A directional wireless charging method based on magnetic resonance technology

Abstract

The present invention provides a directional wireless charging method based on magnetic resonance technology. The method includes a resonant coil that receives magnetic energy from a transmitting magnetic field through magnetic induction and outputs a resonant current with the same frequency as the transmitting magnetic field. The resonant current is input into a receiving coil to generate a receiving magnetic field with the same frequency as the transmitting magnetic field. The transmitting magnetic field and the receiving magnetic field form magnetic resonance for energy transmission. The present invention enables efficient one-to-one charging between a charging station and a vehicle without requiring precise positioning of the vehicle. Charging automatically stops when the distance between the vehicle and the charging station exceeds a set range.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile wireless charging, and in particular to a directional wireless charging method based on magnetic resonance technology. Background Art

[0002] The new energy market has experienced rapid growth in the past two years, with the proportion of new energy vehicles on the market increasing year by year. Consequently, a large number of charging stations have emerged. New energy vehicles are typically charged via plug-in charging. Limited by the number of electrical connections and charging stations, only one or a few electric vehicles can be charged at a time, leading to frequent queues on highways. Furthermore, charging stations are exposed to the elements, and the exposed charging ports require waterproofing and dustproofing. This inevitably leads to system failures in the charging station system, resulting in extensive maintenance and overhaul work, which has hindered the widespread adoption of plug-in charging stations.

[0003] To avoid these issues, a growing number of companies are actively developing wireless charging technology to address the challenges of electric vehicle charging. Existing wireless charging technology includes CN108819748A, a wireless charging system for electric vehicles. The document discloses a wireless charging method in which an oscillating current is passed through a transmitting coil, generating a regularly changing magnetic field. A receiving coil receives the magnetic energy and converts it into electrical energy, which is then transferred to a battery for storage.

[0004] Existing wireless charging technologies primarily utilize electromagnetic induction and magnetic field resonance. Electromagnetic induction wireless charging typically relies on one-to-one charging, requiring the transmitter and receiver coils to be relatively close together and requiring high positioning accuracy. The more accurate the positioning, the higher the charging efficiency. This requires a certain level of driving skill during charging. Furthermore, before each charge, the vehicle's position is time-consuming to calibrate, significantly increasing charging times.

[0005] Magnetic resonance charging allows for one-to-many charging within a range of centimeters to meters, thus minimizing vehicle location requirements and aligning with the principle that closer charging distances result in higher charging efficiency. However, since vehicles can charge at long distances, and multiple charging stations exist at a single charging station, when multiple vehicles are charging simultaneously, it's impossible to guarantee that a single station accurately matches each vehicle entering and exiting. This leads to inaccurate billing. Furthermore, the farther a vehicle is from the charging station, the lower the charging efficiency. This also results in significant energy waste when vehicles are charging over long distances for extended periods. Summary of the Invention

[0006] In view of this, the problem to be solved by the present invention is to provide a directional wireless charging method based on magnetic resonance technology, which can achieve one-to-one efficient charging between the charging pile and the vehicle without accurately fixing the vehicle position. When the distance between the vehicle and the charging pile exceeds the set range, charging will be automatically stopped.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A directional wireless charging method based on magnetic resonance technology includes a resonant coil, which receives magnetic energy from a transmitting magnetic field through magnetic induction and outputs a resonant current with the same frequency as the transmitting magnetic field. The resonant current is input into a receiving coil to generate a receiving magnetic field with the same frequency as the transmitting magnetic field.

[0009] Furthermore, the transmitting coil includes a first transmitting electrode and a second transmitting electrode, and the receiving coil includes a first receiving electrode and a second receiving electrode;

[0010] The first emitter and the second emitter are arranged with opposite polarities, and the first receiver and the second receiver are arranged with opposite rotation directions of the coils.

[0011] Furthermore, the magnetic flux lines between the first emitter and the second emitter are along the length direction of the charging parking space;

[0012] The resonant coil is arranged between the first receiving pole and the second receiving pole, and the axis of the resonant coil is arranged along the length direction of the vehicle.

[0013] Furthermore, a control module is electrically connected between the resonant coil and the receiving coil, and the control module is equipped with a common frequency strategy, including: collecting total current data output by the resonant coil, and outputting a number of periodically changing alternating current data through discrete Fourier transform;

[0014] The frequency of the AC power data with the largest amplitude is obtained and a main frequency is generated, and the control module outputs a resonant current with the same main frequency.

[0015] Furthermore, the resonant current output includes: obtaining peak data of the main frequency and generating a main amplitude, obtaining peak data of the second largest amplitude of the AC data and generating a negative amplitude, and determining whether the difference between the main amplitude and the secondary amplitude exceeds a first preset threshold, and if not, providing feedback indicating that the vehicle position is incorrect;

[0016] If yes, it is determined whether the main amplitude exceeds the second preset threshold. If not, feedback is given that the vehicle position is incorrect. If yes, feedback is given that the vehicle position is correct and charging starts, and the control module outputs the resonant current.

[0017] Furthermore, the control module is equipped with a delay strategy, including:

[0018] S1: Calculate the theoretical charging value based on the main amplitude and obtain the actual charging value of the battery;

[0019] S2: Determine whether the actual charging value meets the theoretical charging value. If not, delay the output time of the resonant current by N+1 delay periods, and loop step S2. If yes, stop looping.

[0020] Furthermore, the delay period is less than (1 / main frequency) / x, where x is not less than 20.

[0021] Furthermore, the output end of the control module is connected to an indication module, and the indication module is composed of a plurality of indicator lights.

[0022] Furthermore, the oscillating current frequencies corresponding to the transmitting coils of different charging parking spaces are set differently.

[0023] Furthermore, the control module and the indication module are both powered by a resonant coil.

[0024] The advantages and positive effects of the present invention are:

[0025] (1) By adding a resonant coil to the vehicle, a first emitter and a second emitter are buried underground in the charging parking space. An oscillating current is passed through the transmitting coil to output a uniformly changing transmitting magnetic field. A transmitting magnetic field parallel to the ground is formed between the first emitter and the second emitter. When the resonant coil enters the position between the first emitter and the second emitter, the power value of the resonant current output by the resonant coil increases, and the resonant current is input to the receiving coil, causing the receiving coil to generate a uniformly changing receiving magnetic field. The frequency of change of the transmitting magnetic field and the receiving magnetic field is the same. Wireless charging in the form of magnetic field resonance can improve the charging efficiency while reducing the accuracy requirement of the vehicle position.

[0026] Magnetic field resonance is achieved using only a single resonant coil (no algorithms or resonators are required), significantly reducing production costs. When the resonant coil is removed from between the first and second emitters, the resonant current power falls below a set power threshold, immediately stopping charging. This allows for efficient, one-to-one charging between the charging station and the vehicle, without requiring precise positioning of the vehicle. Charging automatically stops when the distance between the vehicle and the charging station exceeds a set range.

[0027] The frequency of the oscillating current is directly obtained by transmitting a magnetic field. When the oscillating current frequency is unstable due to aging of the power module or when a low-performance oscillator is used, the magnetic energy resonance efficiency between the transmitting and receiving magnetic fields can be guaranteed.

[0028] The resonant coil generates a resonant current with the same frequency as the oscillating current, and the receiving coil actively resonates with the transmitting coil to ensure that the vehicle can be charged normally under the transmitting magnetic field of any frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 This is an overall system structure diagram of a directional wireless charging method based on magnetic resonance technology of the present invention;

[0031] Figure 2 This is a winding principle diagram and magnetic flux distribution diagram of a transmitting coil in a directional wireless charging method based on magnetic resonance technology of the present invention.

[0032] In the figure: 1, vehicle; 101, first receiving electrode; 102, second receiving electrode; 103, resonant coil; 2, charging parking space; 301, first emitter; 302, second emitter. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0034] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a central component. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] The present invention provides a directional wireless charging method based on magnetic resonance technology, such as Figure 1As shown, the system includes a power module, the output of which is electrically connected to a transmitting coil. The power module outputs an oscillating current at a fixed frequency, causing the transmitting coil to produce a periodically varying transmitting magnetic field. To minimize space above ground and avoid collisions with vehicle 1, the transmitting coil and power module are buried below ground level.

[0037] The vehicle is equipped with a receiving coil and a resonant coil 103. The resonant coil 103 receives magnetic energy from the transmitting magnetic field and outputs a resonant current at the same frequency as the oscillating current. The resonant current is input into the receiving coil, generating a receiving magnetic field at the same frequency as the transmitting magnetic field. The transmitting and receiving magnetic fields resonate magnetically, transferring energy to charge the vehicle.

[0038] Vehicle 1 is equipped with a battery electrically connected to the receiving coil, storing the electrical energy received by the receiving coil. A control module is also included within the vehicle, which receives and adjusts the resonant current and outputs a resonant current with the same frequency as the oscillating current, ensuring strong coupling between the transmitting and receiving coils' magnetic fields and improving charging efficiency.

[0039] The output end of the control module is electrically connected to an indicator module, which is composed of a plurality of indicator lights. The closer the distance between the resonant coil 103 and the transmitting coil, the greater the electromotive force output by the resonant coil 103, and the more indicator lights that light up. The driver determines the position of the vehicle 1 based on the number of indicator lights that light up.

[0040] The structure of the transmitting coil is as follows Figure 2 As shown, the transmitting coil is wound into a U-shaped structure. The transmitting coil includes a first emitter 301 and a second emitter 302. The first emitter 301 is used to emit magnetic flux lines, and the second emitter 302 is used to receive magnetic flux lines.

[0041] A horizontal magnetic field parallel to the ground is generated between the first emitter 301 and the second emitter 302. Figure 1 As shown, the first emitter 301 and the second emitter 302 are respectively buried at the front end and the rear end of the charging parking space 2, and a horizontal magnetic field is generated in the middle section above the charging parking space 2 along the length direction of the charging parking space 2. Correspondingly, the axis of the resonant coil 103 is set horizontally along the length direction of the vehicle 1. When the resonant coil 103 is located between the first emitter 301 or the second emitter 302, the axis direction of the resonant coil 103 is parallel to the magnetic flux lines of the emitted magnetic field (the conversion efficiency of the magnetic field is the highest), and the larger the induced electromotive force output by the resonant coil 103. The control module controls the number of indicator lights that light up according to the size of the received induced electromotive force.

[0042] Preferably, the resonant coil 103 is positioned in the middle of the vehicle 1, directly between the first emitter 301 and the second emitter 302, resulting in a greater induced electromotive force. When parking, the driver can determine the vehicle's approximate location by observing the number of illuminated indicator lights. For example, the greater the number of illuminated indicator lights, the closer the distance between the transmitting and receiving coils.

[0043] Since the transmission between the transmitting coil and the receiving coil is carried out through magnetic energy resonance, and there is no requirement for the position between the transmitting coil and the receiving coil, only the magnitude of the induced electromotive force is judged to determine the approximate distance between the transmitting coil and the receiving coil. When the distance meets the requirement (the power exceeds the set threshold), charging can be started, which saves the parking time of the vehicle 1 before charging and ensures the charging efficiency of the vehicle 1.

[0044] During the charging process of vehicle 1, the driver can continue to adjust the position of vehicle 1 until the indicator light is fully lit. At this time, the transmitting coil and the receiving coil are completely opposite to each other, and the conversion efficiency of the energy in the transmitting magnetic field is the highest.

[0045] To further improve charging efficiency, the receiving coil includes a first receiving electrode 101 and a second receiving electrode 102. The first receiving electrode 101 is positioned opposite the first emitting electrode 301, and the second receiving electrode 102 is positioned opposite the second emitting electrode 302. When the indicator light is fully illuminated, the two receiving electrodes and the two emitting electrodes are aligned. The two receiving electrodes simultaneously receive the magnetic energy output by the transmitting coil, improving the efficiency of magnetic energy conversion.

[0046] Because the polarities of the first emitter 301 and the second emitter 302 are opposite, the coils of the first receiver 101 and the second receiver 102 are arranged in opposite directions, ensuring that the magnetic flux lines between the first emitter 301 and the first receiver 101 are always in the same direction (the magnetic flux lines between the second emitter 302 and the second receiver 102 are also always in the same direction). The first emitter 301 and the first receiver 101 can always resonate with each other, and the second emitter 302 and the second receiver 102 can also always resonate with each other, effectively improving the efficiency of power conversion.

[0047] Both the control module and the indicator module are powered directly by the resonant coil 103. Even if the vehicle 1's own power is completely depleted, normal charging of the vehicle 1 is not affected. When the control module detects that the power exceeds a set threshold, it outputs a resonant current, which flows simultaneously into the first receiving electrode 101 and the second receiving electrode 102.

[0048] The formula for calculating the magnetic field strength of a current-carrying coil is: H = N × I / Le, where H is the magnetic field strength, measured in A / m; N is the number of turns in the excitation coil; I is the excitation current (measured value), measured in A; and Le is the effective magnetic path length, measured in meters. This shows that magnetic field strength is positively correlated with excitation current.

[0049] The general formula for the electromotive force of the induced current in a changing magnetic field is: E = nΔφ / Δt, where n is the number of turns in the coil (the resonant coil), and Δφ / Δt is the rate of change of magnetic flux. From this formula, we can see that when the resonant coil and the transmitting coil are fixed in position, the resonant current must have the same frequency as the oscillating current.

[0050] However, there won't be just one charging station, which would waste resources and be inconvenient for multiple vehicles to charge. Setting up multiple wireless charging bays in an open environment, when multiple vehicles are charging simultaneously, will cause interference between the multiple transmitting bays and the geomagnetic field, which will affect the frequency of the resonant current.

[0051] To enable efficient one-to-one charging of vehicles, a common frequency strategy has been added to the control module, including: collecting the total current data output by the resonant coil, and then outputting the periodically changing AC data of the rod through discrete Fourier transform; obtaining the frequency of the AC data with the largest amplitude and generating the main frequency, and the control module outputs the resonant current with the same main frequency.

[0052] When a vehicle is parked while charging, the intensity of the transmitted magnetic field (hereinafter referred to as the interference magnetic field) generated by other charging spaces varies regularly, and accordingly, the effect of this magnetic field on the electromotive force varies regularly. The oscillating current is typically a sinusoidal wave. Discrete Fourier transform can separate the interference electromotive force generated by the interference magnetic field and the irregular electromotive force generated by the geomagnetic field, thereby improving the accuracy of the resonant current frequency.

[0053] The method for determining whether the parking position of the vehicle is accurate (whether a resonant current is output) includes: obtaining peak data of the main frequency and generating a main amplitude, obtaining peak data of the second largest amplitude of the AC data and generating a negative amplitude, and determining whether the difference between the main amplitude and the secondary amplitude exceeds a first preset threshold. If not, feedback is given that the vehicle position is incorrect; if yes, determining whether the main amplitude exceeds a second preset threshold. If not, feedback is given that the vehicle position is incorrect; if yes, feedback is given that the vehicle position is correct, and after charging is started, the control module outputs a resonant current.

[0054] Because the frequency of the receiving magnetic field generated by the receiving coil is directly controlled by the control module (active oscillation), there is a certain computational delay in the control module's reception and output of the resonant current. This causes the output resonant current to be out of sync with the oscillating current, affecting energy conversion efficiency. The control module incorporates a delay strategy to delay the output of the resonant current, ensuring that the transmitting and receiving magnetic fields oscillate synchronously at the same frequency.

[0055] Delay strategies include:

[0056] S1: Calculate the theoretical charging value based on the main amplitude to obtain the actual charging value of the battery;

[0057] S2: Determine whether the actual charging value is greater than the theoretical charging value. If not, delay the output time of the resonant current by N+1 delay periods, and loop step S2; if yes, stop the loop.

[0058] The delay period can be a set value. Each control chip is usually equipped with a crystal oscillator circuit. The crystal oscillator period is the minimum time period for the chip to operate. The crystal oscillator period can be used as the delay time. The delayed output time of the resonant circuit can be adjusted through multiple delays.

[0059] The delay period can also be obtained through the main frequency value, and the delay period value is less than (1 / main frequency) / x setting, where x is not less than 20 setting.

[0060] Because the resonant current delay is directly related to the hardware's response speed and performance, it's typically fixed. Once the delay is determined, the control module records the number of delays (the number of crystal oscillator cycles). The next time the car charges, the control module automatically controls the delay module to delay the vehicle by that number of times.

[0061] In actual use, in order to avoid resonance between one group of transmitting coils and only one group of receiving coils and to accurately transmit energy, the oscillating current frequencies flowing through the groups of transmitting coils on different charging parking spaces 2 are set differently.

[0062] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent.

Claims

1. A directional wireless charging method based on magnetic resonance technology, characterized in that: The invention comprises a resonance coil (103), wherein the resonance coil (103) receives magnetic energy of a transmitting magnetic field by means of magnetic induction and outputs a resonance current having the same frequency as the transmitting magnetic field, and the resonance current is input into a receiving coil to generate a receiving magnetic field having the same frequency as the transmitting magnetic field; The resonant coil (103) and the receiving coil are arranged on a vehicle, and a control module is electrically connected between the resonant coil (103) and the receiving coil. The control module is equipped with a common frequency strategy, including: collecting total current data output by the resonant coil, and outputting a number of periodically changing alternating current data through discrete Fourier transform; The frequency of the AC power data with the largest amplitude is obtained and a main frequency is generated, and the control module outputs a resonant current with the same main frequency; The resonant current output includes: obtaining peak data of the main frequency and generating a main amplitude, obtaining peak data of the second largest amplitude of the AC data and generating a negative amplitude, and determining whether the difference between the main amplitude and the secondary amplitude exceeds a first preset threshold, and if not, providing feedback indicating that the vehicle position is incorrect; If yes, it is determined whether the main amplitude exceeds a second preset threshold value; if not, feedback is given indicating that the vehicle position is incorrect; if yes, feedback is given indicating that the vehicle position is correct and charging begins, and the control module outputs a resonant current; The system includes a power module, the output end of the power module is electrically connected to a transmitting coil, the transmitting coil includes a first transmitting electrode (301) and a second transmitting electrode (302), and the receiving coil includes a first receiving electrode (101) and a second receiving electrode (102); The first emitter (301) and the second emitter (302) are arranged with opposite polarities, and the first receiver (101) and the second receiver (102) have coils with opposite rotation directions. The magnetic flux lines between the first emitter (301) and the second emitter (302) are along the length direction of the charging parking space (2); The resonant coil (103) is arranged between the first receiving pole (101) and the second receiving pole (102), and the axis of the resonant coil (103) is arranged along the length direction of the vehicle (1).

2. The directional wireless charging method based on magnetic resonance technology according to claim 1, characterized in that: The control module is equipped with a delay strategy, including: S1: Calculate the theoretical charging value based on the main amplitude and obtain the actual charging value of the battery; S2: Determine whether the actual charging value meets the theoretical charging value. If not, delay the output time of the resonant current by N+1 delay periods, and loop step S2. If yes, stop looping.

3. The directional wireless charging method based on magnetic resonance technology according to claim 2, characterized in that: The delay period is less than (1 / main frequency) / x, where x is not less than 20.

4. The directional wireless charging method based on magnetic resonance technology according to claim 1, characterized in that: The output end of the control module is connected to an indication module, and the indication module is composed of a plurality of indicator lights.

5. The directional wireless charging method based on magnetic resonance technology according to claim 1, characterized in that: The oscillating current frequencies corresponding to the transmitting coils of different charging parking spaces (2) are set differently.

6. The directional wireless charging method based on magnetic resonance technology according to claim 1, characterized in that: The control module and the indication module are both powered by the resonance coil (103).

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