Integrating photovoltaic inverter reliability into energy yield estimation with Markov models

Markov reliability models to estimate Photovoltaic (PV) inverter reliability are proposed for utility-interactive systems. These are then extended to generate a unified PV energy-yield model. The integrated reliability-energy yield framework is superior to conventional methods as it accounts for inverter failures and repairs. The proposed analytical framework is utilized to compare conventional central inverter architectures to emerging architectures that employ microinverters. Case studies applied to a 9 kW residential system indicate that over a 25 year period, in typical operating conditions, microinverters provide higher energy yield as compared to a conventional system. Additionally, the analysis demonstrates that the energy yield is more sensitive to the repair time compared to the mean time to failure of the inverters.