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an investigation of dual stator winding induction machines

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If a common reference frame speed is properly chosen so that the total air gap flux<br />

linkage is aligned with the d-axis <strong>of</strong> the reference frame at all times, then the total air gap<br />

flux linkage on the q-axis <strong>an</strong>d its derivative will always be zero [6.4]. Hence,<br />

Llr1<br />

Lm1<br />

Lls1Lm1<br />

Llr<br />

2i<br />

Lm2<br />

Lls2<br />

Lm2<br />

λ qm = λqs1<br />

+ λqr1<br />

+ λqs2<br />

+ λqr<br />

2 = 0<br />

(6.15)<br />

D D D D<br />

1<br />

1<br />

2<br />

If the leakage induct<strong>an</strong>ces are all assumed to be const<strong>an</strong>t, the time derivative <strong>of</strong> the<br />

total air gap flux linkage on the q-axis is:<br />

Llr1<br />

Lm1<br />

Lls1Lm1<br />

Llr2i<br />

Lm2<br />

Lls2Lm<br />

2<br />

pλ qm = pλqs1<br />

+ pλqr1<br />

+ pλqs2<br />

+ pλqr2<br />

= 0<br />

(6.16)<br />

D D D<br />

D<br />

1<br />

1<br />

Substituting (6.8-6.9) into (6.16) to eliminate the derivative terms, then<br />

A<br />

r1<br />

V<br />

− A<br />

− B<br />

where,<br />

qs1<br />

s1<br />

ss2<br />

− B<br />

( ω − ω )<br />

λ<br />

qr 2<br />

rr1<br />

λ<br />

r1<br />

+ B<br />

L<br />

L<br />

qs1<br />

λ<br />

dr1<br />

sm2<br />

+ B<br />

λ<br />

lri mi A ri = ,<br />

Di<br />

r<br />

L<br />

qs2<br />

rm1<br />

+ A<br />

si mi<br />

B smi = Asi<br />

, = 1,<br />

2<br />

Di<br />

i .<br />

λ<br />

r 2<br />

− A<br />

qr1<br />

V<br />

qs2<br />

s2<br />

L<br />

− A ωλ<br />

r1<br />

− B<br />

lsi mi A si = ,<br />

Di<br />

rr 2<br />

λ<br />

( ω − ω ) λ = 0<br />

L<br />

r 2<br />

ds1<br />

qs2<br />

2<br />

− B<br />

+ B<br />

dr 2<br />

ss1<br />

λ<br />

rm2<br />

r<br />

246<br />

qr1<br />

λ<br />

qr 2<br />

L<br />

2<br />

+ B<br />

si ri<br />

B rri = Ari<br />

,<br />

Di<br />

2<br />

sm1<br />

− A<br />

λ<br />

r 2<br />

qs1<br />

ωλ<br />

ds2<br />

r<br />

L<br />

si mi<br />

B rmi = Ari<br />

,<br />

Di<br />

The electrical speed <strong>of</strong> common reference frame from (6.17) is given as:<br />

A<br />

r1<br />

V<br />

qs1<br />

− B<br />

rr1<br />

λ<br />

qs1<br />

r1<br />

+ B<br />

ds1<br />

rm1<br />

λ<br />

qr1<br />

s1<br />

− B<br />

dr1<br />

ss1<br />

λ<br />

qr1<br />

r 2<br />

+ B<br />

ds2<br />

sm1<br />

λ + A ω λ<br />

qs1<br />

s2<br />

dr2<br />

s1<br />

r1<br />

dr1<br />

(6.17)<br />

r<br />

L<br />

si si<br />

B ssi = Asi<br />

,<br />

Di<br />

Ar<br />

2Vqs2<br />

− Brr2λ<br />

qs2<br />

+ Brm2λqr2<br />

− Bss2λ<br />

qr2<br />

+ Bsm2λ<br />

qs2<br />

+ As2ω<br />

r 2λdr2<br />

ω = (6.18)<br />

A λ + A λ + A λ + A λ<br />

Then substituting (6.15) into (6.18) to eliminate λ qr 2 , the desired electrical speed <strong>of</strong><br />

the common reference frame is obtained. By aligning the total air gap flux linkage to d-<br />

axis, the q-axis magnetizing induct<strong>an</strong>ces <strong>of</strong> the two sets <strong>of</strong> <strong>winding</strong> are const<strong>an</strong>t at the<br />

unsaturated values. Then the total air gap flux linkage then becomes (6.19):<br />

+

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