The Modeling Of Photovoltaic Array And Equalization For Partially Shaded Conditions

With the storage of fossil energy rapidly decreasing and environment pollution becoming worse and worse, photovoltaic (PV) technology has been valued as the most important method on making use of solar energy without any pollution. Research on PV technology has been developed a lot so that solar energy could be the main energy which would be used to generate electric power as soon as possible. This paper focuses on the modeling of PV array and improving its generating efficiency. Although PV array has been modeled by one equation, it suits for research that does not focus on the generating power part of the system. It is necessary to study the model of PV module to improve the efficiency of array with researching its output characteristics. Therefore, a mathematic model of PV module which is suitable for simulation is chosen, and three kinds of simulation software are used to achieve the simulation purpose.Partially shaded conditions are not able to avoided, which would cause the decreasing of produced power and efficiency of PV array. Maximum power point tracking for partially shaded conditions is widely used to reduce the power loss, and a MPPT method is introduced in the paper because of its high feasibility. MPPT methods for partially shaded conditions are good for power collecting, but it is still complex. Power produced by partially shaded PV modules is wasted by the function of by-pass diodes, which exactly causes power loss of PV array. Consequently, equalization for partially shaded PV modules is proposed by researchers. This paper chooses a simple equalization method which uses a multi-stacked SEPIC as the voltage equalizer. The operation and control strategy of the equalizer are analyzed in this paper, and simulation and experiments can verify its feasibility.