Nonlinear Control Design of VSC-MTDC Systems based on Backstepping Approach

This paper deals with the nonlinear control approach of Voltage Source Converter (VSC) based on MTDC (multi-terminal direct current) transmission systems. A nonlinear control approach based on Backstepping method is proposed for two different control methods: active power and DC voltage. The proposed control approach, based on Lyapunov theory, is capable of analytically obtaining a control laws in order to regulate the active power and dc bus voltage in an MTDC system. Furthermore, the dynamic interactions between the active power nonlinear control design and the DC voltage droop control are examined. Finally, the validity of the proposed control design approach is verified by time-domain simulations under the Matlab/Simulink environment.