Hybrid Interference Field Mitigation of Dual-Rectangular Transmitter Pad for Universal Wireless Charging Area Expansion

The coordination of dual extended rectangular coils is an effective way of wireless charging area expansion for unipolar and bipolar receivers (Rxs). However, the cross-coupling field and the leakage field of the dual coils, laid out for multimodal transmission stability, inevitably interfere with system performance and external objects. This article presents a hybrid interference field mitigation method to eliminate the cross-coupling between the dual transmitter (Tx) coils and reduce the leakage flux in the target canceling area based on the specific self-decoupling (SD) and active-shielding (AS) coil design. Based on the field distribution characteristics, a planar SD coil, integrated into the Tx pad, is designed with the same-direction current of the Tx coils to couple with the adjacent Tx coils to neutralize the cross-coupling, which fully utilizes the emptiness of the overlapped Tx coils. Ulteriorly, to cancel the leakage fields outside the large charging area while minimizing the impact on transmission coupling, an AS coil with dual-objective windings is segmented to suit the Txs under different excitation modes. The mitigation coils are sequentially worked out by a simulation-based study for optimized shielding and decoupling with reduced impacts on transmission performance. Finally, a dual-rectangular Tx Pad-based WPT prototype with the designed SD and AS coils is established, and the experimental results show the effectiveness of this method.