US 2010/0161259 A1 · AGING STATUS DIAGNOSTIC APPARATUS FOR POWER CONVERSION SYSTEM, AND METHOD THEIR OF

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. By analyzing an average value or the magnitude of harmonics by FFT analysis of the output current waveform of the inverter switching module and measuring an ESR value or a loss angle tan δ of a DC bus of the power conversion system, the present invention is able to monitor and diagnose the abnormal state attributable to the aging or degradation of the power conversion system in advance.

Claims32

Dependent claims

An aging status diagnostic apparatus for a power conversion system, comprising:

an output current sensing means installed on an output stage line of an inverter switching module of the power conversion system, and configured to detect output current of the inverter switching module;
and
a measurement and diagnosis means configured to receive the output current of the inverter switching module from the output current sensing means, calculate one or more of an average value of the output current over one period, and magnitude or an effective value of each harmonic of the output current, and determine whether aging of the inverter switching module has occurred.

An aging status diagnostic apparatus for a power conversion system, comprising:

a measurement current generation means connected to + and terminals of a DC bus electrolytic capacitor of the power conversion system, and configured to generates a measurement current signal to be supplied to a DC bus electrolytic capacitor;
a signal isolation unit configured such that the measurement current signal generated by the measurement current generation means is blocked from DC stage voltage and flows through the electrolytic capacitor;
a measurement and diagnosis means configured to calculate one or more of an ESR value and a loss angle of the electrolytic capacitor by using the measurement current signal generated by the measurement current generation means, and an impedance voltage signal induced to the electrolytic capacitor by the measurement current signal, and determine whether the aging of the DC bus electrolytic capacitor of the power conversion system has occurred.

A method of diagnosing an aging state of a power conversion system in an aging status diagnostic apparatus for the power conversion system, comprising the steps of:

(a) in the aging status diagnostic apparatus for the power conversion system, causing a measurement current signal having a predetermined frequency to flow through a DC bus electrolytic capacitor connected to a DC bus of the power conversion system;
(b) extracting an impedance voltage waveform corresponding to the measurement current signal at + and − terminals of the electrolytic capacitor;
and
(c) in the aging status diagnostic apparatus the power conversion system, calculating one or more of an ESR value and a loss angle tan δ of the electrolytic capacitor, and determining whether the aging of the DC bus electrolytic capacitor has occurred.

1 more element

Dependencies are inferred from the claim text.

Aging status diagnostic apparatus for power conversion system, and method their of

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Aging status diagnostic apparatus for power conversion system, and method their of

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Abstract

Claims32