光伏发电三相三电平并网逆变器新型调制算法

New Modulation Algorithms of Three-phase Three-level Grid-connected Inverter for Photovoltaic Power

在NPC三电平逆变器中点电位控制中,传统的七段式空间矢量脉宽调制(SVPWM)策略在一个周期内用到小矢量的两个开关状态,通过调节矢量作用时间平衡中点电位。而本文在其基础上,提出一种五段式开关序列,在中点电位控制上采取方式0、方式1的两种方式进行切换,而且还能实现大电流不开关,这相对于传统的七段式更能减少开关次数,降低开关损耗,最后通过Matlab仿真实验验证了所提调制策略的可行性。

In NPC three-level inverter,the traditional space vector pulse width modulation(SVPWM)strategy is to use two switching states of small vectors in one cycle and balance the midpoint potential by adjusting the action time.On the basis of this,a five-stage switch sequence is implemented in this paper.Two modes of mode 0 and mode 1 are adopted for the midpoint potential problem,and the high-current non-switching is realized at the same time.Compared with the traditional seven-stage switch sequence,this method can reduce the number of switches and the switching loss.The feasibility of the proposed modulation strategy is verified by matlab simulation experiment.