Synchronous Stability Analysis Model of Grid-following Converter Based on Singular Perturbation Method

As a high-order nonlinear system, the dynamic characteristics of the grid-following converter are complex and the PIs' parameters are difficult to configure. In order to overcome this problem, a normalized singular perturbation model is established for the first time to make analysis and parameter design more convenient. And then, phase-locked loop dynamics at intermediate speeds are considered and a reduced order model is developed. Meanwhile, some parameter design ranges required for model reduction are given. The effectiveness of the proposed model and the correctness of the parameter design have been validated.