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an investigation of dual stator winding induction machines

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torque partition factor K has been introduced to distribute the electromagnetic torque to<br />

the two <strong>winding</strong> sets. By ch<strong>an</strong>ging the value <strong>of</strong> K, one <strong>winding</strong> set c<strong>an</strong> move smoothly<br />

from motoring condition into generating condition. The effectiveness <strong>of</strong> the torque<br />

partition factor has been demonstrated by the simulation results. Secondly, a speed<br />

sensorless control scheme based on full-order flux observer using MRAS technique has<br />

been <strong>an</strong>alyzed. A novel error function has been proposed to ensure the stability within<br />

ultra-low speed r<strong>an</strong>ge. The Butterworth method is used to design the observer gains. The<br />

tr<strong>an</strong>sfer function <strong>of</strong> the estimated <strong>an</strong>d actual speeds is derived based on the error <strong>an</strong>alysis,<br />

which is used to determine the parameters <strong>of</strong> speed estimator. The D-decomposition<br />

method is adopted as the design methodology for both speed estimator <strong>an</strong>d speed<br />

controller. The whole system is simulated in both motoring <strong>an</strong>d regenerating modes. The<br />

controllers are working properly <strong>an</strong>d the rotor speed is regulated very well, which<br />

validate the proposed full-order flux observer <strong>an</strong>d speed estimation. Experimental results<br />

validate these simulation results.<br />

12.2 Future Work<br />

There are still several possible areas for the future research on the <strong>dual</strong> <strong>stator</strong> <strong>winding</strong><br />

<strong>induction</strong> machine. The proposed future work is discussed in this section.<br />

Although a coupled circuit model <strong>of</strong> the <strong>dual</strong> <strong>stator</strong> <strong>winding</strong> <strong>induction</strong> machine has<br />

been developed <strong>an</strong>d validated by the simulation <strong>an</strong>d experimental results, the saturation<br />

effect is not included into the model. Some steps for better underst<strong>an</strong>ding <strong>an</strong>d modeling<br />

<strong>of</strong> saturation effect have been made in this dissertation, however because <strong>of</strong> the<br />

complexity <strong>of</strong> flux linkages due to <strong>winding</strong>s <strong>of</strong> dissimilar pole numbers <strong>an</strong>d fed with<br />

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