【摘要】 为了提高双馈感应发电机(DFIG)次同步振荡(SSO)参数辨识精度和噪声适应性以及消除辨识中存在的模态混叠，提出一种改进变分模态分解(VMD)和最小二乘-子空间状态空间系统(TLS-N4SID)的DFIG的SSO参数辨识方法。基于VMD分解DFIG并网电流，并采用贝叶斯优化算法(BO)对VMD进行改进，获得最优本征模态函数(IMF)分解个数K和惩罚因子α,以消除分解中的模态混叠现象和提高噪声适应性。将得到的IMFs与并网电流进行互信息(MI)分析，选取出主导IMFs。重新采样主导IMFs并基于TLS-N4SID进行参数辨识，辨识过程中采用非支配排序遗传算法II(NSGA-II)对N4SID进行改进，获得最优信号子空间阶数b,以提高辨识精准性和噪声适应性，再结合TLS完成DFIG的SSO信号的参数辨识。通过复合信号、含双馈风电场的4机2区域的系统模型的时域仿真以及河北沽源风电场实际SSO数据进行分析，验证所提出辨识方法的有效性。更多还原

【Abstract】 In order to improve the accuracy of parameters identification and noise adaptability of sub-synchronous oscillation(SSO) for the doubly-fed induction generator(DFIG), as well as to eliminate mode aliasing in identification, an SSO parameters identification method for DFIG based on the improved variational mode decomposition(VMD) and the total least squares-numerical subspace state space system identification(TLS-N4SID) was proposed. The grid-connected current of the DFIG was decomposed using VMD. Bayesian optimization(BO) was employed to refine the VMD procedure by determining the optimal number of intrinsic mode functions(IMFs) K and the appropriate penalty parameter α, thereby eliminating mode aliasing and improving noise adaptability. The IMFs produced by the decomposition were evaluated through mutual information(MI) analysis with the original grid-connected current signal, allowing the dominant IMFs to be identified. The dominant IMFs were resampled and subjected to parameters identification using TLS-N4SID. During this process, the N4SID was improved by a non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ) to determine the optimal signal subspace order b, thereby enhancing identification accuracy and noise adaptability. The TLS method was employed to identify the characteristic parameters of the DFIG SSO signal. The proposed identification method was validated through tests on synthetic composite signal, time-domain simulations of a four-machine two-area system incorporating a DFIG-based wind farm, as well as real SSO records from the Guyuan wind farm in Hebei Province, all of which confirmed its effectiveness.更多还原