Multi-ports Modular Frequency-Domain Modeling Method of Wind Power Generation Systems

The wind power converter is always accompanied by multiple frequency harmonics when participating in the oscillation. The multi-harmonic interaction leads to the coupling between wind power generation equipment or its internal power electronic converters, which makes the frequency domain modeling of large-scale wind power generation system (WPGS) difficult. To address this issue, this paper develops a multi-port modeling (MPM) method. The multi-port model not only can accurately embody the multi-harmonic characteristic of power electronic devices or systems through extending the single frequency port variable of the classical two-port model (CTPM) to the multi-frequency harmonic port variable, but also realize the modular aggregation. Besides, a network function-based stability analysis technique is then put forward to study oscillation. Finally, the effectiveness of multi-port impedance model and analysis method are validated against the MATLAB/ Simulink testbed of doubly-fed induction generator (DFIG)-based wind power system.