Abstract
In a 3-phase power supply, analysis of a 3-phase spectrum can be done using a conventional single-phase spectral analyzing method. However, precise analysis of the 3-phase spectrum is difficult by the conventional analyzing method. For instance, the conventional single-phase analytic method cannot distingish between positive-phase-sequence and negative-phase-sequence in the 3-phase power supply. To solve above problem, this paper proposes a novel analytic method on a low-pass filter using rotating coordinate transformations. The proposed analytic method is quite effective for anlysis of the 3-phase spectrum.