Cavity type total-space omnidirectional wireless constant-current charging system

Abstract

The invention relates to the technical field of wireless power transmission, and particularly discloses a cavity type full-space omnidirectional wireless constant-current charging system, which designs a non-closed cavity formed by enclosing more than six regular polygonal planes, a plurality of identical cavity resonant capacitors C1 are connected to different edges of the non-closed cavity to serve as series compensation capacitors of the non-closed cavity, then magnetic field excitation is carried out through a transmitting coil placed in the non-closed cavity, a receiving coil located at any position in the cavity receives electromagnetic waves emitted by the cavity, LC resonance is generated, and the electromagnetic waves emitted by the cavity are compensated. And after being rectified by the rectifier, the electric energy is finally received by the receiving coil and is supplied to a load. According to the system, a compensation topology enabling the system to have a constant current output characteristic is adopted, and constant current output with different load positions, different load sizes and resistance is realized through design of compensation parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless power transmission, and in particular to a cavity-type full-space omnidirectional wireless constant-current charging system. Background Art

[0002] With the development of 5G technology, the era of the Internet of Things (IoT) has arrived. In the future, the intelligence of various daily devices will be greatly improved. There will be hundreds of sensors in a room. How to power these sensor nodes will become one of the keys to the development of IoT technology. The quasi-static field cavity resonant wireless charging system will be a good solution. It achieves wireless power transmission by exciting the mode magnetic field in the resonant cavity and coupling with the receiving coil. Since the magnetic field generated in the resonant cavity is three-dimensionally distributed, the receiver can receive electrical energy almost anywhere inside the resonant cavity. At the same time, this technology can also realize the simultaneous charging of multiple loads, which is extremely flexible and suitable for powering IoT nodes in scenarios such as smart homes in the IoT era.

[0003] Existing research, such as the patent application "Cavity Resonance Wireless Power Transmission System for Three-Dimensional Omnidirectional Wireless Power Transmission" with publication number CN118300284A, can achieve three-dimensional omnidirectional wireless power transmission by controlling the angular position of the two transmitting coils and the phase of the excitation voltage on the two coils, but it requires two transmitting coils, the control is relatively complicated, and it does not analyze in detail the impact of changes in the load end on the system transmission efficiency and capacity. In engineering applications, constant current and constant voltage charging of electronic components is a key measure to ensure that the components are normal and not damaged. Existing research analyzes from the aspects of circuit topology, input impedance angle ZPA, coupling coefficient, etc., and obtains various WPT circuit constant current conditions, but does not analyze how to achieve constant current in a quasi-static field resonant cavity. Summary of the invention

[0004] The present invention provides a cavity-type full-space omnidirectional wireless constant-current charging system, which solves the technical problem of how to simply realize the constant current of a quasi-static field resonant cavity.

[0005] In order to solve the above technical problems, the present invention provides a cavity-type full-space omnidirectional wireless constant current charging system, including a transmitting end, a cavity end and a receiving end; the transmitting end is provided with a transmitting coil L connected P and a transmitting compensation network; the cavity end is provided with a non-enclosed cavity surrounded by more than 6 regular polygonal planes, and a plurality of identical cavity resonant capacitors C1 connected to different edges of the non-enclosed cavity, and 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 The series relay resonant capacitor C TThe receiving end is provided 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, and the shape and size of the polyhedron match the required environmental space, thereby ensuring that the magnetic field of the non-enclosed cavity has as wide coverage as possible and is relatively uniform, while not affecting the communication of communication equipment in the non-enclosed cavity.

[0007] Preferably, the opening cut off when the polyhedron is cut is a polygonal pyramid, and the ratio of each edge length of the polygonal pyramid to the corresponding edge length of the polyhedron is not less than 0.1 and not more than 0.3. The ratio of each edge length of the polygonal pyramid to the corresponding edge length of the polyhedron should not be too large, because too large a ratio will cause the magnetic field radiated by the non-enclosed cavity to fail to cover the entire environmental space, and too small a ratio will cause poor communication of the communication equipment in the environmental space. The ratio can be set between 0.1 and 0.3.

[0008] Preferably, the polyhedron is a regular polyhedron, and when the regular polyhedron is cut, each corner of the regular polyhedron is equally tangent. A regular polyhedron is a special type of polyhedron, and the lengths of the edges are equal, and the lengths of the edges of the cut openings are also equal. The magnetic field distribution in a non-closed cavity is symmetrical along the center, and from the top view of each plane, it is a circular uniform distribution that gradually increases with the distance from the center of the cavity to the cavity wall. The closer to the cavity wall, the stronger the magnetic field, and the closer to the center of the cavity, the weaker the magnetic field.

[0009] Preferably, the polyhedron is a regular hexahedron. A hexahedron structure is often used for general environment spaces, and the polyhedron is a regular hexahedron to match the environment space.

[0010] Preferably, the cavity resonant capacitor C1 is connected to four non-adjacent sides of each hexagon of the non-enclosed cavity. If the positions overlap, only one cavity resonant capacitor C1 is set on the overlapping sides. That is, the cavity resonant capacitor C1 is evenly distributed on different edges of the non-enclosed cavity, which is convenient for calculating the relay resonant capacitor C T , making the circuit operation more stable.

[0011] Preferably, according to the current distribution of the non-enclosed cavity, the transmitting coil L is placed at the location where the regional magnetic flux is maximum. P Place the transmitting coil L at the point where the magnetic flux is the largest in the non-enclosed cavity area. P , so that the transmitting coil L P With non-enclosed cavity L T The degree of coupling is maximized to improve system efficiency.

[0012] Preferably, the relay resonant capacitor C T And the cavity resonant capacitor C1 satisfies the relationship: According to the calculation, the relay resonant capacitor C applied to the regular hexahedron T and the cavity resonant capacitor C1 satisfy the above relationship, so it is convenient to calculate the relay resonant capacitor C according to the cavity resonant capacitor C1. T The size of the resonant parameters is further designed. The transmitting compensation network and the receiving compensation network select 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 compensation network and the receiving compensation network respectively use an S-type network and a P-type network (capacitor parallel compensation network) to achieve the constant current output of the system.

[0013] Preferably, the relay resonant capacitor C T and the relay inductance L T The transmitting compensation network and the receiving compensation network are set to resonate at a frequency f0, where f0 is the operating frequency of the system. Resonating at the operating frequency of the system can make the system have a 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, and the high-frequency inverter is connected to the transmitting coil L P and connected to the transmitting compensation network; the receiving end is also provided with at least a load resistor R L And the rectifier and filter circuit connected thereto.

[0015] The present invention provides a cavity-type full-space omnidirectional wireless constant current charging system. First, a non-enclosed cavity surrounded by more than 6 regular polygonal planes is designed, and multiple identical cavity resonant capacitors C1 are connected on different edges of the non-enclosed cavity as series compensation capacitors of the non-enclosed cavity. Then, a transmitting coil placed in the non-enclosed cavity is used for magnetic field excitation. The non-enclosed cavity receives the magnetic field emitted by the transmitting coil and converts it into electrical energy and performs LC series resonance, further converting the electrical energy into magnetic energy. The full-space omnidirectional radiation is carried out in the non-enclosed cavity. The receiving coil at any position in the cavity receives the electromagnetic wave emitted by the cavity, and LC resonance occurs, converting the magnetic energy into electrical energy. After rectification by the rectifier, it is finally received by the receiving coil and supplies power to the load. Secondly, the system adopts a compensation topology that enables the system to have a constant current output characteristic. By designing the compensation parameters, constant current output at different load positions, different load sizes and resistances is achieved.

[0016] This cavity-type full-space omnidirectional wireless constant-current charging system only requires one transmitting coil and does not require feedback adjustment to achieve constant current output under load changes. It is simple and practical, and provides a new method for how to achieve full-scale and omnidirectional wireless power transmission throughout the house. It is beneficial to improve the convenience and practicality of the medium-distance wireless charging system, and provides a new technical solution for the future wireless charging of the whole-house Internet of Things. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is an equivalent circuit diagram of a cavity-type full-space omnidirectional wireless constant current charging system provided by an embodiment of the present invention;

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

[0019] Figure 3 It is a schematic diagram of the current flow direction corresponding to a cut angle at the cavity end provided by an embodiment of the present invention;

[0020] Figure 4 1 is a diagram showing different receiving coil placement positions (top view in the XY plane) provided by an embodiment of the present invention;

[0021] Figure 5 The receiving coil provided by the embodiment of the present invention is in position 1 and the system output current I changes with the load L Waveform graph;

[0022] Figure 6 The receiving coil provided by the embodiment of the present invention is in position 2 and the system output current I changes with the load L Waveform graph. DETAILED DESCRIPTION

[0023] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limiting the present invention. The accompanying drawings are provided 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] The embodiment of the present invention provides a cavity-type full-space omnidirectional wireless constant current charging system, which includes a transmitting end, a cavity end and a receiving end; the transmitting end is provided with a transmitting coil L connected to the receiving end. P and a transmitting compensation network; the cavity end is provided with a non-enclosed cavity surrounded by more than 6 regular polygonal planes, and a plurality of identical cavity resonant capacitors C1 connected to different edges of the non-enclosed cavity, and 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 TThe series relay resonant capacitor C T The receiving end is provided with at least one set of connected receiving coils L S The transmitting compensation network and the receiving compensation network are selected to have a compensation topology that enables the system to have a constant current output characteristic.

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

[0026] As a complete wireless charging system, the transmitting end of the cavity-type full-space omnidirectional wireless constant current charging system provided in this example is at least equipped with a DC power supply and a high-frequency inverter connected thereto (a MOSFET tube made of GaN material with a switching frequency of up to 1MHz, which makes the system transmission efficiency better and can meet industrial, scientific and medical standards). The high-frequency inverter and the transmitting coil L P It is connected to the transmitting compensation network, where the DC power supply and high-frequency inverter part can be equivalent to the AC source U I The receiving end is also equipped with at least a load resistor R L And the rectifier filter circuit connected thereto, the rectifier filter circuit and the load resistor R L It can be regarded as an equivalent load resistance R eq Therefore, the circuit diagram of the equivalent cavity-type full-space omnidirectional wireless constant current charging system is as follows: Figure 1 shown.

[0027] In order to ensure the uniformity of the internal magnetic field and normal communication, the non-enclosed cavity set in this example can be regarded as the result of cutting off each corner of a fully enclosed polyhedron. The non-enclosed cavity is made of metal (as long as the conductivity is acceptable, the specific metal type is not required, and this example uses a low-cost aluminum thin shell). The shape and size of the polyhedron match the required environmental space, and when cutting the corners, each corner needs to be equally tangent. In order to make the distribution of the internal magnetic field symmetrical, a regular polyhedron can be used, and the cut corners can be regarded as a regular triangular pyramid. Since one face is added for each cut corner, the non-enclosed cavity has the same number of faces as the cut corners compared to the regular polyhedron.

[0028] For general indoor spaces, the polyhedron is a hexahedron, such as Figure 2As shown, the height of the hexahedron is represented by h, the width is represented by d, and the length is represented by l. The eight corners of the hexahedron are tangent to each other to obtain a non-closed cavity in the shape of a tetradecahedron. The shapes of the original six faces have changed from quadrilaterals to octagons, that is, the non-closed cavity is enclosed by these six octagons. The height of the cut opening is represented by h1, the width is represented by d1, and the length is represented by l1 (the length, width, and height of the opening are the lengths of the three edges of the triangular pyramid with the cut surface as the base).

[0029] It is worth mentioning that the size and shape of the non-enclosed cavity can be customized according to the needs (such as the shape and size of the room or container), that is, h, d, and l can be set at will. As for the relationship between the size of the cavity opening and the size of the cavity itself, there are the following restrictions without affecting the transmission efficiency of the system:

[0030]

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

[0032] Determine the connection position of the cavity resonant capacitor C1 (uniform distribution) according to the shape of the non-enclosed cavity and determine the size of the cavity resonant capacitor C1 according to actual needs. Determine the relay resonant capacitor C1 according to the connection position of the cavity resonant capacitor C1 T The equivalent relationship between the cavity resonant capacitor C1 and the relay resonant capacitor C T Finally, the connection is made according to the determined connection position and size of the cavity resonant capacitor C1, and the cavity resonant capacitor C1 can be a chip capacitor that is easy to install.

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

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

[0035]

[0036] Since the currents of each part are equivalent to being connected in parallel, the relay resonant capacitor C T :

[0037]

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

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

[0040]

[0041] in:

[0042] Q1, Q2, Q3, Q L They are the transmitting coil L P , non-enclosed cavity L T , receiving coil L S and the equivalent load resistance R eq The quality factor, Q 3L The receiving coil L S and the equivalent load resistance R eq The coupling quality factor, k 12 , k 23 They are the transmitting coil L P With non-enclosed cavity L T , non-enclosed cavity L T With receiving coil L S The coupling coefficient. From the above formula, we can see that Q2 remains unchanged after the cavity structure is determined, Q L It will change with the load and cannot be predicted. Therefore, in order to improve the system efficiency, it is necessary to increase Q1, Q3, and k as much as possible. 12 , k 23 .

[0043] In order to obtain the maximum driving efficiency, first make k 12 As large as possible, that is, the transmitting coil L P With non-enclosed cavity L T The coupling degree is as high as possible. According to the cavity current distribution, the transmitting coil L is finally placed at the location with the maximum regional magnetic flux. P In order to increase Q1, the transmitting coil L PThe surface area and number of turns should be increased as much as possible without affecting the regional charging freedom (i.e. without causing obstacles to the movement of objects in space), so as to obtain the transmitting coil L P The resistance R P 、Inductance L P .

[0044] In order to simulate the real environment, the receiving coil L S environment and improve system charging efficiency (increase Q3, k 23 ), receiving coil L S The size should be as large as possible without affecting the portability of the charging load. S The resistance R S 、Inductance L S Parameters and transmitting coil L P Same for analysis.

[0045] In the quasi-static cavity wireless energy transmission system, the key parameters that determine the wireless energy transmission are the coupling rate K between the resonators, the quality factor Q of each resonator, and the resonant frequency f0 of the system (the corresponding angular frequency is ω). The derivation formula of the coupling rate K and the coupling coefficient k of the circuit equivalent model is as follows:

[0046] k=2K / ω (5)

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

[0048] By 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-enclosed 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-enclosed cavity L T With receiving coil L S When coupling occurs, there is mutual inductance between the two. When the coupling is weak, the following form is satisfied:

[0052]

[0053]

[0054] K 12 , K 21 and the coupling coefficient k 12 , k 21 The corresponding coupling ratio.

[0055] Rather than a 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 conjugation relationship.

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

[0061]

[0062] From the above formula, we can get:

[0063]

[0064] It can be seen that if and only if , the above formula is valid.

[0065] From the non-enclosed cavity L T Flow to the receiving coil L S Energy P 21 Must be equal to the receiving coil L S The rate of change of energy on the surface with respect to time is:

[0066]

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

[0068]

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

[0070] According to the coupled mode theory, φ 1,2 is time-varying, and the time factor is It can be expressed as a complex function Φ:

[0071]

[0072] The equation P that expresses the two forms 21 They correspond to each other, namely:

[0073]

[0074]

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

[0076]

[0077]

[0078]

[0079] α is the non-enclosed cavity L T The total magnetic energy stored in the receiver coil L S Surface magnetic flux, V is the non-enclosed cavity L T The volume of the receiving coil L S The unit normal vector of the enclosed area, ξ, is the unit normal vector of the non-enclosed cavity L. T Constants related to internal energy storage, H is the non-enclosed cavity L T Internal magnetic field strength. Next, a1 and a2 are normalized, and magnetic energy is characterized by magnetic flux, and then we can get:

[0080]

[0081]

[0082] Since the system resonance ω1=ω2=ω, the coupling ratio K between the resonators can be calculated:

[0083]

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

[0085]

[0086] M PT Indicates the transmitting coil L P With non-enclosed cavity L T The mutual inductance between TS Indicates a non-enclosed cavity L T With receiving coil L S The mutual inductance between them is then obtained. PT and M TS , and finally the circuit equivalent diagram of the three coils can be obtained.

[0087] According to the mutual inductance and resistance between the coils, it is necessary to select the drive transmitting coil L according to the established resonant frequency f0. P And through the determined compensation topology circuit (SSP) and its design parameters, a constant current output at the receiving end is achieved.

[0088] Constant current (CC) charging means that when the load changes (either in nature or in size), the current gain G I does not change, and at the same time, it is also necessary to meet ZPA (i.e. zero phase angle, to ensure the total input impedance Z I is a pure resistor), and the current gain G I , total input impedance Z I The expression is (ignoring the coil and cavity resistance):

[0089]

[0090]

[0091] Among them, the parameters A and B that are customized to simplify the formula expression are:

[0092]

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

[0094]

[0095] That is to say, the compensation capacitance L P and L S .

[0096] The following is an experimental verification.

[0097] The transmitting coil L is set in the experiment P and receiving coil L S They are all hollow squares, with five turns and two layers, inner diameter r1 is 17cm, outer diameter r2 is 21.2cm, and they are wound with excitation wire, with a wire radius of 1mm. P Upper series resonant capacitor C P , in the receiving coil L S Upper parallel resonant capacitor C S , so that it resonates at the system operating frequency f0. At this time, the transmitting coil L P and receiving coil L S The inductance is L = 11.48uH, the resistance is R = 9mΩ, and if the system operating frequency is f0 = 500kHz, the coil should be operated in a resonant state. The resonant capacitor C P and C S Both

[0098] The QSCR cavity is made of 3mm aluminum foil cut and spliced, with cavity height h, width d, length l = 1m, opening height h1, width d1, length l1 = 0.3m, and series compensation capacitor C1 = 600nF on each edge of the cavity. The total equivalent capacitance C of the cavity can be obtained T =800nF, then through The cavity equivalent inductance L can be obtained T =127nH.

[0099] Since the transmitting coil L P and non-enclosed cavity L T Both can be equivalent to RLC series resonant circuit, the receiving coil L S It can be equivalent to an RLC parallel resonant circuit, such as Figure 1As shown. The coupling relationship between each resonant circuit and other circuits is written out through Kirchhoff voltage equation, and then the current in each branch is obtained through matrix circuit equation, and then the voltage gain and system transmission efficiency are obtained. Assume that the transmitting coil L P The position is fixed and the receiving coil L S In such Figure 4 Then, in the transmitting coil L P Front-loaded full-bridge inverter, switching frequency 500kHz, in the receiving coil L S Then load the rectifier, and then change the load resistance and resistance in turn to 5Ω, 10Ω, 15Ω, 20Ω, 20+j4400Ω (1mH), and observe that the output current of the system is basically constant, such as Figure 5 As shown, it is consistent with the calculated and simulated data. Then the receiving coil L is changed S Location to Figure 4 Repeat the above operation for position 2 shown in the figure. The output current is as follows Figure 6 As shown, it can be seen that the output current of the system 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 and will not be disturbed in a very short time.

[0101] In summary, the cavity-type full-space omnidirectional wireless constant current charging system provided by the embodiment of the present invention designs a non-enclosed cavity with a special structure, uses the coupled mode theory to optimize the structure and parameters of the non-enclosed cavity, and studies a circuit topology that can realize constant current charging in the cavity from the circuit direction, and finally realizes a new QSCR charging system structure that can realize multi-position and wide-load constant current wireless charging. The experimental results are in good agreement with the theoretical results, verifying the feasibility of the system.

[0102] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A cavity-type full-space omnidirectional wireless constant current charging system, characterized by: It includes a transmitting end, a cavity end and a receiving end; the transmitting end is provided with a connected transmitting coil L P and a transmitting compensation network; the cavity end is provided with a non-enclosed cavity surrounded by more than 6 regular polygonal planes, and a plurality of identical cavity resonant capacitors C1 connected to different edges of the non-enclosed cavity, and 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 The series relay resonant capacitor C T The receiving end is provided with at least one set of connected receiving coils L S and receiving compensation network.

2. According to claim 1, a cavity-type full-space omnidirectional wireless constant current charging system is characterized by: The non-enclosed cavity is obtained by cutting off each corner of a fully enclosed polyhedron, and the shape and size of the polyhedron match the required environmental space.

3. According to claim 2, a cavity-type full-space omnidirectional wireless constant current charging system is characterized in that: When the polyhedron is beveled, the opening cut out is a polygonal pyramid, and the ratio of each edge length of the polygonal pyramid to the corresponding edge length of the polyhedron is not less than 0.1 and not more than 0.

3.

4. According to claim 3, a cavity-type full-space omnidirectional wireless constant current charging system is characterized in that: The polyhedron is a regular polyhedron, and when the regular polyhedron is cut, each corner of the regular polyhedron is equally tangent.

5. According to claim 4, a cavity-type full-space omnidirectional wireless constant current charging system is characterized in that: The polyhedron is a regular hexahedron.

6. A cavity-type full-space omnidirectional wireless constant current charging system according to claim 5, characterized in that: The cavity resonant capacitor C1 is connected to four non-adjacent sides of each hexagon of the non-enclosed cavity. If there is overlap in position, only one cavity resonant capacitor C1 is provided on the overlapped side.

7. A cavity-type full-space omnidirectional wireless constant current charging system according to claim 6, characterized in that: The relay resonant capacitor C T And the cavity resonant capacitor C1 satisfies the relationship:

8. A cavity-type full-space omnidirectional wireless constant current charging system according to any one of claims 1 to 7, characterized in that: According to the current distribution of the non-enclosed cavity, the transmitting coil L is placed at the location where the regional magnetic flux is maximum. P .

9. A cavity-type full-space omnidirectional wireless constant current charging system according to claim 8, characterized in that: The transmitting compensation network and the receiving compensation network are selected to have a compensation topology that enables the system to have a constant current output characteristic; the relay resonant capacitor C T and the relay inductance L T It is set to resonate at a frequency f0, and the transmitting compensation network and the receiving compensation network are set to resonate at a frequency f0, where f0 is the operating frequency of the system.

10. A cavity-type full-space omnidirectional wireless constant current charging system according to claim 9, characterized in that: The transmitting end is at least provided with a DC power supply and a high-frequency inverter connected thereto, and the high-frequency inverter is connected to the transmitting coil L P and connected to the transmitting compensation network; the receiving end is also provided with at least a load resistor R L And the rectifier and filter circuit connected thereto.

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