计其源端特性的构网型直驱风机稳定性分析

Stability analysis of grid-forming direct-drive wind turbine considering source characteristics

摘要:

为准确描述构网型直驱风机的动态特性,并分析其在不同电网强度下的稳定性,考虑风机源端特性对系统进行小信号建模。首先,基于状态空间建模方法,详细构建了基于虚拟同步机控制的构网型直驱风机全系统小信号模型,并通过仿真测试验证了所建小信号模型的准确性。其次,通过特征模态分析,研究了不同电网强度对系统稳定性的影响,评估其在弱电网环境下的适应性。同时,分析风速阶跃扰动对系统低频振荡的诱发机制,探讨系统结构参数（如直流侧电容）及控制器参数对系统动态性能的影响。最后,基于RT-LAB半实物仿真平台搭建系统模型,验证了模型在实时仿真环境下的响应能力和准确性。结果表明,构网型直驱风机在弱电网条件下具有较强的适应性,但在风速阶跃扰动下易诱发低频振荡。此外,合理调整系统结构参数和优化控制器参数可有效抑制低频振荡,提高系统在弱电网环境下的稳定性。本研究为构网型风电机组的动态特性分析提供了一种系统性的建模方法,并为进一步优化其稳定控制策略提供了理论支持。

Abstract:

To accurately describe the dynamic characteristics of grid-forming direct-drive wind turbines and analyze their stability under different grid strengths, this study considers the source-side characteristics of wind turbines and conducts small-signal modeling of the system. First, based on the state-space modeling method, a comprehensive small-signal model of the entire grid-forming direct-drive wind turbine system with virtual synchronous generator (VSG) control is constructed, and its accuracy is verified through simulation tests. Second, eigenvalue-based modal analysis is employed to investigate the impact of different grid strengths on system stability and assess its adaptability in weak grid environments. Additionally, the mechanism of low-frequency oscillations induced by wind speed step disturbances is analyzed, along with the effects of system structural parameters (such as DC-side capacitance) and controller parameters on the systems dynamic performance. Finally, an RT-LAB hardware-in-the-loop simulation platform is used to build the system model, validating its response capability and accuracy in real-time simulation environments. The results indicate that grid-forming direct-drive wind turbines exhibit strong adaptability in weak grid conditions but may prompt low-frequency oscillations under wind speed step disturbances. Moreover, properly adjusting system structural parameters and optimizing controller parameters can effectively suppress low-frequency oscillations and enhance system stability in weak grid environments. This study provides a systematic modeling approach for analyzing the dynamic characteristics of grid-forming wind turbines and offers theoretical support for further optimizing their stability control strategies.