Coordinated Power Management of the Subgrids in a Hybrid AC-DC Microgrid with Multiple Renewable Sources

This paper presents the assessment of the operation and control of hybrid AC-DC microgrid (HMG) integrated with alternative energy sources. The system is analyzed by incorporating fuzzy logic and adaptive neuro-fuzzy inference system (ANFIS) based controllers in the control scheme of battery. Photovoltaic array and fuel cell system are coupled to the DC bus and an electrolyzer based hydrogen storage system is used for energy storage in the DC subgrid. The output of the wind energy system along with the battery is fed to the AC bus through an inverter. The AC and DC subgrids are integrated through an interlinking converter which is controlled to facilitate power exchange between the subgrids based on the frequency of AC bus and DC bus voltage. Appropriate power management is achieved within the subgrids and between the subgrids by the coordinated control schemes employed in the HMG. The main focus of this article is the analysis of the impact of incorporating conventional proportional-integral controller, fuzzy logic controller and ANFIS based controller in the control scheme of the battery when the subgrids are subjected to power fluctuations. By employing the ANFIS based controller, the transients in the voltage and power output of the battery system are minimized and deviations occurring in the AC bus voltage during load variations are reduced.