STMicroelectronics A 200 W ripple-free input current PFC pre-regulator with the L6563S EVL6563S-200ZRC EVL6563S-200ZRC Data Sheet
Product codes
EVL6563S-200ZRC
AN3180
Electrical equivalent circuit models of coupled inductors and transformers
Doc ID 17273 Rev 1
33/39
Figure 26.
Model of coupled inductors with a = n
e
(a = n
e
model)
Another interesting and quite frequently used choice is a = 1. This results in a very simple
model, illustrated in
model, illustrated in
, useful for analyzing loosely coupled inductors, where L
1
-M
and L
2
-M are both positive, which happens if:
Equation 29
Note that the terminal voltages and currents are still exactly the same as those of the real
inductors.
inductors.
Figure 27.
Model of coupled inductors with a = 1 (a =1 model, or T-model)
!-V
L
L
W
W
Q
Y
W
Y
W
/
LGHDO
H
Q N /
H
N /
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
=
⎟
⎟
⎠
⎠
⎞
⎜
⎜
⎝
⎝
⎛
<
e
e
n
n
,
1
min
L
L
,
L
L
min
k
1
2
2
1
!-V
L
W
Y
W
0
/
0
L
W
Y
W
/
0