Correlation of accelerated lifetime in punctured capacitor with normal operating lifetime

Aluminum electrolytic capacitors (AECs) are widely used in power electronic converters for filtering, buffering, bypass and storage purpose. Typical service life of AECs varies between 1,000 to 12,000 hours at rated condition. Operational life of these capacitor decreases due to various electrical and environmental parameters, thereby limiting the life of the converter system. Typically, capacitors are tested by the manufacturer at elevated parameter (voltage, temperature etc.) above the maximum rating and suitable acceleration multipliers available from testing are used to assess the operational life of AECs in operating condition. These methods require large time for the degradation of the capacitor. Accelerated life tests based on puncturing of capacitor seal, could reduce the testing time. The objective of this paper is to determine the correlation between degradation during the accelerated life test and actual degradation of the capacitor operating under normal conditions. This would be useful during design of the power electronic converters based on AECs. Accelerated life tests using puncturing and elevated temperature techniques are carried out. Experimental results are presented in this paper.