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
Measuring transformer and coupled inductor parameters
Doc ID 17273 Rev 1
37/39
Figure 30.
Winding connections: aiding flux (left), opposing flux (right)
It is always L
A
> L
O
, therefore, as already mentioned:
Equation 32
The advantage of this method is its low sensitivity to winding resistance and to the
impedance of the wire used for connecting the windings. It is not recommended for low
values of k because in that case it would be given by the difference of two similar quantities,
and the error might be high.
impedance of the wire used for connecting the windings. It is not recommended for low
values of k because in that case it would be given by the difference of two similar quantities,
and the error might be high.
Whichever method has been used, the parameters of the equivalent circuit of
(a =
n
, assuming n is known) can be readily calculated from the third group of
with
obvious symbolism change:
Equation 33
The parameters of the equivalent circuit of
(a = n
e
, useful in case n is not known)
are given by
, here re-written for convenience:
Equation 34
!-V
/ //0
$
/
/
0
/
/
0
/ //0
2
2
1
O
A
O
A
L
L
4
L
L
k
4
L
L
M
−
=
⇒
−
=
⎪
⎪
⎪
⎩
⎪⎪
⎪
⎨
⎧
−
=
−
=
−
=
−
=
=
M
L
L
n
L
L
M
L
L
L
L
M
L
2
M
2
2
2
1
M
1
1
M
n
n
n
l
l
(
)
(
)
⎪
⎩
⎪
⎨
⎧
=
−
=
=
−
=
μ
1
2
2
b
1
1
a
L
L
with
,
L
k
1
L
L
k
L
L
k
1
L
e
n