【摘要】 二极管箝位式多电平逆变器由于结构简单,输出波形质量高,可以降低器件耐压等级,在高压大功率场合备受关注。但其存在直流测电容电压平衡问题,另外电平数增多时,空间矢量调制算法也变得复杂而难以应用。该文介绍了一种基于60°坐标系的通用SVM快速算法,可迅速得到参考矢量的最近3个空间矢量及各其各自作用时间。通过总结的矢量分布规律,能够快速得出所有冗余矢量而无须查表。另外对矢量切换原则和输出顺序也进行了分析。在其基础上,提出了动态选择冗余矢量和动态选择矢量序列的方法,针对不同功率因数负载下的电容电压平衡进行了研究并得出了其适用范围。针对高功率因数负载时电容电压失衡的原因,该文从一般意义上进行了分析,并针对五电平逆变器提出了具体的解决方法。仿真结果验证了该文算法的正确性和有效性。更多还原

【Abstract】 Diode clamped multi-level inverter (DCMLI) gains more and more attention in fields of high power and voltage due to its simple structure, high quality output wave and ability to decrease the rated voltage of switch devices. But there exists the problem of capacitor voltage unbalance, and when the number of level increases, the space vector modulation (SVM) algorithm becomes more difficult to apply. This paper introduced a universal fast SVM algorithm based on 60° coordinate, which can easily get the three nearest vectors around the reference vector and their dwelling time. All redundant space vectors can be obtained quickly without lookup table through the rule for the distribution of space vector. The switching principle and output sequence of vectors are also analyzed. Based on the fast algorithm, capacitor voltage balance under different power factors is studied by using two methods: selecting redundant vectors dynamically and selecting vector sequence dynamically. Furthermore, this paper analyzes the cause of capacitor voltage unbalance under high power factor load in general sense, and puts forward a practical way to solve this problem for five level DCMLI. Simulation results verify the validity of the algorithm proposed in this paper.更多还原