An Adaptive Fractional Order MPPT Control for Maximum Power Extraction From Solar Photovoltaic System

Traditional MPPT techniques have inherent limitations such as slow convergence, incompetent toward rapid and extreme atmospheric conditions, and oscillations at maximum power peak (MPP). This paper presents a novel adaptive maximum power point tracking controller to mitigate the drawbacks of traditional MPPT techniques. In the devised control strategy, proportional and integral controller gains are made adaptive with respect to instantaneous error, which in turn reduces the power losses. Further, non-integer integral and derivative coefficients of PID controller have been employed to enhance the accuracy. Here, Lambert-W function is used to convert implicit equation of solar PV model into explicit equation to calculate the output power and its derivative. Parameters of the proposed controller are optimized using dragonfly optimization algorithm. The proposed scheme is analyzed on a string of KC130GT solar module consisting of a 4S1P configuration. The performance of the proposed controller is examined in terms of convergence rate and power tracking competency under six different irradiance profiles, that is, (i) constant irradiance, (ii) slow varying irradiance, (iii) fast varying irradiance, (iv) sinusoidal irradiance (v) extreme varying irradiance, and (vi) partial shading condition. Moreover, the performance of the proposed controller is investigated over other state-of-art MPPT controllers based on efficiency analysis, RMSE value, and time response analysis. The result reveals that the proposed technique offers the highest tracking efficiency of 99.38% under constant irradiance, whereas PID and AN-PID recode the average efficiency of 99.05% and 98.79%, respectively. It can be noted that ANFOPID recorded the highest tracking efficiencies for other irradiance patterns in comparison with other designed controllers. Moreover, AN-FOPID consistently exhibits the lowest RMSE values and efficient time response performance, indicating its superior performance compared to the PID and AN-PID techniques.