基于DZSI光伏发电系统的SVPWAM策略研究

Research on SVPWAM Strategy of Photovoltaic Generation System Based on DZSI

Z源逆变器已开始应用于分布式光伏发电系统中,但传统的Z源逆变器存在升压能力有限、输入电流不连续和启动冲击等问题。采用一种新型的二极管辅助延展型Z源逆变器结构,它能够有效解决传统Z源逆变器的不足。同时,提出了一种基于Z源拓扑的新型调制策略?空间矢量脉冲宽度幅值调制(SVPWAM)策略,它通过消除每个扇区的零矢量,且在每个扇区仅在具有开关动作的单相桥臂插入直通零矢量,从而能够大大降低开关频率。软件仿真和实验结果都表明该调制策略相比于SVPWM调制,它能够更有效地降低逆变器开关损耗和谐波含量,并提高电压利用率。

Z source inverter （ZSI） has been applied in the distributed photovoltaic power generation system, but the tra- ditional Z source inverter has problems of the limited boost voltage capacity, the discontinuous input current, and the impact of starting. Consequently, we adopted a new topology----extension-type diode ZSI （DZSI） to solve the problems of traditional Z source inverter. At the same time, we proposed a new modulation strategy--space vector pulse width ampli- tude modulation （SVPWAM） based on Z source topology, which could reduce the switching frequency by eliminating the zero vector of each sector, and could insert the straight through zero vector into a single phase bridge-arm with switching operation in each sector. The software simulation and experimental results show that the modulation strategy is more ef- fective than the SVPWM modulation, it can effectively reduce the inverter switching losses and the output voltage harmonics, and improve the voltage utilization ratio.