Abstract:  An improved algorithm is proposed that mainly focused on neutral point potential balance control of the diode clamped three-level active power filter in this paper. Firstly, this paper describes the cause of neutral point potential fluctuation in DC-side of three-level active power filter, and analyzes the control principles. In actual work, the main circuit state of active power filter is often required to switch between the rectifier and inverter, so it is difficult to determine the appropriate balance factor. This paper conducts a thorough study, and takes the fuzzy control method to solve this problem. The study found that the problem was solved by introducing fuzzy control into the balance control of the midpoint potential. Finally, the effectiveness of this method is verified by simulation and experimental results.

Key words: Neutral point potential, balance control, balance factor, fuzzy control

摘要： 针对二极管钳位型三电平有源滤波器中点电位平衡的控制算法进行了改进。阐述了三电平有源电力滤波器主电路直流侧中点电位波动的产生原因，分析了平衡因子调节中点电位的控制原理，指出了有源电力滤波器在实际工作中主电路的状态常常需要在整流和逆变两种状态之间进行切换，导致难以确定合适的平衡因子。研究发现，将模糊控制引入到中点电位的平衡控制后，解决了此问题。最后通过仿真和实验结果验证了该方法的有效性。

关键词: 中点电位, 平衡控制, 平衡因子, 模糊控制