Extending the operating limits of a bidirectional three-port DC-DC converter

This paper proposes a design of a bidirectional three-port DC-DC converter in order to extend the operating limits when the converter is used as an interface between a battery bank, a supercapacitor and a dc load. The operating limits are determined according to the maximum current on the switches and also by the thermal limit established by the junction temperature of the semiconductors. It is shown that the amplitudes of the DC voltages have a significant influence on the operating limits, which depend on the state of charge of batteries and supercapacitors. Other factors with an important influence on the operating limits are the values of the auxiliary inductances of the converter.