针对弱电网下的跟网型变流器（GFL-VSC）,在计及直流电压控制（DVC）影响的条件下,研究其稳定运行及同步控制策略。首先,建立考虑DVC的GFL-VSC大扰动模型。在此基础上,通过类比传统同步发电机转子功-角摇摆方程,推导出系统阻尼比,从而反映出电网电压跌落故障下系统的暂态失稳机理和影响因素,通过绘制系统功率-电流曲线分析系统平衡点的存在性和稳定性。进而,提出一种基于锁相环自适应参数和功角补偿及可变角速度的GFL-VSC暂态稳定性提升方法。最后,Matlab/Simulink仿真结果证明了暂态稳定分析的准确性和所提控制策略的有效性。
Abstract
Considering the influence of DC-link voltage control（DVC）, the stable operation and synchronization control strategy of grid-following converters under weak grid conditions are studied. Firstly, a large disturbance model of grid-following converters with consideration of DVC is established. Based on this, by analogy with the rotor angle oscillation equation of traditional synchronous generators, the damping ratio of the system is derived, reflecting the transient instability mechanism and influencing factors under large disturbances. The existence and stability of the system equilibrium point are analyzed by drawing the power-current curve of the system. Then, a transient stability enhancement method for GFL-VSC based on phase-locked loop adaptive parameter, power angle compensation, and variable angular velocity is proposed. Finally, the simulation results of Matlab/Simulink prove the accuracy of the transient stability analysis and the effectiveness of the proposed control strategy.
关键词
变流器 /
电压跌落 /
暂态稳定性 /
锁相环 /
直流电压控制
Key words
converter /
voltage dips /
transient stability /
PLL /
DC-link voltage control
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基金
国家重点研发计划（2021YFC3100304）; 2024年江苏省研究生科研创新计划（KYCX24_2746）
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