Analysis on Interactive Influences among Multiple APFs Connected to Weak-structured Power System

When multiple active power filters (APF) are incorporated into the regional distribution network, there are complex negative interaction effects among the control circuits, resulting in the decline of APF compensation performance and harm to the stability of power system. Firstly, a multi-APF grid-connected mathematical model under the condition of weak power grid is established based on NORTON equivalent circuit. And then, combined with the dynamic relative gain array (DRGA) principle, a quantitative analytical method is proposed for analyzing the interaction degree between multiple APF control circuits, which can analyze the quantitative relationship between the interaction degree, the control circuit parameters and the weak grid equivalent inductance based on different frequency intervals. Finally, the MATLAB/Simulink platform is used to build a grid-connected simulation system model. The time-domain simulation results are consistent with the theoretical analysis, which verifies the effectiveness of the proposed method.