METHOD AND SYSTEM FOR ON-LINE MONITORING AN ELECTROLYTIC CAPACITOR CONDITION

摘要

The present invention concerns a method for on-line monitoring an electrolytic capacitor condition. The method comprises the steps of:-measuring a voltage ripple across the electrolytic capacitor and the current ripple flowing through the electrolytic capacitor;-measuring the temperature of the electrolytic capacitor;-emulating the monitored electrolytic capacitor using a capacitor model comprising a capacitor and a solid state adjustable resistor,- applying one of the measured ripple to the capacitor model,-adjusting the solid state adjustable resistor to minimize the error between an estimated ripple provided by the capacitor model and the other measured ripple not applied to the capacitor model,- estimating an equivalent series resistance of the monitored electrolytic capacitor using value of the solid state adjustable resistor.-determining an end of life limit value as a function of the temperature of the electrolytic capacitor and an initial equivalent series resistance of the monitored electrolytic capacitor ;-comparing the estimation of the equivalent series resistance of the monitored electrolytic capacitor with the end of life limit value.