Steady-state model for VSC based HVDC and its controller design

In this paper, a steady-state model of a VSC (voltage source converter) based HVDC system has been developed. According to this model, the corresponding relationship between the two controlling and the two controlled variables of the VSC is determined. Furthermore, a nonlinear control strategy combining an inverse model controller with a PI controller is proposed, and a nonlinear compensation method is adopted for the DC voltage PI controller. Digital simulation shows the validity of the established steady-state model and the feasibility of the proposed control strategy.