High efficiency insulated DC/DC boost converter for 12/42 V applications

The purpose of such an application is to boost energy stored in batteries or ultra capacitors at variable low voltages to feed a common DC bus at about 42 V for automotive embedded applications. The range of power for these applications is up to some kW (nominal power at 4 kW). In this direct proposed conversion topology, transistors MOSFET operate under soft switching conditions that is to say that this converter presented very low losses. Another advantage is presented with the HF link intermediate bus, which permits the adaptation of voltage levels thanks to new planar technology for transformers. This paper presents control strategy of the switches and HF planar transformer. Experimental results show the high efficiency obtained with this low losses structure and the very compact size of the realized converter well adapted for on-board auxiliary power voltage sources especially for automotive applications.