A Novel Hybrid Shielding Method With Single-Source Active Topology and Efficiency Stability for Wireless Power Transfer

Single shielding methods, especially single-active and single-ferrite, are known to suffer from insufficient comprehensive performance in wireless power transfer (WPT) systems. To render the two single methods complement each other, a novel hybrid shielding method along with a parameter optimization strategy (POS) is proposed in this article. The hybrid shielding system is composed of single-source topology-integrated active suppression coils and adjustable ferrites. Two planar suppression coils are integrated into the compensation topology without an additional source. The suppression coil generates canceling flux and compensating flux, and its component directions are opposite to the leakage flux of the ferrite pad and consistent with the main flux magnetic circuit, respectively. The principles of the POS are explained and discussed based on the analysis of magnetic field and circuit theory. A 0.8 kW/85 kHz full-scale WPT prototype based on the proposed shielding method is fabricated, and its performance is experimentally verified. With the transmission efficiency not less than 91.5%, the proposed method improves the shielding performance by 23.47% on the transmitting side, 24.67% on the receiving side, and 23.2% on the lateral side, respectively.