Electrolytic capacitor life testing and prediction

The aluminum electrolytic capacitor is widely used in various power electronic circuits and systems such as 3-phase PWM inverters. Its functions include, bus voltage stabilisation, conduction of ripple current due to switching events, etc. In automotive applications, one of the big issues is the extreme and harsh temperatures they have to withstand, underhood, which during the summer months would reduce their life. Most of the capacitors have maximum temperature ratings of either 85 or 105°C and a few are rated at 125°C. According to literature found, one of the primary wear-out mechanisms in electrolytic capacitors is mainly due to the loss of electrolyte by vapor diffusion through the seals. Other reports suggest that the main wearout mechanism is deterioration of the electrolyte. Experiments conducted to date and the results from the same are compared against modeling results based on a model reported in literature