非线性不平衡负载下四桥臂逆变器的控制策略  

Control strategy of four-leg inverter with nonlinear and unbalanced loads

作　　者：张蒙蒙 徐永海[1] 关金萍 Zhang Mengmeng;Xu Yonghai;Guan Jinping(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Source,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学新能源电力系统国家重点实验室

出　　处：《电测与仪表》2019年第12期116-122,共7页Electrical Measurement & Instrumentation

基　　金：北京市自然科学基金资助项目(3172036)

摘　　要：电力电子变压器输出级逆变器与微电网中的离网逆变器输出特性直接受负载影响,交流负荷中含有大量的非线性与不平衡混合负载,会引起三相逆变器输出电压谐波畸变及不平衡,为了解决这个问题,提出了一种适用于三相四桥臂的电压不平衡和谐波抑制的混合控制策略。首先,基于四桥臂逆变器的数学模型,阐明了桥臂间的耦合关系;然后,详细分析了实现交流信号无差跟踪与抑制谐波对控制器工作性能的需求,并通过对伯德图的幅频特性分析,说明所提控制方法及参数选择的合理性。最后在αβ0坐标系下对非线性、不平衡混合负载接入下的逆变器进行仿真,验证了所提出控制策略及控制参数选择的正确性。The output characteristics of power electronic transformer output stage inverter and off-grid inverter in micro-grid are directly affected by loads. AC loads usually contain a large number of nonlinear and unbalanced mixed loads, which will cause harmonic distortion and imbalance of three-phase inverter output voltage. Aiming at solving those problems, a hybrid control strategy of three-phase four-leg inverter is proposed for unbalanced voltage compensation and harmonic suppression. Firstly, the coupling relationship among the four-leg is clarified, which is based on the mathematical model of the four-leg inverter. Then, the requirements for eliminating AC signal tracking error and suppressing harmonics are analyzed in detail. Meanwhile, the effectiveness of the proposed control method and parameter selection is illustrated by analyzing the amplitude-frequency characteristics of bode diagram. Finally, the correctness and validity of the proposed control strategy and selected control parameters for the inverter with nonlinear and unbalanced mixed load is verified by the simulation results in αβ 0 coordinate.

关 键 词：三相四桥臂逆变器 αβ0坐标系 谐波抑制 不平衡电压补偿 

分 类 号：TM933[电气工程—电力电子与电力传动]