线电压级联型quasi-Z源逆变器研究

Research on Cascaded Three-phase quasi-Z Source Inverter

文章提出一种线电压级联型quasi-Z源逆变器(LVC-qZSI),其以quasi-Z源网络、三相逆变器为单模块单元,通过线电压级联方式构成级联型多电平逆变器。文中将逆变器运用于并网发电系统中,建立其数学模型,分析其运行机理特性;并提出了一种改进型电压电流双闭环控制系统,搭建了仿真模型,验证其拓扑结构和控制算法的有效性。改进后的直流侧网络具备升压功能,各模块直流侧输入电压仅需180 V即可实现380 V无变压器直接并网,降低了成本;其拓扑开关频率较低,减少了开关损耗,且并网电流谐波含量仅为1.84%。

It presented a LVC-qZSI（line voltage cascaded quasi-Z source inverter） which uses a multiplexed inverter topology cascaded by line voltage and its module unit is composesd by two modules：quasi-Z source network and three-phase inverter.Applying the proposed inverter to grid-connection generation system through an analysis of the function feature of established mathematical model,an improved dual-loop control system was proposed.To demonstrate the effectiveness of the topology and control system,a simulation model was built.Voltage boost is added in the improved DC side network,where 180 V input voltage of each module can realize 380 V direct grid-connection without transformer.Costs and switch frequency are decreased,and harmonic content of grid current is merely 1.84%.