Hard- and Soft-Switched
Technical Dialogue Session
DC-DC Converters II
GaN, Phase Shift Full Bridge, Planar Transformer, High Frequency, Battery Charger, ZVS
EV on-board battery chargers must be designed to be size, weight and energy efficient. This paper highlights the need for energy efficiency over nominal load efficiency and demonstrates that energy efficiency of Phase shifted full bridge (PSFB) can be improved by reducing the ZVS range slightly. This proposed design would require low leakage inductance transformer designs. However there are practical limitations to how far leakage could be minimized with conventional transformers. Hence this paper highlights that planar transformers are necessary over conventional transformers for the proposed design in order to meet the low leakage inductance desired. Several planar winding strategies to highlight their effects on leakage inductance and associated parasitic capacitance to better optimize the proposed design for energy efficiency is also discussed. The results show compactness achieved along with efficiency improvements. Preliminary experimental results of PSFB and a comparison between the conventional and proposed planar transformer using finite element model (FEM) is presented.