Distributed Control and Power Management Strategy for Parallel Bidirectional Power Converters in Hybrid Microgrids

This paper presents a new approach of distributed coordinated control for multiple interlinking converters (ILCs) to regulate the power flow across the hybrid AC/DC microgrid composed of AC and DC sub-microgrids (SMGs). These SMGs are linked together by multiple parallel ILCs that are operated as bidirectional power converters. The proposed control system not only allows reliable management and control of the power flow between SMGs but also regulates the DC voltage for the DC SMGs as part of the process. One of the key gains of this structure is the mitigation of the circulating current that results from the parallel operation of the converters. Although the circulating current is more present at the AC side, it can also exist on the DC side. At the AC side, this is achieved through the implementation of the d-q-0 axis control strategy. The presented outer control loop is a modified arrangement that could not only ensure accurate power sharing but also suppress the circulating current at the DC side.