A three-dimensional TLM simulation method for analysis of thermal effect in the space solar panel

The ability of a PV module in spatial applications is to withstand the effects of periodic hot-spot heating that occurs when panel cells are operated under reverse biased conditions due to the properties of the cell's semi-conductor materials. Hot-spot is produced when one PV cell is partially shaded. The affected cell is forced into reverse bias (starting to dissipate power, with a consequent temperature increase). This can damage the cell encapsulation and eventually produce module failure. In addition, the thermal effect influences the estimation of the maximum power point (MPP) and electrical parameters for the PV modules, such as maximum output power, maximum conversion efficiency, internal efficiency, reliability, and lifetime. In this paper, the Transmission Line Matrix method (TLM) was used for first one in research to map the surface temperature distribution of solar panel in reverse bias mode. Two models have been considered: poly and amorphous silicon based cells to calculate the junction temperature for a given input power and to localise hot spots of the panel under power conditions. It was observed that some cells exhibited an inhomogeneity of the surface temperature resulting in localized heating. This can damage the cell encapsulation and eventually produce PV panel failure. The TLM technique has been successful in modeling various heat diffusion and mass transport problems and has proven to be efficient in terms of stability, complex geometries and the incorporation of non linear material properties. The three dimensional results show that the method has a considerable potential in PV panel thermal analysis and design.