不平衡及谐波电网条件下双馈风电变流器的改进控制研究

Improved control of DFIG based wind power converters during unbalanced and distorted grid voltage conditions

针对双馈风电机组在电网电压不平衡及谐波畸变条件下的故障穿越问题,分析了此类电网故障对机组运行性能的影响,提出了一种双馈机组转子侧、网侧变流器的协同控制方案。通过改进转子侧、网侧变流器的矢量控制算法,抑制了双馈感应电机的电磁转矩波动,降低了机组输出总有功功率的波动,获得了对称、正弦的机组输出电流。仿真结果表明,所述控制方案能够显著改善双馈风电机组在此类电网故障条件下的运行性能,从而提高机组的故障穿越运行能力。

Aiming at the problem of the fault ride-through（ FRT） capability of doubly fed induction generator（ DFIG） based wind turbines during unbalanced and distorted grid voltage condition,the influence of the faulty grid to the turbines was analyzed. And then a coordinated control method for both the grid-and rotor-side converters（ GSC and RSC） was presented. By improving the vector control algorithm of both the GSC and RSC,the DFIG＇s electromagnetic torque oscillations were suppressed and the total power pulsations were reduced. In addition,symmetry and sinusoidal output currents of the turbines could also be obtained. The simulated results indicate that the proposed control can obviously improve the operation performance of DFIG based wind generation systems under such adverse grid conditions and thus enhance the turbines＇ fault ride-through capability.