| With the increasing environmental pollution, people started to use a new clean green energy instead of highly polluting fossil fuels. Solar energy as a clean green renewable energy, its advantage is inexhaustible, pollution-free, no noise, and its application has become a hot area of new energy sources. PV power generation is an effective way to make full use of of solar energy. Due to the current price of PV panels is relatively high, the conversion efficiency is relatively low, in order to reduce system cost and effective use of solar energy that PV maximum power tracking is particularly necessary.As the core component of PV power generation system, the size of the output power of PV cells represent the strengths and weaknesses of photovoltaic power generation system performance. But when affected by external conditions, photovoltaic cells has remained in the maximum power output power is not the condition, therefore, an make use of MPPT control technology of real-time adjustment of photovoltaic cells working point, the maximum power point of PV cells have been working in, to maximize the utilization of PV cells.This article is the use of stand-alone photovoltaic power generation system photovoltaic cell power generation system and the principle of theoretical analysis, at the same time the basic algorithm forconducted in-depth research, and ultimately come up with a new MPPT algorithm, and its the simulation analysis. Specific work contents are as follows:(1)Introducing the factors affecting affect the PV cell power conversion efficiency and analysis the equivalent circuit of the PV cell. Establishment the mathematical and simulation of PV cell to verify the nonlinear. And test the output characteristics of PV cell under different environmental condition, to carries on the corresponding analysis.(2)Due to PV cell parameters don’t match, the Photovoltaic array may be power loss. On the basis of theoretical analysis, this paper builds two monomer’s simulation model and draw the results to given the relevant principles of choice parameters. Analysis hot spot effect of array, it can be seen that partially shading play an important role on the hot spot effect. Taking the project with mathematical model as the foundation, it gived mathematical and simulation model of the condition of shadow and get I-U and P-U characteristic of PV cell. Study on partially shading output characteristic factors, such as array pattern, keep out mode, shadow quantity, illumination and temperature, to get corresponding conclusion, and given the position detection methods of partially shading.(3) Analysis of working principle of the MPPT, its corresponding classification is given. Working principle of several kinds of common control methods were analyzed, and gives the advantages and disadvantages between them, in several common control algorithm based on an improved control algorithm, improve the MPPT tracking control accuracy and speed, to avoid the maximum power point of "misjudgment". Build for photovoltaic power Boost DC/DC converter.(4) Established the simulation model with the function of MPPT photovoltaic power generation system. In the same simulation conditions, first of all to CVT,P&O,InCond,FLC four methods are simulated, finally to improve the MPPT control algorithm in the simulation analysis, by observing the corresponding simulation waveform output power, and comparison, it is concluded that the effectiveness of the improved algorithm. |
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