Reliability Estimation of Three Single-Phase Topologies in Grid-Connected PV Systems

This paper presents the reliability estimation of the power stages in three grid-connected photovoltaic systems. The circuits analyzed are an integrated topology, a two-stage configuration, and a three-stage one, all commutating in the hard-switching mode. The reliability-related parameters, such as the failure rate, are calculated following the procedure outlined in MIL-HDBK 217. A comparison between the topologies is performed, and both the components and the stress factor with the highest contribution to the failure rate are identified. The methods to calculate junction temperature variations are included.