Schmidhauser Ag

Andreas Schrepfer

A detection of a failure of a phase (as a method and apparatus) in a system&#x2014;supplied by multiple phases&#x2014;including a DC link () is suggested. A rectified voltage () of the DC link () pulses at a multiple of the mains frequency as a fundamental wave. The rectified voltage () is filtered for detecting a signal component at the double frequency of the mains frequency (). The rectified voltage () is also 'filtered' for detecting an average link voltage (). A ratio signal () is formed as a ratio of the average link voltage () to the signal component at the double frequency of the mains frequency (). An error detection signal () results from a comparison of the ratio signal () with an error threshold ().

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Wittenbach, Switzerland

Andreas Schrepfer