PROBLEM
- Rosen Transformer 25 mm x 8 mm
x 2.2 mm t

GEOMETRY/DRAWING
Analysis of a piezoelectric transformer.
The model is 3D, and two analyses will be used: modal,
to determine the resonance frequency of the transformer, and harmonic,
to determine
the gain of the transformer at resonance.
A piezoelectric transformer is a device that operates at resonance and that makes
use of both direct and converse piezoelectric effects. In short, a low-voltage
signal is applied at the input section in order to excite the mechanical resonance
of the transformer. The stresses induced by the resonance effect produce charges
at the electrodes of the output section. As a result, the input voltage is transformed,
either into a higher (step-up transformer) or lower voltage (step-down transformer).
The transformer modeled in this tutorial is a so-called Rosen-type
(from the name of the inventor), and it is somewhat simplified.
It operates
in a λ/2
(half-wavelength) longitudinal vibration mode. The dimensions used
for the geometry are shown (in mm) in the following figure.
The material se-lected for this problem is PZT4
for both input and output sections. The electrodes are shown
in the next figure.
MATERIAL
ASSIGMENT
Piezoelectric Materials
Data -> Materials -> Piezoelectric -> PZT4 -> Assign
-> Pick Volumes
Assign material PZT4 to the two volumes. Note that the definition
of the material PZT4 includes losses. You can verify the loss angles
by clicking on the Losses tab. The values Delta_m, Delta_p, and
Delta_d correspond to the loss angle for the mechanical, piezoelectric
and dielectric tensors, respectively.
When this is done, the material assignment should
be similar to the following image (you can obtain this by selecting,
on any material window, the option Draw | All materials).
Click Draw -> All materials -> Check the
material is assigned as PZT4
