Battery and supercapacitor assisted controller for stability enhancement of DC microgrid

Abstract

AbstractDespite the widespread popularity of DC microgrid (DCMG), one of the key issues faced by it is the instability arising from supply‐demand imbalance, which is conventionally tackled via energy storage units such as batteries. But the life cycle of the battery, which may reduce when subjected to transients, can be prolonged by integrating fast acting supercapacitor (SC) with higher power density. Such a combination of energy storage units enables the DCMG to handle steady state and transient conditions effectively. However, the reduction in the operating voltage of SC may bring in ringing in the DC bus voltage, which will affect DCMG stability. Hence, this paper focuses on analysing the impact of SC voltage deviation on DCMG stability and to propose a controller design procedure with conventional PI controller and power management strategy to mitigate the aforementioned consequences. The simulation in MATLAB and real‐time validation in OP4510 real‐time simulator has been conducted. The results of both revealed that the proposed scheme has succeeded in eliminating ringing of DC bus voltage, irrespective of the SC operating voltage variations, thereby maintaining DCMG stability.