Design Of The Orthogonal Composite Sandwich Piezoelectric Transformers

Piezoelectric transformer and piezoelectric power transmission technology have the advantages of no electromagnetic pollution,miniaturization,high temperature breakdown,high energy conversion efficiency,high safety and easy mass production.They are widely used in liquid crystal display,high-frequency switching power supply,notebook adapters,mobile phone chargers,aerospace equipment,submarine electronic equipment,civil lighting equipment and other aspects of national defense and people’s livelihood.In the field of piezoelectric wireless power transmission,the traditional longitudinal sandwich piezoelectric transformer has a single transmission channel and cannot meet the needs of multi-dimensional power transmission and voltage transformation in some special occasions.In order to improve the ability of transform of existing longitudinal sandwich piezoelectric transformer and increase their number of transmission channels,this paper proposes a new two-dimensional/three-dimensional multi-output orthogonal composite sandwich piezoelectric transformer.The main research contents are as follows:(1)By introducing two-dimensional mechanical coupling coefficient and two-dimensional longitudinal force conversion coefficient,and using apparent elastic method and electromechanical analogy principle,the unified equivalent circuit model of in-phase and anti-phase vibration of two-dimensional orthogonal composite vibration direction converter is established.Combined with the finite element software ANSYS and experimental test results,the correctness of the equivalent circuit method is verified,and the equivalent circuit method is more concise than the original wave equation method.(2)By introducing three-dimensional mechanical coupling coefficient and three-dimensional longitudinal force conversion coefficient,and using apparent elastic method and electromechanical analogy principle,a unified equivalent circuit model of three vibration modes of three-dimensional orthogonal composite vibration direction converter is established.The equivalent circuit method results,finite element method results and experimental test results are basically consistent,which verifies the correctness of the equivalent circuit model of the three-dimensional orthogonal composite vibration direction converter.(3)Two-dimensional orthogonal composite vibration direction converter integrates power synthesis and two-dimensional vibration output.Based on this,a two-dimensional single-excitation three-output orthogonal composite sandwich piezoelectric transformer is proposed.Further,the expressions of the resonance frequency equation,the effective electromechanical coupling coefficient,the transmission transformation ratio and the transmission power ratio are obtained.The equivalent circuit method,finite element method and experimental test are used to analyze the frequency and load response of the piezoelectric transformer,which provide a theoretical basis and experimental data reference for the engineering application of this piezoelectric transformer.(4)Compared with the two-dimensional orthogonal composite vibration direction converter,the theoretical power synthesis and multi-dimensional vibration output performance of the three-dimensional orthogonal composite vibration direction converter will be more flexible and excellent.Based on this,a three-dimensional symmetric excitation four-output orthogonal composite sandwich piezoelectric transformer is proposed.Further,the expressions of the resonance frequency equation,the effective electromechanical coupling coefficient,the transmission transformation ratio and the transmission power ratio of the transformer are obtained.The equivalent circuit method,finite element method and experimental test are used to analyze the frequency response electromechanical characteristics of the piezoelectric transformer,which provides theoretical design guidance and experimental data reference for the engineering application of this piezoelectric transformer.