三相电压型PWM变流器交流侧LCL滤波器的有源阻尼策略研究

Research on active damping strategy of LCL filter in three-phase voltage source PWM rectifier

三相电压型PWM变流器是分布式可再生能源发电单元接入传统配电网的主要接口设备。在PWM变流器主电路设计中,采用LCL滤波器替代传统的L型滤波器已经被广泛地接受。针对含LCL滤波器的三相电压型PWM变流器,在系统输入输出模型与传递函数的基础上,提出了一种新型LCL滤波器优化设计方法。与传统L型滤波器相比,该方法具有电感总量小、动态性能好、系统成本低的优点。为了抑制LCL滤波器的固有谐振,在基于同步旋转坐标系的三相电压型PWM变流器控制中,通过在电流环中增加陷波滤波器的方法实现了LCL滤波器的有源阻尼。最后通过仿真和实验对所提出方法的正确性和有效性进行了证明。

Three-phase voltage-mode PWM converter is the main interface device between distributed renewable energy generation unit and traditional distribution network. In the main circuit design of PWM converter, using LCL filter to replace the traditional L filter has been widely accepted. In view of three-phase voltage-mode PWM converter with LCL filter, on the basis of input and output model and system transfer function, a novel LCL filter optimal design method is proposed. Comparing with the traditional L filter, the novel method has advantages on smaller total inductance, better dynamic performance and lower system cost. In order to prevent the inherent resonance of LCL filter, it increases a notch filter in current loop to achieve active damping of LCL filter in synchronous rotating coordinate system. The experimental results verify the correctness and effectiveness of the proposed method.