WO2018188202A1

WO2018188202A1 - New wireless electric energy transmission magnetic path coupling mechanism

Info

Publication number: WO2018188202A1
Application number: PCT/CN2017/091608
Authority: WO
Inventors: 夏晨阳; 任思源; 郑凯; 刘利民; 朱从; 朱文婷; 陈锐; 马念
Original assignee: 中国矿业大学
Priority date: 2017-04-11
Filing date: 2017-07-04
Publication date: 2018-10-18
Also published as: CA3031438C; CA3031438A1; CN107170570A; CN107170570B

Abstract

Proposed in the present invention is a new wireless electric energy transmission magnetic path coupling mechanism, comprising: a primary side energy emission cushion and a secondary side energy collection cushion arranged opposite and in parallel with each other. The primary side energy emission cushion and the secondary side energy collection cushion are both of a two-layered structure, with one layer being a coil layer formed by winding a Litz wire, and the other layer being a magnetic core layer. The coil layer and the magnetic core layer are both of a centrosymmetric structure. The coil layer comprises two identical orthogonally laminated rectangular coils, and the magnetic core layer is a Sudoku-shaped grid layer comprising eight ferrite strips with the same length. The length of the ferrite strips is equal to the length of the rectangular coils. The coil layers of the primary side energy emission cushion and the secondary side energy collection cushion are opposite each other, and opposite surfaces of the primary side energy emission cushion and the secondary side energy collection cushion are in mirror symmetry with each other. The mechanism has a higher coupling coefficient, and a wider deviation allowance range can be simultaneously provided in three directions, such as two horizontal directions perpendicular to each other and a direction of rotation around a central axis of the mechanism.

Description

Novel radio energy transmission magnetic circuit coupling mechanism

Technical field

The present invention relates to the field of radio energy transmission technologies, and in particular, to a novel radio energy transmission magnetic circuit coupling mechanism.

Background technique

The wireless energy transmission technology is a new power access mode that realizes the transmission of electrical energy from a source device to a powered device under full electrical isolation by means of a space invisible soft medium (such as a magnetic field, an electric field, a laser, a microwave, etc.). This technology fundamentally eliminates the problems of device wear, poor contact, and contact spark caused by the traditional "socket + connector" power supply mode. It is a clean, safe and flexible new power supply mode. It is published by the US Technical Review. Selected as one of the top ten research directions in the future.

Among them, the wireless energy transmission magnetic circuit coupling mechanism is the key to the difference between the wireless energy transmission technology and the traditional wired power transmission form. Its performance also indicates the advantages and disadvantages of the radio transmission system, so the wireless energy transmission magnetic circuit coupling mechanism Research becomes very important. The most important indicator to measure the performance of the wireless energy transmission magnetic coupling mechanism is the coupling coefficient k, which can consider the coupling degree of a magnetic circuit mechanism. In practice, it is generally between 0.01 and 0.5. The larger the k value, the closer the magnetic circuit mechanism is coupled. The magnetic circuit coupling mechanism is more efficient. Since the primary side energy emitting pad of the wireless energy transmitting magnetic circuit coupling mechanism and the secondary side energy picking pad have a large air gap for non-contact, the secondary side energy picking pad and the primary side energy emitting pad are difficult to face, The relative position of the magnetic circuit coupling mechanism with a wider offset tolerance range is more practical. There may be many offset positions between the primary side energy emitting pad and the secondary side energy picking pad, so for the convenience of research, generally select two mutually perpendicular horizontal directions coplanar with the secondary side energy picking pad and rotate around the central axis. The offset direction is used to study the anti-offset characteristics of the magnetic circuit coupling mechanism, and the arbitrary displacement of the magnetic circuit coupling mechanism can be realized by superimposing the above three offset directions. In particular, a larger coupling coefficient k can provide a wider range of offset tolerance.

There are many studies on the magnetic energy transmission magnetic coupling mechanism, but in the related art, the DD type magnetic circuit coupling mechanism proposed by the University of Auckland is widely used due to its own good characteristics. The DD type magnetic circuit coupling mechanism is developed by a "magnetic tube" type magnetic circuit coupling mechanism, but compared with the latter, the former provides only a single side magnetic flux path in the air, and the other side magnetic flux path is matched. The ferrite strips form a closed path, so they have a large coupling coefficient in the case of the same gap. At the same time, the DD-type magnetic circuit coupling mechanism has a good offset tolerance in the direction of its ferrite strip, and its tolerance in the direction parallel to its ferrite bar and rotation around the center of the mechanism is poor.

Summary of the invention

OBJECT OF THE INVENTION The object of the present invention is to provide a novel radio energy transmission magnetic circuit coupling mechanism which not only has a higher coupling coefficient, but also can rotate in two mutually perpendicular horizontal directions and around the central axis of the mechanism. Provides a wider range of offset tolerance in the direction.

Technical Solution: In order to achieve the above technical effects, the present invention proposes the following technical solutions:

A novel radio energy transmission magnetic circuit coupling mechanism, comprising: a primary side energy emitting pad and a secondary side energy picking pad, the primary side energy emitting pad and the secondary side energy picking pad are oppositely arranged and parallel to each other; primary side energy emission The pad and the secondary energy pick-up pad are of a two-layer structure, one of which is a coil layer wound by a Litz wire, and the other layer is a core layer; the coil layer and the core layer are both centrally symmetric; The coil layer is composed of two identical rectangular coils stacked orthogonally, and the core layer is a nine-grid grid layer composed of eight ferrite strips of equal length; the primary side energy emitting pad and the secondary side energy picking pad The coil layers are opposite, and the opposite sides of the primary side energy emitting pad and the secondary side energy picking pad are mirror symmetrical with each other.

Further, the length of the ferrite strip is equal to the length of the rectangular coil.

Further, among the four ferrite strips in the middle of the magnetic core layer, the positions of any two parallel ferrite strips satisfy the following conditions:

w=0.2a

Where w represents the outer margin of two mutually parallel ferrite bars; a represents the length of the rectangular coil.

Further, the ratio of the width to the length of the rectangular coil is 0.7.

Advantageous Effects: Compared with the prior art, the present invention has the following advantages:

The novel radio energy transmission magnetic circuit coupling mechanism of the present invention is an excellent magnetic circuit coupling structure, which has a higher coupling coefficient than the related art, and can simultaneously be in two mutually perpendicular horizontal directions and Provides a wider offset tolerance range in three directions, such as the rotation of the central axis of the mechanism, and provides a more diverse selection of magnetic circuit coupling mechanisms for the selection of the magnetic path coupling mechanism of the wireless energy transmission system.

DRAWINGS

1 is a schematic structural view of Embodiment 1;

2 is a schematic diagram of a winding mode and key parameters of a primary side energy emitting pad in Embodiment 1;

3 is a model diagram of a magnetic circuit coupling mechanism in the prior art;

4 is a comparison diagram of the air gap distance tolerance characteristics of the DD type and the cross type coupling mechanism of the first embodiment under the same conditions;

Figure 5 is a comparison diagram of the tolerance characteristics of the center rotation angle under the same conditions of the DD type and the cross type coupling mechanism of the first embodiment;

6 is a comparison diagram of the horizontal offset distance tolerance characteristics of the DD type and the cross type coupling mechanism of the first embodiment under the same conditions;

7 is a schematic structural view of a ferrite core layer of the cross-type magnetic circuit coupling mechanism according to Embodiment 1 in five different schemes;

8 is a comparison chart of the relationship between the coupling coefficient k and the c of the cross-type magnetic circuit coupling mechanism of Embodiment 1 when a is different and q=0.5 under the condition of a breath distance of 200 mm and n=10 ;;

9 is a comparison diagram of the relationship between the coupling coefficient k and the c of the cross-type magnetic circuit coupling mechanism of the first embodiment when q is different and a=600 mm under the condition of a breath distance of 200 mm and n=10 ;;

10 is a schematic view showing the structure and parameters of a ferrite core layer in Embodiment 2;

Figure 11 is a graph showing the relationship between the coupling coefficient k and q when a is taken to a different value under the condition of n = 10 匝 and a breath distance of 200 mm according to the second embodiment;

Figure 12 is a graph showing the relationship between the coupling coefficient k and q when the breath distance takes different values under the condition of n = 10 匝 and a = 600 mm according to the cross-type coupling mechanism of the second embodiment;

13 is a cross-type coupling mechanism according to Embodiment 2, in which a=600 mm and a breath distance of 200 mm, q changes from 0.5 to 1 in steps of 0.01, and the number of rectangular coil turns is from 10 to 10 in steps of 10 The variation of k with c in 30 cases formed by 30匝 change;

Figure 14 is an optimum ferrite core structure shown in Figure 16 and under the premise of a = 600 mm and Air gap = 200 mm, the number of rectangular turns n is 10 匝, 20 匝, 30 分别, respectively. Curve with q;

Fig. 15 is a configuration diagram of the third embodiment.

In the figure: 101, a first coil layer, 102, a first core layer 201, a second coil layer, 203, and a second core layer.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

Embodiment 1 FIG. 1 is a structural diagram of Embodiment 1 of the present invention, including: a primary side energy emitting pad and a secondary side energy picking pad; wherein the primary side energy emitting pad includes a first coil layer 101 and a first magnetic layer The core layer 102, the first coil layer 101 is placed over the first core layer 102; the secondary side energy pickup pad comprises a second coil layer 201 and a second core layer 202, and the second coil layer 202 is placed on the second core layer Below 202.

The first coil 101 and the second coil 201 are each composed of two identical rectangular coils stacked in an orthogonal manner. Rectangular coil They are all wound by the Litz wire.

The first core layer 102 and the second core layer 202 are each composed of eight ferrite strips arranged vertically and horizontally, and the first core layer 102 and the second core layer 202 are entirely centrally symmetric.

The outer length of the first/second core layer 102/202 is equal to the length of the first/second coil 101/201.

The primary side energy transmitting pad of the novel wireless energy transmission magnetic circuit coupling mechanism of Embodiment 1 has the same structure as the secondary side energy picking pad, and the winding method is also the same. Taking the primary energy emission pad as an example, the winding mode and key parameters are as shown in FIG. 2: the first coil 101 and the first core layer 102 are formed, and the overall structure is center-symmetrical. The first coil 101 is composed of two identical rectangular coils stacked in an orthogonal manner. Therefore, the magnetic circuit coupling mechanism of the present invention is also referred to as a cross-type magnetic circuit coupling mechanism, and the winding manner is as shown by an arrow in FIG. In order to further explain the optimized structure of the magnetic circuit coupling mechanism, the side length of the ferrite core layer and the length of the rectangular coil are defined as a, and the width of the rectangular coil is defined as b, the number of turns is n, and the core layer ferrite The strip is made of a MnZn ferrite strip material having a width of 30 mm and a thickness of 20 mm. The outer margin of the middle ferrite strip is defined as w. Meanwhile, the ratio of b to a is defined as q, and the ratio of w to a is c.

FIG. 3 shows a magnetic circuit coupling mechanism which is relatively common in the prior art and has excellent performance. It is generally referred to as a DD type magnetic circuit coupling mechanism, and is a cross type magnetic circuit coupling mechanism and a DD type magnetic circuit coupling mechanism in Comparative Example 1. Performance, making a cross-type magnetic circuit coupling mechanism of the same size (600*600mm), the same Litz wire length (65.6m), and the same rectangular coil turns (10匝) as the DD type magnetic circuit coupling mechanism shown in Fig. 3. As shown in Figure 1. In Fig. 3, the DD type magnetic circuit coupling mechanism uses a 5760 cm ³ volume ferrite material, and the coupling coefficient is 0.21 under an air gap of 200 mm, and the cross type magnetic circuit coupling mechanism uses only a ferrite material of 5184 cm ³ volume. The coupling coefficient reached 0.2439 at an air gap of 200 mm.

4 to FIG. 6 are further comparison diagrams of the tolerance of the cross-type magnetic circuit coupling mechanism and the DD-type magnetic circuit coupling mechanism under the above conditions, wherein FIG. 4, FIG. 5 and FIG. A comparison of the three coupling characteristics of the coupling coefficient of the path coupling mechanism to the air gap distance, the central rotation angle, and the horizontal offset distance.

The curve (1) and the curve (2) in Fig. 4 are the relationship between the coupling coefficient k and the breath distance of the cross-type magnetic circuit coupling mechanism and the DD-type magnetic circuit coupling mechanism, respectively, and it can be clearly seen that the breath is in the range of 100 mm to 250 mm. The cross-type magnetic circuit coupling mechanism in the range is more advantageous than the DD-type magnetic circuit coupling mechanism.

The curve (3) and the curve (4) in Fig. 5 are the relationship between the coupling coefficient k and the central rotation offset angle of the cross-type magnetic circuit coupling mechanism and the DD-type magnetic circuit coupling mechanism at a breath distance of 200 mm, respectively. The coupling coefficient k of the DD type magnetic circuit coupling mechanism fluctuates greatly with the increase of the central rotation angle. Especially at 0° and 180°, the k value takes the maximum value and approaches the 0 at 90° and 270°. This brings stability to the entire wireless energy transmission system. A great problem is that, in comparison, the coupling coefficient of the cross-type magnetic circuit coupling mechanism is basically unchanged when the central rotation offset occurs, and its stability value is greater than the coupling coefficient of the DD-type magnetic circuit coupling mechanism.

The curve (5) in Fig. 6 shows the coupling coefficient curve of the cross-type magnetic circuit coupling mechanism horizontally offset in the cross or y direction. Since the cross-type magnetic circuit coupling mechanism is centrally symmetrical, the horizontal offset tolerance characteristic in the cross or y direction Similarly, there is only one curve (5) in Fig. 6, and for the DD type magnetic circuit coupling mechanism, the horizontal offset tolerance characteristics in the cross and y directions are different, so they are represented by curves (6) and (7), respectively. It can be seen that the offset tolerance characteristic of the DD type magnetic circuit coupling mechanism in the cross direction is earlier than that in the y direction, and a blind spot (a point where k is 0) occurs when the cross direction is shifted by 220 mm, and the cross type The horizontal offset tolerance characteristic of the magnetic circuit coupling mechanism in the cross or y direction is better than the offset tolerance characteristic of the DD type magnetic circuit coupling mechanism in the cross direction, and the cross type magnetic circuit is shifted in the y direction by a distance of 0-135 mm. The coupling coefficient of the coupling mechanism is larger than the DD type magnetic circuit coupling mechanism. When the offset distance in the y direction is greater than 135 mm, the coupling coefficient of the DD type magnetic circuit coupling mechanism is larger than that of the cross type magnetic circuit coupling mechanism.

In summary, the cross-type magnetic circuit coupling mechanism of the present invention is an excellent magnetic circuit coupling structure, which has a higher coupling coefficient than the related art, and can be simultaneously perpendicular to each other. A wider offset tolerance range is provided in three directions, such as the horizontal direction and the rotation of the central axis of the mechanism, which provides a more diverse selection of magnetic circuit coupling mechanisms for the selection of the magnetic circuit coupling mechanism of the wireless energy transmission system.

The cross-type magnetic circuit coupling mechanism described above is only an original model for convenience of explanation, and is not an optimized result. The following uses the control variable method to further optimize the cross-type magnetic circuit coupling mechanism in combination with the parameters shown in FIG.

Firstly, the ferrite core layer of the cross-type magnetic circuit coupling mechanism is optimized. Figure 7 (a), (b), (c), (d), (e) are ferrite magnets of five different schemes. The core layer, in the case of replacing only the ferrite core layer and other conditions are the same, the coupling coefficient and ferrite volume comparison results are shown in Table 1:

Table 1

It can be seen from Table 1. As the breath distance increases, the coupling coefficient will become smaller and smaller, but the more ferrite materials are used, the better the effect. The ferrite in Figure 7(a)-(e) The amount of bulk material used is decreasing in turn. The ferrite material used in the ferrite core layer in scheme (e) is at least 2592cm ³ , which is only 9/25 of the scheme (a) with the most ferrite material usage, but except Under the 100mm breath, the coupling coefficient of scheme (e) is slightly smaller than that of scheme (a), and the coupling coefficient of scheme (e) is higher than other schemes in other cases. In summary, the option (e) is used as the ferrite core layer structure of the cross-type magnetic circuit coupling mechanism of the present invention, and the specific structural parameters under the scheme are optimized below.

The ferrite core layer obtained by the cross-type magnetic circuit coupling mechanism as described above is formed by the average longitudinal and transverse cross-distribution of eight ferrite strips, but this is not the optimal structure. The following is combined with the ferrite defined above. The side length of the core layer and the length a of the rectangular coil, the width b of the rectangular coil, the number of turns of the rectangular coil n, the outer margin of the middle ferrite strip is defined as w, and the ratio of b to a is q, w and a The ratio is c and other parameters to further optimize the structure shown in scheme (e).

Embodiment 2: Through a large number of experiments, it can be known that under the premise of unsaturated, the width and thickness of the ferrite strip reach a certain value and do not have much influence on the coupling coefficient of the cross-type magnetic circuit coupling mechanism, so for the convenience of analysis, This embodiment uses a relatively easily obtained manganese-zinc ferrite strip material having a width of 30 mm and a thickness of 20 mm. The position of the middle two ferrite strips is the key to optimization. The curves shown in Fig. 8 to Fig. 9 are the ratio of the coupling coefficient k of the cross-type magnetic circuit coupling mechanism with the ratio of w to a under the condition of 200mm breath distance and n=10匝. The relationship curve for c.

FIG. 8 shows a relationship between k and c only when a is different and q=0.5; and FIG. 9 is a relationship between k and c only when q is different and a=600 mm. It can be seen from Figures 8 and 9 that under different conditions of a and q, the coupling coefficient k of the cross-type magnetic circuit coupling mechanism obtains the maximum value (Max) at c=0.2, so that the optimal ferrite core can be obtained. The layer structure is as shown in Fig. 10, that is, the optimum structure is obtained when the outer margins of the two ferrite strips are w=0.2a.

The shape of the cross-type magnetic circuit coupling mechanism is further optimized under the premise of using the optimized ferrite core layer structure as shown in FIG. 10, mainly for the side length of the ferrite core layer and the length of the rectangular coil. a, the width b of the rectangular coil is optimized. For the convenience of analysis, assuming that n=10匝 and the breath distance is 200mm, the relationship between the coupling coefficient k and q when a takes different values is shown in Fig. 11. As can be seen from the graph in Fig. 11, the larger the a value is, the higher the coupling coefficient k is, and the coupling coefficient k always takes the maximum value at q = 0.7 regardless of the value of a. Fig. 12 is a graph showing the relationship between the coupling coefficient k and q when the air gap is different at n=10匝 and a=600mm. It can be seen from the figure that the smaller the breath distance is, the higher the coupling coefficient k is. Similarly, regardless of the breath distance, the coupling coefficient k always takes the maximum value at q=0.7. In summary, the ratio q of the width b of the rectangular coil to the length a has an optimal solution, that is, under the same condition, the coupling coefficient k of the cross-type magnetic circuit coupling mechanism is the largest when q=0.7.

In order to analyze a certain characteristic parameter to the cross-type magnetic circuit coupling mechanism, many optimization analysis in the previous article is based on the condition that the number of rectangular coil turns is 10匝, although this method is beneficial to optimize the analysis process, but its special analysis process It will also make its conclusions non-universal. In order to make the optimization results more general, now change the rectangular coil turns n to verify whether the previous optimization analysis results are still valid.

Figure 13 shows 30 variations of q from 0.01 to 1 in increments of 0.01 and a number of turns of rectangular coils from 10 to 30 in steps of 10 with a = 600 mm and Air gap = 200 mm. The k-c curve of the case can be obtained from the figure. The 30 curves simultaneously obtain the maximum (Max) point at c=0.2, so the optimal structure and rectangular coil of the ferrite core layer shown in Fig. 10 can be verified. The number of turns is independent of the ratio q, which has general applicability in a cross-type magnetic circuit coupling mechanism. Figure 13 is a diagram showing the optimum ferrite core structure shown in Figure 15 and under the premise of a = 600 mm and Air gap = 200 mm, the number of rectangular turns n is 10 匝, 20 匝, 30 分别, respectively. With the curve of q, it can be seen from the figure that the three curves simultaneously obtain the maximum point at q=0.7, so the ratio q of the width b of the optimal rectangular coil to the length a is 0.7, which is independent of the number of turns of the rectangular coil, and is common. Sex.

As can be seen from the above, the schematic diagram of the optimized structure of the primary side energy emitting pad or the secondary side energy picking pad of the cross type magnetic circuit coupling mechanism is shown in FIG. 15, and FIG. 15 is a structural view of Embodiment 3, wherein q=0.7, w= 0.2a.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " After, "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship of the "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is merely for convenience of description of the present invention and simplified description, and does not indicate or imply the indicated device or component. It must be constructed and operated in a particular orientation, and is not to be construed as limiting the invention.

Moreover, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" or "second" may include at least one of the features, either explicitly or implicitly. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless specifically defined otherwise.

In the present invention, the terms "installation", "connected", "connected", "fixed" and the like shall be understood broadly, and may be either a fixed connection or a detachable connection, unless explicitly stated and defined otherwise. , or integrated; can be mechanical or electrical connection; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction of two elements, unless otherwise specified Limited. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

In the present invention, the first feature "on" or "under" the second feature may be a direct contact of the first and second features, or the first and second features may be indirectly through an intermediate medium, unless otherwise explicitly stated and defined. contact. And, the first A feature "above", "above" and "above" the second feature may be that the first feature is directly above or above the second feature, or merely that the first feature level is higher than the second feature. The first feature "below", "below" and "below" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely that the first feature level is less than the second feature.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means a specific feature described in connection with the embodiment or example. A structure, material or feature is included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, may be combined and combined.

The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

A novel radio energy transmission magnetic circuit coupling mechanism, comprising: a primary side energy emitting pad and a secondary side energy picking pad, the primary side energy emitting pad and the secondary side energy picking pad are oppositely arranged and parallel to each other; primary side energy emission The pad and the secondary energy pick-up pad are of a two-layer structure, one of which is a coil layer wound by a Litz wire, and the other layer is a core layer; the coil layer and the core layer are both centrally symmetric; The coil layer is composed of two identical rectangular coils stacked orthogonally, and the core layer is a nine-grid grid layer composed of eight ferrite strips of equal length; the primary side energy emitting pad and the secondary side energy picking pad The coil layers are opposite, and the opposite sides of the primary side energy emitting pad and the secondary side energy picking pad are mirror symmetrical with each other.
A novel wireless power transmission magnetic circuit coupling mechanism according to claim 1, wherein the length of the ferrite strip is equal to the length of the rectangular coil.
A novel radio energy transmission magnetic circuit coupling mechanism according to claim 2, wherein among the four ferrite strips in the middle of the magnetic core layer, the positions of any two parallel ferrite strips are satisfied. The following conditions:

w=0.2a

Where w represents the outer margin of two mutually parallel ferrite bars; a represents the length of the rectangular coil.
A novel radio energy transmission magnetic circuit coupling mechanism according to claim 3, wherein the ratio of the width to the length of said rectangular coil is 0.7.