Zero‐current switching series loaded resonant converter insensitive to resonant component tolerance for battery charger

This study proposes an electric vehicle (EV) battery charger with a fixed frequency zero‐current‐switching (ZCS) series loaded resonant converter (SRC). Owing to the proposed fixed frequency operation the SRC is capable of operating under ZCS turn on and turn off regardless of voltage variation or load variation, and the magnetic components and the electromagnetic interference (EMI) filters can be optimised. The proposed battery charger has minimum component count, which makes it possible to achieve low cost and high reliability. Also, it is insensitive to resonant component tolerances and therefore suitable for high volume manufacturing. Experimental results are provided from a 3.3 kW prototype which was built for 2011 Future Energy Challenge Competition.