Modular stacking method of magnetic coupling structure for wireless power transmission system

Abstract

The present invention proposes a modular stacking method for a magnetic coupling structure of a wireless power transmission system. The method stacks a plurality of magnetic coupling modules in a radial shape distribution or a linear arrangement distribution to improve the coupling coefficient between a receiving coil and a transmitting coil in the magnetic coupling module; the receiving coil and the transmitting coil are parallel to each other and have the same orientation, and both include a flat solenoid coil wound on the surface of a magnetic core; when a plurality of magnetic coupling modules are stacked in a radial shape in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system, the magnetic field directions of the plurality of magnetic coupling modules all point to the radiation origin; when a plurality of magnetic coupling modules are stacked in a linear arrangement in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system, the plurality of magnetic coupling modules are adjacent end to end and have the same magnetic field direction; the present invention can improve the coupling coefficient between the receiving coil and the transmitting coil by stacking multiple modules.

Description

Technical Field

[0001] The invention relates to the technical field of wireless power transmission, in particular to a modular stacking method of a magnetic coupling structure of a wireless power transmission system. Background Art

[0002] Wireless Power Transfer (WPT) technology refers to an energy transmission technology that uses electromagnetic waves or sound waves as energy transmission media to achieve energy transfer from power source to load without electrical contact. Compared with traditional energy transmission technology, this technology has the advantages of safety, reliability, and flexibility, and has attracted widespread attention from scholars at home and abroad.

[0003] In recent years, wireless power transmission technology for electric vehicles has become a research hotspot, and wireless charging technology with power levels ranging from several kilowatts to tens of kilowatts has been widely studied and applied. However, the current mainstream wireless charging power levels cannot meet the user's charging speed requirements, and high-power wireless charging technology needs to be studied. Modularization is a solution to achieve high-power wireless charging. By adjusting the number of modules, the requirements of different power levels can be met. At the same time, modular wireless charging technology can save a lot of design and testing work, which is conducive to production. The magnetic coupling structure of each module and the stacking method of each module are closely related to the performance of the modular wireless power transmission system, so they need to be studied.

[0004] The coupling coefficient of the traditional modular wireless charging system is small, and the coupling coefficient does not increase with the increase in the number of modules, which needs to be solved. Summary of the invention

[0005] The present invention proposes a modular stacking method for a magnetic coupling structure of a wireless power transmission system, which can improve the coupling coefficient between a receiving coil and a transmitting coil by stacking multiple modules.

[0006] The present invention adopts the following technical solutions.

[0007] A modular stacking method for a magnetic coupling structure of a wireless power transmission system, wherein a plurality of magnetic coupling modules are stacked in a radial distribution or a linear arrangement to improve the coupling coefficient between a receiving coil and a transmitting coil in the magnetic coupling module; the receiving coil and the transmitting coil are parallel to each other and face the same direction, and both include a flat solenoid coil wound on the surface of a magnetic core; when a plurality of magnetic coupling modules are stacked in a radial shape in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system, the magnetic field directions of the plurality of magnetic coupling modules all point to the radiation origin; when a plurality of magnetic coupling modules are stacked in a linear arrangement in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system, the plurality of magnetic coupling modules are adjacent end to end and have the same magnetic field direction.

[0008] The magnetic core is a ferrite in a rectangular shape.

[0009] The receiving coil and the transmitting coil in the magnetic coupling module have the same length, width, height, air gap length, stacking gap, and Litz wire specifications of the magnetic core; when the number of magnetic coupling modules increases, the coupling coefficient between the receiving coil and the transmitting coil also increases after multiple magnetic coupling modules are stacked.

[0010] The magnetic coupling module is a wireless power transmission WPT module. When the magnetic coupling modules are stacked, the air gap length is the distance between the transmitting end and the receiving end of the wireless power transmission system, and the stacking gap is the gap between each flat solenoid magnetic coupling module.

[0011] In the equivalent circuit of the WPT module, L1 and R1 are the self-inductance and equivalent resistance of the transmitting coil, L2 and R2 are the self-inductance and equivalent resistance of the receiving coil, I1 and I2 are the currents of the transmitting coil and the receiving coil, respectively. The power from the transmitting coil to the receiving coil is expressed as P = ωMI1I2sinθ 12 Formula 1;

[0012] Where ω is the operating angular frequency of the system, θ 12 is the vector angle between I1 and I2;

[0013] When ω=90°, the maximum transmission power is

[0014] P max =ωMI1I2 Formula 2;

[0015] Formula 2 is transformed into

[0016]

[0017] L 10 and L 20 is the self-inductance of a single-turn coil, N1 and N2 are the number of turns of the transmitting coil and the receiving coil respectively, and k is the coupling coefficient of the system. The self-inductance relationship between a single-turn coil and a multi-turn coil is expressed as

[0018] As shown in Formula 3, the maximum transmission power of the wireless power transmission system is proportional to the coupling coefficient k of the system; when the transmission power of the system is maximum, the transmission efficiency of the system is

[0019]

[0020] when The maximum transmission efficiency is

[0021]

[0022] Among them, Q1 and Q2 are quality factors, which are defined by formula 8:

[0023]

[0024] The solution proposed in the present invention adopts flat solenoids, which can achieve better magnetic circuit multiplexing through parallel arrangement or radial arrangement. Compared with traditional solutions, the coupling coefficient of the system is significantly improved, and the coupling coefficient can increase with the increase in the number of modules. Therefore, the performance of the system under high power output can be improved by significantly improving the coupling coefficient of the traditional wireless power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0026] Attached Figure 1 It is a structural schematic diagram of the magnetic coupling module in the present invention;

[0027] Attached Figure 2 It is a top view schematic diagram of a plurality of magnetic coupling modules arranged in a straight line and stacked in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system in the present invention;

[0028] Attached Figure 3 It is a top view schematic diagram of a plurality of magnetic coupling modules stacked in a radial shape distribution in the present invention (the radial shape includes a triangle, a quadrilateral, a pentagon, and a hexagon);

[0029] Attached Figure 4 It is a curve diagram showing that the coupling coefficient increases with the number of magnetic coupling modules (Scheme 1 in the figure is arranged in a straight line, and Scheme 2 is arranged in a radial shape);

[0030] Attached Figure 5 It is a schematic diagram of a magnetic coupling module using a planar square coil under conventional technology;

[0031] Attached Figure 6 It is a schematic diagram of the stacking of magnetic coupling modules using planar square coils under conventional technology;

[0032] Attached Figure 7 It is another stacking schematic diagram of magnetic coupling modules using planar square coils under conventional technology;

[0033] Attached Figure 8 It is a curve diagram showing the change of coupling coefficient with the number of modules under the traditional technology;

[0034] In the figure: 1-receiving coil; 2-transmitting coil; 3-magnetic core; 4-magnetic coupling module. DETAILED DESCRIPTION

[0035] As shown in the figure, a modular stacking method of a magnetic coupling structure of a wireless power transmission system, the method stacks multiple magnetic coupling modules in a radial shape distribution or a linear arrangement distribution to improve the coupling coefficient between the receiving coil and the transmitting coil in the magnetic coupling module; the receiving coil and the transmitting coil are parallel to each other and have the same orientation, and both include a flat solenoid coil wound on the surface of a magnetic core; when multiple magnetic coupling modules are stacked in a radial shape in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system, the magnetic field directions of the multiple magnetic coupling modules all point to the radiation origin; when multiple magnetic coupling modules are arranged in a linear arrangement and distributed in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system, the multiple magnetic coupling modules are adjacent end to end and have the same magnetic field direction.

[0036] The magnetic core is a ferrite in a rectangular shape.

[0037] The receiving coil and the transmitting coil in the magnetic coupling module have the same length, width, height, air gap length, stacking gap, and Litz wire specifications of the magnetic core; when the number of magnetic coupling modules increases, the coupling coefficient between the receiving coil and the transmitting coil also increases after multiple magnetic coupling modules are stacked.

[0038] The magnetic coupling module is a wireless power transmission WPT module. When the magnetic coupling modules are stacked, the air gap length is the distance between the transmitting end and the receiving end of the wireless power transmission system, and the stacking gap is the gap between each flat solenoid magnetic coupling module.

[0039] In the equivalent circuit of the WPT module, L1 and R1 are the self-inductance and equivalent resistance of the transmitting coil, L2 and R2 are the self-inductance and equivalent resistance of the receiving coil, I1 and I2 are the currents of the transmitting coil and the receiving coil, respectively. The power from the transmitting coil to the receiving coil is expressed as P = ωMI1I2sinθ 12 Formula 1;

[0040] Where ω is the operating angular frequency of the system, θ 12 is the vector angle between I1 and I2;

[0041] When ω=90°, the maximum transmission power is

[0042] P max =ωMI1I2 Formula 2;

[0043] Formula 2 is transformed into

[0044]

[0045] L 10 and L 20 is the self-inductance of a single-turn coil, N1 and N2 are the number of turns of the transmitting coil and the receiving coil respectively, and k is the coupling coefficient of the system. The self-inductance relationship between a single-turn coil and a multi-turn coil is expressed as

[0046] As shown in Formula 3, the maximum transmission power of the wireless power transmission system is proportional to the coupling coefficient k of the system; when the transmission power of the system is maximum, the transmission efficiency of the system is

[0047]

[0048] when

[0049] The maximum transmission efficiency is

[0050]

[0051] Among them, Q1 and Q2 are quality factors, which are defined by formula 8:

[0052]

[0053] In this example, when multiple magnetic coupling modules are stacked in a radiation shape in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system, the magnetic poles of the multiple magnetic coupling modules at one end close to the radiation origin are the same and adjacent.

[0054] In this example, electromagnetic modeling and simulation are performed for the linear and radial stacking designs of the modules. The coupling coefficients obtained by simulation are shown in the figure below: Figure 4 As shown in the figure, compared with the traditional solution, the coupling coefficient of the system using the solution proposed by the present invention is larger, and as the number of modules increases, the coupling coefficient of the system continues to increase. In addition, when the number of modules is the same, the coupling coefficient of the system using the linear stacking solution is larger because the linear stacking solution achieves better magnetic circuit reuse.

Claims

1. A modular stacking method for a magnetic coupling structure of a wireless power transmission system, characterized in that: The method stacks a plurality of magnetic coupling modules in a radial distribution or a linear arrangement to improve the coupling coefficient between the receiving coil and the transmitting coil in the magnetic coupling module; the receiving coil and the transmitting coil are parallel to each other and face the same direction, and both include a flat solenoid coil wound on the surface of a magnetic core; when the plurality of magnetic coupling modules are stacked in a radial shape in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system, the magnetic field directions of the plurality of magnetic coupling modules all point to the radiation origin; when the plurality of magnetic coupling modules are stacked in a linear arrangement in the same horizontal plane to form a magnetic coupling structure of a wireless power transmission system, the plurality of magnetic coupling modules are adjacent end to end and have the same magnetic field direction; The magnetic coupling module is a wireless power transmission WPT module. When the magnetic coupling modules are stacked, the air gap length is the distance between the transmitting end and the receiving end of the wireless power transmission system, and the stacking gap is the gap between each flat solenoid magnetic coupling module; In the equivalent circuit of the WPT module, L1 and R1 are the self-inductance and equivalent resistance of the transmitting coil, L2 and R2 are the self-inductance and equivalent resistance of the receiving coil, I1 and I2 are the currents of the transmitting coil and the receiving coil, respectively; the power from the transmitting coil to the receiving coil is expressed as P=ωMI1I2sinθ 12 Formula 1; Where ω is the operating angular frequency of the system, θ 12 is the vector angle between I1 and I2; When ω=90°, the maximum transmission power is Pmax=ωMI1I2 Formula 2; Formula 2 is transformed into L 10 and L 20 is the self-inductance of a single-turn coil, N1 and N2 are the number of turns of the transmitting coil and the receiving coil respectively, and k is the coupling coefficient of the system; the self-inductance relationship between a single-turn coil and a multi-turn coil is expressed as As shown in Formula 3, the maximum transmission power of the wireless power transmission system is proportional to the coupling coefficient k of the system; when the transmission power of the system is maximum, the transmission efficiency of the system is when The maximum transmission efficiency is Among them, Q1 and Q2 are quality factors, which are defined by formula 8:

2. The modular stacking method of the magnetic coupling structure of the wireless power transmission system according to claim 1, characterized in that: The magnetic core is a ferrite in a rectangular shape.

3. The modular stacking method of the magnetic coupling structure of the wireless power transmission system according to claim 1, characterized in that: The receiving coil and the transmitting coil in the magnetic coupling module have the same length, width, height, air gap length, stacking gap, and Litz wire specifications of the magnetic core; when the number of magnetic coupling modules increases, the coupling coefficient between the receiving coil and the transmitting coil also increases after multiple magnetic coupling modules are stacked.

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