Different Control Strategies for Converter Based DC Energy Transmission in Offshore Wind Power: A Literature Survey

This paper reviews the control techniques and operational behavior of a DC energy transmission system tied with an offshore wind field using voltage source converter based high voltage direct current topologies to highlight the state of the art on different system structures, and its controllers' schemes approaches. Firstly, the technical features, configurations and technologies of VSC-HVDC for offshore located wind farm are cataloged and summarized. This includes a short discussion for the wind turbine mathematical modeling and the different driving generators types. The Survey concentrates on the recent control strategies and controller schemes development specifically for regulating the power flow control objective in VSC connected to the electric network in steady state conditions. Finally, the paper concludes with identifying the major controllers' structures and techniques that used in VSC based HVDC transmission system to enable resilience integration of the offshore wind farm to the existing power network. The surveyed controllers' techniques in this work offer an effective enhancement in many other technical issues like fluctuation of voltage, harmonics, flicker phenomena, and long distance transmission. This work may serve as a comprehensive form of reference for any forthcoming advancement in the design concept of the VSC based HVDC.