Volume Optimization in Si IGBT based Dual-Active-Bridge Converters

Dual-Active-Bridge (DAB) converters are able to step up/down DC voltage in a wide range by adopting medium frequency transformer (MFT) for isolating and converting voltage level. Increase in switching frequency of Si IGBTs reduces the MFT size instead it intensifies the semiconductor switching losses which leads to increase in the heatsink size. In this paper variation of heatsink volume versus frequency is compared versus MFT. MFT and heatsink volume of a 5 kW 600 to 400 V DAB converter are optimized. Obtained results show that variation of switching frequency in range 1-10 kHz increases the size of optimal heatsink by 3 times, i.e ${V_{HS,opt}} \propto \sqrt {{f_s}[kHz]} $.