文档介绍：四桥臂三相逆变器的控制策略
阮新波严仰光
摘要提出了一种新型的三相四线逆变器,它有四个桥臂,第四个桥臂用来构成中点,从而省去了三相三桥臂逆变器中的中点形成变压器,减小了逆变器的体积和重量。针对这种逆变器,本文提出了一种电流调节器,它根据三相滤波电感电流和给定电流的误差值最大的那相选择逆变器的开关模态。为了消除输出相电压的静态误差,本文讨论了一种基于PI调节器改进的电压调节方案。仿真结果表明,本文的思路是可行的。本文为构造大功率、高效率的三相四线逆变器提供了可靠的理论基础。
关键词:三相逆变器控制策略
The Control Strategy for Three-Phase Inverter with Four Bridge Legs
Ruan Xinbo Yan Yangguang
(Nanjing University of Aeronaut ics & Astronautics 210016 China)
Abstract A novel threephase inverter with four bridge legs i s presented in this inverter eliminates the neutral forming transforme r by adding a bridge leg to form neutral point to provide balanced voltages to a ny kinds of three phase principle of the inverter is analyzed,and a ne w current regulator,which chooses switching modes according to the maximum cur rent error of filter inductance current and the reference current is e modified voltage regulator on the basis of PI regulator is proposed to elimina te output voltage static error under any load conditions.
Keywords:Three-phase Inverters Control strategies
1 引言
三相逆变器一般是采用三个桥臂组成的拓扑结构,为了给不对称负载供电,必须在输出端加入一个中点形成变压器(Neutral Formed Transformer,NFT),如图1所示。中点形成变压器是变比为1的自耦变压器,工作频率为输出交流电的频率,体积和重量很大,而且体积和重量随着负载不对称的程度变化而变化,不对称度越大,NFT的体积重量也就越大。
图1 带NFT的三相逆变器
Three-phase inverter with NFT
为了省去中点形成变压器,减小逆变器的体积和重量,可以在图1所示的逆变器的基础上加入一个桥臂来构成中点,将三相输出的公共点(即中点)接在该桥臂上,从而构成四桥臂三相逆变器,如图2所