Analysis on interactive influences among control loops of multi inverters connected to weak-structured power system

摘要

Long-distance power transmission and the increasing number of grid-connected inverters make multi inverters grid-connected power network equivalent impedance non-ignorable under the weak-structured power system. The existence of power network equivalent impedance couples multiple inverters in PCC, and then causes the complex interactive influences among control loops of multi inverters grid-connected system. The equivalent model of multi inverters connected to weak-structured power system was established, dynamic relative gain array based on frequency was used to quantitative analysis the interactive influences among control loops of multi inverters and give interactive change characteristics with the changing grid-connected inverter units, control parameters and power grid equivalent impedance. Finally, a multi inverters grid-connected was built in Simulink simulation platform, the correctness of simulation results were verified. Meanwhile, general rules of changing interactive influences among control loops with the increasing number of inverters grid-connected were accurate descripted.