Nonlinear adaptive control design for the VSC-HVDC light transmission system

This paper proposes a nonlinear adaptive control (NAC) scheme for the voltage source converter based high voltage direct current (VSC-HVDC) light transmission system to handle various system uncertainties. The combinatorial effect of system nonlinearity, parameter uncertainties and external disturbances is aggregated into a perturbation term, which is estimated online by a perturbation observer (PO). The NAC is based on the nonlinearly functional estimation which does not require an accurate system model and only one state measurement is needed, thus it can be easily implemented in practice. The proposed approach is then applied in a standard VSC-HVDC light transmission system to maintain the DC voltage and regulate the active and reactive power. Case study has been carried out to verify its effectiveness under various operating conditions.