基于SVPWM五相三电平H桥逆变器中点电位控制研究

Research on Space Vector PWM of Five-phase Three-level H-bridge Inverter and the Neutral Point Control

针对多相三电平H桥逆变器的电压矢量数量多,难以应用传统的空间矢量PWM算法的问题,提出了一种简化的五相三电平H桥逆变器空间矢量PWM算法。该方法采用相移SPWM思想,将五相三电平H桥逆变器作为两个由单桥臂组成的五相分别予以控制。分析选择合理的工作电压矢量及开关作用顺序,计算了开关周期内的各工作电压矢量的作用时间;不同开关状态下,针对中点电位分析的基础上,提出利用冗余矢量对中点电位进行控制,实现了电容电压的平衡。

As for the five-phase three-level H-Bridge inverter, the number of its output voltage vectors is so high that it＇s hard to apply the traditional SVPWM algorithm method. In this paper, a simplified SVPWM algorithm suitable to the five-phase three-level H-Bridge inverter is proposed. Based on the Phase-shift SPWM method, the five-phase three-level H-Bridge inverter can be taken as two single five-phases, and each can be controlled alone. The work voltage vectors and the switching sequence is chosen rationally, and then the actuation duration of each vector in each control cycle is figured out. The neutral point voltage unbalancing problem which exists in the diode-clamped, three-level inverter is also analyzed, and then the control method by choosing the positive and negative small vectors alternatively, which is used to inhibit the neutral point fluctuation, is proposed.