine triangle modulation. In the case of split- phase machines operated from two inverters, it can be shown that the equivalent 3 phase maximum peak fundamental can be 0.622 $V_D_C$ with the DC bus voltage being half the value $V_D_C$ for the conventional 3 phase configuration. If the DC bus voltage is given as light boost (in order to keep the resultant voltage space phasor magnitude, the same for the split- phase configuration as compared to the 3 phase configuration), and made (0.5 $V_D_C$ )/cos15, the maximum peak fundamental motor voltage obtainable is 0.643$V_D_C$, which is more than what is obtainable by resorting to six-step operation in the three phase motor. Further, as compared to seven positions for the space phasor of voltage in three phase machines, forty eight different space phasor locations are possible in the split-phase machine. The boundary of the space phasors is now a 12 sided polygon. By switching between locations within the polygon, it is possible to generate reduced space phasor amplitudes with lower harmonics than in the three phase

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:	29 May 2006
Last Modified:	19 Sep 2010 04:27
URI:	http://eprints.iisc.ac.in/id/eprint/7020

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