As a further step to go forward to a more improved performance on the inductive power transfer system (IPTS) for road‐powered electric vehicles (RPEVs), an ultra‐slim S‐type power supply rail, which has a width of only 4 cm, is explained in this chapter. The cross‐section of the core has a thin S‐shape, and a vertical‐wound multiturn coil is displaced inside the core. Therefore, this design provides a very slim power supply rail, which is crucial for the commercialization of RPEVs. The construction of roadway infrastructure, which is responsible for more than 80% of the total deployment cost for RPEVs, can be much easier when the width of the power supply rail is so small. To increase portability and to minimize construction time, a foldable power supply module is also proposed in which flexible power cables connect each foldable power supply module such that no connectors are needed during deployment. An effective winding method for minimizing cable length is proposed, and an optimum core thickness of the proposed power supply rail is determined by FEA simulations and verified by a prototype power supply module. By virtue of the ultra‐slim shape, a large lateral displacement of 30 cm at an airgap of 20 cm was experimentally obtained, which is 6 cm larger than that of the I‐type power supply rail. In addition to the larger lateral displacement, it is estimated that the S‐type one has a lower EMF than the I‐type one because the width of the S‐type one is narrower than that of the I‐type one. The maximum efficiency, excluding the inverter, was 91% and the pick‐up power was 22 kW.

This chapter is written from the paper by S.Y. Choi, B.W. Gu, S.Y. Jeong, G.C. Lim, and Chun T. Rim, “Ultra slim S‐type power supply rails for road powered electric vehicles,” IEEE Trans. on Power Electronics, vol. 30, no. 11, pp. 6456–6468, November 2015. Readers will be able to see not only how to make the power supply rail slim but also how important the modularity design is to carry and deploy.