基于EMD和TLS-Prony的次同步振荡模态辨识方法及电压反馈抑制策略

SUB-SYNCHRONOUS OSCILLATION MODAL IDENTIFICATION METHOD BASED ON EMD AND TLS-PRONYALGORITHM AND VOLTAGE FEEDBACK SUPPRESSION STRATEGY

以减小次同步振荡模态辨识中的误差,提升Prony算法的抗噪性,抑制双馈风电机组并网次同步振荡为研究对象,提出一种基于经验模态分解(EMD)和TLS-Prony算法的次同步振荡模态辨识方法及电压反馈抑制策略。首先,使用EMD对振荡信号进行预处理,降低噪声对Prony算法辨识振荡模态的影响;然后,使用TLS-Prony算法进一步抑制噪声干扰,提取振荡特征,辨识振荡模态;最后,直接调整控制参数调制网侧变流器的输出电压,向系统注入等效正电阻,改善系统负阻尼特性,设计以串补电容电压为反馈输入信号的附加阻尼控制器。采用模态计算分析附加阻尼对系统稳定性的影响,基于Matlab/Simulink仿真平台验证所提阻尼抑制策略的有效性。

Based on the suppression of grid-connected sub-synchronous oscillation of doubly fed induction generator.In order to reduce the errors in the modal identification of sub-synchronous oscillation and improve the anti-noise performance of Prony algorithm,this paper proposes a modal identification method of sub-synchronous oscillation based on empirical mode decomposition(EMD)and TLSProny algorithm and a voltage feedback suppression strategy.Firstly,EMD is used to preprocess the oscillation signal to reduce the impact of noise on the identification of oscillation modes by Prony algorithm.Then,the TLS-Prony algorithm was used to further suppress the noise interference,extract the oscillation features,and identify the oscillation modes.Finally,the output voltage of the grid-side converter is modulated directly by adjusting the control parameters,and the equivalent positive resistance is injected into the system to improve the negative damping characteristics of the system.An additional damping controller is designed with the cascade capacitor voltage as the feedback input signal.The influence of additional damping on the stability of the system is given by modal analysis,and the effectiveness of the proposed damping suppression strategy is verified by Matlab/Simulink simulation platform.