Wireless power transmission equipment with metal interference resistant structure

Abstract

The invention relates to the technical field of wireless transmission, and discloses a wireless electric energy transmission device of a metal interference resistant structure, which comprises a shell and a receiving coil, a main transmitting coil is connected in the shell, one side of the shell is connected with a mounting groove, and a main loop circuit and a detection unit are connected in the mounting groove. One side of the shell is connected with a degaussing coil, and the main loop circuit comprises an inverter, a power supply module and a control unit. The detection and degaussing circuit controls the degaussing coil to realize the detection and degaussing functions of the metal foreign matter, the main loop circuit and the degaussing system work cooperatively to ensure the stability and high efficiency of the system, the activated degaussing coil generates a reverse magnetic field near the metal foreign matter, the magnetic field intensity of the area is reduced, and the degaussing effect of the metal foreign matter is improved. And eddy current induced in the metal foreign matter is reduced, so that temperature rise is remarkably reduced, and potential safety hazards are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of wireless transmission, and in particular to a wireless power transmission device with an anti-metal interference structure. Background Art

[0002] Among the key components in the wireless power transmission system, the main transmitting coil (primary coil) generates an alternating current in the transmitter (charger), thereby generating a high-frequency magnetic field. The receiving coil (secondary coil) is located in the receiver (such as a smartphone or electric car). Through the principle of electromagnetic induction, the high-frequency magnetic field generated by the transmitting coil is converted back into electrical energy, which is then supplied to the load. This technology is widely used in various wireless charging devices, such as wireless chargers, wireless charging PADs, and some forms of electric vehicle wireless charging systems.

[0003] Wireless charging may indeed be interfered with by metal magnetic fields. Wireless charging technology is generally based on the principle of electromagnetic induction, in which the magnetic field between the transmitter (charger) and the receiver (device) is the key. Metal objects, especially magnetic materials such as iron, nickel and cobalt, may interfere with the magnetic field between the charger and the working device. If metal objects are located near the transmitter or receiver, they can absorb or distort the magnetic field, thereby reducing charging efficiency or completely preventing charging. If the transmitter or receiver is close to a metal surface, such as a metal table or kitchen countertop, the magnetic field may be reflected or short-circuited, which will also affect the charging effect. Any metal foreign objects between the transmitter and receiver may cause uneven distribution of the magnetic field, thereby affecting charging efficiency.

[0004] The above information disclosed in the background technology is only used to increase the understanding of the background technology of the present application, and therefore, it may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The object of the present invention is to provide a wireless power transmission device with a metal interference resistant structure to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solution: comprising a shell and a receiving coil, wherein a main transmitting coil is connected and arranged inside the shell, a mounting groove is connected and arranged on one side of the shell, and a main loop circuit and a detection unit are connected and arranged in the mounting groove, and a demagnetization coil is connected and arranged on one side of the shell.

[0007] Preferably, the main loop circuit includes an inverter, a transmitter compensation network, a transmitter coil, a receiver coil, a receiver compensation network, a rectifier bridge and a load.

[0008] Preferably, the detection unit includes a metal foreign matter detection module, a degaussing coil driving circuit and a controller.

[0009] Preferably, the degaussing coil is located above the main transmitting coil.

[0010] Preferably, the degaussing coil is produced using a genetic algorithm.

[0011] Preferably, the degaussing coil is a double-layer structure, and the corners of the degaussing coil are rounded.

[0012] Preferably, the main loop circuit adopts any topology including SS, LCC-S, LCC-LCC and other topologies.

[0013] Preferably, the degaussing coil can be arranged in a different layout, size and number of turns as required.

[0014] In summary, this application includes the following beneficial technical effects:

[0015] (1) The detection and degaussing circuit controls the degaussing coil to realize the detection and degaussing functions of metal foreign bodies. The main circuit and the degaussing system work together to ensure the stability and efficiency of the system. The activated degaussing coil generates a reverse magnetic field near the metal foreign body, reducing the magnetic field strength in the area and the eddy current induced in the metal foreign body, thereby significantly reducing its temperature rise and avoiding safety hazards;

[0016] (2) During the degaussing process, the energy transmission between the main transmitting coil and the receiving coil remains stable. Through precise control and design of the degaussing coil, the degaussing process has minimal impact on the power output and transmission efficiency of the main system. The degaussing coil has both detection and degaussing functions, saving hardware resources and improving the system integration.

[0017] (3) By scanning the degaussing coil array, the position of the metal foreign body can be accurately detected, providing a basis for subsequent degaussing control. According to the position of the metal foreign body, the degaussing coil is selectively activated, and a symmetrical compensation method is used to minimize the impact on the magnetic flux of the main system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of a wireless power transmission device with an anti-metal interference structure according to the present invention;

[0019] Figure 2 It is a schematic diagram of the distribution structure of the degaussing coil and the main transmitting coil in the present invention;

[0020] Figure 3 It is an exploded view between the degaussing coil and the main transmitting coil in the present invention;

[0021] Figure 4 A schematic diagram of the design mechanism of a degaussing coil in a wireless power transmission device with an anti-metal interference structure according to the present invention;

[0022] Figure 5 It is a structural schematic diagram of the double-layer degaussing coil in the present invention;

[0023] Figure 6 A schematic diagram of the circuit structure of a degaussing coil driving circuit in a wireless power transmission device with an anti-metal interference structure according to the present invention;

[0024] Figure 7 A schematic diagram of the module structure of a detection unit in a wireless power transmission device with an anti-metal interference structure according to the present invention;

[0025] Figure 8 A schematic diagram of a state module structure of a wireless power transmission device with an anti-metal interference structure according to the present invention detecting a metal foreign body;

[0026] Fig. 9 The present invention is a schematic diagram of the module structure of a wireless power transmission device with an anti-metal interference structure in a use state without metal foreign matter.

[0027] In the figure: 1. Shell; 2. Main transmitting coil; 3. Main loop circuit; 4. Detection unit; 51. Inverter; 52. Power module; 53. Control unit; 61. Metal foreign body detection module; 62. Degaussing coil drive circuit; 63. Controller; 7. Degaussing coil. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] See also Figure 1-9 The present invention provides a technical solution: including a shell 1 and a receiving coil, wherein a main transmitting coil 2 is connected and arranged inside the shell 1, and the main transmitting coil 2 is responsible for converting electrical energy into a high-frequency magnetic field. The receiving coil receives energy through magnetic field coupling and supplies it to the load. Its design needs to meet the requirements of high-power transmission and has high efficiency and stability. A mounting groove is connected and arranged on one side of the shell 1, and a main loop circuit 3 and a detection unit 4 are connected and arranged in the mounting groove. A degaussing coil 7 is connected and arranged on one side of the shell 1. The degaussing coil 7 is composed of a plurality of degaussing coils, which are arranged in an array form and cover the area of ​​the main transmitting coil 2. Figure 2 and Figure 3As shown, these degaussing coils also serve as metal foreign body detection coils. By scanning different coils, comprehensive monitoring and control of the transmitting area is achieved. The degaussing coil 7 array covers the top of the main transmitting coil 2 to form a multi-coil combination. The detection and degaussing circuit realizes the detection and degaussing functions of metal foreign bodies by controlling the degaussing coils. The main loop circuit 3 works in conjunction with the degaussing system to ensure the stability and efficiency of the system.

[0030] The degaussing coil 7 is designed using the following expression:

[0031]

[0032] Reference Figure 7 As shown, the main loop circuit 3 includes an inverter, a transmitter compensation network, a transmitter coil, a receiver coil, a receiver compensation network, a rectifier bridge and a load.

[0033] Reference Figure 8 The detection unit 4 includes a metal foreign body detection module 61, a degaussing coil driving circuit 62 and a controller 63. The metal foreign body detection module 61 monitors the magnetic field changes in each area in real time by scanning the degaussing coil array one by one. When a metal foreign body is detected, the controller 63 activates the corresponding degaussing coil 7 according to the position of the metal;

[0034] The degaussing circuit 62 is used to drive the degaussing coil 7 to cancel the magnetic field in a specific area. Each degaussing coil 7 is controlled by an independent driving circuit, which is convenient for realizing accurate control of different areas. The driving signal of the degaussing coil 7 needs to be accurately controlled in amplitude and phase with the current signal of the main transmitting coil 2 to achieve effective cancellation of the magnetic field. The power of the degaussing circuit should be sufficient to generate the required reverse magnetic field, but not too large to avoid energy waste. The output of the degaussing coil 7 can be controlled by adjusting the driving voltage and current.

[0035] The degaussing coil 7 is located above the main transmitting coil 2 so that it covers the entire energy transmission area. The arrangement of the coils needs to be coordinated with the magnetic field distribution of the main transmitting coil 2, with special attention paid to the magnetic field changes in the edge area of ​​the main coil. Figure 2-Figure 3 As shown in the figure, achieving a relatively uniform magnetic field distribution can effectively reduce the impact of the degaussing coil magnetic field on the system performance. For the centrally placed degaussing coil, the mutual inductance can be reduced by optimizing its geometric shape and winding method. In addition, the activation of the degaussing coil should try to maintain the original magnetic field distribution uniformity of the main transmitting coil, which can be ensured by symmetrical activation or by designing a reasonable current distribution.

[0036] The accompanying figure shows a schematic diagram of the relative position relationship between the degaussing coil 7 array and the main transmitting coil 2, from which it can be seen that the layout, shape and winding strategy of the degaussing coil 7 affect and regulate the magnetic field of the main transmitting coil. Coils of the same specifications are symmetrical coils. When it is necessary to offset the magnetic field in a certain area, the symmetrical area will generate an enhanced magnetic field of the same size.

[0037] The degaussing coil 7 is designed by using a genetic algorithm. When the degaussing coil is designed by using a genetic algorithm, a set of decision variables {d i}(i=2,…,n) to control the size change rule of each turn of the coil. The initial side length of the outermost coil is 2a0, and the side length of each turn of the coil is 2a i By decrementing the parameter {d i} obtain, that is, a i =a i-1 -d i-1 (i=2,…,n). In this way, during the optimization process, {d i}Determines the proportion and layout of the coil array as it gradually decreases from the outside to the inside;

[0038] In order to achieve the homogenization of the magnetic field in a given spatial region (x∈[-0.65a0,0.65a0],y∈[-0.65a0,0.65a0],z∈[3mm,8mm]), a corresponding objective function is defined as the optimization criterion. This objective function is used to measure the B z The uniformity of magnetic field distribution is usually in the form of B z The ratio of the maximum-minimum difference of the value distribution to the average value. The nonlinear constraint ensures that the size of each turn of the coil does not appear unreasonable during the calculation process. The genetic algorithm calculates the {d i}Perform iterative search, starting from a randomly initialized parameter set, through selection, crossover and mutation operations, to evolve a better parameter combination generation by generation. The optimization process calculates the corresponding magnetic field distribution in each generation, substitutes the calculation results into the objective function, identifies the parameter schemes that make the distribution more uniform, and tends to retain and improve these schemes. The final degaussing coil design scheme can generate a vertical component magnetic field as uniform as possible within the target three-dimensional range;

[0039] On this basis, according to the shape characteristics of the transmitting coil in practical applications, the final single-layer degaussing coil is appropriately modified in structure, and the corners of the coil are rounded to improve the effect after degaussing. In addition, in order to reduce the loss and further improve the overall performance under the premise of ensuring the uniformity of the magnetic field, the degaussing coil is designed into a double-layer structure, such as Figure 5 shown.

[0040] The degaussing coil 7 is a double-layer structure, and the corners of the coil are rounded;

[0041] In the above optimization steps, it is assumed that a single-layer coil generates the required Bsc field strength at a given point (x, y, z) and its power consumption is P sc =R sc I sc 2 When the coil structure is changed from a single layer to a double layer, if the resistance is doubled to 2R sc , and the current is reduced to 1 / 2 of the original value, that is, it becomes I sc / 2, the new power consumption P new It can be expressed as:

[0042]

[0043] Therefore, in order to ensure the same B sc Under the condition of magnetic field, by designing the coil as a double-layer structure and adjusting the corresponding parameters, the power consumption is effectively reduced to half of the original. In the final double-layer degaussing coil design, through appropriate rounded corner transition and parameter optimization, not only a good magnetic field uniformity is maintained in the target area, but also the conduction loss is significantly reduced compared with the single-layer solution, thus achieving a better balance in overall performance.

[0044] The main loop circuit 3 adopts any topology including SS, LCC-S, LCC-LCC, etc.:

[0045] The degaussing coil 7 can be changed in layout, size and number of turns as required;

[0046] Accurately calculate the component parameters of the degaussing circuit;

[0047] Demagnetization circuit parameter calculation:

[0048] Demagnetization current I d :Calculate the current of the degaussing coil according to the magnetic field strength that needs to be offset:

[0049]

[0050] Among them, B d is the magnetic field strength that needs to be offset, N d is the number of turns of the degaussing coil, A is the cross-sectional area of ​​the coil, and l is the length of the magnetic path.

[0051] Phase control: To achieve effective magnetic field cancellation, the phase of the degaussing coil current should be opposite to the main transmitting coil current. Precise control is achieved through the phase adjustment circuit.

[0052] System efficiency calculation:

[0053] Total efficiency η:

[0054]

[0055] Among them, P out is the power received by the receiving coil, P in = is the system input power.

[0056] Degaussing system power consumption: Calculate the power consumption P of the degaussing circuit d , and evaluate its impact on the overall efficiency to ensure that the power consumption of the degaussing system does not exceed 1%.

[0057]

[0058] Among them, R d is the equivalent resistance of the degaussing coil.

[0059] The implementation principle of the present application is as follows: in the absence of metal foreign matter, the main loop circuit drives the main transmitting coil to generate a high-frequency magnetic field, and the receiving coil receives energy through magnetic field coupling and supplies it to the load. At this time, the degaussing coil array is only used to detect metal foreign matter, and no degaussing operation is performed. The system operates at the highest efficiency. The detection module detects the magnetic field changes near each coil by scanning the degaussing coil array one by one. When a degaussing coil detects an abnormality (i.e., the magnetic field changes caused by metal foreign matter), the system determines the position of the metal foreign matter. According to the position of the metal foreign matter, the controller activates a specific degaussing coil. If the metal foreign matter is located in a non-central position, the degaussing coil above the metal foreign matter and another degaussing coil symmetrical with it about the central axis are activated. The mutual inductance of the two degaussing coils and the main transmitting coil cancels each other, generating a magnetic field opposite to the main magnetic field near the metal foreign matter. Magnetic field, reducing the magnetic field strength in this area. At the same time, the forward magnetic field generated by the symmetrical degaussing coil keeps the overall magnetic flux of the main system basically unchanged. If the metal foreign body is located in the center, only the central degaussing coil needs to be activated. Since the central degaussing coil is designed to have a very small mutual inductance with the main transmitting coil, the magnetic field it generates is mainly used to offset the main magnetic field in the central area and reduce the eddy currents in the metal foreign body. At the same time, the magnetic field in the peripheral area will increase appropriately, but the overall magnetic flux of the main system changes little, and the impact on energy transmission is limited. The activated degaussing coil generates a reverse magnetic field near the metal foreign body, reducing the magnetic field strength in this area and reducing the eddy currents induced in the metal foreign body, thereby significantly reducing its temperature rise and avoiding safety hazards. When the metal foreign body is removed, the detection module senses that the magnetic field has returned to normal, the controller turns off the corresponding degaussing coil, and the system returns to normal working mode.

[0060] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wireless power transmission device with an anti-metal interference structure, comprising a housing (1) and a receiving coil, characterized in that: A main transmitting coil (2) is connected and arranged inside the shell (1); a mounting groove is connected and arranged on one side of the shell (1); a main loop circuit (3) and a detection unit (4) are connected and arranged in the mounting groove; and a demagnetization coil (7) is connected and arranged on one side of the shell (1).

2. The wireless power transmission device with anti-metal interference structure according to claim 1, characterized in that: The main loop circuit (3) comprises an inverter, a transmitting end compensation network, a transmitting coil, a receiving coil, a receiving end compensation network, a rectifier bridge and a load.

3. The wireless power transmission device with anti-metal interference structure according to claim 1, characterized in that: The detection unit (4) comprises a metal foreign matter detection module (61), a degaussing coil driving circuit (62) and a controller (63).

4. The wireless power transmission device with anti-metal interference structure according to claim 1, characterized in that: The degaussing coil (7) is located above the main transmitting coil (2).

5. The wireless power transmission device with anti-metal interference structure according to claim 1, characterized in that: The degaussing coil (7) uses a genetic algorithm.

6. The wireless power transmission device with anti-metal interference structure according to claim 1, characterized in that: The degaussing coil (7) is a double-layer structure, and the corners of the degaussing coil are rounded.

7. The wireless power transmission device with anti-metal interference structure according to claim 1, characterized in that: The main loop circuit (3) adopts any topology including SS, LCC-S, LCC-LCC and other topologies.

8. The wireless power transmission device with anti-metal interference structure according to claim 1, characterized in that: The degaussing coil (7) can be arranged in a different layout, size and number of turns as required.

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