基于改进型零序环流抑制方法的T型三电平并联并网系统  

An Improved Zero-Sequence Circulating Current Suppression Based Method in Parallel Three-Level T-Type Grid-Connected Inverters

作　　者：邢相洋[1] 陈阿莲[1] 张子成[1] 潘羿威 杜春水[1] 张承慧[1] 

机构地区：[1]山东大学控制科学与工程学院,山东省济南市250061

出　　处：《中国电机工程学报》2017年第14期4165-4174,共10页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51377101);国家重大国际(地区)合作研究基金项目(61320106011);国家重大仪器研制专项项目(61527809)~~

摘　　要：模块化的并联T型三电平逆变器能够增加系统功率等级和效率,但共直流母线无隔离拓扑可能引起零序环流问题。前期研究已经证明通过调整零序分量作用时间能够抑制零序环流。然而该方法没有考虑输出电流不同引起的扰动,输出电流波形质量变差。该文分析环流模型的基础上,设计了比例–积分和前馈控制器,零轴环流扰动控制通过对小矢量调节来实现的。并采用双采样法来提高零轴零序电流控制带宽。零序环流能够在输出电流不同工况下得到很好地抑制,实验结果验证了所提算法的有效性。Module parallel three-level T-type inverters （3LT^2Is） can increase power rating and efficiency of systems. However, the topology of transformerless inverters with common dc-link would cause the zero-sequence circulating current （ZSCC） problem. Previous papers have proven that the ZSCC can be suppressed by adjusting the time of the zero-sequence component. However, the performance would be deteriorated without considering the disturbance caused by differences in currents. An averaged model of ZSCC was analyzed in detailed. A small vector feed-forward control method with the PI controller was proposed to reject disturbance in zero-axis current systems. Moreover, a double sampling method was employed to expand the bandwidth of the zero-axis current system. Therefore, the ZSCC can be suppressed satisfactorily when output currents are different by applying the proposed scheme. The effectiveness of the proposed method is verified by the experimental results.

关 键 词：T型三电平逆变器 小矢量前馈控制 零序环流 双采样法 

分 类 号：TM464[电气工程—电器]