Concept and Analysis of a 12-Pulse Transformer with Built-in Passive Harmonic Filter

Inhalt:
Variable frequency drives with 12-pulse rectifiers typically require additional filtering in order to comply with power quality standards. This paper introduces an efficient way to incorporate a trap filter into the supplying transformer. Besides the description of the solution, the focus is directed towards the analytic description of the system, linking the winding construction with the magnetic and electrical properties, as well as with measurement data taken on the transformer terminals. The presented results are instrumental to optimally design the integrated filter by properly arranging the transformer windings.