Comparative study of series-series and series-parallel topology for long track EV charging application

Loosely coupled inductive power transfer (IPT) systems have recently gained worldwide attention for electric vehicle (EV) battery charging. EV batteries have mainly two charging stages: constant voltage charging and constant current charging stage. 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 have shown 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, same topology can be utilized efficiently for EV charging in all the stages. Moreover a detailed comparison of series-series and series- parallel topology has been presented with intention of showing that Series-Series topology represents the best choice for IPT system among the two.