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 z domain

and discusses the impact on system robustness by inductance deviation. In this regard

a predictive 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 z domain

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. This work is supported by National Natural Science Foundation of China(No. 51477045)and Fundamental Research Funds for the Central Universities.