双馈风力发电机虚拟同步控制策略研究

双馈感应发电机(doubly fed induction generator,DFIG)可通过虚拟同步控制方法为电网提供电压及频率支撑,优化机组并网特性。传统的虚拟同步控制技术以模拟同步发电机机电动态特性为主要目标,未对电磁暂态的DFIG控制进行深入分析。当电网发生不对称故障时,分析虚拟同步控制DFIG的故障特性,发现传统控制方法无法抑制电磁转矩振荡与DFIG故障电流。因此,基于电网不对称故障,本文提出DFIG电压补偿虚拟同步控制方法,通过对转子电压故障分量进行补偿,提高DFIG转子电压响应速度,减少其反电动势故障分量。通过对传统及电压补偿虚拟同步控制方法控制效果的仿真对比可知,电压补偿虚拟同步控制方法可对电磁转矩的持续振荡及暂态冲击进行有效抑制,明显降低了DFIG转子的故障电流,提高了DFIG不对称故障穿越能力。

Research on Virtual Synchronization Control Strategy of Doubly Fed Wind Turbine

Doubly fed induction generator(DFIG)can provide voltage and frequency support for power grid through virtual synchronous control method to optimize grid connection characteristics.The traditional virtual synchronous control aims at simulating the electromechanical dynamic characteristics of synchronous generator,and has not studied the DFIG control of electromagnetic transient.Through the analysis of DFIG fault characteristics of virtual synchronous control in power grid asymmetric fault,it can be seen that the traditional control method can’t suppress the electromagnetic torque oscillation and DFIG fault current.Therefore,based on the asymmetric fault of power grid,the DFIG voltage compensation virtual synchronous control method is proposed in this article.By compensating the rotor voltage fault component,the DFIG rotor voltage response speed is optimized and the rotor back EMF fault component is reduced.Through the simulation and analysis of the control effect of traditional and voltage compensated virtual synchronous control methods,it can be seen that the voltage compensation virtual synchronous control method can effectively suppress the continuous oscillation and transient impact of electromagnetic torque,significantly reduce the fault current of DFIG rotor,and improve the asymmetric fault ride-through capability of DFIG.