Multi-pickup single-capacitor coupling unmanned aerial vehicle wireless charging system under three-dimensional electric field

Abstract

The invention discloses a multi-pickup single-capacitor coupling unmanned aerial vehicle wireless charging system in a three-dimensional electric field, and relates to the field of wireless electric energy transmission, and the system comprises a charging unit which comprises a DC power supply, an inverter connected with the output end of the DC power supply, and a primary side resonance compensation circuit connected with the output end of the inverter; the coupling electric field is connected with the output end of the primary side resonance compensation circuit, and the coupling electric field comprises a transmitting end and a plurality of groups of receiving ends; the unmanned aerial vehicle unit is connected with the charging unit through the coupling electric field; the unmanned aerial vehicle unit comprises a plurality of groups of secondary side output circuits and a battery piece connected with the output end of the secondary rectifier; the secondary side output circuit comprises a secondary side resonance compensation circuit and a secondary rectifier connected with the output end of the secondary side resonance compensation circuit; wherein the receiving end is electrically connected with the primary side resonance compensation circuit, and the receiving end is electrically connected with the plurality of groups of secondary side resonance compensation circuits respectively.

Description

Technical Field

[0001] The present invention relates to the field of wireless power transmission, and in particular to a multi-pickup single capacitor coupling unmanned aerial vehicle wireless charging system under a three-dimensional electric field. Background Art

[0002] Wireless charging technology is simple, convenient and easy to automate. At present, the near-field coupling commonly used in wireless power transmission technology is mainly divided into magnetic field coupling wireless power transmission (IPT) and electric field coupling wireless power transmission (CPT). Compared with the weight and cost issues that are difficult to bypass with electromagnetic coupling wireless power transmission technology, electric field coupling wireless power transmission technology has the following advantages: the coupling mechanism is simple and thin, the shape is changeable, and the cost is low; the overall electromagnetic radiation of the EC-WPT system is low; the eddy current formed on the metal is very small; it can transfer energy across the metal, etc.

[0003] However, most of the current research on EC-WPT systems uses two pairs of metal plates, which leads to problems such as poor flexibility of mobile electrical equipment under the constraints of two pairs of metal plates. The single capacitor electric field coupling wireless power transmission system can solve the above problems. In the actual application of the single capacitor coupling EC-WPT system, there are two transmission modes: fixed-point energy transmission and dynamic energy transmission. The experimental phenomenon of single capacitor coupling wireless power transmission technology (SCC-WPT) is that wireless power transmission is achieved with only one pair of metal bodies. It is defined as a wireless power transmission technology that uses electric field as the main power transmission carrier, utilizes the coupling capacitance and self-capacitance formed by the metal body, and the stray capacitance of the system components and lines to the ground, or forms a complete electrical circuit through the coupling capacitance formed by the metal body and the ground.

[0004] SCC-WPT technology is developed based on the traditional EC-WPT technology. It not only uses the coupling capacitance formed between metal plates, but also forms a complete electrical connection loop through the self-capacitance of metal plates and the stray capacitance of system components and lines to the ground. In this way, wireless transmission of electric energy can be achieved while reducing metal plates. This technology can not only improve the coupling capacitance of the coupling mechanism, but also has the advantage of avoiding the influence of cross-coupling capacitance in traditional EC-WPT systems. It has great potential in the flexible charging / power supply system of two-dimensional planar mobile devices. Summary of the invention

[0005] In view of the problems existing in the existing wireless charging system, the present invention is proposed.

[0006] Therefore, the problem to be solved by the present invention is that the use of two pairs of metal plates leads to the problem that the mobile electrical equipment has poor flexibility under the restriction of the two pairs of metal plates.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, an embodiment of the present invention provides a multi-pickup single capacitor coupling UAV wireless charging system under a three-dimensional electric field, which includes:

[0009] A charging unit, comprising a DC power supply, an inverter connected to an output end of the DC power supply, and a primary resonance compensation circuit connected to an output end of the inverter;

[0010] A coupling electric field connected to the output end of the primary resonance compensation circuit, wherein the coupling electric field includes a transmitting end and multiple groups of receiving ends;

[0011] A drone unit is connected to the charging unit through the coupling electric field; the drone unit includes a plurality of secondary output circuits, and a battery component connected to the output end of the secondary output circuit; the secondary output circuit includes a secondary resonance compensation circuit and a secondary rectifier connected to the output end of the secondary resonance compensation circuit;

[0012] Wherein, the receiving end is electrically connected to the primary resonance compensation circuit, and the receiving end is electrically connected to multiple groups of secondary resonance compensation circuits respectively.

[0013] As a preferred solution of the multi-pickup single capacitor coupling UAV wireless charging system under the three-dimensional electric field of the present invention, wherein: the primary side resonance compensation circuit and the secondary side resonance compensation circuit are symmetrically arranged LC resonance topology structures;

[0014] The primary resonance compensation circuit includes a primary compensation inductor and a primary compensation capacitor; the secondary resonance compensation circuit includes a secondary compensation inductor and a secondary compensation capacitor.

[0015] As a preferred solution of the multi-pickup single-capacitive coupling UAV wireless charging system under the three-dimensional electric field of the present invention, wherein: the coupling electric field includes multiple capacitive couplers, and the multiple capacitive couplers share the same transmitting end;

[0016] The capacitive coupler includes a coupling capacitor, a mutual capacitor and a ground capacitor;

[0017] The coupling electric field controls the output port to output a constant current that is not affected by the load through a coupling equivalent model;

[0018] The equivalent input capacitance of the coupling equivalent model is determined as follows:

[0019]

[0020] Among them, C in,pri , C in,sec1 , C in,sec2 and C in,sec3is the equivalent input capacitance of the coupling equivalent model, I1 is the output current of the charging unit, U1 is the output voltage of the charging unit, I2 is the output current of the first secondary output circuit, U2 is the output voltage of the first secondary output circuit, I3 is the output current of the second secondary output circuit, U3 is the output voltage of the second secondary output circuit, I4 is the output current of the third secondary output circuit, U4 is the output voltage of the third secondary output circuit, C a1 , C a2 , C a3 , C b1 , C b2 , C b3 , C c1 , C c2 , C c3 is the capacitance after conversion from stray capacitance coupling model to Π model.

[0021] As a preferred solution of the multi-pickup single capacitor coupling UAV wireless charging system under the three-dimensional electric field of the present invention, the capacitance after conversion from the stray capacitance coupling model to the Π model is determined by the following formula:

[0022]

[0023] Among them, C 11 is the capacitance of the transmitting plate to ground, C ex1 is the capacitance of the charging unit to ground, C 12 is the capacitance between the plate at the transmitting end and the plate at the first receiving end, C 22 is the capacitance of the plate of the first receiving end to ground, C ex2 is the capacitance to ground of the first secondary output circuit, C 33 is the capacitance of the plate of the second receiving end to ground, C ex3 is the capacitance to ground of the second secondary output circuit, C 13 is the capacitance between the plate at the transmitting end and the plate at the second receiving end, C 44 is the capacitance of the plate of the third receiving end to ground, C ex4 is the capacitance to ground of the third secondary output circuit, C 14 is the capacitance between the plate at the transmitting end and the plate at the third receiving end.

[0024] As a preferred solution of the multi-pickup single capacitor coupling UAV wireless charging system under the three-dimensional electric field of the present invention, wherein: the coupled electric field adjusts the passive resonant element through the coupling equivalent model to make the charging system reach a resonant state;

[0025] The adjustment of the passive resonant element is shown in the following equation:

[0026]

[0027] Among them, L p and C p They are the primary compensation inductor and primary compensation capacitor, L s1 and C s1 are the secondary compensation inductor and capacitor of the first secondary output circuit, L s2 and C s1 are the secondary compensation inductor and capacitor of the second secondary output circuit, L s3 and C s3 They are respectively the secondary side compensation inductor and the secondary side compensation capacitor of the third secondary side output circuit.

[0028] As a preferred solution of the multi-pickup single capacitor coupling UAV wireless charging system under the three-dimensional electric field of the present invention, when the charging system reaches the resonant state, the output current and output power of the charging system are shown as follows:

[0029]

[0030] Among them, U in is the inverter output voltage, U out is the system output voltage, I o is the system output current, P o is the system output power, H 1,i is the transfer function between the charging unit and the secondary output circuit.

[0031] As a preferred solution of the multi-pickup single capacitor coupling UAV wireless charging system under the three-dimensional electric field of the present invention, the transfer function between the charging unit and the secondary output circuit is shown as follows:

[0032]

[0033] Among them, U1 is the input voltage of the transmitting end of the coupling electric field, U2, U3, and U4 are the terminal voltages of the receiving end, and C mi , C ai , C bi , C ci , i=1, 2, 3 are the equivalent Π model capacitance parameters of the secondary output circuit respectively.

[0034] As a preferred solution of the multi-pickup single capacitor coupling UAV wireless charging system under the three-dimensional electric field of the present invention, wherein: the self-capacitance of the electrode plate is determined according to the geometric size and shape;

[0035] When the size of the electrode plate is significantly smaller than the distance between the electrode plate and the ground, a capacitance to ground is formed between the electrode plate and the ground; the capacitance to ground is half of the self-capacitance of the electrode plate, and the self-capacitance of the electrode plate and the majority capacitance to ground are determined by the following formula:

[0036]

[0037] Where c is the circumference of the plate, S is the area of ​​the plate, C z is the plate self-capacitance, C ii is the capacitance to ground.

[0038] As a preferred solution of the multi-pickup single capacitor coupling UAV wireless charging system under the three-dimensional electric field of the present invention, the capacitance between the electrode plate and the corresponding parallel electrode plate is determined by the following formula:

[0039] C s =ε0·ε r ·S / d

[0040] Among them, ε0 and ε r are the dielectric constants of the plates and the dielectric constant of air respectively, S is the area facing the plates, and d is the distance between the plates.

[0041] As a preferred solution of the multi-pickup single capacitor coupling UAV wireless charging system under the three-dimensional electric field of the present invention, wherein: the plate of the transmitting end is different from the plate of the receiving end in size, and the plate size of the transmitting end is larger than the plate size of the receiving end.

[0042] The beneficial effect of the present invention is that the ECPT system has a larger coupling area between the plates, which reduces the voltage and impact resistance requirements of the semiconductor devices in the circuit, saving costs to a certain extent. At the same time, the design of the multi-dimensional electric field makes the installation position of the receiving plate on the drone unrestricted, and only needs to maintain a certain interval. The present invention further improves the transmission performance of the system by using a multi-channel transmission method. Compared with the offset simulation data of the single-pickup ECPT system, the multi-pickup ECPT system proposed by the present invention has higher transmission power and transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0044] Figure 1 This is the structural block diagram of the multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field.

[0045] Figure 2 Circuit diagram of the multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field.

[0046] Figure 3 This is a full capacitor model diagram of the quadrupole coupling mechanism consisting of the transmitting and receiving plates of the multi-pickup single capacitor coupling drone wireless charging system under a three-dimensional electric field.

[0047] Figure 4 This is the equivalent model diagram of the stray capacitance to the ground of the multi-pickup single capacitor coupled CPT system of the multi-pickup single capacitor coupled UAV wireless charging system under three-dimensional electric field.

[0048] Figure 5 This is the equivalent controlled source model diagram of the N2 network of the multi-pickup single capacitor coupled UAV wireless charging system under three-dimensional electric field.

[0049] Figure 6 This is the fundamental wave approximate circuit diagram of the N2 network of the multi-pickup single capacitor coupling drone wireless charging system under three-dimensional electric field.

[0050] Figure 7 The distribution diagram of the electric field intensity between plates in the system simulation of a multi-pickup single capacitor coupled UAV wireless charging system under a three-dimensional electric field.

[0051] Figure 8 The inverter output voltage and circuit waveform of the parallel multi-pickup single capacitor coupling system of the multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field.

[0052] Fig. 9 This is the voltage and circuit waveform diagram of the single-ended reception on the secondary side of the parallel multi-pickup single capacitor coupling system of the multi-pickup single capacitor coupling UAV wireless charging system under a three-dimensional electric field.

[0053] Fig.10 This is the system output voltage and circuit waveform diagram of the parallel multi-pickup single capacitor coupling system of the multi-pickup single capacitor coupling UAV wireless charging system under a three-dimensional electric field.

[0054] Fig.11 The inverter output voltage and circuit waveform of the traditional single capacitor coupling system of the multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field.

[0055] Fig.12 The voltage and circuit waveforms received by the secondary side of the traditional single-capacitor coupling system of the multi-pickup single-capacitor coupling UAV wireless charging system under a three-dimensional electric field.

[0056] Fig.13 The system output voltage and circuit waveform diagram of the traditional single capacitor coupling system simulation waveform of the multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field. DETAILED DESCRIPTION

[0057] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0058] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0059] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0060] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0061] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0062] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] Example 1

[0064] The first embodiment of the present invention provides a multi-pickup single capacitor coupling UAV wireless charging system under a three-dimensional electric field, comprising:

[0065] A charging unit, comprising a DC power supply, an inverter connected to an output end of the DC power supply, and a primary resonance compensation circuit connected to an output end of the inverter;

[0066] A coupling electric field is connected to the output end of the primary resonance compensation circuit, and the coupling electric field includes a transmitting end and multiple groups of receiving ends;

[0067] A drone unit is connected to the charging unit through the coupling electric field; the drone unit includes a plurality of secondary output circuits, and a battery component connected to the output end of the secondary output circuit; the secondary output circuit includes a secondary resonance compensation circuit and a secondary rectifier connected to the output end of the secondary resonance compensation circuit;

[0068] The receiving end is electrically connected to the primary resonance compensation circuit, and the receiving end is electrically connected to multiple groups of secondary resonance compensation circuits respectively.

[0069] For example, in one feasible embodiment, as follows:

[0070] The primary side resonant compensation circuit and the three-way secondary side resonant compensation circuit are symmetrically arranged LC resonant topology structures. The primary side resonant compensation circuit includes a primary side compensation inductor L p And the primary compensation capacitor C p The first secondary resonant compensation circuit includes a secondary compensation inductor L s1 And the secondary compensation capacitor C s1 The second secondary resonant compensation circuit includes a secondary compensation inductor L s2 And the secondary compensation capacitor C s2 The third secondary resonant compensation circuit includes a secondary compensation inductor L s3 And the secondary compensation capacitor C s3 . Figure 2 Among them, N1 is the primary power grid and inverter topology network, N2 is the primary and secondary resonant network and coupling mechanism, N3 is the secondary rectifier topology and load, P1 is the plate of the transmitting end, P2 is the plate of the first receiving end, P3 is the plate of the second receiving end, and P4 is the plate of the third receiving end.

[0071] For example, in one feasible embodiment, as follows:

[0072] like Figure 3 As shown, the coupling electric field includes three capacitive couplers. The three capacitive couplers share the same transmitting end plate, which is equivalent to input parallel connection. There is a coupling capacitor C between each coupler. 12 , C 13 and C 14 ; Mutual capacitance C23 , C 24 , C 34 ; Capacitance to ground C 11 , C 22 , C 33 , C 44 .

[0073] Without considering the edge effect of the plates, the capacitance between the parallel plates can be calculated by the following formula:

[0074] C s =ε0·ε r ·S / d

[0075] Among them, ε0 and ε r are the dielectric constants of the plates and the dielectric constant of air, respectively, S is the area facing the plates, and d is the distance between the plates;

[0076] At the same time, when the size of the plate is much smaller than the distance between the plate and the ground, four ground capacitances C can be formed between the four plates and the infinite distance (which can also be regarded as the ground). 11 , C 22 , C 33 and C 44 , its capacitance to ground is equal to half of the plate's self-capacitance. The size of the self-capacitance is determined only by its geometric size and shape. Its self-capacitance C z And the capacitance to ground C ii It can be calculated by the following formula:

[0077]

[0078] Among them, c is the circumference of the plate and S is the area of ​​the plate.

[0079] In this embodiment, the three receiving plates are far apart, and their mutual cross capacitance is usually several orders of magnitude different from the coupling capacitance, so the mutual capacitance C between the plates 23 , C 24 , C 34 can be ignored. Correspondingly, Figure 4 As shown, if the stray capacitance to ground is used to analyze the coupling mechanism of this system, the capacitance to ground of the charging unit, the capacitance to ground of the first secondary side, the second secondary side and the third secondary side must also be added. ex1 , C ex2 , C ex3 , C ex4 .

[0080] The derivation process of the mathematical model and equivalent circuit of the quadrupole coupling mechanism can be similarly deduced to the controlled source model corresponding to the single capacitor ECPT system. Figure 2 The controlled source model of the N2 network is as follows: Figure 5 shown.

[0081] Furthermore, in this embodiment, it is difficult to unify the parameters of the three receiving ends. The flexible receiving end design of the present application supports adjusting the final output of each end by changing the value of the reactive components of the secondary side resonant network, so that each port is voltage-balanced to achieve the best output effect. Figure 5 The expressions of X1, X2, X3, and X4 are as follows:

[0082]

[0083] Ignoring higher harmonics and not considering the loss of switching devices, the controlled voltage source substitution method is used to decouple the primary and secondary coupled circuits and simplify them into: Figure 6 The fundamental wave approximate circuit model shown is used to realize the conversion from the stray capacitance coupling model to the Π model using the following formula.

[0084]

[0085] Among them, C 11 is the capacitance of the transmitting plate to ground, C ex1 is the capacitance of the charging unit to ground, C 12 is the capacitance between the plate at the transmitting end and the plate at the first receiving end, C 22 is the capacitance of the plate of the first receiving end to ground, C ex2 is the capacitance to ground of the first secondary output circuit, C 33 is the capacitance of the plate of the second receiving end to ground, C ex3 is the capacitance to ground of the second secondary output circuit, C 13 is the capacitance between the plate at the transmitting end and the plate at the second receiving end, C 44 is the capacitance of the plate of the third receiving end to ground, C ex4 is the capacitance to ground of the third secondary output circuit, C 14 is the capacitance between the plate at the transmitting end and the plate at the third receiving end. Figure 6 middle, C A =(C a1 +C a2 +C a3 )-(C c1 +C c2 +C c3 ).

[0086] In the multi-pickup ECPT system, the double-sided LC topology can be used to achieve a constant current output at the output port that is not affected by the load. Its coupling plate, as a single capacitor, also participates in the LC resonance of the primary and secondary sides, so the equivalent input capacitance C of the coupling equivalent model port is first defined. in,pri , C in,sec1 , C in,sec2 and Cin,sec3 for:

[0087]

[0088] Among them, C in,pri , C in,sec1 , C in,sec2 and C in,sec3 is the equivalent input capacitance of the coupling equivalent model, I1 is the output current of the charging unit, U1 is the output voltage of the charging unit, I2 is the output current of the first secondary output circuit, U2 is the output voltage of the first secondary output circuit, I3 is the output current of the second secondary output circuit, U3 is the output voltage of the second secondary output circuit, I4 is the output current of the third secondary output circuit, U4 is the output voltage of the third secondary output circuit, C a1 , C a2 , C a3 , C b1 , C b2 , C b3 , C c1 , C c2 , C c3 is the capacitance after conversion from stray capacitance coupling model to Π model.

[0089] Then the parameter design of the system passive resonant element meets the resonance condition:

[0090]

[0091] Among them, L p and C p They are the primary compensation inductor and primary compensation capacitor, L s1 and C s1 are the first secondary compensation inductor and the secondary compensation capacitor, L s2 and C s1 are the second secondary compensation inductor and the secondary compensation capacitor, L s3 and C s3 They are the third secondary side compensation inductor and secondary side compensation capacitor respectively.

[0092] When the system meets the resonance condition, the system output current and output power are:

[0093]

[0094] Among them, U in is the inverter output voltage, U out is the system output voltage, I o is the system output current, P o is the system output power, H 1,i is the transfer function between the primary side and the three secondary sides:

[0095]

[0096] In summary, the present invention enables the ECPT system to have a larger coupling area between the plates, reduces the voltage and impact resistance requirements of the semiconductor devices in the circuit, and saves costs to a certain extent. At the same time, the design of the multi-dimensional electric field makes the installation position of the receiving plate on the drone unrestricted, and only needs to maintain a certain interval. The present invention further improves the transmission performance of the system by using a multi-channel transmission method. Compared with the offset simulation data of the single-pickup ECPT system, the multi-pickup ECPT system proposed in the present invention has higher transmission power and transmission efficiency.

[0097] Example 2

[0098] This is the second embodiment of the present invention. This embodiment provides a multi-pickup single capacitor coupling UAV wireless charging system under a three-dimensional electric field. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0099] Based on the COMSOL simulation platform, metal aluminum is simulated as the material of the electrode plate of the transmitting end, the electrode plate of the first receiving end, the electrode plate of the second receiving end and the electrode plate of the third receiving end, and no dielectric layer is set.

[0100] The plates of the first receiving end, the second receiving end and the third receiving end are respectively oriented in the positive direction of the x, y and z axes and are parallel to the three faces of the transmitting plate. They are loaded on the tripod or fuselage of the drone at a certain distance. They are long strips of aluminum plates. The bottom plate and each face of the two side plates of the transmitting end plate are 400mm×400mm in size and 2mm in thickness; the plates of the first receiving end, the second receiving end and the third receiving end are all 20mm×100mm long strips of aluminum plates with a thickness of 2mm; the spacing between the primary and secondary plates is 0.1mm; in order to reduce the mutual capacitance between different couplers, the three receiving end plates are set relatively far apart.

[0101] Simulation results analysis:

[0102] Coupled self-capacitance and coupled mutual capacitance: Add excitation voltage to the plates to simulate the system operation. The electric field strength / charge density distribution is as follows: Figure 7 By setting the terminal potential of the four plates and performing a parametric sweep study, the Maxwell capacitance matrix calculation results can be obtained as shown in Table 1, where C 11 , C 22 , C 33 , C 44All are estimated to be half of the self-capacitance of the three plates. Table 1 defines that the plate at the first receiving end and the plate at the transmitting end form a lower coupler, the plate at the second receiving end and the plate at the transmitting end form a side coupler, and the plate at the third receiving end and the plate at the transmitting end form a rear coupler. Figure 7 middle: Figure 7 (a) is the distribution diagram of the electric field intensity between the plates in the positive direction of the Z axis. Figure 7 (b) is the distribution diagram of the electric field intensity between the plates in the positive direction of the X axis. Figure 7 (c) is the distribution diagram of the electric field intensity between the plates in the positive direction of the Y axis.

[0103] Table 1 Cross-coupling capacitor simulation results

[0104]

[0105] Parameter design:

[0106] Use Figure 2 For the resonant topology shown in the figure, when the coupling mechanism offset is not large, the coupling capacitance related to the coupling mechanism is also determined accordingly, and the coupling topology simulation parameters are shown in Table 2. The corresponding C in,pri , C in,sec1 , C in,sec2 , C in,sec3 The value of can also be calculated, and further the L of the common LC resonant network can be determined p and L s (L s1 , L s2 and L s3 ) value; the load-end filter capacitor C0 can be taken as μF level.

[0107] Table 2 Multi-pickup CPT system coupling topology simulation parameters

[0108]

[0109]

[0110] Transmission performance analysis: Under the same coupling parameters, the equivalent models of the multi-pickup single capacitor coupled ECPT system proposed in this application and the traditional single pickup system are simulated through the Simulink platform, and the inverter output, rectifier output waveform and output power of the multi-pickup single capacitor coupled ECPT system proposed in this application are obtained as follows: Figure 8 , Fig. 9 and Fig.10 As shown, the inverter output, rectifier output waveform and output power of the equivalent model of the traditional single pickup system are as follows: Fig.11 , Fig.12 and Fig.13 shown.

[0111] From the analysis of the above figure, it can be seen that the multi-pickup single capacitor coupled ECPT system of the present application has a faster response time and a smaller system tracking error. The voltage waveform output by the rectifier circuit is relatively stable, and there is no large fluctuation; under the same simulation parameters, compared with the above two different circuit structures, the output power of the single capacitor coupled multi-pickup ECPT system described in the present application is higher than that of the traditional single-channel ECPT system, and the power improvement percentage is close to 209%, which is about 3 times that of single-channel transmission. The new multi-channel UAV charging system proposed by the present invention has good output stability and high charging power.

[0112] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field, Features: include, A charging unit, comprising a DC power supply, an inverter connected to an output end of the DC power supply, and a primary resonance compensation circuit connected to an output end of the inverter; A coupling electric field connected to the output end of the primary resonance compensation circuit, wherein the coupling electric field includes a transmitting end and multiple groups of receiving ends; A drone unit is connected to the charging unit through the coupling electric field; the drone unit includes a plurality of secondary output circuits, and a battery component connected to the output end of the secondary output circuit; the secondary output circuit includes a secondary resonance compensation circuit and a secondary rectifier connected to the output end of the secondary resonance compensation circuit; Wherein, the receiving end is electrically connected to the primary resonance compensation circuit, and the receiving end is electrically connected to multiple groups of secondary resonance compensation circuits respectively.

2. The multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field as claimed in claim 1, Features: The primary side resonance compensation circuit and the secondary side resonance compensation circuit are symmetrically arranged LC resonance topology structures; The primary resonance compensation circuit includes a primary compensation inductor and a primary compensation capacitor; the secondary resonance compensation circuit includes a secondary compensation inductor and a secondary compensation capacitor.

3. The multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field as claimed in claim 2, Features: The coupling electric field includes a plurality of capacitive couplers, and the plurality of capacitive couplers share the same transmitting end; The capacitive coupler includes a coupling capacitor, a mutual capacitor and a ground capacitor; The coupling electric field controls the output port to output a constant current that is not affected by the load through a coupling equivalent model; The equivalent input capacitance of the coupling equivalent model is determined as follows: Among them, C in,pri , C in,sec1 , C in,sec2 and C in,sec3 is the equivalent input capacitance of the coupling equivalent model, I 1 is the output current of the charging unit, U 1 is the output voltage of the charging unit, I 2 is the output current of the first secondary output circuit, U 2 is the output voltage of the first secondary output circuit, I 3 is the output current of the second secondary output circuit, U 3 is the output voltage of the second secondary output circuit, I 4 is the output current of the third secondary output circuit, U 4 is the output voltage of the third secondary output circuit, C a1 , C a2 , C a3 , C b1 , C b2 , C b3 , C c1 , C c2 , C c3 is the capacitance after conversion from stray capacitance coupling model to Π model.

4. The multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field as claimed in claim 3, Features: The capacitance after conversion from the stray capacitance coupling model to the Π model is determined by the following formula: Among them, C 11 is the capacitance of the transmitting plate to ground, C ex1 is the capacitance of the charging unit to ground, C 12 is the capacitance between the plate at the transmitting end and the plate at the first receiving end, C 22 is the capacitance of the plate of the first receiving end to ground, C ex2 is the capacitance to ground of the first secondary output circuit, C 33 is the capacitance of the plate of the second receiving end to ground, C ex3 is the capacitance to ground of the second secondary output circuit, C 13 is the capacitance between the plate at the transmitting end and the plate at the second receiving end, C 44 is the capacitance of the plate of the third receiving end to ground, C ex4 is the capacitance to ground of the third secondary output circuit, C 14 is the capacitance between the plate at the transmitting end and the plate at the third receiving end.

5. The multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field as claimed in claim 4, Features: The coupling electric field adjusts the passive resonant element through a coupling equivalent model to make the charging system reach a resonant state; The adjustment of the passive resonant element is shown in the following equation: Among them, L p and C p They are the primary compensation inductor and primary compensation capacitor, L s1 and C s1 are the first secondary compensation inductor and the secondary compensation capacitor, L s2 and C s1 are the second secondary compensation inductor and the secondary compensation capacitor, L s3 and C s3 They are the third secondary side compensation inductor and secondary side compensation capacitor respectively.

6. The multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field as claimed in claim 4, Features: When the charging system reaches a resonant state, the output current and output power of the charging system are as follows: Among them, U in is the inverter output voltage, U out is the system output voltage, I o is the system output current, P o is the system output power, H 1,i is the transfer function between the charging unit and the secondary output circuit.

7. The multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field as claimed in claim 6, Features: The transfer function between the charging unit and the secondary output circuit is shown in the following formula: Among them, U 1 is the input voltage at the transmitting end of the coupled electric field, U 2 , U 3 , U 4 are the terminal voltage at the receiving end, C mi , C ai , C bi , C ci , i=1, 2, 3 are the equivalent Π model capacitance parameters of the secondary output circuit respectively.

8. The multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field as claimed in claim 4, Features: The self-capacitance of the plate is determined by the geometric size and shape; A capacitance to ground is formed between the plate and the ground; the capacitance to ground is half of the self-capacitance of the plate. The self-capacitance of the plate and the majority capacitance to ground are determined by the following formula: Where c is the circumference of the plate, S is the area of ​​the plate, C z is the plate self-capacitance, C ii is the capacitance to ground.

9. The multi-pickup single capacitor coupling UAV wireless charging system under three-dimensional electric field as claimed in claim 8, Features: The capacitance between the plate and the corresponding parallel plate is determined by the following formula: C s =e 0 ·e r ·S / d Among them, ε 0 and ε r are the dielectric constants of the plates and the dielectric constant of air respectively, S is the area facing the plates, and d is the distance between the plates.

10. The multi-pickup single capacitor coupling wireless charging system for drones under a three-dimensional electric field as claimed in claim 9, Features: The size of the electrode plate at the transmitting end is different from that of the electrode plate at the receiving end, and the size of the electrode plate at the transmitting end is larger than that of the electrode plate at the receiving end.

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