Comparative study of Series-Series and Series-Parallel compensation topologies for electric vehicle charging

Loosely coupled inductive power transfer (IPT) systems have recently gained enormous attention for electric vehicle (EV) battery charging. For EV battery charging, a constant-current source is required. Numerous published papers suggest that the secondary of loosely coupled IPT systems, if series compensated, can act as constant-voltage source; and, if parallel compensated, it can act as constant-current source. In this paper, the authors prove that both series as well as parallel compensated secondary can act as constant-current source as well as a constant-voltage source, depending on the nature of power supply. Hence, either of the topological options can be utilized efficiently for EV charging. The authors intend to present the work for the case where primary is in the form of a long track, such as in a mono-rail or electric traction metro system. Hence, the primary is always considered to be series compensated.