逆变器并联系统中死区的环流效应  

Dead Time Effect in the Parallel Inverters

作　　者：张宇[1] 陈息坤[1] 康勇[1] 陈坚[1] 

机构地区：[1]华中科技大学,湖北武汉430074

出　　处：《电力电子技术》2005年第5期99-100,共2页Power Electronics

基　　金：国家自然科学基金资助项目(50237020)~~

摘　　要：本文通过研究逆变器开关管死区引起的环流发现,在大功率逆变器中,死区的分散性会引起较严重的环流,且环流会随负载的大小及功率因数的变化而变化。由于大功率逆变器中死区通常较大,当用硬件实现死区时会产生很大的分散性,而大功率逆变器的滤波电感及并机电抗又比较小,这使得因逆变器之间的死区差异引起的环流中含有大量的低次谐波,难以通过均流调节器予以消除。本文分析了逆变器并联系统中由死区的分散性引起环流的机理,并基于20kVA并机系统进行了仿真和实验。结果表明,2μs的死区差异可引起30A的环流峰值,这给并联系统带来了很多不良后果。因此,大功率逆变器并联系统中应当尽量避免死区差异的出现。This paper analyzes the circulation currents caused by dead times,which were significant in high power inverters and varied with the quantity and power factor of the load.Because the dead times in high power inverters are always large,when it realized by the hardware,the discrepancy of dead times are also large.On the other hand,the filter inductances and output impedances are normally small in high power inverters,these make the discrepancy of dead times result in large circulating currents. The circulating currents caused by the discrepancy of the dead times include plenty low order harmonics and can hardly be eliminated by the load share regulators.This paper analyzes the mechanism of the dead time effecting on circulation currents.The simulation and experiment based on 20kVA inverters indicated that 2μs difference in dead times will cause 30A circulation currents in magnitude and lead to bad aftermath.So the the discrepancy of dead times in high power inverters should be avoided.

关 键 词：逆变器 并联 环流/死区 

分 类 号：TM711[电气工程—电力系统及自动化]