The Efficiency Of Photovoltaic Power Generation System Optimization

As the energy depletion and environment pollution becoming more and more serious in the world, photovoltaic has come to be one of the most practical and cleanest power generation methods, which has a large-scale development prospect. However, as the output characteristic of photovoltaic cells is non-linear, and be easily influenced by the outer environment, how to make the use of solar energy more effective has become a difficult problem in this area. This paper tries to study photovoltaic system with the target of maximizing the efficiency of solar energy, and both the theoretical and experimental research of photovoltaic system efficiency optimization has been done. Specifically, the main content of this article can be summarized as follows:First, this paper generally introduces the constitution and classification of photovoltaic system, according to different occasion. In addition, the application of photovoltaic in china is introduced. On the basis of that, the principle of solar panels is discussed with details. We can get output characteristic curve of solar panels which can show that: solar cells are neither constant voltage source nor constant current source, it can not provide arbitrary large power for the load; and the characteristic of solar cells is non-linear, which can be influenced by the environment factors such as solar radiation.Second, on the basis of 110W_p solar cells in the laboratory, solar cell are tested in the same light and in different lights to get experimental curves which not only show that the characteristic of solar cells is non-linear, but also have great practical value for the simulation.Third, by comparing several traditional optimization methods of photovoltaic system efficiency, we get the following conclusions. The implementation of CVT(Constant Voltage Tracking)is relatively simple, stable, but the accuracy of control is poor; the output voltage of ICA(Incremental Conductance Algorithm)can be relatively stable, however, the whole system is more complicated, and the cost is high; The implementation of Power Feedback Method is convenient, but because the stability and reliability is not satisfactory, it's not commonly used in practice; The control of PAO(Perturb-and-observe) is easy, but there may be oscillation and misjudgment. In the basis of 110W_p solar cell, we use PAO in the photovoltaic system, the simulation results show that there will be a power loss in the vicinity of the maximum power point.Last, I try to apply the Genetic Algorithms in photovoltaic system. Genetic algorithms consider the problem as "chromosome", place the issue in the "environment", and choose the "chromosome" to copy, according to the principle of survival of the fittest. A new "chromosome" group can be produced through the crossover and mutation of two genes. Finally, it can converge to the individual which is most suitable to the environment. At first, it retains the best chromosome, and if founds a better chromosome in the new species, it will use it to replace the original chromosome so that the last chromosome can be seen as the most optimal results. The use of Genetic Algorithms in photovoltaic system improves the efficiency of solar energy use. Simulation results and experimental results, show that the method is feasible.