Design and Implementation of Power Management System in Multi-String Solar-Interfaced DC Microgrid With Energy Storage System

The DC microgrid (DCMG) offers a promising approach to efficiently distribute and manage renewable energy sources (RES), enhancing energy resilience and reducing reliance on traditional fossil fuel-based power generation. The intermittent nature of RES in DCMG can cause voltage and power fluctuations, potentially impacting the microgrid’s reliability, power quality, and stability. To bridge the gap between intermittent RES power generation and consistent load demand, energy storage devices (ESD) are necessary. Excessive charging and discharging cycles can degrade the performance of ESD. Hence, in this article, a condition-based power management algorithm (PMA) is proposed for a multi-string solar interfaced DCMG with electric vehicle (EV) batteries and the grid for powering residential loads. The primary aim of the PMA is to maintain stable DC bus voltage irrespective of variations in irradiance and load, to promote effective power sharing between the available resources, and to mitigate the risks of excessive charging and discharging of ESD. The performance and efficacy of the PMA are validated in a hardware setup using a low-cost FPGA-based controller. Different modes of operation are considered in this study to analyze the performance of the PMA, and their experimental results are presented.