A two-step global maximum power point (GMPP) tracking algorithm for photovoltaic (PV) system powered by a string of series-connected solar panels will be presented. In the first step, the power-voltage characteristics...
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ISBN:
(纸本)9781479923250
A two-step global maximum power point (GMPP) tracking algorithm for photovoltaic (PV) system powered by a string of series-connected solar panels will be presented. In the first step, the power-voltage characteristics of the string is extracted by changing the input impedance of the inverter through three phases, so as to determine the number of panels in operation at the approximated GMPP. In the second step, the exact location of the GMPP is determined by formulating two second-order power functions, namely actual string power function and fictitious power function, and finding the intersection point of the two functions. The proposed algorithm has been evaluated on a 3kW grid-tie PV system with a PV simulator connected. The two different power-voltage characteristics are programmed and switched in order to test and compare the tracking performances of traditional perturband- observe (P&O) and proposed mpptalgorithms. Results show that the proposed algorithm takes 2.5 seconds for the step-1 process and 1 second for the step-two process to locate the GMPP. Without the first step, the speed of the second step is three times faster than the P& O algorithm.
A new hybrid global maximum power point (MPP) tracking (mppt) method is introduced in this study by using an improved 0.8V(OC) model-based algorithm containing a smart power scanning procedure which is based on the si...
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A new hybrid global maximum power point (MPP) tracking (mppt) method is introduced in this study by using an improved 0.8V(OC) model-based algorithm containing a smart power scanning procedure which is based on the sign of a change of photovoltaic (PV) module power. By courtesy of this procedure, the global MPP is determined effectively and within a small scanning time interval. The effectiveness of the proposed global mppt algorithm has been validated by experimental studies. One of the buck-boost converter types, a single-ended primary inductance converter was implemented in this context. Experimental results show that tracking efficiency in the proposed algorithm is very satisfactory since blind scanning is prevented. Furthermore, it is presented in the experimental results that tracking efficiency is bigger in the proposed shading detection approach by up to 11.29% than the other technique which monitors voltage and current variations. In addition, there are no high software and hardware burdens which make this mpptalgorithm applicable especially in the smart alternating current module, module-integrated converters, PV power optimisers, and module level distributed mppt applications.
Photovoltaic array output characteristics under partial shading conditions have multi local maximum power points, but traditional maximum power point tracking methods failed to identify global maximum power point. Out...
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ISBN:
(纸本)9783037856703
Photovoltaic array output characteristics under partial shading conditions have multi local maximum power points, but traditional maximum power point tracking methods failed to identify global maximum power point. Output characteristics of shadowed PV array under different illumination were simulated by Matlab software. The rule between voltage of possible local maximum power point and the open circuit voltage was summarized. According to this rule, a modified algorithm based on the Incremental Conductance method was put forward. Simulations results indicated that the proposed mpptalgorithm can accurately track the global maximum power point under uniform illumination and partial shading conditions. It can improve the efficiency of PV system.
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