Piezoelectric Transformer Power Converter With Power Factor Correction

The Piezoelectric Transformer (abbrev, PT) is an electro-mechanical device that transfers electrical energy through a mechanical vibration. The features of PT are high voltage gain, little circulating current, high power density, compact size, and no electromagnetic noise. Since it was proposed in the 1950s, PT is employed effectively in low power converter field. Recently, PT as a power device applied in power converters has become an important research area. The narrow bandwidth control method for PT power converter is researched in this thesis. Based on the platform of 150W PT power converter, the computer simulation of PFM controller, the principle analysis and design method of the main circuit and power factor correction circuit for 150W PT power converter are achieved, and the prototype is assembled and the relational experiments are implemented.The contents of this thesis are as follow:1) Through reading a large number of reference papers about PT and PT power converter all over the world, a review about development and basic knowledge of piezoelectricity material, the operation principle and electrical model of piezoelectric transformer, the research situation and applications of PT power converter is finished;2) The narrow bandwidth control operation of PT converter is proposed based on the characteristics of PT. The Input Matching Networks (abbrev, IMN) of PT power converter is introduced; the function of the IMN is proved theoretically; the design method of the IMN is put forward;3) The current control method of PT power converter is discussed and the computer simulation of close loop system is achieved;4) The design method of charge pump power factor correction (abbrev, CPPFC) for PT power converter is proposed in this thesis. The principle of different types of CPPFC circuits is analyzed; the parameters design methods are put forward; the computer simulation and experiments are implemented.