A hybrid controller design for VSC-HVDC transmission system for PMSG based offshore wind farm

Permanent magnet synchronous generator (PMSG) based offshore wind farm is connected to the onshore grid by voltage source converter (VSC) - HVDC link. The wind farm side VSC controls the AC voltage, and grid side VSC controls the reactive power and DC link voltage. This paper presents a non-linear control method for improving the robustness of the controller for VSC-HVDC link. A hybrid controller is designed using sliding mode control (SMC) and proportional-integral (PI) control. Mathematical modeling of the hybrid controller is presented. This hybrid controller has the capability of Fault Ride-Through and transient stability of VSC-HVDC link. This hybrid controller is simulated using the MATLAB/Simulink software and it is observed that the controller provides better performance. Transient stability is ensured by creating a symmetrical fault at the grid side in the simulation.