Equivalent Modeling Method of PV Cluster Converters Based on Grid-forming Control Strategy

In order to efficiently analyze the complex interaction between power grids and PV converters based on grid-forming control strategy, it is important to study the converter equivalent modeling method in electromagnetic transient environment. Based on the coherent equivalence criterion of synchronous generator, a converter homology judgment based on VSG control is proposed. Taking the photovoltaic converters with similar dynamic characteristics as the clustering principle, the feature points on the photovoltaic dynamic characteristics curve are extracted as the clustering index, and the fuzzy C-means clustering algorithm is used to divide the photovoltaic converters with similar dynamic characteristics into the same group. Finally, the photovoltaic converters in the same group are aggregated into an equivalent converter. In the real-time simulation environment of RT-LAB and Matlab/Simulink, the parallel simulation platform of multiple converters is built, and the dynamic response curves of the detailed model and the equivalent model are compared. The analysis results show that the equivalent model has high equivalent accuracy and simulation efficiency, thus verifying the correctness and feasibility of the proposed equivalent modeling method.