2-D Modeling and Experimental Study of a Transverse-Mode Piezoelectric Transformer with Common Ground Electrodes Using a Lead-Free Ceramic

Building upon our previous work, this paper presents a two-dimensional (2D) modeling of a transverse-type rectangular piezoelectric transformer with common ground electrodes based on the Legendre Polynomial Approach (LPA), under the plane stress assumption and without neglecting the length between the primary and secondary electrodes called gap. Aiming to confirm the validated previous theoretical predictions obtained via PZT-5A ceramic, the studied device was designed, realized, and characterized from lead-free ceramic by selecting Barium Titanate (BaTiO or BT, belonging to the 4mm crystallographic point group of the tetragonal system) film in compliance with the European directive on lead (Pb) usage. Problem resolution via LPA lies in the formulation of mechanical displacement and electric potential, expanded in each region as a series of orthonormal Legendre polynomials with appropriate expressions, specifically constructed to satisfy boundary and continuity conditions, which are directly incorporated into the propagation equations through the delta function. Then, analytical results are modeled numerically using Matlab software. In addition, a three-dimensional (3D) numerical simulation of the same structure was performed by applying the Finite Element Model (FEM) using Comsol Multiphysics software. Electrical and mechanical responses were obtained. Results found from both FEM and LPA strongly match the experimental data. Finally, the proposed method enabled the detailed study, analysis, and optimization of all physical quantities and parameters within this electromechanical device, for improving its performance.