Preliminary investigation on contactless energy transfer for electric vehicle battery recharging

Contactless energy transfer systems (CETSs) take electric energy from the mains and deliver it to an electric load without any wired connection between them. CETSs are receiving much attention in recent days for their numerous benefits, especially in recharging the batteries of the electric vehicles. After reviewing structure and key performance factors of a CETS and discussing the technologies enabling the contactless energy transfer, the paper focuses on the inductive CETSs. The two basic topologies of the inductive CETSs for short-range and mid-range energy transfer are examined and the equations describing their performance factors are formulated. From the equations, influence of the parameters on the performance of the CETSs is derived. At last, the recently proposed four-coil CETS topology is examined.