A Contribution Towards a General and Systematic Procedure for Modeling Line Commutated AC/DC Converters in the Harmonic Domain

Under certain nonideal conditions, harmonic domain models for ac/dc converters require a high level of detail and complexity in order to reproduce low-frequency interactions. In these cases, not only must the representations of the dc ripple but also the behavior of the dc current controller and the structure of the dc side be included. These aspects have been considered in previous works, where the converter operating point (COP) is only defined in terms of dc magnitudes. This paper present several refinements and improvements for modeling this kind of device. It is achieved by means of a systematic method where passive and active dc loads of any structure can be considered, controlled and uncontrolled converters can be modeled, and the COP can be defined in terms of ac or dc magnitudes. With this, great flexibility and accuracy for modeling line-commutated ac/dc converters are obtained.