A Piezoelectric-Resonator-Based DC–DC Converter Demonstrating 1 kW/cm Resonator Power Density

IEEE Transactions on Power Electronics · 2022 · 35 citations

• Electrical engineering
• Electronic engineering
• Engineering

Piezoelectric components hold promise for realizing power conversion with unprecedented levels of power handling density at small size scales. Dc-dc converter topologies and operating modes have recently been established for high-efficiency utilization of piezoelectrics, and strategies for piezoelectric material selection and component design have likewise been identified for high-performance power conversion. In this letter, we apply these developments to experimentally demonstrate the extraordinary power density capabilities of piezoelectrics. This 275–150 V, 12 W prototype achieves a piezoelectric resonator power handling density of 1.01 kW/cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula> at 493 kHz, greatly exceeding the densities of previous designs and validating the significant miniaturization potential of piezoelectrics for power conversion.

Evaluating Piezoelectric Materials and Vibration Modes for Power Conversion

IEEE Transactions on Power Electronics · 2021 · 53 citations

• Electronic engineering
• Materials science
• Acoustics

Piezoelectric components offer several potential advantages to power conversion including high power density and efficiency capabilities compared to magnetics at small scales. Converter architectures have been developed for efficient utilization of piezoelectrics, but without fundamental criteria for designing the piezoelectric components themselves. In this article, we derive figures of merit for the achievable efficiencies and power handling densities of piezoelectric materials and vibration modes based on realistic utilization in a power converter. These figures of merit are likewise accompanied by geometry conditions that serve as guidelines for high-efficiency high-power-density piezoelectric resonator design. We demonstrate use of these metrics to evaluate commercially available PZT and lithium niobate materials across seven vibration modes, and we validate the figures of merit and geometry conditions with numerical solutions of converter operation and experimental results. The proposed figures of merit are concluded to be highly representative metrics for the capabilities of piezoelectrics in power conversion, and these capabilities are shown to have favorable scaling properties for converter miniaturization.

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

IEEE Transactions on Power Electronics · 2020 · 71 citations

• Computer Science
• Electronic engineering
• Computer Science

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 with 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. This article is accompanied by an instructional video for selecting and analyzing PR-based dc-dc converter implementations.