Inverters' self-checking monitors for reliable photovoltaic systems

Photovoltaic systems are a widespread form of green energy, that is becoming increasingly considered also as a form of economical investment. Their reliability is consequently becoming a concern. In this paper we focus on the reliability of the DC-AC converters (inverters) of photovoltaic (PV) systems. We analyze the effects of the faults likely to affect their operation in the field. We show that such faults can impact catastrophically the power delivered to the load. We then propose a self-checking monitor, that is able to detect the occurrence of such faults in the field, as well as faults possibly affecting itself. Our monitor can therefore be adopted to guarantee the concurrent on-line test of faults affecting the inverters of PV systems. Moreover, if used together with suitable recovery strategies, for instance based on proper hardware reconfiguration, it can provide PV systems with fault tolerance ability, thus meeting the increasing demand for reliable PV systems.