Abstract—This paper discusses experimental setups for health monitoring and prognostics of electrolytic capacitors under nominal operation and accelerated aging conditions. Electrolytic capacitors have higher failure rates than other components in electronic systems like power drives, power converters etc.
Aging laws of electrolytic capacitors. Many techniques deal with life forecast and failure detection of aluminum electrolytic capacitors which are utilized as a part of power electronic converters. The main idea of these techniques is to estimate the values of Equivalent Series Resistance (ESR) and Capacitance (C).
Aging is distinguished between the following changes in the capacitor performance: Change in capacitance, ESR and leakage current during operation (with voltage applied) and reduction of dielectric strength due to degradation of the dielectric (no voltage applied).
The present work shows the ESR and capacitance of the electrolytic capacitor as ageing indicators. It also shows how previous works intended to use these indicators to predict the lifetime. The disadvantages of the offline step in these works made it crucial to rethink a new 100% online method.
A total of 47 capacitors under test are used for this accelerated aging study. Measurements using an impedancemeter are done periodically during the accelerated aging test to characterize the frequency response of the capacitor’s impedance.
Therefore, the major factors affecting the lifetime of electrolytic capacitors in the power applications will be the operating temperature, the ripple current and the operating voltage. Other factors have minor affect to the lifetime and can be ignored in the calculation.