带续流开关的中点箝位型非隔离光伏逆变器

为了满足非隔离光伏发电系统低漏电流的要求,提出了一种带续流开关的中点箝位型非隔离光伏逆变器。该拓扑在全桥逆变器的交流侧加入了一个续流开关,使得太阳能电池板输出端与电网断开,提高了非隔离光伏逆变器的转换效率。另一方面中点箝位电路的应用使得该拓扑在功率处理阶段和续流阶段的共模电压基本保持不变,降低了漏电流。详细分析了拓扑的工作原理,给出了其控制方法,并通过Saber仿真软件验证了带续流开关的中点箝位型非隔离光伏逆变器良好的共模特性。实验研制了一台300 W的原理样机验证了理论分析的正确性及仿真方案的可行性。

A Neutral Point Clamped Non-isolated PV Inverter with a Freewheeling Switch

In order to meet the requirement of common-mode leakage current in photovoltaic ( PV) generation sys-tems, a neutral point clamped non-isolated PV inverter with a freewheeling switch is proposed .A freewheeling switch is added in AC side of the full bridge inverter in this topology , which will improve the non-isolated PV inverter conver-sion efficiency because the freewheeling switch makes the output of the solar panels off the grid .On the other hand , common-mode voltage remains constant on power processing and freewheeling stage owing to the neutral point clamped circuit.The operational principle of topology is analyzed in detail and its controlling strategy is introduced in this pa -per.It is proved that common-mode performance of the proposed topology was good by Saber simulation software .The effectiveness and feasibility of the proposed topology and strategy have been verified in a prototype rated at 300 W.