Study of AC-module inverters under extreme desert conditions

We present some results of a high-statistics study of the performance and characteristics of NKF OK4E-100 “AC-module”-type inverters under extreme desert conditions. The work was carried out at the Ben-Gurion National Solar Energy Center, located in the Negev Desert. Twenty inverters were monitored for one complete year. Ten of them were each fed by pairs of 40 W Solarex SX146 PV modules, in order to provide a set of “normal operation” systems. The other 10 were fed by quartets of similar 40 W PV modules, in order to create frequent situations of extreme overload. The paper addresses hourly, daily and seasonal inverter efficiencies; optimal module sizing; overload penalties; temperature effects; light-threshold effects; quality control issues and failure rates.