Hi all,

I am using an ideal transformer model that uses the following 2 familiar eqns:

V1 = L1 dI1/dt + MdI2/dt
V2 = L2 dI2/dt + MdI1/dt

where M = k *sqrt(L1*L2), k = coeff of coupling, L1 = self inductance of primary and L2 = self inductance of secondary windings. Here k = 1, i.e. perfect coupling.

The only realistic effect I wish to add to this simple model is the leakage i.e.realistic coupling.
I  have seen  the exact equiv model which uses leakage inductances. But the problem is it is hard to know the values of these leakage inductances and the mutual inductance values. (This might sound a bit non-tech though).

What I am looking for is to use the same eqn for M as above but have a variable k, that is a model for k. I couldnt find any, except one paper that plots the k vs permeability. I am having doubts whether it is at all making sense now!!  :-/

Thnx!
Rajdeep