Admittance Modeling and Control Parameter Analysis of DC-Side Converters

The stability issues of novel power systems with obvious power electronic characteristics are becoming increasingly severe. In order to better analyze the transient stability of the system, it is necessary to built a more accurate mathematical model of the Voltage Source Converter (VSC) in High Voltage Direct Current (HVDC) systems. This paper incorporates the impact of DC voltage fluctuations into the relationship between the modulation signal and the DC-side voltage, establishing a more accurate global state-space small-signal model for VSC-HVDC systems. This model is used to analyze the impact of control parameters on the system's transient stability and tune the control parameters. Finally, simulation models and small-signal calculation models of the VSC-HVDC system are built in PSCAD/EMTDC and Matlab, respectively. The simulation results of the two are compared to verify the accuracy of the established model.