Coordinated Power Management Control Strategy for Interconnected AC and DC Microgrids

Abstract

This chapter investigates the issue of active power sharing among a cluster of microgrids formed by a set of ac and dc microgrids network-interconnected through a set of interlinking converters. First, we investigate the power sharing problem for two interconnected AC/DC microgrids. An appropriate control strategy is developed to control the interlinking converter (IC) to realize proportional power sharing between ac and dc microgrids, which includes two parts: the primary outer-loop dual-droop control method along with secondary control; the inner-loop data-driven model-free adaptive voltage control. Using the proposed scheme, the interlinking converter have the ability to regulate and restore the dc terminal voltage and ac frequency and the design of the controller is only based on input/output (I/O) measurement data but not the model any more. Second, we investigate the same problem for more than two microgrids connected by ICs. An event-based distributed consensus control approach is proposed to address this issue. We first construct the agent system for each IC and design its consensus control protocol, which uses a cooperative approach to indirectly adjust the active power load of individual microgrid. Then, an event-based control scheme is utilized to design the consensus protocol to reduce the communication between interlinking converters. The proposed distributed control method allows a sparse communication structure and higher reliability and flexibility operation. Simulation results are presented to demonstrate the proposed control method.