一种高效率H6结构不隔离单相光伏并网逆变器

提出一种新颖的高效率六开关逆变器(H6)拓扑,解决了无变压器单相光伏并网逆变器漏电流问题。该拓扑将两个单向续流单元嵌在全桥逆变器桥臂中点之间,以获得续流通道,并在续流阶段将太阳能电池板和电网分离。该拓扑续流回路不经过性能较差的体二极管,有利于获得更高效率;同时,无需直流旁路结构中的分裂电容。详细介绍该拓扑的工作原理、脉宽调制(pulse width modulation,PWM)驱动逻辑、并网控制方法以及关键电路设计。仿真与实验验证了该拓扑具有低共模电压、高质量的并网波形和高效率特征。

A High Efficiency Non-isolated Single-phase Photovoltaic Grid-connected Inverter With H6-type Configuration

This paper proposed a novel,high efficiency,transformerless single phase photovoltaic grid-connected inverter with six active switches that alleviate leakage current issue.This topology embeds two unidirectional freewheel units into the midpoint of a full bridge inverter,which provide novel freewheel paths and separate battery cells from a grid during freewheeling time.Body diodes with poor performances of active switches are not used so it achieves higher efficiency.Meanwhile,there is no need of split capacitors like that in topologies with dc bypass structure.The detailed power stage operating principles,PWM scheme,grid-connected control strategy and key components design are described.Simulation and experiment results verify that this topology features low common mode voltage,high power quality and high efficiency.