MODELLING AND ANALYSIS OF A TWO PHASE INDUCTION MACHINE WITH NON-ORTHOGONAL STATOR WINDINGS

T SREEJITH KAILASEdited By

Sarath S Nairwww.technologyfuturae.com

MODELLING AND ANALYSIS OF A TWO PHASE INDUCTION MACHINE WITH

NON-ORTHOGONAL STATOR WINDINGS

IntroductionStarting torque is produced by designing

the stator windings to be electrically different.

Unsymmetrical 2-phase IM is designed to operate from a single-phase source

Stationary reference frame is used in order to obtain voltage equations with constant coefficients.

Rating of two phase induction machine is usually low.

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2Pole,Unsymmetrical 2-phase induction machine

θr

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VQS,VDS=QS and DS-axis stator voltages

Rm,Xm and Ra,Xsa-QS and DS-axis resistance and leakage inductanceRotor voltages are set to zero(because of squirrel-cage rotors)

Voltage and flux equations

4

VDS=Ra*iDS+(P/ωb*ψDS)……(2)

VQS=Rm*iQS+ (P/ωb*ψQS)……(1)

 0=(Rr*iQR)-1/k* (ωr/ωb)*ψ’DR+(P/ωb)*ψ’QR …….(3)0=(K^2*Rr*iDR)-k*

(ωr/ωb)*ψ’QR+(P/ωb)*ψ’DR .....(4)www.technologyfuturae.com

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Te,Tl =electromagnetic instantaneous torque and load torque

J= inertia constant of motorP= number of poles

Torque Equation

7

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8

Equivalent circuit

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AdvantagesRobustness in its operationLow costHighly reliable

DisadvantageInability to produce a smoothly rotating

internal fluxNeeds two capacitors

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ApplicationsMostly used in single phase applications

such asRefrigeratorsWashing machinesFurnace fansAir conditioners

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ReferencesKrause, P.C., Wasynczuk, O., Sudhoff,

S.D.,Analysis of Electric Machinery, IEEE Press, 1995.

Walls, T.A., Sudhoff, S.D., Analysis of a single-phase induction machine with a shifted auxiliary winding, IEEE, Trans. on Energy Conversion, dec.1996, p.681-686.

http://www.wikepedia.com/two phase induction motor.html

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ConclusionThe mathematical model for a two-phase

unsymmetrical induction machine was developed and its equivalent circuit is drawn

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