A Noninvasive Online Evaluation Method for Core Temperature of Aluminium Electrolytic Capacitors

This letter proposes a nonintrusive online estimation method for the core temperature of aluminum electrolytic capacitors (AECs). Based on the linear capacitance-temperature relationship in AECs, the core temperature is estimated by easily measured changes in case temperature. An algorithm for online obtaining and updating capacitance-temperature coefficients is given to realize real-time evaluation of the core temperature for AECs. Experiments verify the feasibility and accuracy of the proposed method. The estimated core temperature can be further used as an input for capacitor lifetime evaluation and safe operation threshold.