Research Of Photovoltaic Power System Based On The Bifurcation Theory

Faced of the increasing serious traditional energy crisis and the environment pollution,solar power plays a dominant role in the new energy technologies, With the scale of photovoltaic is continuing to expand and the grid-connected voltage and capacity is getting higher and higher, photovoltaic power system technology has been more attention and concern. The stable operation of photovoltaic power system is an important content in the photovoltaic power system. However, bifurcation phenomena as an important non-linear phenomenon in the power system, it can affect the stability of system operation. Therefore,the bifurcation theory is very necessary to study the bifurcation phenomena in photovoltaic power system. The paper’s main research and conclusions are as follows:Firstly, this paper researches the bifurcation phenomena in DC-DC boost converter of photovoltaic power system, introduces the basic structure of photovoltaic power system, and uses mathematical model of photovoltaic cells to simulate output characteristics. The discrete model of DC-DC boost converter has been established. Research the bifurcation phenomena when reference current and input voltage change respectively. Then, the simulation model of the DC-DC boost converter as input of photovoltaic cell have been set up to study how the illumination intensity influence bifurcation phenomena in DC-DC boost converter.Secondly, this paper researches the bifurcation research and its control method in inverter of photovoltaic power system. The discrete model has been established and bifurcation has been analyzed based on numerical method of bifurcation theory and computer simulation. Washout-filter Feedback Control method is used to control bifurcation phenomena in inverter. The new bifurcation point has been calculated through using the discretization model programming simulation by adding the control. At last, the simulation model of photovoltaic inverter has been set up and simulation result shows that the stability of the system has been improved through Washout-filter Feedback Control method.