Directional wireless power transmission system and method

Abstract

The invention discloses a directional wireless power transmission system and method, and belongs to the technical field of wireless power transmission, the system comprises a transmitting device and variable devices, the transmitting device can have two natural resonant frequencies, and the variable devices are arranged on the two sides of the transmitting device. Each variable device comprises a capacitor and an inductor which form the natural resonant frequency and are controlled by a capacitor switch to be switched on and switched off, and a load controlled by a load switch to be switched on and switched off, and coupling coefficients between a transmitting coil of the transmitting device and receiving coils of the variable devices and between the receiving coils of the variable devices are specially set; the variable device can be changed into a receiving device Rx or a relay device Ix through a capacitance switch and a load switch. The transmitting device and the variable device can form a one-dimensional dimer chain of a PT symmetrical structure and a Harper chain structure, energy can be directionally transmitted to a plurality of loads in one direction, and compared with the prior art, the robustness and transmission efficiency of electric energy transmission are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless power transmission, and more particularly to a directional wireless power transmission system and method. Background Art

[0002] In recent decades, wireless power transfer (WPT) technology has rapidly and extensively developed due to its high reliability, convenience, and safety. However, most WPT solutions are inherently sensitive to transmission distance and structural disturbances, making them difficult to adapt to diverse application scenarios. In the face of system parameter perturbations, such as changes in coil coupling and component parameter drift, energy transmission stability deteriorates, leading to a sharp drop in efficiency and even power failure. Furthermore, in the face of internal structural disturbances, such as minor layout deviations and environmental interference, transmission performance fluctuates significantly, resulting in insufficient robustness.

[0003] In addition, most existing WPT systems use omnidirectional transmission, and electrical energy is dispersed into the surrounding space. Energy will also be wasted in areas outside the target receiving device, and it is easy to cause electromagnetic interference to surrounding electronic equipment, causing transmission efficiency to further decrease.

[0004] Moreover, existing WPT systems require complex active tuning to adjust transmission distances or switch loads, such as manually changing circuit parameters and frequently switching frequencies. These operations are cumbersome and prone to loss of efficiency. They are unable to automatically maintain optimal power transmission over a wide range of distances, significantly reducing their efficiency in practical applications.

[0005] In addition, the existing WPT system basically has no active capabilities. The transmitter cannot accurately obtain the status of each load and can only blindly broadcast energy, which can easily lead to overcharging and overcurrent of some loads, and cannot give priority to urgently needed charging equipment, and lacks intelligent and refined management. Summary of the Invention

[0006] In view of the problems of insufficient robustness and low transmission efficiency of existing wireless power transmission systems, the present invention proposes a directional wireless power transmission system and method.

[0007] In one aspect of the present invention, a directional wireless power transmission system is proposed for charging a load, comprising a transmitting device and a variable device, wherein the transmitting device comprises: a main capacitor C1; a transmitting coil, whose inductance L1 is connected in series with the main capacitor C1 to form a natural resonant frequency of a first frequency f 1 resonant network; an inverter circuit connected to the main capacitor C1, for converting the input DC power into a frequency matching the first frequency f1 AC power, and drives the resonant network to cause the transmitting coil to transmit wireless AC power; the main capacitor switch is used to control the connection and disconnection of the main capacitor C1 and the inverter circuit; the variable device includes variable devices 1~n..., n is a natural number greater than 1, and the variable devices 1~n are sequentially arranged on the first side of the transmitting device, each variable device includes: auxiliary capacitor C 1p and auxiliary capacitor C 1s , where C 1S +C 1P =C1; auxiliary capacitor switch, used to control the auxiliary capacitor C 1p and auxiliary capacitor C 1s The connection and disconnection of the receiving coil, its inductance L2 and the auxiliary capacitor C 1p and auxiliary capacitor C 1s The natural resonant frequency of the series structure is also the first frequency f 1, wherein the inductance values ​​of the inductor L1 and the inductor L2 are equal; a rectifier circuit is electrically connected to the receiving coil and is used to convert the wireless AC power received by the receiving coil into DC power; a load switch is used to control the connection and disconnection of the load and the rectifier circuit; on the first side, the coupling coefficient between the transmitting coil and the receiving coil of the variable device 1 is k1, the coupling coefficient between the receiving coils of the variable device 1 and the variable device 2 is k2, the coupling coefficient between the receiving coils of the variable device 2 and the variable device 3 is k1, the coupling coefficient between the receiving coils of the variable device 3 and the variable device 4 is k2, and so on, wherein k1 < k2; when the main capacitor switch of the transmitting device is closed, the directional wireless power transmission system transmits power at a first frequency f 1 as the operating frequency. When the auxiliary capacitance switch and the load switch of the variable device are closed at the same time, the variable device becomes the receiving device Rx. When the auxiliary capacitance switch of the variable device is closed and the load switch is opened, the variable device becomes the relay device Ix.

[0008] In the above aspect of the present invention, it is preferred that the auxiliary capacitor C 1p and the auxiliary capacitor C 1s The capacitance values ​​are equal.

[0009] In the above aspects of the present invention, in a further implementation scheme, the transmitting device also includes a main control unit and a main communication unit, and the main control unit is used to control the switching state of the main capacitor switch; the variable device also includes an auxiliary control unit, an auxiliary communication unit and a data acquisition unit, the main communication unit and the auxiliary communication unit are communicatively connected, the data acquisition unit is used to collect the current and voltage of the load, and the auxiliary control unit is used to control the switching state of the auxiliary capacitor switch and the load switch based on the current and voltage of the load collected by the data acquisition unit.

[0010] In the above aspect of the present invention, in a further embodiment, the primary communication unit and the secondary communication unit are connected via a wireless method; the wireless method includes Bluetooth, WiFi and Zigbee.

[0011] In the above aspects of the present invention, in a further embodiment, the variable device also includes: a DC-DC converter, the DC-DC converter includes a switching tube controlled by a PWM signal, and the input end of the DC-DC converter is connected to the output end of the rectifier circuit, and the output end of the DC-DC converter is connected to the load; a PI closed-loop control module, the PI closed-loop control module is electrically connected to the data acquisition unit and the auxiliary control unit, the input of the PI closed-loop control module is the current and voltage of the load collected by the data acquisition unit and the expected voltage value and the expected current value provided by the auxiliary control unit; a PWM generator, the PWM generator is controlled by the output of the PI closed-loop control module to provide the desired PWM signal to the DC-DC converter, wherein the main control unit is further configured to calculate the equivalent resistance Req based on the voltage and current of the load, and control the PWM signal through the PI closed-loop control module according to the equivalent resistance Req, so that the DC-DC converter can provide constant current CC charging or constant voltage CV charging for the load.

[0012] In the above aspects of the present invention, in a further embodiment, when the equivalent resistance Req is within the range of 0 to the first resistance preset value X1, the main control unit determines the control target of the PI closed-loop control module as current, and controls the PWM signal through the PI closed-loop control module, so that the DC-DC converter provides constant current CC charging for the load; when the equivalent resistance Req is within the range of the first resistance preset value X1 to the second resistance preset value X2, the main control unit determines the control target of the PI closed-loop control module as voltage, and controls the PWM signal through the PI closed-loop control module, so that the DC-DC converter provides constant voltage CV charging for the load.

[0013] In the above aspects of the present invention, in a further embodiment, a second directional wireless power transmission system is proposed as an improvement of the first directional wireless power transmission system, wherein the transmitting device further includes: a capacitor C2 connected to the inverter circuit; the main capacitor switch includes a first main capacitor switch and a second main capacitor switch, the first main capacitor switch is used to control the connection and disconnection of the capacitor C1 and the inverter circuit, and the second main capacitor switch is used to control the connection and disconnection of the capacitor C2 and the inverter circuit, wherein the transmitting coil and the capacitor C2 are connected in series to form a natural resonant frequency of the second frequency f 2 resonant network; the inverter circuit is used to convert the input DC power into a frequency matching the first frequency f 1 or second frequency f2, and drives the resonant network to cause the transmitting coil to transmit wireless energy; the variable device also includes variable devices n+1~2n, which are sequentially arranged on the second side of the transmitting coil opposite to the first side, and each variable device also includes: an auxiliary capacitor C 2p and auxiliary capacitor C 2s , where C 2S +C 2P = C2, where the receiving coil and the capacitor C 2p and capacitor C 2s The natural resonant frequency of the series structure is also the second frequency f 2 resonant network; the auxiliary capacitor switch includes a first auxiliary capacitor switch and a second auxiliary capacitor switch, the first auxiliary capacitor switch is used to control the auxiliary capacitor C 1p and auxiliary capacitor C 1s The second auxiliary capacitor switch is used to control the connection and disconnection of the auxiliary capacitor C 2p and auxiliary capacitor C 2s On the second side, the coupling coefficient between the coils is distributed as on the first side; in the case of closing the first main capacitive switch of the transmitting device, the directional wireless power transmission system is at a first frequency f 1 as the operating frequency, when the first auxiliary capacitor switch and the load switch of the variable device 1~n are closed at the same time, the variable device 1~n becomes the receiving device Rx, when the first auxiliary capacitor switch of the variable device 1~n is closed and the load switch is opened, the variable device 1~n becomes the relay device Ix; when the second main capacitor switch of the transmitting device is closed, the directional wireless power transmission system operates at the second frequency f 2 as the operating frequency. When the second auxiliary capacitor switches and load switches of the variable devices n+1 to 2n are closed at the same time, the variable devices n+1 to 2n become receiving devices Rx. When the second auxiliary capacitor switches of the variable devices n+1 to 2n are closed and the load switches are opened, the variable devices n+1 to 2n become relay devices Ix.

[0014] In a second aspect of the present invention, a directional wireless power transmission method is proposed. The directional wireless power transmission method is implemented by a first directional wireless power transmission system according to the first aspect of the present invention, comprising the following steps: disconnecting the main capacitor switch, the auxiliary capacitor switch, and the load switch, placing the directional wireless power transmission system in a standby mode so that all coils are in a decoupled state, and collecting the voltage and current of the load at this time; determining the load with the minimum voltage as the target load based on the collected load voltage; and determining the current of the target load at the target load. IWhen 0 is zero, the auxiliary capacitance switch and the load switch of the target variable device where the target load is located are closed at the same time, so that the target variable device becomes the receiving device Rx, and the auxiliary capacitance switches of all intermediate variable devices between the transmitting device and the target variable device are closed, so that all the intermediate variable devices become relay devices Ix; when the voltage of the target load reaches a predetermined proportion of its rated voltage, the auxiliary capacitance switch and the load switch of the target variable device are disconnected at the same time; the load with the second smallest voltage is determined as the target load, and the above steps are repeated until the voltages of all loads reach a predetermined proportion of their rated voltages.

[0015] In the above aspects of the present invention, in a further embodiment, a first resistance preset value X1 and a second resistance preset value X2 are set, wherein X1<X2; the equivalent resistance Req of the load is calculated based on the collected voltage and current of the load; when Req is in the range of 0 to X1, the current input to the load is controlled to provide constant current CC charging to the load; when Req is in the range of X1 to X2, the voltage input to the load is controlled to provide constant voltage CV charging to the load.

[0016] In a third aspect of the present invention, a directional wireless power transmission method is proposed, which is implemented by the second directional wireless power transmission system according to the first aspect of the present invention, comprising the following steps: disconnecting the first main capacitor switch, the second main capacitor switch, the first auxiliary capacitor switch, the second auxiliary capacitor switch and the load switch, placing the directional wireless power transmission system in a standby mode, so that all coils are in a decoupled state, collecting the voltage and current of the load; determining the load with the minimum voltage as the target load based on the collected load voltage; and determining the target load current at the target load. I When 0 is zero, the first main capacitor switch or the second main capacitor switch is closed accordingly according to whether the target load is on the first side or the second side to determine the operating frequency of the directional wireless power transmission system; at the same time, the auxiliary capacitor switch and the load switch of the target variable device where the target load is located are closed, so that the target variable device becomes the receiving device Rx, and the auxiliary capacitor switches of all intermediate variable devices between the transmitting device and the target variable device are closed, so that all the intermediate variable devices become relay devices Ix; when the voltage of the target load reaches a predetermined proportion of its rated voltage, the auxiliary capacitor switch and the load switch of the target variable device are disconnected at the same time; the load with the second smallest voltage is determined as the target load, and the above steps are repeated until the voltages of all loads reach a predetermined proportion of their rated voltages.

[0017] The beneficial effects of the present invention are: The directional wireless power transmission system of the present invention comprises a transmitter and multiple variable devices, constructing a one-dimensional dimer chain with both PT symmetry and Harper chain structures. Due to the topological dimer chain characteristics of the Harper structure, it can maintain robust energy transmission against perturbations of system parameters even in longer chain structures. Furthermore, as the number of chain structures, i.e., the number of coils, increases, the localization of the topological state gradually increases. This localization of the topological state concentrates energy along specific paths, reducing energy scattering caused by fluctuations in chain parameters. Energy is more likely to be transmitted from the transmitter along a specific direction (such as a topologically protected boundary state path) rather than diffuse in other directions. This system is particularly suitable for scenarios requiring "point-to-point" directional transmission. Therefore, the present invention effectively addresses the current problems of insufficient robustness and low transmission efficiency in WPT systems.

[0018] The one-dimensional dimer chain of the PT symmetric structure and Harper chain structure constructed by the present invention allows each variable device in one direction of the chain to become a receiving device, while the variable device between the transmitting and receiving devices in that direction can also become a relay device, thereby transmitting energy directionally to multiple loads in one direction. This allows the Harper structure system to support n loads with low losses. This feature can expand the number of loads to 2n in a bipolar arrangement mode, specifically supporting the charging of more than 6 loads.

[0019] The transmitting device and the variable device of the directional wireless power transmission system of the present invention can communicate with each other, wherein the transmitting device is configured with a main communication unit and a main control unit, and the variable device is configured with a data acquisition unit, an auxiliary communication unit and an auxiliary control unit. The main control unit can obtain and control the state of the variable device through the main and auxiliary communication units, so that the load to be charged and the charging of the load can be selected according to the state of the load of the variable device. Compared with the existing wireless power transmission system that cannot select the load and cannot control the charging termination of the load, the present invention has the initiative to charge the load, can actively select the load that urgently needs to be charged, and can actively disconnect the charging of the load that has reached a predetermined state, thereby avoiding overcharging and overcurrent of the load.

[0020] The variable device of the directional wireless power transmission system of the present invention adopts a PI closed-loop control module and a DC-DC converter. The main control unit can use the PI closed-loop control module to adjust the output of the DC-DC converter by comparing the equivalent resistance of the load, so that when the load is in a "low-resistance state", a constant-current CC charging mode is adopted, and when the load is in a "medium-resistance state", a constant-voltage charging mode is adopted, thereby not only improving the charging efficiency of the load, but also extending the load life. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which form a part of the present invention, are used to provide a further understanding of the present invention, making other features, objectives, and advantages of the present invention more apparent. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0022] In addition, throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the elements and components are not necessarily drawn to scale.

[0023] In the drawings: Figure 1 is a demonstration diagram of how to form boundary states, where the coupling strength k1 < k2 between the coils is such that the one-dimensional dimer chain of the system forms a Harper chain.

[0024] Figure 2 is an energy band diagram obtained according to the coupling strength in the topological Harper chain under the finite tight-binding model, where energy is strongly localized at both ends of the chain at different frequencies in the band gap of the energy band.

[0025] Figure 3 is a circuit topology diagram of the directional wireless power transmission system of the present invention.

[0026] Figure 4 is a structural block diagram of the transmitting device and the receiving device of the directional wireless power transmission system of the present invention.

[0027] Figure 5 is a structural block diagram of the PI closed-loop control module of the variable device of the present invention.

[0028] Figure 6 is a flowchart of an embodiment of the directional wireless power transmission method of the present invention.

[0029] Figure 7 is a flowchart of another embodiment of the directional wireless power transmission method of the present invention. Detailed Embodiments

[0030] The embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not used to limit the protection scope of the present disclosure.

[0031] The booming development of artificial microstructures has sparked a surge in research in topological photonics. These optical topological structures have not only revealed some intriguing topological phases and topological edge states in experiments but also provided powerful means for manipulating electromagnetic waves. One-dimensional topological chains, in particular, have opened up new avenues for the development of topological photonics. Despite their simple structure, one-dimensional topological chains possess a rich set of topological properties, such as topological phase transitions, band inversions, and robust topological edge states. The robustness of one-dimensional topological chains stems from the topologically protected edge states within their topological structures. This robustness differs from oscillatory circuits, metamaterials, and third-order PT symmetric systems that utilize nonlinear saturation gain to achieve automatic tracking of purely real eigenfrequencies. For example, in a one-dimensional dimer chain, a pair of edge states are symmetrically distributed at either end of the chain. Unlike the symmetrical distribution of edge states in a topological dimer chain, the topological edge states in a quasi-periodic Harper chain are located at either the left or right end of the chain, enabling the realization of directional WPT.

[0032] The present invention aims to achieve multi-load directional energy transfer and enhance the robustness of transmission. When the topological dimer chain is long enough, the edge state can be localized at the chain boundary, and the wave function decays exponentially with the distance from the boundary. As the chain grows, the localization of the topological state will gradually increase, and the exponential decay characteristics will also gradually increase, forming an edge state with ideal local properties. Figure 2 , energy is strongly localized at the ends of the chain at different frequencies within the band gap. This means that compared to many current near-field wireless power transmission systems, which suffer from a reduction in robustness due to distance, the directional wireless power transmission system of the present invention has a longer transmission distance and is more stable.

[0033] According to one embodiment of the present invention, a directional wireless power transmission system for charging a load is proposed, the directional wireless power transmission system comprising a transmitting device and a variable device, wherein the transmitting device comprises: a main capacitor C1; a transmitting coil, whose inductance L1 is connected in series with the main capacitor C1 to form a natural resonant frequency of a first frequency f 1 resonant network; an inverter circuit connected to the main capacitor C1, for converting the input DC power into a frequency matching the first frequency f 1 AC power, and drives the resonant network to make the transmitting coil transmit wireless AC power; the main capacitor switch is used to control the connection and disconnection of the main capacitor C1 and the inverter circuit. The input of the inverter circuit is a DC power supply, and the output is a frequency matching the first frequency f 1 alternating current, thereby providing alternating current to the transmitting coil to generate an alternating magnetic field. The main capacitor C1 and the transmitting coil together form a resonant network, and its resonant frequency determines the operating frequency of the transmitting device.

[0034] See Figure 3The variable device includes variable devices 1 to n, where n is a natural number greater than 1, and the variable devices 1 to n are sequentially arranged on the first side of the transmitting device, and each variable device includes: an auxiliary capacitor C 1p and auxiliary capacitor C 1s , where C 1S +C 1P =C1; auxiliary capacitor switch, used to control the auxiliary capacitor C 1p and auxiliary capacitor C 1s The connection and disconnection of the receiving coil, its inductance L2 and the auxiliary capacitor C 1p and auxiliary capacitor C 1s The natural resonant frequency of the series structure is also the first frequency f 1, wherein the inductance values ​​of the inductor L1 and the inductor L2 are equal; a rectifier circuit, electrically connected to the receiving coil, for converting the wireless AC power received by the receiving coil into DC power; and a load switch, for controlling the connection and disconnection of the load and the rectifier circuit.

[0035] In the above embodiment, on the first side, the coupling coefficient between the transmitting coil and the receiving coil of the variable device 1 is k1, the coupling coefficient between the receiving coils of the variable device 1 and the variable device 2 is k2, the coupling coefficient between the receiving coils of the variable device 2 and the variable device 3 is k1, the coupling coefficient between the receiving coils of the variable device 3 and the variable device 4 is k2, and so on, where k1<k2, see Figure 1 At this time, the system constructs a one-dimensional dimer chain with both PT (Parity-Time) symmetric structure and Harper chain structure.

[0036] In the above embodiment, when the main capacitor switch of the transmitting device is closed, the directional wireless power transmission system transmits power at a first frequency. f 1 as the operating frequency. When the auxiliary capacitance switch and the load switch of the variable device are closed at the same time, the variable device becomes the receiving device Rx. When the auxiliary capacitance switch of the variable device is closed and the load switch is opened, the variable device becomes the relay device Ix.

[0037] According to this embodiment of the present invention, the inductance of the transmitting coil is connected in series with the main capacitor to form a natural resonant frequency of f 1 resonant network. The inverter circuit converts the input DC into a frequency matching the first frequency f 1 alternating current is injected into the network, causing the transmitting coil to operate at the first frequency f 1 resonance, radiating wireless AC power outward, the inductance of the receiving coil of the variable device and the auxiliary capacitor form a resonant frequency which is also the first frequency f1 resonant network. When both the auxiliary capacitor switch and the load switch are closed, the receiving coil resonates to receive AC power, which is then converted to DC by the rectifier circuit and supplied to the load. If the load switch is disconnected, the variable device functions as a relay, relaying the AC power using its resonant characteristics. The capacitor switch and load switch of the present invention can be relays.

[0038] It's worth noting that when variable devices 1 and n+1 act as receiving coils, the directional wireless power transmission system exhibits PT-symmetric wireless power transmission. However, when variable devices 2-n and n+2-2n act as receiving coils, the directional wireless power transmission system adopts a Harper structure. Due to the characteristics of the Harper structure, when the other coils are disconnected, the transmitting coil can transfer energy in a directionally controlled manner to any resonant coil.

[0039] See again Figure 3 Taking the directional wireless power transmission system of the present invention as an example to charge the loads R1, R2, and R3 located on the first side, when the system charges the load R1, the variable device containing R1 closes the capacitor switch and the load switch to become the receiving device R X , the capacitance switch and load switch in other variable devices are disconnected, and the transmitting device T X A wireless power transmission system with a PT symmetrical structure is formed with a receiving device including R1.

[0040] When the system charges the load R2, the variable device containing R2 closes the capacitor switch and the load switch becomes the receiving device R X At this time, the variable device containing R1 closes the capacitor switch and opens the load switch to become the relay device I X , the capacitor switches and load switches in other devices are disconnected, and the relay device containing R1 and the transmitting device T X A wireless power transmission system including a receiving device containing R2 forms a Harper chain structure.

[0041] When the system charges the load R3, the variable device containing R3 closes the capacitor switch and the load switch becomes the receiving device R X At this time, the variable device containing R1 and R2 closes the capacitor switch and opens the load switch to become the relay device I X , the capacitor switches and load switches in other devices are disconnected, and the relay device containing R1 and R2 is disconnected from the transmitting device T X And the receiving device containing R3 forms a wireless power transmission system with a Harper chain structure.

[0042] In a preferred embodiment of the present invention, the auxiliary capacitance C of each variable device 1p and auxiliary capacitor C 1sThe capacitance values ​​are equal. After testing, it is found that in this case the power transmission efficiency and power are relatively high.

[0043] See Figure 4 In one embodiment of the present invention, the transmitting device further includes a main control unit and a main communication unit, and the main control unit is used to control the switching state of the main capacitor switch; the variable device further includes an auxiliary control unit, an auxiliary communication unit and a data acquisition unit, the main communication unit and the auxiliary communication unit are communicatively connected, the data acquisition unit is used to collect the current and voltage of the load, and the auxiliary control unit is used to control the switching states of the auxiliary capacitor switch and the load switch based on the current and voltage of the load collected by the data acquisition unit.

[0044] As an example, the auxiliary control unit controls the switching state of the auxiliary capacitor switch and the load switch as follows: set fields a, b, and c, and the three fields represent the nth device, capacitor switch, and load switch, respectively. 1 indicates closing the capacitor switch or load switch, and 0 indicates opening the capacitor switch or load switch. When charging the load on the nth variable device, the main control unit sends an instruction to the auxiliary control unit: field a=n, field b=1, field c=1. At this time, a signal is sent to devices 1 to n-1 through a for loop logic algorithm, closing only the capacitor switch and opening the load switch: field a=device number i, field b=1, field c=0.

[0045] In one embodiment of the present invention, the primary communication unit and the secondary communication unit are connected wirelessly. Wireless connection offers numerous advantages over wired connections. It frees the system from the constraints of physical wiring, greatly enhancing the flexibility of system deployment and reducing wiring costs and space constraints. Furthermore, wireless connection effectively prevents communication failures caused by aging or damaged wiring, thereby improving system reliability and stability. Furthermore, wireless connection allows the system to more easily adapt to diverse application scenarios and environmental changes, providing strong support for the widespread application of directional wireless power transmission systems.

[0046] In one embodiment of the present invention, the wireless method includes Bluetooth, WiFi, and Zigbee. Bluetooth technology features low power consumption and stable short-range communication. It is suitable for transmitters and variable devices with high power requirements and short communication distances. It enables efficient communication between the main communication unit and one or a few short-range variable devices. WiFi technology offers high data transmission rates and a wide coverage range, ensuring fast data exchange between the main communication unit and multiple variable devices. Zigbee technology, with its low power consumption and low cost, enables collaborative operation and data sharing between transmitters and variable devices.

[0047] In one embodiment of the present invention, the variable device further includes a DC-DC converter, a PI closed-loop control module and a PWM generator, the DC-DC converter includes a switch tube controlled by a PWM signal, and the input end of the DC-DC converter is connected to the output end of the rectifier circuit, and the output end of the DC-DC converter is connected to the load; the PI closed-loop control module is electrically connected to the data acquisition unit and the auxiliary control unit, and the input of the PI closed-loop control module is the current and voltage of the load collected by the data acquisition unit and the expected voltage value and the expected current value provided by the auxiliary control unit; the PWM generator is controlled by the output of the PI closed-loop control module to provide a desired PWM signal to the DC-DC converter; the main control unit is further configured to calculate the equivalent resistance Req based on the voltage and current of the load, and control the PWM signal through the PI closed-loop control module according to the equivalent resistance Req, so that the DC-DC converter can provide constant current CC charging or constant voltage CV charging for the load.

[0048] In a specific embodiment, the PI closed-loop control module is controlled by the main control unit through the main-slave communication unit and the auxiliary control unit. Figure 5 , which is a simplified structural block diagram of the PI closed-loop control module of the variable device of the present invention. In the voltage branch, the actual output voltage is collected and converted into an effective value, and then substituted into the output voltage estimation formula to obtain a voltage feedback amount that is compatible with the control logic; in the current branch, the actual output current is collected and converted into an effective value, and then substituted into the output current estimation formula to obtain a current feedback amount that is compatible with the control logic. It is worth mentioning that by calculating the effective value, the noise, delay and error in the measurement can be better handled, and a more stable and reliable control signal can be provided. The effective value does not simply replace the actual value, but improves the accuracy, stability and response speed of the control module by compensating for the effects of measurement inaccuracies and fluctuations. Therefore, calculating the effective value can help the control module maintain higher robustness and adaptability when facing complex and dynamic environments.

[0049] The expected voltage value is compared with the voltage feedback value to obtain the voltage deviation; the expected current value is compared with the current feedback value to obtain the current deviation. The "selection judgment" module, executed by the main control unit, first selects whether the PI closed-loop control module's control target is current or voltage based on the load demand and current load status. In a system with multiple loads, the main control unit can dynamically adjust the target based on the remaining capacity or status of each load. For example, if a load is fully charged, the main control unit can reduce the current output or change the charging strategy. The input to the PI closed-loop control module is the voltage deviation or current deviation—the difference (error) between the current measured value and the target value. By calculating this error, the PI closed-loop control module generates an output signal. The output of the PI closed-loop control module typically consists of two components: a proportional term and an integral term. The proportional term adjusts the control output based on the current error multiplied by a proportional gain (Kp). The integral term integrates historical errors to prevent static error accumulation and is multiplied by an integral gain (Ki) to further adjust the output. Finally, the output of the PI closed-loop control module is used to adjust the duty cycle of the PWM (pulse-width modulation) signal, thereby adjusting the on / off time of the DC-DC converter's switches, precisely controlling the output voltage and current to match the load's requirements. Specifically, if the control target is current, adjusting the PWM signal maintains the current. If the control target is voltage, adjusting the PWM signal maintains the voltage.

[0050] The advantage of the present invention is that in the initial stage of charging, when the battery voltage is low, the battery is charged with a constant current. When the battery voltage reaches the constant voltage threshold, constant voltage charging is switched to. At this time, the charging current gradually decreases as the battery is saturated. Studies have shown that when the load is a lithium-ion battery, the energy efficiency can reach 85%-90% when the CC+CV mode is used for charging, while simple constant current charging may cause the efficiency to drop below 70% due to overcharging. In addition, the constant current is usually set within the safe range allowed by the battery to avoid large current causing lattice distortion of the electrode material, thereby reducing problems such as increased internal resistance and capacity attenuation of the battery; and the constant voltage threshold strictly matches the rated voltage of the battery to prevent excessive voltage from causing electrolyte decomposition and electrode passivation that cause battery life to decay. In summary, the CC+CV charging mode uses the strategy of "fast constant current filling first, precise saturation at constant voltage later", which not only takes advantage of the speed advantage of the constant current mode, but also avoids the risk of overcharging through the constant voltage mode, and balances the requirements of efficiency and life from the electrochemical nature.

[0051] The present invention discloses a directional wireless power transmission method, which is implemented by the above-mentioned directional wireless power transmission system. Figure 6The directional wireless power transmission method of the present invention comprises the following steps: disconnecting the main capacitor switch, the auxiliary capacitor switch and the load switch, placing the directional wireless power transmission system in a preparation mode, making all coils in a decoupled state, collecting the voltage and current of the load at this time; determining the load with the minimum voltage as the target load based on the collected load voltage; and determining the target load current at the target load current. I When 0 is zero, the auxiliary capacitor switch and the load switch of the target variable device where the target load is located are closed at the same time, so that the target variable device becomes the receiving device Rx, and the auxiliary capacitor switches of all intermediate variable devices between the transmitting device and the target variable device are closed, so that all the intermediate variable devices become relay devices Ix, thereby charging the target load; when the voltage of the target load reaches a predetermined ratio of its rated voltage, the auxiliary capacitor switch and the load switch of the target variable device are opened at the same time, and the predetermined ratio is, for example, 98%. That is, when the voltage of the target load reaches 98% of its rated voltage, charging can be stopped. Figure 6 The 98%Y in the formula represents 98% of the rated voltage of the target load); the load with the second smallest voltage is determined as the target load, and the above steps are repeated until the voltages of all loads reach a predetermined proportion of their rated voltages.

[0052] It's worth noting that when a battery is fully charged (or nearly fully charged) for an extended period, the structure of the electrode material gradually changes, reducing the amount of active material and leading to an irreversible decrease in battery capacity. Research has shown that charging to 98% of the battery's rated voltage can reduce the time the battery is exposed to high voltage, lowering the likelihood of these adverse reactions and thus extending the battery's service life. Furthermore, when a battery is overcharged, its internal temperature rises, potentially leading to safety issues such as thermal runaway. Especially in high-temperature environments, continuing to charge to full charge increases internal pressure, increasing the risk of bulging, fire, or even explosion. Stopping charging at 98% can, to a certain extent, reduce battery heat generation and mitigate safety hazards associated with excessive temperatures. The directional wireless power transmission method of the present invention provides proactive load charging. Specifically, it can select loads to be charged and terminate charging based on the load status of the variable device. It can proactively select loads that urgently need charging and proactively disconnect charging for loads that have reached a predetermined state, thereby preventing overcharging and overcurrent.

[0053] See again Figure 3 When the system charges R1, the capacitance switch and load switch on the variable device containing R1 are closed, and the capacitance switches and load switches on other variable devices are opened. At this time, the transmitting device and the receiving device containing R1 are in a PT symmetrical wireless power transmission structure.

[0054] PT symmetry requires the following conditions to be met: Analyze the two-order PT-WPT system, construct the second-order Hamiltonian equation, and obtain the formula of the equivalent system: (1) in represents the resonant angular frequency of the nth LC circuit, represents the intrinsic loss rate of the nth LC circuit, represents the intrinsic loss rate of the load, is the load resistance, g is the gain of the transmitting coil, , g A is the total gain of the system, , U in is the system input voltage, a is the modulus value, is the coupling coefficient between two adjacent coils. Keep the same resonant angular frequency between the coils .

[0055] By solving the characteristic equation, we can get: (2) make , we can get the real and imaginary parts of the equation: (3) From formula (3), we can further solve hour: (4) It can be seen from formula (4) that when the gain is equal to the loss, the resonant frequency of the system has a wide coupling characteristic, that is, the system has a robust transmission advantage at this time. Figure 3 If any receiving device in the system is equivalent to a simple series topology of inductors and capacitors, the following formula can be obtained, where the load is represented by R L : (5) Break it down into , the equivalent capacitance and resistance can be obtained as: (6) (7) (8) (9) From formula (9), we can see that Than the original load To be smaller, so its intrinsic loss rate To decrease, as can be seen from the one-dimensional dimer chain, when the intrinsic loss rate of the load is smaller, the robustness of the system will be enhanced.

[0056] When the system charges R2, at this time, the variable device containing R1 closes the capacitive switch and disconnects the load switch, and its C 1P +C 1S = C1, making it meet the resonance requirements and have the same natural resonance frequency, so that it changes from a receiving device to a relay device. The capacitive switch and load switch of the variable device containing R2 close to become a receiving device. At this time, because the coupling coefficients between the devices are k1 and k2, and k1 < k2, it meets the conditions of the Harper chain.

[0057] When the system charges R3, at this time, the variable device containing R2 and R1 closes the capacitive switch and disconnects the load switch, and its C 1P +C 1S = C1, making it meet the resonance requirements and have the same natural resonance frequency, so that it changes from a receiving device to a relay device. The capacitive switch and load switch of the variable device containing R3 close to become a receiving device. At this time, because the coupling coefficients between the devices are k1, k2, and k1, and k1 < k2, it meets the conditions of the Harper chain.

[0058] That is to say, when the operating frequency of the system is in f 1, the transmitted energy of the wireless power transfer system in the form of the Harper chain is strongly localized on the first side of the chain.

[0059] Next, a formula derivation is carried out for the wireless power transfer system in the form of the Harper chain. After determining the stable TEM (Transverse Electromagnetic Mode) in the topological dimer chain, further observing the effective transmission of TEM based on the standard multi-coil WPT system, the dynamics of the multi-coil system ignoring the intrinsic loss can be described by the coupled-mode equation as: (10) Where represents the incident wave, is the mode amplitude. The explanations of other parameters are the same as above.

[0060] The above is the coupled-mode equation of the Harper chain. However, when studying the Harper chain with the Hamiltonian in topological physics, the power transfer efficiency (transmittance) of the one-dimensional dimer chain can be expressed as , where the transmission coefficient can be determined by the transmitted wave , where considering the zero reflected wave , the Hamiltonian of the second-order open system realized by the Harper chain can be expressed as (11) where represents the coupling coefficient between the transmitting coil and the variable device that is charging the load. When the system Hamiltonian satisfies , so it also satisfies the wide coupling condition.

[0061] Referring to Figure 7 , in an embodiment of the present invention, a first resistance preset value X1 and a second resistance preset value X2 are set in the above-mentioned directional wireless power transmission method, where X1 < X2; the main control unit of the transmitting device calculates the equivalent resistance Req of the load according to the voltage and current of the load collected by the data acquisition unit; when Req is within the range of 0 to X1, the PI closed-loop control module controls the current input to the load to provide constant current CC charging for the load; when Req is within the range of X1 to X2, the PI closed-loop control module controls the voltage input to the load to provide constant voltage CV charging for the load. When the equivalent internal resistance Req ≥ X2, it can be considered that the load is fully charged.

[0062] Specifically, the data acquisition unit monitors the load terminal voltage U and current I in real time, and calculates Req = U / I through Ohm's law. When the load equivalent resistance Req < X1, the load is in a "low resistance state" (similar to a small internal resistance when the battery power is low), and at this time, constant current charging is suitable; when Req ≥ X1, the load enters a "medium resistance state" (the internal resistance increases after the power increases), and switches to the constant voltage mode; when Req ≥ X2, the load internal resistance increases significantly (the battery internal resistance can increase to 2-3 times the initial value when approaching full charge), and it is determined as the "full charge state", and charging stops.

[0063] Taking a 5V / 2A wireless charging system as an example, X1 is usually set to 2.5Ω - 3Ω. When the CC current is 2A and the load voltage is 5V, Req = 2.5Ω at this time; X2 is set to 10Ω - 15Ω. When the CV voltage is 5V and the cut-off current is 0.3A - 0.5A, Req = 10Ω - 16.7Ω. By dividing the CC / CV stage through the resistance threshold, the battery power state is converted into a resistance signal, and intelligent management of wireless charging is achieved by combining the PI closed-loop control. Different types of batteries (lithium batteries / lead-acid batteries) and load devices are adapted through the resistance threshold, and the coupling fluctuations in wireless transmission are offset through closed-loop control to avoid overcharging and overcurrent.

[0064] Return to refer to Figure 3The present invention further discloses a second directional wireless power transmission system, which is a further improvement of the first directional wireless power transmission system. In this second directional wireless power transmission system, the transmitting device further includes: a capacitor C2 connected to the inverter circuit; a main capacitor switch including a first main capacitor switch and a second main capacitor switch, the first main capacitor switch being used to control the connection and disconnection of the capacitor C1 and the inverter circuit, and the second main capacitor switch being used to control the connection and disconnection of the capacitor C2 and the inverter circuit, wherein the transmitting coil and the capacitor C2 are connected in series to form a natural resonant frequency of the second frequency. f 2 resonant network; the inverter circuit is used to convert the input DC power into a frequency matching the first frequency f 1 or second frequency f 2, and drives the resonant network to cause the transmitting coil to transmit wireless energy; the variable device also includes variable devices n+1~2n, and the variable devices n+1~2n are sequentially arranged on the second side of the transmitting coil opposite to the first side.

[0065] In the second directional wireless power transmission system, each variable device further includes an auxiliary capacitor C 2p and auxiliary capacitor C 2s , where C 2S +C 2P = C2, where the receiving coil and the capacitor C 2p and capacitor C 2s The natural resonant frequency of the series structure is also the second frequency f 2 resonant network; the auxiliary capacitor switch includes a first auxiliary capacitor switch and a second auxiliary capacitor switch, wherein the first auxiliary capacitor switch is used to control the auxiliary capacitor C 1p and auxiliary capacitor C 1s The second auxiliary capacitor switch is used to control the connection and disconnection of the auxiliary capacitor C 2p and auxiliary capacitor C 2s wherein on the second side, the coupling coefficient between the coils is distributed as on the first side; wherein in the case of closing the first main capacitive switch of the transmitting device, the directional wireless power transmission system is at a first frequency f 1 as the operating frequency, when the first auxiliary capacitor switch and the load switch of the variable device 1~n are closed at the same time, the variable device 1~n becomes the receiving device Rx, when the first auxiliary capacitor switch of the variable device 1~n is closed and the load switch is opened, the variable device 1~n becomes the relay device Ix; when the second main capacitor switch of the transmitting device is closed, the directional wireless power transmission system operates at the second frequency f2 as the operating frequency. When the second auxiliary capacitor switches and load switches of the variable devices n+1 to 2n are closed at the same time, the variable devices n+1 to 2n become receiving devices Rx. When the second auxiliary capacitor switches of the variable devices n+1 to 2n are closed and the load switches are opened, the variable devices n+1 to 2n become relay devices Ix.

[0066] In this second directional wireless power transmission system, as an example, the auxiliary control unit controls the switching states of the auxiliary capacitor switch and the load switch as follows: fields a, b, and c are set, and these three fields represent the nth device, capacitor switch, and load switch, respectively. 1 indicates that the capacitor switch or load switch is closed, and 0 indicates that the capacitor switch or load switch is open. At this time, a signal is sent to devices n+1 to 2n through a for loop logic algorithm to close the capacitor switch and load switch: field a = device number j, field b = 1, and field c = 1.

[0067] The above instructions enable the system to form a Harper chain wireless power transmission. When the system charges the load on variable device 1 or variable device n+1, the system sends instructions to variable devices 1 and n+1 in the same way as above to turn them into receiving devices, forming a PT-symmetrical wireless power transmission with the transmitting device.

[0068] The present invention further discloses a directional wireless power transmission method corresponding to the second directional wireless power transmission system, comprising the following steps: the main control unit of the transmitting device and the auxiliary control units of the variable devices 1~n and n+1~2n disconnect the first main capacitor switch, the second main capacitor switch, the first auxiliary capacitor switch, the second auxiliary capacitor switch and the load switch, so that the directional wireless power transmission system is in a standby mode, so that all coils are in a decoupled state, and the voltage and current of the load are collected by the data acquisition unit; the main control unit of the transmitting device determines the load with the minimum voltage as the target load based on the voltage of the load received from the data acquisition unit, and the current of the target load is set to zero when the current of the target load is less than 0. IWhen 0 is zero, the first main capacitor switch or the second main capacitor switch is closed accordingly according to whether the target load is on the first side or the second side to determine the operating frequency of the directional wireless power transmission system, and the target auxiliary control unit of the target variable device where the target load is located is instructed to simultaneously close the auxiliary capacitor switch and the load switch of the target variable device, so that the target variable device becomes a receiving device Rx, and the auxiliary control units of all intermediate variable devices between the transmitting device and the target variable device are instructed to close the auxiliary capacitor switches of all intermediate variable devices, so that all intermediate variable devices become relay devices Ix, thereby charging the target load; when the voltage of the target load reaches a predetermined proportion of its rated voltage, the main control unit of the transmitting device instructs the target auxiliary control unit of the target variable device to simultaneously disconnect the auxiliary capacitor switch and the load switch of the target variable device; the load with the second smallest voltage is determined as the target load, and the above steps are repeated until the voltage of all loads reaches a predetermined proportion of their rated voltage.

[0069] The wireless power transmission system of the present invention, which has a PT symmetric structure and a Harper chain structure, is robust to perturbations of the system parameters because its existence is required by the topological properties of the chain. Unless its symmetry is significantly destroyed, the topological properties of the chain will not change, and thus disordered perturbations within the structure can be ignored. When variable device 1 and variable device n+1 serve as receiving devices, it is a second-order PT-WPT system. The PT-WPT system has a real spectrum and can automatically select the operating frequency corresponding to the highest efficiency, thereby ensuring optimal power transmission over a wide range of transmission distances without any active tuning. When variable devices 2~n and variable devices n+2~2n serve as receiving devices, it is a Harper chain. Because the boundary states are topologically protected, this directional WPT is highly robust to disordered perturbations within the structure and can be equivalent to an equivalent second-order system.

[0070] The above descriptions are merely some preferred embodiments of the present disclosure and illustrate the underlying technical principles. Those skilled in the art should understand that the scope of the invention encompassed by the embodiments of the present disclosure is not limited to technical solutions formed by specific combinations of the aforementioned technical features. It also encompasses other technical solutions formed by any combination of the aforementioned technical features or their equivalents, without departing from the aforementioned inventive concept. For example, a technical solution formed by replacing the aforementioned features with (but not limited to) technical features with similar functions disclosed in the embodiments of the present disclosure.

Claims

1. A directional wireless power transmission system for charging a load, characterized in that: It includes a transmitting device and a variable device, wherein: The transmitting device comprises: Main capacitor C1; The transmitting coil, whose inductor L1 and main capacitor C1 are connected in series to form a natural resonant frequency of the first frequency f 1 resonant network; The inverter circuit is connected to the main capacitor C1 and is used to convert the input DC power into a frequency matching the first frequency. f 1 alternating current, and drives the resonant network to cause the transmitting coil to transmit wireless alternating current energy; Main capacitor switch, used to control the connection and disconnection of the main capacitor C1 and the inverter circuit; The variable device includes variable devices 1 to n..., where n is a natural number greater than 1, and the variable devices 1 to n are sequentially arranged on the first side of the transmitting device, and each variable device includes: Auxiliary capacitor C 1p and auxiliary capacitor C 1s , where C 1S +C 1P =C1; Auxiliary capacitor switch, used to control the auxiliary capacitor C 1p and auxiliary capacitor C 1s connections and disconnections; The receiving coil, its inductance L2 and auxiliary capacitor C 1p and auxiliary capacitor C 1s The natural resonant frequency of the series structure is also the first frequency f 1 resonant network, where the inductance values ​​of inductor L1 and inductor L2 are equal; a rectifier circuit, electrically connected to the receiving coil, for converting the wireless AC power received by the receiving coil into DC power; Load switch, used to control the connection and disconnection of the load and the rectifier circuit; On the first side, the coupling coefficient between the transmitting coil and the receiving coil of the variable device 1 is k1, the coupling coefficient between the receiving coils of the variable device 1 and the variable device 2 is k2, the coupling coefficient between the receiving coils of the variable device 2 and the variable device 3 is k1, the coupling coefficient between the receiving coils of the variable device 3 and the variable device 4 is k2, and so on, where k1<k2; When the main capacitor switch of the transmitting device is closed, the directional wireless power transmission system transmits power at a first frequency. f 1 as the operating frequency. When the auxiliary capacitance switch and the load switch of the variable device are closed at the same time, the variable device becomes the receiving device Rx. When the auxiliary capacitance switch of the variable device is closed and the load switch is opened, the variable device becomes the relay device Ix.

2. The directional wireless power transmission system according to claim 1, characterized in that: The auxiliary capacitor C 1p and the auxiliary capacitor C 1s The capacitance values ​​are equal.

3. The directional wireless power transmission system according to claim 1, characterized in that: The transmitting device further includes a main control unit and a main communication unit, wherein the main control unit is used to control the switching state of the main capacitor switch; The variable device also includes an auxiliary control unit, an auxiliary communication unit and a data acquisition unit. The main communication unit and the auxiliary communication unit are communicatively connected. The data acquisition unit is used to collect the current and voltage of the load. The auxiliary control unit is used to control the switching state of the auxiliary capacitor switch and the load switch based on the current and voltage of the load collected by the data acquisition unit.

4. The directional wireless power transmission system according to claim 3, characterized in that: The main communication unit and the auxiliary communication unit are connected in a wireless manner; the wireless manner includes Bluetooth, WiFi and Zigbee.

5. The directional wireless power transmission system according to claim 3, characterized in that: The variable device also includes: A DC-DC converter, wherein the DC-DC converter includes a switch tube controlled by a PWM signal, and an input end of the DC-DC converter is connected to an output end of the rectifier circuit, and an output end of the DC-DC converter is connected to a load; A PI closed-loop control module, wherein the PI closed-loop control module is electrically connected to the data acquisition unit and the auxiliary control unit, and the input of the PI closed-loop control module is the current and voltage of the load collected by the data acquisition unit and the expected voltage value and the expected current value provided by the auxiliary control unit; A PWM generator, which is controlled by the output of the PI closed-loop control module to provide a desired PWM signal to the DC-DC converter, The main control unit is further configured to calculate an equivalent resistance Req based on the voltage and current of the load, and control the PWM signal through a PI closed-loop control module according to the equivalent resistance Req, so that the DC-DC converter can provide constant current CC charging or constant voltage CV charging for the load.

6. The directional wireless power transmission system according to claim 5, characterized in that: When the equivalent resistance Req is within the range of 0 to the first preset resistance value X1, the main control unit determines the control target of the PI closed-loop control module as current, and controls the PWM signal through the PI closed-loop control module to enable the DC-DC converter to provide constant current CC charging for the load; When the equivalent resistance Req is within the range of the first resistance preset value X1 to the second resistance preset value X2, the main control unit determines the control target of the PI closed-loop control module as voltage, and controls the PWM signal through the PI closed-loop control module so that the DC-DC converter provides constant voltage CV charging for the load.

7. The directional wireless power transmission system according to claim 1, wherein the transmitting device further comprises: Capacitor C2, connected to the inverter circuit; The main capacitor switch includes a first main capacitor switch and a second main capacitor switch, wherein the first main capacitor switch is used to control the connection and disconnection of the capacitor C1 and the inverter circuit, and the second main capacitor switch is used to control the connection and disconnection of the capacitor C2 and the inverter circuit, wherein the transmitting coil and the capacitor C2 are connected in series to form a natural resonant frequency of the second frequency f 2 resonant network; The inverter circuit is used to convert the input direct current into a frequency matching the first frequency f 1 or second frequency f 2 alternating current, and drives the resonant network to cause the transmitting coil to transmit wireless energy; The variable device further includes variable devices n+1 to 2n, which are sequentially arranged on a second side of the transmitting coil opposite to the first side, and each variable device further includes: Auxiliary capacitor C 2p and auxiliary capacitor C 2s , where C 2S +C 2P = C2, where the receiving coil and the capacitor C 2p and capacitor C 2s The natural resonant frequency of the series structure is also the second frequency f 2 resonant network; The auxiliary capacitor switch includes a first auxiliary capacitor switch and a second auxiliary capacitor switch. The first auxiliary capacitor switch is used to control the auxiliary capacitor C 1p and auxiliary capacitor C 1s The second auxiliary capacitor switch is used to control the connection and disconnection of the auxiliary capacitor C 2p and auxiliary capacitor C 2s connections and disconnections; On the second side, the coupling coefficients between the coils are distributed as on the first side; When the first main capacitor switch of the transmitting device is closed, the directional wireless power transmission system transmits power at a first frequency. f 1 as the operating frequency, when the first auxiliary capacitor switch and the load switch of the variable device 1~n are closed at the same time, the variable device 1~n becomes the receiving device Rx, when the first auxiliary capacitor switch of the variable device 1~n is closed and the load switch is opened, the variable device 1~n becomes the relay device Ix; when the second main capacitor switch of the transmitting device is closed, the directional wireless power transmission system operates at the second frequency f 2 as the operating frequency. When the second auxiliary capacitor switches and load switches of the variable devices n+1 to 2n are closed at the same time, the variable devices n+1 to 2n become receiving devices Rx. When the second auxiliary capacitor switches of the variable devices n+1 to 2n are closed and the load switches are opened, the variable devices n+1 to 2n become relay devices Ix.

8. A directional wireless power transmission method, characterized in that: The directional wireless power transmission method is implemented by a directional wireless power transmission system according to any one of claims 1 to 6, comprising the following steps: The main capacitor switch, the auxiliary capacitor switch, and the load switch are all disconnected, so that the directional wireless power transmission system is in a standby mode, and all coils are in a decoupled state. At this time, the voltage and current of the load are collected; According to the collected voltages of the loads, a load with a minimum voltage is determined as a target load; The current at the target load I When 0 is zero, the auxiliary capacitance switch and the load switch of the target variable device where the target load is located are closed at the same time, so that the target variable device becomes the receiving device Rx, and the auxiliary capacitance switches of all intermediate variable devices between the transmitting device and the target variable device are closed, so that all the intermediate variable devices become the relay device Ix; when the voltage of the target load reaches a predetermined proportion of its rated voltage, simultaneously turning off the auxiliary capacitor switch and the load switch of the target variable device; The load with the second smallest voltage is determined as the target load, and the above steps are repeated until the voltages of all loads reach a predetermined proportion of their rated voltages.

9. The directional wireless power transmission method according to claim 8, characterized in that: Setting a first resistance preset value X1 and a second resistance preset value X2, wherein X1 < X2; Calculate the equivalent resistance Req of the load based on the collected voltage and current of the load; When Req is within the range of 0 to X1, the current input to the load is controlled to provide constant current CC charging for the load; When Req is within the range of X1 to X2, the voltage input to the load is controlled to provide constant voltage CV charging for the load.

10. A directional wireless power transmission method, characterized in that: The directional wireless power transmission method is implemented by the directional wireless power transmission system according to claim 7, comprising the following steps: The first main capacitor switch, the second main capacitor switch, the first auxiliary capacitor switch, the second auxiliary capacitor switch, and the load switch are all disconnected, so that the directional wireless power transmission system is in a standby mode, all coils are in a decoupled state, and the voltage and current of the load are collected; According to the collected voltages of the loads, a load with a minimum voltage is determined as a target load; The current at the target load I When 0 is zero, the first main capacitor switch or the second main capacitor switch is closed accordingly according to whether the target load is on the first side or the second side to determine the operating frequency of the directional wireless power transmission system; Simultaneously closing the auxiliary capacitance switch and the load switch of the target variable device where the target load is located, so that the target variable device becomes the receiving device Rx, and closing the auxiliary capacitance switches of all intermediate variable devices between the transmitting device and the target variable device, so that all the intermediate variable devices become the relay device Ix; when the voltage of the target load reaches a predetermined proportion of its rated voltage, simultaneously turning off the auxiliary capacitor switch and the load switch of the target variable device; The load with the second smallest voltage is determined as the target load, and the above steps are repeated until the voltages of all loads reach a predetermined proportion of their rated voltages.

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