Wireless electric energy transmitting device and transmission system based on multiple coaxial transmitting coils

Abstract

The invention provides a wireless electric energy transmitting device and transmission system based on multiple coaxial transmitting coils, and the device comprises a plurality of transmitting modules, and each transmitting module comprises a transmitting coil, a transmitting side compensation network, and a transmitting side converter which are connected in sequence; the multi-converter control module is connected with the transmitting side converter and is used for generating a control signal of the transmitting side converter based on the inductance parameter of the transmitting coil so as to control the output voltage of the transmitting side converter; and the output voltage is compensated by the transmitting side compensation network and then is provided for the transmitting coil, so that the transmitting coil works under the condition of maximum wireless power transmission efficiency.

Description

Technical Field

[0001] The present disclosure relates to the field of wireless power transmission, and in particular, to a wireless power transmission device and a transmission system based on coaxial multiple transmitting coils. Background Art

[0002] Existing wireless power transmission technologies have low transmission power and efficiency, which are not conducive to long-distance wireless power transmission, and have large occupied space and high cost. Summary of the Invention

[0003] The present disclosure proposes a wireless power transmission device based on coaxial multiple transmitting coils to solve the above technical problems to a certain extent.

[0004] In a first aspect of the present disclosure, there is provided a wireless power transmitting device based on coaxial multiple transmitting coils, including:

[0005] A plurality of transmitting modules, each of the transmitting modules includes a transmitting coil, a transmitting-side compensation network, and a transmitting-side converter connected in sequence;

[0006] A multi-converter control module, connected to the transmitting-side converter, for generating a control signal of the transmitting-side converter based on the inductance parameter of the transmitting coil to control the output voltage of the transmitting-side converter; the output voltage is compensated by the transmitting-side compensation network and then provided to the transmitting coil, so that the transmitting coil operates under the condition of maximum wireless power transmission efficiency.

[0007] In a second aspect of the present disclosure, there is provided a wireless power transmission system based on coaxial multiple transmitting coils, including:

[0008] The wireless power transmitting device based on coaxial multiple transmitting coils as described in the first aspect;

[0009] And a wireless power receiving device, configured to receive the electric energy transmitted from the wireless power transmitting device and provide it to a load.

[0010] As can be seen from the above, the wireless power transmitting device and the transmission system based on coaxial multiple transmitting coils provided by the present disclosure adopt a multi-transmitting module design for the wireless power transmitting device with coaxial multiple transmitting coils. Each transmitting module is composed of a transmitting coil, a transmitting-side compensation network, and a transmitting-side converter connected in sequence. The multi-converter control module is connected to the transmitting-side converter to generate a control signal according to the inductance parameter of the transmitting coil to regulate the output voltage of the converter. This voltage is adjusted by the compensation network and then supplied to the transmitting coil to ensure that each coil operates under the condition of maximum wireless power transmission efficiency. It can improve the transmission efficiency of the wireless power transmission system, ensure that the wireless power transmission always maintains the optimal transmission efficiency, thereby enhancing the adaptability and stability of the wireless power transmission. Brief Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions in the present disclosure or related technologies, the following will briefly introduce the drawings required for use in the embodiments or the description of related technologies. Obviously, the drawings in the following description are only the embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0012] Figure 1 Schematic diagram of wireless power transmission using a single transmitting coil in related technologies.

[0013] Figure 2 Schematic diagram of wireless power transmission using a relay coil in related technologies.

[0014] Figure 3 Schematic diagram of a wireless power transmission system based on coaxial multi-transmitting coils according to an embodiment of the present disclosure.

[0015] Figure 4 Schematic diagram of a wireless power transmitting device based on coaxial multi-transmitting coils according to an embodiment of the present disclosure. Detailed Description of the Embodiments

[0016] To make the objectives, technical solutions, and advantages of the present disclosure more clear and understandable, the following further details the present disclosure in conjunction with specific embodiments and with reference to the accompanying drawings.

[0017] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure pertains. The "first", "second", and similar terms used in the embodiments of the present disclosure do not indicate any order, quantity, or importance, but are only used to distinguish different components. The terms such as "include" or "comprise" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connect" or "couple" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0018] With the development of wireless power transfer technology and the continuous expansion of application scenarios, there has gradually emerged a need to increase the wireless power transfer distance. For example, in the dynamic wireless charging of smart homes and the like, to provide convenient wireless charging, higher requirements are put forward for the wireless power transfer distance, and it is desired to save the space of the transmission path. At the same time, the position of the charging device is not fixed, which in turn affects the coupling situation of the system.

[0019] In related technologies, a double coil can be used for long-distance wireless power transfer, such as Figure 1 shown. Figure 1 Fig. shows a schematic diagram of wireless power transfer using a single transmitting coil in related technologies. The mutual inductance value between the two coils induced in the wireless charging system is not only related to the wire diameter, radius and number of turns of the two coils, but also depends on the axial distance between the two coils. The smaller the axial distance between the two coils, the larger the mutual inductance value; conversely, the larger the axial distance between the two coils, the smaller the mutual inductance value. If a longer transmission distance is desired, with the conditions such as frequency and input voltage already determined, only by increasing the diameters of the transmitting coil and the receiving coil can the coupling between the receiving coil and the transmitting coil be increased, thereby achieving long-distance wireless power transfer. However, when using this method, the energy loss is large. Therefore, this method is limited by the current-carrying capacity of the coil itself, and the transmission efficiency is usually very low, which is not conducive to long-distance wireless power transfer.

[0020] In related technologies, a wireless power transfer system with a relay coil can also be used. By adding a relay coil in the transmission path, the wireless power transfer distance and transmission efficiency can be improved, such as Figure 2 shown. Figure 2 Fig. shows a schematic diagram of wireless power transfer using a relay coil in related technologies. The relay coil consists of a wound coil and a capacitor with good impedance matching to form a single independent coil loop. When resonance occurs, due to the addition of the relay coil, the same current can achieve electromagnetic conversion more times, strengthening the magnetic field intensity on the electromagnetic transmission path. This enhanced magnetic field can increase the induced current in the coil, thereby improving the transmission efficiency and transmission distance. However, although this method increases the wireless power transfer distance, the use of the relay coil occupies a large amount of space and is not suitable for occasions with high space requirements. Moreover, the relay coil is only used as an intermediate station for energy transfer, reducing the material utilization rate and increasing the cost. Therefore, the multi-coil wireless power transfer system using a relay coil occupies a large amount of intermediate space and is subject to certain limitations in realizing wireless power application scenarios such as smart homes.

[0021] Therefore, how to improve the transmission power and transmission efficiency of wireless power transmission while meeting requirements such as long-distance transmission, reducing occupied space, and lowering costs has become a technical problem that urgently needs to be solved.

[0022] In view of this, a wireless power transmission device and a transmission system based on coaxial multi-transmitting coils provided by the embodiments of the present disclosure adopt a multi-transmitting module design. Each transmitting module is composed of a transmitting coil, a transmitting-side compensation network, and a transmitting-side converter connected in sequence. The multi-converter control module is connected to the transmitting-side converter to generate a control signal according to the inductance parameter of the transmitting coil to regulate the output voltage of the converter. This voltage is supplied to the transmitting coil after being adjusted by the compensation network to ensure that each coil operates under the condition of maximum wireless power transmission efficiency. It can improve the transmission efficiency of the wireless power transmission system, ensure that the wireless power transmission always maintains the optimal transmission efficiency, thereby enhancing the adaptability and stability of the wireless power transmission.

[0023] See Figures 3 - 4 , Figures 3 - 4 shows a schematic diagram of a wireless power transmission system based on coaxial multi-transmitting coils according to an embodiment of the present disclosure. Figures 3 - 4 In, a wireless power transmission system based on coaxial multi-transmitting coils may include:

[0024] A wireless power transmission device based on coaxial multi-transmitting coils;

[0025] And a wireless power receiving device for receiving the electric energy transmitted from the wireless power transmission device and supplying it to a load.

[0026] Among them, a wireless power transmission system based on coaxial multi-transmitting coils may include a wireless power transmission device based on coaxial multi-transmitting coils and a wireless power receiving device. Specifically, as Figure 3 shown, a wireless power transmission device based on coaxial multi-transmitting coils may include a plurality of transmitting devices, and the transmitting coils of each transmitting device are arranged coaxially. Each transmitting coil adopts a separate LCC compensation network, and the series inductance and parallel capacitance in the compensation network may both be the same value, and the series capacitance may adopt a variable capacitance. Different transmitting devices may use the same DC power supply or separately use individual DC power supplies to provide energy. The wireless power receiving device may adopt an S compensation network topology structure, mainly composed of a receiving coil, a series compensation capacitor, and a load.

[0027] The wireless power transmission system based on coaxial multi-transmitting coils according to the embodiments of the present disclosure may adopt an LCC-S compensation network. This LCC-S compensation network utilizes the principle of magnetic coupling resonance to realize wireless power transmission by adjusting the circuit parameters at the transmitting end and the receiving end. "LCC" may refer to the combination of an inductor (L), a capacitor (C), and another capacitor (C) to form a resonant circuit; "S" may refer to the series compensation network on the receiving side. The LCC compensation network connected to the transmitting coil in the coaxial multi-transmitting coil wireless power transmission system satisfies the resonant condition during operation.

[0028] In some embodiments, the wireless power receiving device includes:

[0029] A receiving coil for receiving the electric power;

[0030] A receiving-side compensation network connected to the receiving coil for compensating the electric power to offset the noise and loss during transmission;

[0031] A receiving-side converter connected to the receiving-side compensation network for converting the electric power and supplying it to a load.

[0032] Specifically, the power receiving device may include an S compensation topology and a rectifier, and the receiving end may adopt coils of any structure, including coils of types such as circular, square, and polygonal.

[0033] See Figure 3 , in a wireless power transmission system based on coaxial multi-transmitter coils, the coupling relationship between the n transmitter coils cannot be ignored, and the influence of the coupling between the transmitter coils in different situations needs to be considered. The mutual inductance between each transmitter coil is expressed as: M 12 , M 13 , M 14 , …, M 1n ; M 21 , M 23 , M 24 , …, M 2n ; …; M n1 , M n2 , M n3 , …, M nn-1 ; where M ij = M ji , i = 1, 2, 3, …, n, j = 1, 2, 3, …, n, and i ≠ j. The coaxial multi-transmitter wireless power transmission system contains n transmitter coils, and the transmitter coils are not arranged in a decoupled planar manner. Therefore, the influence of the coupling between the transmitter coils must be considered. The equivalent self-inductance parameters of each transmitter coil can be expressed as:

[0034]

[0035] In the formula, L eqi-t is the equivalent self-inductance of the i-th transmitter coil, and L i-t is the self-inductance of the i-th transmitter coil; U i is the equivalent voltage amplitude output by the i-th inverter, that is:

[0036]

[0037] where U dc is the voltage value of the DC voltage source; Taking the phase - shift angle of the control signal as an example, by changing the phase - shift angle, the equivalent amplitude of the output voltage of each inverter can be changed. This voltage formula is used as the basis for the subsequent module to adjust the current of each transmitting coil.

[0038] As Figure 3 shown, the centers of each transmitting coil are arranged coaxially, and each transmitting coil is connected to an independent compensation network and a converter to form a separate transmitting module. Each transmitting module is powered by a DC power supply, and there are two DC power supply methods: one is single - DC - source power supply. In this case, all transmitting modules are powered by the same DC power supply. When the series inductance and parallel capacitance of the compensation networks of each transmitting coil are the same, according to the formula, the U dc in the formula is the same value. Therefore, the current flowing into each transmitting coil can be controlled only by changing the phase - shift angle of the control signal, and the control method is relatively simple; the second is to use multiple DC power supplies to supply power to different transmitting modules respectively. If the output voltages of each DC power supply are the same, the control method is the same as the first one. If the output voltages of each DC power supply are different, then according to the formula, U dc is different. Therefore, when changing the current inside each transmitting coil, both U dc and the phase - shift angle of the control signal need to be considered.

[0039] In some embodiments, multiple transmitting coils can adopt the same design. For example, a planar coil structure can be used, and its structure type can be circular, square, polygonal, etc.

[0040] In some embodiments, in the transmitting - side compensation network of the transmitting coil, the series inductance and parallel capacitance can be designed according to different requirements. The series capacitor is a variable capacitor and can be changed in real - time according to different working conditions.

[0041] In some embodiments, the current flowing through each transmitting coil can be changed arbitrarily through control, and there is an optimal current distribution ratio. Under the optimal distribution ratio, the maximum wireless power transfer efficiency can be obtained.

[0042] In some embodiments, the distance between the transmitting coils can be adjusted arbitrarily.

[0043] In some embodiments, when the load or the distance between the transmitting device and the receiving device changes, it is possible to automatically adjust the current distribution inside each transmitting coil and automatically adjust the parameters of the compensation network, so that the wireless power transfer system can achieve the maximum transfer efficiency.

[0044] Referring to Figure 4 , Figure 4 shows a schematic diagram of the wireless power transfer system based on coaxial multi - transmitting coils according to an embodiment of the present disclosure. Figure 4 In

[0045] A plurality of transmitting modules, each of the transmitting modules including a transmitting coil, a transmitting-side compensation network, and a transmitting-side converter that are connected in sequence;

[0046] A multi-converter control module, connected to the transmitting-side converter, for generating a control signal for the transmitting-side converter based on the inductance parameter of the transmitting coil to control the output voltage of the transmitting-side converter; the output voltage is compensated by the transmitting-side compensation network and then provided to the transmitting coil so that the transmitting coil operates under the condition of maximum wireless power transfer efficiency.

[0047] Figure 4 Among them, the wireless power transfer system based on coaxial multi-transmitting coils includes: a power source, a transmitting-end power conversion device 101, a transmitting-end wireless power transfer compensation network 102, a transmitting-end wireless power transfer coil 103, a receiving-end wireless power transfer coil and compensation network, a receiving-end power conversion device, and a load. That is, the main body of the wireless power transfer system as shown in Figure 3 The transmitting-end power conversion device 101 includes a transmitting-end power converter 101-1, a transmitting-end power converter 101-2... a transmitting-end power converter 101-n. The transmitting-side compensation network 102 includes series variable capacitors 102-1 in the compensation network, series variable capacitors 102-2 in the compensation network... series variable capacitors 102-n in the compensation network as the main control devices; the transmitting-end wireless power transfer coil 103 is composed of a wireless power transfer coil 103-1, a wireless power transfer coil 103-2... a wireless power transfer coil 103-n. It should be understood that n here can be designed and selected according to different application conditions and is not limited here.

[0048] The wireless power transfer system based on coaxial multi-transmitting coils adopts an LCC-S compensation network. According to the characteristics of the LCC-S compensation network, the series inductance and parallel capacitance of each transmitting coil can adopt the same value, and the series inductance and parallel capacitance are ensured to resonate. At this time, if the same voltage is applied across each transmitting coil, the current flowing into each transmitting coil is the same. When different voltages are applied across each transmitting coil, the current flowing into each transmitting coil is positively correlated with the voltage value. Therefore, a control method of adjusting the equivalent voltage across each transmitting coil can be adopted to change the current inside each transmitting coil. Since each transmitting coil has an independent transmitting-end power converter, it can be regarded as having an independent power supply. And, the equivalent self-inductance of each transmitting coil is related to the current ratio of each transmitting coil. Therefore, the series capacitance of the LCC-S compensation network is a variable.

[0049] In some embodiments, the multi-converter control module includes:

[0050] A parameter real-time measurement module, connected to the transmitting coil, for detecting the inductance parameter of the transmitting coil;

[0051] A parameter calculation module, connected to the parameter real-time measurement module, for determining the phase shift angle of the control signal based on the inductance parameter;

[0052] A converter real-time control module, connected to the parameter calculation module, for generating the control signal based on the phase shift angle to control the output voltage of the transmitting side converter.

[0053] Specifically, as Figure 4 shown, the parameter real-time measurement module 104 can detect in real time the parameters required for calculation, such as the distance between each transmitting coil, the mutual inductance between each transmitting coil, and the mutual inductance between each transmitting coil and the receiving coil. In some embodiments, by using a storage module, the mutual inductance between each transmitting coil at different transmitting coil distances and the mutual inductance between the transmitting coil and the receiving coil can be stored in advance. The real-time measurement module directly and real-time calls the parameters from the storage module by detecting in real time the distance between each transmitting coil and the distance between the transmitting coil and the receiving coil. In some embodiments, the mutual inductance between the transmitting coils and the mutual inductance between the transmitting coil and the receiving coil can be directly measured by using real-time parameter measurement technology and other means. Finally, the parameter real-time measurement module 104 transmits the measured data to the optimal current distribution coefficient calculation module 105 and the multi-parameter real-time calculation module 106 to further process the measured parameters and prepare for the setting of subsequent control methods.

[0054] The optimal current distribution coefficient calculation module 105 can be a fast calculation module, and the main calculation principle formula inside it is the system transmission efficiency formula:

[0055]

[0056] where M ir is the mutual inductance between the i-th transmitting coil and the receiving coil; α i is the current coefficient flowing through the i-th transmitting coil, and satisfies that the sum of the current coefficients is 1, that is, α1 + α2 + … + α n = 1; R i is the internal resistance of the i-th transmitting coil, Z ref-i is the reflected impedance of the receiving coil at the i-th transmitting coil; R r is the internal resistance of the receiving coil; R L is the load resistance value. When the mutual inductance between the load, the transmitting coil, and the receiving coil changes, there will be different current distribution coefficients α i to make the transmission efficiency maximum.

[0057] According to the above formula for the transmission efficiency of the wireless power transmission system, the current coefficient α that maximizes the transmission efficiency η can be solved. i In some embodiments, a mathematical calculation method can be adopted, that is, the extreme value method of multivariate functions is used to solve the current distribution coefficient α. i The specific process is as follows:

[0058] (1) Calculate the first-order partial derivative of the wireless power transmission efficiency formula:

[0059]

[0060] (2) Solve αi at the maximum point, and retain the value of αi that satisfies the following conditions.

[0061]

[0062] (3) Substitute the obtained αi into the Hessian matrix. If it satisfies the negative definite condition, it is the optimal current distribution coefficient.

[0063]

[0064] In some embodiments, methods such as the Newton method, simulated annealing algorithm, genetic algorithm, ant colony algorithm, and particle swarm optimization algorithm can be used to directly solve the optimal current distribution coefficient. The above-mentioned various methods can all be used as the internal algorithms of the optimal current distribution coefficient calculation module 105 for solving the optimal current distribution coefficient, and the method can be selected according to different requirements. The optimal current distribution coefficient calculation module 105 sends the calculated optimal current distribution coefficient to the multi-parameter calculation module 106, and the data is further processed in the multi-parameter calculation module 106.

[0065] In some embodiments, the parameter calculation module includes:

[0066] An optimal current distribution coefficient calculation module, connected to the inductance parameter module, for calculating the current distribution coefficient of the transmitting coil corresponding to the maximum wireless power transmission efficiency based on the inductance parameter;

[0067] A multi-parameter real-time calculation module, connected to the optimal current distribution coefficient calculation module, for calculating the phase shift angle based on the current distribution coefficient.

[0068] Specifically, the multi-parameter real-time calculation module 106 processes the parameters transmitted by the parameter real-time measurement module 104 and the optimal current distribution coefficient calculation module 105, and according to the optimal current distribution coefficient obtained by the optimal current distribution coefficient calculation module 105, and then according to the formula Calculate the phase shift angle of the control signal, and then transmit the obtained phase shift angle of the control signal to the real-time control module 107 of the transmitter power converter for control by the real-time control module 107 of the transmitter power converter. Multiple parameters

[0069] The multi-parameter real-time calculation module 106 also processes the mutual inductance between the transmitting coils measured by the parameter real-time measurement module 104 and the optimal current distribution coefficient obtained by the optimal current distribution coefficient calculation module 105, and calculates the equivalent self-inductance of each transmitting coil under optimal conditions. The internal calculation formula is:

[0070]

[0071] The multi-parameter real-time calculation module 106 respectively transmits the results obtained from the above two functions to the real-time control module 107 of the transmitter power converter and the regulation and judgment module 110 for further processing by these two modules.

[0072] The real-time control module 107 of the transmitter power converter will adjust the control program of each transmitter power converter in real time according to the phase shift angle of the control signal obtained by the multi-parameter real-time calculation module 106, so that the transmitter power converter can output a voltage that satisfies the optimal current distribution coefficient, and then obtain the transmitting coil current that satisfies the optimal current distribution coefficient.

[0073] In some embodiments, the multi-converter control module further includes:

[0074] A voltage stress detection and analysis module, connected to the transmitting coil, for detecting the voltage stress of the transmitting coil;

[0075] A transmitting coil spacing self-adjustment module, connected to the voltage stress detection and analysis module, for adjusting the spacing between the transmitting coils in response to the voltage stress being greater than or equal to a voltage stress threshold, and generating a coil spacing change signal to be sent to the parameter real-time measurement module to re-detect the inductance parameters of the transmitting coil.

[0076] Specifically, the main function of the voltage stress detection and analysis module 108 is to detect the voltage stress at both ends of the wireless power transfer coils 103-1, wireless power transfer coils 103-2... wireless power transfer coils 103-n in real time, and ensure that the voltage stress at both ends of the transmitting coil is within a safe range. The implementation method is to set a known voltage stress threshold in this module. If the maximum value of the voltage stress at both ends of each measured transmitting coil is less than this threshold, no signal is transmitted to the transmitting coil spacing self-adjustment module 109, and at the same time, a signal is sent to the regulation and judgment module 110. If the maximum value of the voltage stress at both ends of each measured transmitting coil is greater than this threshold, a signal is transmitted to the transmitting coil spacing self-adjustment module 109, and no signal is sent to the regulation and judgment module 110. This module is mainly to ensure that no safety problems such as internal breakdown of the coil occur during the large-energy transfer process of the transmitting coil.

[0077] When the transmitting coil spacing self-adjustment module 109 receives the signal from the voltage stress detection and analysis module 108, it indicates that the voltage stress at both ends of the transmitting coil exceeds the set threshold. Therefore, this module acts to adjust the spacing of the transmitting coils, mainly to increase the spacing of the transmitting coils. In addition, an action signal is sent to the parameter real-time measurement module 104 to make it re-measure the mutual inductance value between each transmitting coil and the mutual inductance value between the transmitting coil and the receiving coil, and re-run the foregoing processes of each part.

[0078] In some embodiments, the multi-parameter real-time calculation module is further configured to calculate an equivalent self-inductance parameter of the transmitting coil based on the inductance parameter and the optimal current distribution coefficient;

[0079] The multi-converter control module further includes:

[0080] A regulation and judgment module, connected to the voltage stress detection and analysis module, configured to send the equivalent self-inductance parameter of the parameter calculation module to the series variable capacitor real-time control module in response to the voltage stress being less than the voltage stress threshold;

[0081] A series variable capacitor real-time control module, connected to the regulation and judgment module, configured to adjust the series variable capacitor of the transmitting side compensation network based on the equivalent self-inductance parameter to make the transmitting side compensation network in a resonant condition.

[0082] Specifically, the regulation judgment module 110 is mainly used to reduce the number of actions of the series variable capacitor real-time control module 111, thereby reducing the number of actions of the variable capacitor, that is, reducing the life loss of the variable capacitor. When the regulation module 110 does not receive the action signal sent by the voltage stress detection and analysis module 108, it indicates that the voltage stress at both ends of the transmitting coil does not meet the set threshold requirements, and it is necessary to adjust the distance between the transmitting coils. When the distance between the transmitting coils changes, the equivalent self-inductance of each transmitting coil will also change. Without the blocking effect of the regulation module 110, the variable capacitor will be continuously adjusted, affecting the system operation performance. Only when the voltage stress of each transmitting coil meets the set requirements, the regulation judgment module 110 will receive the action signal and transmit the equivalent self-inductance parameters of each transmitting coil calculated in the multi-parameter real-time calculation module 106 to the series variable capacitor real-time control module 111 for further processing.

[0083] After receiving the signal from the regulation judgment module 110, the series variable capacitor real-time control module 111 regulates the series variable capacitors in each compensation network according to the equivalent self-inductance of each transmitting coil obtained by the multi-parameter real-time calculation module 106, so that the compensation network is in the resonance condition, and then makes the proposed wireless power transmission system work under the optimal conditions.

[0084] In some embodiments, the multi-converter control module further includes:

[0085] A variable capacitor value real-time measurement module, connected to the series variable capacitor of the transmitting side compensation network and the series variable capacitor real-time control module, for sending the detected capacitance value of the series variable capacitor to the series variable capacitor real-time control module;

[0086] The series variable capacitor real-time control module adjusts the series variable capacitor based on the equivalent self-inductance parameter to make the capacitance value of the series variable capacitor consistent with the target capacitance value corresponding to the equivalent self-inductance parameter.

[0087] Specifically, the variable capacitor value real-time detection module 112 compares the actually measured variable capacitor value with the variable capacitor value regulated by the series variable capacitor real-time control module 111 to ensure that the measured value is as close as possible to the calculated value and ensure that the compensation network is in the resonance condition. The main reason for adding this module is that the calculation accuracy requirements for the resonance parameters in the compensation network are relatively high.

[0088] In summary, through the collaborative work of the above-mentioned real-time parameter measurement module 104, optimal current distribution coefficient calculation module 105, multi-parameter real-time calculation module 106, transmitting-end power converter real-time control module 107, voltage stress detection and analysis module 108, transmitting coil spacing self-adjustment module 109, regulation judgment module 110, series variable capacitor real-time control module 111, and variable capacitor value real-time detection module 112, the maximum wireless power transmission efficiency under different conditions is achieved.

[0089] It can be seen that for the wireless power transmission device based on coaxial multi-transmitting coils according to the embodiments of the present disclosure, the multi-transmitting coil structure is adopted, increasing the wireless power transmission distance; the currents of each transmitting coil are distributed according to the designed optimal current distribution coefficient, increasing the transmission efficiency of the wireless power transmission system; when the distance between the load and the transmitting module or the size of the load changes, the system can adjust the optimal current distribution strategy in real time to ensure that the system is always in the optimal transmission efficiency; the compensation network at the transmitting end adopts a series variable capacitor, and when the current distribution coefficient of the transmitting coil changes, the capacitor can change in real time according to the equivalent self-inductance of the changing transmitting coil to ensure that the system operates under resonance conditions and ensure the transmission efficiency of the system.

[0090] Those of ordinary skill in the art should understand that: The discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples; under the concept of the present disclosure, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present disclosure as described above, which are not provided in detail for the sake of brevity.

[0091] In addition, for simplicity of explanation and discussion, and in order not to make the embodiments of the present disclosure difficult to understand, the well-known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided drawings. Furthermore, the device may be shown in block diagram form to avoid making the embodiments of the present disclosure difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present disclosure are to be implemented (i.e., these details should be fully within the understanding of those skilled in the art). In the case where specific details (such as circuits) are set forth to describe the exemplary embodiments of the present disclosure, it will be apparent to those skilled in the art that the embodiments of the present disclosure can be implemented without these specific details or with variations of these specific details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0092] Although the present disclosure has been described in connection with specific embodiments thereof, many alternatives, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art in light of the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0093] Embodiments of the present disclosure are intended to cover all such alternatives, modifications, and variations that fall within the broad scope of the appended claims. Accordingly, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. A wireless power transmission device based on coaxial multi-transmitting coils, characterized in that Comprising: A plurality of transmitting modules, each of the transmitting modules includes a transmitting coil, a transmitting-side compensation network, and a transmitting-side converter connected in sequence; A multi-converter control module, connected to the transmitting-side converter, for generating a control signal for the transmitting-side converter based on the inductance parameter of the transmitting coil to control the output voltage of the transmitting-side converter; the output voltage is compensated by the transmitting-side compensation network and then provided to the transmitting coil so that the transmitting coil operates under the condition of maximum wireless power transfer efficiency.

2. The device according to claim 1, characterized in that, The multi-converter control module includes: A parameter real-time measurement module, connected to the transmitting coil, for detecting the inductance parameter of the transmitting coil; A parameter calculation module, connected to the parameter real-time measurement module, for determining the phase shift angle of the control signal based on the inductance parameter; A converter real-time control module, connected to the parameter calculation module, for generating the control signal based on the phase shift angle to control the output voltage of the transmitting-side converter.

3. The device according to claim 2, characterized in that, The parameter calculation module includes: An optimal current distribution coefficient calculation module, connected to the inductance parameter module, for calculating the current distribution coefficient of the transmitting coil corresponding to the maximum wireless power transfer efficiency based on the inductance parameter; A multi-parameter real-time calculation module, connected to the optimal current distribution coefficient calculation module, for calculating the phase shift angle based on the current distribution coefficient.

4. The device according to claim 2, characterized in that, The multi-converter control module further includes: A voltage stress detection and analysis module, connected to the transmitting coil, for detecting the voltage stress of the transmitting coil; A transmitting coil spacing self-adjustment module, connected to the voltage stress detection and analysis module, for adjusting the spacing between the transmitting coils in response to the voltage stress being greater than or equal to a voltage stress threshold, and generating a coil spacing change signal to be sent to the parameter real-time measurement module to re-detect the inductance parameter of the transmitting coil.

5. The device according to claim 3, characterized in that, The multi-parameter real-time calculation module is further used to calculate the equivalent self-inductance parameter of the transmitting coil based on the inductance parameter and the optimal current distribution coefficient; The multi-converter control module further includes: A regulation judgment module, connected to the voltage stress detection and analysis module, for sending the equivalent self-inductance parameter of the parameter calculation module to the series variable capacitor real-time control module in response to the voltage stress being less than the voltage stress threshold; A series variable capacitor real-time control module, connected to the regulation judgment module, for adjusting the series variable capacitor of the transmitting-side compensation network based on the equivalent self-inductance parameter so that the transmitting-side compensation network is in a resonant condition.

6. The device according to claim 5, characterized in that, The multi-converter control module further includes: A variable capacitor value real-time measurement module, connected to the series variable capacitor of the transmitting-side compensation network and the series variable capacitor real-time control module, for sending the detected capacitance value of the series variable capacitor to the series variable capacitor real-time control module; The series variable capacitor real-time control module adjusts the series variable capacitor based on the equivalent self-inductance parameter so that the capacitance value of the series variable capacitor is consistent with the target capacitance value corresponding to the equivalent self-inductance parameter.

7. The device according to claim 3, characterized in that, The optimal current distribution coefficient calculation module calculates the current distribution coefficient of the transmitting coil corresponding to the maximum wireless power transfer efficiency based on the inductance parameters, and includes: Calculating the first-order partial derivative of the wireless power transfer efficiency formula: Solve for α at the maximum point i , while retaining the α i values that satisfy the following conditions: Substitute the obtained α i into the Hessian matrix. If the negative definite condition is satisfied, it is the optimal current distribution coefficient: where α i is the optimal current distribution coefficient of the i-th transmitting coil, η is the maximum wireless power transfer efficiency, and n is the number of transmitting coils.

8. The device according to claim 5, characterized in that, The equivalent self-inductance parameters include: Among them, L eqi_t is the equivalent self-inductance parameter, L i_t is the inductance value of the i-th transmitting coil, M ij is the mutual inductance value between the i-th transmitting coil and the j-th transmitting coil, α i is the optimal current distribution coefficient of the i-th transmitting coil, α j is the optimal current distribution coefficient of the j-th transmitting coil.

9. A wireless power transmission system based on coaxial multi-transmitting coils, characterized in that, Including: A wireless power transmitting device based on coaxial multi-transmitting coils according to any one of claims 1-8; And a wireless power receiving device, configured to receive the electric energy transmitted from the wireless power transmitting device and supply it to a load.

10. The system according to claim 9, characterized in that, The wireless power receiving device includes: A receiving coil, configured to receive the electric energy; A receiving-side compensation network, connected to the receiving coil, configured to compensate the electric energy to offset the noise and loss during the transmission process; A receiving-side converter, connected to the receiving-side compensation network, configured to convert the electric energy and supply it to the load.

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