基于自适应惯量阻尼的构网型直驱风机动态频率支撑策略

Dynamic Frequency Support Strategy for Grid-Forming Direct-Drive Wind Turbines Based on Adaptive Virtual Inertia and Damping

中文关键词:构网型控制  直驱永磁同步风机  虚拟同步发电机  特征根轨迹分析  自适应控制策略

keywords:grid-forming control  direct-drive permanent magnet synchronous generator wind turbine  virtual synchronous generator  root-locus analysis  adaptive control strategy

中文摘要:针对构网型直驱永磁同步风机在阶梯风速扰动及电网故障下的功频失稳问题，提出一种基于虚拟惯量与阻尼系数的协同自适应控制策略。该策略以频率偏差及其变化率为双输入信号，设计分阶段非线性自适应调节律：在频率跌落阶段增大虚拟惯量、恢复阶段增强阻尼，实现分阶段解耦控制，并引入阈值平滑策略以避免参数频繁切换。基于特征根轨迹法分析虚拟参数对系统主导极点的影响规律，确立自适应整定规则。通过仿真平台，在典型弱电网条件下的构网型直驱风机单机并网系统中进行多工况仿真验证。结果表明，所提策略能够有效应对阶梯风速、负荷突增及电网故障等复杂工况，提升系统运行的功频稳定性；相较于其他控制策略，所提策略具有更强的动态鲁棒性与主动频率支撑能力，可获得更小的暂态频率偏差与更平滑的功率恢复过程。

Abstract:To address the power-frequency stability challenges faced by grid-forming direct-drive permanent magnet synchronous wind turbines under step wind speed disturbance and grid faults，this paper presents a coordinated adaptive control strategy based on virtual inertia and damping coefficient. This strategy takes frequency deviation and its rate of change as dual input signals，constructs a phased nonlinear adaptive law，enhances virtual inertia in the frequency drop phase and strengthens damping in the recovery phase to realize phased decoupling control，and it also introduces a threshold smoothing mechanism to avoid frequent parameter switching. The influence law of virtual parameters on the dominant poles of the system is revealed based on the root-locus method，and the adaptive tuning criterion is established. Multi-condition simulation verification is carried out on the single-machine grid-connected system of grid-forming direct-drive wind turbines under typical weak grid conditions through the simulation platform. The results show that the proposed strategy can effectively cope with complex disturbances such as step wind speed，sudden load increase and grid faults，and improve the power-frequency stability of system operation；compared with other control strategies，the proposed strategy has stronger dynamic robustness and active frequency support capability，and can obtain smaller transient frequency deviation and smoother power recovery process.