Reliability evaluation of an impedance-source PV microconverter

The reliability of an impedance-source PV microconverter is evaluated based on the real-field mission profile. As part of a PV microinverter, the dc-dc microconverter is firstly described. Then the electro-thermal and lifetime models are built for the most reliability-critical components, i.e., the power semiconductor devices and capacitors. The finite element method (FEM) simulation is used for the thermal impedance extraction. The mission profile, i.e., the ambient temperature and solar irradiance, from Aalborg, Denmark is applied to the built electrothermal model. Finally, the thermal loading profiles and annual wear-out damage accumulation are obtained. In addition, experimental measurements from a 300-W converter prototype are given.