An enhanced MPPT technique for high gain DC-DC converter for photovoltaic applications

This paper presents an improved Maximum Power Point Tracking(MPPT)of Photovoltaic (PV) systems for switched coupled inductor step up DC-DC converter. PV array can feed power to the load through DC-DC converter boosting the output voltage. Due to the stochastic behaviour of solar energy, MPPT control technique of PV arrays is required to operate at maximum power point. The main contribution of this paper is enhancement of Perturb and Observe (P&O) method and fuzzy controller for varying solar radiation. The characteristics corresponding to output power, output voltage and efficiency for P&O and fuzzy controller are obtained and their performance is compared. The comparison of gain values for conventional boost converter, high step up non isolated DC-DC converter and positive output superlift Luo converter has also been done in this work. The advantages of high voltage gain of switched coupled inductor converter has been integrated with the search for maximum power point. The closed loop control using PI controller facilitates the provision of maximum power to the system at all varying insolations. The closed loop PI controller with P&O tracking for PV system results inconstant output voltage of 396V for varying insolation.