A New Method for Global Maximum Power Point Tracking of Photovoltaic Arrays Including Several Parallel Strings under Partial Shading Conditions

In this paper, a new method for extracting the global maximum power point (GMPP) of a PV array under partial shading conditions (PSCs) is presented. In the proposed method, it is shown that, independent of the pattern and intensity of the radiation, the GMPP position is always in the neighboring of the global peaks of one of the photovoltaic (PV) strings in the PV array. Therefore, in contrast to the existing methods in which the number of local peaks, tested as a GMPP candidate, is dependent on the number of different radiation levels on the array surface, in the proposed technique this number is reduced to the number of parallel strings in the photovoltaic array and is independent of the irradiation pattern on the PV array. As a result, to track the GMPP in PSC, first the GMPP of each PV string is estimated, and then the voltage of each of the estimated points is given to the power electronic converter as a reference voltage to regulate the PV array voltage at the corresponding candidate GMPP voltage. Next, in each case, the produced power is recorded and the voltage that produces the maximum power is known as the final GMPP of the PV array. Numerical results and comparative study with similar methods confirm the desirable performance of the proposed algorithm in finding the GMPP with an acceptable speed and accuracy.