An Online technique for estimation of the C and ESR of DC link capacitor in a boost converter based on multiple harmonic injection

Abstract

Aluminium Electrolytic capacitors (AEC) are widely used in DC-DC converters. Health of the capacitor can be monitored using the capacitance and equivalent series resistance (ESR) as the ageing will decrease the capacitance and increase the ESR. Hence the estimation of these parameters is essential for the diagnosis of AEC. So, in this paper a method for the estimation of the capacitance and ESR are proposed. This method is based on the injection of low frequency current harmonics into the converter by modifying the duty ratio. A group of harmonic currents are injected, and corresponding voltage and current ripples are obtained using DFT analysis which is used to calculate the impedance at each frequency. From these impedances the capacitance and ESR are estimated using Least Mean Square (LMS) algorithm. Detailed simulation is carried out using MATLAB/Simulink and results are included in this paper. © 2023 IEEE.