中文摘要：

针对光伏发电系统对非隔离逆变电路的需求,提出构成一类中点钳位非隔离全桥光伏并网逆变器的2种基本开关单元：中点钳位正单元（positive-neutral point clamped cell,P-NPCC）和中点钳位负单元（negative-neutral point clampedc ell,N-NPCC）。提出由2种基本单元构造中点钳位全桥逆变器拓扑的生成机理和推演方法,按照该方法可以得到现有的中点钳位非隔离全桥光伏并网逆变器拓扑,如oH5、FB-DCBP以及一族新的中点钳位非隔离全桥并网逆变器拓扑。以所提PN-NPC拓扑为例详细分析了其工作原理,并实验比较了PN-NPC和Heric拓扑的变换效率和共模特性。所提拓扑的共模电压为恒定值,且其变换效率和共模特性均优于Heric拓扑。

英文摘要：

Two types of basic switching cells,positive-neutral point clamped cell and negative-neutral point clamped cell,and a method to build neutral point clamped（NPC） full bridge photovoltaic（PV） grid-connected inverters with these two basic cells are proposed to meet the demand for non-isolated inverter topology applied in PV generation system.A family of novel NPC non-isolated full bridge PV grid-connected inverters,besides existing topologies such as oH5 and FB-DCBP,is derived.Operation modes of the PN-NPC topology are analyzed as an example in detail.Finally,both of the efficiency and common-mode performance of the proposed PN-NPC and Heric topologies were compared with experimental results.And the comparison results show that the proposed PN-NPC topology features better efficiency and common-mode performance than that of the Heric topology.