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an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

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frequency <strong>of</strong> the XYZ <strong>winding</strong> set is always positive under this condition. From Figure<br />

7.22, it is obvious that under const<strong>an</strong>t output mech<strong>an</strong>ical power condition a minimum<br />

copper loss operating point c<strong>an</strong> be found. It is found that the optimal slip frequencies <strong>of</strong><br />

the ABC <strong>winding</strong> set under different rotor speed conditions are very close to each other.<br />

The electromagnetic torque contributions <strong>of</strong> the ABC <strong>an</strong>d XYZ <strong>winding</strong> sets are shown<br />

in Figure 7.23 <strong>an</strong>d Figure 7.24 respectively. The comparison <strong>of</strong> slip frequencies under<br />

different total electromagnetic torque values for one const<strong>an</strong>t rotor speed is given in<br />

Figure 7.25. The corresponding copper losses <strong>of</strong> the machine are compared as shown in<br />

Figure 7.26.<br />

Since better controllability in the very low speed r<strong>an</strong>ge is one <strong>of</strong> the adv<strong>an</strong>tages <strong>of</strong><br />

this type <strong>of</strong> machine, the rotor speed <strong>of</strong> <strong>dual</strong> <strong>stator</strong> <strong>winding</strong> <strong>induction</strong> machine is forced<br />

in this speed r<strong>an</strong>ge to <strong>an</strong>alyze the machine perform<strong>an</strong>ce under this operating condition.<br />

The simulation results are shown in Figure 7.27-7.30.<br />

Figure 7.27. ω s1<br />

vs s2<br />

ω when the total electromagnetic torque <strong>an</strong>d the rotor mech<strong>an</strong>ical speed<br />

are const<strong>an</strong>t.<br />

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