A Switch Model for Emulation of Zero Current Switching in Dynamic Phasor

In the context of the increasing penetration of converter-based devices, the investigation of the transient behavior of power systems is increasingly important. As an alternative to classical electromagnetic transient simulations (EMT), simulations in the dynamic phasor (DP) domain, also known as Shifted Frequency Analysis (SFA), can be used. Due to the transformation involved in this methodology, a possible zero crossing in the 50/60 Hz signal cannot be inferred from the instantaneous values in the simulation and therefore zero current switching (ZCS) cannot be implemented conventionally. Thus, the simulation of switching events may result in unrealistic transients. In this paper, a method for modeling zero current switches in the dynamic phasor frame is presented. To approximate a ZCS, we propose the replication in the form of a variable resistor during the switching process. Comparison with conventionally used instantaneous switching in dynamic phasor shows a significant improvement. By examining distinctive designs of the methodology and comparison with EMT simulations, deviations and remaining shortcomings are highlighted.