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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 expression <strong>of</strong> torque distribution factor is expressed as:<br />

K<br />

where, e1<br />

T<br />

T + T<br />

e1<br />

= (10.40)<br />

e1<br />

e2<br />

T <strong>an</strong>d T e2<br />

are the electromagnetic torque from ABC <strong>winding</strong> set <strong>an</strong>d XYZ<br />

<strong>winding</strong> set respectively.<br />

From (10.40), the electromagnetic torque <strong>of</strong> ABC <strong>winding</strong> is given as:<br />

T<br />

e1<br />

= K<br />

e1<br />

= K ⋅<br />

λ i<br />

r1<br />

qs1<br />

( K λ i + K λ i )<br />

e1<br />

r1<br />

qs1<br />

e2<br />

r 2 qs2<br />

352<br />

(10.41)<br />

Replacing the total torque with the output <strong>of</strong> speed controller <strong>an</strong>d the load torque,<br />

(10.41) becomes:<br />

T<br />

e1<br />

= K<br />

= K ⋅<br />

e1λr1iqs1<br />

( J ⋅σ<br />

+ T )<br />

ω<br />

L<br />

(10.42)<br />

The expression <strong>of</strong> the q-axis current comm<strong>an</strong>d for the ABC <strong>winding</strong> set is given as:<br />

K ⋅<br />

( J ⋅σ<br />

ω + T )<br />

*<br />

L<br />

iqs1<br />

= (10.43)<br />

Ke1λr1<br />

Similarly, the expression <strong>of</strong> the q-axis current comm<strong>an</strong>d for the XYZ <strong>winding</strong> set is<br />

determined by:<br />

i<br />

( 1−<br />

K ) ⋅ ( J ⋅σ<br />

ω + T )<br />

*<br />

L<br />

qs2<br />

= (10.44)<br />

Ke<br />

2λr<br />

2<br />

By properly choosing the torque distribution factor K, the comm<strong>an</strong>d q-axis currents<br />

<strong>of</strong> both <strong>stator</strong> <strong>winding</strong> sets c<strong>an</strong> be determined. In the case where the machine is running<br />

at a very low speed <strong>an</strong>d one <strong>of</strong> the <strong>stator</strong> <strong>winding</strong> set needs to generate negative torque, K<br />

c<strong>an</strong> be chosen as a negative value so that the ABC <strong>winding</strong> set is generating or K c<strong>an</strong> be<br />

greater that 1 to force the XYZ <strong>winding</strong> set to generate.

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