60°坐标系下三电平逆变器SVPWM控制策略研究

摘要

For the neutral point clamped three-level inverter,a new method for SVPWM based on 60 ° coordinate system can effectively avoid the shortcomings of complex algorithm,and the large amount of calculation which exist in space vector pulse width modulation (SVPWM) method in α-β coordinate system.In this paper,following measures are put forward,namely,60° coordinate system is adopted to improve the control algorithm,g-h coordinate system is established,the relationship between the reference vectors and space coordinates is analyzed,the algorithm of per-unit transformation of the basic voltage vector is proposed,the judgment of sectors is simplified,and acting time of the voltage vectors in sector Ⅰ is calculated.The rotation module is established,and reference voltage vectors in other sectors are rotated to sector Ⅰ,acting time of the voltage vectors is obtained directly,so the operation process is simplified and a lot of trigonometric function calculations are avoided.Based on the Matlab simulation model and experiment,the reliability of the improvement measures is verified,and the response speed of the system becomes quicker.%为解决二极管箝位型三电平逆变器直角坐标系下SVPWM算法复杂、计算量大的问题,本文采用60°坐标系对控制算法进行了改进.建立g-h坐标系,分析了参考矢量与空间坐标的关系,提出了参考电压矢量标幺变换的算法,简化了判断扇区方法,计算第Ⅰ扇区电压矢量的作用时间;建立了系统旋转模型,将其他扇区电压矢量对应到第Ⅰ扇区,直接读取矢量作用时间,简化了运算流程,避免了进行大量的三角函数运算.Matlab仿真和实验结果验证了本方法的可行性.