Stability analysis and a hybrid controller design of grid-connected offshore wind farm through a VSC-HVDC transmission link

Abstract

This paper proposes a hybrid controller which is a combination sliding mode control and PI control techniques for AC grid integrated offshore wind farm (OSWF) with voltage source converter - high voltage direct current system. The controller must be capable of controlling AC voltage, DC-link voltage, reactive power and effective power transfer. To examine the FRT capability, a symmetrical fault is applied at onshore AC grid side and compared the performances of the studied system based on the hybrid and PI controllers. The dynamic modelling and linearized system by state-space modelling for the studied system are explained in detail. The small signal stability analysis and controller stability are observed with the help of the eigenvalue analysis. The analysis of the studied system with a hybrid and conventional controllers are conducted in the software environment of the MATLAB/SIMULINK. The effect of parameter uncertainty on total system stability is examined with the help of eigenmatrix of the studied system. © 2019 Chinese Automatic Control Society and John Wiley & Sons Australia, Ltd