Research on interaction of APFs based on relative gain array

Different APFs (Active Power Filter) interact with each other when multiple APFs are connected to the grid, and the interactions deteriorate the control performance of APFs and even lead to system instability. This paper presents a method to analyze the dynamic interaction of multiple APFs in a weak grid. This method uses the Norton equivalent principle to establish the mathematical model of a single APF. The mathematical model of the multiple APFs connected to the grid is set up based on the single APF mode. The RGA (Relative Gain Array) principle is used to analyze the interactions among multiple APFs. Besides, this paper analyzes the effect of changing circuit parameters and controller parameters on the change of the interactions. The strategy of weakening and eliminating the interaction is proposed based on rational selection and combination of parameters. Analysis, along with time domain simulation and experimental results, is presented to verify the feasibility and effectiveness of the proposed method and strategy.