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an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

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voltages <strong>of</strong> different frequencies, a good saturation modeling method accounting for<br />

harmonic flux linkage components needs to be developed. The field <strong>an</strong>alysis method may<br />

be one <strong>of</strong> the approaches that c<strong>an</strong> be applied to study the saturation effect <strong>of</strong> the <strong>induction</strong><br />

machine. In previous work, a modified air gap function has been proposed to model the<br />

saturation effect <strong>of</strong> single <strong>stator</strong> <strong>winding</strong> <strong>induction</strong> machine. If the same modified air gap<br />

function is included in the field <strong>an</strong>alysis, a new methodology for saturation <strong>an</strong>alysis will<br />

be obtained. Instead <strong>of</strong> ch<strong>an</strong>ging the air gap function, the air gap permeability c<strong>an</strong> be<br />

modified to achieve a similar result for saturation modeling. The adv<strong>an</strong>tage <strong>of</strong> varying air<br />

gap permeability is that the air gap function c<strong>an</strong> be modified to include the eccentricity in<br />

the modeling <strong>an</strong>d <strong>an</strong>alysis. So if the air gap permeability function reflects the saturation<br />

effect <strong>an</strong>d the air gap length function reflects the eccentricity effect, these two conditions<br />

c<strong>an</strong> be included in the <strong>an</strong>alysis at the same time to find the harmonics <strong>of</strong> a saturated<br />

<strong>induction</strong> machine with rotor eccentricity, which may be useful for <strong>induction</strong> machine<br />

fault diagnosis. The results from the saturation modeling will also directly affect the<br />

machine design methodology <strong>of</strong> <strong>dual</strong> <strong>winding</strong> <strong>induction</strong> machine.<br />

The stability <strong>an</strong>alysis <strong>of</strong> <strong>dual</strong> <strong>stator</strong> <strong>winding</strong> <strong>induction</strong> machine is <strong>an</strong>other area for<br />

future work. When a converter fed <strong>dual</strong> <strong>stator</strong> <strong>winding</strong> <strong>induction</strong> machine works as a<br />

motor, system instability has been experimentally observed. The <strong>an</strong>alysis results on the<br />

instability r<strong>an</strong>ge in motoring condition under either const<strong>an</strong>t V/f control or vector control<br />

will be helpful to the real industry application. Instability when the <strong>dual</strong> <strong>stator</strong> <strong>winding</strong><br />

<strong>induction</strong> generator is fed with series connected boost PWM rectifiers has been observed<br />

during the experiments. The stability <strong>an</strong>alysis for that system configuration has not yet<br />

been studied.<br />

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