Flip coil for wireless power transfer

Abstract

Structures, apparatuses, and methods for wireless power transfer systems are described. The structure may include a plurality of strands arranged in one coil layer. For each fixed interval along the length of the structure, the plurality of strands are folded at a lateral angle and vertically inverted in response to folding at the lateral angle. The plurality of strands is folded such that the plurality of strands surrounds the center of the structure in parallel paths.

Description

Background Art

[0001] The present disclosure generally relates to devices and apparatuses that include flip coil configurations.

[0002] A wireless power system may include a transmitter with a transmitting coil and a receiver with a receiving coil. The transmitting coil and the receiving coil may be placed close together to form a transformer that can facilitate the inductive transfer of alternating current (AC) power. The transfer of AC power from the transmitter to the receiver can facilitate charging the battery of the device that includes the receiver. Summary of the Invention

[0003] In one embodiment, a structure is generally described. The structure may include a plurality of strands arranged into a coil layer. At regular intervals along the length of the structure, the strands fold at a transverse angle and invert vertically in response to folding at the transverse angle. The strands are folded such that they circumscribe the center of the structure in parallel paths.

[0004] In one embodiment, a device is generally described. The device may include a power rectifier configured to rectify alternating current (AC) power into direct current (DC) power. The device may further include a controller connected to the power rectifier. The controller may be configured to control the power rectifier. The device may further include a structure configured to receive the AC power. The structure may include a plurality of strands arranged into a coil layer. For each fixed interval along the length of the structure, the plurality of strands are folded at a transverse angle and vertically reversed in response to folding at the transverse angle. The plurality of strands are folded so that the plurality of strands surround the center of the structure in parallel paths.

[0005] In one embodiment, a method for constructing a coil of a device is generally described. The method may include arranging a plurality of strands in parallel paths. The method may further include, at each fixed point along the parallel paths, folding the plurality of strands at a transverse angle to vertically invert the plurality of strands. The folding causes the plurality of strands to form a loop around a central point.

[0006] Further features, structure, and operation of various embodiments are described in detail below with reference to the accompanying drawings. In the drawings, like reference numerals indicate identical or functionally similar elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a block diagram of an example system for wireless power transfer according to an embodiment.

[0008] Figure 2A is a schematic diagram illustrating components of a receiver that can implement a flipping coil for wireless power transfer in one embodiment.

[0009] Figure 2B is another schematic diagram illustrating components of a receiver that can implement a flip coil for wireless power transfer in one embodiment.

[0010] Figure 2C is another schematic diagram illustrating components of a receiver that can implement a flip coil for wireless power transfer in one embodiment.

[0011] Figure 3 is a schematic diagram illustrating a perspective view of an example receiver coil that may implement a flip coil for wireless power transfer in one embodiment.

[0012] Figure 4 is a flow chart illustrating a process of constructing a flip coil for wireless power transfer in one embodiment. DETAILED DESCRIPTION

[0013] In order to facilitate understanding of the different embodiments of the present application, in the following description, many specific details are set forth, such as specific structures, components, materials, dimensions, processing steps and technologies. However, it will be understood by those skilled in the art that the various embodiments of the present application can be implemented without these specific details. In some cases, in order to avoid obscuring the present application, well-known structures or processing steps are not described in detail.

[0014] Figure 1 is a block diagram of an example system 100 for wireless power transmission according to an embodiment. System 100 may include a transmitter 110 and a receiver 120 configured to wirelessly transmit power and data between the transmitter 110 and the receiver 120 via inductive coupling. Although described herein as a transmitter 110 and a receiver 120, each of the transmitter 110 and the receiver 120 may be configured to both transmit and receive power or data between the transmitter 110 and the receiver 120 via inductive coupling.

[0015] The transmitter 110 is configured to receive power from one or more power sources and wirelessly transmit AC power 130 to the receiver 120. For example, the transmitter 110 can be configured to connect to a power source 116, such as an adapter or a DC power source. The transmitter 110 can include a coil TX and can drive the coil TX to generate a magnetic field. The transmitter 110 can be configured to drive the coil TX within a frequency range and configuration range defined by a wireless power standard, such as the Wireless Power Alliance (Qi) standard, the Power Matters Alliance (PMA) standard, the Alliance for Wireless Power (Afor WP or Rezence) standard, or any other wireless power standard.

[0016] The receiver 120 can be configured to receive the AC power 130 transmitted by the transmitter 110 and supply the power to one or more loads 126 or other components of a target device. The load 126 can include, for example, a battery charger configured to charge a battery of a target device, such as a computing device, a mobile device, a mobile phone, a smart device, a tablet, a wearable device, or any other electronic device configured to wirelessly receive power. In one embodiment, the target device can include the receiver 120. In other embodiments, the receiver 120 can be provided separately from the target device, with the receiver 120 being connected to the target device via wires or other components that provide power to the target device.

[0017] The receiver 120 may include a controller 122 and a power rectifier 124. The controller 122 may include, for example, a processor, a central processing unit (CPU), a field programmable gate array (FPGA), or any other circuit that can be configured to control and operate the power rectifier 124. The power rectifier 124 includes a coil RX and is configured to rectify power received via the coil RX into the type of power required by the load 126. The power rectifier 124 is configured to rectify the AC power received from the coil RX into DC power 132, which is then supplied to the load 126.

[0018] For example, when the receiver 120 is placed near the transmitter 110, the magnetic field generated by the coil TX induces a current in the coil RX of the power rectifier 124. The induced current causes AC power 130 to be inductively transferred from the transmitter 110 to the power rectifier 124. The power rectifier 124 receives the AC power 130 and converts the AC power 130 into DC power 132. The DC power 132 is then provided by the power rectifier 124 to the load 126.

[0019] Transmitter 110 and receiver 120 are also configured to exchange information or data, such as messages, via inductive coupling between transmitter 110's power driver and power rectifier 124. For example, before transmitter 110 begins transmitting power to receiver 120, a power agreement may be established between receiver 120 and transmitter 110. In another example, in response to receiver 120 being brought into proximity with transmitter 110, e.g., close enough to form a transformer with coils TX and RX to allow power transfer, receiver 120 may be configured to initiate communication by sending a signal to transmitter 110 requesting power transfer. At this point, transmitter 110 may respond to the request from receiver 120 by establishing a power agreement or, if a power agreement already exists, by beginning to transmit power to receiver 120. Transmitter 110 and receiver 120 may transmit and receive communication packets, data, or other information via inductive coupling between coils TX and RX. In some embodiments, communication between the transmitter 110 and the receiver 120 may occur prior to the power transfer phase using various protocols such as near field communication (NFC), Bluetooth, and the like.

[0020] In one aspect, the receiver coil of a wireless power receiver can be made using multiple strands of wire (e.g., Litz wire or a wire comprising multiple strands). Using multiple strands of wire can reduce the skin depth effect, which refers to the tendency of alternating current (AC) to shift from the center of the wire to the surface of the wire. Depending on the shape of the receiver coil, the multiple strands can have different lengths. For example, if the receiver coil includes two strands of wire, such as an inner strand and an outer strand, arranged in parallel paths around the center to form a loop (e.g., a circular loop, a rectangular loop, or other loop shape), the inner strand (e.g., the strand closer to the center) will be shorter than the outer strand (e.g., the strand farther from the center). This difference in length can cause the multiple strands to experience different magnetic flux generated by the AC current generated by the AC power received by the receiver coil. For example, because the outer strand occupies more area of ​​the receiver coil (e.g., has a longer length), it can experience more magnetic flux than the inner strand. The difference in magnetic flux experienced by the strands of different sizes (e.g., different lengths) can induce a loop current between the strands. This induced loop current can be converted into heat, thereby increasing the temperature of the receiver.

[0021] Figure 1 A receiver coil configuration for reducing loop current is shown. The coil RX of the receiver 120 can include multiple strands (e.g., coils or wires) arranged in a transverse coil layer 140 ("layer 140") in the xy plane. In one embodiment, the coil RX can include a multi-strand coil of multiple strands or wires, such as flat rectangular wire or round wire. The multiple strands can be composed of a conductive material, such as copper.

[0022] The multiple strands may be parallel to each other and may span the width of the coil RX. The multiple strands may extend in parallel and horizontally wrap around a center point (e.g., in the xy plane), so that the coil RX may have a toroidal shape. When the multiple strands extend along parallel paths, the multiple strands may be folded at predetermined fixed intervals along the length of the coil RX to form the toroidal shape of the coil RX. The folding may be performed at a transverse angle (e.g., an angle defined in the xy plane), and the value of the transverse angle may define the toroidal shape of the coil RX. Figure 1 The example in shows the coil RX as a square ring shape, but other shapes are possible (described below).

[0023] For example, a portion 144 of layer 140 is Figure 1 . In section 144, multiple strands can be folded to form the corners of a square ring-shaped coil. This folding can cause the strands to be vertically inverted (e.g., flipped) so that, after folding, the upper surfaces of the strands before folding become the lower surfaces of the strands after folding, and the lower surfaces of the strands before folding become the upper surfaces of the strands after folding. Furthermore, in response to the folding, the innermost strand (e.g., closest to the center of coil RX) of the strands before folding can become the outermost strand of the strands after folding. In response to the folding, the outermost strand (e.g., farthest from the center of coil RX) of the strands before folding can become the innermost strand of the strands after folding. At the next fixed point, the strands can be folded again to flip or vertically invert the coils again. Multiple flipping can make the strands forming coil RX have the same length, thereby reducing loop current. While a multi-strand coil such as coil RX can reduce skin depth effects, having multiple strands of wire of different lengths can increase loop current. Thus, coil RX (or other receiver coils described herein) having multiple strands of wire of equal length can reduce skin depth effects and loop currents.

[0024] Figure 2A 、 2B 2C are schematic diagrams illustrating components of a receiver that may implement a flip coil for wireless power transfer in one embodiment. Figure 2A Shown ( Figure 1 ) layer 140 of coil RX. Figure 2A In the embodiment shown, a plurality of strands, including three strands, may form the coil RX. The plurality of strands may extend along parallel paths about a central point or center 202. Figure 2A The layer 140 shown in FIG has a square ring shape, with the strands folded at an angle α relative to the longitudinal direction of the strands. The angle α can be a transverse angle, or an angle in the xy plane where the layer 140 lies (see FIG. Figure 1 ).

[0025] In order to form Figure 2A As shown in the coil RX, connector 204 can be a starting point where multiple strands can be connected. The multiple strands can wrap outward or away from the center 202 toward another connector 206, where the coil loop ends. At a first fixed point 210, the multiple strands can be folded toward the center 202 at an angle α so that the multiple strands can be flipped or vertically inverted. In one embodiment, to form a Figure 2A In the square loop coil shown, the strands may be folded every 90 degrees around the center 20. In another embodiment, the strands may be folded at fixed lengths in the innermost loop (e.g., the loop of the coil closest to the center 202), and then the strands may be folded at the corners (e.g., every 90 degrees) for loops beyond the innermost loop.

[0026] exist Figure 2B In the example shown, multiple strands are shown labeled A, B, and C. At connector 204, which may be the starting point for forming a loop, strand A is the outermost strand (e.g., the strand furthest from the center of strands A, B, and C). Figure 2A 202 in the center), strand C is the innermost strand (e.g., among strands A, B, and C, closest to Figure 2A After the fixing point 210 is folded at an angle α, the portion 222 of the strands A, B, C can extend in a direction perpendicular to the original portion 220 of the strands A, B, C. In addition, after the fixing point 210 is folded at an angle α (see Figure 2A ), the strands A, B, and C can be vertically reversed or flipped so that the upper surface of the portion 220 of the strands A, B, and C can become the lower surface of the portion 222 of the strands A, B, and C. In addition, after being folded at the angle α at the fixing point 210, the outermost strand A in the portion 220 can become the innermost strand in the portion 222, and the innermost strand C in the portion 220 can become the outermost strand in the portion 222. It should be noted that due to the Figure 2B In the example shown, the multiple strands are three, so the middle strand (i.e., strand B) remains the middle strand after folding and flipping. Thus, for an odd number of strands, the middle strand remains the middle strand, while for an even number of strands, the middle two strands swap after each flip. Multiple flips ensure that the strands have the same length, thus reducing loop currents.

[0027] exist Figure 2C In the example shown, the thickness of the plurality of strands may be represented as T. When the plurality of strands are folded at an angle α, the plurality of strands may be compressed downward, as shown at portion 230, such that portion 220 and portion 222 may remain on the same plane. Additionally, due to the folding and flipping, the thickness at the folded portion 232 (e.g., the triangular portion) may have the plurality of strands overlapped with itself, such that the thickness of portion 232 is 2T. In one embodiment, connectors 204, 206 (see FIG. Figure 2A and Figure 2B ) may have a thickness greater than T and less than 2 T. Increasing the thickness to 2 T may have minimal impact on the overall thickness of the receiver coil.

[0028] Figure 3 is a schematic diagram illustrating a perspective view of an example receiver coil that may implement a flip coil for wireless power transfer in one embodiment. Figure 3 The receiver coil 300 shown in FIG. Figure 1 The receiver coil 300 may include a layer of coils, such as layer 140 described herein. The receiver coil 300 may be a multi-strand coil including a plurality of strands or wires, such as flat rectangular wire or round wire. The plurality of strands forming the receiver coil 300 may be composed of a conductive material, such as copper. Figure 3 In the example shown, the receiver coils 300 may form a hexagonal ring around a center point or center 302 .

[0029] exist Figure 3 In the embodiment shown, the receiver coil 300 can be formed using three strands. The strands can extend along parallel paths about a center point 302. The strands are folded at an angle β relative to the longitudinal direction of the strands. The angle β can be a transverse angle or an angle in the xy plane where the receiver 300 is located (see FIG. Figure 1 To form the receiver coil 300, a connector 304 can be a starting point, and the multiple strands can be connected at the connector 304. The multiple strands can wrap outward, or away from the center 302, toward another connector 306, where the loop of the receiver coil 300 ends. At a first fixing point 310, the multiple strands can be folded at an angle β toward the center 302, allowing the multiple strands to be flipped or inverted vertically. In one embodiment, to form a hexagonal receiver coil 300, the multiple strands can be folded every 60 degrees around the center 302.

[0030] After folding at angle β at fixed point 310, the strands can be vertically inverted or flipped so that the upper surfaces of the strands before folding become the lower surfaces of the strands after folding, and vice versa. Furthermore, after folding at angle β at fixed point 310, the outermost strand before folding can become the innermost strand after folding, and the innermost strand before folding can become the outermost strand after folding. Repeated flipping can allow the strands to have the same length, thereby reducing skin depth effects.

[0031] Figure 44 is a flow chart illustrating a process for constructing a flip coil for wireless power transfer in one embodiment. The process may include one or more operations, actions, or functions illustrated by one or more of blocks 402 and / or 404. Although illustrated as discrete blocks, various blocks may be divided into additional blocks, combined into fewer blocks, eliminated, performed in a different order, or performed in parallel, depending on the desired implementation.

[0032] Process 400 may be performed to construct a coil for a device, such as a receiver coil for a wireless power receiver. Process 400 may begin at block 402. At block 402, a plurality of strands may be arranged in parallel paths. In one embodiment, the plurality of strands may form a multi-stranded wire. In one embodiment, the plurality of strands may be flat rectangular wires. In one embodiment, the plurality of strands may have the same length.

[0033] From block 402, process 400 may proceed to block 404. At block 404, at each fixed point along the parallel path, the plurality of strands may be folded at a transverse angle to vertically flip the plurality of strands. The folding may cause the plurality of strands to form a loop around a central point. In one embodiment, the shape of the structure may be based on the transverse angle.

[0034] In one embodiment, the folding of the plurality of strands may cause the outermost strand of the plurality of strands to become the new innermost strand of the plurality of strands. The folding of the plurality of strands may also cause the innermost strand of the plurality of strands to become the new outermost strand of the plurality of strands.

[0035] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of the systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram may represent a module, an instruction segment, or an instruction portion, which includes one or more executable instructions for implementing a specified logical function. In some optional embodiments, the functions marked in the box may not occur in the order marked in the figure. For example, two blocks shown in succession may actually be executed substantially simultaneously, or the boxes may sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, may be implemented by a dedicated hardware-based system that performs a specified function or action or performs a combination of dedicated hardware and computer instructions.

[0036] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that when the term "comprising" is used in this specification to specify the presence of the features, wholes, steps, operations, elements and / or parts, it does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, parts and / or combinations thereof.

[0037] In the claims below, the corresponding structures, materials, actions and equivalents of all means or step plus function elements, if any, are intended to include any structure, material or action for performing a function in conjunction with other claimed elements for specific protection. The above description of the application is for the purpose of illustration and description, but is not intended to be exhaustive or limited to the disclosed form. Without departing from the scope and spirit of the invention, many modifications and variations will be apparent to those of ordinary skill in the art. This embodiment is selected and described in order to best explain the principles of the invention and practical applications, and to enable other persons of ordinary skill in the art to understand the present invention for various embodiments with various modifications suitable for the specific use intended.

Claims

1. A structure comprising: A plurality of strands arranged into a coil layer, wherein: For each fixed interval along the length of the structure, the plurality of strands fold at a transverse angle and invert vertically in response to folding at the transverse angle; and The plurality of strands are folded such that the plurality of strands circumscribe the center of the structure in parallel paths.

2. The structure according to claim 1, wherein The plurality of strands form a multi-stranded wire.

3. The structure according to claim 1, wherein The plurality of strands have the same length.

4. The structure according to claim 1, wherein The shape of the structure is based on the lateral angle.

5. The structure according to claim 1, wherein The plurality of strands are part of a wireless power receiver.

6. The structure according to claim 1, wherein In response to folding at the landscape angle: The outermost strand of the plurality of strands becomes the new innermost strand of the plurality of strands; and The innermost strand of the plurality of strands becomes the new outermost strand of the plurality of strands.

7. The structure according to claim 1, wherein The plurality of strands are flat rectangular wires.

8. A device comprising: a power rectifier configured to rectify alternating current (AC) power into direct current (DC) power; a controller connected to the power rectifier, the controller being configured to control the power rectifier; a structure configured to receive the AC power, the structure comprising a plurality of strands arranged into a coil layer, wherein: For each fixed interval along the length of the structure, the plurality of strands fold at a transverse angle and invert vertically in response to folding at the transverse angle; as well as The plurality of strands are folded such that the plurality of strands circumscribe the center of the structure in parallel paths.

9. The apparatus according to claim 8, wherein The plurality of strands form a multi-stranded wire.

10. The apparatus according to claim 8, wherein The controller, the power rectifier, and the structure are part of a wireless power receiver.

11. The apparatus according to claim 8, wherein The plurality of strands have the same length.

12. The apparatus according to claim 8, wherein The shape of the structure is based on the lateral angle.

13. The apparatus according to claim 8, wherein In response to folding at the landscape angle: The outermost strand of the plurality of strands becomes the new innermost strand of the plurality of strands; and The innermost strand of the plurality of strands becomes the new outermost strand of the plurality of strands.

14. The apparatus according to claim 8, wherein The plurality of strands are flat rectangular wires.

15. A method for constructing a coil of a device, the method comprising: Arranging multiple strands in parallel paths; as well as At each fixed point along the parallel paths, the plurality of strands are folded at a transverse angle to vertically invert the plurality of strands, wherein the folding causes the plurality of strands to form a loop about a center point.

16. The method according to claim 15, wherein The plurality of strands form a multi-stranded wire.

17. The method according to claim 15, wherein: The plurality of strands have the same length.

18. The method according to claim 15, wherein The shape of the coil is based on the lateral angle.

19. The method according to claim 15, wherein Folding the plurality of strands includes: switching an outermost strand of the plurality of strands to a new innermost strand of the plurality of strands; and An innermost strand of the plurality of strands is switched to a new outermost strand of the plurality of strands.

20. The method according to claim 15, wherein The plurality of strands are flat rectangular wires.

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