Design and Evaluation of a High-Frequency Wireless Power Transfer System with Synchronous Rectification

Abstract:
Wireless power transfer (WPT) is of critical importance in industrial environments that require sealed, contamination-free conditions. In this study, we present a high-frequency WPT system engineered to efficiently transfer power by stepping down the voltage from 400 V to 48 V at an operating frequency of 6.78 MHz within the ISM band, utilizing a series non-compensated LLC topology. An initial configuration, which employed a passive rectifier, achieved an efficiency of 90% at 390 W. To further enhance performance, the passive rectifier was replaced by a synchronous rectifier controlled by an external microcontroller, yielding an improved efficiency of 92% at 510 W and enhanced thermal performance. The optimized system is well suited for high-power, compact industrial applications where reliable and efficient wireless power transfer is essential.