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Hi all,
I'm trying to simulate a Piezoelectric transformer using the piezoelectric devices physics.
My structure is quite simple:
it's a thin circular membrane of piezoelectric material thick 1um (AlN), with upper concentric electrodes for primary and secondary (inner circle is the primary while the secondary electrode sorrounds the primary electrode).
Under the AlN membrane there's silicon thick 4um
I run the eingenfrequency study step in order to find resonant frequencies, but when I run frequency domain study step, in a small range of the chosen resonance, I get the error: "Failed to find a solution. The relative error is greater than the relative tolerance".
As the problem has a cylindrical simmetry, this model is set in 2D-Axysimmetric

- I have to say that I get this error when the frequency is extremely close to the resonant frequency.
- I have inserted damping and losses for all materials, thus getting a finite quality factor (so the problem is not related to undamped response)
- I ve tried an extremely fine mesh
- I ve tried to change solver parameters (although i m not an expert in solvers) and this seems to change a little the frequency where I get the error (since the Q is around 4000, I've set a 100Hz frequency step), but at the end I always get the error.
- I ve read all forum discussions about this error, but nothing seems to help me.
- If I change the radius of the structure from about 500um to 50um, I do not get the error, furthermore the simulation is faster!

How can I resolve this error?

Thanks in advance!

Antonio