Fixed frequency series loaded resonant converter based battery charger which is insensitive to resonant component tolerances

This paper proposes an EV battery charger with a fixed frequency operated series loaded resonant converter(SRC). Due to the proposed fixed frequency operation the SRC is operated under ZCS turn on and turn off regardless of load condition, and the magnetic components and the EMI filters can be optimized. 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 3.3kW prototype which was built for 2011 Future Energy Challenge Competition.