Energy-efficient optimization of magnetized pavement structures for interoperability of inductive power transfer magnetic couplers in electric vehicles

Integrating inductive power transfer (IPT) systems into pavements is an effective way to address the inconvenience of charging electric vehicles (EVs), thereby promoting renewable energy use. Magnetized pavements can enhance the efficiency of wireless charging systems. However, the factor of magnetized pavements has not been considered in coil interoperability studies. This paper investigated the interoperability of four types of coupling coils commonly used in IPT systems: circular (C), rectangular (R), double D (DD), bipolar (BP). A total of sixteen kinds of groups of couplers were composed within a magnetized pavement medium. The study compared the changes in coil coupling under air and magnetized pavement mediums, explored the effects of transmission distance and offset distance on coil coupling and IPT system performance, and clarified the evaluation principle of considering interoperability from the perspective of energy loss. The results showed that magnetized pavement enhanced the coupling performance of C-C, C-R, C-DD, C-BP, R-C, R-R, and R-BP couplers, while it weakened the coupling performance of others. The sixteen kinds of couplers can be divided into three categories, three categories: Type Ⅰ (C-C, C-R, R-C, R-R) with highest coupling coefficients, Type Ⅱ couplers, represented by DD-DD, reaching coupling zero at 80 mm offset in Y-direction, and Type Ⅲ couplers, represented by DD-C, reaching zero when aligned, requiring transverse offset for energy transfer. To reduce energy loss, transmission efficiency should be the primary evaluation index when comparing interoperability. The IPT system with C-C coupler achieved the highest output power of 63.8 W, while the R-R coupler achieved the highest transmission efficiency of 69.6 %. When the R coil was used as the primary coil, the efficiency of the corresponding four couplers was generally higher than others, and interoperability was the best. In the process of wireless charging technology promotion, it is recommended to adopt R-R type couplers to promote the development of electric vehicle industry and improve the utilization of renewable energy.