基于模糊控制的VSVPWM中点电位平衡策略

VSVPWM neutral-point potential balancing strategy based on fuzzy control

针对中点钳位型(NPC)三电平逆变器存在的直流侧中点电位不平衡问题,提出了一种基于模糊控制的中点电位平衡策略。该策略重新定义了虚拟空间矢量,使虚拟小矢量不引起中点电位波动,并在虚拟中矢量中引入了对中点电位不平衡有抑制作用的控制因子Q。同时,设计了由模糊控制器A和B构成的组合模糊控制器,该控制器能够依据中点电位偏移情况调整控制因子Q,实现对中点电位的闭环控制。仿真和实验结果表明,采用该策略的NPC型三电平逆变器中点电位不平衡问题能得到有效改善。

A neutral-point potential balancing strategy based on fuzzy control is proposed to solve the problem of DC neutral-point potential imbalance in NPC three-level inverter.The strategy redefines the virtual space vector so that the virtual small vector does not cause the neutral point potential fluctuation,and introduces the control factor Q into the virtual medium vector,which can inhibit the neutral point potential imbalance.At the same time,a combined fuzzy controller composed of fuzzy controller A and B is designed.The controller can adjust the control factor Q according to the neutral point potential deviation to realize the closed-loop control of neutral-point potential.Simulation and experimental results show that the neutral-point potential imbalance problem of NPC three-level inverter using this strategy can be effectively improved.