Impact mechanism analysis of system stability for non-minimum-phase zeros on VSC under weak coupling conditions
The right-half-plane(RHP)zeros induce non-minimum phase responses,significantly degrading the dynamic performance of control systems.This paper establishes a single iniput single output(SISO)transfer function model for the voltage source converter grid-connected system.It reveals the mechanisms by which the rectification/inversion operating modes,grid impedance,and operating conditions affect the generation of RHP zeros under weak coupling conditions.The relationship between RHP zeros and their non-minimum phase dynamics in the SISO transfer function system is explored,and the influence of RHP zeros on the dynamics of phase-locked loop(PLL)is analyzed.The correctness of the analysis is validated by MATLAB/Simulink.