Enumeration and Analysis of DC-DC Converter Implementations Based on Piezoelectric Resonators

Demand for power electronics with smaller volume, lighter weight, and lower cost will eventually require new converter energy storage technologies with fundamentally higher power density and efficiency limits. This motivates investigation into piezoelectric resonators (PRs), which offer very high power density and efficiency capabilities and significantly improved scaling properties compared to magnetics. PRs have been used in power conversion previously, but the realm of possible converter implementations using only PRs for energy storage has seen little exploration. In this work, we enumerate and evaluate dc-dc converter topologies and switching sequences that best utilize a PR as the only energy storage component, and that enable low-loss resonant "soft charging" of the PR's input capacitance and voltage regulation capability. To compare these implementations, we present analysis techniques for their operation and periodic steady state solutions considering practical constraints. In addition, we provide useful techniques for estimating PR utilization and efficiency, which we validate experimentally in a 200-100 V, 25 W rated prototype. This prototype exhibits peak efficiency >99% as well as high efficiency (>96%) across a wide range of operating conditions, illustrating the promise of PR-based converters for high voltage, low power applications.