Comparative Studies of DC-DC Boost Convertor and SEPIC Convertor for Global Maximum Power Point Tracking Technique in a PV Array under Partial Shaded Condition

This thesis portray a validation and design of a Maximum Power Point tracking (MPPT) capable of tracking the true global Maximum Power point (GMPP) in the present of other local maxima. The proposed system tracks Maximum Power point (MPP) without the use of costly components such as single concreters and microprocessors thereby the compactness of the system. In this paper we are using DC-DC Boost convertor and SEPIC Convertor and perform comparison between both. This paper also discusses about an improved technique for tracking global maximum power point of photovoltaic arrays that has better performance under partial shading conditions. The first stage in this method is to find out global maximum power point among the local maxima. Once the global maximum power point is found then by adjusting the duty ratio, the voltage corresponding to maximum power can be found out. The control is then transferred to perturb and observe algorithm stage. This technique could be applied for both stand alone and grid connected PV system. A comparison study between a SEPIC converter and a buck boost converter with the above mentioned algorithm has also been carried out in order to verify the performance of both the converters. Modified algorithm has been simulated using MATLAB/Simulink and results are obtained. Partial shading condition was modelled in MATLAB/Simscape and analyzed the solar array characteristics under various shading conditions. From the simulation results it was found that the SEPIC converter is much more efficient and is highly suitable for photo voltaic applications