Cascaded Primary-Side-Only Control of a compact 2 MHz 500 W Wireless Power Transfer System

Abstract:
In this paper, we present the integration of an innovative control strategy implemented solely on the primary side of a 2 MHz Wireless Power Transfer (WPT) system. This system transfers 500 W with a power density of 25 W/cm2 and has a peak efficiency of 92.8 %. The control technology uses a cascaded design where the fast inner control loop is for safety functions and the outer control loop provides a constant output voltage. The control operates without communication between the primary and secondary sides, which has the advantage of eliminating the need for a controller on the compact secondary side, saving space and cost. This method handles not only high-frequency power transfer, but also offers promising controlling performance.