Theory Of The Piezoelectric Transformer Design And Experimental Study

Comparing with conventional electromagnetic transformer, piezoelectric transformer has many advantages such as compact volume, high step-up ratio, non-flammability and none-electromagnetic pollution, which is an indispensable part in the electronic information system. However, the inherent shortcoming of piezoelectric transformer hinders its further development. The major problems include: (1) the development and design of the piezoelectric transformer involve in lots of theoretic aspects including the design of material, dimension, electrode and circuit; (2) it is hard to harvest high voltage enhancement ratio and high-power output simultaneously; (3) the operation of the piezoelectric transformer is strongly dependent on the resonance frequency, which leads to the difficulty in the design of driving circuit.In order to resolve the above problems, the model of equivalent circuit for the analysis of piezoelectric transformer has been constructed. Based on this model, a novel radial vibration mode piezoelectric transformer has been designed, fabricated and characterized. The driving circuit for the piezoelectric transformer has also been attempted.In this thesis, following aspects have been focused on:(1) According to the piezoelectric theory and wave equation, the physical equivalent circuit model of the latest invented radial vibration mode piezoelectric transformer was derived; In the case of former physical equivalent circuit model (Rosen type) piezoelectric transformer, a novel physical equivalent circuit model with multilayer structure was discussed.(2) Employing instant dry insulation glue as well as electric conductive glue, fabrication technique for radial vibration piezoelectric transformer was investigated. And a piezoelectric transformer with multilayer structure was obtained.(3) The characterization of functional parameters and performance of the piezoelectric transformer was carried out. The equivalent circuit parameters of R, L, C, f, C_d1, C_d2, load characteristic curve and frequency characteristic curve of step-up...