基于虚拟同步发电机的频率谐振抑制策略

Frequency Resonance Suppression Strategy Based on Virtual Synchronous Generator

虚拟同步发电机(Virtual Synchronous Generator)技术应用于新能源并网,其惯量和阻尼特性可灵活调节,提高了电力系统可控性、安全性及稳定性。大多数对VSG系统的研究都忽略了电磁磁链的动态过程引发的同步频率谐振现象,该现象在控制参数设计不合理时会导致系统稳定性下降,针对这一问题文中提出了选择VSG最优参数的约束条件。通过分析VSG的同步频率谐振产生机理推导出VSG系统的全频段动态功角,在此基础上推算出维持VSG系统稳定的约束条件,从而引入虚拟惯量与阻尼系数的最佳比值以及虚拟阻抗,消除了同步频率谐振,提高了虚拟同步发电机的稳定性。使用Matlab/Simulink软件进行仿真,验证了所提的控制策略具有有效性和可行性。

Virtual Synchronous generator technology is applied to the grid-connected new energy,its inertia and damping characteristics can be flexibly adjusted,which improves the controllability,safety and stability of the power system.Most researches on VSG systems had ignored the phenomenon of synchronous frequency resonance caused by the dynamic process of electromagnetic flux.This phenomenon will cause the stability of the system to decrease when the control parameter design is unreasonable.Aiming at this problem,the constraint conditions for selecting the optimal parameters of the VSG were proposed.By analyzing the mechanism of VSG's synchronous frequency resonance generation,the full-frequency dynamic power angle of the VSG system was derived,and on this basis,the constraint conditions for maintaining the stability of the VSG system were calculated,thereby introducing the best ratio of virtual inertia to damping coefficient and virtual impedance,eliminating the synchronous frequency resonance and improving the stability of the virtual synchronous generator.The simulation using Matlab/Simulink software verifies the validity and feasibility of the proposed control strategy.