摘要
共模电压抑制是非隔离型光伏并网逆变器的一个关键问题,但是传统零共模电压调制方法无法同时兼顾消除共模电压和减小输出电流谐波2个方面的性能。该文利用逆变器之间的交互作用,分析并联三电平逆变器的五电平电压输出能力,提出将整个并联系统作为一个五电平设备进行调制的思路。基于该五电平系统中共模电压为零的基本矢量,该文提出一种适用于并联三电平逆变器的新型零共模电压调制方法,推导出详细的调制实现过程,并针对开关序列特性提出相应的中点电压平衡策略。仿真和实验表明,该方法在确保共模电压为零的同时,还能大幅减小并联输出电流的谐波畸变,可有效满足非隔离型并联光伏逆变器对消除共模电压和减小电流谐波的要求。
The suppression of common mode voltage(CMV) is critical for the non-isolated grid connected PV inverter. However, conventional zero CMV modulation method cannot guarantee CMV elimination and output current quality simultaneously. Based on the interaction between the parallel three-level inverters, the five-level voltage output capability of the parallel system is analyzed, and a novel five-level zero CMV modulation scheme utilizing only the basic vectors corresponding to zero CMV was proposed, including the detailed implementation of the modulation method. Furthermore, a neutral point voltage balancing strategy was also developed based on its specific switching sequences. Simulation and experimental results verify that the proposed method is effective to eliminate the CMV and dramatically reduce the output current harmonics compared with conventional method.
作者
李伟伟
张学广
庄嫣媛
徐殿国
LI Weiwei;ZHANG Xueguang;ZHUANG Yanyuan;XU Dianguo(Department of Electrical Engineering,Harbin Institute of Technology,Harbin 150001,Heilongjiang Province,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2020年第19期6308-6319,共12页
Proceedings of the CSEE
基金
国家重点研发计划项目(2018YFB0904000)
国家自然科学基金项目(51977046,51720105008)。
关键词
并联运行
零共模电压调制
五电平空间矢量
三电平逆变器
parallel operation
zero common mode voltage modulation
five-level space vector
three-level inverter
