A magnetic field coupling type wireless power transmission system structure

Abstract

The present invention discloses a magnetic field coupling type wireless power transmission system structure, comprising: a transmitting end and a receiving end arranged adjacent to the transmitting end; the transmitting end comprises a DC power supply, an inverter electrically connected to the DC power supply, and a first self-resonant coil electrically connected to the inverter; the receiving end comprises a second self-resonant coil, a rectifier electrically connected to the second self-resonant coil, a filter electrically connected to the rectifier, and a load electrically connected to the filter; the first self-resonant coil and the second self-resonant coil are arranged opposite to each other and spaced apart, and the first self-resonant coil and the second self-resonant coil have the same structure. According to the present invention, the magnetic field coupling type wireless power transmission system can avoid adding a compensation circuit, and the system has low complexity, high efficiency, and stable operation.

Description

Technical Field

[0001] The present invention relates to the technical field of near-field wireless power transmission, and in particular to a magnetic field coupling type wireless power transmission system structure. Background Art

[0002] Magnetic field-coupled wireless power transmission systems are gradually becoming part of people's lives due to their portability, ease of maintenance, and low cost. As a non-radiative wireless power transmission technology, it boasts transmission efficiencies exceeding 80% and high biosafety. In recent years, magnetic field-coupled wireless power transmission has garnered widespread attention in areas such as electric vehicles, personal consumer electronics, implantable medical devices, and specialized applications such as underwater and in mines.

[0003] Magnetic field-coupled wireless power transmission systems require a certain degree of electrical isolation between the transmitting and receiving coils, creating leakage inductance and reactive power circulation, leading to reduced system efficiency. To improve overall system efficiency, compensation capacitors are typically connected in series or parallel to compensate for reactive power. However, during resonance, the voltage or current across the capacitor is Q times the power supply (Q is the system's quality factor), generating an extremely large electric field within the capacitor, which can easily lead to capacitor breakdown or a change in its nominal value, resulting in system instability. Furthermore, adding external compensation capacitors increases system complexity and reduces efficiency. Using the coil's own parasitic capacitance for compensation effectively addresses these issues; such coils are often referred to as self-resonant coils.

[0004] When the transceiver coils in the magnetic field coupling wireless power transmission system are in a resonant state, the transmission efficiency of the system is Where k is the coupling coefficient between the transceiver coils, and Q is the quality factor of the transceiver coils. The product of the inter-coil coupling coefficient k and the coil Q value is the only factor affecting the maximum transmission efficiency between the transceiver coils. In practical applications, the coil size and the transmission distance between the two coils are generally predetermined. In this case, the coupling coefficient k is determined. In this case, the coil Q value becomes the key factor in determining the system's transmission efficiency. The larger the Q value, the greater the system's transmission efficiency. Self-resonant coils avoid the need for external compensation capacitors and have higher Q values ​​than traditional coils. Current research on high-Q self-resonant coils, both domestically and internationally, often conflicts between high Q values ​​and the thickness and complexity of the self-resonant coils. Summary of the Invention

[0005] In order to address the shortcomings of the prior art, the present invention aims to provide a magnetic field coupling wireless power transmission system structure, which can avoid the need for additional compensation circuits and has low system complexity, high efficiency, and stable operation. In order to achieve the above-mentioned purpose and other advantages according to the present invention, a magnetic field coupling wireless power transmission system structure is provided, comprising:

[0006] A transmitting end and a receiving end arranged adjacent to the transmitting end;

[0007] The transmitting end includes a DC power supply, an inverter electrically connected to the DC power supply, and a first self-resonant coil electrically connected to the inverter;

[0008] The receiving end includes a second self-resonant coil, a rectifier electrically connected to the second self-resonant coil, a filter electrically connected to the rectifier, and a load electrically connected to the filter;

[0009] The first self-resonant coil and the second self-resonant coil are disposed opposite to each other and spaced apart from each other. The first self-resonant coil and the second self-resonant coil may have the same or different structures.

[0010] Preferably, the first self-resonant coil includes a single-layer dielectric plate and two first coils and second coils with the same winding direction pressed onto the single-layer dielectric plate, one end of the first coil is connected to a first electrode and the other end is open, one end of the second coil is connected to a second electrode and the other end is open, and the first electrode and the second electrode are respectively located on the inside and outside of the first self-resonant coil.

[0011] Preferably, the first coil and the second coil are two-finger or multi-finger spiral coils, and the first coil and the second coil are made of metal conductors.

[0012] Preferably, the first coil and the second coil are adjacent to each other in that they are connected to different electrodes and are interlaced with each other in the same plane.

[0013] Preferably, the first coil and the second coil can change the coil resonance frequency by changing the finger width and the finger spacing.

[0014] Preferably, the resonant frequencies of the first self-resonant coil and the second self-resonant coil should be the same or similar, and the number of turns, indexes, finger spacing, spiral form, diameter and processing method are all different.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The operating frequency of the high-efficiency self-resonant coil can be adjusted by the coil size, number of turns, finger width and finger spacing: the operating frequency decreases with the increase of the coil size, number of turns and finger width, and increases with the increase of the finger spacing.

[0017] (2) The self-resonant coil can be wound by a wire or processed by a printed circuit board process. The self-resonant coil compensates for reactive power through the parasitic capacitance generated between different fingers of the coil, thereby avoiding the need for external series-parallel compensation capacitors. The coil can be directly connected to the output of the high-frequency inverter circuit and the input of the rectifier circuit. The coil structure is more compact and more reliable, and the wireless power transmission system constructed with the coil is more efficient. Therefore, the present invention is of great significance to the research on miniaturization and lightweighting of magnetic field coupling wireless power transmission systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the self-resonant coil structure of the magnetic field coupling type wireless power transmission system according to the present invention;

[0019] Figure 2 A three-dimensional schematic diagram of the magnetic field coupling type wireless power transmission system according to the present invention;

[0020] Figure 3 FIG. 1 is a graph showing the relationship between the transmission efficiency and the transmission distance of the magnetic field coupling type wireless power transmission system structure according to the present invention. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] Reference Figure 1-3 A magnetic field coupling wireless power transmission system structure includes: a transmitting end and a receiving end arranged adjacent to the transmitting end; the transmitting end includes a DC power supply 6, an inverter 7 electrically connected to the DC power supply 6, and a first self-resonant coil electrically connected to the inverter 7; the receiving end includes a second self-resonant coil, a rectifier 8 electrically connected to the second self-resonant coil, a filter 9 electrically connected to the rectifier 8, and a load 10 electrically connected to the filter 9, and the high-frequency AC power received by the receiving coil is rectified and filtered by the rectifier 8 and the filter 9 to obtain DC power for supply to the load 10; the first self-resonant coil and the second self-resonant coil are arranged opposite to each other and spaced apart, the structures of the first self-resonant coil and the second self-resonant coil are the same or different, the planar spirals of the first self-resonant coil and the second self-resonant coil are Archimedean spirals, and the planar spirals can also be logarithmic spirals, and the planar spirals are manufactured using a printed circuit board process or a flexible circuit board process.

[0023] The planar spiral wires of the first self-resonant coil and the second self-resonant coil are wound using solid metal wire or hollow metal wire, and are wound using 2 to 2000 strands of metal wire. The planar spiral wires of the first self-resonant coil and the second self-resonant coil are wound using enameled metal wire or silk-covered metal wire.

[0024] Furthermore, the first self-resonant coil includes a single-layer dielectric plate 5 and two first coils 1 and second coils 2 with the same winding direction pressed onto the single-layer dielectric plate 5, one end of the first coil 1 is connected to the first electrode 3, and the other end is open, one end of the second coil 2 is connected to the second electrode 4, and the other end is open, and the first electrode 3 and the second electrode 4 are respectively located on the inside and outside of the first self-resonant coil, and the output of the high-frequency inverter 7 is directly connected to the electrodes 3 and 4 at both ends of the transmitting coil, and the electrodes 3 and 4 at both ends of the receiving coil are directly connected to the input of the rectifier 8.

[0025] Furthermore, the first coil 1 and the second coil 2 are two-finger or multi-finger spiral coils, and the first coil 1 and the second coil 2 are made of metal conductors. The first coil 1 and the second coil 2 are pressed together on a single-layer dielectric plate 5 to maintain good mechanical strength, so that they are not easily deformed during use. Parasitic capacitance is generated between adjacent fingers of the coil. The self-inductance value generated by the spiral coil and the parasitic capacitance reach resonance at a certain frequency, thereby avoiding the addition of a compensation circuit and reducing the loss in the wireless power transmission system. At the same time, since the current is distributed in the multi-finger spiral coil, the eddy current loss inside the coil can be reduced, thereby improving the Q value of the coil and increasing the transmission efficiency of the system. Adjusting the distance between adjacent fingers and the finger width can change the size of the parasitic capacitance, thereby changing the self-resonance frequency of the novel coil. In order to obtain a larger parasitic capacitance, the coil index can be greater than 2, and each finger is connected to an electrode at one end and open at one end, but the electrodes connected to adjacent fingers are different.

[0026] Furthermore, the first coil 1 and the second coil 2 are adjacent to each other in that they are connected to different electrodes and are interlaced with each other in the same plane.

[0027] Furthermore, the first coil 1 and the second coil 2 can change the coil resonant frequency by changing the finger width and the finger spacing.

[0028] Furthermore, the resonant frequencies of the first self-resonant coil and the second self-resonant coil should be the same or similar, and the number of turns, indexes, finger spacing, spiral form, diameter and processing method should be the same or different.

[0029] Figure 3This is a graph showing the relationship between transmission efficiency and transmission distance for an example system of the present invention. The system operates at a frequency of 13.56 MHz, with a load of 50 Ω. Both the transmitting and receiving coils have 12 turns and 2 fingers, a Q factor of 313, and a coil thickness of 0.127 mm. Maximum transmission efficiency of 96% is achieved when the coils are 18 mm apart.

[0030] The number of devices and processing scales described herein are intended to simplify the description of the present invention, and applications, modifications, and variations of the present invention will be apparent to those skilled in the art.

[0031] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A magnetic field coupling type wireless power transmission system structure, characterized in that: include: A transmitting end and a receiving end arranged adjacent to the transmitting end; The transmitting end comprises a direct current power supply (6), an inverter (7) electrically connected to the direct current power supply (6), and a first self-resonant coil electrically connected to the inverter (7); The receiving end comprises a second self-resonant coil, a rectifier (8) electrically connected to the second self-resonant coil, a filter (9) electrically connected to the rectifier (8), and a load (10) electrically connected to the filter (9); The first self-resonant coil and the second self-resonant coil are arranged opposite to each other and spaced apart from each other, and the first self-resonant coil and the second self-resonant coil have the same or different structures. The first self-resonant coil comprises a single-layer dielectric plate (5) and two first coils (1) and second coils (2) with the same winding direction pressed onto the single-layer dielectric plate (5); one end of the first coil (1) is connected to a first electrode (3) and the other end is open-circuited; one end of the second coil (2) is connected to a second electrode (4) and the other end is open-circuited; and the first electrode (3) and the second electrode (4) are respectively located on the inner side and the outer side of the first self-resonant coil; The first coil (1) and the second coil (2) are adjacent to each other and are connected to different electrodes and are interlaced in the same plane.

2. A magnetic field coupling type wireless power transmission system structure as claimed in claim 1, characterized in that: The first coil (1) and the second coil (2) are two-finger or multi-finger spiral coils, and the first coil (1) and the second coil (2) are made of metal conductors.

3. The magnetic field coupling type wireless power transmission system structure as claimed in claim 1, characterized in that: The first coil (1) and the second coil (2) can change the coil resonance frequency by changing the finger width and the finger spacing.

4. The magnetic field coupling type wireless power transmission system structure as claimed in claim 1, characterized in that: The resonant frequencies of the first self-resonant coil and the second self-resonant coil should be the same or similar, and the number of turns, index, finger spacing, spiral form, diameter and processing method should be the same or different.

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