Circuit Model Analysis to Delineate the Significance of Load Coil in Resonant Inductively Coupled Wireless Power Transfer System

Wireless Power Transfer (WPT) via magnetic resonance coupling is gaining traction due to its robust characteristics and established efficacy. Nevertheless, controlling and enabling seamless power transfer to devices using the conventional two-coil WPT system presents significant challenges. The weak mutual coupling of the transmitter and receiver coils limits substantial power transmission. To resolve these issues, a distinctive WPT approach has been introduced that integrates an additional coil on the receiver side, creating a load coil embedded system. A comprehensive circuit model analysis of this series-series load coil embedded system is provided, drawing comparisons with the two-coil WPT system. The study delineates overall power transfer efficiency and individual load power delivery in relation to frequency and mutual coupling across various load conditions. To validate the theoretical analysis, an experimental bench setup is implemented. The empirical findings align well with the theoretical predictions derived from the equivalent circuit model. Both simulated and experimental results affirm the efficacy of this approach, providing crucial insights for the design of an effective WPT system.