Integration of a Class-E low DV/DT rectifer in a wireless power transfer system

This paper presents the integration of a Class-E rectifier into a high frequency semi-resonant inductive power transfer system. The rectifier is used to rectify the 5.56 MHz ac output of the resonant receiving coil. End to end efficiency's exceeding 69 % are demonstrated while transferring 120 W with 30 cm coil spacing. Rectifier topologies were reviewed with their applicability to high frequency resonant IPT as a focus. A voltage driven series inductor low dv/dt resonant Class-E rectifier was selected for integration into an existing inductive power transfer system. System and rectifier efficiency is shown at 30 cm and 40 cm coil separation. Rectifier efficiency is estimated as 90.9% on the basis of the loss in overall system efficiency when using the rectifier.