Analyses of the Heat Dissipated by Losses in a Piezoelectric Transformer

In this paper, a new approach to the thermal management of piezoelectric transformers is proposed. Starting from the electromechanical equations, including mechanical and dielectrical losses, and knowing the piezoelectric material characteristics, an analytical model was developed and the theoretical profile of the heat sources was deduced. To check these theoretical points of view, a thermal characterization of a Rosen-type piezoelectric transformer was done. The temperature field on the surface of the PT was measured in thermal transient steps. Knowing the specific temperature, the experimental heat sources were obtained. As expected, they are related to the square modulus of the strain or stress profiles on the one hand and to mechanical losses on the other, which confirms the theoretical results. Experimental data and calculation results are matched for several resistance loads and frequencies tested.