并网变流器全工况阻抗模型的黑箱辨识方法OA北大核心CSTPCD

Impedance-based analysis has become an important choice for engineering for evaluating the risk of broadband oscillation.This is because it adapts to the black-box system with unknown parameters or control structure of grid-tied converters.In this paper,the grid-following three-phase two-level converter is taken as an example.First,using harmonic linearization,the open/closed-loop theoretical full operating condition AC impedance model(IM)considering the DC coupling is rigorously deduced.In particular,the model parameters and the high-order terms of operating points are fully decoupled.Secondly,based on the features of the theoretical model,the basic principle of the black box identification method is clarified,and the numbers of operating conditions for identifying a single frequency response of the open/closed-loop IM is analyzed.Using the identified full operating condition IMs,rapid evaluation of the safe operation area of the system under various short-circuit ratios is realized,and the accuracy is verified by time domain simulations.In addition,the rationality and universality of the proposed method as well as its superiority over deep learning methods are discussed.This provides a reference for the practical application of the impedance-based method.