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Design Languages >> VHDL-AMS >> Flyback Transformer modeling using VHDL-AMS
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Message started by Sylvester on Jun 26^th, 2012, 7:35am

Title: Flyback Transformer modeling using VHDL-AMS
Post by Sylvester on Jun 26^th, 2012, 7:35am

Hi everyone,

i have some kind of a problem. At the moment i'm trying to model a flyback transformer with VHDL-AMS, simulating it with CADENCE AMS-Designer.
I allready have a model of a "normal" transformer using a transition from electrical to magnetic domain. So i have a model for a inductor, a model of a core without effects of saturation and a model of the air gap in the core. This would be enough for a first shot, as it would work as intended.
i have two equations modeling the inductor (n is the number of windings):

Code:

mmf == n*i;
v == r_wind*i - n*flux'DOT;

the core and the airgap are modeled over the equation: mmf == reluctance * flux;
I have a inductor on the primary side of the transformer and one inductor on the secondary side of the transformer.
I apply a voltage on the primary side of the transformer, therefore i see a linear rise of current, magnetic flux and mmf, as it should be.
on secondary side i see a magnetic flux (because magnetic ports of both sides are connected), but mmf on secondary side is 0, because current on this side is zero. (because mmf == n*i)
I want the secondary's side mmf to rise the same way as mmf on primary side and then create a current on this side. I tried a lot of things, but no matter what i do, mmf is always zero.
Anybody seeing a solution for the problem?

i hope you understand my problem. if everything isn't clear, just ask.

i would be happy if you could help me

Greetings from Munich, Germany,
Sylvester