High-offset-resistance wireless charging system compatible with multi-size unmanned aerial vehicles

Abstract

The invention relates to the technical field of wireless power transmission, in particular to a high anti-offset wireless charging system compatible with multi-size unmanned aerial vehicles, which comprises a transmitting end mounted on a parking apron, and the transmitting end is composed of a first annular transmitting coil and a second annular transmitting coil which are reversely connected in series and have the same central point, a gap exists between the first annular transmitting coil and the second annular transmitting coil; the first receiving end and the second receiving end are respectively mounted on horizontal cross rods of two foot stools of the target unmanned aerial vehicle; when the target unmanned aerial vehicle lands on the parking apron, the first receiving end and the second receiving end can capture horizontal magnetic flux generated by the first annular transmitting coil and the second annular transmitting coil, and the target unmanned aerial vehicle is charged. According to the invention, the double receiving ends have the same mutual inductance and output power even if the distances are different, so that the method is suitable for the receiving ends with different spacing sizes; and when small-range deviation occurs, the total mutual inductance fluctuates within an allowable range, so that efficient transmission of electric energy is ensured.

Description

Technical Field

[0001] The present invention relates to a high anti-offset wireless charging system compatible with multi-size drones, belonging to the technical field of wireless power transmission. Background Art

[0002] Due to its simple operation and low price, drones play an important role in fields such as remote sensing monitoring, emergency rescue and disaster relief, safety inspection, and logistics transportation. During the continuous development and improvement of performance and power, the insufficient endurance of drones has always been one of the important factors affecting their flight performance such as load capacity and continuous operation. Currently, the solution of building a drone charging station in the flight route is adopted, and the wireless power transmission technology is used to autonomously charge during the stop and loading / unloading process, without the need for manual plugging and unplugging of the wired power plug. While equipped with a small-volume battery and other energy storage devices, it has a large working range, fundamentally solving the problem of insufficient endurance.

[0003] However, drones using wireless power supply technology still face many problems. For example, the shape, volume, and load-bearing capacity of the drone's landing gear have a great impact on the coil design and installation position selection of the receiving end. Currently, there are consumer-grade and industrial-grade drones in the market, and there is no unified standard for the size width of the landing gear and the load-bearing capacity of the fuselage of different types of drones. To adapt to different types of drones, it is necessary to design special coupling mechanisms and landing pads for them, which seriously affects the efficiency and cost of wireless charging; due to the error of the positioning system or the influence of environmental weather, there is a landing point error when the drone lands on the charging platform, and the misalignment of the center points of the primary and secondary sides of the wireless charging coupling mechanism leads to a decrease in the coupling coefficient and a decrease in the transmission power, or even an inability to charge stably. Summary of the Invention

[0004] In order to solve the technical problems in the prior art that the existing wireless charging coupling mechanism cannot adapt to different types of drones and the misalignment of the center points when the drone falls leads to a decrease in the power transmission of electric energy, the present invention further provides a high anti-offset wireless charging system compatible with multi-size drones.

[0005] The technical solution adopted by the present invention to solve the above problems is: The present invention includes a high anti-offset wireless charging system compatible with multi-size drones, including:

[0006] A transmitting end installed on the landing pad, where the transmitting end consists of a first annular transmitting coil and a second annular transmitting coil with the same center point connected in reverse series, and there is a spacing between the first annular transmitting coil and the second annular transmitting coil;

[0007] It further includes a first receiving end and a second receiving end respectively installed on the horizontal crossbars of the two landing gears of the target drone;

[0008] When the target UAV lands on the landing pad, the first receiving end and the second receiving end can capture the horizontal magnetic flux generated by the first annular transmitting coil and the second annular transmitting coil to charge the target UAV.

[0009] In some embodiments, both the first receiving end and the second receiving end are composed of a rectangular ferrite and a receiving coil vertically wound around the rectangular ferrite.

[0010] In some embodiments, the ring diameter of the first annular coil is r p1 , the ring diameter of the second annular coil is r p2 , the spacing distance between the first annular coil and the second annular coil is a, and the inner radius of the second annular coil is b, where r p1 = r p2 = a = 2b.

[0011] In some embodiments, the distance between the first receiving end and the second receiving end respectively installed on the horizontal crossbars of the two legs of the target UAV is d1 = 2r p1 + 2r p2 + 2a + 2b.

[0012] In some embodiments, the distance between the first receiving end and the second receiving end respectively installed on the horizontal crossbars of the two legs of the target UAV is d2 = 2r p2 + 2a + 2b.

[0013] In some embodiments, the distance between the first receiving end and the second receiving end respectively installed on the horizontal crossbars of the two legs of the target UAV is d3 = 2r p2 + 2b.

[0014] In some embodiments, the distance between the first receiving end and the second receiving end respectively installed on the horizontal crossbars of the two legs of the target UAV is d4 = 2b.

[0015] The beneficial effects of the present invention are as follows:

[0016] 1. The wireless charging system of the present invention uses a reverse series structure of dual annular transmitting coils to transfer energy to the dual receiving ends (installed on the horizontal crossbars of the UAV legs) by using horizontal magnetic flux. Even if the distances between the dual receiving ends are different, they have the same mutual inductance and output power, meeting the requirement that a single transmitting structure can adapt to multiple receiving ends of different sizes; when the centers of the transmitting end and the receiving end are offset, the total magnetic flux captured by the dual receiving ends is approximately a straight line after superposition, ensuring that the total mutual inductance fluctuation is within the allowable range during a small range of offset, enabling the wireless charging system of the present invention to adapt to different types of UAVs while ensuring efficient power transmission.

[0017] 2. The wireless charging system of the present invention can also adjust the parameters of the transmitting coil to change the trend of mutual inductance change, meet the wireless charging and allowable offset range requirements of different models of unmanned aerial vehicles, and further improve the applicable range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0019] Figure 1 It is a schematic structural diagram of a high anti-offset wireless charging system compatible with multi-size unmanned aerial vehicles provided by this application;

[0020] Figure 2 It is a schematic diagram when the unmanned aerial vehicle provided by this application lands on the apron;

[0021] Figure 3 It is a schematic diagram of the size of the transmitting end provided by this application;

[0022] Figure 4 It is a circuit schematic diagram of the coupling mechanism of the wireless charging system provided by this application;

[0023] Figure 5 It is a schematic diagram of the size of the coupling mechanism of the wireless charging system in the specific embodiment provided by this application;

[0024] Figure 6 It is a schematic diagram of the mutual inductance curve M obtained by simulation with a single receiving end provided by this application PS1 ;

[0025] Figure 7 It is a schematic diagram of four situations under multi-size compatibility provided by this application;

[0026] Figure 8 It is a schematic diagram of the mutual inductance change curve of the dual receiving end provided by this application;

[0027] Figure 9 It is a schematic diagram of the output voltage and current waveforms of the circuit simulation at four distances provided by this application;

[0028] Figure 10 It is a schematic diagram of the simulation of the situation with an offset of ±100 mm provided by this application;

[0029] Figure 11 It is a waveform diagram of the output voltage and current when the simulation offset is ±100 mm provided by this application. DETAILED DESCRIPTION OF THE EMBODIMENTS Specific Embodiment 1:

[0031] Combined with Figure 1 To illustrate this embodiment, this embodiment provides a high anti-offset wireless charging system compatible with multi-size drones, including:

[0032] A transmitting end installed on the landing pad, where the transmitting end consists of a first circular transmitting coil and a second circular transmitting coil with the same center point connected in reverse series, and there is a spacing between the first circular transmitting coil and the second circular transmitting coil;

[0033] It also includes a first receiving end and a second receiving end respectively installed on the horizontal crossbars of the two legs of the target drone;

[0034] Among them, when the target drone lands on the landing pad, the first receiving end and the second receiving end can capture the horizontal magnetic flux generated by the first circular transmitting coil and the second circular transmitting coil to charge the target drone.

[0035] As Figure 2 shown, it is a schematic diagram when the drone lands on the landing pad. As can be seen from Figure 2 it, the first receiving end and the second receiving end are respectively installed on the horizontal crossbars of the two legs of the target drone.

[0036] It should be noted that two reversely wound circular coils (the first circular transmitting coil and the second circular transmitting coil) are placed in series above the circular ferrite.

[0037] In the wireless charging system coupling mechanism, the two receiving ends on the left and right sides are respectively denoted as the first receiving end R X1 、the second receiving end R X2 , the self-inductances of the two receiving ends are respectively L S1 、L S2 ; the first circular transmitting coil and the second circular transmitting coil in the transmitting coil are respectively denoted as T X1 、T X2 , the self-inductances of the two transmitting coils are L P1 、L P2 . The mutual inductances between L S1 、L S2 and L P1 are denoted as M P1S1 、M P1S2 , the mutual inductances between L S1 、L S2 and L P2 are denoted as M P2S1 、M P2S2 , if considering the two transmitting coils connected in reverse series and regarded as one transmitting coil, there is a combined mutual inductance M PS1 = M P1S1 + MP2S1 , M PS2 = M P1S2 + M P2S2 , used to obtain the mutual inductance change trend when the relative distance between the single receiving end and the center point changes, so as to determine the distance between the receiving ends on the left and right sides. The mutual inductance finally obtained by the two receiving ends can be synthesized into M eq = M PS1 + M PS2 , used to obtain the mutual inductance change trend during offset and judge whether the mutual inductance volatility meets the allowable range.

[0038] It should be noted that due to the complementary effect of the magnetic flux change of the dual receiving ends, that is, when the magnetic flux captured by one receiving end increases, the magnetic flux of the other receiving end decreases, and the total magnetic flux is approximately constant. Therefore, when there is a small range of offset between the transmitting end and the receiving end, the total mutual inductance of the wireless charging system remains basically unchanged, resulting in a small power fluctuation of the wireless energy transmission and improving the power supply stability.

[0039] In the specific application of the wireless charging system, based on the distance between the two receiving ends on the two legs of different models of drones, the power transmission requirements of the wireless charging system, the allowable offset range and the power volatility requirements, the size, number of turns and geometric parameters of the transmitting coil can be optimized to ensure that different models of drones can achieve efficient and stable wireless charging and meet the requirements of shared drone wireless power supply.

[0040] In some embodiments, both the first receiving end and the second receiving end are composed of a rectangular ferrite and a receiving coil vertically wound around the rectangular ferrite.

[0041] In some embodiments, the ring diameter of the first toroidal coil is r p1 , the ring diameter of the second toroidal coil is r p2 , the distance between the first toroidal coil and the second toroidal coil is a, and the inner radius of the second toroidal coil is b, where r p1 = r p2 = a = 2b.

[0042] In some embodiments, the distance between the first receiving end and the second receiving end respectively installed on the horizontal crossbars of the two legs of the target drone is d1 = 2r p1 + 2r p2 + 2a + 2b.

[0043] In some embodiments, the distance between the first receiving end and the second receiving end respectively installed on the horizontal crossbars of the two legs of the target drone is d2 = 2r p2 + 2a + 2b.

[0044] In some embodiments, the distance between the first receiving end and the second receiving end respectively installed on the horizontal crossbars of the two legs of the target unmanned aerial vehicle is d3 = 2r p2 + 2b.

[0045] In some embodiments, the distance between the first receiving end and the second receiving end respectively installed on the horizontal crossbars of the two legs of the target unmanned aerial vehicle is d4 = 2b.

[0046] It should be noted that for the purpose of solving the technical problems in the prior art that the existing wireless charging coupling mechanism cannot adapt to different types of unmanned aerial vehicles and the power transmission power decreases due to the misalignment of the center point when the unmanned aerial vehicle falls, the design steps of the coupling mechanism of the wireless charging system in the present invention are as follows:

[0047] (1) Give the basic parameters of the coupling mechanism, such as system power, frequency, current and voltage of the transmitting end, current and voltage of the receiving end, working distance between the transmitting end and the receiving end, size of the receiving end (distance between the two receiving ends), etc., and determine the shape of the coupling mechanism;

[0048] (2) Select appropriate wires for the transmitting and receiving coils. The wire diameters of the inner and outer coils of the transmitting coil can be different. Ensure that the voltage and current stresses are met, and set the number of turns N of the outer coil of the transmitting coil Lp1 , the number of turns N of the inner coil Lp2 ;

[0049] (3) According to the maximum distance d between the receiving end and the center point S_1 Determine the outer size R of the transmitting end P , the ring diameter of the outer ring coil is r p1 , the ring diameter of the inner ring coil is r p2 , the distance between the inner and outer circles is a, the inner diameter of the inner circle is b, initially let d S_1 = R P , r p1 = r p2 = a = 2b, as Figure 3 shown, is the schematic diagram of the transmitting end size;

[0050] (4) Establish a finite element simulation model. By adjusting appropriate N Lp1 , N Lp2 , make the horizontal magnetic flux generated by the transmitting end approximately a sine wave;

[0051] (5) After determining the parameters of the transmitting end, taking the maximum size of the receiving end as an example, adjust the number of turns N of the receiving coil Ls and the ferrite size to meet the mutual inductance required by the system and the model of the unmanned aerial vehicle;

[0052] (6) Taking the coupling system in (5) as a reference, find other sizes with equal mutual inductance. In this design, there are 4 distances from the center point, which are d S_1, d S_2 , d S_3 , d S_4 , the different distances between the two receivers can be combined as d1 = 2 * d S_1 = 2r p1 + 2r p2 + 2a + 2b, d2 = 2 * d S_2 = 2r p2 + 2a + 2b, d3 = 2 * d S_3 = 2r p2 + 2b, d4 = 2 * d S_4 = 2b, which is verified by simulation;

[0053] (7) Taking the maximum size of the receiver as an example, the mutual inductance curves of the left and right receivers are synthesized into a total mutual inductance curve, and the change trend of the offset mutual inductance is observed to see if the mutual inductance volatility is within the allowable range. If it cannot be satisfied, adjust the outer size of the transmitter and start the design from (4); if it is satisfied, it is considered that the design of the coupling mechanism is completed.

[0054] Further, as Figure 4 shown, it is the circuit schematic diagram of the coupling mechanism of the wireless charging system in the present invention.

[0055] From Figure 4 it can be seen that the overall system adopts the LCC - S topology. The adjustable DC power supply is used as the electrical energy input device, which connects to the AC power at the required working frequency output by the high - frequency inverter. After passing through the primary and secondary compensation networks, a square - wave voltage is output. The square - wave is rectified and filtered to obtain a stable DC power supply to supply the load. Utilizing the characteristics of constant current at the transmitter and constant voltage at the receiver of the LCC - S topology, it ensures that the output power is constant with unchanged mutual inductance. At the same time, the DC voltages after rectification of the two receivers can be connected in series to ensure that when the signs of M PS1 and M PS2 are different, it will not affect the output voltage U O , reducing the power fluctuation. Specific Embodiment 2:

[0057] To facilitate the understanding of the technical solution of Embodiment 1, this application is illustrated by specific examples.

[0058] The basic parameters of the wireless charging system designed in this specific embodiment are shown in Table 1. It is determined that the shape of the transmitter is circular, and the receiver is a solenoid coil vertically wound on a ferrite. The parameters of the coupling mechanism are shown in Table 2. The schematic diagram of the size of the coupling mechanism of the wireless charging system in the specific embodiment is as Figure 5 shown, and a finite - element simulation model is established to simulate and verify the change trend of the mutual inductance of the coupling mechanism and the offset volatility.

[0059] Parameter Value Rated power 500W Frequency 85 kHz Operating distance 5 mm Input current 15A Output voltage 50V

[0060] Table 1

[0061] Parameter Value NLp1 13 NLp2 16 RP 245 mm rp1 70 mm rp2 70 mm a 70 mm b 35 mm dS_1 245 mm

[0062] Table 2

[0063] As Figure 6 shown, it is a schematic diagram of the mutual inductance curve M obtained by single-receiver simulation. Among them, M PS1 that meets the system parameter design is 3 μH, corresponding to the distances between the receiver and the center point of 30 mm, 100 mm, 170 mm, and 240 mm. The total sizes of the double receivers are 60 mm, 200 mm, 340 mm, and 480 mm respectively. The schematic diagrams of 4 cases under the allowable multi-size compatibility are as PS1 shown. The schematic diagram of the mutual inductance change curve of the double receivers is as Figure 7 shown. The volatility within the allowable range of ±100 mm is 7.6%. Figure 8

[0064] The design of this specific embodiment is verified through circuit simulation. The key parameters and their symbols are shown in Table 3.

[0065] Parameter Symbol DC power supply UDC Inverting MOS S1 - S4 Parallel resonance inductor L1 Parallel resonance capacitor C1 Series resonance capacitor C2 Emitter self - inductance Lp1, Lp2 Receiver self - inductance Ls1, Ls1 Series resonance capacitor Cs1, Cs1 Emitter coil current IP Total output voltage UO Total output current IO

[0066] Table 3

[0067] The schematic diagrams of the output voltage and current waveforms of the circuit simulation under four distances are as Figure 9 shown. It can be seen that the output voltages and powers of the single receiver under the four distances are approximately equal. Based on this, the 4 sizes obtained can meet the requirements of multi-size compatibility.

[0068] Figure 7 Furthermore, taking the second distance of 200 mm in Figure 7 as an example, the schematic diagram of the simulation offset of ±100 mm is as Figure 10 shown. The output fluctuations within the simulation offset of ±100 mm are obtained. The waveform diagram of the output voltage and current when the simulation offset is ±100 mm is as Figure 11 shown. It can be seen that the output voltage volatility is 8.6%. Figure 10 The total output voltages of the three cases in

[0069] are approximately 46 V, 50 V, and 42 V respectively, increasing first and then decreasing, which is in line with the mutual inductance change trend of the coupling mechanism simulation. This proves the effectiveness of the coupling mechanism design method.

[0070] In summary, the present application provides a highly anti-offset wireless charging system compatible with multi-size drones, including: a transmitting end installed on a landing pad, the transmitting end being composed of a first annular transmitting coil and a second annular transmitting coil with the same center point connected in reverse series, and there is a spacing between the first annular transmitting coil and the second annular transmitting coil; it also includes a first receiving end and a second receiving end respectively installed on the horizontal crossbars of two legs of the target drone; wherein, when the target drone lands on the landing pad, the first receiving end and the second receiving end can capture the horizontal magnetic flux generated by the first annular transmitting coil and the second annular transmitting coil to charge the target drone.

[0071] The beneficial effects of the present invention are as follows:

[0072] 1. The wireless charging system of the present invention uses a reverse series structure of double annular transmitting coils to transmit energy to the double receiving ends (installed on the crossbars of the drone legs) through horizontal magnetic flux. Even if the distances between the double receiving ends are different, they have the same mutual inductance and output power, meeting the requirement that a single transmitting structure can adapt to multiple receiving ends of different sizes; when the centers of the transmitting end and the receiving end are offset, the total magnetic flux captured by the double receiving ends is approximately a straight line after superposition, ensuring that the total mutual inductance fluctuation is within the allowable range during a small range of offset, enabling the wireless charging system of the present invention to adapt to different types of drones while ensuring efficient power transmission.

[0073] 2. The wireless charging system of the present invention can also adjust the parameters of the transmitting coil to change the trend of mutual inductance change, meeting the wireless charging and allowable offset range requirements of different models of drones, and further improving the applicable range.

[0074] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments based on the technical essence of the present invention within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A highly anti-drift wireless charging system compatible with multi-size drones, characterized in that: include: A transmitting end installed on the apron, the transmitting end comprising a first annular transmitting coil and a second annular transmitting coil connected in series in reverse direction and having the same center point, and a distance between the first annular transmitting coil and the second annular transmitting coil; It also includes a first receiving end and a second receiving end respectively mounted on the horizontal crossbars of the two tripods of the target UAV; When the target UAV lands on the apron, the first receiving end and the second receiving end can capture the horizontal magnetic flux generated by the first annular transmitting coil and the second annular transmitting coil to charge the target UAV.

2. The wireless charging system according to claim 1, characterized in that: The first receiving end and the second receiving end are both composed of a rectangular ferrite and a receiving coil vertically wound around the rectangular ferrite.

3. The wireless charging system according to claim 1, characterized in that: The diameter of the first annular coil is r p1 , the diameter of the second annular coil is r p2 , the spacing distance between the first annular coil and the second annular coil is a, the inner radius of the second annular coil is b, wherein r p1 =r p2 =a=2b.

4. The wireless charging system according to claim 3, characterized in that: The distance between the first receiving end and the second receiving end respectively mounted on the horizontal crossbars of the two tripods of the target UAV is d1=2r p1 +2r p2 +2a+2b.

5. The wireless charging system according to claim 3, characterized in that: The distance between the first receiving end and the second receiving end respectively mounted on the horizontal cross bars of the two tripods of the target UAV is d2=2r p2 +2a+2b.

6. The wireless charging system according to claim 3, characterized in that: The distance between the first receiving end and the second receiving end respectively mounted on the horizontal cross bars of the two tripods of the target UAV is d3=2r p2 +2b.

7. The wireless charging system according to claim 3, characterized in that: The distance between the first receiving end and the second receiving end respectively mounted on the horizontal cross bars of the two tripods of the target UAV is d4=2b.

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