Reproducing wind-induced vibration of solar PV modules in the lab - without a dedicated wind tunnel

摘要

One of the greatest challenges facing the photovoltaic (PV) module business is overall reliability when exposed to the outdoor environment for up to 25 years. The single biggest contributor to poor reliability has been identified as micro-cracks in the silicon base structure that will propagate as a function of excitation. Such crack propagation is known to worsen with thermal stresses and also with wind-induced vibration. This latter topic has been very little studied in the overall reliability enhancement efforts to date. One of the reasons that wind-induced vibration has not been well studied is the perceived need for a wind tunnel associated with the laboratory conducting the studies. Wind tunnels in general are rare and very expensive. In 2010-2011, Westpak undertook a study to show that vibration test equipment could be used to duplicate the same excitation on solar modules as that experienced during outdoor wind exposure. When a solar module is analyzed as a spring-mass system, it becomes apparent that the system will respond to any excitation at its natural frequency, whether that excitation is a result of wind, mechanical forces, or any other excitation source.