Control and Analysis for a 5MW Offshore Wind Turbine Combining with Direct-Drive Permanent Magnet Synchronous Generator and Grid

This paper aims to investigate dynamic simulation and analysis for a 5MW wind turbine by combining the software of FAST, ADAMS and MATLAB/SIMULINK. FAST serves to build the motion models of tower, blades and nacelle of the wind turbine, and the aerodynamic analysis of blade. ADAMS is used for dynamic simulation of wind turbines. MATLAB/SIMULINK is used to establish the subsystem dynamic models for analysis and design of wind turbines. The subsystems comprise the direct-drive permanent magnet synchronous generator mathematical model with the magnetic field oriented control and grid-side converter control, the variable speed pump-controlled hydraulic servo system and the blade variable pitch angle control system, the AC induction motor driving nacelle yaw system. Finally, through combining the models of FAST, ADAMS and MATLAB/SIMULINK, the wind turbine operation and control strategies can be implemented and verified in der different wind conditions. When the wind turbine operates above cut-in speed and under the rated wind speed, the variable speed control of direct drive permanent magnet synchronous generator is performed to make the wind turbine rotor tracking the desired rotor speed calculated by the optimal tip speed ratio for maintaining the maximum power coefficient and optimum power output. When the wind turbine operates above the rated wind speed, the blade pitch control driven by the pump-controlled hydraulic servo system is implemented to adjust the pitch angle of the blades and maintain the rated power output. Different wind conditions are given for verifying the developed overall dynamic simulation of offshore wind turbines.