Modeling and analysis on ring-type piezoelectric transformer

In this paper, an electromechanical model for ring-type piezoelectric transformer (PT) has been proposed based on Hamilton´s principle. To establish the model, vibration characteristics of the piezoelectric ring with free boundary conditions are analyzed in advance. Based on the vibration analysis results of the piezoelectric ring, operating frequency and vibration mode of the PT are chosen. Then, an electromechanical model for the PT was obtained, which can be used to simulate the coupled electromechanical system for the transformer, such as voltage step-up ratio, input impedance, output impedance, input power, output power, and efficiency. Thus, the optimal load resistance and the maximum efficiency for the PT will be introduced in this paper.