Power management system

1. A power control system for optimizing power production from a yaw controlled two-bladed wind turbine,

wherein the wind turbine is programmed, through a controller, a yaw actuation subsystem and a drivetrain restraining torque subsystem, and by using sensed output power of the wind turbine, sensed rotor running speed of the wind turbine and sensed wind direction relative to rotor axis direction of the wind turbine, to determine an optimal operational mode based on a level of the output power,

wherein when the sensed output power has a value that is less than power of the wind turbine at rated rotor torque of the wind turbine, the controller is programmed to:

instruct the yaw actuation subsystem to maintain the rotor axis aligned with the wind, so as to have a yaw angle that is zero;

calculate rotor running speed corresponding to a desired Tip Speed Ratio (TSR);

compare the calculated rotor running speed to the sensed rotor running speed; and

instruct the drivetrain restraining torque subsystem to change the drivetrain restraining torque until actual rotor running speed reaches the calculated value corresponding to the optimal desired TSR.

2. The power control system of claim 1 , wherein the yaw actuation subsystem is hydraulic or electrical and the drivetrain restraining torque subsystem comprises an electrical generator coupled to an electrical converter.

3. The power control system of claim 1 , wherein the wind turbine has two blades and a teetering hub.

4. A power control system for optimizing power production from a yaw controlled two-bladed wind turbine,

wherein the wind turbine is programmed, through a controller, a yaw actuation subsystem and a drivetrain restraining torque subsystem, and by using sensed output power of the wind turbine, sensed rotor running speed of the wind turbine and sensed wind direction relative to rotor axis direction of the wind turbine, to determine an optimal operational mode based on a level of the output power,

wherein when the sensed output power is greater than power of the wind turbine at rated wind speed but less than power of the wind turbine at cut-out wind speed, the controller is programmed to:

instruct the drivetrain restraining torque subsystem to maintain the drivetrain restraining torque constant and at its rated value;

calculate a desired rotor running speed, which shall be between rated rotor running speed and maximum rotor running speed, based on power level and sensed yaw angle;

compare the desired rotor running speed to the sensed rotor running speed; and

instruct the yaw actuation subsystem to change the yaw angle until the sensed rotor running speed reaches the desired rotor running speed.

5. The power control system of claim 4 , wherein when the sensed output power is substantially at the power at cut-out, the controller is programmed to:

instruct the drivetrain restraining torque subsystem to maintain the drivetrain restraining torque constant and at its rated value;

set the desired rotor running speed to the maximum running speed;

compare the maximum rotor running speed with the sensed rotor running speed; and

instruct the yaw actuation subsystem to change the yaw angle until the sensed rotor running speed and the maximum rotor running speed are substantially equal.

6. The power control system of claim 4 , wherein the yaw actuation subsystem is hydraulic or electrical and the drivetrain restraining torque subsystem comprises an electrical generator coupled to an electrical converter.

7. The power control system of claim 4 , wherein the wind turbine has two blades and a teetering hub.