Design, analysis and control of a magnetically-coupled multi-port multi-operation-mode residential micro-grid

This paper proposes topology of a magnetically coupled residential micro-grid consisting of a multi-port dc-dc converter and a single phase grid-connected bi-directional inverter. It integrates photovoltaic (PV) and fuel cell energies to supply the residential load via a common high-voltage dc bus linked to a single phase bidirectional inverter. A battery is used to store the surplus energy of the system and stabilize the bus voltage of the fuel cell port. The multi-port converter includes a three port phase shift converter for integrating renewable sources, a bidirectional buck-boost converter for charging and discharging the battery and an interleaved boost converter for boosting the PV voltage and maximum power point tracking. Using interleaved topology has reduced the effects of both high frequency current ripple and low frequency voltage ripple propagated from inverter on the maximum power point tracking (MPPT) performance. The steady state operation and control strategy of the proposed micro-grid are discussed and simulation results are presented.