Degradation Model of Photovoltaic Modules under Multi-Environment Factors Coupling Based on FEM and Failure Physical Model

Degradation of photovoltaic (PV) module is effected by environment factors such as ambient temperature, ambient humidity, solar irradiation, wind speed and complicated coupling effects. Therefore, the performance degradation is difficult to be accurately assessed, especially for the output power of PV modules. Based on Finite Element Method (FEM) and failure physical model, a degradation model of output power is proposed, where environment factors and coupling effects are considered. First, based on monitoring environment data, the physical field of the PV module is simulated using FEM. Then, module temperature and module humidity are obtained based on the results of physical field simulation. Putting module temperature and module humidity into the failure physical model, the performance degradation rate is obtained. Finally, a degradation model of output power is obtained by combining the output power and degradation rate. The effect of diffusion coefficient on output power degradation is analyzed by varying the diffusion coefficient. Results show that effects of ambient temperature on module temperature and diffusion process cannot be ignored, and the effect of diffusion coefficient on output power degradation is nonlinear.