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an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

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diminish the contribution <strong>of</strong> the 6-pole <strong>winding</strong> set to the effective air-gap flux density.<br />

This study indicates that <strong>an</strong> underst<strong>an</strong>ding <strong>of</strong> the nature <strong>an</strong>d magnitudes <strong>of</strong> space<br />

harmonics in addition to the fundamental components rather th<strong>an</strong> the peak values alone<br />

or generalized average values <strong>of</strong> the two domin<strong>an</strong>t flux densities is import<strong>an</strong>t in the<br />

selection <strong>of</strong> the specific magnetic loading <strong>of</strong> the machine [6.5].<br />

The dynamic model <strong>of</strong> a <strong>dual</strong> <strong>stator</strong> <strong>winding</strong> <strong>induction</strong> machine including the air gap<br />

main flux linkage saturation effect is also presented in this chapter. It is argued that in the<br />

light <strong>of</strong> experimental <strong>an</strong>d simulation results, the inter-<strong>winding</strong> induced flux linkages c<strong>an</strong><br />

be ignored with little loss <strong>of</strong> prediction accuracy for the fundamental component state<br />

variables. A common reference frame speed is determined <strong>an</strong>d chosen for computer<br />

simulations to ensure that the inst<strong>an</strong>t<strong>an</strong>eous total air gap flux linkage due to the<br />

contributions <strong>of</strong> the two <strong>winding</strong>s <strong>of</strong> dissimilar pole numbers is aligned with the d-axis <strong>of</strong><br />

the reference frame. Thus the main air-gap flux linkage saturation is included in the<br />

machine model by varying the saturation dependent d-axis magnetizing induct<strong>an</strong>ces <strong>an</strong>d<br />

setting the const<strong>an</strong>t q-axis magnetizing induct<strong>an</strong>ces to be equal to the unsaturated values.<br />

The resulting model is used to illustrate the differences in tr<strong>an</strong>sient <strong>an</strong>d dynamic<br />

perform<strong>an</strong>ce measures with <strong>an</strong>d without the inclusion <strong>of</strong> the saturation <strong>of</strong> the <strong>stator</strong> <strong>an</strong>d<br />

rotor teeth reflected in the air-gap flux density. Experimental results for a 2hp, 2/6<br />

machine validate the proposed simulation model.<br />

The modeling methodology adopted in this chapter for the underst<strong>an</strong>ding <strong>an</strong>d<br />

computer simulation <strong>of</strong> the influence <strong>of</strong> saturation effects on the effective air-gap flux<br />

density arising from the interactions <strong>of</strong> flux linkages due to <strong>winding</strong>s <strong>of</strong> dissimilar pole<br />

numbers <strong>an</strong>d fed with voltages <strong>of</strong> different frequencies should find utility in the <strong>an</strong>alysis<br />

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