A new power locus for the p-q operation of series connected 12-pulse current source controlled converters

The series connected 12-pulse current source converter can operate under controlled p-q operation with symmetrical or asymmetrical firing of the two series connected 6-pulse thyristor converters. The input power factor and input current total harmonic distortion (THD) are dependent on the converter power locus. In this paper, a new p-q locus is introduced where the maximum reactive power absorbed by the converter is halved, simultaneously providing minimum input current THD. The input current THD and power factor of the converter are investigated based on the proposed power locus. A compensation technique is mandatory in order to improve the performance. The proposed power locus reduces the compensator rating. The power locus performance of the 12-pulse converter is simulated and verified experimentally.