CN111342567A - A dual-frequency omnidirectional wireless power transmission system - Google Patents

Abstract

The invention discloses a dual-frequency omnidirectional wireless power transmission system which comprises a transmitting end and a receiving end. The transmitting end comprises a first transmitting coil, a second transmitting coil and a first matching coil; the receiving end comprises a receiving coil and a second matching coil; the first emitting coil is adjusted to work at a first frequency by connecting a first lumped capacitor in series; the second transmitting coil is adjusted to work at a second frequency by connecting a second lumped capacitor in series; the receiving coil is adjusted to work at a first frequency or a second frequency by connecting a third lumped capacitor or a fourth lumped capacitor in series, and corresponds to the double-frequency coil of the transmitting end to achieve optimal transmission efficiency; the first matching coil and the second matching coil are respectively used for matching the impedance of the transmitting end and the impedance of the receiving end to a preset value. The invention adopts a double-frequency omnidirectional wireless power transmission system to respectively supply power for equipment with different working frequencies, and simultaneously solves the problems of transverse offset and angle offset of the system in the charging process.

Description

A dual-frequency omnidirectional wireless power transmission system

technical field

The invention belongs to the field of radio technology, and more particularly, relates to a dual-frequency omnidirectional wireless power transmission system.

Background technique

With the improvement of people's living standards and the development of science and technology, the information society is changing people's way of life and working habits, and at the same time, it also poses challenges to traditional houses. A more comfortable, convenient and safe home environment is more and more attractive people's attention. The rise of the Internet of Things technology has brought a new development space for the development of smart home, making it a new research hotspot. Smart home has become an inevitable trend and has penetrated into thousands of households. It can connect various devices in the home through wireless sensor network technology, not only can provide information interaction functions, but also people can view home information and information outside the home. It can quickly manage housework, monitor the home environment, and remotely control household electrical equipment.

At present, the emergence of the Internet of Things makes the functions of the smart home system more abundant, diversified and personalized. The power supply of various devices in the smart home is mostly in the form of wired power supply, and the wired charging and transmission process is easy to cause line aging, transmission loss, and easy friction to produce sparks, causing potential safety hazards and shortening the service life of the equipment. Therefore, it is urgent to seek a more flexible and convenient way of power transmission. As a way to realize power transmission without physical connection, wireless power transmission technology has the advantages of flexibility, convenience, safety and reliability, non-contact power supply, easy control and less external influence. It is one of the ten scientific research directions that will bring great changes to human production and way of life.

Based on the above analysis, it is a better choice to use wireless power transmission technology to supply power to multiple devices at the same time. However, the location of the devices is not fixed, and there will be a certain degree of lateral offset and angular offset, resulting in higher transmission efficiency. Low. At present, most researches on wireless power transmission systems focus on single-frequency omnidirectional power transmission, which can solve the problem of offset in the power transmission process. However, the operating frequencies of various devices are different, and transmitters with multiple frequencies are required to ensure the normal operation of the devices, which not only occupies space resources but also affects the appearance. Therefore, it is very important to design a wireless power transmission system that is not limited by location and can simultaneously charge devices with different operating frequencies efficiently.

SUMMARY OF THE INVENTION

Aiming at the defects of the prior art, the purpose of the present invention is to solve the technical problem that the existing radio transmission equipment is limited in location and cannot simultaneously charge equipment with different operating frequencies.

In order to achieve the above object, the present invention provides a dual-frequency omnidirectional wireless power transmission system, comprising: a transmitter and a receiver;

The transmitting end includes a first transmitting coil, a second transmitting coil and a first matching coil; the first transmitting coil and the second transmitting coil are connected by a first metal wire, they are both plane coils, and the two have the same parameters and are coaxial. are placed in parallel in the longitudinal direction, the first matching coil includes two planar coils with the same parameters and coaxially placed in parallel in the longitudinal direction and connected by a second wire, the first matching coil is located between the first transmitting coil and the second transmitting coil, The diameter of the plane coil included in the first matching coil is smaller than the diameter of the first transmitting coil; the plane where the first transmitting coil is located is the first plane;

The receiving end includes a receiving coil and a second matching coil that are coaxially and laterally placed on the same plane, the diameter of the second matching coil is smaller than the diameter of the receiving coil; the plane where the receiving coil is located is the second plane, and the first plane The included angle with the second plane is smaller than the preset angle, and on the premise that the included angle is determined to remain unchanged, the receiving end can work within an angular range of 360 degrees around the transmitting end;

A first lumped capacitor is welded on the side close to the first transmitting coil on the first metal wire, and a second lumped capacitor is welded on the side close to the second transmitting coil; the first transmitting coil and the first lumped capacitor are welded together. The capacitors are connected in series so that the operating frequency of the first transmitting coil is the first frequency, and the second transmitting coil and the second lumped capacitor are connected in series so that the operating frequency of the second transmitting coil is the second frequency.

Optionally, the receiving end further includes: a third lumped capacitor or a fourth lumped capacitor;

The receiving coil is connected in series with a third lumped capacitor, and the receiving end operates at the first frequency; or

The receiving coil is connected in series with a fourth lumped capacitor, and the receiving end operates at the second frequency.

Optionally, the planar coil included in the transmitting end can be wound into a square, circular, hexagonal or polygonal shape.

Optionally, the first matching coil is connected to a power supply to supply power to the receiving end of the first frequency and the receiving end of the second frequency.

Optionally, the receiving end is printed on the PCB.

Optionally, the first matching coil is used to match the impedance of the transmitting end so that the S11 parameter is lower than -10 dB.

Optionally, the preset angle is less than or equal to 30 degrees.

In general, compared with the prior art, the above technical solutions conceived by the present invention have the following beneficial effects:

(1) The dual-frequency omnidirectional wireless power transmission system provided by the present invention can realize efficient and efficient transmission of two frequency bands at the same time by reasonably designing the impedance matching circuit. The system is small in size, simple in fabrication and low in cost.

(2) The dual-frequency omnidirectional wireless power transmission system provided by the present invention can supply power to multiple devices at the same time while satisfying the simultaneous operation of two frequency bands, and is not limited by the placement position, which meets the needs of practical applications.

Description of drawings

FIG. 1 is a schematic diagram of a dual-frequency omnidirectional wireless power transmission system provided by an embodiment of the present invention;

2 is a schematic front view of a circular dual-frequency omnidirectional transmitting end provided by an embodiment of the present invention;

3 is a partial enlarged schematic diagram of a first lumped capacitor and a second lumped capacitor provided by an embodiment of the present invention;

4 is a circuit diagram of a dual-frequency omnidirectional transmitter provided by an embodiment of the present invention;

5 is a schematic diagram of a receiving end rotating around a transmitting end according to an embodiment of the present invention;

FIG. 6(a) is a transmission efficiency diagram of a time-dual-frequency system in which the receiving end of the square coil is rotated 360 degrees according to an embodiment of the present invention;

FIG. 6(b) is a transmission efficiency diagram of a dual-frequency system when the receiving end of the circular coil is rotated 360 degrees according to an embodiment of the present invention;

7 is a schematic diagram of a receiving end provided by an embodiment of the present invention when a tilt angle exists;

FIG. 8 is a transmission efficiency diagram when a receiving end has a tilt angle according to an embodiment of the present invention;

In all the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1 is the transmitting end, 10 is the first transmitting coil 10, 11 is the second transmitting coil, 12 is the first matching coil 12, 30 is the first lumped capacitance, 31 is the second lumped capacitance, 2 is the receiving end, 20 is the receiving coil, 21 is the second matching coil, 40 is the third lumped capacitance, and 41 is the fourth lumped capacitance.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

The invention discloses a dual-frequency omnidirectional wireless power transmission system, which includes a transmitter and a receiver. The transmitting end includes a first transmitting coil, a second transmitting coil and a first matching coil; the receiving end includes a receiving coil and a second matching coil; the first transmitting coil is adjusted to work at the first frequency by connecting the first lumped capacitor in series; the second The transmitting coil is adjusted to work at the second frequency by connecting the second lumped capacitor in series; the receiving coil is adjusted to work at the first or second frequency by connecting the third or fourth lumped capacitor in series, which is in phase with the dual-frequency coil at the transmitting end. corresponding to achieve optimal transmission efficiency; the first matching coil and the second matching coil are respectively used to match the impedance of the transmitting end and the receiving end to a predetermined value; the present invention adopts a dual-frequency omnidirectional wireless power transmission system for different distances and The wireless sensors of different powers are powered, and the problems of lateral offset and angular offset of the system during the charging process are solved at the same time.

In view of the above technical problems, the technical problem to be solved by the present invention is to provide a dual-frequency omnidirectional wireless power transmission system in view of the deficiencies of the prior art, which can ensure that multiple devices with different operating frequencies work simultaneously, and at the same time, can 360 It can supply power to the equipment, so as to achieve the purpose of reducing costs and reducing space utilization.

In order to achieve the above purpose, the present invention provides a dual-frequency omnidirectional wireless power transmission system, including a transmitter and a receiver; the transmitter includes a first transmitter coil, a second transmitter coil and a first matching coil; the receiver It includes a receiving coil and a second matching coil.

Further, the first transmitting coil and the second transmitting coil are arranged coaxially.

Further, the transmitting end can be wound into shapes such as square, circle, hexagon and polygon.

Further, the transmitter can charge the receiver in any direction of 360 degrees.

Further, the transmitting end has two resonant frequencies w01 and w02, and w02 is a frequency multiplied or nearly multiplied transmission frequency band of w01.

Further, the resonant frequency w01 is a series circuit formed by the first transmitting coil and the first lumped capacitor, the resonant frequency w02 is a series circuit formed by the second transmitting coil connected in series with the second lumped capacitor, and the two resonant frequencies are obtained simultaneously.

Further, the dual-frequency transmitter supplies power to the receivers with different frequencies at the same time.

Further, the receiving end is printed on the PCB board.

Further, the resonant frequency of the receiving end is a single frequency, and the third lumped capacitor or the fourth lumped capacitor is connected in series to adjust it to work at the first frequency or the second frequency, which corresponds to the dual-frequency coil at the transmitting end to achieve optimal transmission. efficiency.

The dual-frequency omnidirectional wireless power transmission system provided by the present invention, as shown in FIG. 1 , includes a transmitter 1 and a receiver 2 ; the transmitter 1 includes a first transmitter coil 10 , a second transmitter coil 11 and a first matching coil 12 . ; The receiving end 2 includes a receiving coil 20 and a second matching coil 21 .

In this embodiment, the first transmitting coil 10 and the second transmitting coil 11 are coaxially arranged. The length of the first transmitting coil 10 and the second transmitting coil 11 is 14 cm, the width is 14 cm, the distance between the two coils is 16 cm, the length of the first matching coil 12 is 10 cm, the width is 10 cm, and the height is 10 cm. The wire radius of the transmitting coil 10, the second transmitting coil 11 and the first matching coil 12 is 2 mm. The series circuit formed by the first transmitting coil 10 and the first lumped capacitor 30 makes the coil working frequency 13.56MHz. The resonant frequencies are obtained simultaneously. The first matching coil 12 is used to match the impedance of the transmitting end 1 so that the S11 parameter is lower than -10dB.

FIG. 2 is a schematic front view of a circular dual-frequency omnidirectional transmitting end. In this embodiment, the first transmitting coil 10 and the second transmitting coil 11 are coaxially arranged. The radius of the first transmitting coil 10 and the second transmitting coil 11 is 7 cm, the distance between the two coils is 16 cm, the radius of the first matching coil 12 is 5 cm, and the height is 10 cm. The wire radius of 11 and the first matching coil 12 is 2 mm. The series circuit formed by the first transmitting coil 10 and the first lumped capacitor 30 makes the coil working frequency 13.56MHz. The resonant frequencies are obtained simultaneously. The first matching coil 12 is used to match the impedance of the transmitting end 1 so that the S11 parameter is lower than -10dB.

FIG. 3 is a partial enlarged schematic diagram of the first lumped capacitor and the second lumped capacitor provided by the embodiment of the present invention. It can be seen that the first lumped capacitor 30 and the second lumped capacitor 31 are welded on the metal wire to be respectively connected to the first emitter The coil 10 and the second transmitting coil 11 are connected in series.

The receiving end 2 in the dual-frequency omnidirectional wireless power transmission system is printed on the FR4 board by using PCB technology, the resonant frequency of the receiving end 2 is a single frequency, and the receiving coil 20 is connected in series with the third lumped capacitor 40 or the fourth lumped capacitor 41 Adjust it to work at the first or second frequency, corresponding to the dual-frequency coil of the transmitter 1 to achieve optimal transmission efficiency. The second matching coil 21 adjusts the S11 value of the receiver to be lower than -10dB, and the center of the receiver and transmitter The distance is 17cm.

In order to analyze the transmission efficiency of the system, the equivalent circuit diagram of the transmitting coil of the dual-frequency omnidirectional system is shown in FIG. 4 , the first transmitting coil 10 and the second transmitting coil 11 respectively constitute the equivalent circuit 1 and the equivalent circuit 2 In this way, dual-frequency wireless power supply is realized.

Wherein V _S represents the input voltage; R _S ′ represents the internal resistance of the first matching coil itself, which can be 50 ohms; R _S , R _T1 and R _T2 represent the first matching coil, the first transmitting coil and the second transmitting coil respectively. resistance; L _S , L _T1 and L _T2 are the equivalent inductances of the first matching coil, the first transmitting coil and the second transmitting coil respectively; M _T12 is the mutual inductance between the first transmitting coil and the second transmitting coil; C _T1 and C _T2 represent the first lumped capacitance and the second lumped capacitance in series with the first transmitting coil and the second transmitting coil, respectively.

When analyzing the circuit model, all mutual inductances are considered, including the mutual inductances between the first matching coil 12 and the first transmitting coil 10 and the second transmitting coil 11, and the mutual inductance between the first matching coil 12 and the second matching coil 21. , the mutual inductance between the first matching coil 12 and the receiving coil 20, the mutual inductance between the first transmitting coil 10, the second transmitting coil 11 and the second matching coil 21, and the mutual inductance between the receiving coil 20 and the second matching coil 21 mutual inductance.

In order to verify the effectiveness of the proposed system, the receiver 2 is adjusted to 13.56MHz and 24.28MHz respectively, and the receiver 2 rotates 360 degrees around the transmitter 1 to monitor the system efficiency. The schematic diagram is shown in Figure 5. The transmission efficiencies of the square and circular coils at two frequencies are shown in Fig. 6(a) and Fig. 6(b), respectively. It can be found that the designed wireless power transmission system maintains basically the same transmission efficiency at any angle, and can supply power to devices with two frequencies. In addition, the transmission efficiency of the square system is higher than that of the circular system.

In a practical application scenario, the angle of the receiving end 2 may not be completely parallel to the transmitting end 1, but there will be an angle to a certain extent, as shown in FIG. 7 . In order to explore the law of transmission efficiency when the receiving end has a certain angle, the experimental verification is carried out. FIG. 8 is a transmission efficiency diagram when the receiving end has a tilt angle. It is found that the transmission efficiency of the system is basically unchanged when the receiving end 2 has a small angle of inclination. Wherein, the small angle here may be less than or equal to 30 degrees.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (7)

1. A dual-band omni-directional wireless power transmission system, comprising: a transmitting end and a receiving end;

the transmitting end comprises a first transmitting coil, a second transmitting coil and a first matching coil; the first transmitting coil and the second transmitting coil are connected through a first metal wire and are planar coils, the parameters of the first transmitting coil and the second transmitting coil are the same, the first transmitting coil and the second transmitting coil are coaxially and longitudinally arranged in parallel, the first matching coil comprises two planar coils which are connected through a second metal wire and have the same parameters, the planar coils are coaxially and longitudinally arranged in parallel, the first matching coil is positioned between the first transmitting coil and the second transmitting coil, and the diameter of the planar coil included by the first matching coil is smaller than that of the first transmitting coil; the plane where the first emitting coil is located is a first plane;

the receiving end comprises a receiving coil and a second matching coil which are coaxially, transversely and coplanar, and the diameter of the second matching coil is smaller than that of the receiving coil; the plane of the receiving coil is a second plane, the included angle between the first plane and the second plane is smaller than a preset angle, and the receiving end can work within an angle range of 360 degrees around the transmitting end on the premise that the size of the included angle is unchanged;

a first lumped capacitor is welded on one side, close to the first transmitting coil, of the first metal wire, and a second lumped capacitor is welded on one side, close to the second transmitting coil, of the first metal wire; the first transmitting coil and the first lumped capacitor are connected in series to enable the working frequency of the first transmitting coil to be a first frequency, and the second transmitting coil and the second lumped capacitor are connected in series to enable the working frequency of the second transmitting coil to be a second frequency.

2. The dual-band omni-directional wireless power transmission system according to claim 1, wherein the receiving end further comprises: a third lumped capacitor or a fourth lumped capacitor;

the receiving coil is connected with a third lumped capacitor in series, and the receiving end works at a first frequency; or

The receiving coil is connected with a fourth lumped capacitor in series, and the receiving end works at a second frequency.

3. The dual-band omni-directional wireless power transmission system according to claim 1, wherein the transmitting end comprises a planar coil wound in a square, circular, hexagonal or polygonal shape.

4. The dual-band omni-directional wireless power transmission system according to claim 1, wherein the first matching coil is connected to a power supply to supply power to a receiving end of a first frequency and a receiving end of a second frequency.

5. The dual-band omni-directional wireless power transmission system according to claim 1, wherein the receiving end is printed on a PCB board.

6. The dual-band omni-directional wireless power transmission system according to any one of claims 1 to 4, wherein the first matching coil is used to impedance match a transmitting end such that the S11 parameter is below-10 dB.

7. The dual-band omni-directional wireless power transmission system according to any one of claims 1 to 4, wherein the preset angle is less than or equal to 30 degrees.

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