Piezoelectric Resonator Second Harmonic Cancellation in Class Φ2 Inverters
Conference
COMPEL
Abstract
Compared to inductors, piezoelectric resonators exhibit many advantages for high-frequency power conversion, including higher power density and quality factor. Topologies utilizing piezoelectric resonators as their only energy storage element have been enumerated and demonstrated with high-efficiency DC-DC converters. However, other circuit topologies that are not “magnetic-less” can also benefit from integrating piezoelectric resonators into their design. This paper analyzes how the Class Φ2 resonant inverter can utilize a piezoelectric resonator for its second harmonic cancellation branch. We detail the resonator design considerations for this application, discuss the advantages of using a resonator instead of a discrete inductor and capacitor, and present a prototype Class Φ2 inverter with a lithium niobate resonator for experimental verification. The prototype Φ2 inverter delivers up to 122 W of RF power at a drain efficiency of 95.4% with only approximately 300mW of power loss in the second harmonic cancellation piezoelectric resonator.
