Electric linear motor

Patent metadata

Field	Value
Publication number	US-10689227-B2
Application number	US-201916273310-A
Country	US
Kind code	B2
Filing date	Feb 12, 2019
Priority date	Mar 28, 2018
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

The invention refers to an electric linear motor, control apparatus, transport system and a method. The electric linear motor comprises a longitudinal stator beam; at least one mover at least partially surrounding the stator beam and adapted to move along the stator beam; which stator beam comprises at least two side faces located at opposite sides of the stator beam, each of the side faces carrying ferromagnetic poles spaced apart by a pitch, and which mover comprises at least two counter-faces facing the respective side faces of the stator beam. The mover has in at least one of said counter-faces rotor units having at least one winding and at least one permanent magnet arranged to co-act with the ferromagnetic poles of the respective side faces of the stator beam. The ferromagnetic stator poles of the stator beam and the rotor units of the mover are used for generating propulsion forces for driving the mover along the stator beam as well as for generating attraction forces to levitate the mover around the stator beam while driving.

First claim

The invention claimed is:

1. A transport system, comprising:
an electric linear motor including,
a stator beam including at least two side faces at opposite sides of the stator beam, each of the at least two side faces including ferromagnetic poles spaced apart by a pitch, and
a mover configured to move along the stator beam the mover including at least two counter-faces facing respective ones of the at least two side faces of the stator beam, at least one of the counter-faces including at least one rotor unit having at least one winding and at least one permanent magnet, such that the at least one winding and the at least one permanent magnet associated with the mover are configured to co-act with the ferromagnetic poles of the respective ones of the at least two side faces of the stator beam; and

a control apparatus configured to,
obtain position information of a mutual position of the ferromagnetic poles and the at least one rotor unit facing said ferromagnetic poles, the position information being obtained in a travelling direction of the rotor unit,
represent d,q-coordinate system of the at least one rotor unit based on the position information such that a d-axis of the at least one rotor unit is in a direction of the ferromagnetic poles facing the at least one rotor unit and a q-axis of the at least one rotor unit is orthogonal to the d-axis,
obtain information of a length of an air gap between the ferromagnetic poles and the at least one rotor unit facing the ferromagnetic poles, and
supply, via at least one drive unit, a d-axis current component to the at least one winding of the at least one rotor unit to adjust the length of the air gap towards an air gap reference value, the d-axis current component being established based on a difference between the air gap reference value and the length of the air gap.

2. The transport system according to claim 1 , wherein each of the at least two counter-faces includes a respective one of the at least one rotor unit such that each of the at least two counter-faces includes a respective one of the at least one winding and the at least one permanent magnet.

3. The transport system according to claim 1 , wherein
the at least two side faces of the stator beam includes at least four side faces located two by two at opposite sides of the stator beam, such that the at least four side faces substantially cover a circumference of the stator beam, each of the at least four side faces carrying ferromagnetic poles spaced apart by a pitch, and
the at least two counter-faces of the mover includes at least four counter-faces facing respective ones of the at least four side faces of the stator beam, each of the at least four counter-faces including a respective one of the at least one rotor unit such that each of the at least four counter-faces includes a respective one of the at least one winding and the at least one permanent magnet.

4. The transport system according to claim 1 , wherein
the stator beam is a ferromagnetic stator rod, and
the ferromagnetic poles are teeth provided on a side face of the ferromagnetic stator rod such that the teeth are spaced apart by teeth gaps.

5. The transport system according to claim 1 , wherein the at least two side-faces carrying ferromagnetic poles of the stator beam do not include any of the at least one winding and the at least one permanent magnet.

6. The transport system according to claim 1 , wherein each of the at least one rotor unit includes respective ones of the at least one winding and the at least one permanent magnet, each of the at least one winding being a three-phase motor winding.

7. The transport system according to claim 1 , wherein the at least one rotor unit associated with each of the at least two counter-faces of the mover includes at least two rotor units arranged consecutively in a travelling direction, each of the at least two rotor units having a respective one of the at least one winding and the at least one permanent magnet.

8. The transport system according to claim 1 , wherein each of the at least one rotor unit includes at least two rotors having windings connected in series or in parallel.

9. A control apparatus of an electric linear motor including a stator beam and a mover configured to move along the stator beam, the stator beam including at least two side faces at opposite sides of the stator beam, each of the at least two side faces including ferromagnetic poles spaced apart by a pitch, and the mover including at least two counter-faces facing respective ones of the at least two side faces of the stator beam, at least one of the counter-faces including at least one rotor unit having at least one winding and at least one permanent magnet, such that the at least one winding and the at least one permanent magnet associated with the mover are configured to co-act with the ferromagnetic poles of the respective ones of the at least two side faces of the stator beam, wherein the control apparatus comprises:
at least one drive unit configured to supply electrical power to the at least one rotor unit of the mover; and
processing circuitry configured to,
obtain position information of a mutual position of the ferromagnetic poles and the at least one rotor unit facing said ferromagnetic poles, the position information being obtained in a travelling direction of the rotor unit,
represent d,q-coordinate system of the at least one rotor unit based on the position information such that a d-axis of the at least one rotor unit is in a direction of the ferromagnetic poles facing the at least one rotor unit and a q-axis of the at least one rotor unit is orthogonal to the d-axis,
obtain information of a length of an air gap between the ferromagnetic poles and the at least one rotor unit facing the ferromagnetic poles, and
supply, via at least one drive unit, a d-axis current component to the at least one winding of the at least one rotor unit to adjust the length of the air gap towards an air gap reference value, the d-axis current component being established based on a difference between the air gap reference value and the length of the air gap.

10. The control apparatus according to claim 9 , wherein the at least one drive unit comprises:
a plurality of drive units configured to supply electrical power separately to respective ones of the at least one rotor unit of the mover such that each of the at least one rotor unit is supplied by a separate one of the plurality of drive units.

11. A transport system comprising:
the control apparatus according to claim 9 ;
the electric linear motor; and
a mobile load-receiving part coupled to the mover and arranged to travel along a trajectory defined by the stator beam via a propulsion force of the mover.

12. The transport system according to claim 1 , wherein the mover includes one or more movers each connected to a respective elevator car, the stator beam extends longitudinally along an elevator shaft and does not include any of the at least one winding and the at least one permanent magnet fixed thereto such that along a length of the elevator shaft only the one or more movers connected to the respective elevator car includes the at least one winding and the at least one permanent magnet.

13. A method of controlling an electric linear motor, the electric linear motor including a stator beam and a mover configured to move along the stator beam, the stator beam including at least two side faces at opposite sides of the stator beam, each of the at least two side faces including ferromagnetic poles spaced apart by a pitch, and the mover including at least two counter-faces facing respective ones of the at lea

Assignees

• Kone Corp

Inventors

• Korhonen Tuukka
• Hakala Tero
• Raassina Pasi
• Suur-Askola Seppo
• Hinkkanen Marko
• Saarakkala Seppo
• Sokolov Maksim
• Hosseinzadeh Reza

Classifications

• H02P25/06

  Linear motors · CPC title

• H02K7/08

  Structural association with bearings · CPC title

• B66B7/044

  with magnetic or electromagnetic means · CPC title

• H02K7/09

  with magnetic bearings · CPC title

• B66B9/003

  for lateral transfer of car or frame, e.g. between vertical hoistways or to/from a parking position · CPC title