Decoupling Control for Multiterminal VSC-HVDC Based Wind Farm Interconnection

In the paper multiterminal voltage source converter based HVDC (VSC-HVDC) is proposed to interconnect wind farms to AC grids. The method highlights the control at the level of wind generator cluster that comprises several permanent magnet synchronous generators without the primary converters on themselves. For the cluster control, active and reactive power decoupling scheme is applied to adjust the rotational speed of the cluster according to wind speed. The paper studies the schemes to control grid side converter based on the philosophy of linear decoupling control, which aims to control the DC voltage as well as the reactive power of VSC-HVDC. In the proposed control scheme, the two goals are achieved by controlling the q- and rf-axis components of the grid´s fundamental current. Simulation has been performed using engineering software Matlab/Simulink to verify the interconnection method and validate the control scheme as well.