Design of High-Performance Piezoelectric Transformer-Based DC-DC Converters

Abstract

Piezoelectric transformers (PTs) are a promising energy storage alternative for power converter miniaturization. PTs offer galvanic isolation and voltage transformation like traditional magnetic transformers, but have more advantageous power scaling properties at low volumes. Despite these advantages, most attempts at magnetic-less PT-based dc-dc converters have limited whole-converter efficiencies. These attempts typically rely on standard resonant converter topologies not designed to effectively utilize PTs, along with off-the-shelf PTs not optimized for dc-dc power conversion.

In this thesis, we propose a two-pronged approach at designing high-efficiency, high-power-density PT-based converters: (1) circuit-level design strategies and (2) component-level design strategies to optimize PT components for power conversion. At the circuit level, we select high-efficiency topologies and switching sequences that most efficiently utilize PTs as sole energy storage components in dc-dc converters. At the component-level, we present geometry conditions that can aid designers in achieving PT components with both high efficiency and high power density. The strategies and analyses presented in this thesis are validated through simulation of an example PT-based converter design.