A wireless power transfer coupling coil structure with high interoperability

Abstract

The application provides a wireless power transmission coupling coil structure with high interoperability, which is composed of double-layer coil overlap; one layer of the coil is a butterfly-shaped coil structure for generating or receiving a parallel magnetic field component, and the other layer of the coil is an octagonal coil structure for generating or receiving a vertical magnetic field component; the butterfly-shaped coil structure and the octagonal coil structure are placed in staggered overlap and are connected in series with each other. The application further reduces a zero magnetic flux region, increases a transmission area, reduces mutual inductance influence between the two layers of the coil, forms decoupling, effectively reduces the total length of the coil and line impedance, realizes good interoperability of the coil structure with various types of planar coils, and the like.

Description

Technical Field

[0001] This invention belongs to the field of wireless power transmission, and in particular relates to a wireless power transmission coupling coil structure with high interoperability. Background Technology

[0002] Many charging devices rely on direct plugging for frequent charging, and the long-term wear and tear on the wires poses a significant risk of electric shock and even death to charging operators. The emergence of wireless power transfer technology has significantly improved this situation. Wireless power transfer technology uses a soft medium in space (electromagnetic field, microwave) to transmit electrical energy to the load without wire contact, overcoming the safety issues associated with wired transmission. Wireless power transfer technology can be broadly classified into three categories based on its transmission principle: First, electromagnetic induction, based on the principle of loosely coupled transformers, has a short transmission distance and is currently the most widely used, suitable for short-distance and high-power transmission; second, resonant coupling, based on the principle of high resonant energy, has a longer transmission distance and higher transmission power, and can bypass obstacles during transmission; third, microwave radiation, based on the mechanism of antenna transmission and reception, has a long transmission distance, but suffers from high losses and low transmission efficiency in the transmission path, cannot bypass obstacles, and is harmful to organisms and the surrounding environment.

[0003] Currently, electromagnetic induction-based wireless power transfer is the most widely used application, with numerous charging standards established in industries such as wireless charging for electric vehicles. The coupling mechanism is the core component of electromagnetic induction-based wireless power transfer. Due to differences in design approaches among researchers, the interoperability between coupling coils of different shapes is poor. Currently, inductive wireless charging coils mainly rely on vertical magnetic field paths (square coils) and parallel magnetic field paths (DD coils) for power transfer. When these two types of coils are coupled, the coupling coefficient can be zero, and power can only be received after a certain distance is offset. Mobile bidirectional wireless charging power supplies, acting as third-party power transporters, are installed on mobile devices (such as electric vehicles). As the receiver of wireless charging, they receive power and store it in the battery. They then move to a designated location to act as transmitters, wirelessly powering the load. Their emergence allows for flexible relocation of wireless charging locations and more flexible load placement. However, mobile bidirectional wireless charging power supplies inevitably interact with coupling coils of different shapes during operation, making the design of a third-party coil capable of interoperating with both types of coils essential. Currently, domestic and international research generally employs two methods for designing coupling mechanisms with high interoperability: First, through control. This involves controlling the switching of two types of coils or controlling the forward and reverse series connection of two rectangular coils (0 degrees phase angle in forward series and 180 degrees in reverse series). However, this method is prone to switching failures due to frequent switching. Second, through the direct superposition of two types of coils. For example, a DDQ coil can be coupled to two types of coils simultaneously. This method avoids control measures, but it creates a large overlap area and a zero-flux region. Furthermore, the longer coil transmission path results in significant line impedance, affecting transmission performance. Therefore, minimizing coil length while improving interoperability becomes crucial. Summary of the Invention

[0004] This invention proposes a wireless power transfer coupling coil structure with high interoperability. Based on achieving interaction with various planar coils, it further reduces the zero flux region, increases the transmission area, and reduces the mutual inductance between the two layers of coils to achieve decoupling. At the same time, it effectively reduces the total coil length and line impedance, thus achieving good interoperability between this coil structure and various planar coils.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A highly interoperable wireless power transfer coupling coil structure comprises two overlapping coil layers. One layer is a butterfly coil structure for generating or receiving a parallel magnetic field component, and the other layer is an octagonal coil structure for generating or receiving a perpendicular magnetic field component. The butterfly coil structure and the octagonal coil structure are staggered and overlapped, and connected in series. The double-layer coil can be connected to a high-frequency power supply at both ends to serve as an electromagnetic transmitting part containing a high-frequency power supply, or it can be connected to a load at both ends to serve as an electromagnetic receiving part containing a load.

[0006] Furthermore, both the butterfly coil structure and the octagonal coil structure are formed by winding a single wire.

[0007] Furthermore, the butterfly coil structure and the octagonal coil structure are staggered and overlapped, reducing the overlapping area and increasing the independent area, while reducing the zero magnetic flux area to expand the transmission area.

[0008] Furthermore, the overlapping sections of the butterfly coil structure and the octagonal coil structure are perpendicular. This effectively avoids mutual inductance interference, reduces mutual interference between the two coils, and achieves decoupling between the coils.

[0009] Furthermore, the geometric centers of the butterfly coil structure and the octagonal coil structure are at the same point.

[0010] Furthermore, the inscribed circle radius of the butterfly coil structure is the same as the circumscribed circle radius of the octagonal coil structure.

[0011] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a highly interoperable wireless power transfer coupling coil structure. It abandons the previous method of switching between multiple coils via a switch, instead using a single wire winding to achieve efficient interoperability with planar coils of various types and sizes. Based on achieving interoperability with planar coils of various types and sizes, an interleaved superimposed winding method is employed. This reduces the zero-flux region in the overlapping coil portion, reduces the mutual inductance between two layers of coils, and reduces the total coil length and coil loss. This structure exhibits good interoperability with both coil structures relying on perpendicular and parallel magnetic field paths for power transfer. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a highly interoperable wireless power transfer coupling coil structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the distribution area of ​​the wireless power transfer coil with high interoperability according to an embodiment of the present invention; Figure 3This is a comparison graph of the magnetic flux density of the coil and the DD coil in the embodiment of the present invention, and the change of the magnetic flux density of the DD coil and the DD coil with respect to the X component; Figure 4 This is a comparison graph showing the magnetic flux density of the coil and the square coil in the embodiment of the present invention, and the change of the magnetic flux density of the square coil and the square coil with respect to the X component. Detailed Implementation

[0013] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0014] To make the purpose and features of this invention patent clearer and easier to understand, the specific embodiments of this invention patent will be further described below with reference to the accompanying drawings.

[0015] The present invention discloses a wireless power transfer coupling coil structure with high interoperability, which adopts a double-layer coil structure composed of overlapping double-layer coils; the overall shape is square. The double-layer coil structure includes a butterfly coil structure that generates or receives parallel magnetic field components and an octagonal coil structure that generates or receives vertical magnetic field components. The butterfly coil structure can be understood as a coil structure where the central portion of each of the four sides of a square coil is recessed towards the center of the coil. The magnetic field generated by the double-layer coil structure can achieve efficient interoperability with planar coils of various structures, has a small zero-flux region and low line impedance, enabling efficient energy transfer.

[0016] The butterfly coil structure that generates or receives parallel magnetic field components is made of a single wire, which solves the problem of a large zero flux region in traditional DD type coils. Through this special winding method, the zero flux region is reduced, the transmission area is increased, and parallel magnetic field components can be generated and received, enabling interoperability with DD type coils.

[0017] An octagonal coil structure that generates or receives vertical magnetic field components is also made of a single wire. It can generate and receive vertical magnetic field components and is interoperable with coils of other types, such as circular or square coils.

[0018] The present invention comprises two coil structures that are overlapped and connected in series. That is, one coil structure is the upper layer, and the other is the lower layer. These two layers are staggered and overlapped, and connected in series. This staggered overlap means that there are no overlapping positions between the coils, only overlapping areas. This reduces the overlapping area of ​​the two coil structures and increases the independent area.

[0019] The two coils are overlapped perpendicularly, meaning the overlapped coils are perpendicular to each other. This design can achieve decoupling and reduce mutual inductance.

[0020] The two-layer coils connected in series can be connected to a high-frequency power source at both ends to serve as an electromagnetic transmitting part containing a high-frequency power source; or they can be connected to a load at both ends to serve as an electromagnetic receiving part containing a load.

[0021] In the optimal design, the staggered and overlapping coil structure is symmetrical both vertically and horizontally; the geometric centers of the two coil structures are at the same point, and the inscribed radius of the butterfly coil is the same as the circumscribed radius of the octagonal structure. 。 This ensures that the magnetic field remains as uniform as possible.

[0022] Compared to traditional DDQ structures and switch-switch coil structures, this structure can increase the transmission area, reduce the zero flux region, shorten the coil length and line impedance, eliminate potential risks of switching, reduce line losses, and control costs.

[0023] Specific application examples: like Figure 1 As shown, butterfly coil 1 is on the lower layer and octagonal coil 2 is on the upper layer; butterfly coil 1 is used to generate or receive parallel magnetic field components; octagonal coil 2 is used to generate or receive vertical magnetic field components; the two coils are staggered and intersect perpendicularly where they overlap; this perpendicular distribution ensures that the magnetic field around butterfly coil 1 does not pass through octagonal coil 2 when forming a loop, and the magnetic field around octagonal coil 2 does not pass through butterfly coil 1 when forming a loop, thereby reducing the influence between the two layers of coils.

[0024] like Figure 2 As shown, regions ⑤ and ⑥ are the overlapping regions of the double-layer coils; regions ②, ④, ⑦, and ⑨ are the independent regions of the octagonal coil 2; and regions ①, ③, ⑧, and ⑩ are the independent regions of the butterfly coil 1. By adopting an interleaved distribution, the overlapping part of the double-layer coils and the zero-flux region are reduced. Under the premise of achieving interoperability, the length of the coil is shortened, thereby reducing the total impedance of the coil and enabling the coil to transmit efficiently.

[0025] like Figure 3 As shown, the magnetic flux density variation trends in the "X" direction are compared between the DD coil and the interleaved coil of this embodiment, when they are of the same size, with DD coils interacting with each other and DD coils interacting with interleaved coils. It can be seen that the magnetic flux variation trends in the two cases are basically the same, which shows that the two coils can produce good interoperability.

[0026] like Figure 4As shown, the magnetic flux density variation trends in the "X" direction are compared between square coils and the interleaved coil of this embodiment, when they are of the same size, with square coils interacting with each other and square coils interacting with interleaved coils. It can be seen that the magnetic flux variation trends in the two cases are basically the same, which shows that the two types of coils can produce good interoperability.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wireless power transfer coupling coil structure with high interoperability, characterized in that, It consists of two overlapping coils; one coil is a butterfly coil structure for generating or receiving parallel magnetic field components, and the other coil is an octagonal coil structure for generating or receiving vertical magnetic field components; the butterfly coil structure and the octagonal coil structure are staggered and overlapped to reduce the overlapping area and increase the independent area, while reducing the zero magnetic flux area to expand the transmission area, and they are connected in series; the overlap of the butterfly coil structure and the octagonal coil structure adopts a vertical overlap method.

2. The wireless power transfer coupling coil structure with high interoperability according to claim 1, characterized in that, The butterfly coil structure and the octagonal coil structure are each made by winding a single wire.

3. The wireless power transfer coupling coil structure with high interoperability according to claim 1, characterized in that, The geometric centers of the butterfly coil structure and the octagonal coil structure are at the same point.

4. The wireless power transfer coupling coil structure with high interoperability according to claim 1, characterized in that, The inscribed circle radius of the butterfly coil structure is the same as the circumscribed circle radius of the octagonal coil structure.

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