A novel design of partially magnetized pavement for wireless power transfer to electric vehicles with improved efficiency and cost saving

As electric vehicles (EVs) tend to replace conventional gasoline vehicles, efficiently charging EVs with limit energy loss is critical. One promising solution is to utilize wireless charging module embedded in the pavement for dynamic charging. The existence of pavement layer between coils was regarded as a negative impact factor for wireless power transfer (WPT) by most previous studies. However, this study proposes an innovative design of partially magnetized pavement to improve the WPT efficiency via creating a magnetized pathway through the pavement layer. The specific magnetized area and location will be varied by the particular coil design. The basic WPT system with coils in air was first simulated and the results were validated by analytical solutions and experimental results. Finite element models (FEMs) of WPT-roadway systems were then built to analyze magnetic field and WPT efficiency of new design considering different coil embedment depth, vehicle wandering, magnetic properties of pavement layer. The results revealed the advantage of the partially magnetized pavement over conventional pavement for wireless power transfer, which did provide 1.5%-13.3% improvement of charging efficiency. Such advantage from partially magnetized pavement was more significant if that surface layer above transmitting coil was thicker or the magnetized part had higher magnetic permeability. Moreover, the efficiency improvement remained effective until the vehicle lateral wander reached 0.5 m. The economic analysis showed that a high electricity cost saving was brought with limited amount of magnetic materials needed.