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To understand (and optimize) a circuit for wireless charging a bit better, I tried to simulate the tx/rx coils.

There is a ferrite below/above the tx/rx coil. The peak-peak current is ca. 5A (measured). The tx coil has 5 windings the rx coil has 20 windings.

What I'm primarily interested in is the total current in the rx coil.

Secondarily about the losses in the copper plane close to it (not visible yet)

Is there a reason I could not simulate this with FEMM?

To simulate the rx coil, I tried to follow the idea of the tube example and created a circuit with 0 amps, which allows me to specify the windings. But this leads to a total current of zero amps (I assume I did something wrong). At the moment the rx coil seems to have no influence on the magnetic field (which is expected because the reported current is zero). If anyone could give me a hint where I probably went wrong this would be helpful.

axisymmetric coil simulation

The simulation is axisymmetric (left border is the axis) and the two green squares are just green marked to show where the rx (top) and tx (bottom) coils are.

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  • \$\begingroup\$ If the set-up of the experiment is easier than learning FEMM, set up the experiment. Once you have some experimental data, try simulating your experiment in FEMM. Compare your results. \$\endgroup\$ – Greetings Feb 25 '16 at 19:34
  • \$\begingroup\$ I already did that and my result does not match the simulation at all (because there is actually a substantial current flowing, even without any additional passive/active components). So either this is not possible in FEMM, or I did something wrong. In both cases this means I don't understand FEMM enough. \$\endgroup\$ – Freya Thor Feb 25 '16 at 20:27

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