Wind turbine rotational system
Method of operating a wind turbine rotational system having a plurality of drives and a central control system (CCS), each drive having a motor and an electronic converter. The CCS sends speed and torque setpoints to the electronic converters, and the electronic converters drive the motors in accordance with said setpoints. The method comprises designating one of the drives as master drive and the other drives as slave drives. The method also comprises the CCS determining a master speed setpoint and a master torque setpoint, and sending said setpoints to the master drive. The method further comprises the CCS obtaining the real torque and speed of the motor of the master drive and sending a slave speed setpoint and a slave torque setpoint to each slave drive, said slave speed setpoint based on the master speed setpoint and said slave torque setpoint equal to the obtained real torque of the master drive.
1. A method of operating a wind turbine yawn control or pitch control rotational system comprising a plurality of drives in the yaw control or the pitch control rotational system and a central control system, each drive comprising a motor, each motor in driving engagement through an actuator with a common annular gear, and an electronic converter for driving the motor and the actuator operatively connected with the motor, wherein
the central control system sends speed setpoints and torque setpoints to the electronic converters and the electronic converters drive the motors in the yaw control or the pitch control rotational system in accordance with the received setpoints,
the method comprising:
designating one of the drives in the yaw control or pitch control rotational system as a master drive and designating the other drives in the yaw control or pitch control rotational system as slave drives,
the central control system determining a master speed setpoint and a master torque setpoint,
the central control system sending the master speed setpoint and the master torque setpoint to the master drive in the yaw control or pitch control rotational system,
the central control system obtaining, from the master drive, values representing the real torque and speed of the motor of the master drive,
and the central control system sending a slave speed setpoint and a slave torque setpoint to each of the slave drives in the yaw control or pitch control rotational system, wherein the slave speed setpoint is based on the master speed setpoint, and wherein the slave torque setpoint is equal to the value representing the real torque of the master drive:
determining, from the values representing the real speed and torque of the master drive, whether the motor of the master drive is acting as a motor or as a generator and, wherein
the slave speed setpoint is equal to the master speed setpoint plus a predetermined offset value when the motor of the master drive is acting as a motor, and
the slave speed setpoint is equal to the master speed setpoint minus the predetermined offset value when the motor of the master drive is acting as a generator.
2. A method according to claim 1 , wherein the slave speed setpoint is the same for all the slave drives.
3. A method according to claim 1 , wherein the predetermined offset value is a variable offset value.
4. A method according to claim 3 , wherein the variable offset value is determined in accordance with a PID control based on a difference between the value representing the real speed of the master drive and the master speed setpoint.
5. A wind turbine yaw control or pitch control rotational system comprising
a plurality of drives in the yaw control or pitch control rotational system and a central control system,
each drive comprising a motor,
each motor in driving engagement through an actuator with a common annular gear in the yaw control or the pitch control rotational system, an electronic converter for driving the motor and the actuator operatively connected with the motor,
wherein in the yaw control or pitch control rotational system one of the drives is designated as a master drive and the other drives are designated as slave drives,
The central control system configured for:
Determining a master speed setpoint and a master torque setpoint,
Sending the master speed setpoint and the master torque setpoint to the master drive in the yaw control or pitch control rotational system,
Obtaining, from the master drive, values representing the real torque and speed of the motor of the master drive
Sending a slave speed setpoint and a slave torque setpoint to each of the slave drives in the yaw control or pitch control rotational system, wherein the slave speed setpoint is based on the master speed setpoint, and wherein the slave torque setpoint is equal to the value representing the real torque of the master drive;
determining, from the values representing the real speed and torque of the master drive, whether the motor of the master drive is acting as a motor or as a generator and wherein
the slave speed setpoint is equal to the master speed setpoint plus a predetermined offset value when the motor of the master drive is acting as a motor, and
the slave speed setpoint is equal to the master speed setpoint minus the predetermined offset value when the motor of the master drive is acting as a generator.
6. A wind turbine rotational system according to claim 5 , wherein the slave speed setpoint is the same for all the slave drives.
7. A wind turbine rotational system according to claim 5 , wherein the predetermined offset value is a variable offset value.
8. A wind turbine rotational system according to claim 7 , wherein the variable offset value is determined in accordance with a PHD control based on a difference between the value representing the real speed of the master drive and the master speed setpoint.