eem2am
Banned
Hello,
I am confused about the comparative performance of SEPICs with coupled inductors, compared with SEPICs with uncoupled inductors....
..can any reader shed any light here......
if a SEPIC converter uses coupled 1:1 inductors, then it behaves the same as does a SEPIC with uncoupled inductors of twice the value.
For example, consider a SEPIC with 1:1 coupled inductors (each winding measuring 250uH with the other one open)............
....then this gives the same inductor ripple current as does a SEPIC with two uncoupled inductors of value 500uH.
If you wish , you can confirm this with this LTSPice simulation:-
(-just change the inductor values and the coupling from 1 to 0, eg "K L1 L2 0" or "K L1 L2 1")
2shared - download 5V SEPIC__FORUM.asc
My question is......why is the factor of *two* involved here?
...i would have thought that the coupled inductors would appear to have *four* times the inductance of the case of uncoupled inductors.
....after all, the coupled 1:1 inductor effectively has twice the number of windings , and so that means *four* times the inductance....
So why is it that 1:1 coupled inductor SEPICs don't behave like uncoupled SEPICs with *four* times the winding inductance?
I am confused about the comparative performance of SEPICs with coupled inductors, compared with SEPICs with uncoupled inductors....
..can any reader shed any light here......
if a SEPIC converter uses coupled 1:1 inductors, then it behaves the same as does a SEPIC with uncoupled inductors of twice the value.
For example, consider a SEPIC with 1:1 coupled inductors (each winding measuring 250uH with the other one open)............
....then this gives the same inductor ripple current as does a SEPIC with two uncoupled inductors of value 500uH.
If you wish , you can confirm this with this LTSPice simulation:-
(-just change the inductor values and the coupling from 1 to 0, eg "K L1 L2 0" or "K L1 L2 1")
2shared - download 5V SEPIC__FORUM.asc
My question is......why is the factor of *two* involved here?
...i would have thought that the coupled inductors would appear to have *four* times the inductance of the case of uncoupled inductors.
....after all, the coupled 1:1 inductor effectively has twice the number of windings , and so that means *four* times the inductance....
So why is it that 1:1 coupled inductor SEPICs don't behave like uncoupled SEPICs with *four* times the winding inductance?
