Tiny Power Box - Exploiting Multiport Series Resonant Topologies for Very High Power Density Onboard Chargers

Growing expectations of modern onboard chargers for bidirectional power, galvanic isolation and additional low voltage output(s) leads to ever-increasing part count and complexity. Nevertheless, this paper shows that very high power density can still be achieved with a multiport series resonant topology. Close to 4 kW/dm3 (excl. housing) is achieved for 7kW and 11kW applications with a charging efficiency >97% while meeting most safety and EMI standards resulting in up to 3.1 kW/dm3 (incl. housing) when liquid cooling is used. An overview of the proposed topology and optimization approach is given followed by a description of both prototypes with comparison to state of the art.