Dual-resonance wireless power transmission system and method based on special receiving end coil

Abstract

The application provides a double-resonance wireless power transmission system and method based on a special receiving end coil, wherein the receiving end of the double-resonance wireless power transmission system based on the special receiving end coil comprises a receiving end circuit, a receiving end non-resonance coil and a receiving end resonance coil; the receiving end non-resonance coil is formed with a main contact point, the main contact point is electrically connected to a first end of the receiving end circuit, and the receiving end non-resonance coil is further formed with a plurality of auxiliary contact points with different numbers of turns from the main contact point; the system further comprises a control module for acquiring the distance between the receiving end and the transmitting end; and a switching module for adjusting the number of turns of the receiving end non-resonance coil according to the distance in a certain rule, wherein a first end of the switching module is electrically connected to a second end of the receiving end circuit, a second end of the switching module is switchably electrically connected to an auxiliary contact point, and a control end of the switching module is electrically connected to the control module. The application realizes high-efficiency wireless power transmission with free movement at a single working frequency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wireless power transmission, in particular to a double-resonance wireless power transmission system and method based on a special receiving-end coil. BACKGROUND

[0002] In the development of wireless power transmission system, there have been several stages. The first scheme directly generates an alternating electromagnetic field through a coil to achieve inductive coupling. Although this scheme (Qi standard) has been mass-produced, it has many disadvantages. On the one hand, the transmission distance is very short (not more than 10 mm), and on the other hand, the energy transmission efficiency is low (less than 50%), which leads to a small charging range. The magnetic resonance scheme proposed by Professor Marin of Massachusetts Institute of Technology can effectively improve the transmission distance of energy, but it also has obvious disadvantages. There is only one optimal working distance, and the transmission efficiency will decrease greatly at other distances. Based on the magnetic resonance transmission scheme, the engineering solution is to track the optimal working frequency. This method not only has difficulty in circuit design, but also cannot expand the charging range. In particular, in some specific scenarios, the improvement space of the transmitting-end circuit and coil system is limited (for example, small portable power supply devices), and the efficiency and mobility can only be improved by the receiving-end. In addition, it is difficult to avoid the frequency splitting problem caused by near-field interaction at a relatively short distance in the prior art.

[0003] Therefore, it is necessary to provide a scheme to solve the problems of short transmission distance, low transmission efficiency, small charging range and unstable working frequency in the existing wireless power transmission system. SUMMARY

[0004] In order to solve the problems of short transmission distance, low transmission efficiency and small charging range in the existing wireless power transmission system, the present application provides a double-resonance wireless power transmission system and method based on a special receiving-end coil.

[0005] The double-resonance wireless power transmission system based on a special receiving-end coil provided by the present application, the receiving end of the system includes a receiving-end circuit, a receiving-end non-resonant coil and a receiving-end resonant coil, the receiving-end non-resonant coil is electrically connected to the receiving-end circuit, the receiving-end resonant coil is coupled to the receiving-end non-resonant coil, the receiving-end non-resonant coil is formed with a main contact point, the main contact point is electrically connected to a first end of the receiving-end circuit, and the receiving-end non-resonant coil is also formed with a plurality of auxiliary contact points different in number of turns from the main contact point.

[0006] The double-resonance wireless power transmission system based on a special receiving-end coil further comprises:

[0007] A control module for obtaining the distance between the receiver and transmitter of the system;

[0008] A switching module for adjusting the number of turns of the non-resonant coil of the receiving end according to a certain rule based on the distance, wherein the first end of the switching module is electrically connected to the second end of the receiving end circuit, the second end of the switching module is switchably electrically connected to a secondary contact, and the control end of the switching module is electrically connected to the control module.

[0009] This invention achieves high-efficiency, free-moving wireless power transmission at a single operating frequency by switching between different contacts based on a specially wound receiving coil in a dual-resonance system. This meets the requirements of wireless power transmission systems for higher charging power and efficiency, satisfies the need for free movement, overcomes the difficulties of frequency tracking, solves the problem of the inability to optimize coils and circuits at the transmitting end, and does not increase the number of coils, thus achieving maximum material and space savings.

[0010] A further improvement of the present invention on the dual-resonance wireless power transmission system based on a special receiving coil is that the relationship between the number of turns of the non-resonant coil at the receiving end and the distance is negatively correlated.

[0011] A further improvement of the present invention on the dual-resonance wireless power transmission system based on a special receiving coil is that the control module controls the switching module to adjust the number of turns of the non-resonant coil at the receiving end, so that the resonance mode of the system is locked at the intrinsic frequency of the resonant coil at the receiving end.

[0012] A further improvement of the present invention on the dual-resonance wireless power transmission system based on a special receiving coil is that the transmitting end includes a transmitting resonant coil, a transmitting non-resonant coil, and a transmitting circuit. The transmitting resonant coil is resonantly coupled to the receiving resonant coil, the transmitting non-resonant coil is coupled to the transmitting resonant coil, and the transmitting circuit is electrically connected to the transmitting non-resonant coil.

[0013] A further improvement of the present invention on the dual-resonant wireless power transmission system based on a special receiving coil is that the magnetic field of the receiving resonant coil is coupled to the receiving non-resonant coil.

[0014] The magnetic field of the transmitting end resonant coil is coupled to the transmitting end non-resonant coil.

[0015] A further improvement of the present invention on the dual-resonance wireless power transmission system based on a special receiving coil is that the control module is electrically connected to the non-resonant coil of the receiving end.

[0016] A further improvement of the present invention on the dual-resonance wireless power transmission system based on a special receiving coil is that the control module includes a microcontroller, the switching module includes a controllable switch, and the control module is electrically connected to the control terminal of the switching module via a wire.

[0017] Furthermore, the present invention also provides a method for transmitting electrical energy using the above-mentioned dual-resonance wireless power transmission system based on a special receiving coil, wherein the control module executes the following steps:

[0018] Obtain the distance between the receiver and the transmitter;

[0019] According to the distance, the switching module is electrically connected to a pair of contacts in a certain way. The way is that the number of turns of the non-resonant coil at the receiving end and the distance are negatively correlated.

[0020] A further improvement of the dual-resonance wireless power transmission method of the present invention is that, in the step of controlling the switching module to be electrically connected to a pair of contacts according to a certain rule based on the distance: by adjusting the number of turns of the non-resonant coil at the receiving end, the resonant mode of the system is locked at the intrinsic frequency of the resonant coil at the receiving end.

[0021] A further improvement of the dual-resonance wireless power transmission method of the present invention is that the step of obtaining the distance between the transmitting end and the receiving end includes:

[0022] Detect the output current and voltage parameters of the receiving circuit;

[0023] The output current and voltage parameters are processed, and the distance is calculated based on the output current and voltage parameters. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the energy transmission relationship of a dual-resonance wireless power transmission system based on a special receiving coil, according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the main structure of a dual-resonance wireless power transmission system based on a special receiving coil according to an embodiment of the present invention.

[0026] Figure 3 A schematic diagram of the structure of the non-resonant coil at the receiving end in a dual-resonant wireless power transmission system based on a special receiving end coil according to an embodiment of the present invention.

[0027] Figure 4 This is a flowchart of a dual-resonance wireless power transfer method according to an embodiment of the present invention.

[0028] Figure 5a This is a schematic diagram of the system structure when the receiver is located in spatial region I and the access coil of the first auxiliary contact is coupled to the resonant coil of the receiver.

[0029] Figure 5b This is a schematic diagram showing the relationship between energy transmission efficiency and distance when the access coil of the first auxiliary contact is coupled to the resonant coil of the receiving end.

[0030] Figure 6a This is a schematic diagram of the system structure when the receiver is located in spatial region II and the access coil of the second auxiliary contact is coupled to the resonant coil of the receiver.

[0031] Figure 6b This is a schematic diagram showing the relationship between energy transmission efficiency and distance when the access coil of the second auxiliary contact is coupled to the resonant coil of the receiving end.

[0032] Figure 7a This is a schematic diagram of the system structure when the receiver is located in spatial region III and the access coil of the third auxiliary contact is coupled to the resonant coil of the receiver.

[0033] Figure 7b This is a schematic diagram showing the relationship between energy transmission efficiency and distance when the access coil of the third auxiliary contact is coupled to the resonant coil of the receiving end.

[0034] Figure 8 This is a schematic diagram showing the relationship between energy transmission efficiency and distance for a dual-resonance wireless power transmission system based on a special receiving coil, according to an embodiment of the present invention. Detailed Implementation

[0035] To address the problems of short transmission distance, low transmission efficiency, and small charging range in existing wireless power transmission systems, this invention provides a dual-resonance wireless power transmission system and method based on a special receiving coil.

[0036] The present invention, a dual-resonance wireless power transmission system and method based on a special receiving coil, will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0037] Combination Figures 1 to 3 As shown, the present invention is a dual-resonance wireless power transmission system based on a special receiving coil. The receiving end of the system includes a receiving circuit 70, a receiving non-resonant coil 60, and a receiving resonant coil 50. The receiving non-resonant coil 60 is electrically connected to the receiving circuit 70, and the receiving resonant coil 50 is coupled to the receiving non-resonant coil 60. The receiving non-resonant coil forms a main contact, which is electrically connected to the first end of the receiving circuit. The receiving non-resonant coil also forms multiple secondary contacts with different numbers of coil turns from the main contact.

[0038] The dual-resonance wireless power transfer system based on a special receiver coil also includes:

[0039] A control module (not shown in the figure) is used to obtain the distance between the receiver and transmitter of the system;

[0040] A switching module (not shown in the figure) is used to adjust the number of turns of the non-resonant coil of the receiving end according to a certain rule based on the distance. The first end of the switching module is electrically connected to the second end of the receiving end circuit. The second end of the switching module is switchably electrically connected to a pair of contacts. The control end of the switching module is electrically connected to the control module.

[0041] In this invention, by changing the number of turns of the receiving non-resonant coil 60 coupled to the receiving resonant coil 50, the magnetic flux between the receiving non-resonant coil 60 and the receiving resonant coil 50 is changed, and the channel coupling rate between the receiving non-resonant coil 60 and the receiving resonant coil 50 is changed, thereby optimizing and improving the energy transmission efficiency between the transmitting resonant coil 40 and the receiving resonant coil 50.

[0042] Specifically, when the distance between the transmitter and receiver changes, the number of turns of the non-resonant coil at the receiver is adjusted according to a certain pattern to adapt to the current distance, so that the energy transmission efficiency remains relatively stable and always within a relatively high range, thus solving the technical problems of short transmission distance, low transmission efficiency, and small charging range in the existing technology.

[0043] The present invention adjusts the non-resonant coil of the receiving end by setting multiple contacts on a non-resonant coil 60 at the receiving end, and selecting different contacts to select different numbers of coil turns. In this embodiment, the first end of the switching module is electrically connected to the receiving end circuit 70, and the second end of the switching module is electrically connected to a pair of contacts in the non-resonant coil 60 at the receiving end. That is, the receiving end circuit 70 connects or disconnects from the non-resonant coil 60 at the receiving end through the on or off state of the switching module. The control end of the switching module is electrically connected to and controlled by the control module. The control module selects a secondary contact corresponding to the current distance and controls the second end of the switching module to be electrically connected to the selected secondary contact, realizing the electrical connection between the secondary contact and the coil at the receiving end circuit 70, so that the coil is coupled to the receiving end resonant coil 50. When the distance changes, the control module selects another secondary contact and controls the second end of the switching module to switch the connection, ensuring that the receiving end circuit 70 is electrically connected to the secondary contact corresponding to the current distance, and ensuring that the receiving end resonant coil 50 is coupled to the coil corresponding to the current distance. The technical means of this invention are not limited to this; as long as it can ensure that the receiving end resonant coil 50 is coupled to the coil corresponding to the current distance (the receiving end circuit 70 is electrically connected to the secondary contact corresponding to the current distance), it is acceptable. This invention, based on a special receiving end coil, provides a dual-resonance wireless power transmission system without increasing the number of coils, thus achieving maximum material and space savings.

[0044] In this embodiment, the control module calculates the distance based on relevant circuit parameters; the control module is also electrically connected to the switching module for controlling the switching module; the switching module is electrically connected between the receiving circuit 70 and the receiving non-resonant coil 60. In other embodiments, the distance can be obtained through a distance sensor, and the number of turns of the receiving non-resonant coil 60 can be adjusted by changing the number of coil turns through a sliding switch.

[0045] Furthermore, the relationship between the number of turns of the non-resonant coil 60 at the receiving end and the distance is negatively correlated.

[0046] In this invention, when the distance increases, the number of turns of the non-resonant coil 60 at the receiving end is reduced to maintain the stability of the power transmission efficiency; when the distance decreases, the number of turns of the non-resonant coil 60 at the receiving end is increased to maintain the stability of the power transmission efficiency.

[0047] Furthermore, the control module controls the switching module to adjust the number of turns of the non-resonant coil 60 at the receiving end so that the resonance mode of the system is locked at the intrinsic frequency of the resonant coil 50 at the receiving end.

[0048] Based on the principle of parity-time (PT) symmetric non-Hermitian physical systems, adjusting the number of turns of the non-resonant coil 60 at the receiving end can avoid the splitting effect of the resonant frequency caused by near-field coupling, and keep the resonant mode of the system locked at the eigenfrequency of the two resonant coils, thereby maximizing the energy transfer efficiency.

[0049] Specifically, in a non-Hermitian physical system, the real part of the eigenvalue represents the frequency of the system mode, while the presence of an imaginary part indicates losses in the system mode. If the eigenvalue is purely real, the system mode efficiency is maximized. Energy transfer efficiency is maximized when the system operating frequency is the same as the real part of the system's eigenvalue frequency (i.e., the system's resonant mode). In existing power transmission systems, the system's resonant mode changes with distance and the number of turns in the receiving end's non-resonant coil 60. In this embodiment of the invention, by adjusting the number of turns in the receiving end's non-resonant coil 60, the influence of distance on the system's resonant mode (especially mode splitting) is offset, keeping the real part of the system's resonant mode constant (maintaining it near the eigenfrequency of the receiving end's resonant coil 50), and successfully eliminating the imaginary part of the resonant mode eigenvalue, thereby maximizing energy transfer efficiency at a single frequency.

[0050] The intrinsic frequency of the receiver resonant coil 50 is the same as the intrinsic frequency of the transmitter resonant coil 40. Those skilled in the art can obtain the required number of turns of the receiver non-resonant coil (to lock the system's resonant mode at the intrinsic frequency of the resonant coil) through circuit design and programming using conventional techniques.

[0051] Furthermore, regarding the efficiency issue caused by frequency splitting, traditional solutions require identical impedances at the receiver and transmitter, and the splitting frequency (resonance mode) must be identified as the system's operating frequency. This invention, by adjusting the non-resonant coil 60 at the receiver, ensures the system operates near its intrinsic mode in every spatial region, maximizing energy transfer efficiency. This invention guarantees a stable operating frequency at a single frequency simply by adjusting the non-resonant coil at the receiver, avoiding the complex circuit topology of frequency tracking and switching. It eliminates the need for simultaneous adjustments at both the transmitter and receiver to achieve optimal power supply efficiency, locks the intrinsic mode of the resonant coil, and improves system stability. This invention eliminates frequency splitting, ensuring operation at the coil's resonant frequency, thus solving the problem of unstable operating frequency in existing technologies.

[0052] Furthermore, the transmitting end includes a transmitting end resonant coil 40, a transmitting end non-resonant coil 30, and a transmitting end circuit 20. The transmitting end resonant coil 40 is resonantly coupled to the receiving end resonant coil 50, the transmitting end non-resonant coil 30 is coupled to the transmitting end resonant coil 40, and the transmitting end circuit 20 is electrically connected to the transmitting end non-resonant coil 30.

[0053] Figure 1 The diagram shows the overall block diagram of a dual-resonance wireless power transfer system based on a special receiving coil. The DC input terminal 10 inputs electrical energy to the transmitting circuit 20. This input energy is converted into a high-frequency AC signal by the transmitting circuit 20 and enters the transmitting non-resonant coil 30. From there, it is coupled into the transmitting resonant coil 40. The transmitting resonant coil 40 and the receiving resonant coil 50 then resonate and wirelessly transmit the energy to the receiving resonant coil 50. The receiving non-resonant coil 60 then extracts the energy from the receiving resonant coil 50, and finally, the energy is supplied to the load device 80 via the receiving circuit 70 (e.g., a filter and voltage regulator circuit). The two ends of the transmitting circuit 20 are electrically connected to the two ends of the transmitting non-resonant coil 30, and the two ends of the receiving circuit 70 are electrically connected to the two ends of the receiving non-resonant coil 60.

[0054] Furthermore, both the receiver resonant coil 50 and the transmitter resonant coil 40 are independent closed loops.

[0055] In this embodiment, the receiving end resonant coil 50 and the transmitting end resonant coil 40 are simply composed of wound coils and several low-loss capacitors connected in parallel.

[0056] Furthermore, the magnetic field of the receiving end resonant coil 50 is coupled to the receiving end non-resonant coil 60; the magnetic field of the transmitting end resonant coil 40 is coupled to the transmitting end non-resonant coil 30.

[0057] In this embodiment, the receiving resonant coil 50 forms a self-closing loop, using only low-loss NPO capacitors and a suitable coil design. The receiving non-resonant coil 60 and the receiving resonant coil 50 are coupled through a magnetic field, effectively improving the Q value of the receiving resonant coil 50. Similarly, the transmitting resonant coil 40 forms a self-closing loop, using only low-loss NPO capacitors and a suitable coil design. The transmitting non-resonant coil 30 and the transmitting resonant coil 40 are coupled through a magnetic field, effectively improving the Q value of the transmitting resonant coil 40. This wireless power transmission system can maximize the energy transmission distance.

[0058] Furthermore, the distance is the distance between the receiving end resonant coil 50 and the transmitting end resonant coil 40.

[0059] Furthermore, the control module is electrically connected to the non-resonant coil 40 at the receiving end.

[0060] In this embodiment, the control module is electrically connected to the non-resonant coil 60 at the receiving end, and calculates the distance based on the relevant circuit parameters in the non-resonant coil 60 at the receiving end.

[0061] Furthermore, the control module includes: a detection unit (not shown in the figure) for detecting the output current and voltage parameters of the receiving circuit 70, the detection unit being electrically connected to the receiving circuit 70; a calculation unit (not shown in the figure) for processing the output current and voltage parameters and calculating the distance based on the output current and voltage parameters, the calculation unit being electrically connected to the detection unit; and a control unit (not shown in the figure) for controlling the switching module based on the distance, the control unit being electrically connected to the calculation unit and the switching module.

[0062] The coupling strength between the transmitting resonant coil 40 and the receiving resonant coil 50 varies at different distances. This embodiment utilizes this characteristic to obtain the distance by monitoring and analyzing the output current and voltage parameters of the receiving circuit 70. The output current and voltage refer to the current and voltage output from the receiving circuit 70 to the load device 80; that is, the output voltage and current parameters are the voltage and current on the load, which are DC. This invention is not limited to this; any method that can obtain the distance between the transmitting resonant coil 40 and the receiving resonant coil 50 is acceptable.

[0063] Specifically, by setting voltage and current probes (Hall elements or resistor dividers) on the load device 80, the detected voltage (Uin) and current (Iin) values ​​are stepped down and input to the receiving Bluetooth module (containing an MCU); similarly, voltage and current probes are set on the transmitting DC input terminal 10, and the detected voltage (Uout) and current (Iout) values ​​are stepped down and input to the transmitting Bluetooth module (containing an MCU); the transmitting Bluetooth module then transmits the data to the receiving Bluetooth module; the MCU of the receiving Bluetooth module can then calculate the energy transfer efficiency η = (Uin / Iout) * Iout * Iout.out I out ) / (U in I in By switching between different receiver non-resonant coils 60, the receiver non-resonant coil 60 with the highest energy transmission is finally selected to work.

[0064] Furthermore, the control module is a microcontroller module, and the switching module includes a controllable switch.

[0065] In this embodiment, the switching module includes a controllable switching device; a microcontroller unit (MCU) detects and processes output current and voltage parameters and obtains the distance; then the MCU controls and drives the switching device. In other embodiments, a 5V electronic switch can be used in the signal switch (low voltage) circuit; a relay can be used in the MOS switch (high voltage) circuit. Switching different coils may require simultaneously switching the MOS gate drive signal and the MOS transistor input voltage to ensure complete circuit switching.

[0066] Furthermore, the relationship between the number of turns of the non-resonant coil 60 at the receiving end and the distance is negatively correlated.

[0067] In this invention, when the distance increases, the number of turns of the non-resonant coil 60 at the receiving end is reduced to maintain the stability of the power transmission efficiency; when the distance decreases, the number of turns of the non-resonant coil 60 at the receiving end is increased to maintain the stability of the power transmission efficiency.

[0068] In addition, combined Figure 3 As shown, the present invention also provides a method for power transmission using the above-described dual-resonance wireless power transmission system based on a special receiving coil, wherein the control module executes the following steps:

[0069] Step S101: Obtain the distance between the receiver and the transmitter;

[0070] Step S102: Control the switching module to be electrically connected to a pair of contacts according to a certain pattern based on the distance.

[0071] Further, step S101 includes:

[0072] Detect the output current and voltage parameters of the non-resonant coil 60 at the receiving end;

[0073] The output current and voltage parameters are processed and the distance is calculated based on these parameters. The pattern is that the number of turns of the non-resonant coil at the receiving end and the distance are negatively correlated.

[0074] Furthermore, in the step of controlling the switching module to be electrically connected to a pair of contacts according to a certain rule based on the distance: by adjusting the number of turns of the non-resonant coil 60 at the receiving end, the resonant mode of the system is locked at the intrinsic frequency of the resonant coil 50 at the receiving end.

[0075] Furthermore, the step of obtaining the distance between the transmitter and receiver includes: detecting the output current and voltage parameters of the receiver circuit 70; processing the output current and voltage parameters and calculating the distance based on the output current and voltage parameters.

[0076] Furthermore, the distance is the distance between the receiving end resonant coil 50 and the transmitting end resonant coil 40.

[0077] Combination Figure 2 , Figures 5a to 8 As shown, in this embodiment, the dual-resonance wireless power transmission system based on a special receiving coil includes a receiving resonant coil 50, a receiving non-resonant coil 60, and a transmitting resonant coil 40 and a transmitting non-resonant coil 30. The receiving non-resonant coil 60 forms four contacts, including a main contact C0, a first auxiliary contact C1, a second auxiliary contact C2, and a third auxiliary contact C3. The main contact C0 is always connected to the first terminal of the receiving circuit 70. The first auxiliary contact C1, the second auxiliary contact C2, and the third auxiliary contact C3 are tapped from the receiving non-resonant coil 60 to become selectable contacts. The selected contacts represent the number of turns of the receiving end non-resonant coil 60 in the connected system, with C1 having the fewest, C2 the next, and C3 the most. The second terminal of the receiving end circuit 70 is electrically connected to one of the first pair of contacts C1, the second pair of contacts C2, and the third pair of contacts C3. The signal flowing through the receiving end non-resonant coil 60 is a high-frequency AC signal generated by the receiving end circuit 70, with an operating frequency of a single frequency between 50kHz and 10MHz. The output signal of the transmitting end non-resonant coil 30 is a high-frequency AC signal, which can be used after passing through the downstream transmitting end circuit 20 (including a rectifier circuit and a filter circuit). The third pair of contacts C3, the second pair of contacts C2, and the first pair of contacts C1 correspond to spatial regions I, II, and III, respectively. The distance from spatial region I to the receiving end is less than the distance from spatial region II to the receiving end, and the distance from spatial region II to the receiving end is less than the distance from spatial region III to the receiving end.

[0078] The receiving end resonant coil 50 and the transmitting end resonant coil 40 have the same resonant frequency ω0, which is the operating frequency in this invention. This frequency ω0 is usually between 50kHz and 10MHz, and the specific value is related to the overall size and operating environment of the dual resonant wireless power transmission system based on the special receiving end coil.

[0079] Specifically, when the receiver moves as a whole in space, it continuously switches the non-resonant coil 60 connected to the system to achieve high-efficiency, single-frequency, and freely movable power transmission. For example, when the receiver is in a relatively close spatial region I, the system switches to the third contact C3 with more winding turns, such as... Figure 5a As shown, the system's efficiency at its intrinsic frequency ω0 is as follows:Figure 5b As shown, it can be observed that the number of coil turns connected to the third contact C3 can provide high-efficiency single-frequency mobile power transmission within spatial region I.

[0080] If the receiver is moved to space region II, the number of coil turns connected to the original third contact C3 will be insufficient. In this case, switch to the second contact C2, as follows: Figure 6a As shown. The number of turns connected to the second contact C2 is less than the number of turns connected to the third contact C3. The relationship between the energy transfer efficiency and the spatial area when the second contact C2 is activated is as follows. Figure 6b As shown. The number of turns connected to the second auxiliary contact C2 is to provide single-frequency high-efficiency mobile power transmission within spatial region II.

[0081] If the receiver is moved to space region III, the number of access turns of the original second contact C2 will not be sufficient. In this case, switch to the first contact C1, as follows: Figure 7a As shown. The number of turns connected to the first contact C1 is less than the number of turns connected to the second contact C2. The relationship between the energy transfer efficiency and the spatial area when the first contact C1 is activated is as follows. Figure 7b As shown. The number of turns connected to the first auxiliary contact C1 can provide single-frequency high-efficiency mobile power transmission within spatial region III.

[0082] In summary, as Figure 8 As shown, this scheme achieves efficient power transmission over a large spatial region (space region I, space region II, and space region III) by switching the coupling operation of the secondary contacts C1, C2, and C3 of the specially wound receiving non-resonant coil 60 with the receiving resonant coil 50. Furthermore, the system constructed using this scheme achieves a single operating frequency, which greatly simplifies the transmitting circuit 20 that outputs high-frequency AC signals. This scheme is of significant importance in the engineering implementation of wireless power transmission systems. The above is merely one embodiment of the present invention; the number of secondary contacts, the number of coil turns connected to the secondary contacts, and the applicable spatial region are not limited to the above embodiment.

[0083] In existing technologies, energy transmission efficiency gradually decreases with increasing distance. This invention changes the number of turns of the receiving end non-resonant coil 60 by switching contacts, thereby controlling the magnetic flux of the receiving end non-resonant coil 60 and the receiving end resonant coil 50, achieving stable and efficient energy transmission over a wide range. This invention can operate at a single frequency. By changing the number of turns of the receiving end non-resonant coil 60, this invention ensures that the operating frequency remains consistent (i.e., it ensures operation at the coil's resonant frequency).

[0084] This invention can be applied to various angles (generally 0° to 60°), to wireless charging systems with different area ratios, and even in extreme cases such as unequal coil area ratios, unequal spatial angles, and misaligned relative positions, ensuring relatively stable energy transfer efficiency over a large area. In practical applications, the number of coil turns needs to be designed according to different application scenarios.

[0085] This invention achieves high-efficiency, free-moving wireless power transmission at a single operating frequency by switching between different contacts based on a specially wound receiving coil in a dual-resonance system. This meets the requirements of wireless power transmission systems for higher charging power and efficiency, satisfies the need for free movement, overcomes the difficulty of frequency tracking, and solves the problem of not being able to optimize the transmitting circuit and coil in the miniaturization requirements of the transmitting end.

[0086] This invention changes the number of turns of the non-resonant coil 60 at the receiving end by switching the secondary contacts of the specially wound receiving end non-resonant coil 60, thereby altering the distribution of the magnetic field from a physical mechanism, which can effectively improve the energy transmission efficiency; it can stabilize the operating frequency of the system at a single frequency; it can provide a larger charging range to meet the needs of free movement; and it does not increase the number of coils in the dual-resonant four-coil system, achieving maximum material and space savings.

[0087] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

[0088] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

Claims

1. A wireless power transmission system based on a special receiving end coil, the receiving end of the system comprising a receiving end circuit, a receiving end non-resonant coil and a receiving end resonant coil, the receiving end non-resonant coil being electrically connected to the receiving end circuit, and the receiving end resonant coil being coupled to the receiving end non-resonant coil, characterized in that: the receiving end non-resonant coil is formed with a main contact point, the main contact point being electrically connected to a first end of the receiving end circuit, and the receiving end non-resonant coil is further formed with a plurality of secondary contact points having different numbers of turns from the main contact point; the wireless power transmission system based on the special receiving end coil further comprises: a switching module, a first end of the switching module being electrically connected to a second end of the receiving end circuit, and a second end of the switching module being switchably electrically connected to one of the secondary contact points; and a control module, the control module being electrically connected to a control end of the switching module, and when the receiving end as a whole moves in space, the control module acquires a distance between the receiving end and a transmitting end of the system, and controls the switching module to constantly switch the receiving end non-resonant coil connected to the system according to the distance in a certain rule, so as to achieve single-frequency high-efficiency power transmission; wherein the control module controls the switching module to adjust the number of turns of the receiving end non-resonant coil, so that the system still has a relatively high energy transmission efficiency in a resonant mode locked at an intrinsic frequency of the receiving end resonant coil. The rule is that the number of turns of the receiving end non-resonant coil and the distance are negatively correlated. The transmitting end comprises a transmitting end resonant coil, a transmitting end non-resonant coil and a transmitting end circuit, the transmitting end resonant coil being resonantly coupled to the receiving end resonant coil, the transmitting end non-resonant coil being coupled to the transmitting end resonant coil, and the transmitting end circuit being electrically connected to the transmitting end non-resonant coil. The receiving end resonant coil is magnetically coupled to the receiving end non-resonant coil. The transmitting end resonant coil is magnetically coupled to the transmitting end non-resonant coil. The control module is electrically connected to the receiving end non-resonant coil.

2. The dual-resonance wireless power transfer system based on a special receiver coil of claim 1, characterized in that: The control module comprises a single-chip microcomputer, the switching module comprises a controllable switch, and the control module is electrically connected to the control end of the switching module through a wire.

3. The dual-resonance wireless power transfer system based on a special receiver coil of claim 1, wherein: When the receiving end as a whole moves in space, the following steps are performed by the control module:

4. The dual-resonance wireless power transfer system based on a special receiver coil of claim 3, characterized in that: acquiring the distance between the receiving end and the transmitting end; and controlling the switching module to be electrically connected to one of the secondary contact points according to the distance in a certain rule, so as to achieve single-frequency high-efficiency power transmission by constantly switching the receiving end non-resonant coil connected to the system, the rule being that the number of turns of the receiving end non-resonant coil and the distance are negatively correlated; wherein 5. The dual-resonance wireless power transfer system based on a special receiver coil of claim 1, wherein: in the step of controlling the switching module to be electrically connected to one of the secondary contact points according to the distance in a certain rule, the number of turns of the receiving end non-resonant coil is adjusted, so that the system still has a relatively high energy transmission efficiency in a resonant mode locked at an intrinsic frequency of the receiving end resonant coil.

6. The dual-resonance wireless power transfer system based on a special receiver coil of claim 1, wherein: The step of acquiring the distance between the transmitting end and the receiving end comprises:

7. A method of power transmission using the dual-resonance wireless power transfer system based on a special receiver coil according to claim 1, characterized in that, detecting output current and voltage parameters of the receiving end circuit; and ​ ​ ​ 8. The method of claim 7, wherein, ​ ​ processing the output current voltage number parameter and calculating the distance from the output current voltage number parameter.

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