Coupling device and wireless power transfer system

Abstract

The application provides a coupling device and a wireless power transmission system, wherein the coupling device comprises a transmitting coil and a receiving coil which is arranged at a distance from the transmitting coil, the transmitting coil and the receiving coil are coaxially arranged, the transmitting coil comprises a first coil which is wound by an enameled wire and a first hollow part which is formed inside an inner contour of the first coil; the receiving coil comprises a second coil which is wound by an enameled wire and a second hollow part which is formed inside an inner contour of the second coil; wherein a vertical projection of an outer contour of the second coil on the transmitting coil coincides with an inner contour of the first coil within an error range; the wireless power transmission system comprises the coupling device. Through reasonable configuration of the coupling device, the coupling capacity obtained by the wireless power transmission system is enhanced, and the efficiency of the wireless power transmission is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of wireless power transmission, and particularly relates to a coupling device for use in a wireless power transmission system. BACKGROUND

[0002] Wireless power transmission is a technology for power transmission through spatial electromagnetic field coupling. Its main advantages are: no need for plugging and un-plugging, simple and convenient to use; no electric spark, and can be used in flammable and explosive industrial environments; can transmit power in water, and can be applied to underwater applications such as marine equipment. Based on the above advantages, wireless power transmission is increasingly widely used.

[0003] Currently, the wireless power transmission technology mainly adopts electromagnetic induction near-field coupling technology to achieve high-efficiency power transmission of the system. The wireless power transmission technology includes a transmitting end and a receiving end. The transmitting end is usually composed of a resonant network of a coupling coil and a compensation capacitor, which generates a high-frequency alternating electromagnetic field under the excitation of a high-frequency excitation current. The receiving end is also a resonant network composed of a coupling coil and a compensation capacitor, which picks up the energy of the electromagnetic field generated by the transmitting end, and converts it into the required power form of the load side through high-frequency rectification. If the transmitting end and the receiving end work near the resonant frequency point, the wireless power transmission system can achieve high-efficiency power transmission.

[0004] The mutual inductance (M12) between the transmitting coil (L11) and the receiving coil (L22) of the wireless power transmission system directly affects the power coupling capability of the wireless power transmission system. For the wireless power transmission system, on the basis of meeting the established transmission working distance, the maximum degree of improvement of the system efficiency and the reduction of the size of the coupling coil have always been the goal pursued in practical applications. Generally, the coupling capability of the magnetic field coupling coil can also be represented by the coupling coefficient Under the same structural size limit, what form of transmitting coil structure and receiving coil structure can obtain the maximum mutual inductance and coupling coefficient directly affects the efficiency and other performances of the wireless power transmission system. SUMMARY

[0005] In order to solve the above problems, the present application provides a coupling device and a wireless power transmission system. Through the reasonable configuration of the coupling device, the coupling capability obtained by the wireless power transmission system is enhanced, and the efficiency of the wireless power transmission is improved.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A coupling device comprises a transmitting coil and a receiving coil spaced apart from the transmitting coil, the transmitting coil and the receiving coil are coaxially arranged, the transmitting coil comprises a first coil wound by enameled wire and a first hollow formed inside the inner contour of the first coil; the receiving coil comprises a second coil wound by enameled wire and a second hollow formed inside the inner contour of the second coil; wherein the vertical projection of the outer contour of the second coil on the transmitting coil coincides with the inner contour of the first coil within an error range.

[0008] As a further optimization of the present application, the error of the vertical projection of the outer contour of the second coil on the transmitting coil coinciding with the inner contour of the first coil is the deviation of the vertical projection of the outer contour of the second coil on the transmitting coil from the inner contour of the first coil, and the deviation is within 0.2 times the inner contour of the first coil.

[0009] As a further optimization of the present application, the cross section of the first coil is a circular ring, wherein the diameter of the outer contour of the first coil is 1.1-1.5 times the diameter of the inner contour of the first coil.

[0010] As a further optimization of the present application, the transmitting coil and the receiving coil are provided with a shielding layer of magnetic material on the back surface, and the receiving coil and the transmitting coil are provided with a shielding layer of magnetic material on the back surface.

[0011] A wireless power transmission system comprises the coupling device described above.

[0012] As a further optimization of the present application, further comprising a wireless transmitting end connected to a power grid and a wireless receiving end capable of receiving the power of the wireless transmitting end, the transmitting coil of the coupling device is arranged on the wireless transmitting end, and the receiving coil is arranged on the wireless receiving end.

[0013] As a further optimization of the application, the wireless transmitting end further comprises a transmitting end rectification filter circuit and a communication receiving module capable of receiving communication signals, the output end of the transmitting end rectification filter circuit is connected with an inverter circuit, the transmitting coil is connected with the output end of the inverter circuit, a sensor capable of sensing the positions of the transmitting coil and the receiving coil is arranged in the transmitting coil, the sensor forms an induction signal according to the distance between the transmitting coil and the receiving coil, and the sensor is connected with a transmitting end MCU to receive the induction signal formed by the sensor; the output end of the transmitting end MCU is electrically connected with the output end of the communication receiving module to receive the communication signals in the communication receiving module, the control end of the inverter circuit is electrically connected with the transmitting end MCU to control the frequency of the high-frequency alternating current converted in the inverter circuit; the transmitting end MCU comprises a judging module capable of receiving the induction signal and the communication signal and a control module electrically connected with the judging module, the judging module judges whether the wireless receiving end is in the working area according to the induction signal, if yes, the communication signal is converted into a judging signal and sent to the control module, and the control module converts the judging signal into a control signal to control the working frequency of the wireless transmitting end; if not, the judging module forms a reset judging signal and sends the reset judging signal to the control module, and the control module converts the reset judging signal into a control signal to control the wireless transmitting end to be in a standby state.

[0014] As a further optimization of the application, the receiving coil is built-in with an induction object capable of enhancing the induction intensity of the proximity sensor.

[0015] As a further optimization of the application, the receiving coil of the wireless receiving end is connected with a receiving end rectification filter circuit, the output end of the receiving end rectification filter circuit is connected with a DC / DC conversion circuit and an auxiliary power supply module, the output end of the auxiliary power supply module is connected with a receiving end MCU, and the receiving end MCU is connected with a communication transmitting module capable of transmitting communication signals to form the communication signals by transmitting the converted digital signals to the communication transmitting module.

[0016] As a further optimization of the application, the sensor is arranged at the center of the transmitting coil to avoid electromagnetic field interference.

[0017] Compared with the prior art, the application has the following advantages and positive effects:

[0018] 1. The coupling device can obtain a large current density through the size relationship between the transmitting coil and the receiving coil, and the current density on the receiving coil is positively correlated with the coupling ability (usually represented by mutual inductance M12 or coupling coefficient k) of the two coils, that is, even if the coupling effect between the transmitting coil and the receiving coil is optimal.

[0019] 2. The coupling device is reasonably configured to enhance the coupling ability obtained by the wireless power transmission system and improve the efficiency of the wireless power transmission.

[0020] 3、The wireless power transmission system can monitor the wireless receiving end equipment in real time, and transmit the inductive signal to the transmitting end MCU, and the transmitting end MCU controls and adjusts the working frequency and output gain of the transmitting end equipment according to the inductive signal and the communication signal, so that the wireless power transmission system works more safely and stably. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a perspective view of the coupling device of the application;

[0022] Figure 2 It is a perspective view of the coupling device of the application; Figure 1 It is a structural schematic view of the transmitting coil in the application;

[0023] Figure 3 It is a structural schematic view of the receiving coil in the application; Figure 1 It is a structural schematic view of the receiving coil in the application;

[0024] Figure 4 It is a sectional view of the coupling device of the application;

[0025] Figure 5 It is a view of the current density changing with the inner and outer diameter radius of the transmitting coil; Figure 1 ;

[0026] Figure 6 It is a view of the current density changing with the inner and outer diameter radius of the transmitting coil; Figure 2 ;

[0027] Figure 7 It is a view of the current density changing with the inner and outer diameter radius of the transmitting coil; Figure 3 ;

[0028] Figure 8 It is a view of the current density changing with the inner and outer diameter radius of the transmitting coil; Figure 4 ;

[0029] Figure 9 It is a view of the mutual inductance of the magnetic coupling coil changing with the inner and outer diameter radius of the transmitting coil;

[0030] Figure 10 It is a block diagram of the wireless power transmission system of the application.

[0031] In the above figures: 1, transmitting coil; 11, first hollow part; 12, first coil; 2, receiving coil; 21, second hollow part; 22, second coil; 3, shielding layer. DETAILED DESCRIPTION

[0032] In the following, the application will be specifically described through exemplary embodiments. However, it should be understood that the elements, structures and features in one embodiment can also be beneficially combined into other embodiments without further description.

[0033] In the description of the present application, it should be noted that the terms "inner", "outer", "upper", "lower", "front", "back", and the like indicate the positional or locational relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] As Figures 1-3 shown, the present application provides a coupling device mainly applied in a wireless power transmission system, which comprises a transmitting coil 1 and a receiving coil 2 arranged at intervals with the transmitting coil 1, the transmitting coil 1 and the receiving coil 2 are coaxially arranged, the transmitting coil 1 comprises a first coil 12 wound by enameled wire and a first hollow part 11 formed inside the inner contour of the first coil 12; the receiving coil 2 comprises a second coil 22 wound by enameled wire and a second hollow part 21 formed inside the inner contour of the second coil 22; wherein the vertical projection of the outer contour of the second coil 22 on the transmitting coil 1 coincides with the inner contour of the first coil 12 within an error range.

[0035] Further explanation, the error of the vertical projection of the outer contour of the second coil 22 on the transmitting coil 1 coinciding with the inner contour of the first coil 12 is the deviation of the vertical projection of the outer contour of the second coil 22 on the transmitting coil 1 relative to the inner contour of the first coil 12, and the deviation range is within 0.2 times of the inner contour of the first coil 12. The 0.2 times here includes two cases, that is, the vertical projection of the outer contour of the second coil 22 on the transmitting coil 1 is less than the inner contour of the first coil 12, and the deviation formed is less than 0.2 times of the inner contour of the first coil 12; the vertical projection of the outer contour of the second coil 22 on the transmitting coil 1 is not less than the inner contour of the first coil 12, and the deviation formed is less than 0.2 times of the inner contour of the first coil 12. The deviation here is the absolute value of the difference between the inner contour of the first coil and the outer contour of the second coil.

[0036] For example, if the first coil 12 and the second coil 22 are both circular, the deviation of the vertical projection of the outer contour of the second coil 22 on the first coil 1 from the inner contour of the first coil 12 is within 0.2 times the inner contour of the first coil 12, i.e., the diameter of the outer contour of the second coil 22 is 0.8-1.2 times the diameter of the inner contour of the first coil 12. If the diameter of the outer contour of the second coil 22 is 9 cm, the diameter of the inner contour of the first coil 12 should be 7.2-10.8 cm, and the difference between the inner contour of the first coil and the outer contour of the second coil is within 0.2 times the outer contour of the second coil. Similarly, when the first coil and the second coil are of other shapes, since the first coil and the second coil are coaxially arranged and have the same shape, any two points corresponding to the inner contour of the first coil and the outer contour of the second coil have a difference within 0.2 times the distance from the inner contour of the first coil to the coaxial point.

[0037] In the above, the transmitting coil 1 and the receiving coil 2 are both hollow coils formed by winding enameled wire, wherein the enameled wire is not specifically limited to a certain model, as long as the enameled wire has a conductive wire and an insulating layer covering the conductive wire for insulation, which is within the scope of the present application. In the present application, the specific shape of the transmitting coil 1 and the receiving coil 2 is not specifically limited, and the transmitting coil 1 and the receiving coil 2 only need to have a hollow portion in the middle. In addition, the transmitting coil 1 and the receiving coil 2 of the present application are both provided with a shielding layer 3 of magnetic material on the two sides away from each other, i.e., the shielding layer 3 of magnetic material is provided on the side of the transmitting coil 1 away from the receiving coil 2 and on the side of the receiving coil 2 away from the transmitting coil 1. The material of the shielding layer 3 is generally a high-permeability material such as ferrite, which is tightly placed on the transmitting coil or the receiving coil. The shape of the shielding layer can be circular, annular, square or other shapes, but generally should be able to cover the outer diameter of the transmitting or receiving coil.

[0038] Further, as shown in Figure 4 In the present application, the cross section of the first coil 12 is preferably circular, and the diameter of the outer contour of the first coil 12 is 1.1-1.5 times the diameter of the inner contour of the first coil 12. The cross section of the second coil 22 can also be circular.

[0039] Continuing to refer to Figure 4Specifically, the outer diameter of the first coil 12 is defined as D11, and the inner diameter as D12. The outer diameter of the second coil 22 is defined as D21, and the inner diameter as D22. The interval between the transmitting coil 1 and the receiving coil 2 is defined as H. When D11 = (1.1-1.5)D12, a large coupling effect can be obtained between the transmitting coil 1 and the receiving coil 2. When D11 = 1.25D12, the coupling force between the transmitting coil 1 and the receiving coil 2 is the largest. When D11 = 1.1D12 and D11 = 1.5D12, the current density obtained between the transmitting coil 1 and the receiving coil 2 is relatively large, and the coupling force reaches a correspondingly large value. In addition, it should be noted that in this invention, the interval H between the first coil 12 and the second coil 22 is not specifically limited, and it can be selected according to the specific object and actual requirements.

[0040] The following is combined Figures 5-8 Detailed explanation. Figures 5-8 The outer diameter of the second coil (hereinafter referred to as the outer diameter) is 9cm, while the inner diameter (hereinafter referred to as the inner diameter) is selected successively as 4cm, 5cm, 6cm and 7cm. Through Figures 5-8 As shown in the figure, when the inner and outer diameters of the first coil change sequentially, the current density is highest when the inner diameter of the first coil is equal to the outer diameter of the second coil, which is only 9 cm. Furthermore, the current density is also relatively high when the inner diameter of the first coil is around 8.5 cm to 9.5 cm. The current density is directly proportional to the coupling capability of the coupling device; a higher current density results in a relatively higher coupling capability. Meanwhile, in... Figures 5-8 It can also be seen that when the outer contour diameter of the first coil 12 is 1.1-1.5 times the inner contour diameter of the first coil 12, its current density is larger and the corresponding coupling ability is also larger.

[0041] Combination Figure 8 and Figure 9 As shown, Figure 8 This is a graph showing the trend of current density as a function of the inner and outer diameter radii of the first coil when the outer diameter of the second coil is 9 cm and the inner diameter is 7 cm. Figure 9 This is a graph showing the trend of mutual inductance M12 of the magnetic coupling coil as a function of the inner and outer diameter radii of the first coil when the outer diameter of the second coil is 9cm and the inner diameter is 7cm. From... Figure 8 and Figure 9 A comparison shows that, Figure 8 The magnitude distribution of current density in the first coil corresponds to the inner and outer diameters of the coil. Figure 9 The inner and outer diameters of the first coil corresponding to the mutual inductance value of the magnetic coupling coil are consistent, meaning that the current density and the mutual inductance value of the magnetic coupling coil are positively correlated. For example... Figure 9As shown, when the inner contour diameter of the first coil is 9 cm, the mutual inductance value M12 of the magnetic coupling coil is the largest, and the coupling coefficient That is, the coupling coefficient is proportional to the mutual inductance value M12 of the magnetic coupling coil, when M12 is the largest, the coupling coefficient is also the largest, and therefore, at this time, the coupling capacity of the coupling device is also the largest. At the same time, in Figures 4-9 It can also be seen in that when the outer contour diameter of the first coil 12 is 1.1-1.5 times the inner contour diameter of the first coil 12, the mutual inductance value of the magnetic coupling coil is larger, and the corresponding coupling capacity is also larger.

[0042] Through the above Figure 10 In the above, the cross section of the transmitting coil and the receiving coil is taken as a circular example for specific description and actual verification, and it can be known that when the inner contour of the first coil in the transmitting coil coincides with the inner contour of the second coil in the receiving coil, the coupling capacity is the largest.

[0043] Referring to Figure 10 , it is a block diagram of the wireless power transmission system of the present application. As shown in Figure 10 , the wireless power transmission system of the present application comprises the coupling device described above. The function and effect of the coupling device have been specifically described above, and will not be repeated here. The wireless power transmission system installs the coupling device described above, and the coupling capacity reaches the best, thereby improving the transmission efficiency of the wireless power transmission system.

[0044] Continuing to refer to ​The wireless power transmission system further comprises a wireless transmitting end connected to the power grid, and a wireless receiving end capable of receiving power from the wireless transmitting end, the transmitting coil of the coupling device is arranged in the wireless transmitting end, and the receiving coil is arranged in the wireless receiving end. The wireless transmitting end further comprises a transmitting end rectifier filter circuit and a communication receiving module capable of receiving a communication signal, the output end of the transmitting end rectifier filter circuit is connected to an inverter circuit, the output end of the inverter circuit is connected to the transmitting coil, and a sensor capable of sensing the positions of the transmitting coil and the receiving coil is arranged in the transmitting coil. The sensor is preferably arranged at the center of the transmitting coil to avoid the influence of electromagnetic induction. The sensor is connected to a transmitting end MCU to receive the sensing signal formed by the sensor. The transmitting end MCU is electrically connected to the output end of the communication receiving module to receive the communication signal in the communication receiving module, and is electrically connected to the control end of the inverter circuit to control the frequency of the high-frequency alternating current converted in the inverter circuit. The transmitting end MCU comprises a judgment module capable of receiving the sensing signal and the communication signal, and a control module electrically connected to the judgment module. If the wireless receiving end is in the working area, the judgment module judges according to the sensing signal, and if the wireless receiving end is in the working area, the judgment module converts the communication signal into a judgment signal and sends it to the control module. The control module converts the judgment signal into a control signal to control the working frequency of the wireless transmitting end. If the wireless receiving end is not in the working area, the judgment module forms a reset judgment signal and sends it to the control module. The control module converts the reset judgment signal into a control signal to control the wireless transmitting end to be in a standby state.

[0045] Through the arrangement of the sensor in the transmitting coil, the wireless power transmission system can monitor in real time whether the wireless receiving end equipment is removed or placed, and transmit the sensing signal to the transmitting end MCU. The transmitting end MCU controls and adjusts the working frequency and output gain of the transmitting end equipment according to the sensing signal and the communication signal, so that the wireless power transmission system works more safely and stably.

[0046] In addition, in order to enable the wireless transmitting end to more quickly sense the wireless receiving end, the above-mentioned receiving coil is built-in with a sensing object capable of enhancing the sensing strength of the proximity sensor.

[0047] Meanwhile, the receiving coil of the wireless receiving end is connected to a receiving end rectifier filter circuit, the output end of the receiving end rectifier filter circuit is connected to a DC / DC conversion circuit and an auxiliary power supply module, the output end of the auxiliary power supply module is connected to a receiving end MCU, the receiving end MCU is connected to a communication transmitting module capable of transmitting a communication signal, so as to transmit the converted digital signal to the communication transmitting module to form a communication signal. In addition, an auxiliary power supply is also arranged in the wireless transmitting end to supply power to the transmitting end MCU.

[0048] In the above, the receiving coil couples the energy in the transmitting coil electromagnetic field to the receiving end through magnetic coupling, and becomes direct current through the rectification filter circuit, and is converted into the required stable voltage for the load end through DC / DC conversion, to supply power to the load end.

Claims

1. A coupling device comprising a transmit coil and a receive coil disposed in spaced relation to the transmit coil, characterized by: The transmitting coil and the receiving coil are coaxially arranged, the transmitting coil comprises a first coil wound by enameled wire and a first hollow formed inside the inner contour of the first coil; the receiving coil comprises a second coil wound by enameled wire and a second hollow formed inside the inner contour of the second coil; wherein the vertical projection of the outer contour of the second coil on the transmitting coil coincides with the inner contour of the first coil within an error range, the error of the vertical projection of the outer contour of the second coil on the transmitting coil coinciding with the inner contour of the first coil is the deviation of the vertical projection of the outer contour of the second coil on the transmitting coil relative to the inner contour of the first coil, the deviation range is within 0.2 times of the inner contour of the first coil, the cross section of the first coil is circular ring shape, wherein the outer contour diameter of the first coil is K times of the inner contour diameter of the first coil, 1.25 < K ≤ 1.5, the outer contour diameter of the second coil is 0.8-1.2 times of the inner contour diameter of the first coil.

2. The coupling device of claim 1, wherein: The transmitting coil and the receiving coil are provided with shielding layers of magnetic conductive material on the facing away surfaces, and the receiving coil and the transmitting coil are provided with shielding layers of magnetic conductive material on the facing away surfaces.

3. A wireless power transfer system, characterized by: The coupling device comprises the coupling device of claim 1 or 2.

4. A wireless power transfer system according to claim 3, characterised in that: The wireless transmitting end connected to the power grid and the wireless receiving end capable of receiving the power of the wireless transmitting end are further included, the transmitting coil of the coupling device is arranged in the wireless transmitting end, and the receiving coil is arranged in the wireless receiving end.

5. A wireless power transfer system according to claim 4, wherein: The wireless transmitting end further comprises a transmitting end rectification filter circuit and a communication receiving module capable of receiving a communication signal, the output end of the transmitting end rectification filter circuit is connected with an inverter circuit, the output end of the inverter circuit is connected with the transmitting coil, the transmitting coil is provided with a sensor capable of sensing the positions of the transmitting coil and the receiving coil, the sensor forms an induction signal according to the distance between the transmitting coil and the receiving coil, and the sensor is connected with a transmitting end MCU to receive the induction signal formed by the sensor; The transmitting end MCU is electrically connected with the output end of the communication receiving module to receive the communication signal in the communication receiving module, and is electrically connected with the control end of the inverter circuit to control the frequency of the high-frequency alternating current converted in the inverter circuit; the transmitting end MCU comprises a judgment module capable of receiving the induction signal and the communication signal and a control module electrically connected with the judgment module, the judgment module judges whether the wireless receiving end is in the working area according to the induction signal, if yes, the communication signal is converted into a judgment signal and sent to the control module, the control module converts the judgment signal into a control signal to control the working frequency of the wireless transmitting end, and if not, the judgment module forms a reset judgment signal and sends the reset judgment signal to the control module, and the control module converts the reset judgment signal into a control signal to control the wireless transmitting end to be in a standby state.

6. The wireless power transfer system of claim 5, wherein: The receiving coil is provided with a sensing object capable of enhancing the sensing strength of the proximity sensor.

7. The wireless power transfer system of claim 5 or 6, wherein: The receiving coil of the wireless receiving end is connected with a receiving end rectification filter circuit, the output end of the receiving end rectification filter circuit is connected with a DC / DC conversion circuit and an auxiliary power supply module, the output end of the auxiliary power supply module is connected with a receiving end MCU, the receiving end MCU is connected with a communication transmitting module capable of transmitting a communication signal to transmit the converted digital signal to the communication transmitting module to form a communication signal.

8. The wireless power transfer system of claim 5, wherein: The sensor is arranged at the center of the transmitting coil where electromagnetic field interference can be avoided.

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