Optimization design method of dual-band shielding ring of wireless power transmission system

Abstract

The present application belongs to the field of wireless power transmission and electromagnetic field, and particularly relates to a kind of optimization design method of double-band shielding ring of wireless power transmission system, the method is by mathematical modeling to double-band shielding ring, by model analysis to obtain voltage equation group, the analytical expression of equivalent permeability of double-band shielding ring is solved;At the same time, the relationship between the resonant frequency of double-band shielding ring and the resonant frequency of top layer and bottom layer element is quantitatively analyzed, which helps to optimize the structure parameters of double-band shielding ring and realize the magnetic field shaping of specific frequency band of wireless power transmission system.

Description

Technical Field

[0001] This invention belongs to the field of wireless power transmission and electromagnetic field technology, and specifically relates to an optimized design method for a dual-band shielding ring in a wireless power transmission system. Background Technology

[0002] Weaponry and equipment are showing a trend towards networking, intelligence, and unmanned operation. Unmanned vehicles and drone swarms, among other unmanned equipment, need to possess long-term cruising and flexible maneuverability capabilities for tasks such as forward reconnaissance, situational awareness, and target raids. These unmanned systems are characterized by fully electric drive, but due to limitations in battery capacity and wired power supply methods, they face difficulties in ensuring reliable power supply during long-duration missions, which compromises the equipment's stealth and reduces the mechanical lifespan of connectors.

[0003] Wireless power transfer technology enables the remote transmission of energy from the power source to the energy storage device of unmanned military equipment, pioneering a new mode of energy transfer from fixed power sources. It offers the following advantages: 1) achieving "unmanned autonomous" power supply for equipment; 2) ensuring "highly efficient and reliable" energy supply; and 3) enabling "flexible and secure" energy transmission. Introducing information transmission into wireless power transfer technology allows for "precise" information exchange between equipment, enabling monitoring of system operating status and ensuring communication quality and safe operation between equipment.

[0004] However, due to the influence of spatial electromagnetic distribution factors, current wireless power transmission systems are prone to electromagnetic field leakage during operation, causing vehicle body deformation, reducing the protection and safety performance of the equipment; and interfering with various sensor devices in unmanned equipment, threatening the normal operation of the system, thus making it impossible to accurately grasp the target status.

[0005] Dual-band shielding rings, by adjusting their key physical dimensions and varying array combinations, achieve desired electromagnetic parameters, thereby reducing magnetic field leakage in specific frequency bands and minimizing electromagnetic interference to surrounding equipment. Therefore, applying them to wireless power transmission systems can significantly improve the system's electromagnetic compatibility. However, most existing shielding ring design methods extract their "macroscopic" constitutive parameters through equivalent medium theory, requiring analysis and design based on electromagnetic wave theory. This approach relies on parameter scanning and manual selection of unit structure dimensions, resulting in complex modeling and significant time consumption. Furthermore, circuit numerical calculation is another optimization path, requiring numerical analysis in conjunction with the wireless power transmission system, and cannot fundamentally optimize the shielding ring design. In addition, research on shielding ring characteristics mainly focuses on single frequencies, lacking optimization design for dual-band shielding rings.

[0006] Therefore, establishing an optimized model for dual-band shielding rings and evaluating their electromagnetic characteristics is a pressing issue. Optimized design of dual-band shielding rings holds promise for achieving precise control of the spatial magnetic field in wireless power transmission systems. Summary of the Invention

[0007] (I) Technical Issues

[0008] The technical problem this invention aims to solve is: addressing the issue that existing methods cannot guide the design of dual-band shielding rings, how to provide an optimized design method for dual-band shielding rings in wireless power transmission systems, forming a set of design guidelines for dual-band shielding ring structures, and achieving active shaping of the high-frequency leakage magnetic field in wireless power transmission systems.

[0009] (II) Technical Solution

[0010] To address the aforementioned technical problems, this invention provides an optimized design method for a dual-band shielding ring in a wireless power transmission system, the method comprising the following steps:

[0011] Step 1: The dual-band shielding ring is equivalent to the top layer element, the bottom layer element, and the RLC resonant circuit of the PCB substrate / PMMA substrate; wherein, the top layer element includes the top layer metal spiral coil and the top layer series compensation capacitor, and the bottom layer element includes the bottom layer metal spiral coil and the bottom layer series compensation capacitor.

[0012] Among them, based on the resistance R of the top metal spiral coil and the bottom metal spiral coil l and R h Inductor L l and L h Series compensation capacitor C l and C h And the coupling mutual inductance M between the top metal spiral coil and the bottom metal spiral coil. lh A mathematical model of a dual-band magnetic field shielding ring was established.

[0013] Step 2: An external time-harmonic magnetic field is applied to induce current in the top and bottom elements of all dual-band shielding rings. and Among them, a certain dual-band shielding ring is simultaneously subjected to the combined effects of the total electromotive force generated by the external excitation magnetic field, the total electromotive force generated by the induced magnetic field of other surrounding elements, and the total electromotive force generated by the induced magnetic field between the top element and the bottom element, and the voltage equations of the top element and the bottom element are derived respectively.

[0014] Step 3: Based on the voltage equation derived in Step 2, solve for the induced current of the top-level element. and the induced current of the underlying basic unit Further calculation of the equivalent magnetization vector of the dual-band shielding ring.

[0015] Step 4: Solve for the equivalent magnetic susceptibility χ of the dual-band shielding ring. m The equivalent relative complex permeability μ of the dual-band shielding ring was obtained through numerical solution. r ;

[0016] Step 5: The equivalent relative complex permeability of the dual-band shielding ring is related to its frequency. The first frequency ω1 of the dual-band shielding ring is adjusted by the top-layer metal spiral coil and the top-layer series compensation capacitor. The second frequency ω2 of the dual-band shielding ring needs to consider the coupling mutual inductance M between the top and bottom metal spiral coils. lh It is regulated by the bottom metal spiral coil and the bottom series compensation capacitor.

[0017] In step 2, the magnetic induction intensity of the applied time-harmonic magnetic field Where μ0 is the free permeability. The magnetic field strength is the applied time-harmonic magnetic field.

[0018] In step 2, the voltage equations for the top-level and bottom-level primitives are derived as follows:

[0019]

[0020] Where j is the imaginary unit, ω is the system angular frequency, m and n are the total number of turns of the top and bottom metal spiral coils, respectively, and S k Let be the area enclosed by the k-th turn of the metal spiral. Let be the magnetic flux density of the external magnetic field excitation passing through the k-th loop. For the top-level primitive and the surrounding p l -1 The sum of the magnetic flux density vectors generated by the induced currents of the top-layer elementary elements, passing through the k-th loop of the top-layer metal spiral. For p h The sum of the magnetic induction vectors of the kth turn of the metal spiral of the bottom and top primitives. For the underlying primitives and surrounding p h -1 The magnetic flux density vector generated by the induced current of the bottom element passing through the kth turn of the top metal spiral, For p l The sum of the magnetic induction vectors of the top and bottom metal spirals of each primitive element on the kth turn.

[0021] In step 2, the magnetic induction intensity vectors correspond to the mutual inductance between the top / bottom element and other surrounding top / bottom elements, and the mutual inductance between the top and bottom elements, respectively. Therefore, the voltage equation is transformed into:

[0022]

[0023]

[0024] Among them, L efflc L is the equivalent inductance of all the top-layer metal spiral coils. effhc L is the equivalent inductance of all the underlying metal spiral coils. efflo L is the equivalent inductance of all the top-layer metal spiral coils and the bottom-layer metal spiral coils. effho This represents the equivalent inductance of all bottom-layer metal spiral coils and the top-layer metal spiral coil.

[0025] In step 3, the induced current of the top-level element is obtained by solving the voltage equation. and the induced current of the underlying basic unit The equivalent magnetization vector of the dual-band shielding ring is further obtained. The calculation formula is:

[0026]

[0027] Among them, V unit For the volume of the dual-band shielding ring, e m It is a unit vector.

[0028] In step 4, the equivalent magnetization vector is used as a basis for... magnetic field strength relative to the applied time harmonic magnetic field The ratio of the two frequencies is used to obtain the equivalent magnetic susceptibility χ of the dual-band shielding ring. m .

[0029] In step 4, the equivalent magnetic susceptibility χ of the dual-band shielding ring is used. m Furthermore, the equivalent complex relative permeability μ of the dual-band shielding ring r for:

[0030]

[0031] in, The coupling coefficient is... The quality factor of the top metal spiral coil. ω is the quality factor of the bottom metal spiral coil. l ω is the resonant frequency of the top element. h S is the resonant frequency of the underlying element. l S is the total area enclosed by the top layer of metal spiral coils. h The total area enclosed by the bottom metal spiral coil.

[0032] The relationship between the resonant frequency of the dual-band shielding ring and the resonant frequencies of the top and bottom layer elements is as follows:

[0033]

[0034] When the resonant frequency of the top-level element is much lower than that of the bottom-level element, ω can be obtained. l =ω1, By adjusting the resonant frequencies of the top and bottom layers, the equivalent permeability resonant frequency of the dual-band shielding ring can be precisely controlled.

[0035] The method belongs to the field of wireless power transmission and electromagnetic field technology, and forms a set of design guidelines for dual-band shielding ring structures to achieve active shaping of the high-frequency leakage magnetic field of wireless power transmission systems.

[0036] (III) Technical Effects

[0037] Compared with the prior art, the above technical solution conceived by this invention can achieve the following beneficial effects:

[0038] (1) The optimization design method of the dual-band shielding ring of the wireless power transmission system provided by the present invention establishes an equivalent circuit model of the dual-band shielding ring, considers the mutual coupling between each element, obtains the relationship between the constitutive parameters of the dual-band shielding ring and the operating frequency, establishes a unit structure optimization design paradigm, and can intuitively show the intrinsic connection between the electromagnetic response of the element and the overall macroscopic electromagnetic response of the dual-band shielding ring.

[0039] (2) The optimization design method of the dual-band shielding ring of the wireless power transmission system provided by the present invention optimizes the structural parameters of the dual-band shielding ring by constitutive parameter characterization. The dual-band shielding ring unit structure can be optimized according to the magnetic field leakage frequency of the wireless power transmission system, thereby avoiding complicated simulation modeling. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the external excitation magnetic field incident on the dual-band shielding ring of the present invention;

[0041] Figure 2 The equivalent circuit model diagram of the dual-band shielding ring provided in the embodiment of the present invention is shown below;

[0042] Figure 3 This is a flowchart of the optimized design method for the dual-band shielding ring of the present invention;

[0043] Figure 4 Constitutive parameter curves of a dual-band shielding ring provided in an embodiment of the present invention;

[0044] Figures 5(a) and 5(b) are schematic diagrams of the magnetic field strength of the dual-band shielding ring of the wireless power transmission system provided in the embodiments of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the specific embodiments of this invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0046] Since the wavelength of electromagnetic waves is much larger than the size of the dual-band shielding ring, the metamaterial can be considered as an infinitely large plane, meaning the current within each unit is essentially the same. Therefore, the non-uniformity of the electromagnetic response of the elementary elements in the vicinity of the element can be ignored, and the dual-band shielding ring composed of a large number of microscopic elements can be described by equivalent permeability. Assuming a uniform external time-harmonic excitation magnetic field is incident perpendicularly to the dual-band spiral structure unit, this external magnetic field induces current in all elements within the dual-band shielding ring, as shown in the schematic diagram below. Figure 1 As shown. Since the resonant frequency of the element is closely related to the structure of the element itself, in order to make the shielding ring have two operating frequencies, a top layer and a bottom layer spiral pattern will be used, and the patterns of the two layers will be different. The element frequency will be adjusted by adding an external compensation capacitor.

[0047] To address the aforementioned technical problems, this invention provides an optimized design method for a dual-band shielding ring in a wireless power transmission system, the method comprising the following steps:

[0048] Step 1: The dual-band shielding ring is equivalent to the top layer element, the bottom layer element, and the RLC resonant circuit of the PCB substrate / PMMA substrate; wherein, the top layer element includes the top layer metal spiral coil and the top layer series compensation capacitor, and the bottom layer element includes the bottom layer metal spiral coil and the bottom layer series compensation capacitor.

[0049] Among them, based on the resistance R of the top metal spiral coil and the bottom metal spiral coil l and R h Inductor L l and L h Series compensation capacitor C l and C h And the coupling mutual inductance M between the top metal spiral coil and the bottom metal spiral coil. lh A mathematical model of a dual-band magnetic field shielding ring was established.

[0050] Step 2: An external time-harmonic magnetic field is applied to induce current in the top and bottom elements of all dual-band shielding rings. and Among them, a certain dual-band shielding ring is simultaneously subjected to the combined effects of the total electromotive force generated by the external excitation magnetic field, the total electromotive force generated by the induced magnetic field of other surrounding elements, and the total electromotive force generated by the induced magnetic field between the top element and the bottom element, and the voltage equations of the top element and the bottom element are derived respectively.

[0051] Step 3: Based on the voltage equation derived in Step 2, solve for the induced current of the top-level element. and the induced current of the underlying basic unit Further calculation of the equivalent magnetization vector of the dual-band shielding ring.

[0052] Step 4: Solve for the equivalent magnetic susceptibility χ of the dual-band shielding ring. m The equivalent relative complex permeability μ of the dual-band shielding ring was obtained through numerical solution. r ;

[0053] Step 5: The equivalent relative complex permeability of the dual-band shielding ring is related to its frequency. The first frequency ω1 of the dual-band shielding ring is adjusted by the top-layer metal spiral coil and the top-layer series compensation capacitor. The second frequency ω2 of the dual-band shielding ring needs to consider the coupling mutual inductance M between the top and bottom metal spiral coils. lh It is regulated by the bottom metal spiral coil and the bottom series compensation capacitor.

[0054] In step 2, the magnetic induction intensity of the applied time-harmonic magnetic field Where μ0 is the free permeability. The magnetic field strength is the applied time-harmonic magnetic field.

[0055] In step 2, the voltage equations for the top-level and bottom-level primitives are derived as follows:

[0056]

[0057] Where j is the imaginary unit, ω is the system angular frequency, m and n are the total number of turns of the top and bottom metal spiral coils, respectively, and S k Let be the area enclosed by the k-th turn of the metal spiral. Let be the magnetic flux density of the external magnetic field excitation passing through the k-th loop. For the top-level primitive and the surrounding p l -1 The sum of the magnetic flux density vectors generated by the induced currents of the top-layer elementary elements, passing through the k-th loop of the top-layer metal spiral. For p h The sum of the magnetic induction vectors of the kth turn of the metal spiral of the bottom and top primitives. For the underlying primitives and surrounding p h -1 The magnetic flux density vector generated by the induced current of the bottom element passing through the kth turn of the top metal spiral, For p l The sum of the magnetic induction vectors of the top and bottom metal spirals of each primitive element on the kth turn.

[0058] In step 2, the magnetic induction intensity vectors correspond to the mutual inductance between the top / bottom element and other surrounding top / bottom elements, and the mutual inductance between the top and bottom elements, respectively. Therefore, the voltage equation is transformed into:

[0059]

[0060]

[0061] Among them, L efflc L is the equivalent inductance of all the top-layer metal spiral coils. effhc L is the equivalent inductance of all the underlying metal spiral coils. efflo L is the equivalent inductance of all the top-layer metal spiral coils and the bottom-layer metal spiral coils. effho This represents the equivalent inductance of all bottom-layer metal spiral coils and the top-layer metal spiral coil.

[0062] In step 3, the induced current of the top-level element is obtained by solving the voltage equation. and the induced current of the underlying basic unit The equivalent magnetization vector of the dual-band shielding ring is further obtained. The calculation formula is:

[0063]

[0064] Among them, V unit For the volume of the dual-band shielding ring, e m It is a unit vector.

[0065] In step 4, the equivalent magnetization vector is used as a basis for... magnetic field strength relative to the applied time harmonic magnetic field The ratio of the two frequencies is used to obtain the equivalent magnetic susceptibility χ of the dual-band shielding ring. m .

[0066] In step 4, the equivalent magnetic susceptibility χ of the dual-band shielding ring is used. m Furthermore, the equivalent complex relative permeability μ of the dual-band shielding ring r for:

[0067]

[0068] in, The coupling coefficient is... The quality factor of the top metal spiral coil. ω is the quality factor of the bottom metal spiral coil. l ω is the resonant frequency of the top element. h S is the resonant frequency of the underlying element. lS is the total area enclosed by the top layer of metal spiral coils. h The total area enclosed by the bottom metal spiral coil.

[0069] The relationship between the resonant frequency of the dual-band shielding ring and the resonant frequencies of the top and bottom layer elements is as follows:

[0070]

[0071] When the resonant frequency of the top-level element is much lower than that of the bottom-level element, ω can be obtained. l =ω1, By adjusting the resonant frequencies of the top and bottom layers, the equivalent permeability resonant frequency of the dual-band shielding ring can be precisely controlled.

[0072] The method belongs to the field of wireless power transmission and electromagnetic field technology, and forms a set of design guidelines for dual-band shielding ring structures to achieve active shaping of the high-frequency leakage magnetic field of wireless power transmission systems.

[0073] Example 1

[0074] The present invention provides an optimized design method for a dual-band shielding ring in a wireless power transmission system, comprising the following steps:

[0075] (1) The dual-band shielding ring is equivalent to an RLC resonant circuit consisting of a top-layer element, a bottom-layer element, and a PCB / PMMA substrate, such as Figure 2 As shown. The resistance R of the top and bottom metal spiral coils is... l and R h Inductor L l and L h Series compensation capacitor C l and C h Mutual inductance M between the metal spiral coil and the coupling lh A mathematical model of a dual-band magnetic field shielding ring is established.

[0076] (2) The external time-harmonic excitation magnetic field incident on the dual-band shielding ring is: This magnetic field induces currents in the top and bottom metal spirals of all the elements in the dual-band shielding ring. and For a given dual-band shielding ring element, the combined effects of the total electromotive force generated by the applied excitation magnetic field, the total electromotive force generated by the induced magnetic fields of other surrounding top or bottom element elements, and the total electromotive force generated by the induced magnetic fields between the top and bottom element elements correspond to the following: Figure 2 The electromotive forces e1, e2(e 2_l / e 2_h ), e3(e 3-l / e 3-hFurther derivation yields the voltage equations for the top-layer and bottom-layer spiral structures:

[0077]

[0078] Where m and n are the total number of turns of the top and bottom metal spirals, respectively, and S k Let be the area enclosed by the k-th turn of the metal spiral. Let be the magnetic flux density of the external magnetic field excitation passing through the k-th loop. For the top-level primitive and the surrounding p l -1 The sum of the magnetic flux density vectors generated by the induced currents of the top-layer elementary elements, passing through the k-th loop of the top-layer metal spiral. For p h The sum of the magnetic induction vectors of the kth turn of the metal spiral of the bottom and top primitives. The underlying layer is based on the surrounding p h -1 The magnetic flux density vector generated by the induced current of the bottom element passing through the kth turn of the top metal spiral, For p l The sum of the magnetic induction vectors of the top and bottom metal spirals of each primitive element on the kth turn.

[0079] The above magnetic field strength vectors correspond to the mutual inductance between the top-layer / bottom-layer element and other surrounding top-layer / bottom-layer elements, respectively. The mutual inductance between the top-layer and bottom-layer elements is expressed by the voltage equation as follows:

[0080]

[0081]

[0082] Among them, L efflc For the equivalent inductance of all top-level primitives, L effhc L is the equivalent inductance of all underlying primitives. efflo L is the equivalent inductance of all top-level and bottom-level primitives. effho This is the equivalent inductance of all bottom-level primitives and top-level primitives.

[0083] (3) The induced current of the top spiral structure is calculated based on the listed voltage equations. Induced current in the underlying spiral structure Summing the magnetic dipole moments generated by each turn of the metal spiral, in the dual-band shielding ring volume V unit The average value is calculated internally, and then the equivalent magnetization vector of the dual-band shielding ring is further calculated.

[0084]

[0085] (4) Further solve for the equivalent magnetic susceptibility χ of the dual-band shielding ring.m The equivalent complex permeability expression μ of the dual-band shielding ring can be obtained. r for:

[0086]

[0087] in, The coupling coefficient is... The quality factor of the top metal spiral coil. ω is the quality factor of the bottom metal spiral coil. l ω is the resonant frequency of the top element. h S is the resonant frequency of the underlying element. l S is the total area enclosed by the top layer of metal spiral coils. h The total area enclosed by the bottom metal spiral coil.

[0088] (5) The equivalent permeability of the dual-band shielding ring is related to its frequency. Specifically, the first frequency ω1 of the dual-band shielding ring is adjusted by the top-layer metal spiral coil and the top-layer series compensation capacitor. The second frequency ω2 of the dual-band shielding ring needs to consider the mutual inductance coupling M between the top layer and the top-layer coil. lh The adjustment is achieved using a bottom-layer metal spiral coil and a bottom-layer series compensation capacitor. Based on the above formula, the relationship between the resonant frequency of the dual-band shielding ring and the resonant frequencies of the top and bottom layer elements is as follows:

[0089]

[0090]

[0091] When the resonant frequency of the top-level element is much lower than that of the bottom-level element, ω can be obtained. l =ω1, By adjusting the resonant frequencies of the top and bottom layers, the equivalent permeability resonant frequency of the dual-band shielding ring can be precisely controlled.

[0092] In summary, the optimized design process for a dual-band shielding ring in a wireless power transmission system is as follows: Figure 3 As shown.

[0093] Based on the above steps, a dual-band shielding ring was designed to reduce magnetic field leakage in wireless power transfer systems with resonant frequencies of 13.56MHz and 27.12MHz. In this embodiment of the invention, the physical parameters of the dual-band shielding ring are as follows:

[0094] The outer side length of the top-layer metal spiral coil structure is 13cm, with 4 turns, and the inner side length is 6cm. The outer side length of the bottom-layer metal spiral coil structure is 13cm, with 2 turns, and the inner side length is 10cm. The linewidth and turn spacing of the top and bottom metal spiral coils are 3mm and 2mm, respectively, and the thickness of the dielectric substrate is 1.6mm. A top-layer series compensation capacitor C is added at both ends of the top-layer metal spiral coil. l =74pF, with series compensation capacitors C added at both ends of the bottom metal spiral coil. h Impedance matching is performed with a permeability of 53pF. The equivalent permeability of the designed dual-band shielding ring is as follows: Figure 4 As shown, it exhibits a double-resonant configuration, where the real part of the effective permeability initially increases with frequency, then decreases sharply near the resonant frequency ω1, reaches a minimum, gradually increases, and returns to near zero. It then continues to increase with frequency, decreases sharply near the resonant frequency ω2, reaches a minimum, and gradually increases again, returning to near zero. The real part of the effective permeability of this dual-band shielding ring is close to zero at both 13.56MHz and 27.12MHz.

[0095] To verify the accuracy of the proposed dual-band shielding ring optimization design method, the dual-band shielding ring of this embodiment was inserted into the receiver side of the wireless power transmission system, and the system operating frequency was set to f. 01 =13.56MHz, f 02 =27.12MHz. Observation points along the system axis were selected, and the magnetic field strength was simulated at distances from the dual-band shielding ring ranging from 6cm to 20cm, with 2cm intervals. Compared to the original wireless power transmission system, the magnetic field strength significantly decreased after the dual-band shielding ring was introduced. The simulation results are shown in Figures 5(a) and 5(b). Figure 5(a) shows the magnetic field strength of the 13.56MHz system without and with the dual-band shielding ring, while Figure 5(b) shows the magnetic field strength of the 27.12MHz system without and with the dual-band shielding ring. Therefore, the method provided by this invention allows for more precise adjustment of the resonant frequency of the dual-band shielding ring, enabling magnetic field shaping of specific frequency bands in the wireless power transmission system.

[0096] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An optimized design method for a dual-band shielding ring in a wireless power transmission system, characterized in that, The method includes the following steps: Step 1: The dual-band shielding ring is equivalent to the top layer element, the bottom layer element, and the RLC resonant circuit of the PCB substrate / PMMA substrate; wherein, the top layer element includes the top layer metal spiral coil and the top layer series compensation capacitor, and the bottom layer element includes the bottom layer metal spiral coil and the bottom layer series compensation capacitor. Among them, based on the resistance R of the top metal spiral coil and the bottom metal spiral coil l and R h Inductor L l and L h Series compensation capacitor C l and C h And the coupling mutual inductance M between the top metal spiral coil and the bottom metal spiral coil. lh A mathematical model of a dual-band magnetic field shielding ring was established. Step 2: An external time-harmonic magnetic field is applied to induce current in the top and bottom elements of all dual-band shielding rings. and Among them, a certain dual-band shielding ring is simultaneously subjected to the combined effects of the total electromotive force generated by the external excitation magnetic field, the total electromotive force generated by the induced magnetic field of other surrounding elements, and the total electromotive force generated by the induced magnetic field between the top element and the bottom element, and the voltage equations of the top element and the bottom element are derived respectively. Step 3: Based on the voltage equation derived in Step 2, solve for the induced current of the top-level element. and the induced current of the underlying basic unit Further calculation of the equivalent magnetization vector of the dual-band shielding ring. Step 4: Solve for the equivalent magnetic susceptibility χ of the dual-band shielding ring. m The equivalent relative complex permeability μ of the dual-band shielding ring was obtained through numerical solution. r ; Step 5: The equivalent relative complex permeability of the dual-band shielding ring is related to its frequency. The first frequency ω1 of the dual-band shielding ring is adjusted by the top-layer metal spiral coil and the top-layer series compensation capacitor. The second frequency ω2 of the dual-band shielding ring needs to consider the coupling mutual inductance M between the top and bottom metal spiral coils. lh It is regulated by the bottom metal spiral coil and the bottom series compensation capacitor.

2. The optimized design method for a dual-band shielding ring in a wireless power transmission system as described in claim 1, characterized in that, In step 2, the magnetic induction intensity of the applied time-harmonic magnetic field Where μ0 is the free permeability. The magnetic field strength is the applied time-harmonic magnetic field.

3. The optimized design method for a dual-band shielding ring in a wireless power transmission system as described in claim 2, characterized in that, In step 2, the voltage equations for the top-level and bottom-level primitives are derived as follows: Where j is the imaginary unit, ω is the system angular frequency, m and n are the total number of turns of the top and bottom metal spiral coils, respectively, and S k Let be the area enclosed by the k-th turn of the metal spiral. Let be the magnetic flux density of the external magnetic field excitation passing through the k-th loop. For the top-level primitive and the surrounding p l -1 The sum of the magnetic flux density vectors generated by the induced currents of the top-layer elementary elements, passing through the k-th loop of the top-layer metal spiral. For p h The sum of the magnetic induction vectors of the kth turn of the metal spiral of the bottom and top primitives. For the underlying primitives and surrounding p h -1 The magnetic flux density vector generated by the induced current of the bottom element passing through the kth turn of the top metal spiral, For p l The sum of the magnetic induction vectors of the top and bottom metal spirals of each primitive element on the kth turn.

4. The optimized design method for a dual-band shielding ring in a wireless power transmission system as described in claim 3, characterized in that, In step 2, the magnetic induction intensity vectors correspond to the mutual inductance between the top / bottom element and other surrounding top / bottom elements, and the mutual inductance between the top and bottom elements, respectively. Therefore, the voltage equation is transformed into: Among them, L efflc L is the equivalent inductance of all the top-layer metal spiral coils. effhc L is the equivalent inductance of all the underlying metal spiral coils. efflo L is the equivalent inductance of all the top-layer metal spiral coils and the bottom-layer metal spiral coils. effho This represents the equivalent inductance of all bottom-layer metal spiral coils and the top-layer metal spiral coil.

5. The optimized design method for a dual-band shielding ring in a wireless power transmission system as described in claim 4, characterized in that, In step 3, the induced current of the top-level element is obtained by solving the voltage equation. and the induced current of the underlying basic unit The equivalent magnetization vector of the dual-band shielding ring is further obtained. The calculation formula is: Among them, V unit For the volume of the dual-band shielding ring, e m It is a unit vector.

6. The optimized design method for a dual-band shielding ring in a wireless power transmission system as described in claim 5, characterized in that, In step 4, based on the equivalent magnetization vector magnetic field strength relative to the applied time harmonic magnetic field The ratio of the two frequencies is used to obtain the equivalent magnetic susceptibility χ of the dual-band shielding ring. m .

7. The optimized design method for a dual-band shielding ring in a wireless power transmission system as described in claim 6, characterized in that, In step 4, based on the equivalent magnetic susceptibility χ of the dual-band shielding ring... m Furthermore, the equivalent complex relative permeability μ of the dual-band shielding ring r for: in, The coupling coefficient is... The quality factor of the top metal spiral coil. ω is the quality factor of the bottom metal spiral coil. l ω is the resonant frequency of the top element. h S is the resonant frequency of the underlying element. l S is the total area enclosed by the top layer of metal spiral coils. h The total area enclosed by the bottom metal spiral coil.

8. The optimized design method for a dual-band shielding ring in a wireless power transmission system as described in claim 7, characterized in that, The relationship between the resonant frequency of the dual-band shielding ring and the resonant frequencies of the top and bottom layer elements is as follows: 。 9. The optimized design method for a dual-band shielding ring in a wireless power transmission system as described in claim 8, characterized in that, When the resonant frequency of the top element is much lower than that of the bottom element, ω can be obtained. l =ω1, By adjusting the resonant frequencies of the top and bottom layers, the equivalent permeability resonant frequency of the dual-band shielding ring can be precisely controlled.

10. The optimized design method for a dual-band shielding ring in a wireless power transmission system as described in claim 1, characterized in that, The method belongs to the field of wireless power transmission and electromagnetic field technology, and forms a set of design guidelines for dual-band shielding ring structures, realizing the active shaping of high-frequency leakage magnetic fields in wireless power transmission systems.

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