摘要
对于三电平逆变器,传统的空间矢量脉宽调制(space vector pulse width modulation,SVPWM)方法需要进行大量的三角函数计算及参考矢量扇区判定,增加了控制器的运算时间,若考虑中点电位平衡的问题,算法复杂度将进一步增加,另外,目前缺乏简单有效的对不同SVPWM策略下逆变器输出波形质量的评价方法。为此,在60°坐标系SVPWM策略基础上,提出一种采用二分法的简化调制策略,该策略通过二分法快速搜索参考矢量所在位置,通过动态调整冗余小矢量作用时间,控制流经逆变器中线电流,从而实现中点电位平衡控制;最后基于矢量法对SVPWM策略下三电平逆变器输出误差电流进行了分析。仿真结果表明,该SVPWM策略避免了三角函数计算,较60°坐标系SVPWM策略运算时间也有所降低,并可实现精细化中点电位平衡控制。
With regard to the three-level inverter, the traditional space vector pulse width modulation （SPVPWM） method neds a great deal of trigonometric function calculation and reference vector sector determination, which may increase com-putation time overhead of the controller. If considering balance of the neutral point potential, complexity of the algorithm is increased further. In addition,there are short of simple and effective evaluation methods for output waveform quality of the inverter under different SVPWM strategies. Therefore,on the basis of 60 °coordinate system SVPWM strategy,the paper presents a kind of simplified modulation strategy adopting dichotomy method which can rapidly search for locations of refer-ence vectors by using the dichotomy method and control current flowing through the center line of the inverter by dynam-- cally adjusting action time of redundant small vectors so as to realize balance control for the neutral point potential. Finally, it analyzes output tror current of the three-level inverter under SVPWM strategy based on the vector method. Simulation results indicate this SVPWM strategy has avoided trigonometric function calculation and decreased its computation time over-head compared with 60 Coordinate system SVPWM strategy. It shows this strategy can realize refined control for balance of the neutral point potential.
出处
《广东电力》
2017年第12期48-54,共7页
Guangdong Electric Power
