双馈异步型风机的虚拟同步控制策略

Virtual Synchronous Control Strategy of DFIG-Based Wind Turbines

首先,针对DFIG型风机的转子侧变流器,提出基于转子励磁磁链定向的虚拟同步发电机(VSG)控制。同时,针对DFIG型风机的网侧变流器虚拟同步电动机(VSM)控制,从而使得DFIG型风机的并网接口特性可等效为一台传统同步发电机,在稳态时维持传统风机最大功率跟踪特性,在动态过程中还能向电网提供有效功率支撑,最终实现DFIG风机并网系统的VSG功能。然后,进一步将基于虚拟功率计算的风电机组同期控制应用于DFIG机组,实现DFIG型风机的孤岛/并网过程的无缝切换。最后,通过DFIG型风机并网系统仿真对提出的控制策略的有效性和可行性进行了验证。

Firstly,for the rotor-side converter of the DFIG wind turbine,a virtual synchronous generator(VSG)control based on the orientation of the rotor excitation flux linkage is proposed.At the same time,the virtual synchronous motor(VSM)control for the network converter of DFIG fan makes the parallel interface characteristics of DFIG fan equivalent to a traditional synchronous generator,which maintain the maximum power tracking characteristics of traditional wind turbines in steady state,and provide effective power support to the grid during the dynamic process.The VSG function of the DFIG wind turbine grid-connected system is realized.Then,the synchronization control of wind turbines based on virtual power calculation is applied to DFIG units to realize the seamless switching of the islanding/grid-connection process of DFIG wind turbines.Finally,the effectiveness and feasibility of the proposed control strategy are verified by the simulation of the DFIG wind turbine grid-connected system.