CA3031438A1 - New wireless electric energy transmission magnetic path coupling mechanism - Google Patents
New wireless electric energy transmission magnetic path coupling mechanism Download PDFInfo
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/2871—Pancake coils
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/14—Inductive couplings
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F17/00—Fixed inductances of the signal type
- H01F17/0006—Printed inductances
- H01F2017/0066—Printed inductances with a magnetic layer
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/2804—Printed windings
- H01F2027/2809—Printed windings on stacked layers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/14—Inductive couplings
- H01F2038/143—Inductive couplings for signals
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
Description New Wireless Electric Energy Transmission Magnetic Path Coupling Mechanism I. Technical Field The present invention relates to the technical field of wireless electric energy transmission, particularly to a new magnetic path coupling mechanism for wireless electric energy transmission.
Background Art Wireless electric energy transmission technology is a fire-new electric power access mode that realizes the transmission of electric power from a power source device to a power-receiving device under a condition of complete electrical isolation by means of a spatial invisible soft medium (e.g., magnetic field, electric field, laser, microwave, etc.).
The technology fundamentally eliminates the problems of device wear, poor contact and touch spark, etc. caused by the conventional "socket + connector" power supply mode, and is a clean, safe and flexible new power supply mode. It has been evaluated by Technology Review in USA as one of the ten major scientific research directions in the future.
Wherein, a magnetic path coupling mechanism for wireless electric energy transmission is a key essential difference between the wireless electric energy transmission technology and the conventional wire electric energy transmission mode, and the performance thereof characterizes the quality of the wireless electric energy transmission system.
Therefore, it is very important to make research on the magnetic path coupling mechanism for wireless electric energy transmission. The key index for measuring the performance of the magnetic path coupling mechanism for wireless electric energy transmission is the coupling coefficient k, which can measure the coupling degree of the magnetic path mechanism. In practice, the coupling coefficient k is usually in the range of 0.01 to 0.5. The higher the k value is, the closer the coupling of the magnetic path mechanism is, and the higher the efficiency of the magnetic path coupling mechanism is.
Owing to a fact that there is a large air gap between the primary side energy emission cushion and the secondary side energy collection cushion of the magnetic path coupling mechanism for wireless electric energy transmission in order to realize non-contact, it is difficult to align the secondary side energy collection cushion with the primary side energy emission cushion accurately, and relative position offset between the primary side energy emission cushion and the secondary side energy collection cushion is inevitable.
Therefore, a magnetic path coupling mechanism with a wider offset tolerance range is = =
more practical. A variety of possible offset positions may exist between the primary side energy emission cushion and the secondary side energy collection cushion. For the convenience of research, usually three offset directions, i.e., two orthogonal horizontal directions coplanar with the secondary side energy collection cushion and a direction of rotation around the central axis thereof, are selected, in order to study the anti-offset characteristics of the magnetic path coupling mechanism. Any offset condition of the magnetic path coupling mechanism can be achieved by superimposing the above three offset directions. In particular, a greater coupling coefficient k can provide a wider offset tolerance range.
A great many of researches have been made on magnetic path coupling mechanisms for wireless electric energy transmission, and in relevant techniques, a DD-type magnetic path coupling mechanism proposed by the University of Auckland has been applied widely owing to its excellent performance. The DD-type magnetic path coupling mechanism is developed from a magnetron-based magnetic path coupling mechanism.
However, compared with the latter, the former only provides a flux path on one side in the air, while the flux path on the other side forms a closed path via the associated ferrite strip. Therefore, the DD-type magnetic path coupling mechanism has a greater coupling coefficient with the same gap. Besides, the DD-type magnetic path coupling mechanism has a better offset tolerance in the direction perpendicular to the ferrite strip thereof, but has a poorer offset tolerance in the direction parallel to the ferrite strip thereof and the direction of rotation around the center of the mechanism.
III. Contents of the Invention Object of the Invention: the object of the present invention is to provide a new magnetic path coupling mechanism for wireless electric energy transmission, which not only has a higher coupling coefficient, but also provides wider offset tolerance ranges in three directions, i.e., two orthogonal horizontal directions and a direction of rotation around the central axis of the mechanism.
Technical Solution: to attain the above-mentioned technical effects, the present invention provides the following technical solution:
A new magnetic path coupling mechanism for wireless electric energy transmission, comprising: a primary side energy emission cushion and a secondary side energy collection cushion, which are arranged opposite to each other and in parallel with each other; both the primary side energy emission cushion and the secondary side energy collection cushion are of a two-layer structure, wherein, one layer is a coil layer formed by winding Litz wires, and the other layer is a magnetic core layer; both the coil layer and the magnetic core layer are of a centrosymmetric structure; wherein, the coil layer consists of two identical rectangular coils laminated orthogonally, and the magnetic core = 2 =
layer is a Sudoku-shaped grid layer consisting of 8 ferrite strips with the same length; the coil layer of the primary side energy emission cushion and the coil layer of the secondary side energy collection cushion are opposite to each other, and the opposite surfaces of the primary side energy emission cushion and the secondary side energy collection cushion are in mirror symmetry.
Furthermore, the length of the ferrite strip is equal to the length of the rectangular coil.
Furthermore, among the 4 ferrite strips in the middle of the magnetic core layer, the positions of any two ferrite strips parallel to each other meet the following condition:
w=0 .2a wherein, w is the outer margin between two ferrite strips parallel to each other; a is the length of the rectangular coil.
Furthermore, the ratio of the width to the length of the rectangular coil is 0.7.
Benefits: compared with the prior art, the present invention has the following advantages:
The new magnetic path coupling mechanism for wireless electric energy transmission according to the present invention is a magnetic path coupling structure with outstanding performance. Compared with relevant techniques, the new magnetic path coupling mechanism for wireless electric energy transmission according to the present invention has a higher coupling coefficient, and can provide wider offset tolerance ranges in three directions at the same time, i.e., two orthogonal horizontal directions and a direction of rotation around the central axis of the mechanism. The present invention provides a more diversified option of magnetic path coupling mechanism for selection of magnetic path coupling mechanism for wireless electric energy transmission system.
IV. Brief Description of Drawings Fig. 1 is a schematic structural view of example 1;
Fig. 2 is a schematic view of the winding pattern and key parameters of the primary side energy emission cushion according to example 1;
Fig. 3 shows the Model diagram of magnetic path coupling mechanism in the prior art;
Fig. 4 shows the comparison diagram of the air gap tolerance characteristic between a DD-type magnetic path coupling mechanism and the cross-type magnetic path coupling mechanism according to example 1 under the same conditions;
Fig. 5 shows the comparison diagram of the central rotation angle tolerance characteristic between a DD-type magnetic path coupling mechanism and the cross-type magnetic path coupling mechanism according to example 1 under the same conditions;
= 3 =
Fig. 6 shows the comparison diagram of the horizontal offset tolerance characteristic between a DD-type magnetic path coupling mechanism and the cross-type magnetic path coupling mechanism according to example 1 under the same conditions;
Fig. 7 shows schematic structural views of ferrite core layer of the cross-type magnetic path coupling mechanism according to example 1 in five different schemes;
Fig. 8 shows the comparison diagram of relation curves between coupling coefficient k and c of the cross-type magnetic path coupling mechanism according to example 1 for different values of a and q=0.5, under the conditions of air gap=200 mm, n=10 turns;
Fig. 9 shows the comparison diagram of relation curves between coupling coefficient k and c of the cross-type magnetic path coupling mechanism according to example 1 for different values of q and a=600 mm, under the conditions of air gap=200 mm, n=10 turns;
Fig. 10 is a schematic diagram illustrating the ferrite magnetic core layer structure and parameters according to example 2;
Fig. 11 shows the diagram of relation curves of coupling coefficient k and q of the cross-type magnetic path coupling mechanism according to example 2 for different values of a, under the conditions of n=10 turns and air gap=200mm;
Fig. 12 shows the diagram of relation curves of coupling coefficient k and q of the cross-type magnetic path coupling mechanism according to example 2 for different values of air gap, under the conditions of n=10 turns and a=600mm;
Fig. 13 shows the diagram of curves of k vs. c of the cross-type magnetic path coupling mechanism according to example 2 in 30 cases when the value of q is changed from 0.5 to 1 in step of 0.01 and the number of turns of the rectangular coils is changed from 10 turns to 30 turns in step of 10 under the conditions of a=600 mm and air gap=200 mm;
Fig. 14 shows the diagram of curves of k vs. q when the optimal ferrite magnetic core layer structure shown in Fig. 16 is used in three cases where the number of turns n of the rectangular coil is 10, 20 and 30 respectively under the conditions of a=600 and air gap=200 mm;
Fig. 15 is a structural diagram of example 3.
In the figures: 101 - first coil layer; 102 - first magnetic core layer; 201 -second coil layer; 203 - second magnetic core layer.
V. Embodiments Hereunder the present invention will be further detailed with reference to the = 4 =
accompanying drawings.
Example 1: Fig. 1 is a structural diagram of example 1 of the present invention. As shown in Fig. 1, the magnetic path coupling mechanism for wireless electric energy transmission comprises: a primary side energy emission cushion and a secondary side energy collection cushion; wherein, the primary side energy emission cushion comprises a first coil layer 101 and a first magnetic core layer 102, wherein the first coil layer 101 is disposed above the first magnetic core layer 102; the secondary side energy collection cushion comprises a second coil layer 201 and a second magnetic core layer 202, wherein the second coil layer 202 is disposed below the second magnetic core layer 202.
Both the first coil 101 and the second coil 201 consist of two identical rectangular coils laminated orthogonally. Both of the rectangular coils are wound from Litz wires.
Both the first magnetic core layer 102 and the second magnetic core layer 202 consist of 8 ferrite strips intersecting each other in longitudinal and transverse directions, and the first magnetic core layer 102 and the second magnetic core layer 202 are entirely centrally symmetric.
The outer edge length of the first/second magnetic core layers 102/202 is equal to the length of the first/second coils 101/201.
In the new magnetic path coupling mechanism for wireless electric energy transmission according to the example 1, the primary side energy emission cushion has the same structure and the same winding pattern with the secondary side energy collection cushion.
For example, the winding pattern and key parameters of the primary side energy emission cushion are shown in Fig. 2: it consists of a first coil 101 and a first magnetic core layer 102, and the overall structure is in central symmetry. The first coil 101 consists of two identical rectangular coils laminated orthogonally. Therefore, the magnetic path coupling mechanism according to the present invention is also referred to as a cross-type magnetic path coupling mechanism, and the winding pattern thereof is indicated by the arrows in Fig. 2. For the convenience of further describing an optimal composition of the magnetic path coupling mechanism, the side length of the ferrite magnetic core layer and the length of the rectangular coils are defined as a, the width of the rectangular coils is defined as b, the number of turns is defined as n, the ferrite strips of the magnetic core layer are Mg-Zn ferrite strips with 30 mm width and 20 mm thickness, the outer margin of the middle ferrite strips is defined as w, the ratio of b to a is defined as q, and the ratio of w to a is defined as c.
Fig. 3 shows a common magnetic path coupling mechanism with good performance in the prior art, which is usually referred to as a DD-type magnetic path coupling mechanism. To compare the performance of the cross-type magnetic path coupling = 5 =
mechanism according to the example 1 with the performance of the DD-type magnetic path coupling mechanism, the cross-type magnetic path coupling mechanism with the same dimensions (600* 600 mm), the same Litz wire length (65.6m) and the same number of turns of rectangular coils (10 turns) as the DD-type magnetic path coupling mechanism shown in Fig. 3 is manufactured, as shown in Fig. 1. In Fig. 3, the DD-type magnetic path coupling mechanism uses a ferrite material in volume of 5,760cm3, and has a coupling coefficient of 0.21 with 200 mm air gap; in contrast, the cross-type magnetic path coupling mechanism only uses a ferrite material in volume of 5,184cm3 but has a coupling coefficient as high as 0.2439 with 200 mm air gap.
Figs. 4-6 show further comparison of offset tolerance between the cross-type magnetic path coupling mechanism and the DD-type magnetic path coupling mechanism under the above-mentioned conditions, wherein, Figs. 4, 5 and 6 respectively show comparison diagrams of coupling coefficient vs. air gap, central rotation angle and horizontal offset between the two magnetic path coupling mechanisms.
The curve (1) and curve (2) in Fig. 4 are relation curves of coupling coefficient k vs. air gap of the cross-type magnetic path coupling mechanism and the DD-type magnetic path coupling mechanism respectively. It can be seen clearly that the cross-type magnetic path coupling mechanism is more advantageous than the DD-type magnetic path coupling mechanism within an air gap range of 100-250 mm.
The curve (3) and curve (4) in Fig. 5 are relation curves of coupling coefficient k vs.
central rotation angle of the cross-type magnetic path coupling mechanism and the DD-type magnetic path coupling mechanism with air gap of 200 mm. It can be seen from the figure: the coupling coefficient k of the DD-type magnetic path coupling mechanism fluctuates severely as the central rotation angle increases; particularly, the value of k is maximum at 00 and 180 angles, but is close to 0 at 90 and 270 angles, which brings severe disturbances to stable operation of the entire wireless electric energy transmission system. In contrast, the coupling coefficient of the cross-type magnetic path coupling mechanism essentially remains unchanged and the stable value thereof is greater than the coupling coefficient of the DD-type magnetic path coupling mechanism when a central rotation offset occurs.
The curve (5) in Fig. 6 is a coupling coefficient curve of the cross-type magnetic path coupling mechanism with horizontal offset in the cross or y direction. Since the cross-type magnetic path coupling mechanism is in central symmetry, it has the same horizontal offset tolerance characteristic in the cross or y direction, so there is only one curve (5) in Fig. 6. In contrast, for the DD-type magnetic path coupling mechanism, since the horizontal offset tolerance characteristics in the cross direction and y direction are different from each other, the horizontal offset tolerance characteristics are illustrate by = 6 =
curves (6) and (7) respectively. It can be seen from the figure: the offset tolerance characteristic of the DD-type magnetic path coupling mechanism in the cross direction is poorer than the offset tolerance characteristic in the y direction; moreover, a blind spot (spot with k=0) occurs at 220 mm offset in the cross direction. The horizontal offset tolerance characteristic of the cross-type magnetic path coupling mechanism in the cross or y direction is superior to the offset tolerance characteristic of the DD-type magnetic path coupling mechanism in the cross direction; the coupling coefficient of the cross-type magnetic path coupling mechanism is greater than that of the DD-type magnetic path coupling mechanism in case that the offset in the y direction is 0-135 mm; the coupling coefficient of the DD-type magnetic path coupling mechanism is greater than that of the cross-type magnetic path coupling mechanism in case that the offset in the y direction is greater than 135 mm.
In summary, the cross-type magnetic path coupling mechanism according to the present invention is a magnetic path coupling structure with outstanding performance.
Compared with relevant techniques in the prior art, it has a higher coupling coefficient, and can provide wider offset tolerance ranges in three directions at the same time, i.e., two orthogonal horizontal directions and a direction of rotation around the central axis of the mechanism. Thus, it provides an option of more diversified magnetic path coupling mechanism for selection of magnetic path coupling mechanism for wireless electric energy transmission system.
The cross-type magnetic path coupling mechanism described above is only an original model for illustration purpose rather than an optimal result. Hereunder the cross-type magnetic path coupling mechanism will be further optimized and analyzed with a control variable method, utilizing the parameters shown in Fig. 2.
First, optimization design is carried out for the ferrite magnetic core layer of the cross-type magnetic path coupling mechanism. Figs. 7(a), 7(b), 7(c), 7(d) and 7(e) show five different schemes of ferrite magnetic core layer. The result of comparison of coupling coefficient and ferrite volumes achieved by replacing the ferrite magnetic core layer only while keeping other conditions unchanged is shown in Table 1:
Table 1 Shape (a) (b) (c) (d) (e) 0.485 (100 mm) 0.445 (100 mm) 0.457 (100 mm) 0.472 (100 mm) 0.483 (100 mm) Coupling 0.338 (150 mm) 0.308 (150 mm) 0.317 (150 mm) 0.331 (150 mm) 0.342 (150 mm) coefficient k (air gap) 0.239 (200 mm) 0.215 (200 mm) 0.224 (200 mm) 0.235 (200 mm) 0.244 (200 mm) 0.172 (250 mm) 0.156 (250 mm) 0.161 (250 mm) 0.170 (250 mm) 0.177 (250 mm) Ferrite 7200 cm3 5400 cm3 3384 cm3 3150 cm3 2592cm3 = 7 =
volume It can be seen from Table 1: as the air gap is increased, the coupling coefficient becomes smaller; however, the use of more ferrite material does not always result in better effect.
In Figs. 7(a)-(e), the amounts of ferrite materials are decreased sequentially, and the amount of ferrite material in the ferrite magnetic core layer in the scheme (e) is the lowest (2,592 cm3), and is only 9/25 of the highest amount of ferrite material used in the scheme (a); however, the coupling coefficient in the scheme (e) is only slightly lower than the coupling coefficient in the scheme (a) when the air gap is 100 mm, but is higher than the coupling coefficients in all other schemes in other cases. In summary, the scheme (e) is selected for the ferrite magnetic core layer structure of the cross-type magnetic path coupling mechanism according to the present invention. Hereunder the specific structural parameters of that scheme will be optimized.
The ferrite magnetic core layer in the cross-type magnetic path coupling mechanism described above consists of 8 ferrite strips that intersect each other in longitudinal and transverse direction to form a grid, but it is not an optimal structure.
Hereunder the structure in the scheme (e) will be further optimized, with the parameters defined above, including the side length of the ferrite magnetic core layer and length a of the rectangular coils, width b of the rectangular coils, number of turns n of the rectangular coils, outer margin w of the middle ferrite strips, ratio q of b to a, and ratio c of w to a, etc.
Example 2: through a lot of experiments, it can be known that in an under-saturated state, further increasing the width and thickness of the ferrite strips has little contribution to the coupling coefficient of the cross-type magnetic path coupling mechanism after the width and thickness of the ferrite strips reach certain values. Therefore, for the convenience of analysis, Mg-Zn ferrite strips with 30 mm width and 20 mm thickness, which can be obtained easily, are used in this example. The positions of the two middle ferrite strips are the key to the optimization. The curves shown in Figs. 8-9 are relation curves of coupling coefficient k vs. the ratio c of w to a of a cross-type magnetic path coupling mechanism under the conditions of air gap=200 mm and n=10 turns.
Wherein, Fig. 8 shows relation curves of k vs. c for different values of a with q=0.5; Fig.
9 shows relation curves of k vs. c for different values of q with a=600 mm. It can be seen from Figs. 8 and 9: for different values of a and different values of q, the coupling coefficient k of the cross-type magnetic path coupling mechanism reaches its maximum value (Max) at c=0.2. Thus, an optimal ferrite magnetic core layer structure is obtained, as shown in Fig. 10, i.e., the structure is optimal when the outer margin w of the two middle ferrite strips is equal to 0.2a.
Hereunder the shape of the cross-type magnetic path coupling mechanism will be further = 8 =
optimized under the premise that the optimized ferrite magnetic core layer structure shown in Fig. 10 is used. Mainly the side length of the ferrite magnetic core layer, the length a of the rectangular coils, and the width b of the rectangular coils will be optimized. For the convenience of analysis, assuming n=10 turns and air gap=200 mm, the relation curves of coupling coefficient k vs. q for different values of a are shown in Fig. 11. It can be seen from the curves in Fig. 11: the higher the value of a is, the higher the coupling coefficient k is; in addition, the coupling coefficient k reaches its maximum value at q=0.7, regardless of the value of a. Fig. 12 shows relation curves of coupling coefficient k vs. q for different values of air gap under the conditions of n=10 turns and a=600 mm. It can be seen from the figure: the smaller the air gap is, the higher the coupling coefficient k is; likewise, the coupling coefficient k always reaches its maximum value at q=0.7, regardless of the value of air gap. In summary, there is an optimal solution to the ratio q of width b to length a of the rectangular coils; namely, under the same condition, the coupling coefficient k of the cross-type magnetic path coupling mechanism is maximum when q=0.7.
The optimization and analysis described above are based on a condition that the number of turns of the rectangular coils is 10 turns, for the purpose of analyzing the influence of a specific characteristic parameter on the cross-type magnetic path coupling mechanism.
Though such a method is beneficial for the optimization and analysis process, the conclusion may not be universal owing to the particularity of the analysis process. To improve the universality of the optimization result, whether the result of optimization and analysis described above is still true will be verified by changing the condition of the number of turns n of the rectangular coils.
Fig. 13 shows the curves of k vs. c in 30 cases formed when q is changed from 0.5 to 1 in step of 0.01 and the number of turns of the rectangular coils is changed from 10 to 30 in step of 10 on the premise of a=600 mm and air gap=200 mm. It can be seen from the figure: all of the 30 curves simultaneously obtain the maximum value (Max) at c=0.2.
Thus, it is verified that the optimal ferrite magnetic core layer structure shown in Fig. 10 is independent of the number of turns of the rectangular coils and the ratio q, and is universally applicable to cross-type magnetic path coupling mechanisms. Fig.
13 shows curves of k vs. q in three cases (the number of turns n of the rectangular coils is 10, 20, and 30 respectively) with the optimal ferrite magnetic core layer structure shown in Fig.
15 on a premise of a=600 mm and air gap=200 mm. It can be seen from the figure: all of the three curves simultaneously obtain the maximum value at q=0.7. Therefore, the optimal ratio q of width b to length a of the rectangular coils is 0.7, and it is independent of the number of turns n of the rectangular coils and has universality.
Based on the above description, a schematic diagram of the optimal structure of the primary side energy emission cushion or secondary side energy collection cushion of the = 9 =
cross-type magnetic path coupling mechanism is shown in Fig. 15, which is a structural diagram of the example 3, wherein, q=0.7 and w=0.2a.
In the description of the present invention, it should be understood that the orientation or position relations indicated by terms "center", "longitudinal", "transverse", "length", "width", "thickness", "above", "below", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counter-clockwise", "axial", "radial", or "circumferential", etc., are based on the orientation or position relations indicated in the drawings. They are used only to describe the present invention and simplify the description, rather than indicate or imply that the involved device or element must have a specific orientation or must be constructed and operated in a specific orientation. Therefore, the use of these terms shall not be deemed as a limitation to the present invention.
In addition, the terms "first" and "second" are used only for description purpose, and shall not be interpreted as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Hence, the feature limited by "first" or "second" may explicitly or implicitly comprise at least one such feature. In the description of the present invention, "a plurality of' or "multiple" means at least two, such as two or three, etc., unless otherwise defined explicitly.
In the present invention, unless otherwise specified and defined explicitly, the terms "install", "connect", "fix", etc. shall be interpreted in their general meaning. For example, the connection may be fixed connection, detachable connection, or integral connection;
may be mechanical connection or electrical connection; may be direct connection or indirect connection via an intermediate medium, or internal communication or interactive relation between two elements, unless otherwise defined explicitly. The person skilled in the art may interpret the specific meanings of the terms in the context of the present invention.
In the present invention, unless otherwise specified and defined explicitly, a first feature being "above" or "below" a second feature may represent that the first feature and the second feature directly contact with each other or the first feature and the second feature contact with each other indirectly via an intermediate medium. In addition, a first feature being "over" a second feature may represent that the first feature is right over or diagonally over the second feature, or may only represent that the elevation of the first feature is higher than that of the second feature. A first feature being "under" a second feature may represent that the first feature is right under or diagonally under the second feature, or may only represent that the elevation of the first feature is lower than that of the second feature.
In the description of the present invention, the expressions of reference terms "an = 10 =
embodiment", "some embodiments", "an example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in these embodiments or examples are included in at least one embodiment or example of the present invention. In the description of the present application, the exemplary expression of the above terms may not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined appropriately in one or more embodiments or examples. Furthermore, in case of without mutual contradiction, the person skilled in the art may combine or assemble different embodiments or examples and features in different embodiments or examples described herein.
While the present invention is described above in some preferred embodiments, it should be noted that the person skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should be deemed as falling into the scope of protection of the present invention.
= 11 =
Background Art Wireless electric energy transmission technology is a fire-new electric power access mode that realizes the transmission of electric power from a power source device to a power-receiving device under a condition of complete electrical isolation by means of a spatial invisible soft medium (e.g., magnetic field, electric field, laser, microwave, etc.).
The technology fundamentally eliminates the problems of device wear, poor contact and touch spark, etc. caused by the conventional "socket + connector" power supply mode, and is a clean, safe and flexible new power supply mode. It has been evaluated by Technology Review in USA as one of the ten major scientific research directions in the future.
Wherein, a magnetic path coupling mechanism for wireless electric energy transmission is a key essential difference between the wireless electric energy transmission technology and the conventional wire electric energy transmission mode, and the performance thereof characterizes the quality of the wireless electric energy transmission system.
Therefore, it is very important to make research on the magnetic path coupling mechanism for wireless electric energy transmission. The key index for measuring the performance of the magnetic path coupling mechanism for wireless electric energy transmission is the coupling coefficient k, which can measure the coupling degree of the magnetic path mechanism. In practice, the coupling coefficient k is usually in the range of 0.01 to 0.5. The higher the k value is, the closer the coupling of the magnetic path mechanism is, and the higher the efficiency of the magnetic path coupling mechanism is.
Owing to a fact that there is a large air gap between the primary side energy emission cushion and the secondary side energy collection cushion of the magnetic path coupling mechanism for wireless electric energy transmission in order to realize non-contact, it is difficult to align the secondary side energy collection cushion with the primary side energy emission cushion accurately, and relative position offset between the primary side energy emission cushion and the secondary side energy collection cushion is inevitable.
Therefore, a magnetic path coupling mechanism with a wider offset tolerance range is = =
more practical. A variety of possible offset positions may exist between the primary side energy emission cushion and the secondary side energy collection cushion. For the convenience of research, usually three offset directions, i.e., two orthogonal horizontal directions coplanar with the secondary side energy collection cushion and a direction of rotation around the central axis thereof, are selected, in order to study the anti-offset characteristics of the magnetic path coupling mechanism. Any offset condition of the magnetic path coupling mechanism can be achieved by superimposing the above three offset directions. In particular, a greater coupling coefficient k can provide a wider offset tolerance range.
A great many of researches have been made on magnetic path coupling mechanisms for wireless electric energy transmission, and in relevant techniques, a DD-type magnetic path coupling mechanism proposed by the University of Auckland has been applied widely owing to its excellent performance. The DD-type magnetic path coupling mechanism is developed from a magnetron-based magnetic path coupling mechanism.
However, compared with the latter, the former only provides a flux path on one side in the air, while the flux path on the other side forms a closed path via the associated ferrite strip. Therefore, the DD-type magnetic path coupling mechanism has a greater coupling coefficient with the same gap. Besides, the DD-type magnetic path coupling mechanism has a better offset tolerance in the direction perpendicular to the ferrite strip thereof, but has a poorer offset tolerance in the direction parallel to the ferrite strip thereof and the direction of rotation around the center of the mechanism.
III. Contents of the Invention Object of the Invention: the object of the present invention is to provide a new magnetic path coupling mechanism for wireless electric energy transmission, which not only has a higher coupling coefficient, but also provides wider offset tolerance ranges in three directions, i.e., two orthogonal horizontal directions and a direction of rotation around the central axis of the mechanism.
Technical Solution: to attain the above-mentioned technical effects, the present invention provides the following technical solution:
A new magnetic path coupling mechanism for wireless electric energy transmission, comprising: a primary side energy emission cushion and a secondary side energy collection cushion, which are arranged opposite to each other and in parallel with each other; both the primary side energy emission cushion and the secondary side energy collection cushion are of a two-layer structure, wherein, one layer is a coil layer formed by winding Litz wires, and the other layer is a magnetic core layer; both the coil layer and the magnetic core layer are of a centrosymmetric structure; wherein, the coil layer consists of two identical rectangular coils laminated orthogonally, and the magnetic core = 2 =
layer is a Sudoku-shaped grid layer consisting of 8 ferrite strips with the same length; the coil layer of the primary side energy emission cushion and the coil layer of the secondary side energy collection cushion are opposite to each other, and the opposite surfaces of the primary side energy emission cushion and the secondary side energy collection cushion are in mirror symmetry.
Furthermore, the length of the ferrite strip is equal to the length of the rectangular coil.
Furthermore, among the 4 ferrite strips in the middle of the magnetic core layer, the positions of any two ferrite strips parallel to each other meet the following condition:
w=0 .2a wherein, w is the outer margin between two ferrite strips parallel to each other; a is the length of the rectangular coil.
Furthermore, the ratio of the width to the length of the rectangular coil is 0.7.
Benefits: compared with the prior art, the present invention has the following advantages:
The new magnetic path coupling mechanism for wireless electric energy transmission according to the present invention is a magnetic path coupling structure with outstanding performance. Compared with relevant techniques, the new magnetic path coupling mechanism for wireless electric energy transmission according to the present invention has a higher coupling coefficient, and can provide wider offset tolerance ranges in three directions at the same time, i.e., two orthogonal horizontal directions and a direction of rotation around the central axis of the mechanism. The present invention provides a more diversified option of magnetic path coupling mechanism for selection of magnetic path coupling mechanism for wireless electric energy transmission system.
IV. Brief Description of Drawings Fig. 1 is a schematic structural view of example 1;
Fig. 2 is a schematic view of the winding pattern and key parameters of the primary side energy emission cushion according to example 1;
Fig. 3 shows the Model diagram of magnetic path coupling mechanism in the prior art;
Fig. 4 shows the comparison diagram of the air gap tolerance characteristic between a DD-type magnetic path coupling mechanism and the cross-type magnetic path coupling mechanism according to example 1 under the same conditions;
Fig. 5 shows the comparison diagram of the central rotation angle tolerance characteristic between a DD-type magnetic path coupling mechanism and the cross-type magnetic path coupling mechanism according to example 1 under the same conditions;
= 3 =
Fig. 6 shows the comparison diagram of the horizontal offset tolerance characteristic between a DD-type magnetic path coupling mechanism and the cross-type magnetic path coupling mechanism according to example 1 under the same conditions;
Fig. 7 shows schematic structural views of ferrite core layer of the cross-type magnetic path coupling mechanism according to example 1 in five different schemes;
Fig. 8 shows the comparison diagram of relation curves between coupling coefficient k and c of the cross-type magnetic path coupling mechanism according to example 1 for different values of a and q=0.5, under the conditions of air gap=200 mm, n=10 turns;
Fig. 9 shows the comparison diagram of relation curves between coupling coefficient k and c of the cross-type magnetic path coupling mechanism according to example 1 for different values of q and a=600 mm, under the conditions of air gap=200 mm, n=10 turns;
Fig. 10 is a schematic diagram illustrating the ferrite magnetic core layer structure and parameters according to example 2;
Fig. 11 shows the diagram of relation curves of coupling coefficient k and q of the cross-type magnetic path coupling mechanism according to example 2 for different values of a, under the conditions of n=10 turns and air gap=200mm;
Fig. 12 shows the diagram of relation curves of coupling coefficient k and q of the cross-type magnetic path coupling mechanism according to example 2 for different values of air gap, under the conditions of n=10 turns and a=600mm;
Fig. 13 shows the diagram of curves of k vs. c of the cross-type magnetic path coupling mechanism according to example 2 in 30 cases when the value of q is changed from 0.5 to 1 in step of 0.01 and the number of turns of the rectangular coils is changed from 10 turns to 30 turns in step of 10 under the conditions of a=600 mm and air gap=200 mm;
Fig. 14 shows the diagram of curves of k vs. q when the optimal ferrite magnetic core layer structure shown in Fig. 16 is used in three cases where the number of turns n of the rectangular coil is 10, 20 and 30 respectively under the conditions of a=600 and air gap=200 mm;
Fig. 15 is a structural diagram of example 3.
In the figures: 101 - first coil layer; 102 - first magnetic core layer; 201 -second coil layer; 203 - second magnetic core layer.
V. Embodiments Hereunder the present invention will be further detailed with reference to the = 4 =
accompanying drawings.
Example 1: Fig. 1 is a structural diagram of example 1 of the present invention. As shown in Fig. 1, the magnetic path coupling mechanism for wireless electric energy transmission comprises: a primary side energy emission cushion and a secondary side energy collection cushion; wherein, the primary side energy emission cushion comprises a first coil layer 101 and a first magnetic core layer 102, wherein the first coil layer 101 is disposed above the first magnetic core layer 102; the secondary side energy collection cushion comprises a second coil layer 201 and a second magnetic core layer 202, wherein the second coil layer 202 is disposed below the second magnetic core layer 202.
Both the first coil 101 and the second coil 201 consist of two identical rectangular coils laminated orthogonally. Both of the rectangular coils are wound from Litz wires.
Both the first magnetic core layer 102 and the second magnetic core layer 202 consist of 8 ferrite strips intersecting each other in longitudinal and transverse directions, and the first magnetic core layer 102 and the second magnetic core layer 202 are entirely centrally symmetric.
The outer edge length of the first/second magnetic core layers 102/202 is equal to the length of the first/second coils 101/201.
In the new magnetic path coupling mechanism for wireless electric energy transmission according to the example 1, the primary side energy emission cushion has the same structure and the same winding pattern with the secondary side energy collection cushion.
For example, the winding pattern and key parameters of the primary side energy emission cushion are shown in Fig. 2: it consists of a first coil 101 and a first magnetic core layer 102, and the overall structure is in central symmetry. The first coil 101 consists of two identical rectangular coils laminated orthogonally. Therefore, the magnetic path coupling mechanism according to the present invention is also referred to as a cross-type magnetic path coupling mechanism, and the winding pattern thereof is indicated by the arrows in Fig. 2. For the convenience of further describing an optimal composition of the magnetic path coupling mechanism, the side length of the ferrite magnetic core layer and the length of the rectangular coils are defined as a, the width of the rectangular coils is defined as b, the number of turns is defined as n, the ferrite strips of the magnetic core layer are Mg-Zn ferrite strips with 30 mm width and 20 mm thickness, the outer margin of the middle ferrite strips is defined as w, the ratio of b to a is defined as q, and the ratio of w to a is defined as c.
Fig. 3 shows a common magnetic path coupling mechanism with good performance in the prior art, which is usually referred to as a DD-type magnetic path coupling mechanism. To compare the performance of the cross-type magnetic path coupling = 5 =
mechanism according to the example 1 with the performance of the DD-type magnetic path coupling mechanism, the cross-type magnetic path coupling mechanism with the same dimensions (600* 600 mm), the same Litz wire length (65.6m) and the same number of turns of rectangular coils (10 turns) as the DD-type magnetic path coupling mechanism shown in Fig. 3 is manufactured, as shown in Fig. 1. In Fig. 3, the DD-type magnetic path coupling mechanism uses a ferrite material in volume of 5,760cm3, and has a coupling coefficient of 0.21 with 200 mm air gap; in contrast, the cross-type magnetic path coupling mechanism only uses a ferrite material in volume of 5,184cm3 but has a coupling coefficient as high as 0.2439 with 200 mm air gap.
Figs. 4-6 show further comparison of offset tolerance between the cross-type magnetic path coupling mechanism and the DD-type magnetic path coupling mechanism under the above-mentioned conditions, wherein, Figs. 4, 5 and 6 respectively show comparison diagrams of coupling coefficient vs. air gap, central rotation angle and horizontal offset between the two magnetic path coupling mechanisms.
The curve (1) and curve (2) in Fig. 4 are relation curves of coupling coefficient k vs. air gap of the cross-type magnetic path coupling mechanism and the DD-type magnetic path coupling mechanism respectively. It can be seen clearly that the cross-type magnetic path coupling mechanism is more advantageous than the DD-type magnetic path coupling mechanism within an air gap range of 100-250 mm.
The curve (3) and curve (4) in Fig. 5 are relation curves of coupling coefficient k vs.
central rotation angle of the cross-type magnetic path coupling mechanism and the DD-type magnetic path coupling mechanism with air gap of 200 mm. It can be seen from the figure: the coupling coefficient k of the DD-type magnetic path coupling mechanism fluctuates severely as the central rotation angle increases; particularly, the value of k is maximum at 00 and 180 angles, but is close to 0 at 90 and 270 angles, which brings severe disturbances to stable operation of the entire wireless electric energy transmission system. In contrast, the coupling coefficient of the cross-type magnetic path coupling mechanism essentially remains unchanged and the stable value thereof is greater than the coupling coefficient of the DD-type magnetic path coupling mechanism when a central rotation offset occurs.
The curve (5) in Fig. 6 is a coupling coefficient curve of the cross-type magnetic path coupling mechanism with horizontal offset in the cross or y direction. Since the cross-type magnetic path coupling mechanism is in central symmetry, it has the same horizontal offset tolerance characteristic in the cross or y direction, so there is only one curve (5) in Fig. 6. In contrast, for the DD-type magnetic path coupling mechanism, since the horizontal offset tolerance characteristics in the cross direction and y direction are different from each other, the horizontal offset tolerance characteristics are illustrate by = 6 =
curves (6) and (7) respectively. It can be seen from the figure: the offset tolerance characteristic of the DD-type magnetic path coupling mechanism in the cross direction is poorer than the offset tolerance characteristic in the y direction; moreover, a blind spot (spot with k=0) occurs at 220 mm offset in the cross direction. The horizontal offset tolerance characteristic of the cross-type magnetic path coupling mechanism in the cross or y direction is superior to the offset tolerance characteristic of the DD-type magnetic path coupling mechanism in the cross direction; the coupling coefficient of the cross-type magnetic path coupling mechanism is greater than that of the DD-type magnetic path coupling mechanism in case that the offset in the y direction is 0-135 mm; the coupling coefficient of the DD-type magnetic path coupling mechanism is greater than that of the cross-type magnetic path coupling mechanism in case that the offset in the y direction is greater than 135 mm.
In summary, the cross-type magnetic path coupling mechanism according to the present invention is a magnetic path coupling structure with outstanding performance.
Compared with relevant techniques in the prior art, it has a higher coupling coefficient, and can provide wider offset tolerance ranges in three directions at the same time, i.e., two orthogonal horizontal directions and a direction of rotation around the central axis of the mechanism. Thus, it provides an option of more diversified magnetic path coupling mechanism for selection of magnetic path coupling mechanism for wireless electric energy transmission system.
The cross-type magnetic path coupling mechanism described above is only an original model for illustration purpose rather than an optimal result. Hereunder the cross-type magnetic path coupling mechanism will be further optimized and analyzed with a control variable method, utilizing the parameters shown in Fig. 2.
First, optimization design is carried out for the ferrite magnetic core layer of the cross-type magnetic path coupling mechanism. Figs. 7(a), 7(b), 7(c), 7(d) and 7(e) show five different schemes of ferrite magnetic core layer. The result of comparison of coupling coefficient and ferrite volumes achieved by replacing the ferrite magnetic core layer only while keeping other conditions unchanged is shown in Table 1:
Table 1 Shape (a) (b) (c) (d) (e) 0.485 (100 mm) 0.445 (100 mm) 0.457 (100 mm) 0.472 (100 mm) 0.483 (100 mm) Coupling 0.338 (150 mm) 0.308 (150 mm) 0.317 (150 mm) 0.331 (150 mm) 0.342 (150 mm) coefficient k (air gap) 0.239 (200 mm) 0.215 (200 mm) 0.224 (200 mm) 0.235 (200 mm) 0.244 (200 mm) 0.172 (250 mm) 0.156 (250 mm) 0.161 (250 mm) 0.170 (250 mm) 0.177 (250 mm) Ferrite 7200 cm3 5400 cm3 3384 cm3 3150 cm3 2592cm3 = 7 =
volume It can be seen from Table 1: as the air gap is increased, the coupling coefficient becomes smaller; however, the use of more ferrite material does not always result in better effect.
In Figs. 7(a)-(e), the amounts of ferrite materials are decreased sequentially, and the amount of ferrite material in the ferrite magnetic core layer in the scheme (e) is the lowest (2,592 cm3), and is only 9/25 of the highest amount of ferrite material used in the scheme (a); however, the coupling coefficient in the scheme (e) is only slightly lower than the coupling coefficient in the scheme (a) when the air gap is 100 mm, but is higher than the coupling coefficients in all other schemes in other cases. In summary, the scheme (e) is selected for the ferrite magnetic core layer structure of the cross-type magnetic path coupling mechanism according to the present invention. Hereunder the specific structural parameters of that scheme will be optimized.
The ferrite magnetic core layer in the cross-type magnetic path coupling mechanism described above consists of 8 ferrite strips that intersect each other in longitudinal and transverse direction to form a grid, but it is not an optimal structure.
Hereunder the structure in the scheme (e) will be further optimized, with the parameters defined above, including the side length of the ferrite magnetic core layer and length a of the rectangular coils, width b of the rectangular coils, number of turns n of the rectangular coils, outer margin w of the middle ferrite strips, ratio q of b to a, and ratio c of w to a, etc.
Example 2: through a lot of experiments, it can be known that in an under-saturated state, further increasing the width and thickness of the ferrite strips has little contribution to the coupling coefficient of the cross-type magnetic path coupling mechanism after the width and thickness of the ferrite strips reach certain values. Therefore, for the convenience of analysis, Mg-Zn ferrite strips with 30 mm width and 20 mm thickness, which can be obtained easily, are used in this example. The positions of the two middle ferrite strips are the key to the optimization. The curves shown in Figs. 8-9 are relation curves of coupling coefficient k vs. the ratio c of w to a of a cross-type magnetic path coupling mechanism under the conditions of air gap=200 mm and n=10 turns.
Wherein, Fig. 8 shows relation curves of k vs. c for different values of a with q=0.5; Fig.
9 shows relation curves of k vs. c for different values of q with a=600 mm. It can be seen from Figs. 8 and 9: for different values of a and different values of q, the coupling coefficient k of the cross-type magnetic path coupling mechanism reaches its maximum value (Max) at c=0.2. Thus, an optimal ferrite magnetic core layer structure is obtained, as shown in Fig. 10, i.e., the structure is optimal when the outer margin w of the two middle ferrite strips is equal to 0.2a.
Hereunder the shape of the cross-type magnetic path coupling mechanism will be further = 8 =
optimized under the premise that the optimized ferrite magnetic core layer structure shown in Fig. 10 is used. Mainly the side length of the ferrite magnetic core layer, the length a of the rectangular coils, and the width b of the rectangular coils will be optimized. For the convenience of analysis, assuming n=10 turns and air gap=200 mm, the relation curves of coupling coefficient k vs. q for different values of a are shown in Fig. 11. It can be seen from the curves in Fig. 11: the higher the value of a is, the higher the coupling coefficient k is; in addition, the coupling coefficient k reaches its maximum value at q=0.7, regardless of the value of a. Fig. 12 shows relation curves of coupling coefficient k vs. q for different values of air gap under the conditions of n=10 turns and a=600 mm. It can be seen from the figure: the smaller the air gap is, the higher the coupling coefficient k is; likewise, the coupling coefficient k always reaches its maximum value at q=0.7, regardless of the value of air gap. In summary, there is an optimal solution to the ratio q of width b to length a of the rectangular coils; namely, under the same condition, the coupling coefficient k of the cross-type magnetic path coupling mechanism is maximum when q=0.7.
The optimization and analysis described above are based on a condition that the number of turns of the rectangular coils is 10 turns, for the purpose of analyzing the influence of a specific characteristic parameter on the cross-type magnetic path coupling mechanism.
Though such a method is beneficial for the optimization and analysis process, the conclusion may not be universal owing to the particularity of the analysis process. To improve the universality of the optimization result, whether the result of optimization and analysis described above is still true will be verified by changing the condition of the number of turns n of the rectangular coils.
Fig. 13 shows the curves of k vs. c in 30 cases formed when q is changed from 0.5 to 1 in step of 0.01 and the number of turns of the rectangular coils is changed from 10 to 30 in step of 10 on the premise of a=600 mm and air gap=200 mm. It can be seen from the figure: all of the 30 curves simultaneously obtain the maximum value (Max) at c=0.2.
Thus, it is verified that the optimal ferrite magnetic core layer structure shown in Fig. 10 is independent of the number of turns of the rectangular coils and the ratio q, and is universally applicable to cross-type magnetic path coupling mechanisms. Fig.
13 shows curves of k vs. q in three cases (the number of turns n of the rectangular coils is 10, 20, and 30 respectively) with the optimal ferrite magnetic core layer structure shown in Fig.
15 on a premise of a=600 mm and air gap=200 mm. It can be seen from the figure: all of the three curves simultaneously obtain the maximum value at q=0.7. Therefore, the optimal ratio q of width b to length a of the rectangular coils is 0.7, and it is independent of the number of turns n of the rectangular coils and has universality.
Based on the above description, a schematic diagram of the optimal structure of the primary side energy emission cushion or secondary side energy collection cushion of the = 9 =
cross-type magnetic path coupling mechanism is shown in Fig. 15, which is a structural diagram of the example 3, wherein, q=0.7 and w=0.2a.
In the description of the present invention, it should be understood that the orientation or position relations indicated by terms "center", "longitudinal", "transverse", "length", "width", "thickness", "above", "below", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counter-clockwise", "axial", "radial", or "circumferential", etc., are based on the orientation or position relations indicated in the drawings. They are used only to describe the present invention and simplify the description, rather than indicate or imply that the involved device or element must have a specific orientation or must be constructed and operated in a specific orientation. Therefore, the use of these terms shall not be deemed as a limitation to the present invention.
In addition, the terms "first" and "second" are used only for description purpose, and shall not be interpreted as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Hence, the feature limited by "first" or "second" may explicitly or implicitly comprise at least one such feature. In the description of the present invention, "a plurality of' or "multiple" means at least two, such as two or three, etc., unless otherwise defined explicitly.
In the present invention, unless otherwise specified and defined explicitly, the terms "install", "connect", "fix", etc. shall be interpreted in their general meaning. For example, the connection may be fixed connection, detachable connection, or integral connection;
may be mechanical connection or electrical connection; may be direct connection or indirect connection via an intermediate medium, or internal communication or interactive relation between two elements, unless otherwise defined explicitly. The person skilled in the art may interpret the specific meanings of the terms in the context of the present invention.
In the present invention, unless otherwise specified and defined explicitly, a first feature being "above" or "below" a second feature may represent that the first feature and the second feature directly contact with each other or the first feature and the second feature contact with each other indirectly via an intermediate medium. In addition, a first feature being "over" a second feature may represent that the first feature is right over or diagonally over the second feature, or may only represent that the elevation of the first feature is higher than that of the second feature. A first feature being "under" a second feature may represent that the first feature is right under or diagonally under the second feature, or may only represent that the elevation of the first feature is lower than that of the second feature.
In the description of the present invention, the expressions of reference terms "an = 10 =
embodiment", "some embodiments", "an example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in these embodiments or examples are included in at least one embodiment or example of the present invention. In the description of the present application, the exemplary expression of the above terms may not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined appropriately in one or more embodiments or examples. Furthermore, in case of without mutual contradiction, the person skilled in the art may combine or assemble different embodiments or examples and features in different embodiments or examples described herein.
While the present invention is described above in some preferred embodiments, it should be noted that the person skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should be deemed as falling into the scope of protection of the present invention.
= 11 =
Claims (4)
1. A new magnetic path coupling mechanism for wireless electric energy transmission, characterized in that, it comprises: a primary side energy emission cushion and a secondary side energy collection cushion, which are arranged opposite to each other and in parallel with each other; both the primary side energy emission cushion and the secondary side energy collection cushion are of a two-layer structure, wherein, one layer is a coil layer formed by winding Litz wires, and the other layer is a magnetic core layer; both the coil layer and the magnetic core layer are of a centrosymmetric structure; wherein, the coil layer consists of two identical rectangular coils laminated orthogonally, and the magnetic core layer is a Sudoku-shaped grid layer consisting of 8 ferrite strips with the same length; the coil layer of the primary side energy emission cushion and the coil layer of the secondary side energy collection cushion are opposite to each other, and the opposite surfaces of the primary side energy emission cushion and the secondary side energy collection cushion are in mirror symmetry.
2. The new magnetic path coupling mechanism for wireless electric energy transmission according to claim 1, characterized in that, the length of the ferrite strips is equal to the length of the rectangular coils.
3. The new magnetic path coupling mechanism for wireless electric energy transmission according to claim 2, characterized in that, among the 4 ferrite strips in the middle of the magnetic core layer, the positions of any two ferrite strips parallel to each other meet the following condition:
w=0.2a wherein, w is the outer margin between two ferrite strips parallel to each other; a is the length of the rectangular coil.
w=0.2a wherein, w is the outer margin between two ferrite strips parallel to each other; a is the length of the rectangular coil.
4. The new magnetic path coupling mechanism for wireless electric energy transmission according to claim 3, characterized in that, the ratio of the width to the length of the rectangular coil is 0.7.
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| PCT/CN2017/091608 WO2018188202A1 (en) | 2017-04-11 | 2017-07-04 | New wireless electric energy transmission magnetic path coupling mechanism |
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| CN108878111B (en) * | 2018-06-05 | 2021-03-30 | 上海交通大学 | Overlapping wireless charging coil and electric energy transmission system |
| CN109300665A (en) * | 2018-10-30 | 2019-02-01 | 上海奕征新能源技术有限公司 | Wireless charging coil |
| CN109660032B (en) * | 2019-01-29 | 2022-04-12 | 哈尔滨工业大学 | Three-phase magnetic field coupling type wireless power receiving magnetic coupling mechanism |
| CN111799895B (en) * | 2020-07-14 | 2022-02-22 | 中国矿业大学 | Magnetic coupling structure and wireless power transmission system |
| CN113964949B (en) * | 2021-10-11 | 2023-09-19 | 三峡大学 | Loosely coupled wireless transmission device and application thereof |
| CN114089013B (en) * | 2022-01-21 | 2022-04-29 | 华中科技大学 | Zero offset suppression method based on magnetization micro-asymmetric magnetic core group mirror image matching |
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|---|---|---|---|
| EEER | Examination request |
Effective date: 20190121 |
|
| EEER | Examination request |
Effective date: 20190121 |