Fault Diagnosis and Life Prediction of DC-link Aluminum Electrolytic Capacitors Used in Three-phase AC/DC/AC Converters

A very simple and low-cost strategy for the fault diagnosis and life prediction of DC-link aluminum electrolytic capacitors which is used in three-phase converters is presented in this paper. The main idea of this paper is to calculate the value of ESR and C using the inverter based on Recursive Least Square (RLS) method whenever the motor is stopped. The proposed strategy can provide a quick and accurate estimation of ESR and C with minimal hardware requirements. Theoretical analysis and simulation experiment are implemented to illustrate the efficiency of the proposed technique.