A multi-purpose interlinking converter control for multiple hybrid AC/DC microgrid operations

This paper presents a multi-purpose interlinking converter control design along with a simplified centralized multi-microgrid operation controller (MMOC) to achieve smooth and coordinated operations among multiple hybrid AC/DC microgrids with electric vehicle-energy storage systems (EV-ESSs). The primary purpose of the multi-microgrid operation is to share required active/reactive power among multiple microgrids. In order to achieve this objective interlinking converters of each microgrid is designed with embedded droop controllers. The conventional droop controllers are replaced with proportional-derivative (PD) compensated droop controllers. The PD compensated droop controller ensures proper damping and avoids the limitations of power sharing accuracy associated with the conventional droop controllers during islanded to multi-microgrid mode transition. A simplified centralized MMOC has been designed to control the initiation and the termination period of the multi-microgrid operation. The MMOC also generates necessary reference signals for the interlinking converters to achieve successful multi-microgrid operation among multiple hybrid AC/DC microgrids. Two islanded hybrid AC/DC microgrids are designed in MATLAB/SIMULINK environment based on N44 and N05 buildings in Griffith University, Australia. The PD compensated droop method has been embedded into the interlinking voltage source inverter (VSI) controllers of each microgrids. Simulation has been carried out for islanded mode, multi-microgrid operational mode and the transition between these two modes under variable loading and three-phase fault condition. All the simulation results show that the designed controller provides superior and robust performance for variable scenarios.