中文摘要：

为提高单相光伏并网发电系统的功率因素和输出电压电能质量,降低逆变器单位功率的成本和谐波含量,提高系统的灵活性,提出了一种NPC三电平单相光伏并网逆变器。分析了NPC型三电平的工作原理,研究了NPC型三电平直流侧中点电位不平衡问题,采用空间矢量控制的SVPWM方法对逆变器进行控制。基于MATLAB/SIMULINK仿真环境,建立了NPC三电平SVPWM控制的单相光伏并网发电系统,仿真结果验证了逆变器及控制策略的有效性。

英文摘要：

In order to enhance the power factor and output voltage quality of electric energy, reduce the cost of unit power and harmonic content, a NPC three-level converter was introduced to improve the flexibility of in single phase grid-connected photovoltaic generation system. The working principle of NPC three-level converter was analyzed and the neutral point unbalance problem of DC side was researched. About the control method of converter, the SVPWM control strategy was selected. The single phase grid-connected photovoltaic generation system with NPC three-level converter controlled by SVPWM was established under MATLAB/SIMULINK. The simulation results verify the effectiveness of NPC three-level converter and control strategy.