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an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

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V<br />

dc<br />

= −<br />

2<br />

3R<br />

( R + γ ⋅ R )<br />

L1<br />

R<br />

L3<br />

L1<br />

Re<br />

L3<br />

⎡<br />

⎢<br />

⎢M<br />

⎢<br />

⎢<br />

⎢⎣<br />

*<br />

qds1<br />

λ<br />

qdm1<br />

L<br />

m1<br />

A ⎤<br />

r1<br />

Llr1<br />

+ Lm1<br />

⎥<br />

Br1<br />

− jωs1<br />

⎥<br />

⎛<br />

A ⎞⎥<br />

r1<br />

⎜ L +<br />

⎟<br />

lr1<br />

Lls1<br />

⎥<br />

⎝ Br1<br />

− jωs1<br />

⎠⎥⎦<br />

A similar equation c<strong>an</strong> be obtained from the XYZ <strong>winding</strong> set as shown in (9.28).<br />

V<br />

dc<br />

= −<br />

2<br />

3R<br />

( R + ( 1−γ<br />

) R )<br />

L2<br />

L3<br />

R<br />

L2<br />

L3<br />

⎡<br />

⎢<br />

Re⎢M<br />

⎢<br />

⎢<br />

⎢⎣<br />

*<br />

qds2<br />

λ<br />

qdm2<br />

A ⎤<br />

r2<br />

Llr2<br />

+ Lm2<br />

⎥<br />

Br<br />

2 − jωs2<br />

⎥<br />

⎛<br />

A ⎞⎥<br />

r2<br />

L ⎜ +<br />

⎟<br />

m2<br />

Llr2<br />

Lls2<br />

⎥<br />

⎝ Br<br />

2 − jωs2<br />

⎠⎥⎦<br />

324<br />

(9.27)<br />

(9.28)<br />

The saturation effect <strong>of</strong> the <strong>induction</strong> generator is included in the <strong>an</strong>alysis by varying<br />

the magnetizing induct<strong>an</strong>ce with the magnetizing flux linkage. The main flux saturation<br />

curve fit <strong>of</strong> the experimental results <strong>of</strong> 2-pole ABC <strong>winding</strong> set is shown in Figure 9.4(a).<br />

Fixing the coefficient γ , the slip <strong>an</strong>d the load resist<strong>an</strong>ces to be const<strong>an</strong>t <strong>an</strong>d varying the<br />

magnetizing flux linkage, the variation <strong>of</strong> the magnitude <strong>of</strong> the modulation index with the<br />

magnetizing flux c<strong>an</strong> be found from (9.23-9.24) is displayed in Figure 9.4(a). Three<br />

different load resist<strong>an</strong>ce values have been given to R L1<br />

to demonstrate the influence <strong>of</strong><br />

the load resist<strong>an</strong>ce on dc voltage generation. The ellipses relating the dc voltage <strong>an</strong>d q-<br />

axis modulation index <strong>of</strong> the ABC <strong>winding</strong> set at different load resist<strong>an</strong>ce values are<br />

shown in Figure 9.4 (b). Similar curves for the rectifier connected to the XYZ <strong>winding</strong>s<br />

c<strong>an</strong> be calculated using (9.28). Under const<strong>an</strong>t γ , const<strong>an</strong>t slip, const<strong>an</strong>t magnetizing<br />

flux linkage <strong>an</strong>d a const<strong>an</strong>t load resist<strong>an</strong>ce condition, by varying the q-axis modulation<br />

index, the variation <strong>of</strong> dc voltage <strong>of</strong> the rectifier connected to the ABC <strong>winding</strong> set is in<br />

the form <strong>of</strong> ellipse shown in Figure 9.5(a). Note that equations (9.26-9.27) independently<br />

define the same output dc voltage Vdc. It follows that the feasible values are defined by<br />

the overlapping regions <strong>of</strong> the two curves. As c<strong>an</strong> be seen from the Figure 9.4(b) <strong>an</strong>d

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