Novel magnetic coupling mechanism and multi-load induction type wireless charging system

Abstract

The invention discloses a novel magnetic coupling mechanism which comprises a W-shaped wireless charging coil, a staggered magnetic core and an aluminum plate, the W-shaped wireless charging coil is formed by overlapping a first wireless charging coil and a second wireless charging coil, and the staggered magnetic core is formed by transversely and longitudinally crossed strip-shaped magnetic cores; the invention further discloses a multi-load induction type wireless charging system. The W-type wireless charging coil forms a plurality of rectangular charging areas in a plane through the transverse wiring and the longitudinal wiring, magnetic fluxes of the adjacent rectangular charging areas are mutually linked to form series magnetic fluxes, the series magnetic fluxes improve the intensity of a magnetic field, and the anti-offset capability between the W-type wireless charging coil and the receiving coil is also improved. When alternating current is introduced into the W-shaped wireless charging coil, alternating magnetic flux is generated in the rectangular charging area, so that energy is transmitted to a receiving end circuit.

Description

Technical Field

[0001] This invention belongs to the field of wireless charging technology, and particularly relates to a novel magnetic coupling mechanism and a multi-load inductive wireless charging system. Background Technology

[0002] There are three basic forms of wireless power transfer technology: inductive wireless power transfer technology, resonant wireless power transfer technology, and microwave wireless power transfer technology.

[0003] Inductive wireless power transfer technology can be implemented through two principles: one is based on the principle of electromagnetic induction, where the transmitting coil and receiving coil are placed at a very close distance. When an alternating current is passed through the transmitting coil, the alternating current generates an alternating magnetic field, and the alternating magnetic flux induces an electromotive force in the receiving coil, thereby transferring electrical energy to the load; the other is based on the principle of electric field coupling, where energy is transferred through the changing of two separable capacitor plates.

[0004] Resonant wireless power transfer technology can also be achieved through two principles: one is based on the principle of magnetic resonance, in which the transmitting coil and the receiving coil are in a self-resonant or resonant state in the near field, thereby realizing wireless power transfer over a medium distance; the other is based on the principle of electric field resonance, through which two inductive split capacitor plates are in a resonant state, realizing wireless power transfer.

[0005] The basic principle of microwave wireless power transmission technology is to transmit electrical energy into space in the form of microwaves through an antenna, and then convert the received energy into electrical energy to power the load, thereby realizing long-distance wireless power transmission.

[0006] Magnetic coupling mechanisms are key components for primary and secondary energy coupling in inductive wireless charging systems. Current research on magnetic coupling mechanisms mainly focuses on improving coupling capability, enhancing anti-offset capability, and reducing cost. Commonly used magnetic coupling mechanisms include solenoid coils, circular coils, and DD (double-D) coils. Solenoid coils have high magnetic leakage, which is not conducive to shielding and results in low magnetic field utilization. Circular coils improve system efficiency compared to solenoid coils and are easier to design, but the magnetic field height generated by circular coils is limited. DD coils, through opposite winding directions, increase the magnetic flux intensity at the center of the two coils, effectively increasing the magnetic field height and improving the anti-offset capability between the coils, but the charging area is limited. Summary of the Invention

[0007] To address the issue of decreased transmission efficiency caused by lateral displacement of the wireless charging coil, one objective of this invention is to propose a novel magnetic coupling mechanism that enables the system to maintain high-efficiency charging even after the receiving coil undergoes lateral displacement, and to achieve dynamic wireless charging for electric vehicles.

[0008] The technical solution adopted by this invention to solve its technical problem is: a novel magnetic coupling mechanism, comprising a W-shaped wireless charging coil, an interlaced magnetic core attached below the W-shaped wireless charging coil, and an aluminum plate placed at the bottom of the interlaced magnetic core as a substrate for the magnetic coupling mechanism. The W-shaped wireless charging coil is composed of two sets of overlapping multi-turn coils, namely, wireless charging coil one and wireless charging coil two. Wireless charging coil one and wireless charging coil two are multi-turn coils arranged in multiple columns. The plane is divided into multiple different closed rectangles by horizontal and vertical wiring. The closed rectangle formed by the two sets of multi-turn coils in space can be a rectangular charging area. In the domain, the magnetic flux of adjacent rectangular charging areas is a series magnetic flux, and the magnetic field strength of each rectangular charging area varies. When alternating current is passed through the two sets of multi-turn coil wires, alternating magnetic flux is generated in the rectangular charging area. The alternating magnetic flux passes through the secondary side receiving coil. Due to the principle of electromagnetic induction, an induced electromotive force is generated on the receiving coil, which then transfers energy from the primary side to the receiving coil, thereby transferring energy to the receiving circuit. The series magnetic flux enhances the strength of the magnetic field on the surface of the W-type wireless charging coil and also improves the anti-offset capability between the W-type wireless charging coil and the receiving coil. The interlaced magnetic core is composed of horizontally and vertically distributed strip magnetic cores.

[0009] The novel magnetic coupling mechanism described herein comprises two wireless charging coils, a first wireless charging coil and a second wireless charging coil, both having identical structures and similar shapes, forming an axisymmetric structure. Specifically, the first wireless charging coil is formed by extending a wire horizontally outward by one unit, then bending it 90° and extending it vertically outward by four units, then bending it 90° and extending it horizontally outward by one unit, then bending it 90° and extending it vertically inward by three units, and finally bending it 90° and extending it horizontally inward by two units. The second wireless charging coil is formed by extending a wire vertically outward by one unit, then bending it 90° and extending it horizontally outward by four units, then bending it 90° and extending it vertically outward by one unit, then bending it 90° and extending it horizontally inward by three units, and finally bending it 90° and extending it vertically inward by two units. The first and second wireless charging coils are arranged at a 90° angle to each other on an interlaced magnetic core, with the strip magnetic core forming a 45° angle with the horizontal / vertical direction of the wiring.

[0010] The novel magnetic coupling mechanism described herein has a core material including, but not limited to, manganese-zinc ferrite material with high magnetic permeability.

[0011] The second objective of this invention is to provide a multi-area inductive wireless charging system with a large charging range, strong anti-offset capability, and high energy transfer efficiency, so as to realize multi-load wireless charging.

[0012] The technical solution adopted by this invention to solve its technical problem is: a multi-load inductive wireless charging system, comprising a high-frequency inverter power supply and a primary-side first compensation circuit and a primary-side second compensation circuit respectively connected to the high-frequency inverter power supply. The primary-side first compensation circuit and the primary-side second compensation circuit are respectively connected to a wireless charging coil one and a wireless charging coil two of a novel magnetic coupling mechanism. The system also includes a receiving coil i (i=1, 2…), a secondary-side compensation circuit i (i=1, 2…), a rectifier and filter circuit i (i=1, 2…), and a load i (i=1, 2…) that form a magnetic field coupling with the wireless charging coil one and the wireless charging coil two. …), wherein the receiving coil i, the secondary compensation circuit i, the rectifier filter circuit i, and the load i are connected in sequence; the high-frequency inverter power supply outputs two high-frequency AC currents to the primary first compensation circuit and the primary second compensation circuit respectively. The wireless charging coil one and the wireless charging coil two are fed with high-frequency AC currents through the primary first compensation circuit and the primary second compensation circuit respectively. The alternating current generates a magnetic field that induces a current in the receiving coil i (i=1, 2…). The induced current then passes through the secondary compensation circuit i (i=1, 2…) and the rectifier circuit i (i=1, 2…) to charge the load i (i=1, 2…).

[0013] The multi-load inductive wireless charging system includes, but is not limited to, a series compensation circuit, a second primary compensation circuit, and a secondary compensation circuit.

[0014] The beneficial effects of this invention are:

[0015] The W-type wireless charging coil of the present invention forms multiple rectangular charging areas in a plane through horizontal and vertical wiring. The magnetic flux of adjacent rectangular charging areas is linked to form a series magnetic flux. The series magnetic flux increases the strength of the magnetic field on the surface of the W-type wireless charging coil and also improves the anti-offset capability between the W-type wireless charging coil and the receiving coil. When an alternating current is passed through the W-type wireless charging coil, an alternating magnetic flux is generated in the rectangular charging area, thereby transmitting energy to the receiving circuit.

[0016] The multi-load inductive wireless charging system of this invention can wirelessly charge multiple loads. Since the transmitting coil is a W-shaped wireless charging coil, which has multiple rectangular charging areas, the receiving coil can receive electrical energy in different rectangular charging areas. At the same time, it can power multiple loads, greatly improving the power supply range of wireless charging. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the novel magnetic coupling mechanism of the present invention;

[0018] Figure 2 Structural parameters for the W-type wireless charging coil;

[0019] Figure 3 and Figure 4 This is a schematic diagram of the charging current mode of the W-type wireless charging coil of the present invention;

[0020] Figure 5 This is a schematic diagram of the structure of the multi-load inductive wireless charging system of the present invention;

[0021] Figure 6 This is the equivalent circuit diagram of the novel magnetic coupling mechanism of the present invention;

[0022] Figure 7 The design process of the novel magnetic coupling mechanism of this invention is as follows;

[0023] Figure 8 and Figure 9 The magnetic field cloud diagram of the W-type wireless charging coil.

[0024] The attached figures are labeled as follows: 1—aluminum plate, 2—interlaced magnetic core, 31—wireless charging coil one, 32—wireless charging coil two. Detailed Implementation

[0025] This invention addresses the problem of decreased transmission efficiency caused by lateral offset of the wireless charging coil by proposing a novel magnetic coupling mechanism and a multi-load inductive wireless charging system.

[0026] Example 1

[0027] Reference Figure 1 As shown, this example presents a novel magnetic coupling mechanism, which includes a W-shaped wireless charging coil, an interleaved magnetic core 2, and an aluminum plate 1.

[0028] Reference Figure 2 As shown, the W-type wireless charging coil is composed of two sets of overlapping multi-turn coils, namely, wireless charging coil 31 and wireless charging coil 32. Wireless charging coil 31 and wireless charging coil 32 are arranged in multiple rows of multi-turn coils. The W-type wireless charging coil divides the plane into multiple different closed rectangles through horizontal and vertical wiring. The closed rectangles formed by the two sets of multi-turn coils in space can be considered rectangular charging areas. The magnetic flux of adjacent rectangular charging areas is series magnetic flux, and the magnetic field strength of each rectangular charging area varies. The series magnetic flux effectively enhances the magnetic field strength and improves the anti-offset capability between the W-type wireless charging coil and the receiving coil. When alternating current is passed through the two sets of multi-turn coil wires, alternating magnetic flux is generated in the rectangular charging area. The alternating magnetic flux passes through the secondary side receiving coil. Due to the principle of electromagnetic induction, an induced electromotive force is generated in the receiving coil, thereby transferring energy from the primary side to the receiving coil, and thus transferring energy to the receiving circuit.

[0029] The wireless charging coil 31 and wireless charging coil 32 have the same structure and similar shape. When viewed from a vertical plane, the two coils cannot be directly superimposed, and they are axially symmetrical structures.

[0030] The wiring of the wireless charging coil 31 is as follows: first, it extends horizontally outward by one unit; then, it bends 90° and extends vertically outward by four units; then, it bends 90° and extends horizontally outward by one unit; then, it bends 90° and extends vertically inward by three units; finally, it bends 90° and extends horizontally inward by two units. The wiring of the wireless charging coil 32 is as follows: first, it extends vertically outward by one unit; then, it bends 90° and extends horizontally outward by four units; then, it bends 90° and extends vertically outward by one unit; then, it bends 90° and extends horizontally inward by three units; finally, it bends 90° and extends vertically inward by two units.

[0031] Wireless charging coil 31 and wireless charging coil 32 are arranged at a 90° angle across the interlaced magnetic core 2. The strip magnetic core forms a 45° angle with the horizontal / vertical direction of the wiring. The strip magnetic core is placed diagonally according to the rectangular charging area of ​​the W-shaped wireless charging coil. The horizontal and vertical strip magnetic cores are arranged alternately below the W-shaped wireless charging coil. The interlaced magnetic core 2 has the characteristics of focusing magnetism and improving the magnetic circuit. The interlaced magnetic core 2 can improve the magnetic field distribution of the W-shaped wireless charging coil and improve the power transmission efficiency.

[0032] The interleaved magnetic core 2 is composed of strip magnetic cores distributed laterally and longitudinally, and the magnetic core material includes, but is not limited to, manganese-zinc ferrite material with high magnetic permeability.

[0033] The aluminum plate 1 is located at the bottom of the novel magnetic coupling mechanism. The aluminum plate 1 can shield high-frequency electric fields and electromagnetic radiation, reduce magnetic leakage in W-type wireless charging, and effectively reduce magnetic leakage, thereby improving magnetic field utilization. By adjusting the thickness of the aluminum plate 1, the coupling efficiency of the novel magnetic coupling mechanism can be improved.

[0034] Example 2

[0035] Another structure of this example, wireless charging coil 1 31 / wireless charging coil 2 32, has two modes according to the arrow direction: charging current mode 1 and charging current mode 2, as follows. Figure 3 and Figure 4 As shown.

[0036] In this diagram, V1 to V5 are column direction markers, and H1 to H5 are row direction markers. Viewed from a vertical plane, the W-shaped wireless charging coil divides its plane into 10 rectangular charging areas. Wireless charging coil 31 surrounds rectangular areas 1, 5, 6, and 7; wireless charging coil 32 surrounds rectangular areas 10, 8, 6, and 3. Rectangular area 6 is the overlapping area of ​​wireless charging coils 31 and 32. Rectangular areas 1, 3, 5, 6, 7, 8, and 10 form a closed rectangular area in space, which is defined as the rectangular charging area.

[0037] When two sets of multi-turn coils are supplied with currents of the same magnitude and phase, the W-type wireless charging coil operates in charging mode 1. According to Ampere's law, the magnetic flux direction at the center of the multiple rectangular charging regions is opposite to the magnetic flux direction of the adjacent rectangular charging regions along their diagonals; based on the flux continuity theorem, magnetic fluxes in opposite directions link together to form series flux. This series flux enhances the surface magnetic field strength of the W-type wireless charging coil and also improves the anti-misalignment capability between the W-type wireless charging coil and the receiving coil. Charging mode 1 is suitable for charging under conditions where multiple loads are powered and high charging power is required.

[0038] When the current phase of one of the multi-turn coils is reversed, the W-type wireless charging coil operates in charging mode 2. Due to structural symmetry, the magnetic field direction of the central rectangular charging area is opposite to that of the rectangular charging area at the input end. Charging mode 2 is suitable for charging under conditions with a small load and low charging power requirements.

[0039] Example 3

[0040] like Figure 5 As shown, the multi-load inductive wireless charging system proposed in this example consists of a high-frequency inverter power supply, a primary-side first compensation circuit, a primary-side second compensation circuit, a novel magnetic coupling mechanism, receiving coils i (i=1, 2…), secondary-side compensation circuits i (i=1, 2…), rectifier and filter circuits i (i=1, 2…), and loads i (i=1, 2…). The wireless charging coils 31 and 32 of the novel magnetic coupling mechanism form a magnetic field coupling with the receiving coil i. Because its transmitting coil is a W-type wireless charging coil, the receiving coil can receive electrical energy in different rectangular charging areas and provide reliable power to multiple loads simultaneously.

[0041] The high-frequency inverter power supply outputs two high-frequency AC currents to the primary side first compensation circuit and the primary side second compensation circuit. The primary side first compensation circuit is connected to the wireless charging coil 31, and the primary side second compensation circuit is connected to the wireless charging coil 32. The wireless charging coil 31 and the wireless charging coil 32 are respectively energized by the high-frequency AC current. Due to the magnetic field generated by the alternating current, an induced current is generated in the receiving coil i (i=1, 2...). The induced current then charges the load i (i=1, 2...) through the secondary side compensation circuit i (i=1, 2...) and the rectifier circuit i (i=1, 2...).

[0042] The multi-load inductive wireless charging system is suitable for charging multiple loads simultaneously, improving load utilization. The high-frequency inverter power supply can generate two sets of currents with different phases at the same time. After passing through the primary side first compensation circuit and the primary side second compensation circuit, the two sets of currents flow to the W-type wireless charging coil. The current flowing through the W-type wireless charging coil generates magnetic flux in different directions in the rectangular charging area it forms.

[0043] When the W-type wireless charging coil operates in charging current mode 1, the high-frequency inverter power supply inputs two currents with the same amplitude, frequency, and phase from V1 and H5 respectively, supplying wireless charging coil 31 and wireless charging coil 32. Viewed from the perspective of the vertical plane of the paper, the direction of the "spatial current" in rectangular charging areas 1, 3, and 8 is counterclockwise, while in rectangular charging areas 5, 7, and 10 it is clockwise. According to Ampere's law, the counterclockwise "spatial current" generates a magnetic flux perpendicular to the paper and outwards, while the clockwise "spatial current" generates a magnetic flux perpendicular to the paper and inwards. According to the continuity theorem of magnetic flux, the magnetic fluxes in opposite directions in adjacent rectangular charging areas of the W-type wireless charging coil will link together to form a series magnetic flux, resulting in a denser magnetic field near the coil surface. This series magnetic flux enhances the magnetic flux intensity on the surface of the W-type wireless charging coil, improving the lateral anti-offset capability of the receiving coil.

[0044] When the W-type wireless charging coil operates in charging current mode 2, the high-frequency inverter output current... Phase and output current The phase difference is 180°. and The current flows into wireless charging coil 31 and wireless charging coil 32 respectively. Viewed from a perpendicular angle to the paper, the direction of the "spatial current" in the W-shaped wireless charging coils is counter-clockwise in rectangular charging areas 1 and 3, and clockwise in rectangular charging area 6. Similarly, the magnetic flux generated by the "spatial current" in rectangular charging areas 1, 3, and 6 is interconnected, allowing the receiving coil to be charged within this area.

[0045] The current direction of the W-type wireless charging coil can be adjusted according to the actual load quantity and location requirements, so that the W-type wireless charging coil can work in charging current mode 1 or charging current mode 2.

[0046] Reference Figure 6 As shown, L1 and L2 are coil structure parameters, and D1 and D2 are shape parameters of wireless charging coil 31 and wireless charging coil 32, respectively, with D1=D2. The structure and shape parameters of the W-type wireless charging coil can be designed according to actual engineering needs.

[0047] To simplify circuit analysis, the primary-side first compensation circuit, the primary-side second compensation circuit, and the secondary-side compensation circuit are all connected in series. Based on frequency domain steady-state circuit analysis theory, We can obtain:

[0048] .

[0049] .

[0050] .

[0051] .

[0052] Load power is expressed as .

[0053] Efficiency is expressed as .

[0054] Mutual inductance is represented as and .

[0055] From the load power formula, we can know , These are parameters related to the structure of the magnetic coupling mechanism, depending on the input power supply voltage. resonant frequency Once determined, the load power and efficiency depend only on the structural parameters of the magnetic coupling mechanism. From the mutual inductance formula, mutual inductance is defined as the length of the magnetic flux passing through the magnet divided by the excitation current. The equivalent circuit diagram of the novel magnetic coupling mechanism of this invention is shown below. Figure 6 As shown.

[0056] The design process of the novel magnetic coupling mechanism of this invention is as follows: Figure 7 As shown, N1 and N2 are the number of turns of wireless charging coil 31 and wireless charging coil 32, respectively. The specific steps are as follows.

[0057] a. Set the primary-side compensation method. The primary-side compensation circuit includes, but is not limited to, series compensation circuit and parallel compensation circuit.

[0058] b. Then, given the structural parameters L1, L2, D1, and D2 of the W-type wireless charging coil, determine whether the charging area meets the requirements. If the charging area does not meet the design requirements, modify the W-type wireless charging coil parameters L1, L2, D1, and D2 until the design requirements of the charging area are met.

[0059] c. Determine if the output power meets the design requirements. If it does not meet the requirements, a magnetic core can be added. If it meets the requirements, proceed to the next step.

[0060] d, Set output , and M can be calculated and compared with the target value M0. If the value of M does not meet the requirements, the value of M can be increased by increasing the number of turns. If the value of M meets the requirements, proceed to the next step.

[0061] e, calculated according to the load power formula and and compare it with the target value and The comparison is performed. If the design requirements are not met, step d is repeated until the design requirements are met, thus completing the design of the magnetic coupling mechanism.

[0062] The magnetic field cloud diagram of the W-shaped wireless charging coil is as follows: Figure 8 and Figure 9 As shown, when the W-type wireless charging coil is operating in charging mode 1, the magnetic field cloud diagram is as follows. Figure 8 As shown, the magnetic field strength is relatively high in rectangular charging areas 1, 3, 5, 7, 8, and 10, allowing multiple loads to be charged simultaneously in these areas. When the W-type wireless charging coil operates in charging mode 2, the magnetic field cloud map is as follows. Figure 9 As shown, the magnetic field strength of rectangular charging area 5 is relatively large, which can supply power to the load located in rectangular charging area 5 alone. The magnetic field strength of other rectangular charging areas is weakened, and the loads located in other rectangular charging areas can reduce the charging power.

[0063] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some of the application examples. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A novel magnetic coupling mechanism, characterized in that: The device includes a W-shaped wireless charging coil, an interlaced magnetic core (2) attached to the bottom of the W-shaped wireless charging coil, and an aluminum plate (1) placed at the bottom of the interlaced magnetic core (2). The W-shaped wireless charging coil is composed of an overlapping wireless charging coil one (31) and a wireless charging coil two (32). The wireless charging coil one (31) and the wireless charging coil two (32) form several rectangular charging areas through horizontal and vertical wiring. The magnetic flux of adjacent rectangular charging areas is a series magnetic flux. The magnetic field strength of each rectangular charging area is different. The interlaced magnetic core (2) is composed of horizontal and vertical interlaced bar magnetic cores.

2. The novel magnetic coupling mechanism according to claim 1, characterized in that, The wireless charging coil one (31) and wireless charging coil two (32) have the same structure and similar shape.

3. A novel magnetic coupling mechanism according to claim 1 or 2, characterized in that, The wireless charging coil one (31) is formed by extending the wire horizontally outward by one unit, then turning it 90° and extending it vertically outward by four units, then turning it 90° and extending it horizontally outward by one unit, then turning it 90° and extending it vertically inward by three units, and finally turning it 90° and extending it horizontally inward by two units. The wireless charging coil two (32) is formed by extending the wire vertically outward by one unit, then turning it 90° and extending it horizontally outward by four units, then turning it 90° and extending it vertically outward by one unit, then turning it 90° and extending it horizontally inward by three units, and finally turning it 90° and extending it vertically inward by two units. The wireless charging coil one (31) and the wireless charging coil two (32) are arranged at a 90° angle on the interlaced magnetic core (2), and the strip magnetic core is at a 45° angle to the wiring direction.

4. A novel magnetic coupling mechanism according to claim 3, characterized in that, The magnetic core uses manganese-zinc ferrite material.

5. A multi-load inductive wireless charging system, characterized in that, The device includes a high-frequency inverter power supply and a transmitting coil connected to the high-frequency inverter power supply through a primary-side first compensation circuit and a primary-side second compensation circuit, respectively. It also includes n receiving coils that form a magnetic field coupling with the transmitting coils, where n≥1. The receiving coils are connected to the secondary-side compensation circuit and the rectifier filter circuit in sequence before being connected to the load. The transmitting coils are the wireless charging coil one (31) and wireless charging coil two (32) of the novel magnetic coupling mechanism described in claim 1. The high-frequency inverter power supply outputs two high-frequency AC currents to the primary-side first compensation circuit and the primary-side second compensation circuit, respectively. The magnetic field is generated by the wireless charging coil one (31) and the wireless charging coil two (32), and the receiving coil generates an induced current, which is then charged to the load through the secondary-side compensation circuit and the rectifier circuit.

6. A multi-load inductive wireless charging system according to claim 5, characterized in that, The primary-side first compensation circuit, the primary-side second compensation circuit, and the secondary-side compensation circuit are either series compensation circuits or parallel compensation circuits.

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