一种新型NPC非隔离光伏并网逆变器

A Novel NPC Transformerless PV Grid-Connected Inverter

三电平MPC非隔离并网逆变器具有开关损耗小、共模特性好、输出失真小等优点。提出了一种高可靠性的三电平半桥MPC逆变器,该拓扑只需要4个开关管和两个二极管就具有恒定的共模电压。更重要的是,与传统的半桥NPC逆变器相比,本文提出的拓扑结构可以在不增加死区时间的情况下避免桥臂直通问题。此外,与大多数NPC半桥逆变器和双Buck型半桥NPC逆变器相比,该拓扑具有更低的导通损耗。分析了该拓扑结构的共模模型和工作原理,证明了其优越性。最后,搭建仿真模型和实验平台验证了理论结果。

The three-level NPC transformerless grid-connected inverter has the advantages of low switching loss,good common-mode characteristic and low output distortion.A three-level half-bridge NPC inverter with high reliability is proposed in this paper.The topology only needs four switches and two diodes,which can gets a constant common-mode voltage.More importantly,compared with the traditional half-bridge NPC inverter,the proposed topology can avoid the bridge arm through problem without increasing the dead time.Moreover,compared with most NPC half-bridge inverters and dual buck half-bridge NPC inverters,the topology has lower conduction losses.The common mode model and working principle of the topology are analyzed to prove its superiority.Finally,the simulation model and experimental platform are built to verify the theoretical results.