Existing Coil Topologies for Inductive Power Transfer in EV Charging: A Review

With the growing share of electric vehicles (EV) in the market, the carbon footprint contributed by the automotive sector that is accounted for around one-quarter of the total, can be lessened. Nowadays, these cars are mainly being charged by plug-in conductive technology which bridges the gap of transition from internal combustion engine (ICE) vehicles to EV. However, at the same time, it poses the challenges of nonexistence of reliability, robustness and safety for the users which could be solved by adopting wireless power transfer technology (WPTT). Inductive power transfer system (IPTS) implements WPTT infrastructure for EV charging whose efficiency mainly dependent on coil design. Therefore, this review paper aims to summarize nine magnetic pads such as: Circular (CP), Solenoid (SP), Double-D (DDP), Double-D Circular (DDC), Double-D Quadrature (DDQP), Quad-D Quadrature (QDQ), Bipolar (BP), Tripolar (TPP) and Triple Quadrature (TQP). It enlists the overview of their classification, important parameters, flux patterns, guidelines of standardization bodies, design of coils, advantages, magnetic coupling coefficient (MCC), coordination with other pads, evaluation of these pads based on performance parameters, cost, drawbacks, applications, operation under misalignment, leakage flux and their power transfer capability. Moreover, the comparison table of above-mentioned pads not only highlights their key features but also their limitations which can be beneficial for future research work.