Single-layer piezoelectric transformers with a unique design of polarization topologies

Abstract Piezoelectric transformers (PTs) are usually designed in multilayers to obtain a large voltage transformation ratio while reducing the driving voltage. In contrast to the complex manufacturing process of multilayer PTs, this study proposes a single-layer PT that works in planar expansion mode and can achieve different step-up ratios. In this method, the topological structures of the electrode division and the polarization region are designed cleverly in piezoelectric ceramics with different shapes (i.e., rectangle and circle). Therefore, a high voltage output with different step-up ratios can be obtained under low voltage excitation. This study also discusses the working principle of the two shapes of single-layer PTs and deduces the optimal inner and outer radius ratios of circular PTs. Then, combined with three-dimensional modeling, finite element software is utilized for the multi-physics simulation of the PTs. Lastly, single-layer rectangular and circular PTs with different step-up ratios are fabricated. The actual step-up ratios and working efficiencies are measured experimentally. The experimental results are consistent with theoretical analysis and simulation data, thus verifying the feasibility of the single-layer PT design with different step-up ratios.