A cavity type full-space omnidirectional wireless constant current charging system

Abstract

The application relates to the technical field of wireless power transmission, and particularly discloses a cavity type full-space full-direction wireless constant-current charging system, which is designed as a non-closed cavity surrounded by more than six regular polygonal planes, a plurality of same cavity resonance capacitors C1 are connected on different edges of the non-closed cavity to serve as series compensation capacitors of the non-closed cavity, then a transmitting coil placed in the non-closed cavity is used for magnetic field excitation, a receiving coil at any position in the cavity receives electromagnetic waves emitted by the cavity, LC resonance occurs, magnetic energy is converted into electric energy, the electric energy is rectified by a rectifier, and finally the receiving coil receives the electric energy and supplies power to a load. The system adopts a compensation topology which enables the system to have a constant-current output characteristic, and through the design of compensation parameters, constant-current output can be realized at different load positions, different load sizes and different resistances.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and in particular to a cavity-type all-space omnidirectional wireless constant current charging system. Background Technology

[0002] With the development of 5G technology and the arrival of the Internet of Things (IoT) era, the intelligence of various everyday devices will be greatly enhanced. A single room may contain hundreds of sensors. How to power these sensor nodes will become a key aspect of IoT technology development. Quasi-static field cavity resonant wireless charging systems offer a good solution. This system achieves wireless power transmission by exciting a modal magnetic field within the resonant cavity and coupling it with a receiving coil. Because the magnetic field generated within the resonant cavity is three-dimensionally distributed, the receiver can receive power from almost any location within the cavity. Furthermore, this technology allows for simultaneous charging of multiple loads, offering exceptional flexibility and making it suitable for powering IoT nodes in smart home and other IoT scenarios in the IoT era.

[0003] Existing research, such as the patent application CN118300284A entitled "Cavity Resonant Wireless Power Transfer System for Three-Dimensional Omnidirectional Wireless Power Transfer," achieves three-dimensional omnidirectional wireless power transfer by controlling the angular positions of two transmitting coils and the phase of the excitation voltages on the two coils. However, it requires two transmitting coils, making control complex, and it does not analyze in detail the impact of load changes on the system's transmission efficiency and capability. In engineering applications, constant current and constant voltage charging of electronic components is a key measure to ensure the components function normally and are not damaged. Existing research analyzes various constant current conditions for WPT circuits from aspects such as circuit topology, input impedance angle ZPA, and coupling coefficient, but it does not analyze how to achieve constant current in a quasi-static field resonant cavity. Summary of the Invention

[0004] This invention provides a cavity-type all-space omnidirectional wireless constant current charging system, which solves the technical problem of how to easily achieve constant current in a quasi-static field resonant cavity.

[0005] To address the above technical problems, this invention provides a cavity-type omnidirectional wireless constant current charging system, comprising a transmitter, a cavity, and a receiver; the transmitter is equipped with a connected transmitting coil L. P The cavity end is provided with a non-enclosed cavity enclosed by more than 6 regular polygonal planes, and multiple identical cavity resonant capacitors C1 connected to different edges of the non-enclosed cavity. The non-enclosed cavity is equivalent to a relay inductor L. T The plurality of cavity resonant capacitors C1 are equivalent to the relay inductor L. T Series relay resonant capacitor C TThe receiving end is equipped with at least one set of connected receiving coils L. S and receiving compensation network.

[0006] Preferably, the non-enclosed cavity is obtained by cutting off each corner of a fully enclosed polyhedron. The shape and size of the polyhedron match the required environmental space, thus ensuring that the magnetic field of the non-enclosed cavity covers as wide and as uniformly as possible, without affecting the communication of the communication equipment inside the non-enclosed cavity.

[0007] Preferably, the opening cut when chamfering the polyhedron is a multi-faceted pyramid, and the ratio of the length of each edge of the multi-faceted pyramid to the corresponding edge of the polyhedron is not less than 0.1 and not more than 0.3. The ratio of the length of each edge of the multi-faceted pyramid to the corresponding edge of the polyhedron should not be too large, as a large ratio will prevent the magnetic field radiated by the non-enclosed cavity from covering the entire environmental space, while a small ratio will result in poor communication of communication devices within the environmental space. The ratio can be set between 0.1 and 0.3.

[0008] Preferably, the polyhedron is a regular polyhedron, and when truncating the regular polyhedron, each corner of the regular polyhedron is equally tangent. A regular polyhedron is a special type of polyhedron in which all its edges are of equal length, and the edges of all the cut openings are also of equal length. The magnetic field distribution within the non-sealed cavity is symmetrical along the center, and when viewed from any plane, it is a uniformly distributed ring that gradually increases in distance from the cavity center to the cavity wall. The magnetic field is stronger closer to the cavity wall and weaker closer to the cavity center.

[0009] Preferably, the polyhedron is a regular hexahedron. Since hexahedral structures are commonly used in general environmental spaces, the use of a regular hexahedron in the polyhedron is appropriate for the environmental space.

[0010] Preferably, the cavity resonant capacitor C1 is connected to the four non-adjacent sides of each hexagon in the unclosed cavity. If there is overlap, only one cavity resonant capacitor C1 is installed on the overlapping side. That is, the cavity resonant capacitors C1 are evenly distributed on different edges of the unclosed cavity, which facilitates the calculation of the relay resonant capacitor C. T This makes the circuit operation more stable.

[0011] Preferably, the transmitting coil L is placed at the location of maximum regional magnetic flux, based on the current distribution of the non-enclosed cavity. P The transmitting coil L is placed at the point of maximum magnetic flux in the non-enclosed cavity region. P This makes the transmitting coil L P With non-closed cavity L T The coupling is maximized to improve system efficiency.

[0012] Preferably, the relay resonant capacitor C T The cavity resonant capacitor C1 satisfies the following relationship: Based on calculations, the relay resonant capacitor C applied to the regular hexahedron... T The cavity resonant capacitor C1 satisfies the above relationship, thus the relay resonant capacitor C can be easily calculated based on the cavity resonant capacitor C1. T The size of the resonance parameters is further considered to design the system. The transmitting and receiving compensation networks are selected with compensation topologies that enable the system to have constant current output characteristics. Here, the relay compensation network is an S-type network (capacitor series compensation network), and the transmitting and receiving compensation networks can achieve constant current output by using S-type and P-type networks (capacitor parallel compensation networks) respectively.

[0013] Preferably, the relay resonant capacitor C T and the relay inductor L T The transmitting compensation network and the receiving compensation network are configured to resonate at frequency f0, where f0 is the system's operating frequency. Resonance at the system's operating frequency allows the system to achieve higher transmission efficiency.

[0014] Preferably, the transmitting end is further provided with at least a DC power supply and a high-frequency inverter connected thereto, the high-frequency inverter and the transmitting coil L P The receiver is connected to the transmission compensation network; the receiver also has at least a load resistor R. L and the rectifier and filter circuit connected to it.

[0015] This invention provides a cavity-type omnidirectional wireless constant current charging system. First, a non-enclosed cavity is designed, enclosed by six or more regular polygonal planes. Multiple identical cavity resonant capacitors C1 are connected to different edges of the non-enclosed cavity as series compensation capacitors. Then, a transmitting coil placed inside the non-enclosed cavity is used for magnetic field excitation. The non-enclosed cavity receives the magnetic field emitted by the transmitting coil, converts it into electrical energy, and performs LC series resonance. This electrical energy is further converted into magnetic energy and radiated omnidirectionally throughout the cavity. A receiving coil located at any position within the cavity receives the electromagnetic waves emitted by the cavity, undergoes LC resonance, converts the magnetic energy into electrical energy, and after rectification by a rectifier, is finally received by the receiving coil and supplies power to the load. Secondly, the system employs a compensated topology that enables constant current output characteristics. Through the design of compensation parameters, constant current output is achieved under different load locations, load sizes, and resistivity.

[0016] This cavity-type omnidirectional wireless constant current charging system requires only one transmitting coil and no feedback adjustment to achieve constant current output under load changes. It is simple and practical, providing a new method for achieving omnidirectional wireless power transmission throughout the house. It is conducive to improving the convenience and practicality of mid-range wireless charging systems and provides a new technical solution for future whole-house IoT-enabled wireless charging. Attached Figure Description

[0017] Figure 1 This is an equivalent circuit diagram of the cavity-type all-space omnidirectional wireless constant current charging system provided in the embodiments of the present invention;

[0018] Figure 2 This is a structural diagram of the cavity end of a cavity-type all-space omnidirectional wireless constant current charging system provided in an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the current flow direction corresponding to a chamfer at the cavity end provided in an embodiment of the present invention;

[0020] Figure 4 These are different receiving coil placement positions provided in embodiments of the present invention (XY plane top view);

[0021] Figure 5 The system output current I provided in this embodiment of the invention is as the load changes when the receiving coil is in position 1. L Waveform diagram;

[0022] Figure 6 The system output current I provided in this embodiment of the invention is as the load changes when the receiving coil is in position 2. L Waveform diagram. Detailed Implementation

[0023] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the present invention. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0024] This invention provides a cavity-type omnidirectional wireless constant current charging system, comprising a transmitter, a cavity, and a receiver; the transmitter is equipped with a connected transmitting coil L. P The cavity end is provided with a non-enclosed cavity enclosed by more than 6 regular polygonal planes, and multiple identical cavity resonant capacitors C1 connected to different edges of the non-enclosed cavity. The non-enclosed cavity is equivalent to a relay inductor L. T The plurality of cavity resonant capacitors C1 are equivalent to the relay inductor L. TSeries relay resonant capacitor C T The receiving end is equipped with at least one set of connected receiving coils L. S The transmit compensation network and the receive compensation network are selected to provide the system with constant current output characteristics through a compensation topology.

[0025] The cavity-type omnidirectional wireless constant current charging system described in this example adopts an SSP-type compensation topology to achieve constant current output, that is, the transmitter compensation network adopts the same structure as the transmitter coil L. P Series-connected emission compensation capacitor C P The receiving compensation network adopts the same as the receiving coil L S Series-connected receiving compensation capacitor C S .

[0026] As a complete wireless charging system, the transmitter of the cavity-type omnidirectional wireless constant current charging system provided in this example is equipped with at least a DC power supply and a high-frequency inverter connected to it (using GaN material MOSFETs, with a switching frequency of up to 1MHz, resulting in better system transmission efficiency and meeting industrial, scientific, and medical standards). The high-frequency inverter and the transmitting coil L... P Connected to the transmit compensation network, the DC power supply and high-frequency inverter sections can be equivalent to AC source U. I The receiving end also has at least a load resistor R. L and the rectifier and filter circuit connected thereto, the rectifier and filter circuit and the load resistor R L It can be viewed as an equivalent load resistance R. eq Therefore, the circuit diagram of the equivalent cavity-type all-space omnidirectional wireless constant current charging system is as follows: Figure 1 As shown.

[0027] To ensure the uniformity of the internal magnetic field and normal communication, the non-enclosed cavity in this example can be considered as the result of cutting off each corner of a fully enclosed polyhedron. The non-enclosed cavity is made of metal (any metal with sufficient conductivity is acceptable; the specific type is not required, and in this example, a low-cost aluminum shell is used). The shape and size of the polyhedron are matched to the required environmental space, and each corner must be equally tangent during the cutting process. To ensure a symmetrical distribution of the internal magnetic field, a regular polyhedron can be used, and the cut-off corners can be considered as a regular triangular pyramid. Since each cut corner adds a face, the non-enclosed cavity has the same number of faces as the cut corners compared to a regular polyhedron.

[0028] For typical interior spaces, a polyhedron is a hexahedron, such as... Figure 2As shown, the height of the hexahedron is denoted as h, the width as d, and the length as l. By tangenting the eight corners of the hexahedron, a non-closed cavity in the shape of a fourteen-sided pyramid is obtained. The original six faces change shape, transforming from quadrilaterals to octagons; that is, the non-closed cavity is formed by these six octagons. The height of the cut opening is denoted as h1, the width as d1, and the length as l1 (the length, width, and height of the opening are the lengths of the three edges of the triangular pyramid with the cut face as its base).

[0029] It is worth mentioning that the size and shape of the non-enclosed cavity can be customized according to requirements (such as the shape and size of a room or container), meaning that h, d, and l can be arbitrarily chosen. Regarding the relationship between the cavity opening size and the cavity's overall size, the following constraints apply without affecting system transmission efficiency:

[0030]

[0031] The ratio of the length of each edge of the pyramid to the corresponding edge length of the polyhedron should not be too large. If it is too large, the magnetic field radiated by the non-enclosed cavity will not be able to cover the entire environmental space. If it is too small, communication equipment in the environmental space will have poor communication. The ratio can be set between 0.1 and 0.3. In order to save materials and reduce costs, the ratio of the length of each opening to the length of each edge of the cavity is set to 0.3 in this example.

[0032] The connection positions (uniformly distributed) of the cavity resonant capacitor C1 are determined based on the shape of the non-enclosed cavity, and the size of the cavity resonant capacitor C1 is determined according to actual needs. The relay resonant capacitor C is then determined based on the connection positions of the cavity resonant capacitor C1. T Based on the equivalent relationship between the cavity resonant capacitor C1 and the relay resonant capacitor C, the relay resonant capacitor C can be determined. T The size of the cavity resonant capacitor C1 is then determined. Finally, the connections are made according to the specified location and size. The cavity resonant capacitor C1 can be a surface-mount capacitor for easy installation.

[0033] by Figure 2 Taking the unclosed cavity shown as an example, the connection positions of the cavity resonant capacitor C1 are as follows: if the positions overlap on the four non-adjacent sides of each hexagon of the unclosed cavity, only one cavity resonant capacitor C1 is set on the overlapping side. Therefore, a total of 12 cavity resonant capacitors C1 are set on the unclosed cavity.

[0034] like Figure 3 As shown in the current flow diagram, since the current flows clockwise or counterclockwise at each opening, the non-closed cavity can be analyzed in eight parts. Analyzing one of the eight parts, it can be seen that the current passes through three capacitor segments along its flow path, and only half of each capacitor segment is traversed. Therefore, the circuit equivalent capacitance C of half of each capacitor segment is... T1 for:

[0035]

[0036] Since the currents in each part are equivalent to those in parallel at this time, the relay resonant capacitor C... T :

[0037]

[0038] The resonant frequency f0 of the non-enclosed cavity is set as the operating frequency of the system. According to the resonance formula... The self-inductance L of a non-closed cavity can be obtained. T .

[0039] According to the reflection impedance theory, at the system operating frequency f0, the system efficiency of the equivalent three-coil circuit can be calculated by the following formula (ignoring the coupling between the transmitting and receiving coils):

[0040]

[0041] in:

[0042] Q1, Q2, Q3, Q L These are the transmitting coils L P Non-enclosed cavity L T Receiver coil L S and equivalent load resistance R eq The quality factor, Q 3L For receiving coil L S and equivalent load resistance R eq The coupling quality factor, k 12 k 23 These are the transmitting coils L P With non-closed cavity L T Non-enclosed cavity L T With receiving coil L S The coupling coefficient. From the above equation, it can be seen that Q2 remains unchanged after the cavity structure is determined. L The load changes unpredictably, so to improve system efficiency, it is necessary to increase Q1, Q3, and k as much as possible. 12 k 23 .

[0043] To achieve maximum driving efficiency, first make k 12 Make it as large as possible, that is, make the transmitting coil L P With non-closed cavity L T The coupling degree should be as high as possible. Based on the cavity current distribution, the transmitting coil L is ultimately placed at the location of the maximum regional magnetic flux. P To increase Q1, the transmitting coil L... PThe surface area and number of turns of the transmitting coil should be increased as much as possible without affecting the degree of freedom of charging in the region (i.e., without hindering the movement of objects in space), thereby obtaining the transmitting coil L. P resistance R P Inductor L P .

[0044] To simulate the receiving coil L under real-world conditions S The environment and improving system charging efficiency (increasing Q3, k 23 ), receiving coil L S The size should be determined by the principle of being as large as possible without compromising the portability of the charging load. In this example, we assume the receiving coil has a coil size of L. S resistance R S Inductor L S Equal parameters and transmitting coil L P The same is true for analysis purposes.

[0045] In a quasi-static cavity wireless power transmission system, the key parameters determining wireless power transmission are the coupling ratio K between resonators, the quality factor Q of each resonator, and the system's resonant frequency f0 (corresponding to the angular frequency ω). The derivation formulas for the coupling ratio K and the coupling coefficient k in the circuit equivalent model are as follows:

[0046] k=2K / ω (5)

[0047] Therefore, by obtaining the coupling ratio K, the coupling coefficient k of the circuit equivalent model can be obtained.

[0048] Using coupled-mode theory, this example defines a non-closed cavity L. T The electric field amplitude and resonant frequency are a1 and ω1, and the receiving coil L S The electric field amplitude and resonant frequency are a2 and ω2, and the time factor is... (e is the natural base). Therefore, the non-closed cavity L T The electric field a1(t) and the receiving coil L S The electric field a2(t) has the following form:

[0049]

[0050]

[0051] When the non-closed cavity L T With receiving coil L S When coupling occurs, there is mutual inductance between the two. When the coupling is weak, it satisfies the following form:

[0052]

[0053]

[0054] K 12 K 21 They are respectively with the coupling coefficient k 12 k 21 The corresponding coupling rate.

[0055] Non-closed cavity L T The total energy can be expressed as:

[0056] W = |a1| 2 +|a2| 2 (10)

[0057] in:

[0058]

[0059] "*" indicates a complex conjugate relationship.

[0060] According to the law of conservation of energy:

[0061]

[0062] From the above formula, we get:

[0063]

[0064] It is evident that if and only if Only then will the above equation hold true.

[0065] From the non-closed cavity L T Flow to receiving coil L S Energy P 21 It must be equal to the receiving coil L S The rate of change of energy over time, i.e.:

[0066]

[0067] At the same time, P 21 It is equal to the product of the rate of change of magnetic flux in the receiving coil circuit and the coil current, that is:

[0068]

[0069] φ1 is in resonant mode, passing through the receiving coil L S The instantaneous magnetic flux, φ2 is the receiving coil L S The current i2 generated passes through the receiving coil L S The magnetic flux (opposite to φ1).

[0070] According to coupled-mode theory, φ 1,2 It changes over time, and the time factor is also... It can be expressed using the complex function Φ as:

[0071]

[0072] Equation P expressed in two forms 21 They are respectively equal, that is:

[0073]

[0074]

[0075] If we want to obtain the coupling rate K using the above two equations, we need to normalize a1 and a2 so that |a1| 2 and |a2| 2 It equals the initially defined value, i.e., |a1| 2 L is a non-closed cavity T The total magnetic energy in the resonant mode, |a2| 2 For receiving coil L S The total magnetic energy in resonant mode. Three key variables are defined below for equation substitution:

[0076]

[0077]

[0078]

[0079] α is a non-closed cavity L T The total magnetic energy stored internally, β, is received by the receiving coil L. S The magnetic flux on the surface, V is the magnetic flux of the non-closed cavity L. T The volume of the receiving coil, n is the volume of the receiving coil L. S The unit normal vector ξ enclosing the area is related to the non-closed cavity L. T The constants related to internal energy storage, where H is the non-closed cavity L T The internal magnetic field strength. Next, a1 and a2 are normalized, and magnetic energy is characterized by magnetic flux, resulting in:

[0080]

[0081]

[0082] Since the system resonates with ω1=ω2=ω, the coupling rate K between the resonators can be calculated:

[0083]

[0084] Using the relationship between coupling coefficient and mutual inductance:

[0085]

[0086] M PT Indicates transmitting coil L P With non-closed cavity L T Mutual intuition between them, M TS L represents a non-closed cavity T With receiving coil L S The mutual induction between them leads to the mutual induction M. PT and M TS Finally, the equivalent circuit diagram of the three coils can be obtained.

[0087] Based on the calculated mutual inductance and resistance values ​​between the coils, the driving and transmitting coil L needs to be selected according to the predetermined resonant frequency f0. P And through the determined compensation topology circuit (SSP) and its design parameters, a constant current output is achieved at the receiving end.

[0088] Constant current (CC) charging refers to the charging process where the current gain G changes as the load changes (either in nature or magnitude). I The input impedance must remain unchanged, and at the same time, it must satisfy ZPA (i.e., zero phase angle, ensuring the total input impedance Z). I (It is a pure resistor), while the current gain G I Total input impedance Z I The expression is (ignoring coil and cavity resistance):

[0089]

[0090]

[0091] To simplify the formula expression, the custom parameters A and B are:

[0092]

[0093] X P X T X S X represents the equivalent reactance of the three coil circuits, respectively. S1 and X S2 X represents the equivalent reactance of the inductor circuit and the equivalent reactance of the capacitor circuit at the receiving end. PT X TS These represent the transmitting coil L. P With non-sealed cavity L T Non-sealed cavity L T With receiving coil L S The mutual inductance between them, U I I I The transmitting coil L is respectively P Input voltage and current, U o I oThe receiving coil L is respectively S The output voltage and current. According to Kirchhoff's principle, when X... P =0,X S1 +X S2 When =0, the above expression simplifies to:

[0094]

[0095] That is, the compensation capacitor L is obtained. P and L S .

[0096] The following experiment will verify this.

[0097] The experiment sets up a transmitting coil L P and receiving coil L S All are hollow squares, with a five-turn, two-layer structure. The inner diameter r1 is 17cm, and the outer diameter r2 is 21.2cm. They are wound with excitation wire, and the radius of the wire is 1mm. In the transmitting coil L... P upper series resonant capacitor C P In the receiving coil L S Upper parallel resonant capacitor C S This causes the transmitting coil L to resonate at the system's operating frequency f0. P and receiving coil L S The inductance of each coil is L = 11.48uH, and the resistance is R = 9mΩ. Assuming the system operating frequency is f0 = 500kHz, the resonant capacitance C should be [value missing] to make the coil operate in resonance. P and C S All

[0098] The QSCR cavity is constructed from 3mm thin aluminum sheet, cut and assembled. The cavity height h, width d, and length l = 1m, and the opening height h1, width d1, and length l1 = 0.3m. A compensation capacitor C1 = 600nF is connected in series on each edge of the cavity. (Based on the above formula...) The total equivalent capacitance C of the cavity can be calculated. T =800nF, then through The equivalent inductance L of the cavity can be obtained. T =127nH.

[0099] Due to the transmitting coil L P Non-closed cavity L T Both can be equivalent to an RLC series resonant circuit, with the receiving coil L... S It can be equivalent to an RLC parallel resonant circuit, such as Figure 1As shown. The coupling relationships between each resonant circuit and other circuits are derived using Kirchhoff's voltage equations. Then, the current in each branch is calculated using matrix circuit equations, leading to the voltage gain and system transmission efficiency. Assume the transmitting coil L... P The position remains fixed, and the receiving coil L S In such Figure 4 Position 1 is shown. Next, at the transmitting coil L... P A preloaded full-bridge inverter with a switching frequency of 500kHz is used in the receiving coil L. S After loading the rectifier, the load resistance and resistivity were changed sequentially to 5Ω, 10Ω, 15Ω, 20Ω, and 20+j4400Ω (1mH). The output current of the system remained essentially constant. Figure 5 As shown, this matches the calculated and simulated data. Then, the receiving coil L was changed. S Location to Figure 4 For position 2 shown, repeat the above operation; its output current is as follows: Figure 6 As shown, the system's output current is basically constant.

[0100] The above experiments confirm the constant current characteristic of the system, that is, when the load resistance and resistivity are changed at any position, the load current will reach a constant value in a very short time and remain undisturbed.

[0101] In summary, the cavity-type omnidirectional wireless constant current charging system provided by this invention designs a specially structured non-sealed cavity, optimizes the cavity structure and parameters using coupled-mode theory, and studies a circuit topology that enables constant current charging within the cavity from a circuit perspective. This ultimately achieves a novel QSCR charging system structure capable of multi-position, wide-load constant current wireless charging. Experimental results agree well with theoretical results, verifying the feasibility of the system.

[0102] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A cavity-type omnidirectional wireless constant current charging system, characterized in that: It includes a transmitter, a cavity, and a receiver; the transmitter is equipped with a connected transmitting coil. L P And a transmission compensation network; the cavity end is provided with a non-closed cavity enclosed by 6 regular polygonal planes, and multiple identical cavity resonant capacitors connected to different edges of the non-closed cavity. C 1. The non-enclosed cavity is equivalent to a relay inductor. L T Multiple cavity resonant capacitors C 1 is equivalent to the relay inductor. L T Series relay resonant capacitor C T The receiving end is equipped with at least one set of connected receiving coils. L S and receiving compensation network; The non-enclosed cavity is obtained by making each corner of a fully enclosed regular hexahedron equally tangent, and the size of the regular hexahedron matches the required environmental space. When the regular hexahedron is chamfered, the cut-out opening is a multi-faceted pyramid, and the ratio of the length of each edge of the multi-faceted pyramid to the corresponding edge length of the regular hexahedron is not less than 0.1 and not greater than 0.

3. The cavity resonant capacitor C 1. Connect the four non-adjacent sides of each octagon in the non-enclosed cavity. If the positions overlap, only one cavity resonant capacitor is set on the overlapping side. C 1; Based on the current distribution in the unclosed cavity, the transmitting coil is placed at the location of maximum regional magnetic flux. L P ; The transmit compensation network and the receive compensation network are selected with compensation topologies that enable the system to have constant current output characteristics; the relay resonant capacitor C T and the relay inductor L T Set at frequency f 0 resonance, the transmit compensation network and the receive compensation network are configured to operate at frequency 0. f 0 resonance, f 0 represents the system's operating frequency.

2. The cavity-type all-space omnidirectional wireless constant current charging system according to claim 1, characterized in that, The relay resonant capacitor C T and the cavity resonant capacitor C 1. Satisfying the relation: .

3. The cavity-type all-space omnidirectional wireless constant current charging system according to claim 1, characterized in that: The transmitting end is also equipped with at least a DC power supply and a high-frequency inverter connected thereto, the high-frequency inverter and the transmitting coil. L P The receiver is connected to the transmission compensation network; the receiver also has at least a load resistor. R L and the rectifier and filter circuit connected to it.

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