Wireless Power Transfer Losses Redefined by C0G Capacitor

Technology of resonant capacitors generally used in wireless power transfer system (WPTS) are commonly polypropylene film capacitors. Although it provides many interesting features on temperature, ESL value, energy density, self-reparation, etc... Their equivalent series resistance (ESR) induce important losses higher than 30% of total losses in WPTS with power higher than kW. Multilayer ceramic C0G capacitor show very low ESR allowing to divide losses by more than ten compared to film capacitors. This article proposes the use of C0G capacitor as an alternative of film capacitor for high power, and propose solutions on pcb design to improve C0G pcb performances for high power applications.