CN114336996A - Magnetic coupling structure of a dynamic wireless power supply system for electric vehicles - Google Patents

Abstract

The invention relates to a magnetic coupling structure of a dynamic wireless power supply system of an electric automobile, which comprises at least one vehicle-mounted auxiliary magnetic energy pickup mechanism arranged on the electric automobile and a plurality of primary side energy emission mechanisms buried underground on a running road surface, wherein the vehicle-mounted auxiliary magnetic energy pickup mechanism consists of a DD (direct d) separated coil and a square ferrite layer at the automobile end, each primary side energy emission mechanism consists of a group of emission coils and a circular ferrite layer at the ground end, and the emission coils and the DD separated coils are oppositely arranged for magnetic coupling to realize wireless power supply. Compared with the prior art, the invention has the advantages of high power, high efficiency, low fluctuation rate of mutual inductance, system loss reduction, material cost reduction and the like.

Description

Magnetic coupling structure of a dynamic wireless power supply system for electric vehicles

technical field

The invention relates to the field of wireless power supply for electric vehicles, in particular to a magnetic coupling structure of a dynamic wireless power supply system for electric vehicles.

Background technique

In the dynamic wireless power supply system of electric vehicles, the coupling structure is one of the core components of energy transmission. The mutual inductance of the primary and secondary coils will directly affect the energy efficiency characteristics of the wireless power transmission system. If the shape of the coil is improperly selected, the system will be greatly reduced. Therefore, in recent years, the design and research of the magnetic coupling structure in the dynamic wireless charging system is also very popular, such as the design of DD type coil, DDQ type coil, DLDD type coil, etc., these coils are effectively improved. The energy efficiency characteristics of the dynamic wireless charging system.

However, the existing technology only proposes a coupling structure design method for a specific coil, using a transmitting coil and a receiving coil with exactly the same size and shape, without considering that the shape and size of the coil in practical applications are often limited by the site environment, and at the same time, Using the same receiving coil and transmitting coil can achieve the power and efficiency required by the system, but this will also greatly increase the material cost. In practical applications, it is difficult for users to make the center of the ground coil and the coil at the vehicle end during driving. The center is perfectly aligned. When there is a deviation, the coupling coefficient of the system will be reduced and the power and efficiency of the real-time power supply will be affected.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a magnetic coupling structure of a dynamic wireless power supply system for an electric vehicle in order to overcome the above-mentioned defects in the prior art.

The object of the present invention can be realized through the following technical solutions:

A magnetic coupling structure of an electric vehicle dynamic wireless power supply system, the structure comprises at least one on-board secondary side magnetic energy pickup mechanism arranged on the electric vehicle and a plurality of primary side energy emitting mechanisms buried in the ground of the driving road, the on-board secondary side magnetic energy pickup mechanism The side magnetic energy pickup mechanism is composed of a DD separate coil and a car-end square ferrite layer. Each primary side energy transmitting mechanism is composed of a set of transmitting coils and a ground-end circular ferrite layer. The DD separate coil is magnetically coupled relative to the setting to realize wireless power supply.

The DD separate coil is coaxial with the center of the car-end square ferrite layer and is laid under the car-end square ferrite layer.

Each group of transmitting coils is composed of two circular coils connected in series and of the same size. The circular coils are coaxial with the center of the ground-end circular ferrite layer and are laid above the ground-end circular ferrite layer.

Adjacent primary energy transmitting mechanisms are arranged at equal intervals, and the center point of the transmitting coil of each primary energy transmitting mechanism is located on the same horizontal line in the overall extension direction of the transmitting coil. The arrangement direction of the two circular coils is perpendicular to the overall extension direction of the transmitting coils.

The DD separate coil is wound from the same Litz wire, and the winding directions of the two D-shaped coils of the DD separate coil are opposite.

The transmitting coil is wound by using the same Litz wire, and the two circular coils of the transmitting coil are wound in opposite directions.

The D-shaped coil of the DD separate coil is wound in the same direction as the circular coil at the corresponding position.

The primary side energy transmitting mechanism is set to 3 within a length of 1m, the radius of the circular coil in each group of transmitting coils is 8cm, the number of turns is 22, the turn spacing is 2mm, and the thickness of the circular ferrite layer at the ground end is 1.5cm.

The size of the DD separate coil is 100cm×18cm, the number of turns is 7, the interval between turns is 8mm, and the thickness of the square ferrite layer at the car end is 1.5cm.

The distance between the two circular coils in the transmitting coil is 5 cm, and the distance between the two D-shaped coils in the DD separate coil is 4 cm.

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

A novel coupling structure of a dynamic wireless power supply system for electric vehicles proposed by the present invention is verified by simulation to prove that the design of the magnetic coupling structure can meet the power and efficiency requirements of wireless dynamic charging of electric vehicles, the power is stable at 300W, and the efficiency reaches At the same time, on the premise of meeting the requirements of energy efficiency characteristics, the length of the Litz wire used in the wireless power transmission system of electric vehicles can be greatly reduced, which can not only reduce the system loss but also greatly reduce the material cost.

Description of drawings

Figure 1 is a schematic diagram of the magnetic coupling structure of a dynamic wireless power supply system for an electric vehicle.

FIG. 2 is a schematic diagram of the structure of the DD split coil.

Figure 3 shows the comparison results of the combined mutual inductance values of the coils.

Figure 4 is a simulation diagram of the coupling mechanism.

Figure 5 is a graph of mutual inductance fluctuations.

Figure 6 is a graph of energy pickup voltage and current.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The purpose of the present invention is to solve the problems of site limitation, high cost, and difficulty in daily maintenance of the prior art in practical applications. The laying of dynamic wireless charging tracks requires digging underground to lay the coils. The greater the required charging power, the more The larger the coil, the higher the cost and the maintenance of complex facilities hindering the promotion of dynamic wireless charging technology for automobiles. Therefore, the coupling coil is improved to reduce the amount of materials used while ensuring the transmission efficiency and output power, and improve the product's marketability. The competitiveness of dynamic wireless charging is a hot issue on the road to the popularization of dynamic wireless charging.

The present invention provides a magnetic coupling structure for a dynamic wireless power supply system for electric vehicles. For the problems that the cost of the coupling coil in the wireless dynamic charging system is relatively large and the size of the coil is limited by the site, the cost is greatly reduced when the product is put into application, and at the same time, the guarantee is The output power and efficiency of the system to meet the operation.

The magnetic coupling structure includes at least one vehicle-mounted secondary side magnetic energy pickup mechanism and multiple groups of primary side energy emission mechanisms; The center of the square ferrite layer is coaxial and placed under the square ferrite layer at the vehicle end; each group of primary side energy emitting mechanisms includes two circular coils of the same size in reverse series and the ground end circular ferrite layer body layer, the circular coil is coaxial with the center of the ground end circular ferrite layer and is placed above the ground end circular ferrite layer.

Two circular coils connected in series and of the same size constitute a group of transmitting coils, and multiple groups of transmitting coils are arranged at equal intervals. The arrangement direction of the two circular coils is perpendicular to the overall extension direction of the transmitting coils. The center point of the group of transmitting coils is located on the same horizontal line, and there is a certain distance between the two circular coils in each group of transmitting coils. mutual inductance.

The DD separate coil is used as the receiving coil. Based on the original DD coil structure, the optimal spacing is obtained by simulation analysis to be 4cm to reduce the adverse effect of the internal coupling of the coil.

The transmitting coil is wound from the same Litz wire, and the DD separate coil is also wound from the same Litz wire. The winding directions of the coils are the same. In this coupling structure, the height of the electric vehicle site is 12cm, and the primary side energy transmitting mechanism is buried underground to a depth of 3cm, so the vertical distance between the primary side energy transmitting mechanism and the secondary side power pickup mechanism is 15cm , the further improvement of the present invention lies in that the laying of the ground end round ferrite layer and the car end square ferrite layer provides a suitable path for the magnetic energy, effectively improving the coupling coefficient and anti-bias between the transmitting coil and the receiving coil. ability to move.

Example

As shown in FIG. 1 , the present invention relates to a novel magnetic coupling structure of an electric vehicle dynamic wireless power supply system, which includes an energy transmitting part, an energy pickup part and a control terminal.

The energy transmitting part is an intermittent structure composed of two circular coils connected in series. The diameter of the coil is 16cm, the number of turns is set to 26, and three sets of transmitting coils are evenly laid within a distance of 1m. The Litz wire contains multiple thin copper wires, which can greatly reduce the cross-sectional area of the winding under the condition of ensuring current resistance, reduce the overall diameter and reduce the volume of the coil to achieve optimal results. At the same time, a magnetic shielding mechanism based on ferrite material (ground-end circular ferrite layer) is laid under the transmitting coil, which can effectively improve the electromagnetic environment of the resonant wireless power transmission system and effectively shield the magnetic field in the non-working area. Leakage can reduce the magnetic field index in the non-working area, and can also enhance the magnetic field in the working area, making the coupling between the systems tighter.

The receiving coil is improved on the basis of the existing DD coil, and the winding method of the DD coil is shown in Figure 2. The existing DD coil structure is that two D-shaped coils are closely placed side by side, and the overall coil loop is wound by the same insulated wire. The magnetic core structure is generally a flat magnetic core, which is placed on the plane formed by the two D-shaped coils. Below or above, a horizontal magnetic circuit is provided for the two D-shaped coils. The improved DD separation structure of the present invention is formed by winding the two coils in series, the winding direction is reversed, and there is a certain gap inside the coil. , so that the magnetic lines of force form a complete two-way loop, making full use of the magnetic field strength generated by the coil energization, thereby reducing the negative impact of the internal coupling of the coil.

The receiving coil in the coupling mechanism adopts a DD separate coil with a length of 1m and a width of 40cm. A single coil is wound with 7 turns, and a high-frequency Liz copper wire is also used.

In order to verify whether the design method of the new coupling structure can achieve the required power, mutual inductance and stability of the electric vehicle wireless dynamic charging system, the present invention compares the experimental data and the simulation results based on the simulation platform.

3 is a comparison diagram of the mutual inductance between the present invention and other structural designs under the condition of consuming the same number of wires, wherein, scheme 2 is a combination scheme of DD separate coil + DD coil, and scheme 3 is a combination scheme of DD separate coil + rectangular coil. On the one hand, it can be seen from the figure that although Schemes 2 and 3 may have the potential to achieve performance similar to the present invention, their mutual inductance values are both lower than those of the DD split coil + the discontinuous circular combined coil. On the other hand, in the case where the same number of copper wires are used in the three schemes, the mutual inductance value of the present invention has far exceeded the value required by the system, indicating that on the premise of satisfying the mutual inductance value and coupling coefficient required by the system, The amount of wires used in the present invention will be less. When considering the cost of the coil for dynamic wireless charging, it is necessary to focus on the cost of the transmitting coil, because a large part of the cost of dynamic wireless charging comes from the large number of wires and magnetic cores used to make the transmitting coil. In addition, the contact area of the discontinuous circular combined transmitting coil in the present invention is much smaller than the contact area of the commonly used rectangular coil and DD coil, so the amount of ferrite material used in the magnetic shielding mechanism will also be greatly reduced, This means that the present invention can meet the requirements of high output power and efficiency with less material, and is more economical.

4 is a simulation diagram of the novel coupling structure of the present invention, and Table 1 is the detailed parameters of the magnetic coupling structure of the dynamic wireless charging system for electric vehicles,

Table 1 Parameters of Magnetic Coupling Mechanism

parameter transmitter coil receiver coil Coil size R=8cm 100cm×18cm number of turns twenty two 7 Turn spacing 2mm 8mm Ferrite thickness 1.5cm 1.5cm

The mutual inductance fluctuation between the transmitting coil and the receiving coil is shown in Figure 5. In the figure, the maximum mutual inductance of the transmitting coil and the receiving coil has reached more than 190 microhenries, the maximum value of the mutual inductance fluctuation is about 30 microhenry, and the highest fluctuation rate is 15%, which basically maintains the stability of the mutual inductance value and reaches the optimization standard. the feasibility of the present invention.

In the simulation, the voltage and current output values of the energy receiving end are shown in Figure 6. In the figure, the stable output voltage value is 35V, and the current value is stable at 7A, so the output power is stable at about 250W, which meets the power requirements for dynamic wireless charging of electric vehicles. , which verifies the feasibility of the present invention.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Any person familiar with the technical field can easily think of various equivalents within the technical scope disclosed by the present invention. Modifications or substitutions should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (10)

1. The magnetic coupling structure of the dynamic wireless power supply system of the electric automobile is characterized by comprising at least one vehicle-mounted auxiliary magnetic energy pickup mechanism arranged on the electric automobile and a plurality of primary side energy emission mechanisms buried underground on a running road surface, wherein the vehicle-mounted auxiliary magnetic energy pickup mechanism is composed of a DD (direct d) separated coil and a square ferrite layer at the automobile end, each primary side energy emission mechanism is composed of a group of emission coils and a circular ferrite layer at the ground end, and the emission coils and the DD separated coils are oppositely arranged to carry out magnetic coupling to realize wireless power supply.

2. The magnetic coupling structure of the dynamic wireless power supply system of the electric vehicle as claimed in claim 1, wherein the DD separating coil is coaxial with the center of the vehicle terminal square ferrite layer and is laid under the vehicle terminal square ferrite layer.

3. The magnetic coupling structure of the dynamic wireless power supply system of the electric automobile according to claim 1, wherein each group of the transmitting coils consists of two circular coils which are connected in series and have the same size, and the centers of the circular coils and the ground end circular ferrite layer are coaxial and are laid above the ground end circular ferrite layer.

4. The magnetic coupling structure of the dynamic wireless power supply system of the electric automobile according to claim 3, wherein adjacent primary energy emission mechanisms are arranged at equal intervals, the center point of the emission coil of each primary energy emission mechanism is located on the same horizontal line in the overall extension direction of the emission coil, and the arrangement direction of the two circular coils of each primary energy emission mechanism is perpendicular to the overall extension direction of the emission coil.

5. The magnetic coupling structure of the dynamic wireless power supply system of the electric vehicle as claimed in claim 3, wherein the DD split coil is formed by winding the same litz wire, and the two D-shaped coils of the DD split coil are wound in opposite directions.

6. The magnetic coupling structure of the dynamic wireless power supply system of the electric vehicle as claimed in claim 5, wherein the transmitting coil is formed by winding the same litz wire, and the two circular coils of the transmitting coil are wound in opposite directions.

7. The magnetic coupling structure of the dynamic wireless power supply system of the electric vehicle as claimed in claim 6, wherein the D-shaped coil of the DD separating coil has the same winding direction as the circular coil at the corresponding position.

8. The magnetic coupling structure of the dynamic wireless power supply system of the electric automobile according to claim 4, wherein 3 primary side energy emission mechanisms are arranged in a length of 1m, the radius of a circular coil in each group of emission coils is 8cm, the number of turns is 22, the turn-to-turn distance is 2mm, and the thickness of a ground end circular ferrite layer is 1.5 cm.

9. The magnetic coupling structure of the dynamic wireless power supply system of the electric automobile according to claim 2, wherein the DD split coil has a size of 100cm x 18cm, a number of turns of 7, a turn pitch of 8mm, and a thickness of a vehicle end square ferrite layer of 1.5 cm.

10. The magnetic coupling structure of the dynamic wireless power supply system of the electric vehicle as claimed in claim 4, wherein the distance between the two circular coils in the transmitting coil is 5cm, and the distance between the two D-type coils in the DD split coil is 4 cm.

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