Simulation and Analysis of Current Ripple in an Experimental DC Nanogrid
Abstract
The global challenges of climate change and growing energy demand have accelerated the adoption of renewable energy systems, particularly for remote communities lacking access to conventional power grids. Direct Current Distribution Nanogrids (DCDNs) offer an efficient solution for integrating renewables, but they can face power quality challenges due to the inverters required for AC loads. This study presents an analysis of current ripple phenomena within a DCDN, modeled in MATLAB/SIMULINK and based on an experimental system designed to supply power to remote communities in the Amazon. The system comprises three distributed photovoltaic generators with integrated storage units, supplying power to three distinct load banks, one of which includes an inverter for AC appliances. Through five simulations with progressively increasing power demands on the AC load, the propagation and impact of ripple were investigated throughout the grid. The inverter is the primary source of ripple, introducing significant harmonic distortions with a fundamental frequency of 120 Hz on the DC side. A correlation was established between higher ripple magnitudes, increased circulation of non-active power, and consequently, greater power losses in the distribution grid. The ripple factor (RF) was used as a metric for quantifying these disturbances and their impact on system efficiency. These findings are important for designing robust off-grid DC power systems, highlighting the need to mitigate ripple effects to ensure power quality and reliability.
Keywords
nanogrid, direct current, electronic device modeling, simulation, communities