Dual Floating Based Three Port DC-DC Converter for EV-APM

This article proposes a new isolated three-port dc–dc converter (TPC) named dual floating dual active bridge (DAB) three-port converter. The proposed converter combines an isolated DAB converter and an interleaved nonisolated dual floating boost (DFB)converter. As the power demand of auxiliary loads in the vehicles rapidly increases due to autonomous and entertainment systems, a dual auxiliary voltage (48 and 12 V) system is introduced to mitigate the burden of high current. The high voltage gain feature of the DFB converter ensures that the operating duty remains around 0.5, reducing filter size, turn-off current, and circulating current, and increasing the power transfer capability from the high voltage side. Additionally, the lower voltage stress on the low-side switches allows for the use of switches with lower R_DS,on, reducing conduction losses. To validate the theoretical claims, a 6.1 kW, 100 kHz prototype of the proposed TPC has been built. The prototype operates with a wide HV-port voltage range of 400–840 V and a 12 V-port voltage range of 9–16 V while providing a fixed 48 V to the 48 V-port. The prototype achieves a power density of 9.14 kW/L and a peak efficiency of 96.6%.