Impact of Control Systems on Power Quality at Common DC Bus in DC Grid

摘要

DC microgrid is becoming very popular because of its easy and cost-effective interface with renewable resources and extensive use of power electronics (PE) loads in daily life. Nevertheless, this emerging technology poses significant challenges in terms of energy management, stability, and power quality. Power quality deteriorates mainly in the grid due to the presence of harmonics condition. Due to the harmonics yielding from power electronic devices, maintaining power quality in DC grids is a challenging task. A similar issue is well investigated in the AC power system but is yet to be fully investigated in DC grid. To this end, this paper investigates the impact of control systems on the power quality in the common DC bus of a DC grid. To do so, first, a small-scale DC microgrid is considered and three methodologies including impedance scanning, fast Fourier transform (FFT) analysis, and time domain simulation are applied. Second, the impact of disturbances on power quality in DC Bus is explored. Finally, a mitigation technique based on the LQR approach is proposed. Through case studies, it is shown that the outcome of this research can potentially be used for modeling LVDC grid, reduction in energy consumption and CO2 emissions.