Closed-Loop Design of Fuzzy Logic Controller in Solar Power Generation

This paper presents the designing of the MATLAB model for a closed-loop fuzzy logic controller in solar power generation. To reduce harmonics generated by non-linear loads, a reference signal of the load is given to a fuzzy controller in order to make the system as a closed loop. The main objective of the proposed method is to improve the efficiency of the system by reducing Total Harmonic Distortion (THD) in the source current. When Photo-Voltaic (PV) module produces more amount of power, the battery is charged through the bi-directional converter. The load is supplied by the battery when solar irradiation is less. Complete discharge of the battery is prevented by using the State of Charge (SOC) control on the battery. To obtain an extent power from the PV unit, the battery charging circuit is attached closer to the source instead of connecting before load, it minimizes the stages of power conversion. By using fuzzy-based PWM method power is controlled through a DC-DC converter. AC load is powered by using DC-AC inverter. Also, to control the bi-directional DC-DC converter PID controller is utilized along with switches. The parameters we have taken for obtaining THD are, the number of cycles is 1 at starting time 0.15 sec and the fundamental frequency is 60 Hz, for these values THD comes 1.47%. The result reveals that in closed-loop fuzzy logic controller total harmonic distortion is less than 5%.