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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 is obtained by multiplying the electric field <strong>of</strong> the XYZ <strong>winding</strong> set<br />

with the <strong>winding</strong> distribution <strong>of</strong> the phase A as:<br />

2π<br />

() t = rl C ( θ ) ⋅ E ( θ t)<br />

∫<br />

u A<br />

pq θ<br />

(5.28)<br />

0<br />

2 , d<br />

Substituting the expression <strong>of</strong> phase A <strong>winding</strong> distribution <strong>an</strong>d the electric field <strong>of</strong><br />

the XYZ <strong>winding</strong> set into (5.28) <strong>an</strong>d integrating, the voltage equation is given as:<br />

j(<br />

ω2t−<br />

P2θ<br />

−P1<br />

θ )<br />

[ 2(<br />

3C<br />

⋅ I ) e ]<br />

()<br />

( )<br />

[ ( ) ] ⎪ ⎪<br />

2π<br />

⎧ ⎛ rω<br />

⎞⎛<br />

⎞<br />

⎫<br />

2 µ 0r<br />

⎪∫<br />

C ⎜<br />

⎟<br />

⎜<br />

⎟<br />

s1<br />

− j<br />

s2<br />

s2<br />

dθ<br />

⎪<br />

⎪ ⎝ P<br />

0<br />

2 ⎠⎝<br />

gP2<br />

⎠<br />

⎪<br />

u t = rl Re⎨<br />

⎬ (5.29)<br />

pq 2π<br />

⎪ * ⎛ rω<br />

⎞⎛<br />

µ ⎞<br />

2 0r<br />

j ω2t−<br />

P2θ<br />

+ P1θ<br />

⎪<br />

+ ∫C<br />

⎜<br />

⎜−<br />

⎟<br />

⎜<br />

⎟<br />

s1<br />

j 2 3Cs<br />

2 ⋅ I s2<br />

e dθ<br />

⎩ 0 ⎝ P2<br />

⎠⎝<br />

gP2<br />

⎠<br />

⎭<br />

Since the pole numbers <strong>of</strong> two <strong>stator</strong> <strong>winding</strong>s are dissimilar, (5.30) becomes:<br />

u pq () t = 0<br />

(5.30)<br />

The fundamental <strong>stator</strong> currents flowing in the XYZ <strong>winding</strong> set c<strong>an</strong>not induce <strong>an</strong>y<br />

voltage in the ABC <strong>winding</strong> set. Hence the two <strong>stator</strong> <strong>winding</strong> set are decoupled <strong>an</strong>d the<br />

currents flowing in one <strong>winding</strong> set c<strong>an</strong>not induce voltages in the other <strong>winding</strong> set.<br />

5.2.1.5 Voltages in Rotor Loops due to the Stator Currents Flowing in the ABC<br />

Winding Set. Since the number <strong>of</strong> rotor bars is N , the rotor equivalent circuit is<br />

r<br />

composed <strong>of</strong> N rotor loops. The <strong>winding</strong> distribution <strong>of</strong> the rotor is rich in harmonic<br />

r<br />

components. The th<br />

i rotor loop <strong>winding</strong> distribution is expressed in the rotor reference<br />

frame as:<br />

C<br />

Ri<br />

'<br />

'<br />

k − jk θ −(<br />

i−1)<br />

( θ ) C e<br />

[ α r<br />

=<br />

]<br />

∑ R ⋅<br />

(5.31)<br />

k<br />

201

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