虚拟同步发电机技术在风力发电系统中的应用与展望

随着风电并网容量的不断提升,大量通过电力电子装置并网的风力发电机组使得现有电力系统的转动惯量缺失,造成系统频率稳定性下降等问题愈加严重。虚拟同步发电机技术可通过模拟传统同步发电机的运行特性,提高风机的并网等效惯量和阻尼系数及电网的风能渗透率。首先,论述了近年来虚拟同步发电机技术在风力发电系统中的研究进展,探讨了风能最大功率点跟踪(MPPT)与频率支撑的协调控制,并揭示了实际转子与虚拟同步转子的能量平衡关系。然后,分析了系统参数设计及其对稳定性的影响,并以主流的全功率型风机和双馈型风机为例,介绍了具体控制方法及其未来在大规模风电场聚合等值研究中的应用前景。最后,总结了当前存在的关键技术问题及可行的解决思路。

Application and Prospect of Virtual Synchronous Generator in Wind Power Generation System

With the increasing penetration of wind energy and due to the large-scale utilization of wind turbines, the present power grid is developing into a system with the loss of rotational inertia, thus it brings about various stability problems. However, as the virtual synchronous generator(VSG)technology can mimic the characteristics of the conventional synchronous generator, the equivalent inertia and damping coefficient of wind turbines and the penetration rate of wind energy in the grid are improved. Firstly, the research prospect of VSG technologies which applied in the field of wind turbine control are introduced. Then, the coordinated control of maximum power point tracking(MPPT)and frequency support is discussed, as well as the energy balance between the actual turbine shaft and virtual shaft is revealed. Also, the designs and stability analysis of key parameters of VSG controlled wind turbines are elaborated. The specific applications in wind turbines are illustrated via the simulations on a permanent magnetic synchronous generator(PMSG)-based wind turbine and a doubly-fed induction generator(DFIG)-based wind turbine. Moreover, the feasibility and prospect of the VSG controlled wind turbines in the area of large wind farm aggregation and specific control methods are addressed. Finally, some remaining difficulties and perspective solutions are also demonstrated.