中点平衡问题是三相四线制三电平三桥臂有源电力滤波器(active power filter,APF)的一个固有问题,目前在矢量调制中尚无完善的控制理论完全解决此问题。该文通过对各种电流电压状态下每个三维空间矢量对直流中点电位的影响进行分析,提出...中点平衡问题是三相四线制三电平三桥臂有源电力滤波器(active power filter,APF)的一个固有问题,目前在矢量调制中尚无完善的控制理论完全解决此问题。该文通过对各种电流电压状态下每个三维空间矢量对直流中点电位的影响进行分析,提出了"中点控制度"(neutral-point control grades,NPCG)的概念,并给出了NPCG的计算公式;基于NPCG,在α-β-0坐标系下提出一种基于坐标平移原理的新型"三维矢量优化选择调制策略"(optimized3D space vector modulation,O3DSVM),该调制策略能优化选择NPCG值较高的矢量以合成目标矢量,从而达到最大程度控制直流中点电位偏移的目的。仿真分析验证了中点控制度理论及O3DSVM调制策略的正确性和可行性,采用该策略的APF不但中点电位得到了有效控制,且补偿效果良好。展开更多
An analytical evaluation method for output waveform quality of space vector pulse width modulation(PWM)strategies applied in neutral⁃point⁃clamped three⁃level converter(3L⁃NPC)is proposed in this paper.Low frequency e...An analytical evaluation method for output waveform quality of space vector pulse width modulation(PWM)strategies applied in neutral⁃point⁃clamped three⁃level converter(3L⁃NPC)is proposed in this paper.Low frequency error caused by neutral point voltage ripple and high frequency error introduced by space vector synthesis were both taken into account,and the unified error model of output current ripple was established.By taking continuous and discontinuous modulation strategies as examples,the unified error model was validated through Fourier analysis of the experimental results.The proposed evaluation method will be helpful for the switching sequence optimization and the modulation strategy selection.展开更多
文摘中点平衡问题是三相四线制三电平三桥臂有源电力滤波器(active power filter,APF)的一个固有问题,目前在矢量调制中尚无完善的控制理论完全解决此问题。该文通过对各种电流电压状态下每个三维空间矢量对直流中点电位的影响进行分析,提出了"中点控制度"(neutral-point control grades,NPCG)的概念,并给出了NPCG的计算公式;基于NPCG,在α-β-0坐标系下提出一种基于坐标平移原理的新型"三维矢量优化选择调制策略"(optimized3D space vector modulation,O3DSVM),该调制策略能优化选择NPCG值较高的矢量以合成目标矢量,从而达到最大程度控制直流中点电位偏移的目的。仿真分析验证了中点控制度理论及O3DSVM调制策略的正确性和可行性,采用该策略的APF不但中点电位得到了有效控制,且补偿效果良好。
基金National Natural Science Foundation of China(Grant Nos.51807140 and 51690183).
文摘An analytical evaluation method for output waveform quality of space vector pulse width modulation(PWM)strategies applied in neutral⁃point⁃clamped three⁃level converter(3L⁃NPC)is proposed in this paper.Low frequency error caused by neutral point voltage ripple and high frequency error introduced by space vector synthesis were both taken into account,and the unified error model of output current ripple was established.By taking continuous and discontinuous modulation strategies as examples,the unified error model was validated through Fourier analysis of the experimental results.The proposed evaluation method will be helpful for the switching sequence optimization and the modulation strategy selection.
