一种二极管无源钳位的单相无变压器型光伏并网逆变拓扑研究  

A Single-phase Diode Clamped Transformerless PV Grid-connected Inverter

作　　者：王金华[1] 顾云杰[1] 胡斯登[1] 李武华[1] 何湘宁[1] 曹丰文[2] 

机构地区：[1]浙江大学电气工程学院,浙江省杭州市310027 [2]苏州市职业大学电子信息工程系,江苏省苏州市215104

出　　处：《中国电机工程学报》2015年第6期1455-1462,共8页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51277195;51377112)~~

摘　　要：提出一种基于二极管无源钳位思想的单相无变压器型光伏并网逆变器拓扑。与H5等传统电路相比,本拓扑具有更好的对地漏电流抑制能力。目前主流的单相无变压器型逆变电路普遍采用直流或交流解耦技术,阻断共模电流的流通路径。但是,功率开关上的寄生电容可能与共模电抗形成谐振回路,使得共模电流无法彻底消除。以H5拓扑为例,定量分析功率器件寄生电容影响共模电流的机理。针对这一问题,引入无源二极管钳位电路,使得共模电压被母线电容中点钳位,从而抑制了功率器件寄生电容引起的共模电压振荡,更有效地消除对地漏电流。在理论和仿真分析的基础上,通过搭建2 k W实验平台验证所提拓扑的性能。结果表明,改进拓扑相对于原拓扑而言,能更好地抑制对地漏电流,提高了无变压器型光伏并网系统的安全裕度。A single-phase transformerless grid-connected photovoltaic （PV） inverter topology was proposed based on diode clamped method. The proposed circuit provides an effective improvement in common-mode current rejection capability, compared with state-of-the-art dc/ac decoupled solutions such as the H5 topology. In the proposed method, an extra voltage clamped path is inserted in an ac-decoupled transformerless inverter through two passive diodes. As a result, the common-mode voltage is clamped by the dc capacitor to eliminate the possible high-frequency common-mode oscillations caused by power device parasitic capacitors, which is the major cause of leakage current in dc/ac decoupled transformerless topologies. The proposed passive clamped technique features cost effective solution with no additional active switches, in comparison with the active clamping counterpart. The performance of the proposed topology has been verified by simulation and experiment with a 2kW prototype.

关 键 词：并网逆变器 漏电流 共模电压 寄生电容 二极管无源钳位 

分 类 号：TM46[电气工程—电器]