Magnetic coupling mechanism of wireless power transmission system and multi-mode thermal balance control method thereof

Abstract

The invention relates to the technical field of magnetic coupling wireless electric energy transmission, in particular to a magnetic coupling mechanism of a wireless electric energy transmission system and a multi-mode thermal balance control method thereof.The magnetic coupling mechanism comprises a magnetic energy emission structure which is composed of three fan-shaped coils of the same structure, and the three fan-shaped coils are arranged in parallel at equal intervals and evenly distributed in the circumferential direction around the same central axis; the three fan-shaped coils are arranged in parallel; the magnetic energy receiving structure is a square planar spiral coil which is arranged in parallel and opposite to the three fan-shaped coils; the water cooling device comprises three groups of fan-shaped heat dissipation coil pipes with the same structure; the three groups of fan-shaped heat dissipation coil pipes are in one-to-one correspondence with the three fan-shaped coils and are tightly adjacent to the three fan-shaped coils; and the plurality of temperature sensors are distributed on one surface, facing the fan-shaped heat dissipation coil pipe, of the fan-shaped coil and are used for providing real-time temperature acquisition data for heat balance control. By optimizing the design of the magnetic coupling mechanism and the heat balance capacity, the operation temperature of the coil can be reduced, and the transmission efficiency and the loading capacity of the system can be improved.

Description

Technical Field

[0001] This invention relates to the field of magnetic coupling wireless power transfer technology, and in particular to the magnetic coupling mechanism of a wireless power transfer system and its multi-mode thermal equalization control method. Background Technology

[0002] Wireless power transfer (WPT) is a technology that uses electromagnetic fields to transmit electrical energy over long distances. This technology has wide applications in electric vehicles, drones, and robotics. The rapid development of WPT has not only driven innovation in new electronic devices but also made possible the widespread adoption of smart cities, automated systems, and electric vehicles in the future.

[0003] In wireless power transmission systems, the design of the magnetic coupling mechanism plays a crucial role in transmission efficiency and stability. As a key component of the system, the magnetic coupling mechanism directly affects the efficiency of the entire wireless power transmission process. However, due to factors such as excessive heat generation at the transmitting end and variations in load in practical applications, wireless power transmission systems may face problems such as performance degradation, reduced efficiency, and safety hazards. Summary of the Invention

[0004] This invention provides a magnetic coupling mechanism for a wireless power transmission system and a multi-mode thermal equalization control method thereof, which can effectively solve the problems in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A magnetic coupling mechanism for a wireless power transmission system, the wireless power transmission system comprising a transmitter and a receiver, the magnetic coupling mechanism comprising: The magnetic energy emission structure, located at the emission end, consists of three identical sector coils. The three sector coils are located on three mutually parallel planes with equal spacing between adjacent planes and are evenly distributed around the same central axis in the circumferential direction. The three sector coils are arranged in parallel to adapt to time-division switching control of single coil, double coil, or triple coil. The magnetic energy receiving structure, located at the receiving end, is a square planar spiral coil. The side length of the square planar spiral coil is the same as the diameter of the sector coil, and it is arranged parallel to and directly opposite the three sector coils. A water-cooling device is installed on the side of the magnetic energy emitting structure that is away from the magnetic energy receiving structure. It includes three sets of identical fan-shaped heat dissipation coils, and the three sets of fan-shaped heat dissipation coils correspond one-to-one with the three fan-shaped coils and are closely adjacent to each other. Multiple temperature sensors are distributed on the side of the sector coil facing the sector heat sink to provide real-time temperature acquisition data for thermal equilibrium control.

[0006] Furthermore, the transmitting end of the wireless power transmission system also includes an AC power grid and a full-bridge rectifier, a transmitting end full-bridge inverter, and a transmitting end resonant network; The transmitter-side full-bridge inverter consists of three parallel full-bridge inverters, and the transmitter-side resonant network consists of three identical LCC-type resonant circuits, with capacitors... The branch circuit uses a two-way switch; The transmitter full-bridge inverter, the transmitter resonant network, and the magnetic energy emission structure are connected by three branches. Each branch consists of a full-bridge inverter, an LCC resonant circuit, and a sector coil.

[0007] Furthermore, the AC power grid, after being rectified by the full-bridge rectifier, can be equivalent to a DC power supply and connected to the full-bridge inverter at the transmitting end.

[0008] Furthermore, the receiving end also includes a receiving end resonant network, a receiving end full-bridge rectifier, and a receiving end battery load connected in sequence; The receiving end resonant network is a series compensation circuit, and the receiving end full-bridge rectifier is a full-bridge rectifier.

[0009] Furthermore, the three sets of fan-shaped heat dissipation coils are connected in series, and the fan-shaped pipes in each set of fan-shaped heat dissipation coils are connected in parallel.

[0010] Furthermore, the fan-shaped heat dissipation coil is a hollow structure with a apex angle of slightly less than 120°.

[0011] Furthermore, the cross-section of the cooling medium in the fan-shaped heat dissipation coil is rectangular.

[0012] Furthermore, the fan-shaped heat dissipation coil is made of oxygen-free copper material.

[0013] Furthermore, the three sector coils partially overlap in their horizontal projections. Decoupling is achieved by adjusting their apex angle parameters and combining them with mutual inductance calculations, as detailed below: Step 1: The three sector coils at the transmitting end are numbered sequentially as sector coil one, sector coil two, and sector coil three. The outermost turn radius R and number of turns N of the sector coils are given, as well as the side length d of the square planar spiral coil and the vertical height h between the magnetic energy transmitting structure and the magnetic energy receiving structure. Step 2: Preset the initial value of the apex angle of the sector coil to θ0=120°, the apex angle variable θ, and the apex angle change step size Δθ. Establish a spatial rectangular coordinate system with the center of the bottommost sector coil of the transmitter as the origin. Define the xoy plane as the plane where the bottommost sector coil of the transmitter is located, and the z-axis points to the direction of the square plane spiral coil. Step 3: Adjust the vertex angle variable θ in increments of Δθ, and always maintain the overall circumferential symmetry of the three sector coils during the adjustment process, so that the projections of sector coil 1, sector coil 2 and sector coil 3 on the xoy plane form a partially overlapping area, and the three overlapping parts have the same shape, all of which are sectors with the center as the origin, radius R and vertex angle θ-120°. Step 4: After each apex adjustment, calculate the mutual inductance between the corresponding sector coil one and sector coil two. Mutual induction The calculation formula is as follows: in, Let i be the mutual inductance between the i-th turn of sector coil one and the j-th turn of sector coil two; Step 5: Record the mutual inductance value corresponding to each vertex and draw the mutual inductance diagram. The curve varies with the apex angle; based on the curve of mutual inductance varying with the center of gravity, the extreme point where the mutual inductance is closest to 0 is obtained, and the apex angle corresponding to this extreme point is recorded as the decoupling apex angle. Based on the projected symmetrical structure of three sector coil units, the mutual inductance between sector coil one and sector coil three at the same vertex is... Mutual inductance between sector coil two and sector coil three Mutual inductance and mutual inductance They are equal, therefore the decoupling vertices are equal. This refers to the decoupling parameters between the three sector coils, specifically the decoupling apex angle. As the final apex of the sector coil.

[0014] The present invention also provides a multi-mode thermal equalization control method, applied to the magnetic coupling mechanism of the wireless power transmission system, the method comprising the following steps: The preset single-run time of a single sector coil is Δt, and the maximum system run time is... ; The operating mode of the transmitter is determined according to the load requirements of the receiver, wherein the operating mode includes low power mode, medium power mode and high power mode; According to the selected operating mode, the corresponding transmitter full-bridge inverter excitation control strategy is executed to drive the corresponding transmitter sector coil and its connected LCC resonant circuit to operate. In the high power mode, the synchronous linkage water cooling device performs temperature closed-loop control. The control transmitter continues to operate according to the rules of the corresponding operating mode until the system operating time reaches [a certain threshold]. Or the system triggers a stop command.

[0015] Furthermore, the excitation control strategy in the low-power mode is as follows: Set initial time ,exist The transmitter full-bridge inverter is energized only at one time, so that the sector coil and the LCC resonant circuit connected to it are put into operation. Every time interval Δt elapses, the excitation of full-bridge inverter device two and full-bridge inverter device three is switched sequentially while the previous inverter device is shut down, forming a single-coil cyclic operation mode with a period of T=3Δt, until the system stops operating.

[0016] Furthermore, the excitation control strategy in the medium power mode is as follows: Set initial time ,exist The full-bridge inverter device 1 and full-bridge inverter device 2 at the transmitting end are constantly energized, so that the sector coil 1 and sector coil 2 at the transmitting end and their respective connected LCC resonant circuits are put into operation; Every time interval Δt elapses, the excitation combination is switched in the following order: full-bridge inverter 1 and full-bridge inverter 2, full-bridge inverter 2 and full-bridge inverter 3, and full-bridge inverter 3 and full-bridge inverter 1, forming a dual-coil alternating operation mode with a period of T=3Δt, until the system stops operating.

[0017] Furthermore, the excitation control strategy in the high-power mode is as follows: The full-bridge inverters 1, 2, and 3 at the transmitting end are continuously excited to keep the three sector coils and their respective resonant circuits running. Temperatures at n high-temperature points on the lower surface of each sector coil are collected using temperature sensors. Given x = 1, 2, ..., n, calculate the average temperature value. ; Set temperature limit Start-up temperature and shut-off temperature ,like ≥ or ≥ If so, the water cooling system will be activated; if < and ≤ If so, then shut down the water cooling device.

[0018] Furthermore, when the magnetic energy emission structure operates in low-power or medium-power mode, for inverters requiring excitation, at the moment before excitation is applied, the resonant circuit connected to it is located in... The bidirectional switch on the branch applies excitation; for inverters that need to have their excitation disconnected, at the moment after the excitation is disconnected, the resonant circuit connected to it is located at... The bidirectional switch on the branch disconnects the excitation; When the magnetic energy emission structure operates in high-power mode, at the moment before excitation is applied to the three inverters, the three resonant circuits located at... Both bidirectional switches on the branch are energized.

[0019] The technical solution of this invention can achieve the following technical effects: The magnetic energy transmitting structure in this invention comprises three identical sector coil units, which are uniformly arranged circumferentially around the same common central axis and located on three mutually parallel planes. The distance between adjacent planes is the same, and the horizontal projections of the sector coils partially overlap to facilitate decoupling design. Its magnetic energy receiving structure is a square planar spiral coil, which has the characteristics of compact design and high space utilization, and can better adapt to the internal space of the device.

[0020] The decoupling method of the magnetic coupling mechanism in this invention includes mutual inductance calculation of the multi-coil combination magnetic coupling mechanism at the transmitting end and optimization of the apex angle of the sector coil unit at the transmitting end. The mutual inductance calculation of the three sector coil combinations at the transmitting end is performed by decomposing the sector coils into multiple turns of sector coil winding and calculating the mutual inductance between the sector coils of the transmitting end magnetic coupling mechanism. The optimization of the apex angle of the transmitting end coil unit, under the premise of limited basic geometric dimensions, involves changing the apex angle of the sector coils to create partial overlap between adjacent coils, thereby changing the mutual inductance value between the coils. The mutual inductance value corresponding to different sector coil apex angles is then calculated using the mutual inductance calculation formula to find the coil apex angle value corresponding to the decoupling point, which is used as the final design of the coil apex angle. This decoupling design can effectively eliminate or weaken the cross-coupling between the sector coils of the transmitting end magnetic coupling mechanism, thereby achieving independent control of each coil and significantly improving the transmission efficiency and stability of the overall system.

[0021] The multi-mode thermal equalization control method in this invention, under low-power and medium-power operation modes, minimizes the connection time of individual sector coils by cyclically connecting three sector coils while ensuring transmission power. This allows the coils to self-heat during dormancy, eliminating the need for water cooling and reducing system energy consumption. In high-power operation mode, a temperature sensor installed on the transmitting end magnetic coupling mechanism continuously monitors the temperature of the transmitting end sector coils. When any temperature reaches a preset temperature limit or the average value reaches the start-up temperature, the water cooling device installed on the transmitting end magnetic coupling mechanism is activated. The cooling coils of the water cooling device are identical in shape to the sector coils of the transmitting end magnetic coupling mechanism, corresponding one-to-one and closely adjacent, achieving maximum heat dissipation with minimal heat dissipation material. When any temperature value is below the preset temperature limit and the average value is less than the shutdown temperature, the water cooling device installed on the transmitting end magnetic coupling mechanism is shut down. Compared to the cooling control of traditional power transmission systems, this multi-mode thermal equalization control method for the magnetic coupling mechanism can reduce the temperature of the transmitting end magnetic coupling mechanism with lower energy consumption. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure and connection of a wireless power transmission system; Figure 2 A schematic diagram of a magnetic coupling mechanism consisting of three sector coils and a square planar helical coil; Figure 3 A top view of three sector coils; Figure 4 A topology diagram of a wireless power transfer system comprising a magnetic coupling mechanism consisting of a combination of multi-sector coils and square planar helical coils; Figure 5 This is a schematic diagram of the water-cooling device. Figure 6 A schematic diagram of the water-cooled heat dissipation coil and its coolant flow direction; Figure 7 This is a flowchart for multi-mode thermal equilibrium control. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] Example 1: like Figures 1-4 As shown, the present invention proposes a magnetic coupling mechanism for a wireless power transmission system. The wireless power transmission system includes a transmitter and a receiver, and the magnetic coupling mechanism includes a magnetic energy transmitting structure disposed at the transmitter and a magnetic energy receiving structure disposed at the receiver. The magnetic energy emission structure consists of three identical sector coils, which are located on three parallel planes with equal spacing between adjacent planes and are evenly distributed around the same central axis in the circumferential direction. The three sector coils are connected in parallel, which is suitable for time-division switching control of single, double, or triple coils. The magnetic energy receiving structure is a square planar spiral coil. The side length of the square planar spiral coil is the same as the diameter of the sector coil, and it is arranged parallel to and directly opposite the three sector coils. The water cooling device is located on the side of the magnetic energy emitting structure away from the magnetic energy receiving structure. It includes three sets of identical fan-shaped heat dissipation coils, which correspond one-to-one with the three fan-shaped coils and are closely adjacent to each other. Multiple temperature sensors are distributed on the side of the fan-shaped coil facing the fan-shaped heat sink to provide real-time temperature acquisition data for thermal equilibrium control.

[0027] Three sector coils generate a symmetrical high-frequency alternating magnetic field around a common central axis. Because the square planar helical coil at the receiving end is parallel and directly opposite the sector coil array at the transmitting end, and the side length matches the diameter of the sector coil, the alternating magnetic field can efficiently pass through the receiving coil. According to the principle of electromagnetic induction, a high-frequency alternating current will be induced in the receiving coil, realizing the transmission of wireless power.

[0028] During wireless power transmission, the resistance loss and core loss of the coil generate heat, causing the coil temperature to rise. Temperature sensors arranged on the lower surface of each sector coil collect coil temperature data in real time. The temperature sensors can transmit the collected temperature signals to a water-cooling device, which is then activated as needed to cool each sector coil.

[0029] The three sector coils are evenly arranged circumferentially and set up in parallel at equal intervals, which optimizes the uniformity of the magnetic field distribution and reduces mutual inductance interference between coils. The three sector coils are set up in parallel, and can be flexibly switched between single, double, or triple coils through independent excitation, reducing ineffective energy consumption and improving power transmission efficiency. The side length of the square coil at the receiving end matches the diameter of the sector coils and is parallel and directly opposite each other, maximizing the magnetic field coupling area. The introduction of temperature sensors and water cooling devices allows for real-time acquisition of temperature data of the core heating area of ​​the coils, enabling the three sets of independent sector heat dissipation coils to provide directional heat dissipation for individual heating coils, resulting in higher heat dissipation efficiency.

[0030] The transmitting end of the wireless power transmission system in this invention also includes an AC power grid and a full-bridge rectifier, a full-bridge inverter at the transmitting end, and a resonant network at the transmitting end; The AC power grid, after being rectified by a full-bridge rectifier, can be equivalent to a DC power supply, which is then connected to the transmitter's full-bridge inverter. The transmitter's full-bridge inverter consists of three parallel full-bridge inverters, and the transmitter's resonant network consists of three identical LCC-type resonant circuits, with capacitors... The branch circuit uses a two-way switch; The transmitter full-bridge inverter, the transmitter resonant network, and the magnetic energy emission structure are connected by three branches. Each branch consists of a full-bridge inverter, an LCC resonant circuit, and a sector coil.

[0031] LCC-type resonant circuits, by introducing an additional resonant capacitor, can achieve a constant current characteristic of the primary side current at a specific frequency, independent of the load, and easily implement soft switching, thereby significantly improving conversion efficiency and transmission stability. In the capacitor... The branch circuit uses a bidirectional switch. Under the premise of ensuring power stability during the wireless power transmission process of the system, the bidirectional switch controls the opening and closing of the branch circuit. This prevents mutual inductance between the resonant circuit connected to the receiving coil and the transmitting sector coil in the dormant state, thereby preventing the induced current in the dormant branch circuit from damaging the circuit components and protecting the system operation from being affected.

[0032] The receiving end of this invention also includes a receiving end resonant network, a receiving end full-bridge rectifier, and a receiving end battery load connected in sequence. The receiver resonant network is a series compensation circuit to reduce the weight and complexity of the receiver on the device side; the receiver full-bridge rectifier is a full-bridge rectifier consisting of four rectifier diodes and connected to a filter capacitor to achieve efficient and high-quality DC output.

[0033] like Figures 5-6As shown, the fan-shaped heat sink coil is a hollow structure with a apex angle of slightly less than 120°, and is made of oxygen-free copper material. Preferably, oxygen-free copper C10200 is selected. Compared with traditional heat dissipation material aluminum alloy, oxygen-free copper C10200 has higher thermal conductivity and better ductility. In addition, the flow cross section of the cooling medium in the fan-shaped heat sink coil is rectangular. Compared with the traditional circular flow cross section, the rectangular flow cross section has the characteristics of larger contact area with the coil and higher space utilization.

[0034] In the preferred embodiment, the three sets of fan-shaped heat dissipation coils are connected in series, and the fan-shaped pipes in each set of fan-shaped heat dissipation coils are connected in parallel.

[0035] The three sets of fan-shaped heat dissipation coils are connected in series, allowing the coolant to circulate between the heat dissipation coils and the cooling device. This absorbs the heat generated by the magnetic energy emission structure in a timely manner and carries it to the cooling device for dissipation, achieving a continuous and efficient cooling effect. Meanwhile, the fan-shaped pipes inside each set of fan-shaped heat dissipation coils are connected in parallel, increasing the contact area between the cooling water and the coils and improving the heat dissipation rate of a single coil.

[0036] In this invention, the three sector coils partially overlap in their horizontal projections. Decoupling design is achieved by adjusting their apex angle parameters and combining them with mutual inductance calculations. The decoupling design method includes mutual inductance calculation of the transmitting sector coils and optimization of the apex angle dimensions of the transmitting sector coils, as detailed below: Step 1: Number the three sector coils at the transmitting end as sector coil one, sector coil two, and sector coil three in sequence. Given the outermost turn radius R and number of turns N of the sector coils, the side length d of the square planar spiral coil, and the vertical height h between the magnetic energy transmitting structure and the magnetic energy receiving structure; Step 2: Set the initial value of the apex angle of the sector coil to θ0=120°, the apex angle variable θ, and the apex angle change step size Δθ. Establish a spatial rectangular coordinate system with the center of the bottommost sector coil at the transmitter as the origin. Define the xoy plane as the plane where the bottommost sector coil at the transmitter is located, and the z-axis points to the direction of the square plane spiral coil. Step 3: Adjust the vertex angle variable θ in increments of Δθ, and always maintain the overall circumferential symmetry of the three sector coils during the adjustment process, so that the projections of sector coil 1, sector coil 2 and sector coil 3 on the xoy plane form a partially overlapping area, and the three overlapping parts have the same shape, all of which are sectors with the center as the origin, radius R and vertex angle θ-120°. Step 4: After each apex adjustment, calculate the mutual inductance between the corresponding sector coil one and sector coil two. Mutual induction The calculation formula is as follows: in, Let i be the mutual inductance between the i-th turn of sector coil one and the j-th turn of sector coil two; Step 5: Record the mutual inductance value corresponding to each vertex and draw the mutual inductance diagram. The curve varies with the apex angle; based on the curve of mutual inductance varying with the center of gravity, the extreme point where the mutual inductance is closest to 0 is obtained, and the apex angle corresponding to this extreme point is recorded as the decoupling apex angle. Based on the projected symmetrical structure of three sector coil units, the mutual inductance between sector coil one and sector coil three at the same vertex is... Mutual inductance between sector coil two and sector coil three Mutual inductance and mutual inductance They are equal, therefore the decoupling vertices are equal. This refers to the decoupling parameters between the three sector coils, specifically the decoupling apex angle. As the final apex of the sector coil.

[0037] By adjusting the apex angle of the sector coils and utilizing symmetry, the optimal apex angle parameter is found to make the mutual inductance between the coils approach zero, thereby achieving decoupling between the three sets of sector coils at the transmitting end. This decoupling design can effectively eliminate or weaken the cross coupling between the three sector coils at the transmitting end, thereby enabling independent control of each coil and significantly improving the transmission efficiency and stability of the overall system.

[0038] Example 2 This embodiment describes a multi-mode thermal equilibrium control method applied to the magnetic coupling mechanism in Embodiment 1, such as... Figure 7 As shown, the multi-mode thermal equilibrium control method includes the following steps: The preset single-run time of a single sector coil is Δt, and the maximum system run time is... ; The operating mode of the transmitter is determined based on the load requirements of the receiver. The operating modes include low power mode, medium power mode and high power mode. According to the selected operating mode, the corresponding transmitter full-bridge inverter excitation control strategy is executed to drive the corresponding transmitter sector coil and its connected LCC resonant circuit to operate. In the high power mode, the synchronous linkage water cooling device performs temperature closed-loop control. The control transmitter continues to operate according to the rules of the corresponding operating mode until the system operating time reaches [a certain threshold]. Or the system triggers a stop command.

[0039] The magnetic coupling mechanism employs a multi-mode thermal equalization control method, including low-power, medium-power, and high-power thermal equalization control methods. The low-power and medium-power control methods minimize the connection time of individual sector coils, allowing them to self-heat during dormancy. The high-power control method utilizes a specially designed water-cooling device to dissipate heat from the coils, mitigating overheating during operation and ensuring efficient, stable, and safe system operation. This multi-mode thermal equalization control method not only helps reduce coil operating temperature and system power consumption but also significantly improves system transmission efficiency and load-carrying capacity, making it of significant value in the field of wireless power transfer technology.

[0040] The excitation control strategy in low-power mode is as follows: Set initial time ,exist The transmitter full-bridge inverter is energized only at one time, so that the sector coil and the LCC resonant circuit connected to it are put into operation. Every time interval Δt elapses, the excitation of full-bridge inverter device two and full-bridge inverter device three is switched sequentially while the previous inverter device is shut down, forming a single-coil cyclic operation mode with a period of T=3Δt, until the system stops operating.

[0041] Specifically, such as Figure 7 As shown, when the transmitter is in low-power mode, at system startup, i.e., at the beginning of the first Δt, the bidirectional switch 1 in resonant circuit 1 is first excited, and then the inverter 1 on the same branch is excited; at the end of the first Δt, i.e., at the beginning of the second Δt, the bidirectional switch 2 in resonant circuit 2 is first excited, and then the inverter 2 on the same branch is excited, and then the inverter 1 is first de-excited, and then the bidirectional switch 1 is de-excited; at the end of the second Δt, i.e., at the beginning of the third Δt, the bidirectional switch 3 in resonant circuit 3 is first excited, and then the inverter 1 on the same branch is excited. The system applies excitation to inverter 3, then disconnects the excitation to inverter 2, and then disconnects the excitation to bidirectional switch 2. At the end of the third Δt, which is the start of the next cycle, the system first applies excitation to bidirectional switch 1 located in resonant circuit 1, then applies excitation to inverter 1 on the same branch, and then disconnects the excitation to inverter 3, and then disconnects the excitation to bidirectional switch 3. These three Δt constitute a cycle, and the system operates in this cyclic mode. At the end of each Δt, it is determined whether the cumulative operating time of the system is greater than the maximum operating time. If so, all excitations of the system are immediately disconnected and the system stops operating; otherwise, the system continues to operate.

[0042] The low-power mode thermal equilibrium control method is characterized by the following: due to the small system transmission power and the small overall heat generation of the coil, the three branches can be connected one at a time by cyclically exciting the transmitter inverter and using a bidirectional switch, and they can be operated in sequence. While achieving stable power transmission, the two sector coils in the dormant state can reduce their own temperature through self-heating without the need for water cooling devices. Compared with the continuous operation of the coils in the traditional control mode, this control method has better heat dissipation and energy saving effect.

[0043] The excitation control strategy in medium power mode is as follows: Set initial time ,exist The full-bridge inverter device 1 and full-bridge inverter device 2 at the transmitting end are constantly energized, so that the sector coil 1 and sector coil 2 at the transmitting end and their respective connected LCC resonant circuits are put into operation; Every time interval Δt elapses, the excitation combination is switched in the following order: full-bridge inverter 1 and full-bridge inverter 2, full-bridge inverter 2 and full-bridge inverter 3, and full-bridge inverter 3 and full-bridge inverter 1, forming a dual-coil alternating operation mode with a period of T=3Δt, until the system stops operating.

[0044] Specifically, such as Figure 7 As shown, when the transmitter is in medium power mode, at system startup, i.e., at the beginning of the first Δt, excitation is first applied to bidirectional switch 1 in resonant circuit 1 and bidirectional switch 2 in resonant circuit 2, and then excitation is applied to inverters 1 and 2 on their respective branches; at the end of the first Δt, i.e., at the beginning of the second Δt, excitation is first applied to bidirectional switch 3 in resonant circuit 3, and then excitation is applied to inverters 3 on their respective branches. Subsequently, the excitation of inverter 1 is first disconnected, and then the excitation of bidirectional switch 1 is disconnected, while inverters 2 and bidirectional switch 2 remain energized; at the end of the second Δt, i.e., at the beginning of the third Δt, excitation is first applied to bidirectional switch 1 in resonant circuit 1, and then excitation is applied to inverters 1 and 2 on their respective branches. Inverter 1 on the branch is energized, then inverter 2 is de-energized first, then bidirectional switch 2 is de-energized, while inverter 3 and bidirectional switch 3 remain energized. At the end of the third Δt, which is the start of the next cycle, bidirectional switch 2 in the resonant circuit 2 is energized first, then inverter 2 on the same branch is energized, then inverter 3 is de-energized first, then bidirectional switch 3 is de-energized, while inverter 1 and bidirectional switch 1 remain energized. This three Δt constitutes a cycle, and the system operates in this cyclical pattern. At the end of each Δt, it is determined whether the cumulative operating time of the system is greater than the maximum operating time. If so, all energies of the system are immediately de-energized, and operation stops; otherwise, the system continues to operate.

[0045] The characteristics of the medium-power mode thermal balance control method are as follows: Compared with the low-power mode thermal balance control, the system transmission power increases and the overall heat generation of the coil increases. However, the inverter can still be cyclically excited and bidirectionally switched so that two of the three branches are connected at a time and run in sequence. While achieving stable power transmission, a sector coil in a dormant state can reduce its own temperature through self-heating without the need for water cooling. Compared with the continuous operation of the coil in the traditional control mode, this control method has better heat dissipation and energy saving effect.

[0046] The excitation control strategy in high-power mode is as follows: The full-bridge inverters 1, 2, and 3 at the transmitting end are continuously excited to keep the three sector coils and their respective resonant circuits running. Temperatures at n high-temperature points on the lower surface of each sector coil are collected using temperature sensors. Given x = 1, 2, ..., n, calculate the average temperature value. ; Set temperature limit Start-up temperature and shut-off temperature ; like ≥ or ≥ If it is determined that the magnetic energy emission structure is overheating, then the water cooling device is activated to cool the magnetic energy emission structure. like < and ≤ If it is determined that the magnetic energy emission structure has stopped overheating, the water cooling device is turned off to achieve closed-loop temperature control.

[0047] Specifically, such as Figure 7 As shown, when the transmitter is in high-power mode, after the system starts, it first applies excitation to bidirectional switches 1, 2, and 3, and then applies excitation to inverters 1, 2, and 3. Excitation is maintained on all components until the system stops working. By establishing an electromagnetic-thermal multiphysics simulation model of the magnetic coupling mechanism, the temperatures of the lower surfaces of the three sector coils at the transmitter are determined. Temperature sensors are placed at n points with higher temperatures on the lower surfaces of each sector coil, and the temperatures at each point are denoted as... x = 1, 2, ..., n. Set the temperature limit. Start-up temperature and shut-off temperature Calculate the average temperature value based on the n temperature values ​​detected by the temperature sensor. If any temperature value is greater than or equal to ,or ≥ The system determines that the transmitter's magnetic coupling mechanism is overheating and activates a water-cooling device to cool it. After running for one Δt, the temperature is checked again. If any temperature value is less than... ,and ≤ The system determines that the transmitter's magnetic coupling mechanism has stopped overheating and shuts down the water cooling device. After running for another Δt, the temperature is checked again. If any temperature value is greater than or equal to... ,or ≥ The water cooling device is turned on again at each interval, and this process is repeated until the system stops. At the end of each Δt interval, it is determined whether the cumulative running time of the system is greater than the maximum running time. If so, all excitations to the system are immediately disconnected and the system stops running; otherwise, the system continues to run.

[0048] The high-power mode thermal equalization control method is characterized by the following: compared to low-power and medium-power mode thermal equalization control, the system transmits a large amount of power, and the overall heat generation of the coils increases significantly. At this point, all the sector coils at the transmitting end need to be operational. The method of self-heating the coils by cyclically exciting the transmitting inverter and using bidirectional switches cannot be used; a water-cooling device is required for auxiliary heat dissipation. Thanks to the special design of the cooling coil in the water-cooling device, the water-cooling device proposed in this invention features high heat dissipation efficiency and low power consumption.

[0049] When the magnetic energy emission structure operates in low-power or medium-power mode, for an inverter that requires excitation, at the moment before excitation is applied, the resonant circuit connected to it is located in... The bidirectional switch on the branch applies excitation; for inverters that need to have their excitation disconnected, at the moment after the excitation is disconnected, the resonant circuit connected to it is located at... The bidirectional switch on the branch line disconnects the excitation.

[0050] When the magnetic energy emission structure operates in high-power mode, at the moment before excitation is applied to the three inverters, the three resonant circuits located at... Both bidirectional switches on the branch are energized.

[0051] In the thermal balance control of low-power mode, medium-power mode, and high-power mode, the inverters on the same branch are started after the bidirectional switch and shut down before it. The purpose is to prevent no-load overcurrent under series resonance compensation at the inverter's downstream end when the bidirectional switch is adjusted. In the thermal balance control of low-power mode and medium-power mode, the inverters and bidirectional switches that are pre-started next are started before the inverters and bidirectional switches that are pre-shut down last time. The purpose is to prevent the transmission power from being reduced or interrupted due to excitation delay caused by error.

[0052] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to implement the steps of a multi-mode thermal equilibrium control method.

[0053] The present invention also provides a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of a multi-mode thermal equilibrium control method.

[0054] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0055] This invention is described with reference to flowchart illustrations of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each step in the flowchart, and combinations of steps in the flowchart, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the steps in the flowchart. Figure 1 A device for a function specified in one or more processes.

[0056] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 The function specified in one or more processes.

[0057] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 Steps of a specified function in one or more processes.

[0058] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A magnetic coupling mechanism of a wireless power transfer system, the wireless power transfer system consisting of two parts, a transmitting end and a receiving end, characterized in that, The magnetic coupling mechanism includes: The magnetic energy emission structure, located at the emission end, consists of three identical sector coils. The three sector coils are located on three mutually parallel planes, with equal spacing between adjacent planes, and are evenly distributed circumferentially around the same central axis. The three sector coils are arranged in parallel. The magnetic energy receiving structure, located at the receiving end, is a square planar spiral coil. The side length of the square planar spiral coil is the same as the diameter of the sector coil, and it is arranged parallel to and directly opposite the three sector coils. A water-cooling device is installed on the side of the magnetic energy emitting structure away from the magnetic energy receiving structure. It includes three sets of identical fan-shaped heat dissipation coils, and the three sets of fan-shaped heat dissipation coils correspond one-to-one with the three fan-shaped coils and are closely adjacent to each other. Multiple temperature sensors are distributed on the side of the sector coil facing the sector heat sink to provide real-time temperature acquisition data for thermal equilibrium control.

2. The magnetic coupling mechanism of the wireless power transmission system according to claim 1, characterized in that, The transmitting end of the wireless power transmission system also includes an AC power grid and a full-bridge rectifier, a full-bridge inverter at the transmitting end, and a resonant network at the transmitting end. The transmitter-side full-bridge inverter consists of three parallel full-bridge inverters, and the transmitter-side resonant network consists of three identical LCC-type resonant circuits, with capacitors... The branch circuit uses a two-way switch; The transmitter full-bridge inverter, the transmitter resonant network, and the magnetic energy emission structure are connected by three branches. Each branch consists of a full-bridge inverter, an LCC resonant circuit, and a sector coil.

3. The magnetic coupling mechanism of the wireless power transmission system according to claim 2, characterized in that, The AC power grid can be rectified by the full-bridge rectifier and converted into an equivalent DC power supply, which is then connected to the full-bridge inverter at the transmitting end.

4. The magnetic coupling mechanism of the wireless power transmission system according to claim 1, characterized in that, The receiver also includes a receiver resonant network, a receiver full-bridge rectifier, and a receiver battery load connected in sequence. The receiving end resonant network is a series compensation circuit, and the receiving end full-bridge rectifier is a full-bridge rectifier.

5. The magnetic coupling mechanism of the wireless power transmission system according to claim 1, characterized in that, The three sets of fan-shaped heat dissipation coils are connected in series, while the fan-shaped pipes in each set of fan-shaped heat dissipation coils are connected in parallel.

6. The magnetic coupling mechanism of the wireless power transmission system according to claim 1, characterized in that, The fan-shaped heat sink has a hollow structure with a apex angle of slightly less than 120°.

7. The magnetic coupling mechanism of the wireless power transmission system according to claim 1, characterized in that, The cross-section of the cooling medium in the fan-shaped heat sink is rectangular.

8. The magnetic coupling mechanism of the wireless power transmission system according to claim 1, characterized in that, The fan-shaped heat dissipation coil is made of oxygen-free copper.

9. The magnetic coupling mechanism of the wireless power transmission system according to claim 1, characterized in that, The three sector coils partially overlap in their horizontal projections. Decoupling design is achieved by adjusting their apex angle parameters and combining mutual inductance calculations, as detailed below: Step 1: The three sector coils at the transmitting end are numbered sequentially as sector coil one, sector coil two, and sector coil three. The outermost turn radius R and number of turns N of the sector coils are given, as well as the side length d of the square planar spiral coil and the vertical height h between the magnetic energy transmitting structure and the magnetic energy receiving structure. Step 2: Preset the initial value of the apex angle of the sector coil to θ0=120°, the apex angle variable θ, and the apex angle change step size Δθ. Establish a spatial rectangular coordinate system with the center of the bottommost sector coil of the transmitter as the origin. Define the xoy plane as the plane where the bottommost sector coil of the transmitter is located, and the z-axis points to the direction of the square plane spiral coil. Step 3: Adjust the vertex angle variable θ in increments of Δθ, and always maintain the overall circumferential symmetry of the three sector coils during the adjustment process, so that the projections of sector coil 1, sector coil 2 and sector coil 3 on the xoy plane form a partially overlapping area, and the three overlapping parts have the same shape, all of which are sectors with the center as the origin, radius R and vertex angle θ-120°. Step 4: After each apex adjustment, calculate the mutual inductance between the corresponding sector coil one and sector coil two. Mutual induction The calculation formula is as follows: in, Let i be the mutual inductance between the i-th turn of sector coil one and the j-th turn of sector coil two; Step 5: Record the mutual inductance value corresponding to each vertex and draw the mutual inductance diagram. The curve varies with the apex angle; based on the curve of mutual inductance varying with the center of gravity, the extreme point where the mutual inductance is closest to 0 is obtained, and the apex angle corresponding to this extreme point is recorded as the decoupling apex angle. Based on the projected symmetrical structure of three sector coil units, the mutual inductance between sector coil one and sector coil three at the same vertex is... Mutual inductance between sector coil two and sector coil three Mutual inductance and mutual inductance They are equal, therefore the decoupling vertices are equal. This refers to the decoupling parameters between the three sector coils, specifically the decoupling apex angle. As the final apex of the sector coil.

10. A multi-mode thermal equalization control method, applied to the magnetic coupling mechanism of the wireless power transmission system as described in any one of claims 1-9, characterized in that, The method includes the following steps: The preset single-run time of a single sector coil is Δt, and the maximum system run time is... ; The operating mode of the transmitter is determined according to the load requirements of the receiver, wherein the operating mode includes low power mode, medium power mode and high power mode; According to the selected operating mode, the corresponding transmitter full-bridge inverter excitation control strategy is executed to drive the corresponding transmitter sector coil and its connected LCC resonant circuit to operate. In the high power mode, the synchronous linkage water cooling device performs temperature closed-loop control. The control transmitter continues to operate according to the rules of the corresponding operating mode until the system operating time reaches [a certain threshold]. Or the system triggers a stop command.

11. The multi-mode thermal equilibrium control method according to claim 10, characterized in that, The excitation control strategy in the low-power mode is as follows: Set initial time ,exist The transmitter full-bridge inverter is energized only at one time, so that the sector coil and the LCC resonant circuit connected to it are put into operation. Every time interval Δt elapses, the excitation of full-bridge inverter device two and full-bridge inverter device three is switched sequentially while the previous inverter device is shut down, forming a single-coil cyclic operation mode with a period of T=3Δt, until the system stops operating.

12. The multi-mode thermal equilibrium control method according to claim 10, characterized in that, The excitation control strategy in the medium power mode is as follows: Set initial time ,exist The full-bridge inverter device 1 and full-bridge inverter device 2 at the transmitting end are constantly energized, so that the sector coil 1 and sector coil 2 at the transmitting end and their respective connected LCC resonant circuits are put into operation; Every time interval Δt elapses, the excitation combination is switched in the following order: full-bridge inverter 1 and full-bridge inverter 2, full-bridge inverter 2 and full-bridge inverter 3, and full-bridge inverter 3 and full-bridge inverter 1, forming a dual-coil alternating operation mode with a period of T=3Δt, until the system stops operating.

13. The multi-mode thermal equilibrium control method according to claim 10, characterized in that, The excitation control strategy in the high-power mode is as follows: The full-bridge inverters 1, 2, and 3 at the transmitting end are continuously excited to keep the three sector coils and their respective resonant circuits running. Temperatures at n high-temperature points on the lower surface of each sector coil are collected using temperature sensors. Given x = 1, 2, ..., n, calculate the average temperature value. ; Set temperature limit Start-up temperature and shut-off temperature ,like ≥ or ≥ If so, the water cooling system will be activated; if < and ≤ If so, then shut down the water cooling device.

14. The multi-mode thermal equilibrium control method according to claim 10, characterized in that, When the magnetic energy emission structure operates in low-power or medium-power mode, for an inverter that requires excitation, at the moment before excitation is applied, the resonant circuit connected to it is located in... The bidirectional switch on the branch applies excitation; for inverters that need to have their excitation disconnected, at the moment after the excitation is disconnected, the resonant circuit connected to it is located at... The bidirectional switch on the branch disconnects the excitation; When the magnetic energy emission structure operates in high-power mode, at the moment before excitation is applied to the three inverters, the three resonant circuits located at... Both bidirectional switches on the branch are energized.

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