Research On Maximum Power Tracking Method Of Photovoltaic Power Generation System

In the new energy, solar energy is a kind of green energy which is clean, non-polluting, inexhaustible.Currently the development of solar photovoltaic technology makes photovoltaic cells in the energy sector has been more widely used and attention. As the photoelectric conversion efficiency of photovoltaic cells is currently only maintained at between 10%-20%, which is an important factor limiting its development. Therefore, to improve the conversion efficiency of photovoltaic cells is the main direction of research in this area. The photovoltaic power generation system maximum power point tracking algorithm is regarded as the direction and content in this paper, then carried out the following studies:First probes the background and significance of the field of photovoltaic power generation, analyzes current situation at home and abroad, masters the importance of research in this field. Introduces several common MPPT algorithm, and analyzes their advantages and disadvantages. Then introduces the basic components of a photovoltaic power generation system, including photovoltaic cells, batteries, charge controllers, DC/DC, DC/AC converters and other components. And analyzes the generic model and a simplified model of photovoltaic cells, then use Matlab/Simulink built a simplified model of photovoltaic cells. Analyzes the output characteristics of the photovoltaic cell through the output power voltage and current characteristic curve with the model. Study and master the output characteristic curve is a difference when photovoltaic cells at different temperatures and under different light conditions, and also verify that it is important to take maximum power tracking method in the photovoltaic power generation system. Introduces several conversion circuits which can be used in the photovoltaic power generation system. By comparing the advantages and disadvantages between them, select Boost circuit as the control circuit to verify the validity of the algorithm. Then using Matlab/Simulink software to build simulation models of traditional disturbance observation method to simulate. To know the traditional disturbance observation method exists tracking slowly and concussion problems.To solve the problems in the conventional disturbance observer method, proposes an improved variable step disturbance observation method. Finally using Matlab/Simulink software to establish a simulation model of improved disturbance observer method which is based on Boost circuit, and verify the rationality and feasibility of the improved algorithm when selecting step size. Final conclusion:the modified disturbance observer method can improve the maximum power point tracking speed of photovoltaic power generation system, and improve stability of system when the system is stationary steady-state operation.