三相四线制三电平变换器简化调制策略

摘要

针对三相四线制三电平电容中分式变换器传统的复杂三维(3D)空间矢量脉宽调制(SVPWM)算法,提出基于矢量状态的简化PWM策略,采用矢量状态扩展实现中点平衡控制.通过分析各矢量状态对中点电位的影响,总结了中点平衡因子的表达式.利用伏秒平衡原理,根据三相矢量状态直接计算出各相矢量状态作用时间.基于中点平衡因子,提出矢量状态扩展实现中点电位控制.仿真和实验验证了所提策略的正确性.%To tranditional complex three-dimensional (3D) space vector pulse width modulation(3D-SVPWM) applied in three-phase four-wire tri-level mid-point capcitor converter,a novel PWM strategy based on vector state is proposed.The neutral point potential is controlled by vector state expansion.Based on the analysis of the influence of the vector state on the neutral point potential,the expression of the neutral point balance factor is summarized.According to the principle of the voltage-second balance,the working time of the vector state of each phase is directly calculated by using the three-phase vector state.Based on the neutral point balancing factor,the vector state expansion is proposed to realize the neutral point potential control.Simulation and experimental result shows the correctness of the new strategy.