A wireless power transfer magnetic concentrator pad

Abstract

The application provides a wireless power transmission magnetic concentrator pad, the transmitting coil and the receiving coil are symmetrically matched, the distance between the transmitting coil and the receiving coil is 20 mm, and there is a 20 mm misalignment in the vertical and horizontal directions; the electromagnetic field of the transmitting coil and the receiving coil is concentrated on the specified +Z vector, and there is no transverse leakage magnetic flux on the ±Y vector; the transmitting coil or the receiving coil comprises two ferrite blocks and three tubular ferrites, and the ferrite blocks and the tubular ferrites are alternately connected; the application does not need additional mechanical shielding to manage the leakage magnetic field. The application realizes effective power transmission and reception between WPT boards, effectively concentrates power on the target, improves the misalignment tolerance, improves power reception and reduces power loss; the inductance L value of the designed system is effectively maintained, so that the magnetic coupling MC and the power transmission efficiency PTE are improved; and the overall efficiency of the system is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless charging, and in particular relates to a wireless power transmission magnetic concentrator pad. Background Art

[0002] Wireless power transfer (WPT) technology has garnered significant attention in recent years, driven primarily by the increasing demand for efficient and convenient power solutions across a wide range of applications. Currently, there are two primary types of magnetically coupled designs: circular and rectangular. Both utilize transmitter and receiver board windings fabricated from Litz wire, typically arranged in a flat "pancake" winding configuration. This design optimizes performance and reduces leakage flux (Lk) by effectively confining the magnetic field between the windings using aluminum plates on the outer surfaces of the windings, but this comes at the cost of additional cost and system complexity. Meanwhile, conventional WPT boards typically utilize a "monopole" geometry, characterized by a single electromagnetic field (EMF) pole. This design is particularly susceptible to leakage magnetic fields due to several factors. Aluminum and copper are commonly used as shielding materials due to their high conductivity and ability to generate eddy currents that counteract the incident magnetic flux, but they also induce losses in the shield. Summary of the Invention

[0003] This application aims to improve the overall efficiency of wireless power systems, minimize interference from leakage magnetic fields, and enhance the accuracy of energy transfer between WPT panels. It proposes a wireless power transfer magnetic concentrator pad that utilizes bipolar active magnetic focusing technology to effectively eliminate back-side leakage of electromagnetic fields. By connecting the guide coil to the transmitting coil, the magnetic fields cancel each other out and conduct the field from the Tx to the receiving coil Rx. This enables efficient power transmission and reception between the WPT panels, and because power is effectively concentrated at the target, the overall efficiency of the drive system is improved.

[0004] Specifically, the wireless power transmission magnetic concentrator pad described in the present invention includes a transmitting coil and a receiving coil. Preferably, the transmitting coil and the receiving coil are used symmetrically; the spacing between the transmitting coil and the receiving coil is 20 mm, and there is a 20 mm offset in the vertical and horizontal directions; the electromagnetic field of the transmitting coil and the receiving coil is concentrated on a specified +Z vector, and there is no transverse leakage flux on the ±Y vectors; the transmitting coil or the receiving coil includes two ferrite blocks and three tubular ferrites, and the ferrite blocks and the tubular ferrites are alternately connected;

[0005] In Cartesian three-dimensional space, the +Z vector is defined to represent the upward direction; the -Z vector represents the downward direction; the right direction corresponds to the +X vector, and the left direction corresponds to the -X vector; the -Y vector represents the forward direction, and the +Y vector represents the backward direction.

[0006] Preferably, the tubular ferrite includes a first tubular ferrite, a second tubular ferrite and a third tubular ferrite; the second tubular ferrite is twice as long as the first tubular ferrite and the third tubular ferrite.

[0007] The ferrite blocks include a first ferrite block and a second ferrite block; the X plane and the Y plane of the first ferrite block and the second ferrite block are designed to be equal to the outer diameter of the tubular ferrite.

[0008] The second tubular ferrite is connected between the first ferrite block and the second ferrite block. The other end of the first ferrite block is connected to the first tubular ferrite. The other end of the second ferrite block is connected to the third tubular ferrite.

[0009] Preferably, the height of the first ferrite block and the second ferrite block is at least greater than the outer diameter of the tubular ferrite, and greater than one fifth of the outer diameter of the tubular ferrite.

[0010] Preferably, the transmitting coil or receiving coil described in the present application further includes: a first coil winding, a second coil winding, a third coil winding, a fourth coil winding and a fifth coil winding;

[0011] The first coil winding, the third coil winding and the fifth coil winding are respectively arranged inside the first tubular ferrite, the second tubular ferrite and the third tubular ferrite, and all serve as focusing windings for guiding the magnetic field;

[0012] The second coil winding and the fourth coil winding are tightly mounted on the first ferrite block and the second ferrite block +Z vector plane respectively, serving as bipolar power windings.

[0013] Preferably, the first coil winding, the third coil winding and the fifth coil winding are all tubular axial spiral structures.

[0014] The first and fifth coil windings are arranged to align the magnetic field along vector +X; the third coil winding directs the magnetic field in the -X direction.

[0015] Preferably, the second coil winding and the fourth coil winding are both rectangular spiral structures.

[0016] The second coil winding and the fourth coil winding generate an electromagnetic field directed towards +Z.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention eliminates the need for additional mechanical shielding to manage leakage magnetic fields. Effective power transmission and reception is achieved between WPT panels, and the wireless power transmission magnetic concentrator pad provided by this application effectively concentrates power on the target, improving the overall efficiency of the drive system and increasing misalignment tolerance, thereby improving power reception and reducing power loss. The inductance L value of the designed system is effectively maintained, thereby improving magnetic coupling MC and power transmission efficiency PTE. This makes the wireless power transmission magnetic concentrator pad described in this application more cost-effective than currently used traditional systems. Therefore, this design significantly improves the overall efficiency of the system by optimizing magnetic field management. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. 1 is a schematic diagram of the operation of a wireless power transmission magnetic concentrator pad Tx and Rx in this embodiment.

[0020] Figure 2 This is a diagram showing the working effects of Tx and Rx in this embodiment.

[0021] Figure 3 This is a diagram showing the working effects of the Z-axis viewing angle Tx and Rx in this embodiment.

[0022] Figure 4 This is a diagram showing the working effects of the Y-axis viewing angle Tx and Rx in this embodiment.

[0023] Figure 5 Schematic diagram of the wireless power transmission magnetic concentrator pad in this embodiment.

[0024] Figure 6 This is a structural diagram of the wireless power transmission magnetic concentrator pad from the Y direction perspective in this embodiment.

[0025] Figure 7 This is a structural diagram of the wireless power transmission magnetic concentrator pad from an X-direction perspective in this embodiment.

[0026] Figure 8 It is the tubular ferrite in this embodiment.

[0027] Figure 9 It is the ferrite block in this embodiment.

[0028] Figure 10 Graph depicting the electromagnetic field lines in this embodiment.

[0029] Figure 11 This is the magnetic field distribution diagram in this embodiment.

[0030] Figure 12 This is the electrical connection in the current embodiment of this embodiment.

[0031] Among them, 1 is a transmitter Tx; 2 is a receiver Rx; 11 is a first tubular ferrite, 12 is a second tubular ferrite; 13 is a third tubular ferrite; 21 is a first ferrite block; 22 is a second ferrite block; 31 is a first coil winding; 32 is a second coil winding; 33 is a third coil winding; 34 is a fourth coil winding; 35 is a fifth coil winding. DETAILED DESCRIPTION

[0032] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0033] The isometric view of the current embodiment is used for finite element analysis (FEA) simulation. The wireless power transmission magnetic concentrator pad described in the present invention is designed to significantly reduce and possibly eliminate the leakage magnetic field EMF generated by the interconnected wireless power transmission (WPT) boards, improve the power transmission efficiency (PTE) by reducing the core loss (Pfe) and copper loss (Pcu) as well as the leakage flux (Lk), and increase the mutual inductance (MI) through a good coupling coefficient (k), inductance (L), and quality factor (Q). Among them, the coupling coefficient (k) between the transmitter (Tx) and receiver (Rx) boards is a key factor in achieving a cost-effective and efficient WPT system. This application will only focus on wireless power transmission (WPT) systems using inductive power transmission (IPT) technology, specifically the geometry and performance of the transmitter (Tx) and receiver (Rx) board elements.

[0034] Specifically, such as Figure 1-4 As shown, the wireless power transmission magnetic concentrator pad described in this application includes a transmitting coil and a receiving coil, which are used symmetrically; the spacing between the transmitting coil and the receiving coil is 20mm, and there is a 20mm offset in the vertical (Y axis) and horizontal directions (X axis); the electromagnetic field of the transmitting coil and the receiving coil is concentrated on the specified +Z vector, and there is no transverse leakage flux on the ±Y vectors; the transmitting coil or the receiving coil includes two ferrite blocks and three tubular ferrites, and the ferrite blocks and tubular ferrites are connected alternately; this application uses bipolar active magnetic focusing technology to effectively eliminate back leakage of the electromagnetic field. By connecting the guide coil to the transmitting coil, the magnetic fields can cancel each other and conduct the field from Tx to the receiving coil Rx.

[0035] In Cartesian three-dimensional space, vectors are identified by their direction. To clarify their representation within this spatial framework, the following directions are defined: the +Z vector represents the upward direction, and the -Z vector represents the downward direction. The rightward direction corresponds to the +X vector, and the leftward direction corresponds to the -X vector. Furthermore, the -Y vector represents the forward direction, and the +Y vector represents the backward direction.

[0036] Further, such as Figure 8 As shown, the tubular ferrite includes a first tubular ferrite, a second tubular ferrite and a third tubular ferrite; the second tubular ferrite is twice as long as the first tubular ferrite and the third tubular ferrite, thereby enhancing its function in the system and preventing crosstalk of the magnetic field between the first tubular ferrite and the third tubular ferrite.

[0037] It should be noted that the thickness of the tubular ferrite is determined by several factors, including power output and the specific ferrite material used in the end application system, thereby tailoring performance to meet requirements.

[0038] Among them, such as Figure 9 As shown, the ferrite block includes a first ferrite block and a second ferrite block; the X plane and Y plane of the first ferrite block and the second ferrite block are designed to be equal to the outer diameter of the tubular ferrite to ensure a tight fit between the two.

[0039] like Figure 5-7 As shown, a second tubular ferrite is connected between the first and second ferrite blocks to effectively prevent the bipolar transmitter from inducing magnetic crosstalk. The spacing between the two blocks ensures minimal separation. The first ferrite block is connected to the first tubular ferrite at its other end, while the second ferrite block is connected to the third tubular ferrite at its other end.

[0040] Preferably, the height of the first and second ferrite blocks is one-fifth greater than the outer diameter of the tubular ferrite. By adhering to a height threshold of one-fifth of the tubular outer diameter, a safer operating margin can be established, thereby reducing the potential risk of magnetic flux leakage and avoiding adverse effects on system efficiency. This enhances the mechanical stability and performance of the assembly on the respective coils, ensuring that the device maintains its electromagnetic integrity.

[0041] Preferably, Figure 5 As shown, the transmitting coil or receiving coil described in the present application has a total of five coil windings including: a first coil winding, a second coil winding, a third coil winding, a fourth coil winding and a fifth coil winding;

[0042] The first coil winding, the third coil winding and the fifth coil winding are respectively arranged inside the first tubular ferrite, the second tubular ferrite and the third tubular ferrite, and all serve as focusing windings for guiding the magnetic field;

[0043] The second and fourth coil windings are mounted closely to the +Z vector plane of the first and second ferrite blocks, respectively, with their top edges aligned. The second and fourth coil windings function as bipolar power windings for either Tx or Rx operation, ensuring optimal magnetic coupling occurs at the top edge of each ferrite block. This eliminates the need for metal shielding in the -Z direction and makes the system more cost-effective than currently used conventional systems. This design significantly improves overall system efficiency by optimizing magnetic field management.

[0044] Preferably, the first coil winding, the third coil winding and the fifth coil winding are all tubular axial spiral structures.

[0045] The first and fifth coil windings are arranged to align the magnetic field along vector +X; the third coil winding directs the magnetic field in the -X direction.

[0046] Preferably, the second coil winding and the fourth coil winding are both rectangular spiral structures. It should be noted that the rectangular spiral structure has superior coupling performance than the circular coil. Rectangular coils often exhibit higher efficiency in certain configurations because their geometric shape helps improve the coupling between the transmitter and receiver boards. The rectangular shape helps increase the overlap of magnetic field lines, which is particularly beneficial in scenarios where alignment is critical. The increased overlap helps to enhance mutual inductance. In addition, the rectangular magnetic coupling shape can reduce leakage flux compared to the circular magnetic coupling shape in certain configurations, thereby improving power transmission efficiency.

[0047] The second coil winding and the fourth coil winding generate an electromagnetic field directed towards +Z.

[0048] like Figure 10 As shown, the electromagnetic field lines are depicted, with no leakage of surrounding electromagnetic fields. Clearly, the system provided by the present invention effectively guides the transmit electromagnetic field to the receive receiver, with minimal leakage flux. Notably, the system of the present invention does not employ passive back shielding, thereby reducing overall costs and ensuring compliance with the requirements of the International Special Committee on Radio Frequency Interference (CISPR) regulations on electromagnetic compatibility (EMC).

[0049] like Figure 11 As shown in Figure 1, the Tx or Rx mode of operation is demonstrated. As a standalone bipolar embodiment, it can be clearly seen that the electromagnetic field (EMF) is effectively concentrated on the designated +Z vector. There is no transverse leakage flux on the ±Y vectors.

[0050] like Figure 12The electrical connections for the current embodiment are shown. As shown, all coils are powered by the same current, which simplifies implementation and eliminates the need for a control system. Each coil has its own core ferrite geometry; however, they exhibit different physical winding directions and current directions, starting from input 80.

[0051] In this representation, the first coil winding 31 corresponds to 81, the second coil winding 32 corresponds to 82, the third coil winding 33 corresponds to 83, the fourth coil winding 34 corresponds to 84, and the fifth coil winding 35 corresponds to 85; the electromagnetic field is shown in dots, and all coils share a common core. It should be noted that the drive current can be configured as constant current (CC) or alternating current (AC), and its waveform can be either a sine wave or a square wave.

[0052] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A wireless power transmission magnetic concentrator pad, comprising a transmitting coil and a receiving coil, characterized in that: The transmitting coil and receiving coil are used symmetrically; the spacing between the transmitting coil and the receiving coil is 20 mm, and there is a 20 mm offset in the Y and X directions; the electromagnetic field of the transmitting coil and the receiving coil is concentrated on the specified +Z vector, and there is no transverse leakage flux on the ±Y vectors; the transmitting coil or the receiving coil includes two ferrite blocks and three tubular ferrites, and the ferrite blocks and tubular ferrites are alternately connected. In Cartesian three-dimensional space, the +Z vector is defined to represent the upward direction; the -Z vector represents the downward direction; the right direction corresponds to the +X vector, and the left direction corresponds to the -X vector; the -Y vector represents the forward direction, and the +Y vector represents the backward direction; The tubular ferrite includes a first tubular ferrite, a second tubular ferrite and a third tubular ferrite; the second tubular ferrite is twice as long as the first tubular ferrite and the third tubular ferrite; The ferrite block includes a first ferrite block and a second ferrite block; The second tubular ferrite is connected between the first ferrite block and the second ferrite block, and the other end of the first ferrite block is connected to the first tubular ferrite; the other end of the second ferrite block is connected to the third tubular ferrite; The transmitting coil or receiving coil further includes: a first coil winding, a second coil winding, a third coil winding, a fourth coil winding, and a fifth coil winding; The first coil winding, the third coil winding and the fifth coil winding are respectively arranged inside the first tubular ferrite, the second tubular ferrite and the third tubular ferrite, and all serve as focusing windings for guiding the magnetic field; The second coil winding and the fourth coil winding are tightly mounted on the first ferrite block and the second ferrite block +Z vector plane respectively, serving as bipolar power windings.

2. The wireless power transmission magnetic concentrator pad according to claim 1, characterized in that: The X-plane and the Y-plane of the first ferrite block and the second ferrite block are designed to be equal to the outer diameter of the tubular ferrite.

3. The wireless power transmission magnetic concentrator pad according to claim 2, characterized in that: The heights of the first ferrite block and the second ferrite block are at least one-fifth greater than the outer diameter of the tubular ferrite.

4. The wireless power transmission magnetic concentrator pad according to claim 3, characterized in that: The first coil winding, the third coil winding and the fifth coil winding are all tubular axial spiral structures.

5. The wireless power transmission magnetic concentrator pad according to claim 4, characterized in that: The first coil winding and the fifth coil winding are arranged to align the magnetic field along vector +X; The third coil winding directs the magnetic field into the -X direction.

6. The wireless power transmission magnetic concentrator pad according to claim 5, characterized in that: The second coil winding and the fourth coil winding are both rectangular spiral structures.

7. The wireless power transmission magnetic concentrator pad according to claim 6, characterized in that: The second coil winding and the fourth coil winding generate an electromagnetic field directed towards +Z.

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