单相无变压器型光伏并网逆变器的拓扑结构及共模电流分析

Topology of Single-phase Transformerless Type Photovoltaic Grid-connected Inverter and Analysis of Its Common-mode Current

针对单相无变压器型光伏并网逆变器拓扑结构存在共模电流的问题,介绍了几种能有效抑制共模电流的拓扑结构,即双极性调制的单相全桥式拓扑结构、带交流旁路的全桥式拓扑结构、H5拓扑结构及NPC拓扑结构;详细分析了这几种拓扑结构抑制共模电流的原理,并从开关损耗及系统效率两个方面对这几种拓扑结构进行了比较,指出H5拓扑结构性能最优。

In view of the problem of common-mode current existed in topology of single-phase transformerless type photovoltaic grid-connected inverter,several topologies were introduced which can restrain common-mode current effectively,namely single-phase full-bridge topology with double-polarity modulation,full-bridge topology with AC bypass,H_（5） topology and NPC topology.Principle of restraining common-mode current of these topologies were analyzed in details,and these topologies were compared in terms of switching loss and system efficiency. Finally,it was pointed out that H_（5） topology has best performance.