A decision system for electrolytic capacitors diagnosis

Abstract

Phone: 133 4 72 1 8 6 I 03 -olivier.ondel~,ec-lyon.fr I:%: +33 4 i a 43 37 17Abstract-Electrolytic filter capacitors are Irequently responsible for static converters breakdowns. The rise of temperature within capacitor is the most significant factor upon ageing and so lifespan . To predict the ageing of the capacitor, a method of predictive maintenance has been developed . It consists in monitoring the voltage ripple of the capacitor. This ripple is the hest indicator of its worn state. It is function of parameters such as input voltage, output current and ambient temperature. A reference system taking into account all these parameters is determined Cor sound capacitors. We will deduce that the dispersion of input voltage had a weak influence upon voltage ripple compared to other parameters such as output current and ambient temperature. And precisely the temperature its being an influent parameter in the diagnosis, measurement must he very relevant. That is why we will measure the internal temperature of capacitor which takes into account the ambient temperature hut also the internal heating of capacitor. This measurement will he done in an environment not confined for not which is distorted. We will check then the relevance of our modifications by comparing our results with the actual values of the state of capacitors deduced using a bridge RLC.

Condition Monitoring of DC Link Electrolytic Capacitors in Adjustable Speed Drives

“…The traditional method for preventive maintenance of electrolytic capacitors is to remove the capacitor and measure the value of C for diagnostics purposes [4]. However, since it is inconvenient and difficult to make an accurate assessment due to variation of C between capacitors, many advanced techniques for assessing the condition of the capacitor have been proposed in [4][5][6][7][8][9][10].…”

“…An on-line monitoring technique for the output capacitor of dc power supplies based on ∆V c is proposed in [8][9]. The influence of temperature, output load current, and input voltage variations on ∆V c are taken into account in this work to obtain an accurate estimate of ESR due to capacitor degradation.…”

“…The main disadvantage of electrolytic capacitors is its finite lifetime and high failure rate due to wear-out degradation failure. It has been reported in many resources that they are one of the weakest components in power electronics converters [1][2][3][4][5][6][7][8][9][10]. According to a failure survey on two different types of switch mode power supplies, 60% and 72% of the power supply failures were due to electrolytic capacitor breakdown [1].…”

A Real Time Predictive Maintenance System of Aluminium Electrolytic Capacitors Used in Uninterrupted Power Supplies

“…It's known that the common faults in electrolytic capacitor include initial catastrophic failures due to manufacturing or misapplication defect, and wear-out faults which cannot be avoided. Unfortunately, electrolytic capacitors are one of the weakest components in power electronics converter [1][2][3][4][5][6][7][8][9][10][11][12][13]. For example [1], [4], in Uninterrupted Power Supplies (UPS), they are responsible in about 50% cases of power electronics component failures.…”

“…They also depend on the ambient temperature where the converter operates. Many papers have proposed different methods or algorithms to determine the ESR and/or capacitance C of the electrolytic capacitor [2][3][4][5][6][7][8][9][10][11][12][13]. However, many parameters such as off-line additional measurements and many computations are required, which makes it complicated, difficult, expensive and impractical for actual application.…”