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US 12,650,477 B2Granted
Method for evaluating the degradation level of capacitors of a power filter, adjustable speed drive and power converter provided for performing the method
AssigneeDanfoss Power Electronics A/S
InventorsLucian Asiminoaei, Luzia Almeida, Jörg Dannehl, Sanjeet Kumar Dwivedi, Norbert Hanigovszki
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Abstract
The present invention is directed at a method for evaluating the degradation level of capacitors of a power filter connected to an adjustable speed drive (ASD) or a power converter. The invention is also directed at an adjustable speed drive and a power converter provided for performing the method.
Claims19
A method for evaluating the degradation level of one or more capacitors (Cf) of a power filter connected to an adjustable speed drive (ASD) or a power converter, the method comprising:
- injecting a degradation-determining controllable disturbance comprising an AC signal into the power filter or the adjustable speed drive (ASD) or the power converter;
- measuring a response to determine a degraded resonance frequency (fresDegraded) of the power filter;
- and
- calculating the degradation level of the one or more capacitors (Cf) based on a comparison of a baseline resonance frequency (fresBaseline) of the power filter and the degraded resonance frequency (fresDegraded);
- wherein the degradation level of the capacitor (Cf) is determined from the equation:
- Degradation
- =
- 100
-
- (
- f
- resBaseline
- f
- resDegraded
- )
- 2
- [
- %
- ]
- .
17 more elements
Dependencies are inferred from the claim text.