An IPT System for Stable Output Power Transfer and Efficiency Improvement against Large Coupling Variations

This paper propose an inductive power transfer (IPT) system with an active rectifier to maintain the output power with minimal fluctuations over a wide range of coupling factor variations. The proposed IPT system utilizes both Series-Series ($S-S$) compensation and Inductor-Capacitor-Capacitor-Series (LCC-S) compensation. In both compensations, the rectifier operates in half-bridge $(H B)$ mode and full-bridge $(F B)$ mode, creating four operational regions of transfer power versus coupling coefficient ($P-k$). Consequently, the system can maintain a relatively stable power output under significant coupling changes. A 400 W prototype is simulated, demonstrating that the fluctuation of the output power using the proposed method is only 3% for a coupling coefficient varying from 0.1 to 0.4, and the system efficiency varies from 80% to ${9 4. 9 7 \%}$. The proposed topology does not require special coil design, clamp circuit design, and complex control.