Solenoid magnetic coupling mechanism for atmospheric air gap wireless charging and manufacturing method

Abstract

The application discloses a solenoid magnetic coupling mechanism for atmospheric gap wireless charging and a manufacturing method thereof, comprising a transmitting end and a receiving end; the transmitting end comprises a transmitting coil and a transmitting end magnetic core, the transmitting coil is tightly wound on the transmitting end magnetic core, and the transmitting end magnetic core is in the shape of a Chinese character 'ri'; the receiving end comprises a receiving coil and a receiving end magnetic core, the receiving coil is tightly wound on the receiving end magnetic core, and the receiving end magnetic core is in the shape of a Chinese character 'ri'; the transmitting coil comprises a plurality of sub-coils, the current directions of the sub-coils are the same, and the magnetic fields generated by the sub-coils are superposed at the receiving coil. The magnetic coupling mechanism has a large transmission distance and good anti-offset performance, and can be used in occasions with a large atmospheric gap and high anti-offset performance requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of wireless power transmission, and particularly relates to a solenoid magnetic coupling mechanism for large air gap wireless charging and a manufacturing method thereof. BACKGROUND

[0002] Wireless power transmission refers to a kind of energy transmission technology that transmits energy from a power supply side to a power utilization device in a non-direct contact manner, breaks the shackles of traditional charging methods such as wires and cables, has better adaptability and safety, and is widely concerned and researched by domestic and foreign scholars as a new charging method. The coupling mechanism is a key part of energy transmission in a wireless power transmission system. High-frequency alternating current is converted into a high-frequency magnetic field through a transmitting coil, the high-frequency magnetic field is converted into the same frequency alternating current through a receiving coil, the electric energy is transmitted to a load after processing, and wireless transmission of energy is realized.

[0003] The existing magnetic coupling mechanism of the wireless power transmission system focuses on the improvement of transmission efficiency and output power, but the transmission distance is mostly concentrated in about 300mm. When the air gap of the magnetic coupling mechanism continues to increase, the coupling coefficient and mutual inductance decrease substantially, and the anti-deviation ability is weak. SUMMARY

[0004] The purpose of the present application is to provide a solenoid magnetic coupling mechanism for large air gap wireless charging and a manufacturing method thereof, which can improve the anti-deviation ability of the wireless charging system and solve the problem of small transmission distance of the existing magnetic coupling mechanism.

[0005] The solenoid magnetic coupling mechanism for large air gap wireless charging of the present application comprises a transmitting end and a receiving end. The transmitting end comprises a transmitting coil and a transmitting end magnetic core, and the transmitting coil is tightly wound on the transmitting end magnetic core. The transmitting end magnetic core is in the shape of a Chinese character 'Ri'. The receiving end comprises a receiving coil and a receiving end magnetic core, and the receiving coil is tightly wound on the receiving end magnetic core. The receiving end magnetic core is in the shape of a Chinese character 'Ri'. The transmitting coil comprises a plurality of sub-coils, the current directions of the sub-coils are the same, and the magnetic fields generated by the sub-coils are superposed at the receiving coil.

[0006] The transmitting coil comprises three sub-coils, the three sub-coils are centrally distributed on the three horizontal edges of the transmitting end magnetic core, and are wound along the horizontal edges in a spiral manner. The receiving coil comprises three sub-coils, the three sub-coils are centrally distributed on the three horizontal edges of the receiving end magnetic core, and are wound along the horizontal edges in a spiral manner. The magnetic coupling mechanism is axially symmetrical as a whole.

[0007] The central axis of the transmitting coil, the central axis of the transmitting end magnetic core, the central axis of the receiving coil and the central axis of the receiving end magnetic core are coaxially arranged, which is the optimal alignment position, and the wireless charging efficiency is the highest at this time.

[0008] The sub-coils of the transmitting coil and the receiving coil are wound in the same direction and in series by using the same wire, so that exposed wire interfaces are avoided and additional loss at the wire connection is avoided.

[0009] The transmitting end magnetic core and the receiving end magnetic core are in the shape of a long rectangular ferrite material, so that compared with a traditional magnetic core setting method, material is saved and heat dissipation is facilitated.

[0010] The three horizontal edges of the transmitting end magnetic core and the receiving end magnetic core have the same width as the horizontal edge gap width of the magnetic core, so that the design process is simplified.

[0011] The horizontal edge gap length of the transmitting end magnetic core and the receiving end magnetic core is smaller than the length of the magnetic core and greater than the length of the corresponding coil along the corresponding horizontal edge of the magnetic core, so that compared with a traditional magnetic core setting method, the magnetic concentration effect is improved.

[0012] The number of turns of each sub-coil included in the transmitting coil and the receiving coil is equal, so that the symmetry design is more conducive to obtaining a uniform magnetic field.

[0013] The application also includes a manufacturing method of the solenoid magnetic coupling mechanism for the atmospheric gap wireless charging, and the manufacturing method includes the following steps:

[0014] (I) determine the coupling mechanism air gap, that is, the transmission distance and the output power, set the initial value L0 of the magnetic core length, the initial value W0 of the magnetic core width, and set the magnetic core thickness as a fixed value;

[0015] (II) the size setting method of the transmitting coil and the receiving coil is consistent, the initial value of the width of the two ends of the transmitting coil and the receiving coil magnetic core is W 20 , the initial value of the coil length is L 10 , the number of turns of the coil is obtained from the coil length;

[0016] (III) use finite element simulation software to perform parameterized simulation on the coupling mechanism to obtain the coupling mechanism parameters of the magnetic core length L, the magnetic core width W, the width W2 of the two ends of the magnetic core and the coil length L1 that meet the constraint conditions.

[0017] In step (III), the constraint condition is set as:

[0018]

[0019] W = 5W1

[0020] L1 < L - 2W2 < L (W2 > 0)

[0021] In the formula, P out0 represents the minimum output power; V imrepresents the maximum input voltage; R1, R2 respectively represent the equivalent resistance of the transmitting coil and the receiving coil; I1, I2 respectively represent the current flowing through the transmitting end and the receiving end; R L represents the load resistance; M represents the mutual inductance between the receiving coil and the transmitting coil.

[0022] Beneficial effects: compared with the prior art, the technical scheme of the present application has the beneficial effects that the magnetic field generated by each sub-coil of the transmitting coil can be superimposed and enhanced at the receiving coil, and a higher magnetic flux path is generated, so that a greater transmission distance can be achieved, the coupling strength of the coupling mechanism is improved, and the coupling mechanism has higher anti-offset performance. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of the present application;

[0024] Figure 2 is Figure 1 is a structural schematic diagram of the magnetic core;

[0025] Figure 3 is a simplified circuit diagram of the wireless charging of the present application;

[0026] Figure 4 is a coupling coefficient offset characteristic curve diagram of the present application;

[0027] Figure 5 is a coupling coefficient retention rate change curve diagram with offset of the present application. DETAILED DESCRIPTION

[0028] The technical scheme of the present application will be described in detail below in combination with specific embodiments and the accompanying drawings of the specification.

[0029] For example, Figure 1 and Figure 2As shown in the figure, the magnetic coupling mechanism of the present invention includes a transmitting end and a receiving end. The receiving end is opposite to the transmitting end and is located at a height h directly above the receiving end. The transmitting end includes a transmitting coil 2 and a transmitting core 1. The transmitting coil 2 is closely wound around the transmitting core 1, and the transmitting core 1 is in the shape of a Chinese character 'Ri'; specifically, the transmitting coil 2 includes three sub-coils, and the three sub-coils are centrally distributed on the three horizontal sides of the transmitting core 1 and are wound in a spiral manner along the horizontal sides. The receiving end includes a receiving coil 3 and a receiving core 4. The receiving coil 3 is closely wound around the receiving core 4, and the receiving core 4 is in the shape of a Chinese character 'Ri'; specifically, the receiving coil 3 includes three sub-coils, and the three sub-coils are centrally distributed on the three horizontal sides of the receiving core 4 and are wound in a spiral manner along the horizontal sides. The number of turns of each sub-coil included in the transmitting coil 2 is equal, and the number of turns of each sub-coil included in the receiving coil 3 is equal. The magnetic coupling mechanism is axially symmetric as a whole. In this embodiment, the central axes of the transmitting coil 2, the transmitting core 1, the receiving coil 3, and the receiving core 4 are coaxially arranged, which is the optimal alignment position, and the wireless charging efficiency is the highest at this time. The sub-coils of the transmitting coil 2 and the receiving coil 3 are wound in series in the same direction using the same wire, which can avoid generating exposed wire interfaces and avoid additional losses at the wiring points. The transmitting core 1 and the receiving core 4 are both made of ferrite materials in the shape of a rectangular parallelepiped with a Chinese character 'Ri'. The widths of the three horizontal sides of the transmitting core 1 and the receiving core 4 are equal to the widths of the gaps between their core horizontal sides. The lengths of the gaps between the core horizontal sides of the transmitting core 1 and the receiving core 4 are less than their core lengths and greater than the lengths of the corresponding coils along the corresponding core horizontal sides.

[0030] The present invention also includes a manufacturing method for a magnetic coupling mechanism of a Chinese character 'Ri' solenoid for air-gap wireless charging. The manufacturing method includes the following steps:

[0031] (1) Determine the transmission distance and output power, and determine the initial value L0 of the core length, the initial value W0 of the core width, and set the core thickness to a fixed value of 10 mm according to the transmission distance and output power level;

[0032] (2) Keep the size setting methods of the transmitting coil and the receiving coil consistent, set the initial value W 20 of the widths at both ends of the transmitting and receiving coil cores, and the initial value L 10 of the coil length, and obtain the number of turns of the coil from the coil length;

[0033] (3) Use the finite element simulation software ANSYS Maxwell to perform parametric simulation on the coupling mechanism, and obtain the coupling mechanism parameters of the core length L, the core width W, the widths W2 at both ends of the core, and the coil length L1 that meet the conditions, and the constraint conditions are set as:

[0034]

[0035] W = 5W1

[0036] L1 < L-2W2 < L (W2 > 0)

[0037] In the formula, P out0 represents the minimum output power; V im represents the maximum input voltage; R1 and R2 respectively represent the equivalent resistance of the transmitting coil and the receiving coil; I1 and I2 respectively represent the current flowing through the transmitting end and the receiving end; R L represents the load resistance; M represents the mutual inductance between the receiving coil and the transmitting coil.

[0038] The present scheme will be described below in combination with specific embodiments.

[0039] Assuming that the size of the magnetic core is 1000mm*1000mm*10mm, the distance between the transmitting coil and the receiving coil is 500mm, the control rectangular DD coil and the litz wire used by the magnetic coupling mechanism of the present application are the same and have equal length, and the remaining conditions are the same. Experiments are respectively conducted on the two coupling mechanisms, the receiving end is offset along the Y-axis direction, and the coupling coefficient and the coupling coefficient retention rate of the two magnetic coupling mechanisms are obtained. The variation curve of the offset is shown in Figure 4 and Figure 5 The coupling coefficient retention rate is defined.

[0040]

[0041] In the formula: k h is the coupling coefficient retention rate; k m is the coupling coefficient after offset; k0 is the coupling coefficient when the coils are directly opposite. It can be known from Figure 4 and Figure 5 that under the condition that other conditions are the same, the coupling coefficients of the present application before and after offset are both greater than the DD coil, and the coupling coefficient retention rate of the present application under the same offset condition is also relatively optimal, that is, it is explained that based on the structure of the present application, the receiving coil moves within the offset range, the coupling effect of the coupling mechanism is still good, the working state of the system is more stable, and the anti-offset performance is better.

Claims

1. A solenoid magnetic coupling mechanism for atmospheric air gap wireless charging, comprising a transmitting end and a receiving end; characterized in that: The transmitting end comprises a transmitting coil (2) and a transmitting end magnetic core (1), the transmitting coil (2) is tightly wound on the transmitting end magnetic core (1), and the transmitting end magnetic core (1) is a sun-shaped type; the receiving end comprises a receiving coil (3) and a receiving end magnetic core (4), the receiving coil (3) is tightly wound on the receiving end magnetic core (4), and the receiving end magnetic core (4) is a sun-shaped type; The transmitting coil (2) comprises a plurality of sub-coils, the current directions of the sub-coils are the same, and the magnetic fields generated by the sub-coils are superposed at the receiving coil (3); The transmitting coil (2) comprises three sub-coils, the three sub-coils are distributed on the three horizontal edges of the transmitting end magnetic core (1) in the middle, and are wound along the horizontal edges in a spiral manner; the receiving coil (3) comprises three sub-coils, the three sub-coils are distributed on the three horizontal edges of the receiving end magnetic core (4) in the middle, and are wound along the horizontal edges in a spiral manner, and the magnetic coupling mechanism is axially symmetrical as a whole.

2. The solenoid magnetic coupling mechanism for atmospheric air gap wireless charging of claim 1, wherein: The central axis of the transmitting coil (2), the central axis of the transmitting end magnetic core (1), the central axis of the receiving coil (3) and the central axis of the receiving end magnetic core (4) are coaxially arranged.

3. The solenoid magnetic coupling mechanism for atmospheric air gap wireless charging of claim 1, wherein: The sub-coils of the transmitting coil (2) and the receiving coil (3) are wound in the same direction by using the same wire in series.

4. The solenoid magnetic coupling mechanism for atmospheric air gap wireless charging of claim 1, wherein: The transmitting end magnetic core (1) and the receiving end magnetic core (4) are both sun-shaped cuboid ferrite materials.

5. The solenoid magnetic coupling mechanism for atmospheric air gap wireless charging of claim 1, wherein: The widths of the three horizontal edges of the transmitting end magnetic core (1) and the receiving end magnetic core (4) are equal to the gap widths of the horizontal edges of the magnetic cores.

6. The solenoid magnetic coupling mechanism for atmospheric air gap wireless charging of claim 1, wherein: The gap lengths of the horizontal edges of the transmitting end magnetic core (1) and the receiving end magnetic core (4) are less than the lengths of the magnetic cores, and are greater than the lengths of the corresponding coils along the corresponding horizontal edges of the magnetic cores.

7. The solenoid magnetic coupling mechanism for atmospheric air gap wireless charging of claim 1, wherein: The numbers of turns of the sub-coils of the transmitting coil (2) and the receiving coil (3) are equal.

8. A method of fabricating the solenoid magnetic coupling mechanism for atmospheric air-gap wireless charging of claim 1, wherein, The manufacturing method comprises the following steps: (1) determining the air gap of the coupling mechanism, i.e. the transmission distance and the output power, setting the initial value L0 of the length of the magnetic core, the width W0 of the magnetic core, and setting the thickness of the magnetic core as a fixed value; (ii) the size setting method of the transmitting coil and the receiving coil is consistent, the initial value of the width of the two ends of the magnetic core of the transmitting coil and the receiving coil is W 20 , and the initial value of the length of the coil is L 10 , the number of turns of the coil is obtained from the length of the coil; (3) performing parameterized simulation on the coupling mechanism by using a finite element simulation software, and obtaining the parameters of the coupling mechanism, i.e. the length L of the magnetic core, the width W of the magnetic core, the width W2 of the two ends of the magnetic core and the length L1 of the coil, which satisfy the constraint conditions.

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