Design of interval type-2 fuzzy logic controller based maximumpower point tracking for a photovoltaic system

Photovoltaic systems have advantages such as environmental friendliness, noiseless operation and no fuel costs, as well as disadvantages such as high investment costs and low efficiency in energy conversion. For this reason, studies to increase the efficiency of photovoltaic systems have gained importance. In order to operate a photovoltaic system at maximum efficiency, a maximum power point tracking (MPPT) method must be used. With the MPPT method, photovoltaic panels can always be operated at the maximum power point and more efficiently. In this thesis, a robust Intermittent Type-2 Fuzzy Logic (IT2BM) based method is proposed for MPPT control of a DC-DC converter fed from a photovoltaic panel. With the proposed method, it is aimed to reduce the oscillations in power and to have the least effect on the performance of the MPPT method in changes in load and weather conditions. In order to evaluate the performance of the proposed method, a Matlab/Simulink simulation model including 4 1Soltech 1STH-215-P brand 213.15 W photovoltaic panels, amplifier type DC-DC converter, load and MPPT method was created. The switching frequency for the converter was selected as 5 kHz and the gate pulses were generated by the pulse width modulation (PWM) method. The designed IT2BM has two inputs and one output. Inputs to IT2BM are determined as error (E) and change of error (!E), and output as duty ratio (d). The dynamic performance of the simulation model was investigated by keeping the panel temperature constant and changing the radiation according to time. The simulation results including the load current, load voltage, panel current, panel voltage, panel power and efficiency of the MPPT method obtained from the proposed MPPT method under these operating conditions are given. In addition, the simulation results were compared with the results of the P&Q MPPT method for the same operating conditions to show the effectiveness of the proposed MPPT method. The results show that the IT2BM-based MPPT method has a superior performance than the P&Q MPPT method in terms of response speed and power oscillation. Keywords: Photovoltaic Systems, Maximum Power Point Tracking, MPPT Methods, Perturb - Observe, Interval Type-2 Fuzzy Logic Controller