Instead of using two individual inducotrs i want to use coupled inductor in psim. it is mentioned in psim that self inductance and coupling factor parameters for coupled inductor. how to choose that parameters ?
Raghavendran,
What is the application, if it is OK to ask ?
Or more precisely, what is the circuit you intend to simulate ?
-Sanjay
Sanjoy,
for simulating a sepic converter. instead of using two separate inductors, i want use a coupled inductor.
Raghavendran,
If I got you right, you are trying a single-core version for the circuit, of the type that has already been investigated for the Cuk converter ?
Interesting and hopeful to investigate, because if I recall right, in case of the Cuk converter this modification reduces output and input current ripples significantly, apart from the reduced cost (which follows from the reduction in number of cores) !
For coupled inductors,
M = k . [L1 . L2]1/2
Hope that helps ?
The value of coupling factor k depends on your design. Since it is a simulation at the moment, you may wish to experiment with various values. k < 0.5 progressively makes L1 and L2 like two independent (uncoupled) inductors as in the original circuit.
I would be careful if I were you in the range where the coupling factor k > 0.5. That is when the mutual inductance starts to dominate, and one may expect interesting circuit behaviour.
Good luck with the simulation...
-Sanjay
sanjoy sir,
yes sir. it is a single core version.
In literature it is given that If L1 and L2 are closely coupled, the ripple current is divided between them , and the required inductance is halved.
closely coupled means coupling factor factor is near unity?. but in simulation self inductances L1 and L2 are chosen as 1mH and if the coupling factor is chosen even as 0.001, the current reaches infinity. By choosing coupling factor as 0.0009, then only the current has some meaningful value.
Also how the coupling factor in simulation will work for hardware?.
Hi Raghavendran,
That's what I said - the adjustments is not easy as it looks.
It is a good thing that you are going for detailed simulations before any hardware design. This way at least the trial-and-errors don't cost you anything !!
Coming back to the specific case of the coupling factor, please don't overlook the fact that both currents (input and output) depend on all connected components - not the inductances alone !
Very low values of k get you to a state close to no coupling, so your original design values (which corresponded to uncoupled inductors) function reasonably.
The moment you make k any significant, this situation is disturbed. You therefore need to work out all connected capacitance and duty cycle values together with the inductance values afresh, to get meaningful results !!
There are similar effects when you couple the inductors in a Cuk converter setup.
So yes - bottom-line is: this is not easy, demands sensible effort !!
-Sanjay
Sanjoy sir,
Thank you very much for your answer and motivation sir.
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