Research Of Chaos Phenomenon In Photovoltaic System

The human social life and cultural life is in the premise of energy, besides the level of human life depends greatly on energy utilization. It is inevitable that the fossil energy may dry, so the renewable energy development and utilization is pressing. Considering environment factors and development potential in the process of using energy, photovoltaic power generation technology has been more attention and concern. However, stability of photovoltaic power generation system operation is a key factor, the bifurcation and chaos phenomenon is included in the system stability analysis. At present, there is less literature that studied chaos phenomenon in the system. The paper analyzed the segment that may cause chaos phenomenon in the photovoltaic system on the base of photovoltaic system model. The paper’s main research and conclusions are as follows:(1) For voltage-mode control Buck converter, Buck converter simulation model using Laplace transform method is constructed based on Matlab/Simulink. According to choosing different parameters, the nonlinear phenomenon in Buck converter could be analyzed comparing time domain with V-I phase space. Based on Matlab/Simulink simulation, when parameters of the system meet certain conditions, the system will appear chaos phenomenon, we can observe the process from the stability to the chaos in the Ⅴ-Ⅰ phase diagram.(2) This paper puts discrete system discretization thought apply to analyze single-phase bridge inverter circuit in photovoltaic power generation system, what is more, established the mathematical model of the single-phase bridge inverter circuit. The chaos theory was applied to analyze nonlinear phenomena in the single-phase bridge inverter circuit, through making compare the bifurcation diagram with the lyapunov exponent picture, this paper revealed the period-doubling bifurcation to the border collision bifurcation and chaos in the single-phase bridge inverter circuit. Simulation results showed that:when the control parameters are in a very small range change, single-phase bridge inverter circuit appears some nonlinear phenomenon in the process of the circuit topology changes.The paper made the conclusion that when the system parameters can meet certain conditions, photovoltaic system DC-DC chopper converter and inverter can happen a series of nonlinear phenomenon such as bifurcation and chaos.