一种新型高效单相非隔离光伏并网逆变器

研究了一种新型高效、高可靠性的单相非隔离光伏并网逆变器,利用相互独立的2只耦合电感隔离并网输出电压的正负半波,逆变桥拓扑为H6对称结构,使网侧电压与光伏组件安全隔离,能彻底去除高频分量,有效抑制共模电流。新型逆变器每只开关管串联一只隔离二极管,解决了传统电压型全桥逆变器存在桥臂直通的短路问题,不需设置"死区"切换时间,改善了交流侧输出波形质量,提高了逆变器效率。经对3 kW实验样机测试和比对分析,验证了逆变器的性能优于传统H4隔离式全桥拓扑。

A Novel Photovoltaic Grid-Connected Inverter of High Efficiency Single-Phase Without Transformer

This paper presents a high-reliability single-phase transformerless grid-connected inverter that utilizes two split ac-coupled inductors operate separately for positive and negative half grid cycles. Inverter topology is H6 symmetric structure and it makes photovoltaic array decoupled from the grid. This reduces the high-frequency common-mode voltage leading to minimized ground loop leakage current. Each switch are connected in series with a diode. This eliminates the shoot-through issue that is encountered by traditional voltage source inverters. Dead time is not required at switching commutation, improving the quality of the output ac-current and increasing the converter efficiency. Through the analysis of 3kW experimental prototype test and comparison, it proves the proposal topology has obvious advantages over H4 transformerless topology.