Harmonic modeling of a cluster of ac/dc converters with an approach to compute overlap angles in presence of simultaneous commutations

In order to evaluate with good accuracy current harmonics generated by several ac/dc converters connected to a common feeder, care must be taken when evaluating overlap angles due to simultaneous commutations. The proposed approach for overlap angle determination is carried out based on the equivalent circuit of the converters during commutation. A simplified approach is proposed that takes into account the input reactance of converters in commutation and the reactance of the common feeder. This simplified approach allows to significantly reduce computation time compared to the time required for the simulation of the full equivalent circuit, without compromising precision. The dc ripple is considered. It is shown that if simultaneous commutations are not taken into account, a large error is introduced in the computation of the overlap angles and the current harmonics.