Hybrid multi‐DC–AC MG based on multilevel interlinking converter

Abstract

This study presents a multilevel interlinking converter (IC) topology to form a hybrid multi-DC–AC microgrid (MG) with an improved control system. The proposed topology provides stable DC voltage levels to link different DC MGs. Furthermore, without using any additional DC–DC converters to establish multi-DC–AC MG, the number and rating of required components are reduced. The IC performs multi-task operations including inverter-based, rectifier-based and DC–DC buck–boost-based roles in hybrid multi-DC–AC system, using a modified control strategy. A simple complementary control has been applied to keep the voltage of DC links stable instead of using other components. The proposed system improves the quality of AC-side waveforms with the lower size of filters and reduces the DC-side voltage transients compared with conventional bridge-type converters. Simulation results using PSCAD/EMTDC software and experimental result are presented to validate the effectiveness and advantages of the proposed configuration in the grid-connected mode.