中文摘要：

二极管钳位型（NPC）多电平逆变器能将直流电源高效转化成谐波良好的交流电能,并输入电网设备中。但是,采用传统空间矢量脉宽调制（SVPWM）算法存在扇区判断复杂,系统响应慢等问题,尤其是在高电平数的逆变器中。基于降阶原理的NPC多电平逆变器能将高电平逆变策略降阶成低电平逆变器的简单调制,避开SVPWM策略在高电平逆变器中计算复杂、不利于软件实现等缺陷。Matlab仿真平台在三相离网/并网光伏发电系统上搭建NPC三电平逆变器,对此策略进行实验验证。

英文摘要：

The DC power is transefered into the AC power with better harmonic by the NPC multilevel inverter, witch could be inputted to the grid equipments. However, the complex sections＇ judgement, the slow system response and other problems are existed in the traditional SVPWM, especially, in the higher multilevel inverters. The NPC multilevel inverter based on the reduce order principle was proposed, that could reduce the higher multilevel inverter strategy to the lower simple one. Therefore, the disadvantages of traditional SVPWM strategy was avoided, such as the complex calculation,hard software implementation, etc. What＇s more, it was proved in three-phase off-grid/photovoltaic grid-connected generation system with NPC three level inverter by Matlab experimental platform.