三相四线制有源电力滤波器中性点电位平衡研究

Study of Neutral Point Potential Balance in Three-Phase Four-Wire Active Power Filter

针对三相四线制有源电力滤波器(APF)直流侧中性点电位不平衡的问题,通过结构分析,指出三相四线制APF的中性线电流存在直流分量是中性点电位不平衡问题产生的主因,并针对采样偏差导致的中性线电流存在直流分量问题做出说明及验证。根据系统拓扑建立数学模型,设计一种电压平衡控制方案,并给出系统整体控制框图。通过仿真和试验,验证了理论分析与均压环设计的正确性。

For three-phase four wire active power filter （APF） DC side neutral point unbalance problem, through analyzing the mathenlatical description and structure, it was pointed out that the three-phase four-wire APF line current DC component is mainly due to the unbalance of neutral point potential. The deviation of midpoint potential caused by sampling bias was explained and verified. According to the system topology, a mathenlatical model was established, and a voltage balance control scheme was designed, and the overall control block diagram of the system was given. The correctness of the theoretical analysis and the design of the balance control link was verified by the simulation and experiment.