Comprehensive switching functions approach to calculate harmonics produced by multipulse thyristor converters operating under unbalanced supply

This paper describes how a comprehensive switching functions approach can be used to calculate both AC and DC harmonics produced by multipulse thyristor converters operating under nonideal supply conditions. Calculations include unbalanced voltage supply, asymmetric commutating impedances and phase-shift imbalances between transformers. The proposed approach enables easy incorporation of both the zero crossing and the equally spaced firing pulse methods. The validity of the proposed approach is demonstrated by comparison with the results of time domain simulation