Magnetic coupling structure with anti-offset characteristic, method and wireless power transmission system

Abstract

The invention discloses a magnetic coupling structure with an anti-offset characteristic, a method and a wireless power transmission system. The magnetic coupling structure comprises a transmitting end and a receiving end, a receiving coil is of an axial symmetry structure and is divided into an inner receiving coil and an outer receiving coil, and the outer receiving coil is formed by sequentially connecting four sub-coils with the same size in series; the four sub-coils are arranged along the circumference and define an inner receiving coil placing area, an inner receiving coil is arranged in the inner receiving coil placing area, and the inner receiving coil and the outer receiving coil can be decoupled mutually due to the winding mode and the space structure of the inner receiving coil and the outer receiving coil. When the receiving end and the transmitting end generate relative position offset, the mutual inductance fluctuation of the system can be maintained in a small range. According to the wireless electric energy transmission system formed by the magnetic coupling structure, an LCC-S compensation topological structure is adopted, the inner receiving coil and the outer receiving coil are connected in series after passing through respective full-bridge rectifier filters, voltage output superposition complementation can be achieved, and the stability of the total output voltage is guaranteed.

Description

Technical Field

[0001] The invention relates to a magnetic coupling structure in the technical field of wireless power transmission, and in particular to a magnetic coupling structure with anti-deviation characteristics, a design method and a wireless power transmission system composed of the magnetic coupling structure. Background Art

[0002] Wireless Power Transfer (WPT) technology eliminates the rigid need for cables in traditional wired charging technology, completely revolutionizing the charging method, and can achieve energy transmission simply by relying on the mutual coupling between the transmitting coil and the receiving coil. This technology is not only convenient, but also avoids the exposure and aging of wires, further improving safety. As the potential of WPT technology is continuously explored, it has been widely used in electric vehicles, consumer electronics, smart homes, medical equipment and other fields.

[0003] In the actual application of wireless power transmission, since the energy transceiver coils cannot be completely aligned, there will be a position offset between the receiving coil and the transmitting coil. The coupling coefficient of the wireless charging system will change significantly with the change of the coil position offset, resulting in instability of the system output voltage. Therefore, the current research focus of WPT is mainly on improving the system's anti-offset capability.

[0004] At present, the improvement of the system's anti-offset capability mainly includes three aspects: magnetic coupling structure design, compensation topology design and power control.

[0005] The magnetic coupling structure design can be achieved by optimizing the combination design of some classic coils such as circular coil (Circular Pad, CP), double D coil (Double D Pad, DDP), bipolar coil (Bipolar Pad, BP), etc., or designing a new structure based on the original structure. However, these additional structures will increase the volume of the coil and the amount of copper wire used.

[0006] The compensation topology design is generally an improved design based on the four basic topologies. The mixed compensation topology can achieve different effects. For example, the double-sided inductor-capacitor-capacitor (LCC-LCC) can achieve constant current output, and the inductance-double capacitors-series (LCC-S) can achieve constant voltage output. These topologies can be selected according to actual needs, but the number of energy storage components will increase to a certain extent.

[0007] There are three main types of power control: secondary side control that adds a DC-DC converter on the secondary side, primary side control that requires a feedback communication circuit, and bilateral control that combines the two. However, all three situations undoubtedly increase the complexity of the system.

[0008] In WPT systems, the design of magnetic coupling structures plays a dominant role, and the quality of the design directly affects the coupling performance and transmission efficiency of the system. Therefore, it is necessary to propose a magnetic coupling structure with better performance. Summary of the invention

[0009] In order to solve the technical problems faced by the current wireless power transmission system, the present invention aims to construct a magnetic coupling structure with anti-drift characteristics and a wireless power transmission system composed of the structure. The magnetic coupling structure not only enables the WPT system to have a strong anti-drift capability, but also effectively realizes the system's stable control of the output voltage. The present invention avoids the defects of increasing the system volume and the amount of copper wire used by simply adding a coil structure, and at the same time combines the LCC-S compensation topology to achieve stable voltage and power output, without the need to introduce additional power control circuits, reducing the complexity of the system.

[0010] In order to overcome the above technical difficulties, the technical solution adopted by the present invention is:

[0011] 1. A magnetic coupling structure with anti-offset characteristics

[0012] The magnetic coupling structure includes a transmitting end and a receiving end, wherein the transmitting end includes a transmitting coil; the receiving end includes a receiving coil, and the receiving coil includes an inner receiving coil and an outer receiving coil. The inner receiving coil is arranged inside the outer receiving coil, and the transmitting coil is coupled with the inner receiving coil and the outer receiving coil.

[0013] The receiving coil is an axisymmetric structure, and the outer receiving coil is composed of four sub-coils of the same size connected in series in sequence; the four sub-coils are arranged along the circumference and the four sub-coils surround an inner receiving coil placement area, and the inner receiving coil is arranged in the inner receiving coil placement area.

[0014] Among the four sub-coils, two sub-coils are wound in a clockwise direction, and the other two sub-coils are wound in a counterclockwise direction. The four sub-coils are connected in a "clockwise-counterclockwise-counterclockwise" manner.

[0015] The inner receiving coil is circular or square.

[0016] The transmitting end further includes a primary magnetic core, and the receiving end further includes a secondary magnetic core. The primary magnetic core is located on the surface of the transmitting coil away from the receiving coil, and the secondary magnetic core is located on the surface of the receiving coil away from the transmitting coil.

[0017] 2. A design method for a magnetic coupling structure with anti-offset characteristics

[0018] S1: Determine the external length L1, external width W1, external length L2 and external width W2 according to the actual application scenario; and determine the air gap distance H between the transmitting end and the receiving end;

[0019] S2: Set the number of turns of the transmitting coil N T , receiving the number of turns of the outer coil N out , receiving inner coil length L3, receiving inner coil width W3, receiving inner coil turns N in The upper and lower limits and initial value of

[0020] S3: Determine the mutual inductance M between the transmitting coil and the external receiving coil through simulation TR1 And the mutual inductance M between the transmitting coil and the internal receiving coil TR2 , according to the mutual inductance M between the transmitting coil and the external receiving coil TR1 and the mutual inductance M between the transmitting coil and the internal receiving coil TR2 Determine the total mutual inductance M TR ;

[0021] S4: Simulate the mutual inductance fluctuation ΔM under offset state through simulation TR , thereby generating a set of design parameters;

[0022] S5: Re-adjust the number of turns N of the transmitting coil T , receiving the number of turns of the outer coil N out , receiving inner coil length L3, receiving inner coil width W3, receiving inner coil turns N in , repeat S3 and S4 to obtain multiple sets of design parameters;

[0023] S6: Select the mutual inductance fluctuation ΔM TR The lowest design parameters and calculate the corresponding inductance L of the transmitting coil T , the inductance of the external receiving coil L R1 and the inductance L of the inner receiving coil R2 , completing the design of the magnetic coupling structure.

[0024] The S4 is specifically:

[0025] The total mutual inductance M within the offset range is simulated by simulation TR And calculate the mutual inductance fluctuation ΔM TR , determine the mutual inductance fluctuation ΔM TR Whether it exceeds the first preset threshold, if it exceeds, the receiving inner coil length L3 and the receiving inner coil width W3 are increased and adjusted, if it does not exceed, the mutual inductance fluctuation ΔM is continued to be determined TR Whether it exceeds the second preset threshold, if it exceeds, the number of turns N of the receiving inner coil is inTake the increase adjustment, if it does not exceed, continue to judge the mutual inductance fluctuation ΔM TR Whether it exceeds the third preset threshold, if it exceeds, the number of turns N of the receiving outer coil is out and the number of turns of the transmitting coil N T Take increasing adjustment until the mutual inductance fluctuation ΔM TR If it is lower than the third preset threshold, the current number of turns of the transmitting coil N is recorded. T , receiving the number of turns of the outer coil N out , receiving inner coil length L3, receiving inner coil width W3, receiving inner coil turns N in and as a set of design parameters.

[0026] 3. A wireless power transmission system composed of a magnetic coupling structure with anti-deviation characteristics

[0027] The wireless power transmission system includes the transmitting end and the receiving end; the transmitting end includes a DC voltage source, an inverter circuit and a primary resonant circuit, the primary resonant circuit includes a connected transmitting coil and a primary compensation network, the receiving end includes an internal resonant circuit of the secondary side, the external resonant circuit of the secondary side, an internal full-bridge rectifier filter circuit of the secondary side, an external full-bridge rectifier filter circuit of the secondary side and a resistive load, the internal resonant circuit of the secondary side includes a connected internal receiving coil and a first secondary compensation network, and the external resonant circuit of the secondary side includes a connected external receiving coil and a second secondary compensation network; the internal full-bridge rectifier filter circuit of the secondary side and the external full-bridge rectifier filter circuit of the secondary side are connected in series to form a complete secondary rectifier filter circuit.

[0028] The value of the DC voltage source V IN The formula is as follows:

[0029]

[0030] Among them, U IN is the voltage after the DC voltage source is inverted;

[0031] The voltage U after the DC voltage source is inverted IN The formula is as follows:

[0032]

[0033] Among them, M TR is the total mutual inductance of the transmitting coil and the receiving coil, ω is the resonant angular frequency of the wireless power transmission system working in a resonant state, R TC is the compensation inductance L TC The resistance value, R T is the equivalent resistance of the primary receiving coil, R R is the equivalent resistance of the secondary receiving coil, R E is the resistive load RL The equivalent resistance, U R is the equivalent resistance R E Fundamental voltage on R R1 is the resistance value of the secondary outer receiving coil winding, R R2 is the resistance value of the receiving coil winding within the secondary side, V R is the output voltage.

[0034] The primary compensation network adopts an LCC compensation topology, and the first secondary compensation network and the second secondary compensation network both adopt an S-type compensation topology.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention provides a magnetic coupling structure with anti-deviation characteristics, wherein the structure of the outer receiving coil of the receiving coil surrounding the inner receiving coil reduces the space occupancy rate and realizes the mutual decoupling of the inner and outer receiving coils due to the winding method and the spatial structure, and when the receiving coil and the transmitting coil are offset, the total mutual inductance M of the system can be maintained. TR And the mutual inductance fluctuation ΔM TR Keep it within a small range, thereby improving the anti-deviation ability of the wireless power transmission system.

[0037] The present invention provides a wireless power transmission system composed of a magnetic coupling structure with anti-offset characteristics. The magnetic coupling structure is adopted in combination with an LCC-S compensation topology network, and the series connection of internal and external receiving coils is realized by a full-bridge rectifier filter, thereby realizing the superposition and complementarity of the output voltage, maintaining the total output voltage fluctuation within a small range, and further improving the transmission stability of the wireless power transmission technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a stereoscopic diagram of a magnetic coupling structure provided by an example of the present invention.

[0039] Figure 2 It is an exploded view of a receiving coil of a magnetic coupling structure provided in an example of the present invention.

[0040] Figure 3 It is a planar structure and winding diagram of a transmitting coil of a magnetic coupling structure provided by an example of the present invention.

[0041] Figure 4 It is a planar structure and winding diagram of a receiving coil of a magnetic coupling structure provided by an example of the present invention.

[0042] Figure 5 It is a parameter optimization design flow chart of the magnetic coupling structure provided by the example of the present invention.

[0043] Figure 6It is a circuit topology diagram of a wireless power transmission system composed of a magnetic coupling structure provided in an example of the present invention.

[0044] Figure 7 It is an equivalent circuit diagram of a wireless power transmission system provided by an example of the present invention.

[0045] Figure 8 It is a curve diagram of the X / Y direction offset mutual inductance change of the wireless power transmission system provided by an example of the present invention.

[0046] Fig. 9 Schematic diagram of the transmitter end of the wireless power transmission system.

[0047] Fig.10 Schematic diagram of the receiving end of the wireless power transmission system.

[0048] Fig.11 Schematic diagram of some shapes of inner and outer receiving coils.

[0049] In the figure: 1, transmitting coil, 2, primary magnetic core, 3, receiving coil, 4, secondary magnetic core, 5, inner receiving coil, 6, outer receiving coil. DETAILED DESCRIPTION

[0050] The present invention is described in detail below in conjunction with the accompanying drawings.

[0051] On the one hand, the present invention proposes a magnetic coupling structure with anti-offset characteristics, the magnetic coupling structure includes a transmitting end and a receiving end, the transmitting end includes a transmitting coil 1; the receiving end includes a receiving coil 3, the receiving coil 3 includes an inner receiving coil 5 and an outer receiving coil 6, the inner receiving coil 5 is arranged inside the outer receiving coil 6 and is arranged centrally, and the transmitting coil 1 is coupled with the inner receiving coil 5 and the outer receiving coil 6.

[0052] The receiving coil 3 is an axisymmetric structure, and the outer receiving coil 6 is composed of four sub-coils of the same size connected in series in sequence; the four sub-coils are arranged along the circumference and the four sub-coils surround an inner receiving coil placement area, and the inner receiving coil 5 is arranged at the center of the inner receiving coil placement area, and the outermost sides of the inner receiving coil 5 are close to the corresponding sides of the four sub-coils. Among the four sub-coils, the winding direction of two sub-coils is clockwise, and the winding direction of the other two sub-coils is counterclockwise, and the four sub-coils are connected in a "forward-reverse-forward-reverse" manner.

[0053] like Figure 1 , Figure 2 and Figure 3As shown, the transmitting coil 1 uses a square coil, the inner receiving coil 5 uses a square coil, and the outer receiving coil 6 is composed of four isosceles trapezoidal coils of the same size connected in series; two of the four isosceles trapezoidal coils are wound in a clockwise direction, and the other two are wound in a counterclockwise direction, and the four isosceles trapezoidal coils are connected in a "forward-reverse-forward-reverse" manner. The spatial structure of the receiving coil 3 is that the square inner receiving coil is in the middle, and the outer four sides of the square inner receiving coil are surrounded by the outer receiving coil composed of four isosceles trapezoidal coils; the outer receiving coil can achieve magnetic flux cancellation due to its winding method and spatial position, thereby realizing the mutual decoupling of the inner and outer receiving coils.

[0054] Fig.11 (a)- Fig.11 (e) is a partial schematic diagram of the receiving coil 3. In the figure, the inner receiving coil 5 is circular or square, and the outer receiving coil 6 is quadrilateral, arched, etc. The inner receiving coil placement area is closed or semi-closed. The receiving coil 3 can be further centrally symmetrical and rotationally symmetrical on the basis of the axially symmetrical structure, and the anti-deviation effect will be better.

[0055] The transmitting end further includes a primary magnetic core 2, and the receiving end further includes a secondary magnetic core 4. The primary magnetic core 2 is located on the surface of the transmitting coil 1 away from the receiving coil 3, and the secondary magnetic core 4 is located on the surface of the receiving coil 3 away from the transmitting coil 1. When the transmitting end is located above the receiving end, the primary magnetic core 2 is located on the upper surface of the transmitting coil 1, and the secondary magnetic core 4 is located on the lower surface of the receiving coil 3.

[0056] On the one hand, the present invention proposes a design method of a magnetic coupling structure with anti-offset characteristics, such as Figure 4 and Figure 5 As shown, the design method includes the following steps:

[0057] S1: Determine the external length L1, external width W1, external length L2 and external width W2 according to the actual application scenario, set constraints to simplify the complexity of the magnetic coupling structure: L1=W1=L2=W2=300mm; and determine the air gap distance H between the transmitter and the receiver according to the determined magnetic coupling structure, H=70mm.

[0058] S2: Set the number of turns of the transmitting coil N T , receiving the number of turns of the outer coil N out , receiving inner coil length L3, receiving inner coil width W3, receiving inner coil turns N in The upper and lower limits and initial value of L3=W3; specifically, the lower limit is used as the corresponding initial value.

[0059] S3: Determine the mutual inductance M between the transmitting coil 1 and the external receiving coil 6 through simulation TR1And the mutual inductance M between the transmitting coil 1 and the internal receiving coil 5 TR2 , according to the mutual inductance M between the transmitting coil 1 and the external receiving coil 6 TR1 and the mutual inductance M between the transmitting coil 1 and the internal receiving coil 5 TR2 Determine the total mutual inductance M TR ;

[0060] S4: Simulate the mutual inductance fluctuation ΔM under offset state through simulation TR , thereby generating a set of design parameters;

[0061] S4 is specifically:

[0062] The total mutual inductance M within the offset range is simulated by simulation TR And calculate the mutual inductance fluctuation ΔM TR , determine the mutual inductance fluctuation ΔM TR Whether it exceeds the first preset threshold, if it exceeds, it is a large range fluctuation, and it is necessary to increase the receiving inner coil length L3 and the receiving inner coil width W3. If it does not exceed, continue to judge the mutual inductance fluctuation ΔM TR Whether it exceeds the second preset threshold, if it exceeds, it is a medium range fluctuation, and the number of turns N of the receiving inner coil needs to be in Take the increase adjustment, if it does not exceed, continue to judge the mutual inductance fluctuation ΔM TR Whether it exceeds the third preset threshold, if it exceeds, it is a small range fluctuation, and the number of turns N of the receiving outer coil needs to be adjusted. out and the number of turns of the transmitting coil N T Take increasing adjustment until the mutual inductance fluctuation ΔM TR If it is lower than the third preset threshold, it is a high-quality design, and the current number of turns of the transmitting coil N is recorded. T , receiving the number of turns of the outer coil N out , receiving inner coil length L3, receiving inner coil width W3, receiving inner coil turns N in And as a set of design parameters. Among them, the first preset threshold> the second preset threshold> the third preset threshold. In this embodiment, the first preset threshold-the third preset threshold are 15%, 10%, and 5% respectively.

[0063] S5: Re-adjust the number of turns N of the transmitting coil T , receiving the number of turns of the outer coil N out , receiving inner coil length L3, receiving inner coil width W3, receiving inner coil turns N in , repeat S3 and S4 to obtain multiple sets of design parameters;

[0064] S6: Select the mutual inductance fluctuation ΔM TR The lowest design parameters and calculate the corresponding inductance L of the transmitting coil T , the inductance of the external receiving coil L R1 and the inductance L of the inner receiving coilR2 , completing the design of the magnetic coupling structure.

[0065] In this embodiment, N T =20, N in =8, N out =10, L3=133mm, W3=133mm, the inductance of the conventional square planar transmitting coil is L T =293.5μH, inductance of external receiving coil L R1 =25.1μH and the inductance of the inner receiving coil L R2 =130.7μH.

[0066] On the one hand, the present invention proposes a wireless power transmission system composed of a magnetic coupling structure with anti-offset characteristics, the wireless power transmission system includes a transmitting end and a receiving end; the transmitting end includes a DC voltage source, an inverter circuit and a primary resonant circuit, the primary resonant circuit includes a connected transmitting coil 1 and a primary compensation network LCC type compensation network, the receiving end includes a secondary internal resonant circuit, a secondary external resonant circuit, a secondary internal full-bridge rectifier filter circuit, a secondary external full-bridge rectifier filter circuit and a resistive load, the secondary internal resonant circuit includes a connected internal receiving coil 5 and a first secondary compensation network, the secondary external resonant circuit includes a connected external receiving coil 6 and a second secondary compensation network; the secondary internal full-bridge rectifier filter circuit and the secondary external full-bridge rectifier filter circuit are connected in series to form a complete secondary rectifier filter circuit.

[0067] According to the actual situation, the resistive load value R L With the output voltage V R It is required to determine the value of the DC voltage source V IN , the value of the DC voltage source V IN The formula is as follows:

[0068]

[0069] Among them, U IN It is the voltage after the DC voltage source is inverted.

[0070] The voltage U after the DC voltage source is inverted IN The formula is as follows:

[0071]

[0072] Among them, M TR is the total mutual inductance of the transmitting coil and the receiving coil, ω is the resonant angular frequency of the wireless power transmission system working in a resonant state, R TC is the compensation inductance L TC The resistance value, R T is the equivalent resistance of the primary receiving coil, R Ris the equivalent resistance of the secondary receiving coil, R E is the resistive load R L The equivalent resistance, U R is the equivalent resistance R E Fundamental voltage on R R1 is the resistance value of the secondary external receiving coil winding, R R2 is the resistance value of the receiving coil winding in the secondary side, V R is the output voltage.

[0073] The primary resonant circuit adopts LCC compensation topology, and the secondary inner resonant circuit and the secondary outer resonant circuit both adopt S-type compensation topology. The compensation inductor L is set according to the actual situation. TC And according to the resonance relationship, the compensation capacitor C of the LCC compensation topology in the primary resonant circuit is determined T1 , compensation capacitor C T2 ; Determine the compensation capacitor C of the S-type compensation topology of the secondary side external resonant circuit based on the resonance relationship R1 ; Determine the compensation capacitor C of the S-type compensation topology of the internal resonant circuit of the secondary side according to the resonance relationship R2 .

[0074] like Fig. 9 and Fig.10 As shown, the transmitting coil 1 and the LCC compensation topology form a primary resonant circuit, the inner receiving coil winding and the S-type compensation topology form a secondary internal resonant circuit, and the outer receiving coil winding and the S-type compensation topology form a secondary external resonant circuit. Set the compensation inductance L according to the actual situation. TC =35μH, compensation capacitor C of LCC compensation topology in primary resonant circuit T1 , compensation capacitor C T2 , Compensation capacitor C of the S-type compensation topology of the secondary side external resonant circuit R1 , the compensation capacitor C of the S-type compensation topology of the internal resonant circuit on the secondary side R2 It is determined according to the following relationship:

[0075]

[0076] Wherein, ω is the resonant angular frequency of the wireless power transmission system operating in a resonant state, satisfying ω=2πf, and f is the resonant frequency of the wireless power transmission system operating in a resonant state.

[0077] Figure 6 The circuit topology diagram of the wireless power transmission system composed of a magnetic coupling structure is shown. Figure 7 The figure shows the equivalent circuit diagram of the wireless power transmission system composed of magnetic coupling structure. TC is the compensation inductance L TC The resistance value, R Tis the equivalent resistance of the primary receiving coil, R R is the equivalent resistance of the secondary receiving coil, R E is the resistive load R L The equivalent resistance, U R is the equivalent resistance R E Fundamental voltage on L R is the equivalent inductance of the secondary receiving coil, C R is the equivalent capacitance of the secondary receiving coil, M TR is the equivalent mutual inductance, the equivalent resistance of the secondary receiving coil R R , R E , fundamental voltage U on equivalent resistance R , the equivalent inductance of the secondary receiving coil L R , the equivalent capacitance C of the secondary receiving coil R and equivalent mutual inductance M TR The specific expression is:

[0078]

[0079] Among them, R R1 is the resistance value of the secondary external receiving coil winding, R R2 is the resistance value of the receiving coil winding in the secondary side, R L is the resistive load value, V R is the output voltage, M R1 is the mutual inductance between the transmitting coil and the external receiving coil winding, M R1 is the mutual inductance between the transmitting coil and the inner receiving coil winding.

[0080] According to Kirchhoff's voltage law (KVL), the output voltage U is solved R , output power P out , as shown below:

[0081]

[0082] It can be seen that maintaining M TR The stability of the output voltage and output power can be guaranteed, that is, the anti-bias characteristic of the system can be realized.

[0083] Figure 8 What is shown is a curve diagram of the mutual inductance change of the X / Y direction offset of the wireless power transmission system. It can be seen that by adopting the magnetic coupling structure in the embodiment of the present invention, the deviation tolerance of the position misalignment within the offset range of -200 to +200 mm in the X / Y directions can be achieved, thereby improving the voltage output stability performance of the wireless power transmission system and further improving the system stability.

[0084] The present invention is not limited to this embodiment only, and any equivalent concepts or modifications and simplifications within the technical scope mentioned in the present invention are included in the protection scope of the present invention.

Claims

1. A magnetic coupling structure with anti-drift characteristics, comprising a transmitting end and a receiving end, characterized in that: The transmitting end comprises a transmitting coil (1); the receiving end comprises a receiving coil (3), the receiving coil (3) comprises an inner receiving coil (5) and an outer receiving coil (6), the inner receiving coil (5) is arranged inside the outer receiving coil (6), and the transmitting coil (1) is coupled with the inner receiving coil (5) and the outer receiving coil (6).

2. A magnetic coupling structure with anti-deviating characteristics according to claim 1, characterized in that: The receiving coil (3) is an axisymmetric structure; the outer receiving coil (6) is composed of four sub-coils of the same size connected in series in sequence; the four sub-coils are arranged along a circumference and the four sub-coils surround an inner receiving coil placement area, and the inner receiving coil (5) is arranged in the inner receiving coil placement area.

3. The magnetic coupling structure with anti-deviating characteristics according to claim 2, characterized in that: Among the four sub-coils, two sub-coils are wound in a clockwise direction, and the other two sub-coils are wound in a counterclockwise direction. The four sub-coils are connected in a "clockwise-counterclockwise-counterclockwise" manner.

4. The magnetic coupling structure with anti-deviating characteristics according to claim 2, characterized in that: The inner receiving coil (5) is circular or square.

5. The magnetic coupling structure with anti-deviating characteristics according to claim 1, characterized in that: The transmitting end further comprises a primary magnetic core (2), and the receiving end further comprises a secondary magnetic core (4), the primary magnetic core (2) being located on a surface of the transmitting coil (1) on a side away from the receiving coil (3), and the secondary magnetic core (4) being located on a surface of the receiving coil (3) on a side away from the transmitting coil (1).

6. A method for designing a magnetic coupling structure with anti-offset characteristics according to any one of claims 1 to 5, characterized in that: The design methodology includes the following steps: S1: Determine the external length L1, external width W1, external length L2 and external width W2 according to the actual application scenario; and determine the air gap distance H between the transmitting end and the receiving end; S2: Set the number of turns of the transmitting coil N T , receiving the number of turns of the outer coil N out , receiving inner coil length L3, receiving inner coil width W3, receiving inner coil turns N in The upper and lower limits and initial value of S3: Determine the mutual inductance M between the transmitting coil (1) and the external receiving coil (6) through simulation TR1 and the mutual inductance M between the transmitting coil (1) and the internal receiving coil (5) TR2 , according to the mutual inductance M between the transmitting coil (1) and the external receiving coil (6) TR1 and the mutual inductance M between the transmitting coil (1) and the internal receiving coil (5) TR2 Determine the total mutual inductance M TR ; S4: Simulate the mutual inductance fluctuation ΔM under offset state through simulation TR , thereby generating a set of design parameters; S5: Re-adjust the number of turns N of the transmitting coil T , receiving the number of turns of the outer coil N out , receiving inner coil length L3, receiving inner coil width W3, receiving inner coil turns N in , repeat S3 and S4 to obtain multiple sets of design parameters; S6: Select the mutual inductance fluctuation ΔM TR The lowest design parameters and calculate the corresponding inductance L of the transmitting coil T , the inductance of the external receiving coil L R1 and the inductance L of the inner receiving coil R2 , completing the design of the magnetic coupling structure.

7. The method for designing a magnetic coupling structure with anti-offset characteristics according to claim 6, characterized in that: The S4 is specifically: The total mutual inductance M within the offset range is simulated by simulation TR And calculate the mutual inductance fluctuation ΔM TR , determine the mutual inductance fluctuation ΔM TR Whether it exceeds the first preset threshold, if it exceeds, the receiving inner coil length L3 and the receiving inner coil width W3 are increased and adjusted, if it does not exceed, the mutual inductance fluctuation ΔM is continued to be determined TR Whether it exceeds the second preset threshold, if it exceeds, the number of turns N of the receiving inner coil is in Take the increase adjustment, if it does not exceed, continue to judge the mutual inductance fluctuation ΔM TR Whether it exceeds the third preset threshold, if it exceeds, the number of turns N of the receiving outer coil is out and the number of turns of the transmitting coil N T Take increasing adjustment until the mutual inductance fluctuation ΔM TR If it is lower than the third preset threshold, the current number of turns of the transmitting coil N is recorded. T , receiving the number of turns of the outer coil N out , receiving inner coil length L3, receiving inner coil width W3, receiving inner coil turns N in and as a set of design parameters.

8. A wireless power transmission system composed of the magnetic coupling structure with anti-deviating characteristics as claimed in any one of claims 1 to 5, characterized in that: The wireless power transmission system comprises the transmitting end and the receiving end; the transmitting end comprises a DC voltage source, an inverter circuit and a primary resonance circuit, the primary resonance circuit comprises a connected transmitting coil (1) and a primary compensation network, the receiving end comprises a secondary internal resonance circuit, the secondary external resonance circuit, a secondary internal full-bridge rectifier filter circuit, a secondary external full-bridge rectifier filter circuit and a resistive load, the secondary internal resonance circuit comprises a connected internal receiving coil (5) and a first secondary compensation network, the secondary external resonance circuit comprises a connected external receiving coil (6) and a second secondary compensation network; the secondary internal full-bridge rectifier filter circuit and the secondary external full-bridge rectifier filter circuit are connected in series to form a complete secondary rectifier filter circuit.

9. A wireless power transmission system composed of a magnetic coupling structure with anti-deviating characteristics according to claim 8, characterized in that: The value of the DC voltage source V IN The formula is as follows: Among them, U IN is the voltage after the DC voltage source is inverted; The voltage U after the DC voltage source is inverted IN The formula is as follows: Among them, M TR is the total mutual inductance of the transmitting coil and the receiving coil, ω is the resonant angular frequency of the wireless power transmission system working in a resonant state, R TC is the compensation inductance L TC The resistance value, R T is the equivalent resistance of the primary receiving coil, R R is the equivalent resistance of the secondary receiving coil, R E is the resistive load R L The equivalent resistance, U R is the equivalent resistance R E Fundamental voltage on R R1 is the resistance value of the secondary outer receiving coil winding, R R2 is the resistance value of the receiving coil winding in the secondary side, V R is the output voltage.

10. A wireless power transmission system composed of a magnetic coupling structure with anti-deviating characteristics according to claim 8, characterized in that: The primary compensation network adopts an LCC compensation topology, and the first secondary compensation network and the second secondary compensation network both adopt an S-type compensation topology.

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