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an investigation of dual stator winding induction machines

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5.2.2 Torque Equation<br />

The calculation <strong>of</strong> the torque components <strong>of</strong> the <strong>dual</strong> <strong>stator</strong> <strong>winding</strong> <strong>induction</strong><br />

machine is very import<strong>an</strong>t in the underst<strong>an</strong>ding <strong>of</strong> the machine. Developed torque c<strong>an</strong> be<br />

calculated at the <strong>stator</strong> surface. The general expression <strong>of</strong> the developed electromagnetic<br />

torque is defined as:<br />

2π<br />

( θ,<br />

t)<br />

⋅ B ( θ , t)<br />

dθ<br />

Te = −rl<br />

∫ J S<br />

g<br />

(5.71)<br />

where ( , t)<br />

B g<br />

0<br />

θ consists <strong>of</strong> the flux densities contributed by the currents flowing in the<br />

two <strong>stator</strong> <strong>winding</strong> sets <strong>an</strong>d the rotor currents they induce in the rotor circuit. Since the<br />

magnitudes <strong>of</strong> the harmonic flux density components are much less th<strong>an</strong> the fundamental<br />

components, only the fundamental flux densities contributed by the fundamental currents<br />

in the two <strong>stator</strong> <strong>winding</strong> set <strong>an</strong>d rotor loops are considered. Hence, the expression <strong>of</strong> the<br />

total flux density is given as :<br />

( θ t)<br />

B ( θ,<br />

t)<br />

+ B ( θ,<br />

t)<br />

+ B ( θ,<br />

t)<br />

+ B ( θ,<br />

t)<br />

Bg , 1<br />

2<br />

prp<br />

qrq<br />

= (5.72)<br />

5.2.2.1 Torque components due to Currents Flowing in the ABC <strong>winding</strong> Set. The<br />

torque component from the <strong>stator</strong> ABC <strong>winding</strong> set c<strong>an</strong> be calculated as:<br />

T<br />

e1<br />

= −rl<br />

2π<br />

∫<br />

0<br />

J<br />

1<br />

2π<br />

⎡<br />

⎢∫<br />

J1<br />

= −<br />

⎢ 0<br />

rl<br />

⎢ 2π<br />

⎢+<br />

⎢ ∫ J<br />

⎣ 0<br />

( θ,<br />

t)<br />

⋅ B ( θ,<br />

t)<br />

g<br />

dθ<br />

2π<br />

( θ,<br />

t)<br />

⋅ B ( θ,<br />

t)<br />

dθ<br />

+ J ( θ,<br />

t)<br />

⋅ B ( θ,<br />

t)<br />

1<br />

1<br />

∫<br />

2π<br />

( θ,<br />

t)<br />

⋅ B ( θ,<br />

t)<br />

dθ<br />

+ J ( θ,<br />

t)<br />

⋅ B ( θ , t)<br />

prp<br />

0<br />

1<br />

∫<br />

0<br />

1<br />

2<br />

211<br />

qrq<br />

dθ<br />

⎤<br />

⎥<br />

⎥<br />

⎥<br />

dθ<br />

⎥<br />

⎥⎦<br />

(5.73)

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