Enhancing Misalignment Tolerance in IPT System to Maintain Stable Transmission Power and Improve Efficiency for Battery Charging

Abstract

This paper proposes an inductive power transfer (IPT) system to maintain stable power transfer and improve efficiency for battery charging performance across a wide range of coupling coefficient variations. The proposed IPT system uses series-series (S-S) and series-inductor-capacitor-inductor (S-LCL) compensation. In both compensation configurations, the rectifier operates in half-bridge (HB) and full-bridge (FB) modes. By using the correct switching pattern between compensation networks and the rectifier, four transfer power-coupling coefficient (P-k) curves are created. A 400 W prototype simulated in MATLAB demonstrates that, with the proposed method, output power fluctuation is limited to only 3% for coupling coefficients varying from 0.1 to 0.4, with system efficiency ranging from 80% to 95.9%. Compared to other methods, the proposed structure provides stable power transfer over an ultra-wide coupling variation and does not require special coil design, clamp circuit design, or complex control.