Dynamic interaction analysis of two-parallel active power filter

Due to the characteristics of active power filter (APF) in fast tracking and eliminating harmonic, a large number of APFs are installed in distribution network to ensure the safe operation of distribution network. However, as a lot of APF devices access to distribution network in no plan, the dynamic interaction among the APFs needs to be treated seriously and sensitively. Aiming at the interaction problems among the APFs, the typical two-parallel-APF system is taken as the research object in this paper, using the method of equivalent output impedance two-parallel-APF system equivalent model is established considering the steady-state error of a single APF system. Not only is the intrinsic correlation of the electrical and control parameters with the two-parallel-APF system discussed, but also the influence of steady state error of one APF on the operation stability of another APF is analyzed under the background of weak grid. Then, from the point of control theory, the two-parallel-APF system interaction mechanism is illustrated. The analytical method presented in this paper is validated by detailed simulation.