HK40000844A - Wireless power transfer arrangement for an elevator car and an elevator - Google Patents

Description

Wireless power transmission device for elevator car and elevator

Technical Field

The present invention generally relates to the field of elevator technology. However, the invention relates particularly to a wireless power transfer device of an elevator car of an elevator.

Background

Elevators have traditionally been operated by utilizing a hoisting motor along with one or more hoisting ropes for moving within or along a hoistway or elevator shaft and one or more wired power lines, such as electrical cables, routed to the elevator car for providing electrical power to electrical equipment disposed to the elevator car.

At present, elevators are often installed in objects where the travel height of the elevator may exceed the mechanical strength of the ropes and/or cables of conventional elevators, such as in the case of very tall buildings, and/or the swinging or bending of the building due to e.g. wind can present challenges to the operation of the elevator.

Still further, a multi-car elevator (i.e., an elevator having more than one elevator car) in which a hoistway or shaft operates will face similar challenges associated with electrical cables. Therefore, power must be provided to the elevator car by other means.

Therefore, there is a need to develop elevators, especially for very high buildings, to overcome the challenges related to the height of the hoistway or shaft, which may be too high for the ropes and/or cables to bear their own weight and/or the weight of the elevator car. Since the hoistway or shaft is not empty for one or more ropes and one or more electric cables due to the multiple elevator cars residing in the elevator shaft of the elevator relative to conventional elevators, there is also a need to develop a power supply for multi-car elevators.

Disclosure of Invention

The object of the invention is to provide a wireless power transmission device for an elevator car of an elevator and an elevator using a wireless power transmission device. Another object of the invention is that the wireless power transfer device and the elevator at least alleviate the problems associated with known attempts at electric cables running in the elevator shaft and providing electric power to the elevator car.

The object of the invention is achieved by a wireless power transfer device and an elevator according to the invention.

According to a first aspect, a wireless power transfer device for an elevator car of an elevator is provided. The wireless power transfer device comprises primary winding units arranged remotely with respect to each other at a first location of an elevator shaft along which the elevator car is configured to move, wherein each primary winding unit comprises at least a primary winding. By "remote with respect to each other" is meant herein primary winding units that are separated from each other by a distance that requires them to form a discontinuous set of windings in the elevator shaft. Preferably, the primary winding unit can also be galvanically divided. The wireless power transfer device further comprises at least one secondary winding unit arranged to the elevator car, wherein each of the at least one secondary winding unit comprises at least one secondary winding. Still further, each of the primary winding units and the at least one secondary winding unit are arranged such that there is a gap between said winding units for enabling the at least one secondary winding unit to be moved relative to the primary winding unit and for establishing an inductive coupling between the secondary winding and the primary winding whenever one of the at least one secondary winding unit and one of the at least one primary winding unit comprising said winding are arranged to face each other at one of the first positions in which said one of the primary winding units is arranged (i.e. e. at an intended charging position, for example).

"winding" is used herein to mean an entity that may include, for example, a coil or a set of coils. For example, the coils of the winding may be arranged to form a single phase winding or a three phase winding, and may thus be electrically connected or separated, such as in series or in parallel.

The elevator car may comprise a first energy storage, such as one or more batteries, mounted to the elevator car and coupled to the secondary winding unit for providing power to electrical equipment and appliances comprised in the elevator car.

The primary winding unit may include ferromagnetic teeth around which the primary winding is wound.

The at least one secondary winding unit may include ferromagnetic teeth around which the secondary winding is wound.

The primary winding or the secondary winding or both may be overlapping windings. This means that the coils of the primary winding may overlap each other and the coils of the secondary winding may overlap each other.

The primary winding may be arranged to teeth of a stator comprised in a stator beam of a linear motor of the elevator.

The secondary winding may be arranged to the teeth of the mover, i.e. to the teeth of the armature of the mover of the linear motor of the elevator.

The remotely arranged primary winding elements may be electrically separated from each other, i.e. there is no direct conduction path for current between the primary winding elements. The distally arranged primary winding element may have a distance of at least one meter between two consecutive primary winding elements.

Each of the primary winding units may comprise an energy storage, i.e. a second energy storage, for minimizing instantaneous power and current peaks. Wireless power transfer via inductive coupling between the secondary winding and the primary winding is possible whenever at least one secondary winding unit is in a first position facing the primary winding unit. By "instantaneous power and current peaks" is herein meant the situation where the power for wireless power transfer is drawn from the main power supply of the elevator. The second energy store may then be utilised such that at least a portion of the power is drawn from the second energy store, thereby reducing the power drawn by the primary winding unit from the mains supply. Further, the second energy store may be charged at a low power during periods when the at least one secondary winding unit is not at the corresponding first position.

A second energy store may also be coupled to several primary winding units.

According to one or more embodiments, the primary winding unit comprises a switching unit coupled to the primary winding, the switching unit having an input for receiving a power supply control signal from the elevator control unit, and the switching unit is configured to provide an AC (alternating current) voltage to the primary winding based on the power supply control signal.

According to a second aspect, an elevator is provided, comprising an elevator shaft along which an elevator car of the elevator is configured to move. The elevator comprises at least two primary winding units arranged to at least two remotely arranged first locations of the elevator shaft; and at least one secondary winding unit arranged to the elevator car. Each of the primary winding units includes a primary winding, and the at least one secondary winding unit includes a secondary winding. The winding units are arranged such that there is a gap between them such that at least one secondary winding unit is movable relative to a primary winding unit during movement of the elevator car. The winding units are adapted to form an inductive coupling between the windings for wireless power transfer between the windings whenever the elevator car is arranged at one of the at least one first position.

According to one or more embodiments, an elevator may comprise:

an elevator control unit for controlling elevator car movement;

a position sensor adapted to sense a position of the elevator car, the position sensor being connected to an elevator control unit;

wherein the elevator control unit is configured to form the power supply control signal when the position sensor indicates that the elevator car has reached or is about to reach the desired charging position;

and wherein the primary winding unit may comprise a switching unit coupled to the primary winding of the primary winding unit, the switching unit having an input for receiving a power supply control signal from the elevator control unit,

and wherein the switching unit is configured to provide the AC voltage to the primary winding based on the power supply control signal.

The switching unit may comprise one or more controllable switches, such as one or more relays, one or more IGBT (insulated gate bipolar transistor) transistors, one or more MOSFET (metal oxide semiconductor field effect transistor) transistors, etc.

According to an embodiment, the expected charging position may be recorded into the memory of the elevator control unit. The first energy store may comprise determination means for determining a charging state of the first energy store. The first energy store may be connected to the elevator control unit via a data link, preferably a wireless link or data line of a travelling cable, for indicating the charging requirement of the first energy store. The elevator control unit may be configured to command the elevator car to stop to a desired charging position in response to receiving a charging demand of the first energy store.

The primary winding units may be galvanically separated with respect to each other. The primary winding element may have a distance of at least one meter between two consecutive primary winding elements.

The primary winding or the secondary winding or both may be overlapping windings.

The primary winding may be arranged to a stator comprised in a stator beam of a linear motor of the elevator.

The secondary winding may be arranged to a mover of a linear motor of the elevator.

Each of the primary winding units comprises a second energy store for minimizing instantaneous power and current peaks. A second energy store may also be coupled to several primary winding units.

The wireless power transfer means provides an advantage over known solutions such that power can be provided wirelessly to the elevator car at a first location of the elevator shaft and without the need to have a galvanic coupling, i.e. a direct conduction path for the current, for providing power along the entire length of the elevator shaft.

Various other advantages will become apparent to the skilled person based on the following detailed description.

The expression "plurality" refers herein to any positive integer starting from 2, for example, 2, 3 or 4.

The terms "first" and "second" do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

The exemplary embodiments of the invention presented herein are not to be construed as limiting the applicability of the appended claims. The verb "to comprise" is used herein as an open limitation that does not exclude the presence of also unrecited features. The features recited in the dependent claims may be freely combined with each other, unless explicitly stated otherwise.

The novel features believed characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Drawings

Embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.

Fig. 1 schematically illustrates an elevator according to an embodiment of the invention.

Fig. 2A and 2B schematically illustrate an elevator car according to an embodiment of the invention.

Fig. 2C and 2D schematically illustrate an elevator according to an embodiment of the invention.

Fig. 3 schematically illustrates an elevator car according to an embodiment of the invention.

Fig. 4 schematically illustrates a wireless power transfer apparatus according to an embodiment of the present invention.

Fig. 5 schematically illustrates a wireless power transfer apparatus according to an embodiment of the present invention.

Fig. 6A and 6B schematically illustrate a wireless power transfer apparatus according to an embodiment of the present invention.

Fig. 7A and 7B schematically illustrate a wireless power transfer apparatus according to an embodiment of the present invention.

Fig. 7C and 7D schematically illustrate a three-phase wireless power transfer apparatus according to an embodiment of the present invention.

Fig. 8A and 8B schematically illustrate a linear motor of an elevator according to an embodiment of the present invention.

Fig. 9A and 9B schematically illustrate a wireless power transfer apparatus according to an embodiment of the present invention.

Detailed Description

Fig. 1 schematically illustrates an elevator 100 according to an embodiment of the invention. The elevator 100 may include at least one or more elevator cars 110 moving in a hoistway 130 or elevator shaft 130. One or more elevator cars 110 may include a first electric drive 111, such as a frequency converter or inverter, and/or a first energy store 112, such as one or more batteries, shown with dashed lines indicating the alternatives of this feature. The first electric drive 111 can be used to operate a mover 240, which is arranged to the elevator car 110 in order to move the car 110 along the elevator shaft 130 in the case of a linear motor based elevator 100. Other electrically powered devices, such as lighting, doors, user interfaces, emergency rescue equipment, etc., may also be present in the elevator car 110. The first electric drive 111 or another electric drive, such as an inverter or a rectifier, can be used to operate one or several of the other devices of the elevator car 110. The first energy storage 112 may preferably be electrically coupled to the first electric drive 111, for example to an intermediate circuit of the electric drive 111, for providing electric power to the first electric drive 111 and/or for storing electric energy provided by the first electric drive 111 or a further electric drive or other power source. When the elevator car 110 is in a position other than the first position 250 (described in more detail with reference to fig. 2A-2D), the first energy store 112 may advantageously be used to provide power to electrical equipment included in the elevator car 110.

Preferably, at least two landing floors 120 are included in the elevator 100. The landing floor 120 can include a landing floor door in an elevator shaft 130. Doors may also be included in the elevator car 110. Although there are two horizontally separated groups or "columns" of landing floors 120 shown in fig. 1, there may be only one or more than two, e.g., three, columns as in a conventional elevator. It should be noted that although fig. 1 schematically illustrates a multi-car elevator according to an embodiment of the invention, the elevator 100 may also be a conventional elevator with a hoisting machine and hoisting ropes of sufficient strength, only one elevator car 110 being configured to move in the elevator shaft and serve the landing floor 120.

With respect to the elevator shaft 130, it may be such as to define a substantially enclosed volume in which the elevator car 110 is adapted and configured to move. The wall may for example be made of concrete, metal or at least partly glass or any combination thereof. The elevator shaft 130 herein refers to essentially any structure or path along which the elevator car 110 is configured to move.

As can be seen in fig. 1, with respect to the multi-car elevator 100, the elevator car 110 or cars 110 can move vertically and/or horizontally along the elevator shaft 130, depending on the direction of the stator beams 140, 144. According to embodiments similar in this regard to the embodiment in fig. 1, the elevator car 110 or cars 110 may be configured to move along several vertical stator beams 140 and/or horizontal stator beams 144 (e.g., such as two beams in fig. 1). Preferably, the stator beams 140, 144 can be part of a linear motor of the elevator 100 used to move the elevator car 110 or cars 110 in the elevator hoistway 130. The stator beams 140, 144 may preferably be arranged in a fixed manner (i.e. in a stationary manner with respect to the elevator shaft 130), e.g. to the wall of the shaft, by means of fastening elements 148.

Fig. 2A schematically illustrates an embodiment of the present invention. The cross-sectional side view illustrates the elevator car 110. The elevator car 110 may be configured to move with the hoisting ropes 230 in conjunction with a motor or by a linear motor comprising at least one mover 240 and, as shown in fig. 2A, a stator in the stator beam 140 (in this case, the vertical stator beam 140). In the case of a linear motor, the at least one mover 240 is configured to electromagnetically engage with a stator included in the stator beam 140 of the linear motor for moving the elevator car 110 in the shaft 130. There may be one or preferably a plurality of stators included in the stator beam 140. The lift cords 230 and linear motor have been illustrated in fig. 2A and 2B using dashed lines indicating that they are optional features, such that embodiments in accordance with the present invention do not necessarily require the use of both of them at the same time.

The stator beam 140 may be attached to the elevator shaft 130 by a fastening element 148, for example, to a wall 260 of the elevator shaft 130. One or more stators may be included in the stator beam 140. The elevator 100 also comprises at least one primary winding unit 210 arranged in a fixed manner to the elevator shaft 130, such as to a wall 260 or structure of the elevator shaft 130 at the first location 250. The elevator car 110 also comprises at least one secondary winding unit 220, which is attached to the elevator car 110. There may be only one or more secondary winding units 220 in each elevator car 110, if any. The primary winding unit 210 and the secondary winding unit 220 are arranged such that there is a gap 215, i.e. an empty space, between them for enabling at least one secondary winding unit 220 to move relative to at least one primary winding during movement of the elevator car 110, said winding units 210, 220 being adapted to form an inductive coupling between said winding units 210, 220 for wireless power transfer between said winding units 210, 220 whenever the elevator car 130 is positioned, such as when said winding units 210, 220 are at a corresponding position, i.e. at a first position 250 in the direction of movement of the elevator car 110 (in this particular case, the vertical direction 225A).

Preferably, there may be several first locations 250 that are arranged to the elevator shaft 130 and thus serve as power transfer locations or "charging locations" for the elevator car 110. According to various embodiments of the invention, the first locations 250 are separated from each other by a distance such that wireless power transfer to the elevator car 110 is possible only in certain locations relative to the path along which the elevator car 110 is configured to move with the elevator shaft 130. The first location 250 can be, for example, the lowest and highest locations of each landing floor 120 and/or elevator car 110 disposed in the vertical direction 225A. In the case of a multi-car elevator, the elevator car 110 may be configured to move at least in two perpendicular directions or at least in two directions separated by an angle different from 0 or 180 degrees, and the first position 250 and thus the first winding unit 210 may be arranged at a corner position where the elevator car 110 changes direction or at any other position where the elevator car 110 is configured to stop e.g. by means of a brake.

The winding unit 210, 220 includes at least windings, i.e., a primary winding of the primary winding unit 210 and a secondary winding of the secondary winding unit 220. Preferably, the winding unit 210, 220 may comprise a coil or a plurality of coils, a magnetic core (such as a magnetic core made of at least ferromagnetic material) for forming a magnetic circuit and guiding a magnetic field between the primary winding and the secondary winding when the winding units 210, 220 are in corresponding positions with respect to each other (such as the position shown in fig. 2A). There may also be a second energy store 270 arranged electrically coupled with the primary winding unit 210. The second energy store 270 may be, for example, a battery or batteries or a capacitor. The second energy store 270 may operate as a "buffer" at the first location or "charging station" to minimize the instantaneous power and current peaks due to high power transfer at the charging station.

Whenever the elevator car 110 is at a corresponding position, i.e. with the primary winding unit 220 and the secondary winding unit 210 at corresponding positions, i.e. at the first position 250, for establishing a suitable inductive coupling, e.g. by means of a magnetic circuit having a ferromagnetic material as a magnetic core. In this case, the gap 215 may be configured to reside between the magnetic core of the secondary winding unit 220 and the magnetic core of the primary winding unit 210, such as between magnetic teeth around which a winding or coil is wound or wound.

Fig. 2B schematically illustrates an embodiment of the present invention. The cross-sectional view illustrates the elevator car 110 looking down from above. It can be seen that both the elevator car 110 and the landing floor 120 can include doors 122, 225. The elevator car 110 may be configured to move with the hoisting ropes 230 in conjunction with a motor or by a linear motor comprising at least one mover 240, and as shown in fig. 2B, a vertical stator beam 140. The at least one mover 240 is configured to electromagnetically engage with the stators of the stator beam 140 for movement along the stator beam 140 for moving the elevator car 110 in the shaft 130. The hoisting ropes 230 and the linear motor have been shown by using dashed lines indicating that they are optional features, so that two of them are not necessarily required according to embodiments of the invention.

As can be seen in fig. 2B, the primary winding 210 and the secondary winding 220 are advantageously arranged aligned with respect to each other in a direction perpendicular to the direction of movement of the elevator car 110 (i.e., in this case, with respect to the horizontal direction 225B). In this way, wireless power transfer is available whenever the elevator car 110 is in the first position 250 with respect to the vertical direction 225A, because the winding units 210, 220 are always in corresponding positions in the horizontal direction.

The mover 240 according to the embodiment in fig. 2B is U-shaped, but may also be e.g. C-shaped, in which case stators may be arranged on each side of the stator beam 140 for establishing an electromagnetic engagement between the mover 240 and the stators of the stator beam 140 for moving the elevator car along the stator beam 140.

Fig. 2C and 2D also highly schematically illustrate an elevator 100 according to various embodiments of the invention. One or several elevator cars 110 may be used in an elevator shaft 130 for use as landing floors 120. The elevator car 110 or cars 110 may be moved by hoisting ropes 230 or a linear motor comprising a mover 240 and a stator. Preferably, the primary winding units 210 may be arranged remotely with respect to each other at the first location 250 or at the power transfer location 250 or the charging location 250. "remote from each other" refers herein to the fact that the primary winding units 210 are separated from each other by a distance that requires them to form a discontinuous set of windings in the elevator shaft 130, thereby forming a "charging station" within the elevator shaft 130. The primary winding unit 250 can preferably also be electrically separated and thus controlled by a separate electric drive. The distance between two consecutive primary winding units 210 may be at least such that the primary winding unit 210 itself cannot be used to move the elevator car 110 or to provide power to the elevator car 110 continuously along the entire length of the elevator shaft 130. For example, the distance between two consecutive primary winding units 210 may be at least one meter. The benefit of arranging the primary winding unit 210 at the first position 250 (advantageously at such a position where the elevator car 110 is stopped during normal operation while serving the landing floor 120 in a normal manner) enables wireless power transfer between the primary winding 210 and the secondary winding 220 whenever the elevator car 110 has stopped at the first position 250. The highest and lowest points of the elevator shaft 130 in the direction of movement of the elevator car 110 may also be the first position 250. The wirelessly transmitted power is then used directly in the elevator car 110 or stored in an energy storage 112 of the elevator car 110, for example.

According to various embodiments of the invention utilizing a linear motor, one or more of the hoisting ropes 230 and running any electrical cables within the elevator shaft 130 for providing electrical power to the elevator car 110 have been omitted. Power is provided wirelessly at the first location 250 by transferring power, which is then stored to the first energy storage 112 of the elevator car 110. However, there may be other locations and means for powering the first energy store 112 of the elevator car 110 in addition to the wireless power transfer at the first location 250.

Fig. 3 schematically illustrates an elevator car 110 according to an embodiment of the invention. The elevator car 110 is configured to be moved by a linear motor comprising two movers 240 arranged to the rear of the elevator car 110. The elevator 100 in fig. 3 includes vertical stator beams 140 and horizontal stator beams 144. The primary winding 210 and the secondary winding 220 are disposed to the rear of the elevator car 110. However, it should be understood that in various embodiments the positions of the primary winding unit 210 and the secondary winding unit 220 are fixed with respect to the position of the components of the linear motor, but may be arranged to different sides of the elevator car 110 with respect to the components of the linear motor.

Fig. 4 schematically illustrates a wireless energy transfer device according to an embodiment of the invention. The primary winding unit 210 includes a primary winding 41 such as a coil and a primary magnetic core 415. The secondary winding unit 220 includes a secondary winding 42 such as a coil and a second magnetic core 425. Between the magnetic cores 415, 425 there is a gap 215 that enables the secondary winding unit 220 to move relative to the primary winding unit 210 and also enables said winding units 210, 220 to form a suitable magnetic circuit, inductively coupling said windings 41, 42 with each other whenever the winding units 210, 220 are at the corresponding positions. Movement of secondary winding unit 220 relative to primary winding unit 210 is illustrated in fig. 4 by double-headed arrow 435.

Fig. 5 schematically illustrates a wireless energy transfer device according to an embodiment of the invention. The primary winding unit 210 includes a primary winding 410 and a primary magnetic core 415. The primary magnetic core 415 comprises a primary tooth 417, preferably made of the same ferromagnetic material as the ferromagnetic material of the magnetic core of the primary winding unit 210. The primary winding 41 may be wound around such a primary tooth 417 as shown in fig. 5, where there is only one primary winding 41 shown in a cross-sectional side view in fig. 5. Secondary winding unit 220 includes secondary winding 42 and secondary core 425. Secondary core 425 includes a secondary tooth 427 preferably made of the same ferromagnetic material as that of the core of secondary winding unit 210. Secondary winding 42 may be wound around secondary teeth 247 as shown in fig. 5, which is shown in cross-sectional side view in fig. 5 with only one secondary winding 41.

According to various embodiments of the present invention, one or several primary windings and one or several secondary windings may be included in the primary winding unit 210 and the secondary winding unit 220, respectively. Between the magnetic cores 415, 425 there is a gap 215 that enables the secondary winding unit 220 to move relative to the primary winding unit 210 and also enables said winding units 210, 220 to form a suitable magnetic circuit, thereby inductively coupling said windings 41, 22 with each other whenever the winding units 210, 220 are at the corresponding positions. In the corresponding position, i.e. in the first position 250, the gap 215 is advantageously located between two teeth: a primary tine 417 and a secondary tine 427. Movement of secondary winding unit 220 relative to primary winding unit 210 is illustrated in fig. 5 by double-headed arrow 435.

When the primary winding unit 210 and the secondary winding unit 220 are at corresponding positions and inductive coupling is formed by exciting at least one of the primary winding 210 and the secondary winding 220, an air gap included in a magnetic circuit formed thereby has a length of at least two gaps 215. The length of each of the gaps 215 may preferably be the same relative to the other gaps, however they may also vary between different windings 41, 42 or teeth 417, 427.

Fig. 6A schematically illustrates a perspective view of a wireless power transfer device according to an embodiment of the invention. Fig. 6B illustrates a cross-sectional side view of the same embodiment as in fig. 6A. Each of the primary windings 41A to 41C is wound around the primary magnetic tooth 417. There is a gap 215 between the primary winding element 210 and the secondary winding element 220 to enable the secondary winding element 220 to move relative to the primary winding element 220 as shown by double-headed arrow 435. According to the embodiment illustrated in fig. 6A and 6B, the windings are referred to as non-overlapping windings. Each winding (primary or secondary) has been wound such that there is only one winding around one magnetic tooth 417, 427.

Fig. 7A schematically illustrates a perspective view of a wireless power transfer apparatus according to an embodiment of the present invention. Fig. 7B illustrates a cross-sectional side view of the same embodiment as in fig. 7A. In this embodiment, the windings are referred to as overlapping windings. This means that more than one winding or coil is wound around one magnetic tooth 417, 427. By overlapping windings, the windings do not have to be positioned precisely relative to each other in order to establish a proper inductive coupling for wireless energy transfer as in the case of non-overlapping windings, which require a more precise positioning of the units 210, 220. From a power transfer perspective, overlapping windings provide flexibility in positioning the secondary winding facing the primary winding without significantly affecting the operation of the magnetic circuit. Overlapping windings alleviate the challenge of accurate positioning between the primary and secondary winding elements in wireless power transfer. It better allows power transfer over the entire landing floor area (e.g., within 100 mm from the landing floor level), and thus the charging time of the energy storage 112 included in the elevator car 110 can be increased and not disturbed in case of re-leveling the elevator car 110.

Fig. 7C and 7D further schematically illustrate wireless power transfer devices utilizing overlapping windings, in accordance with embodiments of the present invention. In these particular cases, primary winding unit 210 and secondary winding unit 220 comprise three-phase windings, the phases of which are labeled A, B and C. Still further, "+ a", "+ B", and "+ C" refer to a first direction of current flow in the corresponding phase winding, while "-a", "— B", and "-C" refer to a second direction of current flow in the corresponding phase winding, e.g., + a means that current flow in the phase a winding is flowing out of the observer and into the surface of the figure, and-a means that current flow is flowing to the observer and out of the surface of the figure.

In fig. 7C, the secondary winding unit 220 is at a precise location 701 where the secondary tine 427 substantially faces the primary tine 417. The precise location 701 is an optimal location for wireless power transfer between the secondary winding element 220 and the primary winding element 210. Fig. 7D illustrates the same or at least a similar embodiment as in fig. 7C, however, in this case the secondary winding unit 220 is at an inaccurate position 702 relative to the primary winding unit 210, at which the secondary and primary tines 427, 417 do not face each other exactly. However, by utilizing overlapping windings, wireless power transfer between the secondary winding unit 220 and the primary winding unit 210 is enhanced relative to embodiments having non-overlapping windings at non-precise locations (such as fig. 6A and 6B). By overlapping windings, wireless power transfer is possible at any position of the secondary winding unit 220 relative to the primary winding unit 210 whenever the secondary winding unit 220 and the primary winding unit 210 are located at the first position 250 of the elevator, and is enhanced relative to embodiments with non-overlapping windings. If a part of the wireless power transfer is arranged at said landing floor 120, the use of overlapping windings facilitates wireless power transfer, e.g. during releveling of the elevator car 110 at the landing floor 120.

According to various embodiments of the present invention, the primary winding unit 210 may be a part of a stator of a linear motor. For example, the stator may be composed of separate parts with windings. Thus, according to embodiments of the invention, the separate part, which may preferably be independently controllable with respect to other parts of the stator, may be operated as a primary winding. According to an embodiment of the present invention, the windings of the mover 240 may be used as secondary windings, if any. Still further, the separate windings configured to the elevator car 100 according to embodiments of the invention may serve as secondary windings in addition to the windings configured to electromagnetically engage with the windings of the stator for moving the mover along the stator, thus moving the elevator car 110.

Fig. 8A schematically illustrates a mover 240 having a C-shape, the mover 240 comprising electromagnetic component units 810, such as at least windings or one or more coils, and optionally a magnetic core with magnetic teeth, and/or permanent magnets; and a stator beam 140 including a stator 800 according to an embodiment of the present invention. It should be understood that one or several electromagnetic component units 810 and/or stators 800 may be included in the mover 240 and the stator beam 140, respectively. The electromagnetic component unit 810 is adapted to face the stator 800 so as to form an electromagnetic engagement between the electromagnetic component unit 810 and the stator 800 or at least to enable an electromagnetic engagement therebetween for moving the mover 240 relative to the stator beam 140. This requires controlling the current injected into the electromagnetic component unit 810 of the mover 240 in order to adjust the gap between the electromagnetic component unit 810 and the stator 800 when the elevator car 110 moves along the stator beam 140 and/or when the elevator car 110 stops at the landing floor 120. The current injected into the electromagnetic component unit 810 may be performed and controlled by one electric drive 111 or several electric drives 111A, 111B of the mover 240, such as one or more frequency converters or one or more inverters. Separate drivers 111A, 111B may be used to provide power to the different windings 81.

Fig. 8B further illustrates, from a cross-sectional side view, an electromagnetic component unit 810 adapted to face a stator 800. There is a gap 815 between the electromagnetic unit 810 and the stator 800 for enabling the mover 240 to move with respect to the stator beam 140. The stator beams 140 include (i.e., in the sense that they do not include electromagnetic components (such as windings or coils) arranged along the entire stator beam 140 and are configured to generate a magnetic field for moving the mover 240 along the stator beam 140) one or several stators 800 that are primarily passive. The one or more stators 800 and their teeth are preferably made of ferromagnetic material. The mover 240, on the other hand, comprises at least windings 81 or coils, and optionally permanent magnets and magnetic cores with magnetic teeth, for generating a magnetic field to engage with one or more stators 800 for moving the mover 240 along the stator beams 140.

In some embodiments, at least the magnetic core of primary winding unit 210 or secondary winding unit 220, or both, is made of electrical steel.

Fig. 9A and 9B illustrate some embodiments according to the invention. The primary winding unit 210 or at least the primary windings 41, 41A to 41C may be arranged to the stator beam 140 at one or more first locations 250 arranged distant from each other. The primary windings 41, 41A to 41C may be operated by a second electric driver 825 or a plurality of drivers 825. There may also be a "buffer battery", i.e. a second energy storage electrically coupled with one or more second electric drives 825. In fig. 9A, the primary windings 41, 41A to 41C have been arranged in a non-overlapping manner as described with reference to fig. 6A and 6B. In fig. 9B, one or more electromagnetic assembly units 810, in which the primary windings 41, 41A to 41C have been arranged in an overlapping manner as described with reference to fig. 7A and 7B, may be directly used as the secondary windings 42, 42A to 42C. They may also be arranged in a non-overlapping or overlapping manner. Preferably, the primary winding and the secondary winding may be arranged in a similar manner with respect to each other. Advantageously, the embodiment according to fig. 9A to 9B does not need to have a separate secondary winding.

In the embodiment according to fig. 9A or 9B or in a similar embodiment, the primary winding unit 210 may preferably be provided with power from the main power supply of the elevator 100 (e.g. from a power distribution network). With the second energy store 270, the primary winding unit 210 and its primary windings 41, 41A to 41C may be at least partially provided with electrical energy stored in the second energy store 270, for example, for minimizing instantaneous power and current peaks due to high power transfer at the charging station (i.e. at the first location 250).

With regard to utilizing the windings 81 of the mover 240, i.e. the windings arranged to the teeth of the armature of the mover 240 as the secondary windings 42, 42A to 42C according to the invention, the secondary windings may be operated such that whenever the elevator car 110 is at the first position 250, a locking means, such as a magnet or a mechanical brake or an electromechanical brake, holds the elevator car 110 in place while the windings of the mover 240 are not energized and operate like the secondary windings of a transformer, receiving electrical energy by magnetic induction. On the other hand, the windings of the mover 240 may be excited by the first electric drive 111 in the elevator car 110, and the voltage levels and voltage phases as well as the characteristics of the currents in the primary windings 41, 41A to 41C may be controlled in order to transfer electric power to the secondary windings 42, 42A to 42C, i.e. in this particular case the windings of the mover 240.

The length of the gap 215 (i.e., in the direction of the double-headed arrow associated with reference numeral 215) may preferably be 0 to 10 millimeters. According to embodiments comprising in particular separate primary winding element 210 and secondary winding element 220, the length of the gap 215 may preferably be from 5 to 10 mm, thus always allowing the secondary winding element 220 to move with respect to the primary winding element 210, however, the length of the gap 215 may also be less than 5 mm. According to embodiments including the primary winding unit 210 and the secondary winding unit 220 integrated into portions of the linear motor (i.e., integrated into the mover 240 and the one or more stators 800), the length of the gap 215 may preferably be from 0 to 2.5 millimeters. A zero length refers e.g. to a situation where the elevator car 110 is located at a landing floor 120 and the levitation of the mover 240 relative to one or more stators 800 has been stopped by bringing the mover 240 into contact with at least one stator 800. In this case, the length of the gap 215 may be zero, however, once the mover 240 recovers before floating on the one or more stators 800 on the moving elevator car 110, the length of the gap 215 becomes greater than zero, and preferably up to 2.5 mm, thereby allowing the secondary winding unit 220 to move relative to the primary winding unit 210.

According to one or more embodiments, the primary winding unit 210 may comprise a switching unit coupled to the primary winding 41, the switching unit having an input for receiving a power supply control signal from the elevator control unit, and the switching unit being configured to provide the AC voltage to the primary winding 41 based on the power supply control signal.

According to one or more embodiments, the elevator 100 may comprise an elevator control unit for controlling movement of the elevator car and a position sensor adapted to sense the position of the elevator car 110. The position sensor may preferably be connected to the elevator control unit. The elevator control unit may be configured to form the power supply control signal when the position sensor indicates that the elevator car has reached or is about to reach the desired charging position. The primary winding unit may include a switching unit coupled to the primary winding of the primary winding unit, the switching unit having an input for receiving a power supply control signal from the elevator control unit. The switching unit may be configured to provide the AC voltage to the primary winding based on the power supply control signal.

The switching unit may comprise one or more controllable switches, such as one or more relays, an IGBT (insulated gate bipolar transistor) transistor, one or more MOSFET (metal oxide semiconductor field effect transistor) transistors, etc.

According to an embodiment, the expected charging position may be recorded into the memory of the elevator control unit. The first energy storage 112 may comprise or may be coupled to a determination device for determining the state of charge of the first energy storage 112. The first energy storage 112 may be connected to the elevator control unit via a data link, preferably a wireless link or data line of a travelling cable, for indicating the charging requirement of the first energy storage 112. The elevator control unit may be configured to command the elevator car 110 to stop at the desired charging position in response to receiving a charging demand (e.g., a signal indicating a charging demand or an indication of a low state of charge of the first energy storage 112).

The specific examples provided in the description given above should not be construed as limiting the applicability and/or interpretation of the appended claims. The example lists and groups provided in the description given above are not exhaustive unless explicitly stated otherwise.

Claims (15)

1. A wireless power transfer device (200) for an elevator car (110) of an elevator (100), the wireless power transfer device (200) comprising:

-primary winding units (210) arranged relative to each other at a first position (250) of an elevator shaft (130), the elevator car (110) being configured to move along the elevator shaft (130), wherein each primary winding unit (210) comprises primary windings (41; 41A to 41C),

at least one secondary winding unit (220) arranged to the elevator car (110), wherein each of the at least one secondary winding unit (220) comprises a secondary winding (42; 42A-42C),

wherein each of the primary winding units (210) and each of the at least one secondary winding unit (220) are arranged such that a gap (215) exists between the winding units (210, 220), so that the at least one secondary winding element (220) is movable relative to the primary winding element (210), and each time one of the at least one secondary winding unit (220) comprising the windings (41; 41A-41C; 42; 42A-42C) and one of the primary winding units (210) are arranged to face each other at one of the first positions (250) at which the one of the primary winding units (210) is arranged, an inductive coupling is established between the secondary winding (42; 42A-42C) and the primary winding (41; 41A-41C).

2. The wireless power transfer device (200) of claim 1, wherein the device (200) comprises a first energy storage (112), the first energy storage (112) being mounted to the elevator car (110) and coupled to the secondary winding unit (220).

3. The wireless power transfer device (200) of claim 1 or 2, wherein the primary winding unit (210) comprises a plurality of ferromagnetic teeth (217), the primary winding (41; 41A-41C) being wound around at least one ferromagnetic tooth of the plurality of ferromagnetic teeth.

4. The wireless power transfer device (200) of any preceding claim, wherein the at least one secondary winding unit (220) comprises a plurality of ferromagnetic teeth (227), the secondary winding (42; 42A-42C) being wound around at least one of the plurality of ferromagnetic teeth.

5. The wireless power transfer device (200) of any preceding claim, wherein at least one of the primary winding (41; 41A-41C) and the secondary winding (42; 42A-42C) is an overlapping winding.

6. The wireless power transfer device (200) according to any of the preceding claims, wherein the primary winding (41; 41A-41C) is arranged to a tooth of a stator (800), the stator (800) being comprised in a stator beam (140) of a linear motor of the elevator (100).

7. The wireless power transfer device (200) according to any of the preceding claims, wherein the at least one secondary winding (42; 42A-42C) is arranged to a tooth of an armature of a mover (240) of a linear motor of the elevator (100).

8. The wireless power transfer device (200) of any preceding claim, wherein the remotely arranged primary winding units (210) are electrically separated from each other and have a distance of at least one meter between two consecutive primary winding units (210).

9. The wireless power transfer device (200) of any preceding claim, wherein each of the primary winding units (210) comprises a second energy storage (270) for minimizing instantaneous power and current peaks.

10. Elevator (100), characterized in that the elevator (100) comprises an elevator shaft (130), along which elevator shaft an elevator car (110) of the elevator (100) is configured to move, wherein the elevator (100) further comprises: at least two primary winding units (210) arranged to at least two remotely arranged first locations (250) of the elevator shaft (130); and at least one secondary winding unit (220) arranged to the elevator car (110), wherein each of the primary winding units (210) comprises a primary winding (41; 41A to 41C) and each of the at least one secondary winding units (210) comprises a secondary winding (42; 42A to 42C), and wherein the winding units (210, 220) are arranged such that there is a gap (215) between them in order to enable the at least one secondary winding unit (220) to move relative to the primary winding unit (210) during movement of the elevator car (110), wherein the winding units (210, 220) are adapted to form an inductive coupling between the windings (41; 41A to 41C; 42; 42A to 42C) each time the elevator car (110) is located at one of at least one first position (250), for wireless power transfer between the windings (41; 41A-41C; 42; 42A-42C).

11. The elevator (100) of claim 10, wherein the primary winding elements (210) are electrically separated with respect to each other and have a distance of at least one meter between two consecutive primary winding elements (210).

12. The elevator (100) according to claim 10 or 11, wherein the primary winding (41; 41A-41C) and the secondary winding (42; 42A-42C) are overlapping windings.

13. Elevator (100) according to any of claims 10-12, wherein the primary winding (41; 41A-41C) is arranged to a stator (800), which stator (800) is comprised in a stator beam (140) of a linear motor of the elevator (100).

14. Elevator (100) according to any of claims 10-13, wherein the secondary winding (42; 42A-42C) is arranged to a mover (240) of a linear motor of the elevator (100).

15. The elevator (100) according to any of claims 10 to 14, wherein each of the primary winding units (210) comprises a second energy storage (270) for minimizing instantaneous power and current peaks.