This paper is motivated by the need for improving the grid reliability of large-capacity three-level inverter. The study accomplishes this by using a closed-loop control scheme to verify the feasi-bility of simplified SVPWM algorithm without involving a large number of trigonometric functions in 60 ° coordinate system;achieving a neutral point potential balance control by dynamically adjusting redundant positive and negative short vector action time; and simulating the construction of a closed loop control model for NPC three-level SVPWM, using Matlab software. The results demonstrate that the simplified SVPWM algorithm features a higher efficiency, a better saving in processor resources, a better Sine in output voltage and current waveform of inverter, total harmonic distortion rate of current of only 3. 66%after LCL filter and above all, a small mid-point voltage shift. The scheme verifies the feasibility and ef-fectiveness of the three-level SVPWM algorithm and the mid-point balance control strategy.%为提高大容量三电平逆变器并网可靠性,利用闭环控制方案验证60°坐标系下无需大量三角函数运算的SVPWM简化算法的可行性.采用动态调整冗余正负小矢量作用时间方法实现中点电位平衡控制,运用Matlab软件对构建NPC三电平SVPWM闭环控制模型进行仿真.结果表明:SVPWM简化算法执行效率高、节约处理器资源,逆变器输出电压、电流波形正弦度较好,LCL滤波后电流谐波总畸变率仅为3.66%且中点电压偏移浮动小.该方案验证了三电平SVPWM算法及中点平衡控制策略的可行性和有效性.
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