An Online Parameters Monitoring Method for Output Capacitor of Buck Converter Based on Large-Signal Load Transient Trajectory Analysis

Aluminum electrolytic capacitor (AEC) is one of the weakest components in power electronic converters. As degradation AEC happens, its equivalent series resistance (ESR) increases and capacitance ( C) decreases. Therefore, online monitoring ESR C to predict AEC's life has great significance for ensuring safe reliable operation In this article, an scheme proposed buck converters, aiming estimate at output side. The utilizes large-signal load transient trajectories parameters a relatively low sampling frequency. By analyzing relationship between trajectory parameters, directly calculated using voltage current step values initial instant transient. Furthermore, utilizing calculation model derived from output-voltage trajectory. Corresponding simulation analysis system implementation are provided. 48-12-V converter with digital proportional-integral (PI) controller analog V 2 built verify estimation method. experimental results estimated consistent measured by LCR meter, error less than 10%.