DC Terminal Impedance Model of Voltage Source Converter With DC Voltage Control

DC terminal impedance model of voltage source converter (VSC) is needed in the stability analysis of multi-terminal HVDC (MTDC) system. This paper develops DC terminal small-signal impedance model for the conventional three-phase two-level VSC with DC voltage control and PLL. The influence of PLL, current and voltage control on impedance are analyzed. Experimental measurements verify the model and analysis.