| As the traditional fossil energy reducing and the environmental pollution increasing, solar energy gradually become a new type of energy drawn attention to research because of its advantages of sustainability, cleanness, universality, etc. In order to make use of solar power generation with higher efficiency, scientists systematically research the photovoltaic power generation system, and the PV maximum power point tracking(MPPT) is a hotpot of current research. This paper studies the maximum output power of photovoltaic array under the condition of partially shaded.First, an introduction about the research background, the research status of photovoltaic power generation and photovoltaic system MPPT technology are given. Second, independent photovoltaic power generation system is analyzed. In this part, the solar cell power generation principle, the mathematical model of solar cell power generation, the solution to hot spot effect in shading conditions and the simulation of the solar cell in partial shading conditions are elaborated. The control principle of the solar cell maximum power point tracking and several traditional control algorithms are then introduced, and a conclusion that traditional control algorithms can not find the maximum power point in partial shading conditions is obtained. In order to track the maximum power point under partial shading conditions, this paper uses an improved particle swarm optimization algorithm named fallback particle swarm algorithm. The algorithm is better than standard PSO algorithm in term of accuracy and convergence speed which are verified by testing benchmark function. Finally, the simulation model is built in Matlab, in which fallback particle swarm algorithm is applied to find out the maximum power point. The results show that the algorithm tracking speed faster, control precision higher, output power more stable, this is a high quality control algorithm to improve the efficiency of independent photovoltaic system output. |
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