Reliability Analysis Framework for a Grid-Tied PV-Battery System: Influence of PV and Battery Degradation on Reliability of Power Electronic Systems

Abstract

This paper presents a flexible framework to evaluate the reliability of power electronic systems used within a grid-connected PV-battery system. As a practical example to show the capability of this framework, the life consumption (LC) of power semiconductors (IGBTs and diodes) is determined considering both solar panel and lithium-ion battery degradation. Different panel degradation rates can be defined to the framework. The battery degradation is calculated by a closed-loop approach so that the battery degradation is adjusted based on the determined cycling and calendar aging. The outputs are obtained for three cases: (1) no degradation, (2) only PV degradation, and (3) both PV and battery degradation. The results showed that by considering the battery degradation, the battery DC-DC converter’s switches will experience 14% lower LC compared to the case with both PV and battery degradation models, while the switches within the PV inverter have 2.3% higher LC when considering the battery degradation.