Simulation Of The Stand-alone Photovoltaic System Based On The Dichotomy And Variable Step Size Algorithm

With the development of technology and global economy, the energy consumption maintains rapid growth. Meanwhile, the pollution resulted from energy consumption makes great challenges to the living environment of human being. Therefore, as the main clean energy, solar energy is getting more and more attention. The transfer efficiency of solar panel is low and its output characteristics heavily depend on the external environment, so it is important to investigate the maximum power point tracking technique to increase the transfer efficiency of solar panel.In this paper, the principle of solar panel, maximum power point tracking, DC/DC converting circuit and the property of battery are investigated. The dichotomy and variable step size algorithm is proposed. This algorithm can detect the maximum power point with speed and accuracy, but only brings a small vibration after obtaining the maximum power point, which improve the stability of the system.In this paper, the solar cell is modeled and simulated by Matlab/Simulink, and the effects of the inside and external factors to the output character of the solar cell is analyzed. The dichotomy and variable step size algorithm is simulated by connecting the solar panel model and the converting circuit. Compared to the Perturb and Observe algorithm, the results indicate that this algorithm can effectively track the maximum power point. In additional, new maximum power point can be easily got when the external circumstance changes. The feasibility of interim charge by varying current is studied by editing M function and establishing converting circuit model. Finally, the design of system circuit is completed. The output voltage and current of solar cell and the voltage of storage battery are collected and analyzed by PIC microcontroller.