Power-Pitch Cascade Control-Based Approach for the Up/Down-Regulated Operation of Large Wind Turbines

Modern energy needs require controlled and clean power generation. This demands that the wind turbines be integrated into joint generation groups (wind farms) and the power supply passes be managed by the grid. In this case, the control system of both the wind farm and the individual machines needs the ability to decrease and increase the power output as required. This control system feature is normally implemented by changing control strategies and an associated switching logic. This makes the control system additionally complex and prone to errors. This paper proposes an integrated control configuration for torque and pitch based on a cascade power tracking control (PTC) approach that extends the traditional wind turbine control to enable or disable up/down-regulation. Hence, the resulting control system topology is not complex, and its theoretic dynamic behaviour is known and expected. The new control configuration is studied within a simulation environment with a 20 MW reference machine. The simulation results are very promising from the control performance viewpoint.