Modeling and Analysis of Four-Port DC-DC Converter

During recent past, DC natured electrical networks such as a DC micro-grid have received significant attention over their conventional AC driven counterparts. An increasing interest in the renewable, clean, and sustainable power generating sources, natively DC energy storage, and semi-conductor technological advancements led large number of DC equipment are behind this ever-increasing interest in the DC natured electrical networks. Interfacing seems necessary in an electrical network to establish the compatibility between different possible voltage levels available at the generation, energy storage, and loads. Multiport DC-DC converter (MPC) based interfacing is superior over the conventional two port single-input single-output interfacing structure. Motivated by these, this article considers a four-port DC-DC converter (FPC) design, which accommodates fuel cell (FC), battery bank (BB), solar photovoltaic (SPV) system, and DC load at its ports. The presented work formulates linear state-space model of the considered FPC. In this formulation, small signal modeling of the FPC is done from the detailed model of the latter. The process of obtaining a small signal model requires linearization of corresponding large signal models. Finally, the work compares large, and small signal responses of states of state-space model of the FPC.