Lifetime enhanced modulation method for unbalanced loss issue in sustainable renewable converters

Abstract

The increasing power losses in renewable energy converters can accelerate the degradation of power modules and reduce system reliability. This article proposes an enhanced modulation method to address the unbalanced loss distribution in typical renewable converter modules. The approach periodically adjusts switching operation modes to equalize power losses and average the junction temperature of power devices. A full-bridge inverter module is used to demonstrate the method, and experiments confirm that it achieves a more balanced loss distribution compared with traditional modulation. Reliability analysis based on Weibull function-derived time-to-failure distributions and annual mission profiles of a 5 kW photovoltaic (PV) system in Arizona shows that the proposed method can significantly extend the lifetime of power modules without increasing system cost. Furthermore, life cycle assessment (LCA) shows that the proposed method prevents at least two module replacements over a 25-year service life, reducing environmental impact. By improving module longevity, the method also contributes to the overall sustainability of renewable converters.