An Online Monitoring Method for Output Capacitors of DC/DC Boost Converters

Electrolytic capacitor (E-Cap) is one of the most vulnerable components in power electronic converters. Monitoring the health status of E-Caps and scheduling maintenance before serious break down occurs have great significance to ensure the reliability of power electronic systems. As the degradation of E-Cap happens, its capacitance (C) decreases. Based on this, this paper proposes an online capacitance monitoring scheme for dc/dc boost converters. The proposed scheme uses the large-signal transient voltage trajectory to estimate C, and has a relatively low sampling frequency. Taking a 24 V/48 V boost converter with resistive loads as a case study, experimental results demonstrate the feasibility of the proposed scheme with the estimation error of less than 3% for the considered case studies.