Fuzzy-PI Controllers for Voltage and Frequency Regulation of a PV-FC Based Autonomous Microgrid

This paper presents a study on PV and fuel cell (FC) based DC microgrid (MG). The PV array and FC stack act as energy sources and a hydrogen electrolyzer system is used for energy storage whenever surplus power is generated by the PV source. A supercapacitor (SC) bank is utilized for short-term energy storage to handle abrupt changes in load demand. This system is capable of supplying both DC and AC loads. The inverter is controlled by a voltage and frequency (V&F) control scheme to regulate the deviations in frequency and voltage. PI controllers and fuzzy logic based self-tuning PI controllers (Fuzzy-PI) are used in the inverter control scheme to regulate V&F deviations caused due to the changing AC loads and their effects on the system are analyzed and compared. With fuzzy logic based self-tuning PI controllers, the frequency and load current deviations are found to be minimized. Modelling and simulations are accomplished in MATLAB/Simulink software.