Method and long stator linear motor for transferring a transport unit at a transfer position

1. A method for transferring a transport unit of a long stator linear motor at a transfer position from a first transport section, having a number of driving coils arranged on a first guide structure one behind the other in a direction of movement of the transport unit in a region of the transfer position, to a second transport section, having a number of driving coils arranged on a second guide structure one behind the other in a direction of movement of the transport unit in the region of the transfer position, wherein, on each side of the transport unit, excitation magnets are arranged to interact with driving coils in a region of the transport unit, wherein on both sides of the transport unit excitation-magnetic lateral forces are acting on the transport unit by an interaction of the excitation magnets with ferromagnetic components of the first and second guide structures, comprising:

supplying on at least one side of the transport unit a stator current in at least one driving coil in the region of the transfer position that generates a lateral force-forming electromagnetic force that acts on the transport unit, so that a resulting lateral force, as a sum of the acting excitation-magnetic lateral force and of the lateral force-forming electromagnetic force, on each side of the transport unit is different to produce a steering effect on the transport unit at the transfer position.

2. The method according to claim 1 , wherein the lateral force-forming electromagnetic force is produced on both sides of the transport unit.

3. The method according to claim 2 , wherein the lateral force-forming electromagnetic forces produced on both sides of the transport unit are generated in a same direction.

4. The method according to claim 2 , wherein lateral force-forming electromagnetic forces produced on both sides of the transport unit are generated in different directions.

5. The method according to claim 1 , wherein several driving coils interact with excitation magnets on the transport unit at a same time and the stator current is supplied in at least one of the several driving coils.

6. The method according to claim 1 , wherein a propulsive force acting on the transport unit is controlled with a propulsive force forming current component of the stator current and the steering effect is controlled at the transfer position with a lateral force forming current component of the stator current.

7. The method according to claim 6 , wherein the propulsive force is controlled with a position controller for controlling a position of the transport unit, said position controller determines the propulsive force forming current component from a position error that is determined with a desired position and an actual position.

8. The method according to claim 6 , wherein the steering effect is controlled with a steering controller, said steering controller determines the lateral force forming current component from a flux error as the difference between a desired flux and an actual flux.

9. The method according to claim 6 , wherein the lateral force-forming electromagnetic force is superimposed on the propulsive force.

10. The method according to claim 9 , wherein the stator current in the at least one driving coil in the region of the transfer position further generates a propulsion force-forming electromagnetic force that acts on the transport unit, which provides further steering of the transfer unit.

11. The method according to claim 10 , wherein the propulsive force-forming electromagnetic force is superimposed on the propulsive force.

12. The method according to claim 5 , wherein the several driving coils interact with excitation magnets on the transport unit at the same time and the stator current is supplied in only one of the several driving coils.

13. The method according to claim 5 , wherein the several driving coils interact with excitation magnets on the transport unit at the same time and a stator current is supplied in all of the several driving coils.

14. The method according to claim 6 , wherein the stator current in the at least one driving coil is supplied as a current vector with a lateral force-forming electromagnetic component.

15. The method according to claim 14 , wherein the current vector further includes a propulsive force-forming electromagnetic component.

16. The method according to claim 15 , wherein the steering effect is controlled with a steering controller that compensates for a flux error as a difference between a desired flux and an actual flux, and determines the lateral force-forming electromagnetic component of the stator current, and

wherein the propulsive force is controlled with a position controller that compensates for a position error as a difference between a desired position and an actual position, and determines the propulsive force-forming electromagnetic component of the stator current.