Stabilization of DC Nanogrids Based on Non-Integer General Type-II Fuzzy System

Abstract

This brief proposes a dynamic consensus algorithm-based nonlinear I-V droop control for the balancing state of charge of energy storage systems (ESSs) in DC Nanogrids (DCNGs). The dynamic consensus algorithm (DCA) provides a coordinated secondary control with sharing information between Distributed Generation (DG) units to regulate the output power of each DG based on the capacity and state of charge (SoC) of the ESSs. Furthermore, a novel high bandwidth fractional order general type-2 fuzzy logic proportional-integral-derivative (FOGT2FPID) controller is applied in the secondary control level to ensure fast and accurate voltage regulation, and SoC balancing in the DCNG. In the primary control level, a nonlinear I-V droop control approach provides fast dynamic and accurate power-sharing among DGs. Moreover, the proposed control method can provide reliability, modularity, and flexibility. Compared with conventional methods, over-current failures and abruptly disconnection of DGs are prevented with the proposed controller. Experimental results are shown to verify the effectiveness of the proposed control scheme under different scenarios using facilities at the Microgrid Laboratory, Aalborg University.