an investigation of dual stator winding induction machines

B = B + B
(2.1)
dual
ABC
XYZ
where, B ABC is the peak value of the flux density of the ABC winding set and B XYZ is the
peak value of the flux density of the XYZ winding set. It is claimed that since the peak
value occurs infrequently, this result will be too conservative [2.2].
The second approach defines the combined magnetic loading as:
B = B + B
(2.2)
dual
2
ABC
2
XYZ
It is found from the results shown in [2.2] that the combined flux density by using
second approach will be much less than the value obtained from the first one.
The last evaluation method is called a new generalized method. This method is based
on the idea of the conventional induction machine, in which the magnetic loading is
evaluated by the mean absolute flux per pole, the proposed generalized definition is:
1
B = lim
T →∞
T
T
∫ ∫
0
1
2π
2π
0
B
( θ )
dθdt
The magnetic fields in the dual stator-winding machine can be written as:
( ω t − p θ ) + B cos(
ω t − θ + γ )
= B1
1 1 2 2 2
48
(2.3)
B cos p
(2.4)
where, B 1,
ω 1 and p 1 are the magnitude of flux density, electric speed and pole pair
number of the ABC winding set respectively; B 2 , ω 2 and p 2 are the magnitude of flux
density, electric speed and pole pair number of the XYZ winding set respectively; θ is
the stator angle and γ is the shifted angle between ABC winding and XYZ winding.
If the magnetic field of dual stator-winding machine is referred to the rotor reference
frame, the expression for field is:
( ω t − p φ)
+ B cos(
ω t − φ + γ )
r cos p
(2.5)
B = B1
s1
1 2 s2
2