多电平并网逆变器拓扑结构综述

Survey of the topological structure of multilevel grid inverter

为了找出最佳的多电平并网逆变器拓扑结构,比较传统3类基本多电平逆变器的优缺点,并重点阐述了几种新型拓扑结构,按照前人提出来的基本单元将它们分类。同时,总结了多电平并网逆变器拓扑优化方法以及研究趋向。最终提出了由最佳的2个基本单元构成的混合T型逆变器拓扑结构,并在MATLAB/SIMULINK上进行仿真。仿真结果表明:本文提出的结构相比嵌位二极管型三电平电路(目前最广泛使用的拓扑结构)具有优越性;此结构充分利用IGBT和MOSFET各自的优势,减小了谐波含量,降低了变换器的功率损耗并提高了系统的变换效率;通过对比不同新型拓扑结构可知,新提出的多电平逆变器拓扑都是在基本构成单元的基础上增加了辅助/嵌位电路,用混合开关或者用不对称结构来优化逆变器性能。

To find the best multilevel grid-connected inverter topology structure, this paper compared the advantages and disad-vantages of the three traditional kinds of basic multilevel inverters ^ and the structures of several novel types of topologies were de-scribed emphatically, and were classified according to the basic units which were proposed by predecessors. At the same time, the multilevel grid inverter topology optimization methods and the research trends were summarized. Eventually, the hybrid T-type inverter topology structure, composed of the two best basic units was proposed. And the simulation was based on the MATLAB/ SIMULINK platform. Results show that it？s superiority over the clamping diode type three level circuit （the most widely used to-pology nowadays）. This structure make full use of the advantages of the two devices, reduce the harmonic content and the power loss of the converter, and improve the conversion efficiency of the system. By comparing with the different new topologies, it is known that novel types of multilevel inverter topology optimize the performances of the inverter by adding auxiliary/clamping cir-cuit, or using hybrid switch or asymmetric structure.