Rectangular spiral coils are easier to implement in wireless power transfer (WPT) applications than circular spirals. Despite this fact, research into mutual coupling between rectangular spiral coils is insufficient. In this study, a new analytical model of mutual coupling is proposed, which converts a complex multi-turn rectangular spiral coil into a single-turn rectangular coil, simplifying calculation of the self-and mutual inductances. The mutual coupling between two different arbitrarily sized rectangular spiral coils with lateral misalignment and the rectangular cross-sections can be described accurately using this model. A series of experiments is carried out, the results of which agree well with the results of calculations. Finally, the effect of the number of turns in a coil on the coupling coefficient is discussed in order to determine the recommended number of turns. This research provides an effective tool for the design of a WPT system.

An analytic model to calculate the mutual coupling between two misaligned rectangular coils with a wide range of aspect ratios of rectangular cross-section is proposed. The model can analyze all possible layouts of two parallel rectangular coils including coaxial alignment, lateral misalignment, rotational misalignment, and combinations of them. The effects of misalignments, geometry, and cross-sections of rectangular coils are addressed by a single mathematical expression. An experimental setup has been built in order to validate the analytical calculation. Theoretical and experimental results are then compared to verify the effectiveness of the proposed model.

Rectangular coils are widely used in inductive power transfer (IPT), and the self-and mutual inductances of them are key system parameters. However, the study of the rectangular coil is not enough. In this study, a series of unified analytical formulae for the self-and mutual inductance calculations of a variety of rectangular coils including filamentary coils, pancake coils and thin-or thick-walled solenoids are presented. Various positions of the rectangular coils above are discussed, and the mutual inductance formulae in the case of co-axis, co-plane, misalignment and even overlapping are given. Finally, the experimental measurements are carried out on various types of rectangular coils. The experimental results agree well with the calculated ones, which indicate the effectiveness of the proposed method. Therefore, this study provides an interesting tool for designing the transceiver of rectangular coils in IPT system.

In the bipolar (multiple) receiver inductive power transfer (IPT) system, the delivered power sharply drops with detuning due to the coupling between the two receiver coils. As a remedy to this problem, a new self-decoupled model of bipolar receiver by adding decoupling coils (sub-coils) to the receiver coils is proposed. First, the IPT system topology with a bipolar receiver has been analysed. Then, the self-decoupled model of bipolar receiver has been built. Furthermore, a quantitative calculation model of decoupling coils has been given. Finally, a series of IPT system comparison experiments for a single receiver, a bipolar receiver, and the decoupled bipolar receivers by using overlap, and the presented method are carried out separately. The results show that the presented self-decoupled model of bipolar receiver can effectively overcome the electromagnetic coupling between the dual receiver coils on the system resonance. The results further verified that the presented model is also suitable for the case with core plates.