Adaptive voltage regulation of islanding DC microgrid with multiple distributed PVs and storage units

Abstract

The DC microgrids embedded with a collection of dispersed small-scale distributed renewables and storage devices have become prevalent for power supply as a complimentary component of power utilities. In islanding DC microgrids, the energy storage system (ESS) is indispensable to maintain the power balance and voltage stability considering the dynamic loads and intermittent nature of distributed generations (DGs). Also, the reasonable current sharing amongst the connected energy storage units (ESUs) is needed to prevent individual storages from deep discharge or over-charge. Most existing solutions are based on droop control and attempt to obtain the trade-off between bus voltage regulation and current sharing performance, but with the limitation that the best trade-off can be hardly obtained or the deviation from the desired bus voltage always exists. In this paper, we present a decentralized DC bus voltage adaptive regulation approach for islanding microgrid which incorporates the State of Charge (SoC) information into the double closed-loop control for DC/DC converters of ESUs. The proposed adaptive control solution is verified and assessed through a set of simulation experiments for a range of operational scenarios for the DC microgrid with multiple distributed batteries and PV generators. The numerical result clearly indicates that the DC bus voltage can be excellently managed simultaneously the utilization balance of multiple ESUs can be obtained without communication.