Design Calculator and Performance Analyzer Software Tool for Step-down Piezoelectric Transformer

Abstract

Piezoelectric is a versatile material used in sensors and actuators. Piezoelectric transformers (PTs) convert electrical energy into electric energy by using mechanical vibration energy. Both converse (actuator) and direct (sensor) piezoelectric effects are utilized simultaneously in Piezoelectric transformers operation. On applying voltage, the input of the transformer works as an actuator, which generates vibration in the output structure (sensor) thus stepping up/down the input voltage. These are typically manufactured using piezoelectric ceramic materials that vibrate in the resonance frequency range. Piezoelectric transformers are very energy efficient when operated in the resonance frequency range (between resonance and anti-resonance frequencies). With appropriate designs, it is possible to step up and step down the voltage between the input and output of the piezoelectric transformer, without making use of wires or any magnetic materials. The purpose of this thesis is to develop a step-down piezoelectric transformer design software as per user requirements. The software tool first generates the estimated different electrical circuit and mechanical dimensions parameters for initial analysis as per user-supplied data. Then using SPICE and FEM analysis results, the software can generate a prototype step-down piezoelectric transformer design for prototyping. The prototype design experimental data is then used by the software tool to analyze the design parameters as per the user requirements. The proposed design calculator is developed using MATLAB. Analytical equations are implemented in MATLAB which generates the piezoelectric transformer equivalent circuit and structural dimensions. The equivalent circuit is then simulated using LTSPICE and SIMULINK through the MATLAB interface. After design iterations and improvement, the structural parameters are used to perform FEM analysis of the PT in COMSOL. The comparison of design, SPICE and FEM simulation is done in the MATLAB software. After prototyping, the experimental resonance frequency, voltage and power data are compared with the design and simulation result for optimization of the design. All steps are performed in this thesis for the validation of the designed software tool.