Electrolytic Capacitor Degradation Monitoring using an On-line Parameter Estimation Scheme involving Sliding Mode Differentiators and a Kalman Filter

An indication of electrolytic capacitor gradual degradation may be obtained by observing an increase in the equivalent series resistance (ESR) and a decrease in capacitance over time. On-line condition monitoring of these two electrical parameters allows for early detection of the capacitor ageing that can reduce catastrophic failure and their costly consequences. In this paper, a parameter estimation scheme consisting of sliding mode differentiators and a Kalman filter is proposed for electrolytic capacitor degradation monitoring. Satisfactory on-line estimation of the ESR and capacitance under noisy conditions is achieved with the proposed approach as demonstrated through computer simulation results.