CN-115765210-B - Design method of wireless power transmission system based on spiral resonant cavity

Abstract

The invention discloses a design method of a wireless power transmission system based on a spiral resonant cavity, which comprises a transmitting coil, a receiving coil, a medium substrate and the spiral resonant cavity arranged on the medium substrate, wherein the spiral resonant cavity comprises a plane square spiral coil, a plane round spiral coil, a split ring and a compensation capacitor, the plane square spiral coil, the plane round spiral coil and the split ring are sequentially distributed from the center of the medium substrate to the edge of the medium substrate, the medium substrate is positioned between the transmitting coil and the receiving coil, the positions of the medium substrate are adjusted according to the coupling degree of the medium substrate spiral resonant cavity, the transmitting coil and the receiving coil to change the transmission efficiency, after an alternating magnetic field in the transmitting coil is incident on the medium substrate, the originally divergent magnetic field changes direction to start gathering, and the receiving coil receives more energy, so that the transmission distance of wireless power transmission is increased, and the transmission efficiency of the system is improved.

Inventors

• WANG MENG
• WANG MENGMENG
• SHI YANYAN
• GUO JINGJING
• SUN YILONG

Assignees

• 河南师范大学

Dates

Publication Date

20260512

Application Date

20221127

Claims (5)

1. 1. A design method of a wireless power transmission system based on a spiral resonant cavity is characterized in that the wireless power transmission system comprises a transmitting coil, a receiving coil, a medium substrate and the spiral resonant cavity arranged on the medium substrate, wherein the transmitting coil, the medium substrate and the receiving coil are all planar circular spiral coils and are completely identical in structure, the transmitting coil, the medium substrate and the receiving coil are coaxially and oppositely arranged in sequence, the minimum inner diameter r 1 of the transmitting coil and the receiving coil is 30mm, the maximum outer diameter r 2 of the transmitting coil is 58mm, the turn distance is 1mm, the number of turns is 7, the spiral resonant cavity is printed on one side of the medium substrate, the spiral resonant cavity is formed by planar square spiral coils, planar circular spiral coils, opening rings and compensation capacitors, the planar square spiral coils, the planar circular spiral coils and the opening rings are sequentially arranged from the center of the medium substrate to the edge of the medium substrate, the line widths w of the planar square spiral coils and the planar circular spiral coils are 2mm, the line widths g of the opening rings are 2mm, the thicknesses of the planar square spiral coils, the planar square spiral coils and the opening rings are 0.1mm, the compensation capacitors are welded at the opening gaps, the optimal distance between the transmitting ring and the receiving ring is 5D, and the receiving ring is 0.5D, and the range of the wireless power transmission performance is 0/D, and the range between the wireless power transmission range is 5D and the range is 0/D and the range is satisfied.
2. 2. The method for designing a wireless power transmission system based on a spiral resonant cavity according to claim 1, wherein the dielectric substrate is square, the material of the dielectric substrate is FR 4 , the dielectric constant ε r =4.4, the thickness is 1.6mm, and the length and the width are 140mm.
3. 3. The method of claim 1, wherein the compensation capacitor is a high-frequency patch capacitor, and the compensation capacitor C p is 330pF.
4. 4. The method for designing the wireless power transmission system based on the spiral resonant cavity according to claim 1, wherein the optimal placement position of the medium substrate is determined by increasing the value of D from 2.5r 2 /100 to 4r 2 according to the step change amount of 1.5r 2 in the value range of [2.5r 2 , 4r 2 ], calculating the value of D corresponding to the highest transmission efficiency when D takes different values, solving the problem that when D is a set value in the value range, increasing the value of D from 0 to D according to the step change amount of D/100 in the change range of [0, D ], calculating the S parameter of the whole wireless power transmission system when D takes different values, calculating the transmission efficiency of the system by utilizing the S parameter, recording the values corresponding to D and D as D i and D i respectively when the efficiency is the maximum, finally obtaining 100 groups of data, namely D i and D i , i=1, 2, 3..100, fitting the obtained final groups of data according to the obtained data, and carrying out the final placement of the obtained groups of 100, and obtaining the optimal placement position of the medium substrate according to the obtained d=2.
5. 5. The method for designing a wireless power transmission system based on a spiral resonant cavity according to claim 1, wherein the specific design process of the spiral resonant cavity comprises the steps of vertically placing a dielectric substrate on a horizontal plane, taking a geometric center point of the dielectric substrate as an origin, setting an axis parallel to the horizontal plane as an x-axis, setting an axis perpendicular to the horizontal plane as a y-axis, and establishing a rectangular coordinate system; setting the central coordinate of the plane square spiral coil as the origin, namely the locating point Z (0, 0), defining a unit as 1mm, translating 5 units to the x-axis negative half axis direction by taking the central coordinate as the origin to obtain a locating point A (-5, 0), translating 5 units to the y-axis positive half axis direction to obtain a locating point B (-5, 5), translating 10 units to the x-axis positive half axis direction to obtain a locating point C (5, 5), translating 10 units to the y-axis negative half axis direction to obtain a locating point D (5, -5), translating 5 units to the x-axis negative half axis direction to obtain a locating point E (0, -5), and sequentially connecting locating points Z, A, B, C, D, E to obtain a first turn of the plane square spiral coil, according to the rule, and sequentially connecting locating points E as the starting point according to a line width of 2mm and a turn-to-pitch of 3mm to obtain locating points of the second, third and fourth turns of the plane square spiral coil, sequentially connecting the locating points in the direction along the xOy plane to obtain a locating point E (0) of the plane spiral coil at the moment, -20) printing a wire with a length of 12mm and a width of 1mm along the negative y-axis direction from the point F to connect the point F of a planar square spiral coil and the point G of a planar circular spiral coil, wherein the coordinate of the point G is G (0-32), the planar circular spiral coil takes the point G as a starting point, the inner diameter is 32mm, the outer diameter is 52mm, the number of turns is 4, the planar circular spiral coil is obtained by rotating and printing along the anticlockwise direction of an xOy plane according to the inner diameter, the number of turns and the turn-to-turn distance, the coordinate of the end point of the planar circular spiral coil is H (0-52), the split ring is positioned on the outermost layer, and the design process is that positioning points I (60-60), J (-60 ), K (-60, 60) and L (60) are sequentially found, the point I, the point J, the point K and the point L form a square with a side length of 120mm, and the split ring is cut along the parallel x-axis direction by taking the split point M (0,60) as the center position of the split ring.

Description

Design method of wireless power transmission system based on spiral resonant cavity Technical Field The invention belongs to the technical field of electromagnetics and wireless power transmission, and particularly relates to a design method of a wireless power transmission system based on a spiral resonant cavity. Background In daily life, charging is very unsafe due to frequent plugging of an electric appliance plug, and particularly, in special occasions such as mining, petroleum exploration, underwater power supply and the like, the traditional power transmission mode has larger potential safety hazard. In recent years, wireless power transmission has received attention. The wireless power transmission technology refers to a power transmission mode in which power is transmitted from a source terminal to a load terminal without using a wire. Wireless power transmission technologies can be classified into inductive coupling, microwave radiation, and magnetic coupling resonance. Inductive coupling is suitable for short-range transmission, while microwave radiation is harmful to human and other living things, and is therefore very limited. Since 2007, a magnetic coupling resonance theory is provided for the first time, and a foundation is laid for the research of various fields of wireless energy transmission. Because no wire is needed, the technology has the advantages of flexibility, convenience, safety and the like. At present, the battery pack is widely applied to aspects of portable electronic products, biomedical equipment, electric automobiles, underwater charging and the like. However, when the charging distance increases, the transmission efficiency of the wireless power transmission system decreases sharply, which is a problem to be solved. The dielectric substrate spiral resonant cavity is a composite material with an artificial design structure and unusual physical properties which are not possessed by natural materials. By designing the unit structure of the dielectric substrate spiral resonant cavity and adjusting the equivalent electromagnetic parameters in a specific frequency range, the dielectric substrate spiral resonant cavity with negative dielectric constant and negative magnetic conductivity electromagnetic characteristics can be obtained. The dielectric substrate spiral resonant cavity with the negative magnetic permeability characteristic can focus the divergent magnetic field and amplify evanescent waves, adjust the magnetic field distribution in a transmission space, and improve the transmission distance and the transmission efficiency of the system. When the dielectric substrate spiral resonant cavity is combined with the wireless power transmission system, changing the position of the dielectric substrate spiral resonant cavity can affect the transmission efficiency of the system. By further analyzing the position of the dielectric substrate spiral resonant cavity, a method for increasing the transmission efficiency is proposed. However, there is currently no report on this aspect. Disclosure of Invention The invention solves the technical problem of providing a design method of a wireless power transmission system based on a spiral resonant cavity, the designed wireless power transmission system effectively solves the problem of increasing transmission distance and reducing efficiency in the wireless power transmission process, a dielectric substrate spiral resonant cavity is added between a transmitting coil and a receiving coil, and the magnetic field distribution and evanescent wave amplification of the wireless power transmission system are changed by moving the position of the dielectric substrate spiral resonant cavity. The invention aims to solve the technical problems by adopting the following technical scheme, the design method of a wireless power transmission system based on a spiral resonant cavity is characterized in that the wireless power transmission system comprises a transmitting coil, a receiving coil, a medium substrate and the spiral resonant cavity arranged on the medium substrate, wherein the transmitting coil and the receiving coil are all plane circular spiral coils and have the same structure, the transmitting coil, the medium substrate and the receiving coil are coaxially and oppositely arranged in sequence, the minimum inner diameter r 1 of the transmitting coil and the minimum outer diameter r 2 of the receiving coil are both 30mm, the maximum outer diameter r 2 of the transmitting coil is both 58mm, the turn distance is 1mm, the number of turns is 7, the spiral resonant cavity is printed on one side of the medium substrate, the spiral resonant cavity consists of a plane square spiral coil, a plane circular spiral coil, an opening ring and a compensation capacitor, the plane square spiral coil, the plane circular spiral coil and the opening ring are sequentially arranged from the center of the medium substrate to the edge of the medium substrate, the