增强变流器对电网阻抗适应性的陷波前馈控制  

Notch Filter Based Grid-voltage Feedforward Control for Enhancing Grid-connected Converter′s Adaptive Capacity to Grid Impedance Variation

作　　者：黄现莲 冯向东[2] HUANG Xianlian;FENG Xiangdong(School of Electrical and Information Engineering,North Minzu University,Yinchuan 750021,Ningxia,China;Department of Mechanical and Electrical Engineering,Ningxia Business Vocational College,Yinchuan 750021,Ningxia,China)

机构地区：[1]北方民族大学电气信息工程学院,宁夏银川750021 [2]宁夏工商职业技术学院机电工程系,宁夏银川750021

出　　处：《电气传动》2017年第10期24-28,共5页Electric Drive

基　　金：北方民族大学校级科研一般项目(2017DX010)

摘　　要：由于电网电压前馈可减小启动电流对并网变流器的冲击,因此被广泛应用在并网变流器控制中。然而,在弱电网条件下电网电压前馈会导致系统稳定性下降,甚至出现不稳定。首先建立了弱电网条件下并网变流器的数学模型,并基于根轨迹和最小增益定理对弱电网条件下采用传统电网电压完全前馈时系统的鲁棒稳定性进行了分析。针对采用传统完全电网电压前馈时系统鲁棒稳定性较低的问题,提出了基于陷波器的改进前馈控制策略。通过引入陷波器对系统开环穿越频率附近的前馈电压进行幅值衰减,实现增益稳定,从而提高并网逆变器对电网阻抗的鲁棒稳定性。最后,搭建了并网变流器实验样机,实验结果证明了理论分析的正确性和所提控制策略的有效性。The grid-voltage feedforward control is widely used in the grid-connected converter control,becauseit can reduce the shock caused by the startup inrush current.However,the voltage feedforward will cause thereduction of the system′s stability,and even the instability.The mathematical model of the grid-connected converterin the weak grid was established,and the robust stability of the converter with the traditional feedforward control inthe weak grid was analyzed using the root locus and small gain theory.Owing to the poor robust stability of thetraditional full-feedforward control,the notch filter based feedforward control method was proposed.To realize thegain stabilization,the notch filter was introduced to tailor the magnitude of the voltage around the cross-overfrequency.Therefore,the converter′s robust stability against the grid impedance variation could be improved.Finally,the prototype of the grid-connected converter was built,the experimental results confirm the validity of the analysisand the proposed strategy.

关 键 词：并网变流器 弱电网 电网电压前馈控制 鲁棒稳定性 陷波器 

分 类 号：TM461[电气工程—电器]