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an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

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the XYZ <strong>winding</strong> set. The designed rotor mech<strong>an</strong>ical speeds <strong>of</strong> both <strong>stator</strong> <strong>winding</strong> sets<br />

are the same to improve the efficiency <strong>of</strong> the system.<br />

If the air gap efficiency <strong>an</strong>d the air gap power factor <strong>of</strong> both <strong>winding</strong> sets are assumed<br />

to be equal, the output mech<strong>an</strong>ical power ratio is expressed as:<br />

P<br />

P<br />

ABC<br />

XYZ<br />

α B1K<br />

= =<br />

1−<br />

α B K<br />

2<br />

s1<br />

s2<br />

( rms)<br />

( rms)<br />

78<br />

(2.102)<br />

The value <strong>of</strong> the mech<strong>an</strong>ical power partition factor α determines the mech<strong>an</strong>ical<br />

power generated by each <strong>of</strong> the two <strong>winding</strong> sets <strong>an</strong>d its value varies from 0 to 1. This<br />

mech<strong>an</strong>ical power partition factor is given as part <strong>of</strong> the design requirements, however,<br />

the value <strong>of</strong> α may be ch<strong>an</strong>ged for different design objectives.<br />

If the surface current density ratio is expressed as:<br />

K<br />

s2<br />

( rms)<br />

s1<br />

ε =<br />

(2.103)<br />

given :<br />

K<br />

( rms)<br />

The ratio <strong>of</strong> the air gap flux densities due to the two <strong>winding</strong> sets from (2.102) is<br />

B<br />

B<br />

1<br />

2<br />

α<br />

=<br />

( 1−<br />

α )ε<br />

The values <strong>of</strong> the air gap flux densities 1<br />

B <strong>an</strong>d 2<br />

(2.104)<br />

B are determined by solving (2.99)<br />

<strong>an</strong>d (2.104). The simulation results <strong>of</strong> the air gap flux densities under different values <strong>of</strong><br />

α <strong>an</strong>d B max are given in Figure 2.8. It is found from the simulation results that the air<br />

gap flux density due to the ABC <strong>winding</strong> set increases to output more power when α<br />

increases from 0 to 1. The air gap flux density due to the ABC <strong>winding</strong> set under the<br />

same mech<strong>an</strong>ical power partition factor condition increases as the surface current density

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