CN112769248B

CN112769248B - Close-range one-to-many wireless charging device and system

Info

Publication number: CN112769248B
Application number: CN202110371909.8A
Authority: CN
Inventors: 李谦
Original assignee: Xi'an Dianche Fengyun Intelligent Technology Co ltd
Current assignee: Xi'an Dianche Fengyun Intelligent Technology Co ltd
Priority date: 2021-04-07
Filing date: 2021-04-07
Publication date: 2021-07-16
Anticipated expiration: 2041-04-07
Also published as: CN112769248A

Abstract

The invention discloses a close-range one-to-many wireless charging device and a close-range one-to-many wireless charging system, wherein the wireless charging device comprises a transmitting coil arranged on a base body, the transmitting coil is formed by winding a single metal wire from outside to inside, and after a central area is short-circuited, the transmitting coil is wound from inside to outside in opposite directions continuously at one time; and one wire enters and the same wire exits, and the current directions of each turn of the wire and the adjacent turn of the wire are opposite. The invention does not need coil superposition, greatly reduces the volume and the weight, keeps a smooth and uniform near field and almost has no blind area, so that the receiving equipment can be randomly spliced on the charging flat plate, the cost is greatly reduced, and the control stability, the charging efficiency and the applicability are improved.

Description

Close-range one-to-many wireless charging device and system

Technical Field

The invention belongs to the technical field of inductive power, and relates to a short-distance one-to-many wireless charging device and system.

Background

The coil that current most wireless charging device adopted mainly uses QI technical standard: the coil and the magnetic core are combined to improve the transmission efficiency.

At present, the wireless power manufacturer generally adopts a Qi type coil module from a foreign manufacturer by the public confidence of Qi, and the Qi type coil module is necessarily used as a reference, so that even if the coil is customized, the multi-turn coil of the coil manufacturer is often directly used; it is also obvious from the papers and published patents that most of the technical solutions are realized by optimizing the arrangement of coil modules based on Qi-type coil modules and multi-turn coils. Due to the limitation of the practical problems in the industry, the creation difficulty of improving the performance of the wireless charging device by optimizing the coil is greatly increased, and the development of a new scheme is hindered.

Prior art 1 (patent application publication No. CN 110571031A) discloses a wireless charging transmitting coil, which includes at least two coil wiring layers stacked up and down, each coil wiring layer includes a plurality of coils disposed on the same plane; each coil in the current coil wiring layer is respectively arranged in each charging blind area of other coil wiring layers; the utilization rate of the wireless charging transmitting terminal is improved through the stacking of the multiple coils. This solution requires a stack of many QI standard kHz independent coils, two wires per coil, with many pairs of wires in a large array.

Prior art 2 (patent application publication No. CN 105723479A) discloses a transmitter for an inductive power transfer system having a plurality of transmitting coils for generating an alternating magnetic field, the transmitting coils being arranged in a row by each transmitting coil partially overlapping with adjacent transmitting coils in the row, a transmitting circuit connected to each transmitting coil being capable of driving the transmitting coils so that the alternating magnetic field of each transmitting coil is phase-shifted with respect to the alternating magnetic field of adjacent transmitting coils in the row or so that the alternating magnetic field generated by the transmitting coils is translated along a charging surface. Because each transmitting coil is partially overlapped with the adjacent transmitting coils in the row, the hollow area of each transmitting coil is shielded by the adjacent transmitting coils, and the magnetic field of the vertical area of each transmitting coil is greatly influenced; when the transmitting coil generates an alternating magnetic field to translate along the charging surface, the magnetic fields in the vertical area and the horizontal area of the transmitting coil are difficult to align, so that the coupling power is greatly reduced.

The above prior art has had to employ an overly complex, stacked process and has not necessarily been properly handled. It is difficult to turn the "circular magnetic field" generated by the plurality of coils into a magnetic field close to the vertical, and a blind area still exists. In addition, each coil requires a digital control module, and the more coil modules, the more ports required for control, transmission and protocol processing. Thus, the hardware requirement is high, the bug can be easily generated along with the system firmware, more time and labor are needed for processing, and the cost and the design difficulty of the whole central control module are increased.

Most of the prior art is designed by using a high-density red copper wire coil and a multi-layer composite compact lamination mode. For fast charging, the high-density structure is easy to heat due to large heat dissipation capacity, and a heat dissipation structure is needed. In addition to cost, complexity, there are weight and handling issues. In a small wireless charging plane board, the more complicated splicing of the structure and the modules represents more delicate structure carelessness, and in addition, the plastic material is required to be used much more by applying a magnetic field, and the stacked technical crystal is not durable. Various fault problems are easily derived, and in order to avoid the problems, manufacturers generally reduce transmission power, cool at a layer invisible to users and increase stability; resulting in difficulty in achieving the design power in practical applications.

Disclosure of Invention

In order to solve the problems, the invention provides a close-range one-to-many wireless charging device and a close-range one-to-many wireless charging system, which do not need to overlap coils, greatly reduce the volume and the weight, simultaneously keep a smooth and uniform near field, and almost have no blind area, so that receiving equipment can be randomly spliced on a charging flat plate, the cost is greatly reduced, the control stability, the charging efficiency and the applicability are improved, and the problems in the prior art are solved.

The technical scheme adopted by the invention is that the short-distance one-to-many wireless charging device comprises a transmitting coil arranged on a base body, wherein the transmitting coil is formed by winding a single metal wire from outside to inside, and after a short circuit occurs in a central area, the transmitting coil is wound from inside to outside in opposite directions continuously at one time; one wire enters and the same wire exits, and the current direction of each turn of the wire is opposite to that of the adjacent tamping wire.

Further, the central short-circuit area of the coil is symmetrical about the center of the coil, and the coil distance A of the central short-circuit area of the coil is more than 30-50% of the coil distance B of the adjacent coil of the non-central area.

Furthermore, the line width of the coil is 3-7mm, the distance B between adjacent coils in the non-central area of the coil is 16-25mm, and the number of turns of the coil wound from outside to inside is 1-10.

Furthermore, the single metal wire is wound from outside to inside, and after the short circuit occurs in the central area, the single metal wire is wound from inside to outside in the opposite direction close to the wound coil continuously at one time.

Furthermore, the distance between adjacent coils with the same coil current direction, which is obtained by winding the single metal wire from outside to inside, is 6-80mm, the line width is 3-7mm, and the number of turns is 1-10.

Further, the effective density of the magnetic field generated by the transmitting coil is within 40mm of the substrate.

Furthermore, the coil is rectangular, other regular polygons or circular, the turn of the coil is a fillet or a right angle, and the line width of the turn of the coil is consistent with the line width of the turn of the coil.

Further, the surface of the substrate is coated with a metal layer.

Further, the substrate is FR-4 or PCB.

A wireless charging system comprises the short-distance one-to-many wireless charging device.

The invention has the beneficial effects that:

1. the transverse magnetic field of the transmitting coil array is far more than that of a straight region magnetic field, the transmitting coil array enters one line and exits the same line, and the transmitting coil array can be regarded as a single-wire coil, and is a short-circuit bifilar coil (English). The smooth and uniform near-field magnetic field can be obtained without coil superposition, the whole thickness of the transmitting coil is very thin, and the volume, the weight and the cost are greatly reduced; since the superposition of the coil on the PCB means doubling the PCB substrate layers so that the cost will increase substantially.

2. The invention only needs one driving source, has simple and convenient design loop, reduces the complexity, the engineering pressure and the post-manufacturing cost, simultaneously improves the stability and reduces the loss.

3. For more than ten years, the scientific research community focuses on pushing away an electromagnetic field and making the distance longer, the invention pulls back a strong magnet to the board surface, which is not the conventional operation in the field because the electromagnetic far field phenomenon belongs to a cancellation mode (field cancellation), and the electromagnetic field cancellation is reduced or reduced as much as possible in the existing research. The invention uses the transverse field of the single-sided circuit to shape the smooth near magnetic field, keeps the magnetic field smooth and uniform, allows the near field transmission of mm grade, and fills the blank of the prior art. The receiving equipment can be spliced on the charging panel at will without a blind area, is easier to expand, can be handled without a radio frequency plate, greatly reduces the cost, simplifies the production difficulty, improves the applicability and is more beneficial to large-scale popularization.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural view of each set of coils in embodiment 1 of the present invention.

Fig. 2 is a vector diagram of a simulated magnetic field of the surface of the transmitting coil in embodiment 1 of the present invention.

Fig. 3 is a cross-section simulated magnetic field vector diagram of the transmitting coil in embodiment 1 of the present invention.

Fig. 4 is a cross-section simulated magnetic field vector diagram of the transmitting coil of embodiment 2 of the present invention.

Fig. 5 is a structural view of a transmitting coil in comparative example 1 of the present invention.

Fig. 6 is a cross-section simulated magnetic field vector diagram of the transmitting coil of comparative example 1 of the present invention.

Fig. 7-8 are simulated magnetic field vector diagrams for different coil spacings in accordance with embodiments of the present invention.

Fig. 9 is a vector diagram of a simulated magnetic field of the surface of the transmitting coil in embodiment 3 of the present invention.

Fig. 10 is a cross-section simulated magnetic field vector diagram of the transmitting coil in embodiment 3 of the present invention.

Fig. 11 is a schematic structural view of a transmitting coil in embodiment 4 of the present invention.

Fig. 12 is a cross-section simulated magnetic field vector diagram of the transmitting coil in embodiment 4 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the case of the example 1, the following examples are given,

a close-range one-to-many wireless charging device comprises a transmitting coil, wherein the transmitting coil is formed by winding a single metal wire from outside to inside, and after a short circuit occurs in a central area, the transmitting coil is wound from inside to outside in opposite directions continuously at one time to form a fret pattern texture similar to 'richness and inexistence'; this loop is one in, one out, so that the current direction is opposite for each turn and adjacent turns, as shown in fig. 1-2.

The transmitting coil is arranged on the substrate, and one wire is continuously shown at one time, so that the whole large substrate is a coil loop, unlike the Qi type coil in which each coil is laminated by a layer of litz wire, a layer of glue, another layer of magnetic chip, another layer of plastic or metal interlayer and the like.

In some embodiments, the central short-circuited region of the coil in fig. 1 is symmetric about the center of the coil, the surrounding magnetic field is divided by the average, and the central short-circuited region is shown in dashed outline in fig. 1. The coil distance A of the central short circuit area of the coil is 30-50% larger than the adjacent coil distance B of the non-central area; if the center short-circuit area coil spacing a is too small, the overall magnetic field will be concave down the center. The distance A between the central short-circuit areas is too large and is too convex; similarly, the layout of the pitch B is also fine-tuned through long-time simulation to achieve the required degree of balance and transmission distance.

In some embodiments, the coil is rectangular or any other polygonal shape, requiring the shape of each direction to be consistent, such as regular pentagons, regular hexagons, and so on to approximate a circle. The coil can not have unsmooth or other non-regular bendings, can influence the magnetic field average degree, causes uneven blind area. The magnetic field of the straight line is uniform on average, and at each turning point, for example, turning to the left, the magnetic field before and after the turning opening at the left side is gained, and the magnetic field at the right side is discounted. In some embodiments, the turns of the coil in fig. 1 are rounded or square, which requires that the width of the turn be consistent with the width of the straight line.

In the embodiment 1 of the invention, strong magnetic is pulled back to the plate surface, and if the magnetic field is offset too much, the density of the transmitted electric energy is insufficient. The coil of example 1 has two adjustment parameters of maximum influence, namely the spacing and the line width between each turn of the coil, and the magnetic field density as shown in fig. 3 (standard median cross section) is obtained through optimization and teaching according to the required plate type and transmission distance. The part of the figure 3, which is circled by the dotted line, is the degree of the most suitable wireless power coupling, and the most average, the effective density (the magnetic field density is more than 5A/m) is concentrated in a few mm to 10mm, even 40mm of the board table surface, and the most suitable distance for plane transmission is; the distance of the effective density is determined according to the maximum distance B in the used plate frame; the effective distance is generally 0 to 1.5 multiplied by B mm by actually measuring with a receiving end with the length and the width of 50mm, and a larger receiving end can have a transmission distance which is a bit longer. The extended sparse magnetic field is not suitable for high power transmission (below 10W) and may be sufficient for microwatt applications. The spacing and width between each turn may be large or small, which may affect the uniformity and transmission distance of the magnetic field distribution. In the one-to-many wireless charging application, the magnetic field is smooth and average, which is crucial because a user can place many household appliances on a transmitting plane, and only the average magnetic field can be applied to avoid receiving end abnormity or damage caused by excessively strong magnetic field in some areas. Depending on the characteristics of the multi-turn coil, there are inevitably regions of insufficient uniformity in the electromagnetic near field, no matter how the arrangement is designed.

In the case of the example 2, the following examples are given,

the metal layer is coated on the surface of the base body, and the magnetic field is from the single-sided copper-clad base body (copper-clad plate), so that the magnetic field passing through the base plate is less, and the influence of the tangent loss of the base plate on the transmission efficiency of the wireless charging device is reduced. The thickness of the copper layer is 1-5 Ounces (OZ). In some embodiments, the substrate adopts FR-4 or PCB, which can realize high-efficiency electric energy transmission; the surface of the substrate is coated with a metal layer. In some embodiments, the copper-clad plate does not need solder mask; higher performance can be achieved by silver deposition.

In embodiment 2, the simulated magnetic field of the wireless charging device with the copper-clad plate as the substrate is shown in fig. 4 (standard right center cross section), and the black line on the right side of the drawing is the metal layer, so that the magnetic field is separated and the other side is shielded.

The coil line width is 3mm, the distance B between adjacent coils in the non-central area of the coil is 16mm, and the number of turns of the coil wound from outside to inside is 4; as shown in fig. 7 (standard right-center cross section), the magnetic field is uniform, effective wireless power transmission can be realized, and the ratio of the line width to the space is not appropriate, so that efficient wireless transmission is difficult to obtain. The coil line width is 4mm, the distance B between adjacent coils in the non-central area of the coil is 25mm, and the number of turns of the coil wound from outside to inside is 4; as shown in fig. 8 (standard right-center cross section), the near-field magnetic field can be pushed away compared to fig. 7; the black small boxes represent the input ports because of the hardware, the port area is weaker in magnetic field.

In the case of the example 3, the following examples are given,

the structure is shown in fig. 9, the structure of the embodiment 3 is similar to that of the

embodiments

1 and 2, the distance between adjacent coils with opposite current directions in fig. 9 is 8mm, the line width is 4mm, and the number of turns of the coil wound from outside to inside is 3; as a result of the simulation, as shown in fig. 10 (a cut plane on the right vertical line), the magnetic field distribution at the edge of fig. 10 is smoother than the simulation results of fig. 3 and 4.

In the case of the example 4, the following examples are given,

the locations indicated by the black arrows in fig. 10 (i.e., the dashed channels) are relatively weak magnetic field regions that are not nonmagnetic black regions as in conventional coil designs, but are relatively weak, i.e., the recesses in fig. 10. The structure of the transmitting coil is further improved on the basis of the embodiment 3, the structure is shown in fig. 11, a single metal wire is wound from outside to inside, and after the short circuit occurs in the central area, the transmitting coil is wound from inside to outside in the opposite direction continuously and once as close as possible to the wound coil; in fig. 11, a single metal wire is wound from outside to inside, the distance between adjacent coils in the same current direction is 16mm, the line width is 3mm, the number of turns is 3, and the distance D is 0.2 mm. The coil is designed in a custom PCB area and the distance D to the wound coil must be the minimum pitch within typical PCB industry production capacity and the pitch C must be the maximum pitch that can be achieved at the selected number of turns, the pitch C being 20-30mm in this example.

Example 4 the coils on both sides of the weak magnetic field in example 3 were pulled as close as possible, the magnetic fields on both sides of the weak magnetic field were merged, and the simulation result of example 4 is shown in fig. 12 (cut on the right vertical line), where the weak magnetic field density is close to that of the strong magnetic field. Meanwhile, the magnetic field in the middle area of fig. 12 is smoother and more uniform. The smoothness and the uniformity of the magnetic field are key quality judgment indexes of plane wireless energy transmission, and through repeated experiments, each direction on the surface is electrified, the difference of receiving voltage of each inch is not large, the fluctuation range of the receiving power is within 20 percent, and the level of the fluctuation range is the same as the performance error of an inductance device; it can be seen that the generated magnetic field has no dead or weak area on the side of the receiving end.

TABLE 1 Experimental data for effective Density magnetic field distance from substrate for different sizes

As can be seen from Table 1, examples 2 and 4 can both concentrate the effective density within 40mm of the substrate, effectively maintain the uniformity of the magnetic field and control the thickness of the magnetic field. The line width of each coil turn in the embodiment 2 is to adjust the current intensity, a wide line is needed for a high current, the distance between each coil turn affects the thickness of the near field, and the magnetic field distribution uniformity is easily reduced due to the excessively large distance, which is greatly improved in the embodiment 4. The spacing range of the adjacent coils in the embodiment 4 is wider, the magnetic field density of the weak region close to the strong region is realized, and meanwhile, the magnetic field in the middle region is smoother and better in uniformity.

The invention is very easy to control and design after optimizing the parameters. Can be used in the MHz and kHz bands without imposing design frequency limitations. Compared with a common module combination mode, the embodiment of the invention is simpler, only the resonance frequency needs to be adjusted and a power amplifier is added, and energy can be received according to the resonance area as long as the resonance frequency is the same regardless of the size of a receiving end.

The overall size of the transmitting coil in embodiments 1-4 can be scaled according to 1:2, 1:3, 1:4 or 1:5, and optimization and adjustment are still needed after scaling; the size of the substrate may be any of 20X 20mm, 40X 40mm, 60X 60mm, 100X 100mm or 200X 200 mm. The PCB can be a full PCB process, and has a simple structure and an integrated design; the size of the specification is increased or decreased according to the number of turns.

In the case of the example 5, the following examples were conducted,

a wireless charging system comprises the short-distance one-to-many wireless charging device. The structures and shapes of the receiving coil and the transmitting coil are not necessarily consistent, and the magnetic field resonance comes from a structure body, but both are still in the density range and the resonance frequency band, so that the transmission still exists and is effective.

Prior art 3 (a transmitting coil for realizing a wireless charging plane constant voltage charging), a coil generates a magnetic field in one direction as a current by a plurality of turns, and then in the other direction at a distance. In this case, then, the magnetic field is in the same direction if it is close to the table, so that prior art 3 states that the vertical separation D ≧ 0.25a (a is 20 cm), with a more uniform magnetic field distribution. The present invention concentrates the surface near field on the surface and is fully available. This is because the entire area is covered by the calculated positive and negative current magnetic fields, as in the magnetic field distribution of fig. 2.

In the comparative example 1,

the double-wire coil structure is shown in fig. 5, the current flow directions of adjacent coils are opposite, two coils are used, two driving sources are needed, the simulated magnetic field is shown in fig. 6 (standard right center cross section), the magnetic field is pushed out to form a circular arc, and the double-wire coil structure is difficult to be suitable for mm-grade near field transmission.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A close-range one-to-many wireless charging device is characterized by comprising a transmitting coil arranged on a base body, wherein the transmitting coil is formed by winding a single metal wire from outside to inside, and after a short circuit occurs in a central area, the transmitting coil is wound from inside to outside in opposite directions continuously at one time; one wire is fed in and the same wire is discharged out, and the current directions of each turn of conducting wire and the adjacent turns of conducting wires are opposite;

the central short circuit area of the coil is symmetrical about the center of the coil, and the coil distance A of the central short circuit area of the coil is 1.3-1.5 times of the coil distance B of the adjacent coil in the non-central area;

the coil line width is 3-7mm, the distance B between adjacent coils in the non-central area of the coil is 16-25mm, and the number of turns of the coil wound from outside to inside is 1-10;

the magnetic field of effective density generated by the transmitting coil is within 40mm from the substrate.

2. The short-range one-to-many wireless charging device according to claim 1, wherein the single metal wire is wound from outside to inside and is wound from inside to outside in opposite directions consecutively in proximity to the wound coil once after the short circuit in the central region.

3. The close-range one-to-many wireless charging device according to claim 2, wherein the distance between adjacent coils, which are wound from outside to inside by a single metal wire and have the same coil current direction, is 6-80mm, the line width is 3-7mm, and the number of turns is 1-10.

4. The close-range one-to-many wireless charging device according to claim 1, wherein the coil is rectangular, other regular polygon or circular, the turn of the coil is a rounded corner or a right angle, and the line width of the turn of the coil is consistent with that of a straight line.

5. The close-range one-to-many wireless charging device according to claim 1, wherein the surface of the base body is coated with a metal layer.

6. The close-range one-to-many wireless charging device according to claim 1, wherein the substrate is FR-4 or PCB.

7. A wireless charging system comprising a close-range one-to-many wireless charging apparatus according to any one of claims 1 to 6.