An Adaptive Fuzzy Controller-Based Distributed Voltage Control Strategy for a Remote Microgrid System With Solar Energy and Battery Support

This paper presents a robust decentralized voltage control strategy for a remote microgrid (rMG) system. The proposed decentralized voltage control strategy is applied to a voltage source inverter (VSI) through a pulse width modulation (PWM) technique. To implement the strategy, a small-scale remote microgrid test system is considered, supported by solar photovoltaic (SPV) and battery energy storage system (BSS). The two sources are connected through a common inverter connected to a three-phase system. Maximum power extraction is considered from the SPV system using an MPPT-based algorithm. The output voltage of the common inverter is maintained by triggering the inverter circuit in a controlled way using the PWM technique. BSS charging and discharging are also controlled through a controller circuit. The uncertainty in the solar irradiance data is captured through a series of variations with different slew rates. The output voltage VSI is controlled using an adaptive fuzzy PID controller (AFPID). This controller eliminates the need for the optimal adaptation gain value for robust control. The VSI voltage control is achieved by considering the peak value of the three-phase AC voltage as a reference, and a closed-loop dq control is implemented. The results are analyzed under various system conditions, and a comparative assessment is obtained with other control schemes such as dual-loop PID, model reference adaptive controller (MRAC), and APID controller. It is observed that the AFPID provides better voltage control and stability to the system as compared to other control schemes. The overall performance of the proposed fuzzy controller is investigated with the help of various performance indices.