Stability Enhancement of DC Microgrid Operation Involving Hybrid Energy Storage and Pulsed Loads
Ahmed Aghmadi, Ola Ali, Osama A. Mohammed
Abstract
DC standalone microgrids are emerging as an effective solution for integrating renewable energy sources (RESs) and accommodating the widespread use of DC loads and energy storage systems (ESSs). However, the intermittent nature of RESs and the challenges posed by load requirements, such as pulsed power loads (PPLs), threaten MG stability and resiliency. To address these challenges, this paper introduces a Hybrid Energy Storage System (HESS) control framework, integrating a battery energy storage system (BESS) and an Ultracapacitor (UC) designed to tackle high and low-frequency components in power demand for enhancing MG stability in diverse practical operational conditions. Key innovations include the first-time experimental validation of the HESS control scheme under variable PPL. A novel Linear Active Disturbance Rejection Control (LADRC)-based voltage control scheme will be introduced. Simulation and experimental validation are conducted to test the proposed control scheme, showcasing superior performance in DC bus voltage regulation compared to traditional BESS-only systems under constant PPL. Moreover, under the most severe loading condition, the variable PPL, the proposed LADRC-based HESS control has demonstrated robust and resilient performance, outperforming both PI-based HESS control and BESS-only. This study advances resilient and reliable power systems by addressing the intricate challenges posed by constant and variable PPL in DC standalone microgrids, paving the way for sustainable energy solutions.