基于谐波阻尼的双馈感应发电机定子谐波电流抑制改进策略

通过建立电网电压谐波下双馈感应发电机(DFIG)的数学模型,分析了电网电压谐波对DFIG性能的影响,以抑制定子电流5次和7次谐波为目标,在转子电流内环采用比例—积分—谐振(PIR)调节器的基础上,引入定子谐波电流闭环控制策略,避免了常规谐波抑制策略转子电流指令计算对发电机参数的依赖。随着定子谐波电流环R调节器增益系数的增大,对定子电流中的谐波抑制越明显,但是抗扰动能力下降,通过引入谐波阻尼控制,在最大限度抑制定子电流谐波的基础上增强了系统的抗扰动能力,提高了系统的鲁棒性,加快了系统的动态响应。并从稳态特性和动态特性角度分析了参数变化对系统的影响。最后通过仿真和实验验证了所提控制策略的有效性。

Harmonic Damping Based Improvement Strategy for Suppressing Stator Harmonic Current of Doubly-fed Induction Generator

Based on the mathematical model of doubly-fed induction generator(DFIG)under harmonically distorted grid voltage conditions, the impact of power grid voltage harmonic on DFIG operation performance is analyzed. In order to suppress the 5th and 7th harmonics of stator current, the closed-loop control strategy of stator harmonic current is introduced based on the rotor current loop with proportional-integral-differential(PIR)regulator, avoiding the dependence of rotor current command calculation in conventional harmonic suppression control strategy on generator parameters. With the increasing of R regulator gain coefficient in stator harmonic current loop, the suppression on stator harmonics is more obvious, but it will decrease the anti-power disturbance. By introducing the harmonic damping control, the system anti-disturbance ability is enhanced on the basis of maximum suppressing stator current harmonics. Consequently, the system robustness is improved, and the system dynamic response is accelerated. Considering dynamic and steady state characteristics, the influence of parameters change on the system is analyzed. The effectiveness of the proposed control strategy is validated by the experiment and simulation. This work is supported by National Natural Science Foundation of China(No. 51277050)and State Grid Corporation of China(No. NY71-15-037).