Analysis and Modeling of Photovoltaic Module Degrading Process

摘要

With the increase of the using time, the photovoltaic array will degrade and the output power will decrease. This paper proposes a mathematical model of the photovoltaic module degrading process. The degrading model bases on Latin hypercube sampling in the Monte Carlo simulation, using photovoltaic cells I-V characteristic function, environmental conditions and internal parameters, through normal and log-normal distribution fitting transmittance of photovoltaic modules, change in series resistance and parallel resistance. Through the proposed photovoltaic modules degrading model, a large amount of simulation results shows that, with the modules degrading, the photovoltaic modules maximum power point will deviate and diverge. The major cause of output power decrease is short circuit current attenuation. The aging of parasitic resistances mainly influences short-circuit current and open-circuit voltage, and fill factor has little change with the degrading of system. These characteristics lay a foundation for intelligent diagnosis of photovoltaic module degrading.