有源电力滤波器采样滤波电路的优化设计及鲁棒控制

Optimization Design and Robust Control of Sampling Filter Circuit in Active Power Filter

电流采样电路的设计和电流内环的控制效果是影响有源电力滤波器(APF)补偿精度的两个重要因素。文中首先通过波特图详细分析了电阻和电容参数选取对APF电流内环的影响,提出了一种RC滤波电路的参数设计方法。同时,考虑到控制延时环节不可避免存在,分析了带延时环节的z域无差拍离散控制模型,并讨论了电感值变化对系统鲁棒性的影响。对此,文中提出了一种预测电流控制方法,对采样的电网电压,逆变器输出电流都作了超前一拍预测,减小了延时对系统影响,增强系统的鲁棒性。此外,根据z域内的电流环传递函数对系统进行了稳定性分析,给出了控制参数的选取方法。针对该控制方法,搭建了APF试验样机,实验结果验证了控制策略的有效性和可行性。

The design of current sampling circuit and the control effect of the current loop are two important factors that affect the accuracy of active power filter（APF）compensation.First of all,this paper proposes a parameter design method of RC filter circuit,and makes a detailed analysis of the RC parameter selection effect on the APF inner current loop through Bode diagram.At the same time,considering the inevitable existence of control delay,this paper analyzes the discrete deadbeat control model with time delay in the zdomain,and discusses the impact on system robustness by inductance deviation.In this regard,apredictive current control method is presented,and a two-sample forecast is made of grid voltage and inverter output current.This method reduces the impact of the delay on the system and enhances system robustness.Moreover,according to the transfer function of current loop in the zdomain,system stability is analyzed,and the range of control parameters selection given.For this control method,the APF experimental prototype is set up,the experimental results demonstrating the effectiveness and feasibility of the control strategy.