Abstract: An aging status diagnostic apparatus for a power conversion system and diagnosing method thereof are provided. The apparatus includes an output current sensing means detecting output current of an inverter switching module; and a measurement and diagnosis means receiving the output current, calculating one or more average values of the output current over one period, and magnitude or effective value of each harmonic of the output current, and determining whether aging of the inverter switching module has occurred. Furthermore, the measurement and diagnosis means determines that the aging of the inverter switching module has occurred if the average value of the output current over one period increases by a value equal to or greater than a predetermined range and/or an even order harmonic or a specific order harmonic based on FFT (Fast Fourier Transform) of the output current increases by a value equal to or greater than a predetermined range.

Abstract: The present invention relates to an apparatus capable of diagnosing the aging state of a power conversion system at ordinary times and its diagnosing method to ensure the reliability of a power conversion system. The apparatus includes a current sensing means for detecting the output current of a inverter switching module or an electrolytic capacitor, and measurement and diagnosis means for extracting elements related to the aging status of the power conversion system by receiving the output current waveform of the inverter switching module and magnitude of each harmonic or an impedance voltage signal of the electrolytic capacitor. Furthermore, it is preferable that the apparatus further includes a measurement current generation means for generating measurement current to be supplied to the electrolytic capacitor.