WO2019153254A1

WO2019153254A1 - System and method for wireless power transfer

Info

Publication number: WO2019153254A1
Application number: PCT/CN2018/076017
Authority: WO
Inventors: Xu Chen; Xiaobo Yang; Tinho LI
Original assignee: Abb Schweiz Ag
Priority date: 2018-02-09
Filing date: 2018-02-09
Publication date: 2019-08-15

Abstract

Embodiments of present disclosure provide a system and a method for wireless power transfer (WPT). The system comprising: a first coil arranged in a first shielding housing and configured to, when applied with a second current, generate a magnetic field; a second coil arranged in a second shielding housing and configured to, in response to the generated the magnetic field, generate a first current for charging a target device, wherein the first and second shielding housings are adapted to be magnetized by the magnetic field to generate an electromagnetic force to cause the first and second coils to be aligned.

Description

SYSTEM AND METHOD FOR WIRELESS POWER TRANSFER

FIELD

Embodiments of present disclosure generally relate to power transfer, and more specifically, to a system and a method for wireless power transfer (WPT) .

BACKGROUND

Wireless power transfer (WPT) has a wide market prospect due to the increasing market share of electric vehicles and the strong desire of charging consumer electronics without wiring. A huge amount of researches and commercial efforts have been done to realize the wireless power transfer. But one of the major prob lems of WPT is that the transmitter and receiving coils need to be well aligned before wireless charging, otherwise the transferring power and/or transferring efficiency would be reduced.

Methods for condition monitoring have been studied for a long time. Generally, most of the methods require detecting the relative position of the transmitting coil and receiving coil by using sensors, then changing the position of transmitting coil or receiving coil by using auxiliary motor or relying on the manual correction of car operator and determining whether the threshold of alignment is fulfilled.

Several kinds of sensor, including camera, different auxiliary sensor coils and haptic module may be required for WPT alignment. However, on one hand, system costs are increased by the use of sensors and on the other hand, the sensors may be less reliable due to environmental factors, for example, an under-chassis camera is obscured by dust.

Even if the misalignment information is successfully obtained, the common misalignment correction solutions are still unsatisfied, because it is difficult to automatically and accurate adjust the position of transmitter or receiving coil. For a car operator, a correction of the lateral misalignment is problematic on a parking lot or a charging station.

SUMMARY

Embodiments of the present disclosure provide a system and a method for wireless power transfer (WPT) .

In first aspect, a system for WPT is provided. The system comprising: a first coil arranged in a first shielding housing, a second coil arranged in a second shielding housing and configured to generate a first current for charging a target device, wherein at least one of the first and second coil is configured to, when applied with a second current, generate a magnetic field, wherein the first and second shielding housings are adapted to be magnetized by the magnetic field to generate an electromagnetic force to cause the first and second coils to be attracted by and aligned with each other.

Conventional WPT systems comprising a plurality of sensors for determining if the transmit coil and receive coil is aligned with each other. The plurality of sensors are usually mounted on the front, rear, or bottom of the vehicle. The measurement results are sensitive to the environment, such as dust, dirt, rain and light and thus are error-prone. In addition, the high system costs associated with using the plurality of sensors. Compared with the traditional WPT systems, embodiments of present disclosure omit the sensors. By enabling the energized coils to attract one another, the reliability of the degree of coil alignment can be enhanced. Moreover, the charging performance can be improved. In addition, by omitting sensors, the cost can be significantly reduced.

In some embodiments, the system further comprising: an enclosure for accommodating the first shielding housing, wherein the first shielding housing is movable in the enclosure. In this way, the first coil arranged in the first shielding housing is movable as well, in particular by attractive forces generated by the magnetic field. This structure enables the first coil to be aligned toward the second coil while avoiding unexpected manual adjustment of the position of the first coil.

In some embodiments, the enclosure is arranged below or on the ground. In such embodiments, the transmit coil can be arranged without occupying the space of parking lot, thereby achieving high flexibility in deploying the system.

In some embodiments, the system further comprising: a sliding mechanism operable to slide the first shielding housing within the enclosure in response to electromagnetic force. In this way, due to the attractive force between the energized coils, the coils can be brought closer to each other by means of a sliding mechanism. As a result, the coils can be automatically aligned with each other without using an additional motor as in the known solutions. The additional motor requests extra power and space resource, this is not ideal for WPT system.

In some embodiments, the enclosure comprises a lubricant layer between the first shielding housing and the enclosure to facilitate the movement of the first shielding housing within the enclosure.

In some embodiments, the first shielding housing is adapted to, when applied with the electromagnetic force, suspend within the enclosure.

In some embodiments, the first shielding housing and the second shielding housing are made of magnetic material. In this way, both the first and second coils can attract each other due to the current generated by the magnetized shielding housing, thereby achieving alignment in a more effective and flexible way.

In some embodiments, wherein the second coil is mounted within the target device so that the second coil, once it reaches the charging position, can be quickly matched to the transmit coil without any other manual adjustment.

In some embodiments, the second coil is detachably coupled to the target device. In this way, the receive coil does not have to be provided in the vehicle but can be connected to the vehicle only when the vehicle reaches the charging position. As a result, the flexibility of the system configuration is high while the manufacturing cost of the charging vehicle can be maintained relatively low.

In some embodiments, the target device is a vehicle.

In some embodiments, the target device is a consumer electronics product.

In some embodiments, the system further comprising: a controller configured to determine a difference a first power associated with the second current and a second power associated with the first current; and in response to determining that the difference exceeds a threshold, cease supplying the second current. In this way, the charging performance can be monitored by comparing the power associated with the current of the transmitting and receiving coils. As the charging performance reflects whether the coils are aligned for the best charging effect, rather than just the physical alignment of the coils as disclosed in the known solutions.

In some embodiments, the controller is further configured to monitor the number of times of ceasing the supply of the second current is ceased; and report an error in response to determining that the number of times exceeds a threshold number.

In some embodiments, the controller is further configured to resume supplying the second current in response to determining that the difference falls below the threshold.

In second aspect, a method for WPT is provided. The method comprising: supplying a second current to at least one of a first coil and a second coil to generate a magnetic field, the first coil arranged in a first shielding housing, the second coil arranged in a second shielding housing and configured to generate a first current for charging a target device, wherein the first and second shielding housings are adapted to be magnetized by the magnetic field to generate an electromagnetic force to cause the first and second coils to be attracted by and aligned with each other.

In some embodiments, the method further comprising: determining a difference a first a charging power associated with the second current and a second power associated with the first current; and in response to determining that the difference exceeds a threshold, ceasing supplying the second current.

In some embodiments, the method further comprising: resuming supplying the second current in response to determining that the difference falls below the threshold.

In third aspect, a computer program product is provided. The computer program product being tangibly stored on a computer readable storage medium and comprising instructions which, when executed on at least one processor, cause the at least one processor to perform the method. The method comprising: supplying a second current to a first coil to generate a magnetic field, the first coil arranged in a first shielding housing, a second coil arranged in a second shielding housing and configured to, in response to the generated the magnetic field, generate a first current for charging a target device, wherein the first and second shielding housings are adapted to be magnetized by the magnetic field to generate an electromagnetic force to cause the first and second coils to be aligned.

In fourth aspect, a computer-readable medium storing machine-executable instructions is provided. The machine-executable instructions, when executed, enabling the machine to execute the method. The method comprising: supplying a second current to a first coil to generate a magnetic field, the first coil arranged in a first shielding housing, a second coil arranged in a second shielding housing and configured to, in response to the generated the magnetic field, generate a first current for charging a target device, wherein the first and second shielding housings are adapted to be magnetized by the magnetic field to generate an electromagnetic force to cause the first and second coils to be aligned.

DESCRIPTION OF DRAWINGS

Drawings described herein are provided to further explain the present disclosure and constitute a part of the present disclosure. The example embodiments of the disclosure and the explanation thereof are used to explain the present disclosure, rather than to limit the present disclosure improperly.

FIG. 1 illustrates a schematic diagram of a system for WPT, in accordance with embodiments of the present disclosure;

FIG. 2 illustrates a schematic diagram of a system for WPT used in a vehicle charging station, in accordance with embodiments of the present disclosure;

FIG. 3A illustrates a schematic diagram of a system for WPT, in accordance with embodiments of the present disclosure;

FIG. 3B illustrates a schematic diagram of a system for WPT, in accordance with embodiments of the present disclosure;

FIG. 3C illustrates a schematic diagram of a system for WPT, in accordance with embodiments of the present disclosure;

FIG. 4 illustrates a flowchart of a method for WPT, in accordance with an embodiment of the present disclosure; and

Throughout the drawings, the same or similar reference symbols are used to indicate the same or similar elements.

DETAILED DESCRIPTION OF EMBODIEMTNS

Principles of the present disclosure will now be described with reference to several example embodiments shown in the drawings. Though example embodiments of the present disclosure are illustrated in the drawings, it is to be understood that the embodiments are described only to facilitate those skilled in the art in better understanding and thereby achieving the present disclosure, rather than to limit the scope of the disclosure in any manner.

The term “comprises” or “includes” and its variants are to be read as open terms that mean “includes, but is not limited to. ” The term “or” is to be read as “and/or” unless the context clearly indicates otherwise. The term “based on” is to be read as “based at least in part on. ” The term “being operable to” is to mean a function, an action, a motion or a state can be achieved by an operation induced by a user or an external mechanism. The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment. ” The term “another embodiment” is to be read as “at least one other embodiment. ” The terms “first, ” “second, ” and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below. A definition of a term is consistent throughout the description unless the context clearly indicates otherwise.

Unless specified or limited otherwise, the terms “mounted, ” “connected, ” “supported, ” and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Furthermore, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. In the description below, like reference numerals and labels are used to describe the same, similar or corresponding parts in the figures. Other definitions, explicit and implicit, may be included below.

FIG. 1 illustrates a schematic diagram of a system 100 for wireless power transfer. As shown, the system for wireless power transfer generally includes a first coil 122 (may also referred to as transmitting coil) and a second coil 112 (may also referred to as receiving coil) . The first coil is arranged in a first shielding housing 124 and the second coil is arranged in a second shielding housing 114.

Generally, the first coil 122 may be arranged at a vehicle charging station for which may be located in a parking lot. Alternative, the first coil 122 may be arranged at charging board for the consumer electronics products. The first coil may be connected with a power grid and supplied by the power grid.

Accordingly, the second coil 112 may be arranged at a target device which needs to be charged. For example, in some embodiments, the target device may be a vehicle. Alternative, the target device may be any of the consumer electronics products including, but not limit to cell phones, laptops, desktop computers, and wearable device, etc.

The first and

second shielding housings

124, 114 both are made of magnetic material and adapted to be magnetized by a magnetic field to generate an electromagnetic force to cause the first and

second coils

122, 112 to be aligned.

In some embodiment, the first and

second shielding housings

124, 114 are made of ferfite. It is to be understood that any of suitable magnetic material may be used to form the first and

second shielding housings

124, 114. By forming the first and

second shielding housings

124, 114 of magnetic material, both the first and second coils can attract each other due to the current generated by the magnetized shielding housing, thereby achieving alignment in a more effective and flexible way.

Embodiments of the present disclosure provide a sensorless WPT system. Compared with the traditional WPT systems, embodiments of present disclosure omit the sensors. By enabling the energized coils to attract one another, the reliability of the degree of coil alignment can be enhanced. Moreover, the charging performance can be improved. In addition, by omitting sensors, the cost can be significantly reduced.

FIG. 2 illustrates a schematic diagram of a system for WPT used in a vehicle charging station. In this example, without suggesting any limitations as to the scope of the subject matter described herein, the system 100 is a vehicle charging system. In this example, the first coil 122 may be located on the parking lot and the corresponding second coil 112 may be mounted in the vehicle which is parked or to be parked in the parking lot.

As shown in FIG. 2, the vehicle 150 is parked in the parking lot and the charging station is located below the vehicle. In this example, the first coil of the system 100, along with the grid (not shown) to which the transmitting coil is connected, could be considered as a charging station. The second coil of the system 100 may be mounted in the vehicle 150 which is considered as a target device to be charged. That is, the second coil of the system 100 may be considered as a component of the vehicle. In some embodiment, the second coil of the system 100 may be also considered as an individual charging component, which may be mounted into the vehicle 150 only when the vehicle is parked in the parking lot.

As further illustrated in FIG. 2, the system 100 may include the first shielding housing 124, in which the first coil (not shown) is arranged and the second shielding houses 114, in which the second coil (not shown) is arranged. The first shielding house 124 is accommodated in an enclosure 140, which is located below the ground 143 of the parking lot. Alternatively, the enclosure 140 may be arranged on the ground. The enclosure 140 may be considered as an enclosed space which limits a range of movement for the first shielding house 124. It is to be understood that the enclosure 140 may cover the range of a parking lot for an vehicle (below or on the ground) to adapt the position of the first shielding house 124 (the first coil) to be adjusted in relative to the different mounting position of the corresponding second shielding house 114 (the second coil) on the vehicle 150. In such embodiments, the transmit coil can be arranged without occupying the space of parking lot, thereby achieving high flexibility in deploying the system.

The system 100 further includes a sliding mechanism 130, which is operable to slide the first shielding house 124, so that the first shielding housing 124 is movable in the enclosure 140. In this way, the first coil arranged in the first shielding housing is movable as well, in particular by attractive forces generated by the magnetic field. This structure enables the first coil to be aligned toward the second coil while avoiding unexpected manual adjustment of the position of the first coil.

In this example, the sliding mechanism 130 including a plurality of universal wheels arranged between the first shielding housing 124 and the upper and bottom side of the enclosure 140, respectively. It is to be understood that the sliding mechanism 130 may be any suitable type of ball-shaped component such as rolling bearing.

By using the sliding mechanism, due to attractive force between the energized coils, the coils can be brought closer to each other by means of a sliding mechanism. As a result, the coils can be automatically aligned with each other without using an additional motor as in the known solutions. The additional motor requests extra power and space resource, this is not ideal for WPT system.

In some embodiment, a lubricant layer is provided instead of the universal wheels, which facilitate the movement of the first shielding housing 124 within the enclosure 140. The lubricant layer is preferably arranged between the first shielding housing 124 and the bottom side of the enclosure 140. More preferably, the lubricant layer is provided on both upper and bottom side of the enclosure 140, which contacts the first shielding housing 124, respectively. In some embodiment, the first shielding housing 124 is adapted to suspend within the enclosure 140, for example, by applied with an electromagnetic force.

As further illustrated in FIG. 2, once the vehicle arrives in the parking lot, a charging process may be initiated. That is to say, the first coil is applied with a supply current from the grid and the alignment between the first and second coil will be performed.

FIGS. 3A-3C shows the schematic diagrams of the first and second coils in the system for WPT in three different phases. FIG. 3A shows the initial status between the first and second coils, in which the first and second coils are misaligned. FIG. 3B shows a charging process is initiated and an electromagnetic force F is generated to cause the first and second coils to be aligned. FIG. 3C shows the final status of the first and second coils i.e., the first and second coils are aligned with each other.

A charging process of the system for WPT in accordance with the present disclosure will be further detailed in junction with FIGS. 3A-3C.

Although the target device is not shown in FIGS 3A-3C, it is to be understood that the second coil 112 is coupled or mounted to the target device to be charged, while the first coil 122 is arranged at the charging station.

As shown in FIG. 3A, the first coil 122 and the second coil 112 are misaligned. For example, the first coil 122 and the second coil 112 are offset by a distance D. Once the charging process is initiated, the alignment process is also performed. During the alignment process, the offset between the first coil 122 and the second coil 112 can be corrected.

It should be noted that one of the object of the present invention is to achieve the optimal charging efficiency between the transmitting coil and the receiving coil while realizing the sensorless automatic alignment. Since it has been confirmed that the alignment of positions does not imply that optimal charging efficiency can be achieved, the term “alignment” referred to in the present disclosure is not necessarily intended to completely eliminate the positional offset between the transmitting coil and the receiving coil, but rather to provide the optimal charging efficiency through automatic alignment. It should be understood that in the case of achieving the optimal charging efficiency, there may still be an offset between the transmitting coil and the receiving coil.

The foregoing mentioned term “charging efficiency” refers to the ratio between the electric power generated by the receive coil and the electric power supplied to the transmit coil. In the ideal state, that is, there is no transfer loss between the transmit coil and the receive coil, the ratio is 1. However, in general, the electric power generated by the receive coil is slightly less than the electric power supplied to the transmit coil.

As described above, when the charging process is initiated, a second current is applied to at least one of the first and

second coils

122, 112. In this example, the second current is applied to the first coil 122. In one example, the second current may be applied to the second coil 112. In another one example, the second current may be applied to both the first and second currents. The second current may be supplied from a power network. It should be understood that the second current may be a AC or DC current. As shown in FIG. 3B, a magnetic field 200 is generated by the second current flowing the first coil 122 and the first shielding housing is magnetized by the magnetic field 200. Correspondingly, when the magnetic field 200 is generated, a first current (charging current) is generated in the second coil 112 due to an electromagnetic induction. The first current is supplied to the target device 150 to be charged.

Meanwhile, since the second shielding housing 114 is magnetized by the magnetic field 200, an induction current is generated in second coil 112, so that an electromagnetic force F is generated between the first and

second shielding housings

124, 114 to cause the first and

second coils

122, 112 to be attracted by each other. Under the electromagnetic force F, the first and

second coils

122, 112 can be aligned with one another.

As described above, for example, referring to FIG. 2, the additional sliding mechanism 130 is mounted on the first shielding housing 124. When the electromagnetic force is generated, the first shielding housing 124 and the second shielding housing 114 are attracted toward each other. The first shielding housing 124 is moved in relative to the second shielding housing 114 by means of sliding mechanism 130 to cause the first coil 122 and the second coil 112 to be aligned.

During the charging process, by way of the shielding housing, the magnetic envelope of the magnetic field 200 is concentrated between the first coil 122 and the second coil 112. Since the current intensity is essentially dependent on the strength of the magnetic field, the concentration of the electromagnetic envelope can further ensure the charging efficiency between the first coil 122 and the second coil 112.

FIG. 3C shows a final status of the alignment process in accordance with one embodiment of the present disclosure. As shown, the first coil 122 is substantially aligned with the second coil 112.

Although the foregoing embodiments only discussed the case where the sliding mechanism is provided for the first shielding housing 124, it is to be understood that the second shielding housing 114 is also provided with at least one sliding mechanism. That is, when the electromagnetic force is applied on both of the first shielding housing 124 and the second shielding housing 114, the first shielding housing 124 and the second shielding housing 114 may be moved towards each other, respectively.

In some embodiment, the charging process may be initiated by applying a second current to the second coil 112. Therefore, the magnetic field 200 is generated in the second shielding housing 114. The first shielding housing 124 is magnetized to cause the first coil 114 to response the generated magnetic field 200 and generate an induction current to cause the first and

second coils

122, 112 to be aligned accordingly.

In some embodiment, the second current (the initiate current) may be applied to both the first and second coils to cause the magnetic field 200 is generated in both the first and

second shielding housings

124, 114. The induction currents generated in both the first and

second coils

122, 112 in such a polarity that both the first and

second shielding housings

124, 114 are attracting each other cause an electromagnetic force F to be generated between the first and

second shielding housings

124, 114. Therefore, the first and

second coils

122, 112 could be aligned.

In some embodiment, the system 100 further includes a controller. The controller is configured to detecting the charging efficiency. In this example, the controller is configured to determine a difference a first power associated with the second current and a second power associated with the first current and cease supplying the second current when the difference exceeds a threshold. For example, the maximum difference may be set to 20%of first power associated with the second current. After ceasing supplying the second current, the charging process will be reactivated by injecting the second current into the first coil.

In some embodiment, if it is determined that the difference between a first power associated with the second current and a second power associated with the first current falls below the threshold, the controller is further configured to resume supplying the second current, until the charging process is finished.

In some embodiment, the controller is further configured to identify the system failure. For example, the controller is configured to monitor the number of times of ceasing the supply of the second current is ceased and report an error if it is determined that the number of times exceeds a threshold number.

By way of the example illustrated in FIGS 3A-3C, a system for wireless power transfer without extra sensor or any auxiliary motion mechanism is achieved. By using the system in accordance with the present disclosure, the system reliability can be improved while reducing the system cost. Meanwhile, the movement speed of the transmitting coil may be adjusted by control the second current, if needed. The speed control makes the alignment more smoothly and reduces the mechanic stress of the movable transmitting coil.

FIG. 4 illustrates a flowchart of a method 400 for WPT, in accordance with an embodiment of the present disclosure. In some embodiments, the method 400 may be implemented in software and/or firmware by means of, for example, the system 100.

At block 410, a second current is applied to a first coil to generate a magnetic field. As described above, a magnetic field 200 is generated by the second current flowing the first coil 122 and the first shielding housing is magnetized by the magnetic field 200. Correspondingly, when the magnetic field 200 is generated, a first current is generated in the second coil 112 due to an electromagnetic induction. The first current is supplied to the target device to be charged. Meanwhile, since the magnetic material forming the first shielding housing 124 and the second shielding housing 114 is magnetized, an electromagnetic force is generated to cause the first and second coils to be aligned.

After the first current is generated and the alignment process began, at block 420, a difference a first a charging power associated with the second current and a second power associated with the first current is determined.

At block 430, it is determined whether the difference exceeds the threshold. As described above, in one embodiment, the maximum difference may be set to 20%of first power associated with the second current. In some embodiment, if the difference does not exceed the threshold, at block 440, the second current is supplied until the charging process is finished.

In some embodiment, if the difference exceeds the threshold, at block 450, the second current is ceased.

In some embodiment, at block 460, the number of times of ceasing the supply of the second current is monitored. At block 470, if it is determined that the number of times exceeds the threshold, at block 480, an error is reported.

In this way, the charging performance can be monitored by comparing the power associated with the current of the transmitting and receiving coils. As the charging performance reflects whether the coils are aligned for the best charging effect, rather than just the physical alignment of the coils as disclosed in the known solutions.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to Fig. 4. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. On the other hand, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A system (100) for wireless power transfer (WPT) comprising:

a first coil (122) arranged in a first shielding housing (124) ;

a second coil (112) arranged in a second shielding housing (114) and configured to generate a first current for charging a target device (150) ,

wherein at least one of the first and second coil (122, 112) is configured to, when applied with a second current, generate a magnetic field (200) ,

wherein the first and second shielding housings (114, 124) are adapted to be magnetized by the magnetic field (200) to generate an electromagnetic force (F) to cause the first and second coils (122, 112) to be attracted by and aligned with each other.
The system (100) of claim 1, further comprising:

an enclosure (140) for accommodating the first shielding housing (124) , wherein the first shielding housing (124) is movable in the enclosure (140) .
The system (100) of claim 2, wherein the enclosure (140) is arranged below or on the ground (143) .
The system (100) of claim 2, further comprising:

a sliding mechanism (130) operable to slide the first shielding housing (124) within the enclosure in response to electromagnetic force (F) .
The system (100) of claim 2, wherein the enclosure (140) comprises a lubricant layer between the first shielding housing (124) and the enclosure (140) to facilitate the movement of the first shielding housing (124) within the enclosure (140) .
The system (100) of claim 2, wherein the first shielding housing (124) is adapted to, when applied with the electromagnetic force, suspend within the enclosure (140) .
The system (100) of claim 1, wherein the first shielding housing (124) and the second shielding housing (114) are made of magnetic material.
The system (100) of claim 1, wherein the second coil (112) is mounted within the target device (150) .
The system (100) of claim 1, wherein the second coil (112) is detachably coupled to the target device (150) .
The system (100) of claim 1, wherein the target device (150) is a vehicle.
The system (100) of claim 1, wherein the target device (150) is a consumer electronics product.
The system (100) of claim 1, further comprising:

a controller configured to

determine a difference a first power associated with the second current and a second power associated with the first current; and

in response to determining that the difference exceeds a threshold, cease supplying the second current.
The system (100) of claim 12, wherein the controller is further configured to

monitor the number of times of ceasing the supply of the second current is ceased; and

report an error in response to determining that the number of times exceeds a threshold number.
The system (100) of claim 12, wherein the controller is further configured to resume supplying the second current in response to determining that the difference falls below the threshold.
A method of wireless power transfer (WPT) comprising:

supplying a second current to at least one of a first coil (122) and a second coil (122, 112) to generate a magnetic field (200) , the first coil (122) arranged in a first shielding housing (124) , the second coil (112) arranged in a second shielding housing (114) and configured to generate a first current for charging a target device (150) ,

wherein the first and second shielding housings (114, 124) are adapted to be magnetized by the magnetic field (200) to generate an electromagnetic force (F) to cause the first and second coils (122, 112) to be attracted by and aligned with each other.
The method of claim 15, further comprising:

determining a difference a first a charging power associated with the second current and a second power associated with the first current; and

in response to determining that the difference exceeds a threshold, ceasing supplying the second current.
The method of claim 15, further comprising:

resuming supplying the second current in response to determining that the difference falls below the threshold.
A computer program product being tangibly stored on a computer readable storage medium and comprising instructions which, when executed on at least one processor, cause the at least one processor to perform the method according to any of claims 15-17.
A computer-readable medium storing machine-executable instructions, the machine-executable instructions, when executed, enabling the machine to execute the method according to any of claims 15-17.