Highly Integrated Ultra-Compact Three-Port Converter Systems for Automotive Applications

Abstract:
Due to the enormous cost pressure in the development of automotive power electronic systems, a high degree of integration on a system level and cost-effective production of the individual power components are an absolute must in order to develop competitive products. This means that only converter topologies can be considered that use the built-in power components as efficiently as possible, but at the same time only require components that can be manufactured in a particularly cost-effective way. Such a topology is introduced in the following, which uses a single transformer to enable power flow between three isolated voltage buses, which are commonly found in today’s electric vehicles (the output of a non-isolated single-phase PFC rectifier, the high-voltage battery, and the low-voltage battery). The presented three-port DC/DC converter topology is particularly cheap to implement in hardware, since all magnetic components can be built with PCB-integrated windings, which makes them more cost-effective to manufacture than conventional wire-wound windings. Furthermore, to use PCB-winding inductors efficiently, the so-called compensating fringingfield concept is employed, which allows for reducing the high-frequency conduction losses of PCB-windings significantly. The performance of the topology is finally verified by means of a 3.6 kW 500V/500V/15V hardware demonstrator, which achieves a peak efficiency of 96.6% at a power density of 16.4 kWL(exp−1).