新型拓扑滤波器的双馈风电网侧变流器阻尼策略

Damping Strategy of Grid-side Converter With New Topology Filter in Doubly-fed Wind Power System

对基于LCL滤波的双馈风力发电机组网侧变流器谐振阻尼策略进行研究。首先对电容串联和并联电阻的无源阻尼方式在滤除高次谐波和阻尼电阻功率损耗方面进行比较研究。其次,为降低无源阻尼方式中电阻的功率损耗,提出一种新型的有源阻尼策略。在对网侧变流器采取电网电流反馈闭环控制的基础上,利用电容电流和比例环节对电网电流闭环极点进行配置,以增大控制系统的阻尼,抑制谐振发生;同时对比例环节参数对电流闭环的影响进行分析,并给出参数的选择原则。最后,通过搭建基于LCL滤波器的双馈风力发电系统网侧变流器仿真模型和实验系统,对理论进行验证。仿真和实验结果都证明了理论的正确性。

This paper investigated of damping of resonance oscillations for grid-side converter with LCL filter for doubly-fed wind power system. Firstly, capacitors parallel with or in series with resistors as reactive damping were analyzed in this paper, and the effect to filtering high order harmonics and power losses for different reactive damping strategies were compared. Secondly, in order to reduce power losses of damping resistors this paper proposed a novel active damping control strategy. The grid-side currents converter with LCL filter were measured and controlled, and capacitor currents were used to regulate converter-side voltage to damping resonance of LCL filter. The proportional links were used to change amplitude of capacitor currents to meet system requirement. Finally, Simulating model and experimental system were set up, and the analyses of theories in the paper are verified by stimulated and experimental results.