On the Relation of Nodal Admittance- and Loop Gain-Model Based Frequency-Domain Modal Methods for Converters-Dominated Systems

Frequency-Domain (FD) modal method is a useful tool for oscillation analysis of converters-dominated systems. In this regard, the nodal admittance and loop-gain models are often applied, and both have their respective eigen-sensitivity-based Participation Factor (PF) analysis methods. Therefore, a question on how are they related or differed naturally arises, to this end, this letter uncovers and establishes the mathematical relation of the two FD-PF methods by introducing the Time-Domain (TD) eigen-sensitivity as the “bridge”. Then, the correctness of the relation is validated by numeric case studies of a converters-interlinked system. Aside from this main finding, other discussions on the TD/FD eigen-sensitivity are also helpful for the promotion of modal methods, e.g., facilitating cross-domain modal analysis.