Output stage capacitor aging detection of grid connected isolating DC-DC converter

Reliability is one of the key features that is sought after in converter design. Electrolytic capacitors are the most common capacitor type in switching mode power supplies to be used as a DC bus energy storage. However, electrolytic capacitors are known to degrade due to aging. This paper introduces a capacitance degradation detection method for a step-down DC-DC converter that is based on introducing a voltage transient to the output voltage. The method is based on analyzing the voltage step response. The method was verified to be feasible with experimental tests with a grid connected step-down DC-DC converter.