Magnetic coupler and wireless charging system

Abstract

Provided in the present application are a magnetic coupler and a wireless charging system. The magnetic coupler comprises a first transmitting coil, a second transmitting coil, a Litz wire and a receiver coil; the first transmitting coil and the second transmitting coil are coaxially arranged; the Litz wire is wound around the first transmitting coil and the second transmitting coil and is connected to the first transmitting coil and the second transmitting coil; when the magnetic coupler is in operation, the receiver coil is located within a magnetic field formed by the first transmitting coil and the second transmitting coil. The first transmitting coil and the second transmitting coil can be connected in series to ensure the axial misalignment resistance of the magnetic coupler, thus reducing the effect of misalignment on the coupling performance of the magnetic coupler; in operation, the first transmitting coil and the second transmitting coil form a charging area by means of superposition and the receiver coil of the magnetic coupler is placed within the charging area formed by the first transmitting coil and the second transmitting coil, thus ensuring the coupling capability of the magnetic coupler.

Description

Magnetic coupler and wireless charging system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application with application number 202311226168.X filed with the State Intellectual Property Office of China on September 21, 2023, entitled “Magnetic Coupler and Wireless Charging System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of wireless charging technology, and in particular to a magnetic coupler and a wireless charging system. Background Art

[0004] In the field of underwater vehicles, developing devices with charging capabilities can eliminate the need for periodic salvage and charging of underwater vehicles. Wireless charging technology, due to its convenience and high transmission efficiency, is widely used in underwater docking station charging systems. In wireless charging systems for underwater vehicles and docking stations, the inductive link generated by the magnetic coupler affects the charging power and efficiency of wireless charging. Therefore, how to design the magnetic coupler to ensure both power and efficiency is a challenge that needs to be addressed.

[0005] Related magnetic coupler designs typically use circular or rectangular transmitting and receiving coils. These coils must be aligned during operation to establish an inductive link when the coupler is powered on. This magnetic coupler design can be applied to wireless charging systems to charge underwater vehicles.

[0006] However, the design of this magnetic coupler is easily affected by the size of the underwater vehicle hull and underwater natural phenomena, which causes the magnetic coupler to offset, reducing the charging power and charging efficiency of wireless charging, thereby reducing the reliability of the wireless charging system of the underwater vehicle and the underwater docking station.

[0007] Summary of the Invention

[0008] The purpose of this application is to provide a magnetic coupler and a wireless charging system to address the deficiencies in the above-mentioned related technologies, so as to solve the problem in the related technologies that the offset of the magnetic coupler affects the reliability of the wireless charging system.

[0009] To achieve the above objectives, the technical solutions adopted in the embodiments of the present application are as follows:

[0010] Some embodiments of the present application provide a magnetic coupler comprising: a first transmitting coil, a second transmitting coil, a Litz wire, and a receiving coil;

[0011] The first transmitting coil and the second transmitting coil are coaxially arranged;

[0012] The Litz wire is wound around the first transmitting coil and the second transmitting coil and connects the first transmitting coil and the second transmitting coil;

[0013] When the magnetic coupler is in operation, the receiving coil is located in the magnetic field formed by the first transmitting coil and the second transmitting coil, and is coaxial with the first transmitting coil and the second transmitting coil. The radius of the receiving coil is smaller than the radius of the first transmitting coil, and the radius of the receiving coil is smaller than the radius of the second transmitting coil.

[0014] As a possible implementation manner, the first transmitting coil and the second transmitting coil are wound in an underwater docking station, and the receiving coil is embedded in an autonomous underwater vehicle.

[0015] As a possible implementation, the first transmitting coil and the second transmitting coil are both annular coils, and the Litz wire is configured to be wound around the first transmitting coil and the second transmitting coil in the same direction, so that the directions of the magnetic fields generated by the magnetic coupler during operation are consistent.

[0016] As a possible implementation manner, the radius of the first transmitting coil is the same as the radius of the second transmitting coil, and a straight-line distance between the center of the first transmitting coil and the center of the second transmitting coil is the same as the radius of the first transmitting coil or the radius of the second transmitting coil.

[0017] As a possible implementation manner, guide ferrites are respectively provided on the inner wall of the first transmitting coil and the inner wall of the second transmitting coil.

[0018] As a possible implementation, the magnetic coupler further includes: a cylindrical fixing member;

[0019] The first transmitting coil and the second transmitting coil are sleeved on both ends of the fixing member along the axial direction of the fixing member.

[0020] As a possible implementation manner, the fixing member is provided with an opening for receiving the receiving coil.

[0021] Some other embodiments of the present application provide a wireless charging system, the wireless charging system comprising: a transmitting device, a receiving device, and the magnetic coupler described in any one of the first aspects above;

[0022] The first output end of the transmitting device is connected to one end of the Litz wire of the magnetic coupler, and the second output end of the transmitting device is connected to the other end of the Litz wire of the magnetic coupler;

[0023] The first connection end of the receiving coil is connected to the first input end of the receiving device, and the second connection end of the receiving coil is connected to the second input end of the receiving device.

[0024] As a possible implementation, the transmitting device is arranged in an underwater docking station, and the receiving device is arranged in an autonomous underwater vehicle.

[0025] As a possible implementation, the transmitting device includes: a DC power supply, an inverter unit, and a resonance unit;

[0026] The positive electrode of the DC power supply is connected to the first input terminal and the second input terminal of the inverter unit, and the negative electrode of the DC power supply is connected to the third input terminal and the fourth input terminal of the inverter unit;

[0027] The first output terminal and the second output terminal of the inverter unit are connected to the input terminal of the resonance unit;

[0028] The first output end of the resonance unit is connected to one end of the Litz wire of the magnetic coupler, and the second output end of the resonance unit is connected to the other end of the Litz wire of the magnetic coupler.

[0029] As a possible implementation, the inverter unit includes: a first field effect transistor, a second field effect transistor, a third field effect transistor, and a fourth field effect transistor;

[0030] The drain of the first field effect transistor and the drain of the third field effect transistor are connected to the positive electrode of the DC power supply, the source of the first field effect transistor is connected to the drain of the second field effect transistor, and the source of the second field effect transistor is connected to the negative electrode of the DC power supply;

[0031] The source of the third field effect transistor is connected to the drain of the fourth field effect transistor, and the source of the fourth field effect transistor is connected to the negative electrode of the DC power supply;

[0032] The source of the first field effect transistor is also connected to the first input terminal of the resonant unit;

[0033] The source of the third field effect transistor is also connected to the second input end of the resonance unit.

[0034] As a possible implementation, the resonance unit includes: an inductor, a first capacitor, and a second capacitor;

[0035] One end of the inductor is connected to the first output end of the inverter unit, and the other end of the inductor is connected to one end of the first capacitor and one end of the second capacitor;

[0036] The other end of the first capacitor is connected to the second output end of the inverter unit and one end of the Litz wire of the magnetic coupler;

[0037] The other end of the second capacitor is connected to the other end of the Litz wire of the magnetic coupler.

[0038] As a possible implementation, the receiving device includes: a third capacitor and a rectifying energy storage unit;

[0039] One end of the third capacitor is connected to the first connection end of the receiving coil of the magnetic coupler, and the other end of the third capacitor is connected to the first input end of the rectifier energy storage unit;

[0040] The second input end of the rectifying energy storage unit is connected to the second connection end of the receiving coil of the magnetic coupler.

[0041] As a possible implementation, the rectification and energy storage unit includes: a rectification unit, a filtering unit and an energy storage unit;

[0042] The first input end of the rectifier unit is connected to the other end of the third capacitor, and the second input end of the rectifier unit is connected to the second connection end of the receiving coil of the magnetic coupler;

[0043] The first output end of the rectifier unit is connected to one end of the filter unit, and the second output end of the rectifier unit is connected to the other end of the filter unit;

[0044] One end of the filter unit is also connected to the positive electrode of the energy storage unit, and the other end of the filter unit is connected to the negative electrode of the energy storage unit.

[0045] The beneficial effects of the present application include at least: the first transmitting coil and the second transmitting coil are coaxially arranged and wound in the same direction using Litz wire, so that the first transmitting coil and the second transmitting coil can be connected in series, ensuring that the magnetic coupler is axially resistant to offset, thereby reducing the impact of offset on the coupling performance of the magnetic coupler. In addition, the first transmitting coil and the second transmitting coil are superimposed to form a charging area during operation. The receiving coil of the magnetic coupler is placed in the charging area formed by the first transmitting coil and the second transmitting coil, thereby ensuring the coupling capability of the magnetic coupler and achieving effective coupling of the magnetic coupler. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0047] FIG1 is a schematic diagram of an exemplary scenario of a magnetic coupler and a wireless charging system provided in some embodiments of the present application;

[0048] FIG2 is a schematic structural diagram of a magnetic coupler in operation according to some embodiments of the present application;

[0049] FIG3 is another structural schematic diagram of a magnetic coupler in operation according to some embodiments of the present application;

[0050] FIG4 is an analytical model of a magnetic coupler provided in some embodiments of the present application;

[0051] FIG5 is another structural schematic diagram of a magnetic coupler in operation according to some embodiments of the present application;

[0052] Figure 6 is a schematic diagram of the magnetic field distribution of the transmitting coil;

[0053] FIG7 is another structural schematic diagram of a magnetic coupler in operation according to some embodiments of the present application;

[0054] FIG8 is a schematic structural diagram of a wireless charging system provided by some embodiments of the present application;

[0055] FIG9 is a schematic structural diagram of a transmitting device of a wireless charging system provided in some embodiments of the present application;

[0056] FIG10 is a schematic structural diagram of a transmitting device of a wireless charging system provided in some embodiments of the present application;

[0057] FIG11 is a schematic structural diagram of a transmitting device of a wireless charging system provided in some embodiments of the present application;

[0058] FIG12 is an equivalent circuit model of a wireless charging system;

[0059] FIG13 is a schematic structural diagram of a receiving device of a wireless charging system provided in some embodiments of the present application;

[0060] FIG14 is a schematic structural diagram of a rectifying energy storage unit in a receiving device of a wireless charging system provided in some embodiments of the present application.

[0061] In the figure: 201 - first transmitting coil; 202 - second transmitting coil; 203 - Litz wire; 204 - receiving coil; 205 - fixing member. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of illustration and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can be implemented out of sequence, and steps without logical context can be reversed or implemented simultaneously. In addition, those skilled in the art, under the guidance of the contents of this application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0063] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0064] It should be noted that the term "comprising" will be used in the embodiments of the present application to indicate the existence of the features declared thereafter, but does not exclude the addition of other features.

[0065] Magnetic couplers typically use circular or rectangular transmitting and receiving coils. These coils need to be aligned during operation to establish an inductive link when the magnetic coupler is powered on. These couplers are used in wireless charging systems for underwater vehicles and docking stations to charge the underwater vehicles. However, this magnetic coupler design is susceptible to variations in the size of the underwater vehicle and underwater natural phenomena, which can cause the magnetic coupler to deviate, reducing the wireless charging power and efficiency, and ultimately, the reliability of the wireless charging system for the underwater vehicle and docking station.

[0066] Based on the above-mentioned problems, the embodiments of the present application propose a magnetic coupler and a wireless charging system. By performing parameter analysis and structural design on the magnetic coupler, the influence of the magnetic coupler offset on the charging power and charging efficiency of the magnetic coupler is reduced. The magnetic coupler proposed in the present application can provide a stable coupling coefficient under offset conditions, thereby ensuring the charging power and charging efficiency of the underwater wireless charging system.

[0067] First, the application scenarios of the magnetic coupler and wireless charging system provided in the embodiments of the present application are described.

[0068] FIG1 is a schematic diagram of an exemplary scenario of a magnetic coupler and wireless charging system provided in some embodiments of the present application. Referring to FIG1 , the scenario may involve an underwater docking station and an autonomous underwater vehicle (AUV). The number of underwater docking stations can be multiple and can be selected based on the actual application scenario. The number of autonomous underwater vehicles can also be multiple and can be selected based on the actual application scenario. FIG1 illustrates one underwater docking station and one autonomous underwater vehicle as an example.

[0069] It should be understood that the magnetic coupler and wireless charging system provided in the embodiments of the present application are used to charge an autonomous underwater vehicle, particularly in scenarios where the autonomous underwater vehicle is charged using an underwater docking station. Generally, the underwater docking station and the autonomous underwater vehicle operate independently. When the autonomous underwater vehicle needs to be charged, the autonomous underwater vehicle can be brought into contact with the underwater docking station. Optionally, the autonomous underwater vehicle can be embedded in a recess provided in the underwater docking station to charge the autonomous underwater vehicle using the magnetic coupler and wireless charging system provided in the embodiments of the present application.

[0070] The magnetic coupler and wireless charging system provided in the embodiments of the present application are described in detail below in conjunction with multiple embodiments.

[0071] FIG2 is a schematic structural diagram of a magnetic coupler in operation according to some embodiments of the present application. Referring to FIG2 , the magnetic coupler 200 includes a first transmitting coil 201 , a second transmitting coil 202 , a Litz wire 203 , and a receiving coil 204 .

[0072] It should be understood that the first transmitting coil 201 and the second transmitting coil 202 of the magnetic coupler 200 are wound in the underwater dock, and the receiving coil 204 of the magnetic coupler 200 is embedded in the interior of the autonomous underwater vehicle.

[0073] Optionally, as shown in FIG2 , the first transmitting coil 201 and the second transmitting coil 202 may be toroidal coils, wound with Litz wire 203 so that the first transmitting coil 201 and the second transmitting coil 202 are connected in series from a circuit perspective. Furthermore, the receiving coil 204 may be a circular coil disposed between the first transmitting coil 201 and the second transmitting coil 202 to receive the magnetic flux generated by the first transmitting coil 201 and the second transmitting coil 202.

[0074] The first transmitting coil 201 and the second transmitting coil 202 are coaxially arranged.

[0075] Optionally, when the first transmitting coil 201 and the second transmitting coil 202 are annular coils, the centers of the first transmitting coil 201 and the second transmitting coil 202 are coaxially arranged, and the first transmitting coil 201 and the second transmitting coil 202 are arranged in parallel, so that the first transmitting coil 201 and the second transmitting coil 202 are symmetrical around the axis.

[0076] In this embodiment, since offset is difficult to avoid during operation of the magnetic coupler, in order to prevent the influence of the offset on the coupling performance of the magnetic coupler, the first transmitting coil and the second transmitting coil of the magnetic coupler are coaxially arranged. This ensures that the magnetic coupler is resistant to offset in the axial direction, thereby reducing the influence of the offset on the coupling performance of the magnetic coupler.

[0077] The Litz wire 203 is wound around the first transmitting coil 201 and the second transmitting coil 202 and connects the first transmitting coil 201 and the second transmitting coil 202 .

[0078] Optionally, when the first transmitting coil 201 and the second transmitting coil 202 are annular coils, the first transmitting coil 201 and the second transmitting coil 202 are wound with Litz wire 203 so that the first transmitting coil 201 and the second transmitting coil 202 are connected in series from a circuit perspective. On this basis, the Litz wire 203 is wound around the first transmitting coil 201 and the second transmitting coil 202 in the same direction so that the directions of the magnetic fields generated by the magnetic coupler 200 during operation are consistent.

[0079] For example, the magnetic field generated by the magnetic coupler provided in the embodiment of the present application is described. It should be understood that based on Faraday's law, the electromotive force ε is caused by the change of the magnetic flux φ passing through the circular coil, and the magnetic flux φ is generated by the magnetic field B, which can be described using the following formula (1) and formula (2):

[0080] Where A is the area enclosed by the coil. Because the first and second transmitting coils are connected in series and wound in the same direction, the two magnetic fields superimpose to form an AC magnetic field. This AC magnetic field creates inductance, enabling radio transmission.

[0081] When the magnetic coupler is working, the receiving coil 204 is located in the magnetic field formed by the first transmitting coil 201 and the second transmitting coil 202, and is coaxial with the first transmitting coil 201 and the second transmitting coil 202. The radius of the receiving coil 204 is smaller than the radius of the first transmitting coil 201, and the radius of the receiving coil 204 is smaller than the radius of the second transmitting coil 202.

[0082] Optionally, when the magnetic coupler 200 is in operation, a magnetic field is generated by the first transmitting coil 201 and the second transmitting coil 202 and encompasses the cylindrical region formed by the first transmitting coil 201 and the second transmitting coil 202, i.e., the charging region of the magnetic coupler 200. Simultaneously, the receiving coil 204 is positioned within the charging region, thereby achieving effective coupling and stable charging of the magnetic coupler 200 within the charging region. Furthermore, the receiving coil 204, the first transmitting coil 201, and the second transmitting coil 202 are coaxially arranged, and the radius of the receiving coil 204 is smaller than the radius of the first transmitting coil 201 and the second transmitting coil 202, thereby ensuring that the receiving coil 204 receives more magnetic flux.

[0083] In this embodiment, the first transmitting coil and the second transmitting coil are coaxially arranged and wound in the same direction using Litz wire. This allows the first transmitting coil and the second transmitting coil to be connected in series, ensuring that the magnetic coupler is resistant to axial misalignment, thereby reducing the impact of misalignment on the coupling performance of the magnetic coupler. Furthermore, during operation, the first transmitting coil and the second transmitting coil are superimposed to form a charging area. The receiving coil of the magnetic coupler is placed in the charging area formed by the first transmitting coil and the second transmitting coil, thereby ensuring the coupling capability of the magnetic coupler and achieving effective coupling of the magnetic coupler.

[0084] FIG3 is another structural schematic diagram of the magnetic coupler provided in an embodiment of the present application when in operation.

[0085] As a possible implementation, based on FIG2 , as shown in FIG3 , the radius of the first transmitting coil 201 is the same as the radius of the second transmitting coil 202 , and the straight-line distance between the center of the first transmitting coil 201 and the center of the second transmitting coil 202 is the same as the radius of the first transmitting coil 201 or the radius of the second transmitting coil 202 .

[0086] Optionally, when the first transmitting coil 201 and the second transmitting coil 202 are circular coils, they may be circular coils with the same radius, and the first transmitting coil 201 and the second transmitting coil 202 may be parallel circular coils with coaxial centers. In this regard, the straight-line distance between the centers of the first transmitting coil 201 and the second transmitting coil 202, i.e., the separation distance between the transmitting coils, may be the same as the radius of the first transmitting coil 201 or the radius of the second transmitting coil 202.

[0087] The following describes the transmission coil separation distance, the first transmission coil radius, and the second transmission coil radius in the above embodiment.

[0088] First, Figure 4 shows an analytical model of a magnetic coupler provided in an embodiment of the present application. Referring to Figure 3 , the first transmitting coil TX1 and the second transmitting coil TX2 of the magnetic coupler can be considered identical transmitting coils, sharing the same parameters. On this basis, X represents the position of the receiving coil. X = 0 means the receiving coil is at the midpoint between the first and second transmitting coils, meaning the first and second transmitting coils of the magnetic coupler are completely symmetrical relative to the receiving coil. X1 represents the distance between the receiving coil and the first transmitting coil, and X2 represents the distance between the receiving coil and the second transmitting coil. N represents the number of turns of the first and second transmitting coils, and n represents the number of turns of the receiving coil. Other parameters related to the magnetic coupler are shown in the following table:

[0089] It should be understood that in practical applications, the outer diameter of the receiving coil r out The coil radius R of the first and second transmitting coils is typically determined by the autonomous underwater vehicle and docking station. The coil lengths L of the first and second transmitting coils are typically determined by the number of turns N and the diameter of the Litz wire. It can be seen that the magnetic field strength and charging area of ​​the magnetic coupler need to be adjusted by the distance D between the first and second transmitting coils. Based on this, the coupling coefficient of the magnetic coupler and the distance D between the first and second transmitting coils are analyzed as follows:

[0090] The coupling coefficient k of the magnetic coupler can be expressed as formula (3):

[0091] Among them, L t is the self-inductance of the first transmitting coil and the second transmitting coil, L r is the self-inductance of the receiving coil, and M is the mutual inductance of the magnetic coupler.

[0092] Magnetic field strength of the first transmitting coil and the second transmitting coil It can be expressed as in is the magnetic field generated by the first transmitting coil, is the magnetic field generated by the second transmitting coil. When only the X component is considered, It can be expressed as:

[0093] Wherein, I is the current on the first transmitting coil and the second transmitting coil.

[0094] It should be understood that the mutual inductance M of the magnetic coupler is proportional to the magnetic field generated by the first transmitting coil and the second transmitting coil. Therefore, in order to ensure a stable magnetic field in the charging area, it is necessary to ensure that the magnetic field strength caused by the position X of the receiving coil is The change is the smallest, that is, the position X of the receiving coil and the magnetic field strength The following relationship needs to be satisfied:

[0095] When the position X of the receiving coil and the magnetic field strength When the above formula (6) is satisfied, the change of the magnetic field in the charging area can be minimized, thereby minimizing the impact of the axial offset on the magnetic field.

[0096] Based on this, the above formula (6) is solved to determine that the optimal transmitting coil separation distance D is approximately equal to the first transmitting coil radius and the second transmitting coil radius R. That is, when the distance between the first transmitting coil and the second transmitting coil is equal to the first transmitting coil radius and the second transmitting coil radius R, a uniform magnetic field can be generated in the charging area, so that the coupling coefficient k of the magnetic coupler provided in the embodiment of the present application remains constant.

[0097] In this embodiment, by determining the positions of the first transmitting coil, the second transmitting coil, and the receiving coil, the magnetic coupler provided in the embodiment of the present application can reduce fluctuations in the coupling coefficient in the charging region under offset conditions, thereby generating a uniform and stable magnetic field in the charging region of the magnetic coupler, ensuring the coupling capability of the magnetic coupler and achieving effective coupling of the magnetic coupler.

[0098] The above describes the transmitting coil separation distance, the first transmitting coil radius, and the second transmitting coil radius provided in the embodiments of the present application. Based on these transmission coil separation distances, the first transmitting coil radius, and the second transmitting coil radius, the mutual inductance M of the magnetic coupler is determined and described below.

[0099] It should be understood that in a wireless power transmission system, in order to achieve high transmission efficiency, it is generally necessary to compensate for the mutual inductance M. Therefore, it is necessary to determine the mutual inductance M of the magnetic coupler. Continuing with FIG. 3 , for example, the first transmitting coil and the second transmitting coil are simplified to two sets of hollow solenoids. Based on this, the mutual inductance M of the magnetic coupler can be estimated as:

[0100] in, is the mutual inductance between the first transmitting coil TX1 and the receiving coil, M is the mutual inductance between the second transmitting coil TX2 and the receiving coil. ij It can be calculated using the following formula (8):

[0101] in, β=(r in +r out ) / 2h, γ=R / h, μ0 is the vacuum permeability,

[0102] FIG5 is another structural schematic diagram of the magnetic coupler provided in an embodiment of the present application when in operation.

[0103] As a possible implementation, based on FIG2 , referring to FIG5 , guide ferrites are respectively provided on the inner wall of the first transmitting coil 201 and the inner wall of the second transmitting coil 202 .

[0104] It should be understood that when the first and second transmitting coils are in operation, alternating current is required to excite them, thereby generating magnetic fields on the outer and inner surfaces of the first and second transmitting coils. When the receiving coil is nested within the first or second transmitting coil, the magnetic coupler's coupling coefficient k increases due to the position of the receiving coils. In other words, the coupling coefficient k of the magnetic coupler in this case fluctuates compared to the coupling coefficient k of the magnetic coupler in the above-described embodiment. This affects the magnetic field strength and charging area of ​​the magnetic coupler. Therefore, guide ferrites are provided on the inner walls of the first and second transmitting coils to weaken the magnetic field, ensuring a stable coupling coefficient k of the magnetic coupler, thereby maintaining the coupling capability and achieving effective coupling.

[0105] For example, Figure 6 is a schematic diagram of the magnetic field distribution of the transmitting coil. The left figure in Figure 6 shows the magnetic field distribution when no guide ferrite is installed on the inner wall of the transmitting coil, and the right figure in Figure 6 shows the magnetic field distribution when the guide ferrite is installed on the inner wall of the transmitting coil. As shown in Figure 6, it can be seen that when the guide ferrite is installed on the inner wall of the transmitting coil, the magnetic field on the inner wall of the transmitting coil is significantly reduced.

[0106] In this embodiment, by providing guide ferrites on the inner walls of the first transmitting coil and the second transmitting coil, the magnetic field on the inner walls of the transmitting coils can be weakened, thereby ensuring the stability of the coupling coefficient k of the magnetic coupler, thereby ensuring the coupling capability of the magnetic coupler and achieving effective coupling of the magnetic coupler.

[0107] FIG7 is another structural schematic diagram of the magnetic coupler provided in some embodiments of the present application during operation.

[0108] As a possible implementation, based on FIG2 , referring to FIG7 , the magnetic coupler 200 further includes: a cylindrical fixing member 205;

[0109] The first transmitting coil 201 and the second transmitting coil 202 are sleeved on both ends of the fixing member 205 along the axial direction of the fixing member 205 .

[0110] Optionally, the magnetic coupler may further include a cylindrical fixing member 205, and the first transmitting coil 201 and the second transmitting coil 202 are axially sleeved on both ends of the fixing member 205 so that the first transmitting coil and the second transmitting coil remain coaxial. At the same time, there may be an opening on the fixing member 205 for placing the receiving coil.

[0111] Based on the same inventive concept, a wireless charging system is also provided in an embodiment of the present application. FIG8 is a structural schematic diagram of the wireless charging system provided in an embodiment of the present application. Based on FIG2 , referring to FIG8 , the wireless charging system includes: a transmitting device, a receiving device, and the above-mentioned magnetic coupler.

[0112] The first output end of the transmitting device is connected to one end of the Litz wire of the magnetic coupler, and the second output end of the transmitting device is connected to the other end of the Litz wire of the magnetic coupler.

[0113] It should be understood that the transmitting device can be set in the above-mentioned underwater docking station to provide current to the magnetic coupler to meet the charging needs of the magnetic coupler.

[0114] Optionally, the first output end of the transmitting device is electrically connected to one end of the Litz wire of the magnetic coupler, and the second output end of the transmitting device is electrically connected to the other end of the Litz wire of the magnetic coupler, so that the two ends of the Litz wire are respectively electrically connected to the transmitting device, so that under the current excitation of the transmitting device, a magnetic field is generated to charge the magnetic coupler.

[0115] The first connection end of the receiving coil is connected to the first input end of the receiving device, and the second connection end of the receiving coil is connected to the second input end of the receiving device.

[0116] It should be understood that the receiving device can be provided in the above-mentioned autonomous underwater vehicle to receive and store the electrical energy obtained by charging the magnetic coupler to meet the application requirements of the autonomous underwater vehicle.

[0117] Optionally, the receiving coil has a first connection end and a second connection end that form a loop with the receiving device. The first connection end of the receiving coil is electrically connected to the first input end of the receiving device, and the second connection end of the receiving coil is electrically connected to the second input end of the receiving device, so that the two ends of the receiving coil are respectively connected to the receiving device, and the electric energy obtained by charging the magnetic coupler is received and stored for subsequent power supply of the autonomous underwater vehicle.

[0118] In this embodiment, by providing a transmitting device and a receiving device, the characteristics and performance of the magnetic coupler can be verified, and the requirements for underwater wireless charging can be met in practical applications.

[0119] The specific structure of the transmitting device is described below. FIG9 is a schematic diagram of the structure of the transmitting device of the wireless charging system provided in an embodiment of the present application.

[0120] As a possible implementation, based on FIG8 , referring to FIG9 , the transmitting device includes: a DC power supply, an inverter unit, and a resonance unit.

[0121] It should be understood that in the transmitting device, the DC power supply is used to provide a stable power output for the transmitting device, the inverter unit is used to convert DC power into AC power, and the resonance unit is used to perform constant processing on the AC power converted by the inverter unit, so that the output current of the transmitting device is independent of the load of the transmitting device, thereby meeting the requirements of wireless charging of the magnetic coupler.

[0122] The positive electrode of the DC power supply is connected to the first input terminal and the second input terminal of the inverter unit, and the negative electrode of the DC power supply is connected to the third input terminal and the fourth input terminal of the inverter unit.

[0123] Optionally, the positive and negative poles of the DC power supply are electrically connected to the inverter unit, the positive pole of the DC power supply is electrically connected to the first input terminal and the second input terminal of the inverter unit, and the negative pole of the DC power supply is electrically connected to the third input terminal and the fourth input terminal of the inverter unit.

[0124] The first output terminal and the second output terminal of the inverter unit are connected to the input terminal of the resonance unit.

[0125] Optionally, the inverter unit is electrically connected to the DC power supply and the resonance unit, respectively. The first input terminal and the second input terminal of the inverter unit are electrically connected to the positive electrode of the DC power supply, the third input terminal and the fourth input terminal of the inverter unit are electrically connected to the negative electrode of the DC power supply, and the first output terminal and the second output terminal of the inverter are connected to the input terminal of the resonance unit.

[0126] The first output end of the resonance unit is connected to one end of the Litz wire of the magnetic coupler, and the second output end of the resonance unit is connected to the other end of the Litz wire of the magnetic coupler.

[0127] Optionally, the resonance unit is electrically connected to the inverter unit and the Litz wire of the magnetic coupler, respectively. The input end of the resonance unit is electrically connected to the first output end and the second output end of the inverter, the first output end of the resonance unit is electrically connected to one end of the Litz wire of the magnetic coupler, and the second output end of the resonance unit is electrically connected to the other end of the Litz wire of the magnetic coupler.

[0128] In this embodiment, a DC power supply, an inverter unit, and a resonance unit are provided in the transmitting device to connect the transmitting device and the first transmitting coil and the second transmitting coil of the magnetic coupler to form a loop. This enables current excitation to generate a magnetic field in the magnetic coupler, thereby charging the magnetic coupler.

[0129] The specific structure of the inverter unit in the transmitting device is described below. FIG10 is a schematic structural diagram of the transmitting device of the wireless charging system provided in an embodiment of the present application.

[0130] As a possible implementation, based on FIG9 , referring to FIG10 , the inverter unit includes: a first field effect transistor S1 , a second field effect transistor S2 , a third field effect transistor S3 and a fourth field effect transistor S4 .

[0131] It should be understood that the inverter unit composed of four field effect transistors can rectify and convert direct current into alternating current.

[0132] The drain of the first field effect transistor S1 and the drain of the third field effect transistor S3 are connected to the positive electrode of the DC power supply, the source of the first field effect transistor S1 is connected to the drain of the second field effect transistor S2, and the source of the second field effect transistor S2 is connected to the negative electrode of the DC power supply.

[0133] The source of the third field effect transistor S3 is connected to the drain of the fourth field effect transistor S4 , and the source of the fourth field effect transistor S4 is connected to the negative electrode of the DC power supply.

[0134] The source of the first field effect transistor S1 is also connected to the first input terminal of the resonance unit.

[0135] The source of the third field effect transistor S3 is also connected to the second input terminal of the resonance unit.

[0136] In this embodiment, a single-phase full-bridge inverter unit is formed by four field effect transistors, and the process of converting direct current into alternating current is modulated separately to input into the resonance unit.

[0137] The specific structure of the resonance unit in the transmitting device is described below. FIG11 is a schematic structural diagram of the transmitting device of the wireless charging system provided in an embodiment of the present application.

[0138] As a possible implementation, based on FIG9 , referring to FIG11 , the resonant unit includes: an inductor L in , the first capacitor C s1 and the second capacitor C p1 .

[0139] It should be understood that the resonant unit adopts the LCC-S compensation topology design, which enables the transmitter to have a constant current source, providing a load-independent current to meet the requirements of battery charging applications. At the same time, the additional inductor in the LCC-S compensation topology provides additional design freedom for the wireless charging system, enhancing its flexibility.

[0140] On this basis, the wireless charging system can be equivalent to obtain the equivalent circuit model of the wireless charging system, referring to Figure 12. Figure 12 is the equivalent circuit model of the wireless charging system, where the T model is used to analyze the behavior of the magnetic coupler, and the parameters on the receiving device side are referred to as the transmitting device side. Since the coil resistance usually does not affect the resonant condition of the system, the resistance of the first transmitting coil, the second transmitting coil and the receiving coil of the magnetic coupler are ignored in Figure 12, and only the resonant condition of the topological structure is concerned. The lowercase symbols in Figure 12 represent the root mean square value of the fundamental component of the corresponding signal. a is the turns ratio of the magnetic coupler, and the calculation formula is: a=(L t / L r ) 0.5 . r o Is the equivalent AC load resistance after rectification. Magnetizing inductance L m and leakage reactance L t '、L r ' can be expressed as: L m =aM,L′ t =L t -L m , L′ r =a 2 L r -L m (8)

[0141] At the resonant frequency ω s Next, L in with C s1 A part of the current resonates and forms a constant current source (expressed as i v-c ):

[0142] The receiving coil current can be compared with the transmitting coil current i p Related: p =i v-c =i s / a. In order to achieve zero phase angle (ZPA) on the receiving coil side, a -2 C s2 Designed to compensate for L r ' and the reactive current generated by formula (9). Therefore, ω s The resonance conditions can be summarized as:

[0143] The current gain of the compensation topology can be determined as:

[0144] The average output current and voltage can be expressed as:

[0145] According to the above derivation, L in , C p1 , C s1 , C s2 Based on this, it can be calculated as:

[0146] Inductor L in One end of the inductor is connected to the first output end of the inverter unit, and the inductor L in The other end of the first capacitor C s1 One end of the second capacitor C p1 one end of the .

[0147] Optional, inductor L in As an additional inductor in the LCC-S compensation topology, it provides additional design freedom for the wireless charging system and enhances the flexibility of the wireless charging system. in One end of the inductor is electrically connected to the first output end of the inverter unit, and the inductor L in The other end of the first capacitor C s1 One end of the second capacitor C p1 One end is electrically connected.

[0148] The first capacitor C s1 The other end is connected to the second output end of the inverter unit and one end of the Litz wire of the magnetic coupler.

[0149] Optionally, the first capacitor C s1 The other end is electrically connected to the second output end of the inverter unit and one end of the Litz wire of the magnetic coupler.

[0150] The second capacitor C p1 The other end of the magnetic coupler is connected to the other end of the Litz wire.

[0151] Optionally, the second capacitor C p1 The other end of the magnetic coupler is electrically connected to the other end of the Litz wire

[0152] The specific structure of the receiving device is described below. FIG13 is a schematic diagram of the structure of the receiving device of the wireless charging system provided in an embodiment of the present application.

[0153] As a possible implementation, based on FIG8 , referring to FIG13 , the receiving device includes: a third capacitor and a rectifying energy storage unit.

[0154] Optionally, a third capacitor is used to connect the rectifying energy storage unit and the receiving coil of the magnetic coupler, thereby avoiding cross coupling between the magnetic coupler and the rectifying energy storage unit.

[0155] Optionally, the rectifying energy storage unit rectifies and stores the electric energy received by the receiving coil of the magnetic coupler to meet subsequent use.

[0156] One end of the third capacitor is connected to the first connection end of the receiving coil of the magnetic coupler, and the other end of the third capacitor is connected to the first input end of the rectifying energy storage unit.

[0157] Optionally, one end of the third capacitor is electrically connected to the first connection end of the receiving coil of the magnetic coupler, and the other end of the third capacitor is electrically connected to the first input end of the rectifier energy storage unit.

[0158] The second input end of the rectifying energy storage unit is connected to the second connection end of the receiving coil of the magnetic coupler.

[0159] Optionally, the second input end of the rectifying energy storage unit is electrically connected to the second connection end of the receiving coil of the magnetic coupler.

[0160] The specific structure of the rectifying energy storage unit in the receiving device is described below. FIG14 is a schematic diagram of the structure of the rectifying energy storage unit in the receiving device of the wireless charging system provided in an embodiment of the present application.

[0161] As a possible implementation, based on FIG13 , referring to FIG14 , the rectification and energy storage unit includes: a rectification unit, a filtering unit, and an energy storage unit.

[0162] Optionally, the rectifying unit rectifies the electric energy received by the receiving coil of the magnetic coupler, and the filtering unit filters the electric energy rectified by the rectifying unit, and the electric energy is stored by the energy storage unit for subsequent use.

[0163] The first input end of the rectifier unit is connected to the other end of the third capacitor, and the second input end of the rectifier unit is connected to the second connection end of the receiving coil of the magnetic coupler.

[0164] The first output end of the rectifier unit is connected to one end of the filter unit, and the second output end of the rectifier unit is connected to the other end of the filter unit.

[0165] Optionally, the rectifier unit can be a rectifier unit composed of four diodes, the first input end of the rectifier unit is electrically connected to the other end of the third capacitor, the second input end of the rectifier unit is electrically connected to the second connection end of the receiving coil of the magnetic coupler, the first output end of the rectifier unit is electrically connected to one end of the filter unit, and the second output end of the rectifier unit is electrically connected to the other end of the filter unit.

[0166] One end of the filter unit is also connected to the positive electrode of the energy storage unit, and the other end of the filter unit is connected to the negative electrode of the energy storage unit.

[0167] Optionally, the filter unit may be a filter capacitor, one end of the filter capacitor is electrically connected to the positive electrode of the energy storage unit, and the other end of the filter capacitor is electrically connected to the negative electrode of the energy storage unit.

[0168] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system and device described above can refer to the corresponding process in the method embodiment, and will not be repeated in this application. In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0169] The above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the protection scope of the present application. Industrial Applicability

[0170] The present application provides a magnetic coupler and a wireless charging system. A first transmitting coil and a second transmitting coil are coaxially arranged and wound in the same direction using Litz wire. The first transmitting coil and the second transmitting coil can be connected in series, ensuring that the magnetic coupler is axially resistant to offset, thereby reducing the impact of offset on the coupling performance of the magnetic coupler. The first transmitting coil and the second transmitting coil are superimposed to form a charging area during operation. The receiving coil of the magnetic coupler is placed in the charging area formed by the first transmitting coil and the second transmitting coil, thereby ensuring the coupling capability of the magnetic coupler and achieving effective coupling of the magnetic coupler.

[0171] Furthermore, it is understood that the magnetic coupler and wireless charging system provided herein are reproducible and can be used in a variety of industrial applications. For example, the magnetic coupler and wireless charging system provided herein can be used in the field of wireless charging technology.

Claims

1. A magnetic coupler, characterized in that: The magnetic coupler comprises: a first transmitting coil, a second transmitting coil, a Litz wire and a receiving coil; The first transmitting coil and the second transmitting coil are coaxially arranged; The Litz wire is wound around the first transmitting coil and the second transmitting coil and connects the first transmitting coil and the second transmitting coil; When the magnetic coupler is working, the receiving coil is located in the magnetic field formed by the first transmitting coil and the second transmitting coil, and is coaxial with the first transmitting coil and the second transmitting coil, and the radius of the receiving coil is smaller than the radius of the first transmitting coil, and the radius of the receiving coil is smaller than the radius of the second transmitting coil.

2. The magnetic coupler according to claim 1, characterized in that The first transmitting coil and the second transmitting coil are wound in an underwater docking station, and the receiving coil is embedded in the interior of the autonomous underwater vehicle.

3. The magnetic coupler according to claim 1 or 2, characterized in that: The first transmitting coil and the second transmitting coil are both annular coils, and the Litz wire is configured to be wound around the first transmitting coil and the second transmitting coil in the same direction, so that the magnetic field generated by the magnetic coupler during operation has the same direction.

4. The magnetic coupler according to any one of claims 1 to 3, characterized in that: The radius of the first transmitting coil is the same as the radius of the second transmitting coil, and a straight-line distance between the center of the first transmitting coil and the center of the second transmitting coil is the same as the radius of the first transmitting coil or the radius of the second transmitting coil.

5. The magnetic coupler according to any one of claims 1 to 4, characterized in that: Guide ferrites are respectively arranged on the inner wall of the first transmitting coil and the inner wall of the second transmitting coil.

6. The magnetic coupler according to any one of claims 1 to 5, characterized in that: The magnetic coupler further comprises: a cylindrical fixing member; The first transmitting coil and the second transmitting coil are sleeved at two ends of the fixing member along the axial direction of the fixing member.

7. The magnetic coupler according to claim 6, characterized in that: The fixing member is provided with an opening for placing the receiving coil.

8. A wireless charging system, characterized in that: include: A transmitting device, a receiving device, and a magnetic coupler according to any one of claims 1 to 7; The first output end of the transmitting device is connected to one end of the Litz wire of the magnetic coupler, and the second output end of the transmitting device is connected to the other end of the Litz wire of the magnetic coupler; The first connection end of the receiving coil is connected to the first input end of the receiving device, and the second connection end of the receiving coil is connected to the second input end of the receiving device.

9. The wireless charging system according to claim 8, characterized in that: The transmitting device is arranged in an underwater docking station, and the receiving device is arranged in an autonomous underwater vehicle.

10. The wireless charging system according to claim 8 or 9, characterized in that: The transmitting device comprises: a DC power supply, an inverter unit and a resonance unit; The positive electrode of the DC power supply is connected to the first input terminal and the second input terminal of the inverter unit, and the negative electrode of the DC power supply is connected to the third input terminal and the fourth input terminal of the inverter unit; The first output terminal and the second output terminal of the inverter unit are connected to the input terminal of the resonance unit; The first output end of the resonance unit is connected to one end of the Litz wire of the magnetic coupler, and the second output end of the resonance unit is connected to the other end of the Litz wire of the magnetic coupler.

11. The wireless charging system according to claim 10, characterized in that: The inverter unit includes: a first field effect transistor, a second field effect transistor, a third field effect transistor and a fourth field effect transistor; The drain of the first field effect transistor and the drain of the third field effect transistor are connected to the positive electrode of the DC power supply, the source of the first field effect transistor is connected to the drain of the second field effect transistor, and the source of the second field effect transistor is connected to the negative electrode of the DC power supply; The source of the third field effect transistor is connected to the drain of the fourth field effect transistor, and the source of the fourth field effect transistor is connected to the negative electrode of the DC power supply; The source of the first field effect transistor is also connected to the first input terminal of the resonance unit; The source of the third field effect transistor is also connected to the second input end of the resonance unit.

12. The wireless charging system according to claim 10 or 11, characterized in that: The resonance unit includes: an inductor, a first capacitor and a second capacitor; One end of the inductor is connected to the first output end of the inverter unit, and the other end of the inductor is connected to one end of the first capacitor and one end of the second capacitor; The other end of the first capacitor is connected to the second output end of the inverter unit and one end of the Litz wire of the magnetic coupler; The other end of the second capacitor is connected to the other end of the Litz wire of the magnetic coupler.

13. The wireless charging system according to any one of claims 8 to 12, characterized in that: The receiving device comprises: a third capacitor and a rectifying energy storage unit; One end of the third capacitor is connected to the first connection end of the receiving coil of the magnetic coupler, and the other end of the third capacitor is connected to the first input end of the rectifying energy storage unit; The second input end of the rectifying energy storage unit is connected to the second connection end of the receiving coil of the magnetic coupler.

14. The wireless charging system according to claim 13, characterized in that: The rectification and energy storage unit comprises: a rectification unit, a filtering unit and an energy storage unit; The first input terminal of the rectifier unit is connected to the other end of the third capacitor, and the second input terminal of the rectifier unit is connected to the other end of the third capacitor. The end is connected to the second connection end of the receiving coil of the magnetic coupler; The first output end of the rectifying unit is connected to one end of the filtering unit, and the second output end of the rectifying unit is connected to the other end of the filtering unit; One end of the filter unit is also connected to the positive electrode of the energy storage unit, and the other end of the filter unit is connected to the negative electrode of the energy storage unit.

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