CN204721105U - Insert the asymmetric wireless power transmission systems of repeating coil - Google Patents

Abstract

The utility model discloses an asymmetric wireless power transmission system inserted into a relay coil in the technical field of magnetic coupling resonance wireless power transmission. The relay coil and the transmitting coil are coaxial and in the same plane, and mainly solve the problem of wireless power transmission in which the size of the transmitting coil is larger than that of the receiving coil. The problem of low transmission efficiency of the system at medium and long distances, the utility model enhances the mutual inductance coefficient between adjacent coils and improves the coupling degree between coils by inserting a relay coil coaxial and coaxial with the transmitting coil in the system, thereby improving the coupling degree between the coils. The transmission efficiency of the system is improved, and the coaxial and coplanar structure of the relay coil and the transmitting coil saves space size, which is more conducive to the practical application of the wireless power transmission system.

Description

Asymmetric wireless power transmission system with relay coil inserted

technical field

The utility model belongs to the technical field of magnetic coupling resonance wireless power transmission, relates to an asymmetric wireless power transmission system inserted into a relay coil, in particular to a relay coil in an asymmetric wireless power transmission system in which the size of the transmitting coil is larger than that of the receiving coil The new design structure, the relay coil and the transmitting coil are coaxial and in the same plane, so as to save space and improve the transmission efficiency of the wireless power transmission system.

Background technique

With the development of science and technology, wireless power transmission technology has attracted more and more people's attention, especially in November 2006, Marin Soliacic of the Massachusetts Institute of Technology and his research team at the Industrial Physics Forum of the American Physical Society used The principle of magnetic coupling resonance successfully lit a 60W light bulb about 2m away from the power supply. Later, this technology was called WiTricity, which aroused a wave of research on wireless power transmission systems. With the in-depth research on magnetic coupling resonance technology, experts and scholars from various countries have successively developed high-power wireless energy transmission devices, such as maglev trains, tailless home appliances, implanted medical equipment, electric vehicles and mobile devices.

At present, there are three ways to realize wireless power transmission at home and abroad:

1. Radio-wave Wireless Power Transmission (RWPT) - the basic principle is to use radio waves (such as microwaves) instead of wires to realize the transmission of electric energy. It can realize high-power and long-distance electric energy transmission. It is a radio wave energy transmission method that has been studied more at present, but its transmission attenuation is serious, the efficiency of energy transmission is not high, and it has a great impact on the biological environment.

2. Electromagnetic Induction Wireless Power Transmission (EI-WPT) - its basic principle is to use the principle of electromagnetic induction to transmit electric energy from the primary winding to the secondary winding, the two windings are tightly coupled, and the transmission efficiency is very high High, but the transmission distance is short and can only be limited to the range of millimeters or centimeters. At the same time, the structural dimensions of the two coil windings require precise dimensions.

3. Magnetically-coupled resonant wireless power transmission (MCR-WPT) - the principle is to adjust the transmitting coil and receiving coil into a resonant system, when the oscillation frequency of the transmitting coil and the natural frequency of the receiving coil At the same time, the system will generate resonance, so that the energy only oscillates between the transmitting coil and the receiving coil with the same resonance frequency, so as to transmit energy, and there will be no energy interaction with other non-resonant objects. It makes up for the shortcomings of the short transmission distance of the electromagnetic induction wireless power transmission technology, increases the transmission distance to the range of meters, and also overcomes the low transmission efficiency of the microwave wireless power transmission method, greatly improving the transmission efficiency of the system.

The transmission efficiency is one of the main performance indicators of the magnetically coupled resonant wireless power transfer system, and the mutual inductance coefficient between the coils will affect the transmission efficiency of the system.

The study found that the transmission efficiency of the wireless power transmission system with the size of the transmitting coil larger than the size of the receiving coil is lower than that of a wireless power transmission system in which the transmitting and receiving devices are completely symmetrical under the same circumstances, and its transmission distance will also be affected. However, in the actual wireless power transmission system, the transmitting It is difficult to achieve complete symmetry between the coil and the receiving coil. Adding a relay coil can effectively solve the problem of low transmission efficiency of the system. It improves the mutual inductance coefficient between the coils and enhances the coupling degree between the coils, thereby enabling the system to operate at a higher efficiency. to transfer.

To sum up, in practical applications of wireless power transfer systems, it is difficult to achieve complete symmetry between the transmitting device and the receiving device. For example, when wirelessly charging mobile devices such as mobile phones, the size of the transmitting coil is larger than that of the receiving coil. In this asymmetric wireless power transmission system, the transmission efficiency will decrease, and with the increase of the transmission distance, the transmission efficiency of the system will drop sharply, and the popularization and application of the wireless power transmission system will be limited. , we have to find a technical structure to realize the above-mentioned solution—to allow the wireless power transmission system with the size of the transmitting coil larger than the size of the receiving coil to achieve high-efficiency transmission at medium and long distances.

Utility model content

The purpose of this utility model is to propose an asymmetrical wireless power transmission system with a relay coil inserted in order to solve the problem that the mutual inductance coefficient is small and the transmission efficiency of the system is low when the wireless power transmission system with the size of the transmitting coil is larger than the size of the receiving coil for energy transmission . The system inserts a relay coil coaxial and in the same plane as the transmitting coil in the magnetically coupled resonant wireless power transmission system in which the transmitting coil is larger than the receiving coil, so that the mutual inductance coefficient between the transmitting end and the receiving end is enhanced, thereby improving the transmission efficiency of the system. At the same time, The utility model can also save space and reduce the volume of the system, which is more conducive to the practical application of wireless power transmission.

In order to achieve the above goals, the technical solution adopted by the utility model is: an asymmetric wireless power transmission system inserted into a relay coil, the wireless power transmission system includes a transmitting device, a relay device and a receiving device; the transmitting device includes A high-frequency signal generator, an impedance matching network, a power amplifier, and a transmitting coil. One side of the transmitting coil is connected to the high-frequency signal generator through an impedance matching network, and the other side resonates with the receiving coil to make the energy in the form of electromagnetic waves Oscillate between two coils; the relay device includes a relay coil, the relay coil is coaxial and coplanar with the transmitting coil, has the same number of turns and pitch, and the relay coil is different in radius from the transmitting coil; The receiving device includes a receiving coil, a load device and a power meter. The radius of the receiving coil is smaller than that of the transmitting coil, and the number of turns and the pitch of the turns are the same as the transmitting coil. One side of the receiving coil is connected to the load device, and Generate resonance with the transmitting coil; the transmitting coil, relay coil, and receiving coil are on the same horizontal axis, and the distance between the transmitting coil and the receiving coil is 1m.

According to the power transmission system described in the present invention, the impedance matching network is an active matching network, which is composed of a source follower, an emitter follower and a buffer composed of active and passive devices;

According to the power transmission system described in the utility model, the impedance matching network is a passive matching network composed of inductors and capacitors.

According to the power transmission system described in the utility model, the relay coil is wound on the outer layer of the transmitting coil.

According to the power transmission system described in the present invention, the receiving coil is a multi-turn spiral coil, connected in series with a matching capacitor, and directly connected to an AC load device; or the receiving coil is supplied to a DC load device or circuit through a rectifier circuit; The rectification circuits described above include half-wave rectification, full-wave rectification and bridge rectification.

According to the power transmission system described in the present invention, the transmitting coil, the relay coil and the receiving coil utilize their own equivalent resistance at high frequency, parasitic capacitance, matching capacitance and their own inductance to form an oscillation circuit, and the transmitting coil, the relay coil and the The receiving coils have the same resonant frequency.

According to the power transmission system of the present invention, the transmitting coil, the relay coil and the receiving coil are all multi-turn coils.

The beneficial effects of the utility model are:

1. The asymmetric wireless power transmission system inserted into the relay coil proposed by the utility model can enhance the mutual inductance coefficient of adjacent coils between the magnetic coupling resonant wireless power transmission system in which the transmitting coil is larger than the receiving coil size, so that the system can achieve higher efficiency to transfer.

2. Compared with the existing technology, the asymmetric wireless power transmission system inserted into the relay coil proposed by the utility model can maintain a high mutual inductance between adjacent coils during medium and long-distance transmission, thereby making the transmission efficiency significantly improved The improvement further solves the problem that the transmission efficiency of the system is restricted by the size of the transmitting coil and the receiving coil, and improves the utilization efficiency of electric energy in the system.

Description of drawings

FIG. 1 is a structural diagram of an asymmetric magnetic coupling resonant wireless power transmission system.

Fig. 2 is a schematic diagram of the utility model in which the relay coil and the transmitting coil are coaxial and on the same plane.

Fig. 3 is an equivalent circuit model diagram of the asymmetric wireless power transmission system inserted with a relay coil of the present invention.

Fig. 4 is a simulation diagram of the transmission efficiency of the asymmetric wireless power transmission system inserted with the relay coil according to the utility model, which varies with frequency.

Fig. 5 is an experimental diagram of the transmission efficiency of the asymmetric wireless power transmission system inserted with a relay coil according to the present invention, which varies with frequency.

Fig. 6 is a simulation and experiment comparison diagram of the transmission efficiency of the asymmetrical wireless power transmission system inserted with the relay coil according to the frequency of the utility model.

Detailed ways

In order to make the content and advantages of the technical solution of the utility model clearer, the asymmetric wireless power transmission system of the utility model with a relay coil inserted will be further described in detail below in conjunction with the drawings and specific embodiments. It should be emphasized that the following descriptions are only illustrative, not intended to limit the scope of the present utility model and its application.

The wireless power transmission system described in the utility model includes a transmitting device, a relay device and a receiving device. The transmitting device comprises a high-frequency signal generator, an impedance matching network, a power amplifier and a transmitting coil, one side of the transmitting coil is connected to the high-frequency signal generator through an impedance matching network, and the other side resonates with the receiving coil, so that Energy oscillates between the two coils in the form of electromagnetic waves; the relay device includes a relay coil, the relay coil is coaxial and coplanar with the transmitting coil, has the same number of turns and pitch, and has different radii; the receiving device It includes a receiving coil, a load device and a power meter. The radius of the receiving coil is smaller than that of the transmitting coil, and its parameters such as the number of turns and the distance between turns are the same as those of the transmitting coil. Generate resonance with the transmitting coil; the transmitting coil, relay coil and receiving coil are on the same horizontal axis.

The transmitting coil, relay coil and receiving coil utilize their equivalent resistance at high frequency, parasitic capacitance, matching capacitance and their own inductance to form an oscillation circuit, and the transmitting coil, relay coil and receiving coil have the same resonant frequency. The centers of the transmitting coil, the receiving coil and the relay coil are on the same horizontal axis, when the distance and the transmission distance between the transmitting coil and the receiving coil change, due to the strong interaction between the transmitting coil and the relay coil, and between the relay coil and the receiving coil mutual inductance, the system can still transmit with high efficiency.

As shown in Figure 1, the transmitting coil is on the left and the receiving coil is on the right. The size of the transmitting coil is larger than that of the receiving coil, that is, the transmitting device and the receiving device are not completely symmetrical, and their transmission efficiency will be lower than that of the same size. In actual life and applications, people put forward greater requirements for the dexterity and convenience of electronic products, and the same is true for the application of wireless power transmission. The size of the receiving end is often smaller than that of the transmitting end.

As shown in Figure 2, the coaxial and coplanar structure of the relay coil and the transmitting coil of the present invention greatly enhances the mutual inductance between the relay coil and the transmitting coil, realizes the amplification of the source current, improves the transmission efficiency of the system, and The space size is saved, the volume of the system is reduced, and it is more conducive to practical application.

As shown in Figure 3, the transmitting coil is on the left, the relay coil is in the middle, and the receiving coil is on the right. Both the transmitting end and the receiving end of the system adopt a series structure, M ₁₂ is the mutual inductance coefficient of the transmitting coil and the relay coil, and M ₂₃ is the relay coil and the mutual inductance coefficient of the receiving coil, Vs is the high frequency voltage source, Rs is the internal resistance of the voltage source, R ₁ , R ₂ , R ₃ are the equivalent internal resistances of the transmitting coil, relay coil and receiving coil respectively, C ₁ , C ₂ and C ₃ are the external capacitances of the three coils, L ₁ , L ₂ , and L ₃ are the self-inductances of the three coils, and R _L is the load resistance of the system.

The equivalent circuit model analysis steps of the asymmetric wireless power transmission system inserted into the relay coil of the present invention are as follows:

1. The equivalent circuit of the system is analyzed to obtain the following equation:

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}\\ \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{ccc}{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}& \mathrm{<span\; class="notranslate">\; j\&omega;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; j\&omega;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}& {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; two</span>}}& \mathrm{<span\; class="notranslate">\; j\&omega;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 33</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; j\&omega;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}\end{array}\right]\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}\end{array}\right]$

Among them, V _S is the output voltage of the high-frequency signal generator, Z ₁₁ , Z ₂₂ , and Z ₃₃ are the loop impedances of the transmitting coil loop, the relay coil loop, and the receiving coil loop respectively, and their expressions are respectively: $Z_{\mathrm{twenty\; two}}=R_2+\mathrm{j\&omega;}{L}_2+\frac{1}{\mathrm{j\&omega;}{C}_2},Z_{33}=R_3+\mathrm{j\&omega;}{L}_3+\frac{1}{\mathrm{j\&omega;}{C}_3}+R_L;$ M ₁₂ is the mutual inductance coefficient of the transmitting coil and the relay coil, M ₂₃ is the mutual inductance coefficient of the relay coil and the receiving coil, i ₁ , i ₂ , and i ₃ are the loop currents of the transmitting coil loop, the relay coil loop and the receiving coil loop respectively. When the system works in the resonance state, it satisfies: $\mathrm{\&omega;}{L}_2=\frac{1}{\mathrm{\&omega;}{C}_2},\mathrm{\&omega;}{L}_3=\frac{1}{\mathrm{\&omega;}{C}_3}.$

2. Solving the determinant in the step 1, i ₁ , i ₂ , and i ₃ can be obtained as follows:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; vs.</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span>}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&omega;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span>}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}\mathrm{<span\; class="notranslate">\; vs.</span>}}{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span>}$

3. Calculate the loop current in step 2 to obtain the input power, output power and transmission efficiency respectively:

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; vs.</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span>}$

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; =</span>\frac{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}\mathrm{<span\; class="notranslate">\; vs.</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}}{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

$\mathrm{<span\; class="notranslate">\; \&eta;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}<span\; class="notranslate">\; =</span>\frac{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}$

4. The radii of the transmitting coil, the relay coil and the receiving coil in the system are a, b, and c respectively, the distance between the transmitting coil and the receiving coil is D, and the distance between the transmitting coil and the relay coil is d, then the relay coil and The distance between the receiving coils is Dd, then the mutual inductance between the transmitting coil and the relay coil is: $m_{12}={\mathrm{\&mu;}}_0{\left(\mathrm{ab}\right)}^{\frac{1}{2}}\stackrel{\mathrm{\&pi;}}{\sqrt{0^2}}\frac{(2{\sin }^2\mathrm{\&theta;}-1)\mathrm{d\&theta;}}{{\left({1-{k_1}^2\sin }^2\mathrm{\&theta;}\right)}^{\frac{1}{2}}},$ in $k_1^2=\frac{4\mathrm{ab}}{d^2+{(a+b)}^2};$ The mutual inductance between the relay coil and the receiving coil is: $m_{\mathrm{twenty\; three}}={\mathrm{\&mu;}}_0{\left(\mathrm{bc}\right)}^{\frac{1}{2}}\stackrel{\mathrm{\&pi;}}{\sqrt{0^2}}\frac{(2{\sin }^2\mathrm{\&theta;}-1)\mathrm{d\&theta;}}{{(1-{k_2}^2{\sin }^2\mathrm{\&theta;})}^{\frac{1}{2}}},$ in $k_2^2=\frac{4\mathrm{bc}}{{(\mathrm{D.}-d)}^2+{(b+c)}^2}.$

In the asymmetric wireless power transmission system inserted into the relay coil of the present utility model, since the transmitting coil and the relay coil are coaxial and in the same plane, so d=0, then the mutual inductance M between the transmitting coil and the relay coil is enhanced, by the step ₃ The transmission efficiency expression of the medium system shows that the efficiency is related to M ₁₂ and M ₂₃ , and M ₁₂ and M ₂₃ are related to d and Dd respectively. When the distance d between the transmitting coil and the relay coil decreases, the distance between the relay coil and the receiving coil When the distance Dd increases, M ₁₂ increases, and M ₂₃ decreases. When other parameters of the system remain unchanged, the transmission efficiency changes with the change of d. From the expression of efficiency, when d increases, the efficiency η is almost no change, and then as d increases, the efficiency decreases sharply. It can be seen that when the distance d between the transmitting coil and the relay coil is very close, the transmission efficiency can reach a larger value. Considering the size and volume limitations of the actual system , the utility model maintains the relay coil and the transmitting coil on the same axis and plane, which not only makes the transmission efficiency of the system reach a higher value, but also saves the volume of the system, which is more conducive to the practical application of the system.

The radii of the transmitting coil and the receiving coil of the present utility model are respectively a=30cm, c=10cm, the radius of the relay coil is b=50cm, the turn pitch P ₀ =2cm, the number of turns is N=8 turns, and the radius of all copper wires is r=3mm , the frequency of the excitation source is set to f ₀ =10.6MHz, the distance between the transmitting coil and the receiving coil, that is, the system transmission distance D=1m, and the centers of all the coils are on the same horizontal axis. The transmitting coil, the receiving coil and the capacitor form an LC series resonant circuit, so that the coil resonance occurs near 10.6MHz.

As shown in Figure 4, the transmission efficiency of the system reaches the highest value near the resonant frequency point, and its value is close to 1, which greatly improves the transmission of this asymmetric magnetic coupling resonant wireless power transmission system in which the size of the transmitting coil is larger than that of the receiving coil efficiency.

In the experimental model of the utility model, a sine wave signal of 10.6 MHz is generated by a signal generator, which is amplified by a power amplifier and then loaded into the transmitting coil, whereby the input power can be obtained, the receiving coil is connected to a power meter, and the output power is measured by the power meter. The ratio of the two is calculated to obtain the transmission efficiency of the system.

As shown in Figure 5, the transmission efficiency of the experimental model of the utility model reaches the highest value near the resonance frequency point, and its value is close to 0.9, that is, the system can transmit with higher efficiency.

As shown in FIG. 6 , the simulation of the asymmetric wireless power transmission system inserted in the relay coil of the present invention is basically consistent with the experimental data, and is also consistent with the theoretical analysis results. It shows that in the asymmetrical system, the transmission efficiency of the system is greatly improved by inserting the structure of the relay coil coaxial and coplanar with the transmitting coil.

The utility model designs a structure in which a relay coil coaxial with the transmitting coil is inserted into the magnetic coupling resonance wireless power transmission system in which the size of the transmitting coil is larger than the receiving coil, and the mutual inductance coefficient between the coils is enhanced, thereby enhancing the coupling coefficient of the system and The transmission efficiency is high, and the space size is saved, which is more conducive to the practical application of the wireless power transmission system.

The above is only a preferred embodiment of the utility model, but the scope of protection of the utility model is not limited thereto, any equivalent modification or Transformation should be covered within the protection scope of the present utility model.

Claims (7)

1. insert an asymmetric wireless power transmission systems for repeating coil, it is characterized in that, described wireless power transmission systems comprises an emitter, a relay and a receiving system;

Described emitter comprises high frequency signal generator, impedance matching network, power amplifier and transmitting coil, the side of described transmitting coil is connected to high frequency signal generator by impedance matching network, opposite side and receiving coil produce resonance, and energy is vibrated in the form of an electromagnetic wave between two coils;

Described relay comprises a repeating coil, and described repeating coil is arranged with the coaxial isoplanar of transmitting coil, has the identical number of turn and pitch of turn, and described repeating coil is different from transmitting coil radius;

Described receiving system comprises receiving coil, load equipment and power meter, the radius of the radius ratio transmitting coil of described receiving coil is little, its number of turn is identical with transmitting coil with pitch of turn, and described receiving coil side is connected to load equipment and power meter, and opposite side and transmitting coil produce resonance;

Described transmitting coil, repeating coil, receiving coil are on same level axle, and the distance of transmitting coil and receiving coil is 1m.

2. a kind of asymmetric wireless power transmission systems inserting repeating coil according to claim 1, it is characterized in that, described impedance matching network is passive matching network, is made up of electric capacity and inductance.

3. a kind of asymmetric wireless power transmission systems inserting repeating coil according to claim 1, it is characterized in that, described impedance matching network is active matching network, and the source follower be made up of active, passive device, emitter follower and buffer are formed.

4. a kind of asymmetric wireless power transmission systems inserting repeating coil according to claim 1, is characterized in that, described repeating coil is in the outer coiling of transmitting coil.

5. a kind of asymmetric wireless power transmission systems inserting repeating coil according to claim 1, it is characterized in that, described receiving coil is multiturn helical coil, a matching capacitance of connecting, and directly connects AC load equipment.

6. a kind of asymmetric wireless power transmission systems inserting repeating coil according to claim 1, it is characterized in that, described receiving coil is by a rectification circuit supply DC load equipment, and described rectification circuit comprises halfwave rectifier, full-wave rectification and bridge rectifier.

7. a kind of asymmetric wireless power transmission systems inserting repeating coil according to claim 1, it is characterized in that, described transmitting coil, repeating coil and receiving coil utilize himself in high frequency equivalent resistance, parasitic capacitance, matching capacitance and own inductance composition oscillating circuit; Transmitting coil, repeating coil and receiving coil have identical resonance frequency.