Three-dimensional space multi-transmit multi-receive wireless power transmission system and control method thereof

Abstract

The application relates to the technical field of magnetic coupling wireless power transmission, and particularly discloses a three-dimensional space multi-transmission multi-reception wireless power transmission system and a control method thereof. First, a three-dimensional space multi-transmission structure is designed. The transmission structure is composed of M transmission planes which are not parallel to each other. Each transmission plane is arranged in an array mode and has multiple identical transmission sub-coils, so that the power supply requirement of multiple secondary side coils in the three-dimensional space can be met. A logic control circuit is also designed. The logic control circuit comprises an FPGA control module, multiple control switches and multiple voltage sensors. The FPGA control module collects the voltages of all the transmission sub-coils before and after the secondary side coil is connected. Then, the voltage difference before and after the connection is calculated. According to the voltage difference, the transmission sub-coil in the high voltage state is activated by controlling the control switch, and the remaining transmission sub-coils are turned off. Therefore, the anti-deviation capability of the system is effectively improved, and the energy efficiency of the system is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic coupling wireless power transmission, and particularly relates to a three-dimensional space multi-transmission multi-reception wireless power transmission system and a control method thereof. BACKGROUND

[0002] At present, robots, as advanced intelligent machine devices in the world, are widely used in manufacturing, surveying, rescue and life fields. Developed countries are more and more active in the research and development of robot technology with the improvement of the level of science and technology. In the operation process of the robot, the frequent plugging and unplugging of charging increases the labor cost, and the endurance, as the key to long-term stable operation, is also concerned by scholars.

[0003] Wireless power transmission technology (WPT) is a new type of charging technology developed by researchers in recent years, and is also an advanced technology with future prospects and widespread attention from researchers at home and abroad. Magnetic coupling wireless power transmission (MC-WPT) technology is widely used because of its long transmission distance and large transmission power. At present, the exploration of the domestic technology mainly stays in the theoretical research and laboratory stage, and the research mainly relies on colleges and research institutes, while the foreign research on this technology is more extensive, and has been deeply applied to electric vehicles, mobile devices and other application scenarios.

[0004] The application of wireless power transmission technology to the charging and endurance of electronic products can realize the electrical isolation between the electronic products and the charging system, and simplify the cumbersome charging plug and charging wire. Wireless charging technology does not need additional wired plugging, overcomes the shortcomings of the traditional contact charging method for robots, reduces the corresponding labor cost, and further improves the automation degree of the charging process. Therefore, more and more researchers apply WPT technology to the scene of exhibiting electronic products, which has a bright application prospect.

[0005] At present, more literatures focus on the design of magnetic coupling mechanism of wireless power transmission system and the optimization of space energy transmission. Some literatures analyze the characteristics of square coil magnetic coupling mechanism, and compare it with circular coil by using control variable method. The difference between the two kinds of magnetic coupling mechanisms in transmission efficiency and anti-offset ability is not big, and there is no outstanding performance. Some scholars design a magnetic coupling mechanism matching multiple receiving coils, and give the corresponding application background and analyze the transmission efficiency. However, the transmission position of the multiple receiving coils matched by the proposed magnetic coupling mechanism is fixed, and once the receiving device moves, it will have a great impact. Some literatures design an asymmetric wireless power transmission system with large primary coil and small secondary coil, which improves the transmission power of the system, but the anti-lateral offset ability is weak. Once the secondary coil and the primary coil are not in the center alignment state, the transmission efficiency of the system will be greatly reduced. Some literatures design a three-dimensional space type magnetic coupling mechanism, which uses geometric structure to realize wireless power transmission in three-dimensional space, but the invalid energy transmission area is too large, resulting in low efficiency. SUMMARY

[0006] The present application provides a three-dimensional space multi-transmission multi-receiving wireless power transmission system and a control method thereof, which solves the technical problem of how to improve the anti-offset ability and transmission efficiency of the magnetic coupling wireless power transmission system matched with multiple receiving coils.

[0007] To solve the above technical problems, the present application provides a three-dimensional space multi-transmission multi-receiving wireless power transmission system, which comprises a primary circuit, a logic control circuit and one or more secondary circuits. The primary circuit comprises a direct current source, a high-frequency inverter, a primary resonance compensation network and a three-dimensional space multi-transmission structure connected in sequence. The secondary circuit comprises a secondary coil, a rectifier filter circuit and a load connected in sequence.

[0008] The three-dimensional space multi-transmission structure comprises M non-parallel transmission planes, each of which is arrayed with N identical transmission sub-coils, and M*N transmission sub-coils are connected in series, wherein M≥2 and N≥2. The overall shape of the transmission plane can cover at least one secondary coil.

[0009] The logic control circuit comprises an FPGA control module, M*N control switches connected in parallel with the FPGA control module, and M*N voltage sensors connected in parallel with the FPGA control module. The M*N control switches are connected in parallel with the M*N transmission sub-coils one by one.

[0010] The M*N voltage sensors are used to acquire the voltage of the M*N transmission sub-coils before and after the secondary coil is connected.

[0011] The FPGA control module is used for activating the transmitting sub-coil with high voltage level of voltage variation difference through controlling the corresponding control switch according to the voltage variation difference of each transmitting sub-coil before and after the access of the secondary side coil.

[0012] Specifically, the transmitting sub-coil L i The voltage variation difference |ΔU i of the P secondary side coils before and after the access is ω represents the working frequency of the system, I 2j represents the current of the secondary side coil L sj , M isj represents the mutual inductance between the transmitting sub-coil L i and the secondary side coil L sj , i = 1, 2, …, M*N, j = 1, 2, …, P, P ≥ 1.

[0013] Preferably, the primary side resonance compensation network adopts a series compensation capacitor with adjustable capacitance, and the FPGA control module is connected with the series compensation capacitor to adjust the capacitance of the series compensation capacitor according to the number of activated transmitting sub-coils, so as to achieve impedance matching.

[0014] Preferably, the N transmitting sub-coils of each transmitting plane are arranged in an A × A array, and A ≥ 2.

[0015] Preferably, M = 4, N = 9, and the four transmitting planes enclose four sides of a cube.

[0016] Preferably, when P ≥ 2, the P secondary side coils are opposite to one transmitting plane or different transmitting planes.

[0017] The application also provides a control method of the three-dimensional space multi-transmitting multi-receiving wireless electric energy transmission system.

[0018] S1, control all control switches to be in an open state, start the primary side circuit, and use a voltage sensor to obtain the voltage of all transmitting sub-coils at this time, i.e., before the access of the secondary side coil;

[0019] S2, detect whether there is a secondary side coil access, if yes, use a voltage sensor to obtain the voltage of all transmitting sub-coils at this time, i.e., after the access of the secondary side coil, and enter the next step, if not, continue to detect;

[0020] S3, difference the voltage of all transmitting sub-coils before and after the access of the secondary side coil to obtain the voltage variation difference;

[0021] S4, according to the voltage change difference, determine the label of the transmitting sub-coil in the high level voltage state, control the control switch corresponding to the remaining transmitting sub-coil in the closed state.

[0022] The application provides a three-dimensional space multi-transmitting multi-receiving wireless power transmission system and a control method thereof, which comprises the following steps: firstly, a three-dimensional space multi-transmitting structure is designed, the transmitting structure is composed of M transmitting planes which are not parallel to each other, each transmitting plane is arranged with a plurality of identical transmitting sub-coils in an array mode, and the overall shape of the transmitting plane can cover at least one sub-coil, so that the power supply requirement of the plurality of sub-coils in the three-dimensional space can be met. The application also designs a logic control circuit, which comprises an FPGA control module, a plurality of control switches connected in parallel with the transmitting sub-coils one by one, and a plurality of voltage sensors. The FPGA control module collects the voltage of all the transmitting sub-coils before and after the sub-coil is connected, then calculates the voltage change difference, and then controls the control switch to activate the transmitting sub-coil in the high level voltage state according to the voltage change difference, and closes the remaining transmitting sub-coil, so that the size and quantity of the sub-coil can be automatically identified, the invalid transmitting coil can be closed and the corresponding effective transmitting coil can be activated according to the identification result, the anti-deviation capability of the system is improved, and the energy efficiency of the system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is an equivalent circuit diagram of the wireless power transmission system under the SS topology provided by the embodiment of the application;

[0024] Figure 2 is an equivalent circuit diagram of the decoupling of the application; Figure 1

[0025] Figure 3 is a misalignment diagram of the asymmetric system provided by the embodiment of the application;

[0026] Figure 4 is an equal division structure diagram of the primary coil provided by the embodiment of the application;

[0027] Figure 5 is a label diagram of the equal division structure of the primary coil provided by the embodiment of the application;

[0028] Figure 6 is a schematic diagram of the three-dimensional space multi-transmitting structure provided by the embodiment of the application;

[0029] Figure 7 is a space structure diagram of the large sub-coil provided by the embodiment of the application;

[0030] Figure 8 is an equivalent circuit diagram of the system using the large sub-coil provided by the embodiment of the application; ​

[0031] Figure 9 is a schematic diagram of a multi-secondary coil space structure provided by an embodiment of the present application;

[0032] Figure 10 is an equivalent circuit diagram of a system using a multi-secondary coil provided by an embodiment of the present application;

[0033] Figure 11 is a simulation diagram of three states of a primary coil provided by an embodiment of the present application;

[0034] Figure 12 is a simulation diagram of two states of a secondary coil provided by an embodiment of the present application;

[0035] Figure 13 is a simulation diagram of voltage variation difference of two states of a secondary coil provided by an embodiment of the present application;

[0036] Figure 14 is a simulation diagram of a multi-transmit multi-receive coupling mechanism provided by an embodiment of the present application;

[0037] Figure 15 is a simulation diagram of voltage variation difference of a multi-transmit multi-receive coupling mechanism provided by an embodiment of the present application. DETAILED DESCRIPTION

[0038] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments are given only for the purpose of illustration and should not be understood as limiting the present application. The accompanying drawings are used for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present application, because many changes can be made to the present application without departing from the spirit and scope thereof.

[0039] Currently, the commonly used is the MC-WPT system of SS topology, so the present embodiment will use circuit theory to analyze the wireless power transmission system under SS topology, and the equivalent circuit structure diagram is as shown in Figure 1 . Among them, R s is the internal resistance of the voltage source, L1 is the self-inductance of the primary coil, R p1 is the internal resistance of the primary coil, L2 is the self-inductance of the secondary coil, R p2 is the internal resistance of the secondary coil, R L is the load resistance value, C1 is the compensation capacitor in the primary circuit, and C2 is the compensation capacitor in the secondary circuit. The system shown in Figure 1 is KVL equation, and the following can be obtained:

[0040]

[0041] Among them, R1=R p1 +R s , R2=R p2 +RL , respectively, represent the total resistance of the primary side and the secondary side of the system; X1 = ωL1 - 1 / (ωC1), X2 = ωL2 - 1 / ωC2, respectively, represent the reactance of the primary side and the secondary side of the system, and ω represents the working frequency of the system.

[0042] According to formula (1), the decoupling equivalent circuit of Figure 1 is shown in Figure 2 . It can be known from Figure 2 that the difference in the primary inductance voltage change (induced voltage), the secondary side current value and the difference in the secondary inductance voltage change (induced voltage) can be represented as:

[0043]

[0044] It can be known that, in the case of a certain secondary side of the MC-WPT system, the difference in the primary inductance voltage change is related to the mutual inductance and positively correlated. In the case of certain electrical parameters of the MC-WPT system, including the primary side current, the secondary side inductance, the capacitance and the resistance, the size of the secondary side current is related to the mutual inductance between the coils and also positively correlated. In the case of a certain primary side current of the MC-WPT system, the difference in the secondary inductance voltage change is related to the mutual inductance and also positively correlated.

[0045] For the mutual inductance between the coils, the expression thereof can be obtained by using the Newman formula as shown in formula (3).

[0046]

[0047] wherein dl1 and dl2 are the unit length of the primary side coil and the secondary side coil, respectively, r 12 is the equivalent distance between the unit of the primary side coil and the unit of the secondary side coil, C r1 and C r2 respectively represent the closed loop in which the primary side coil and the secondary side coil are located, and μ0 represents the magnetic permeability of vacuum.

[0048] It can be known from the qualitative analysis of formula (3) that, when the centers of the primary side coil and the secondary side coil are aligned, the mutual inductance between the two coils can obtain a large value; when the centers of the primary side coil and the secondary side coil are in a non-aligned state, the mutual inductance between the two coils will greatly decrease, which has an impact on the system energy efficiency.

[0049] When the asymmetric MC-WPT system is used, it is common that the primary side coil and the secondary side coil are in a center misalignment state, as shown in Figure 3 . At this time, the mutual inductance is low, and according to formula (2), if the secondary side current is to reach the desired state, a large primary side current is needed, which will inevitably bring high loss of the system.

[0050] For the asymmetric system offset and high loss of the primary coil and the secondary coil, the primary coil is divided into multiple transmitting sub-coils using the equal division thinking. When the secondary coil is at any position, the transmitting sub-coil opposite to the secondary coil is activated and performs wireless charging, the asymmetric offset condition is converted into the symmetric opposite condition, the mutual inductance is improved and the system loss is reduced, as shown in Figure 4 . The transmitting sub-coils of the primary coil are labeled, as shown in Figure 5 . When the secondary coil is opposite to the transmitting sub-coil L 13 in the primary coil, according to formula (2), the voltage difference of L 13 is the induced voltage, which is much larger than the induced voltage on other transmitting sub-coils. Collecting the induced voltage of all transmitting sub-coils into FPGA and performing algorithm iteration can obtain the position of the transmitting sub-coil opposite to the secondary coil, so as to activate the corresponding coil to perform wireless charging.

[0051] At this time, the primary coil only activates the transmitting sub-coil opposite to the secondary coil, compared with Figure 3 , under the condition of the same primary current, the primary coil using the equal division structure can greatly reduce the primary loss, and at this time, the primary coil and the secondary coil are in the opposite state, and the mutual inductance is also at a high level.

[0052] For the qualitative analysis of the mutual inductance Neumann formula, it can also be obtained that when the two coils are in the vertical state or the same plane state, the mutual inductance will be greatly reduced and will be at a very low level, which can be summarized as the spatial characteristics of the mutual inductance of the coil. According to this analysis and combining the equal division structure thinking, the embodiment proposes a three-dimensional space multi-transmitting multi-receiving wireless power transmission system, which comprises a primary circuit, a logic control circuit and one or more secondary circuits. The primary circuit comprises a direct current source, a high-frequency inverter, a primary resonance compensation network and a three-dimensional space multi-transmitting structure connected in sequence. The secondary circuit comprises a secondary coil, a rectifier filter circuit and a load connected in sequence.

[0053] The three-dimensional space multi-transmitting structure comprises M transmitting planes which are not parallel to each other. Each transmitting plane is arrayed with N identical transmitting sub-coils. The M*N transmitting sub-coils are connected in series, and M≥2 and N≥2. The overall shape of the transmitting plane can cover at least one secondary coil.

[0054] The logic control circuit comprises an FPGA control module, M*N control switches connected in parallel to the FPGA control module, and M*N voltage sensors connected in parallel to the FPGA control module. The M*N control switches are connected in parallel to the M*N transmitting sub-coils one by one.

[0055] M*N voltage sensors are used to acquire the voltages of the M*N transmitting sub-coils before and after the access of the secondary coil. The FPGA control module is used to control the corresponding control switch to activate the transmitting sub-coil with high voltage level difference according to the voltage change difference of each transmitting sub-coil before and after the access of the secondary coil.

[0056] In this embodiment, M=4, N=9, 4 transmitting planes enclose four sides of a cube, and N transmitting sub-coils of each transmitting plane are arranged in an A*A array, and A=3 is taken as an example. The three-dimensional space multi-transmitting structure is shown in Figure 6 When the system is in a large secondary coil state (only one secondary coil, and the secondary coil is larger than the transmitting sub-coil), the spatial structure and equivalent circuit diagram of the MC-WPT system at this time are shown in Figure 7 and Figure 8 . Among them, the primary side resonance compensation network adopts a series compensation capacitor C ts with adjustable capacitance, and the FPGA control module is connected to the series compensation capacitor to adjust the capacitance of the series compensation capacitor according to the number of activated transmitting sub-coils to achieve impedance matching.

[0057] Based on the analysis of the mutual inductance Neumann formula and the mutual inductance spatial characteristics of the magnetic coupling mechanism, the mutual inductance of the 36 transmitting sub-coils can be ignored, and only the mutual inductance between the secondary coil and the 36 transmitting sub-coils needs to be considered.

[0058] Based on formula (2), the transmitting sub-coil induced voltage (inductive voltage change difference) in Figure 8 is calculated to obtain its expression as:

[0059] |ΔU i |=|jωM is I2| (4)

[0060] Where i is the label of the transmitting sub-coil, from 1 to 36, M is (i.e. M Figure 8 in i ) represents the mutual inductance between the transmitting sub-coil L i and the secondary coil L s .

[0061] The FPGA of the logic control circuit receives the inductive voltage change difference on the transmitting coil, and uses the built-in algorithm to obtain the correct transmitting sub-coil label, thereby activating the corresponding transmitting sub-coil. At the same time, the number of activated transmitting sub-coils is calculated, and the adjustable capacitor is adjusted according to the number, to achieve impedance matching, thereby ensuring the normal stable and high energy efficiency operation of the system.

[0062] When the system is in the multi-secondary coil state, the spatial structure schematic diagram and the equivalent circuit diagram of the MC-WPT system at this time are as shown in Figure 9 and Figure 10 .

[0063] As analyzed above, only the mutual inductance between the two secondary coils and the 36 transmitting coils is considered.

[0064] In combination with formula (2), the transmitting sub-coil induced voltage in Figure 11 is calculated to obtain its expression as:

[0065] |ΔU i | = |jωM is1 I 21 | + |jωM is2 I 22 | (5)

[0066] wherein M is1 and M is2 are the mutual inductance of the secondary coil 1, i.e., L s1 and the transmitting sub-coil L i , and the mutual inductance of the secondary coil 2, i.e., L s2 and the transmitting sub-coil L i ; I 21 and I 22 are the secondary side current of the secondary coil 1 and the secondary side current of the secondary coil 2, respectively.

[0067] The primary circuit, the secondary circuit and the logic control circuit of the system have the same functions as above, and the built-in algorithm of the FPGA and the external interface do not need to be changed, which is universal and can normally operate in different situations.

[0068] Therefore, the theoretical expression of the voltage change difference |ΔU i | of the transmitting sub-coil L i i before and after the P secondary coils are connected can be obtained as ω represents the working frequency of the system, I 2j represents the current of the secondary coil L sj , M isj represents the mutual inductance between the transmitting sub-coil L i and the secondary coil L sj , i = 1, 2, …, M * N, j = 1, 2, …, P, P ≥ 1, when P ≥ 2, the P secondary coils are opposite to one transmitting plane or to different transmitting planes.

[0069] Based on the above content, the embodiment of the application further provides a control method of a three-dimensional space multi-transmitting multi-receiving wireless power transmission system, comprising the steps of:

[0070] S1, control all control switches to be in an open state, turn on the primary side circuit, and use a voltage sensor to obtain the voltage of all transmitting sub-coils at this time, i.e., before the secondary side coil is connected;

[0071] S2, detect whether a secondary side coil is connected, if yes, use a voltage sensor to obtain the voltage of all transmitting sub-coils at this time, i.e., after the secondary side coil is connected, and proceed to the next step, if not, continue to detect;

[0072] S3, difference the voltages of all transmitting sub-coils before and after the secondary side coil is connected, to obtain a voltage change difference value (which is the induced voltage of the transmitting sub-coil on the secondary side circuit);

[0073] S4, determine the label of the transmitting sub-coil in a high-level voltage state according to the voltage change difference value, and control the control switches corresponding to the remaining transmitting sub-coils to be in a closed state.

[0074] The so-called high-level voltage state can be defined as follows: half of the highest voltage change difference value is taken as a threshold value, and a voltage change difference value greater than or equal to the threshold value is considered to be in a high-level voltage state, otherwise it is in a low-level voltage state.

[0075] In summary, the three-dimensional space multi-transmitting multi-receiving wireless power transmission system and the control method thereof provided by the embodiment first design a three-dimensional space multi-transmitting structure, which is composed of M mutually non-parallel transmitting planes, each transmitting plane is arranged in an array with multiple identical transmitting sub-coils, and the overall shape of the transmitting plane can cover at least one secondary side coil, which can meet the demand of powering multiple secondary side coils in three-dimensional space. The application also designs a logic control circuit, which includes an FPGA control module, multiple control switches connected in parallel one-to-one with the transmitting sub-coils, and multiple voltage sensors. The FPGA control module collects the voltages of all transmitting sub-coils before and after the secondary side coil is connected through the voltage sensor, then calculates the voltage change difference value, and then activates the transmitting sub-coil in a high-level voltage state by controlling the control switch according to the voltage change difference value, while closing the remaining transmitting sub-coils, to achieve the purpose of automatically identifying the size and number of the secondary side coil, further closing the invalid transmitting coil and activating the corresponding effective transmitting coil according to the identification result, effectively improving the anti-deviation ability of the system and improving the energy efficiency of the system.

[0076] The simulation analysis is as follows.

[0077] To study the advantages of the equal division structure, the original large coil without splitting is compared with the small coil group after splitting, and the secondary coil is of the same size and specification. Based on the simulation software COMSOL, the physical models of the large coil and the secondary coil center alignment, the large coil and the secondary coil center misalignment, and the small coil and the secondary coil center alignment are established, only the original side current is set, the induced voltage of the secondary coil is simulated and verified, and the coil parameter setting is shown in Table 1.

[0078] Table 1

[0079]

[0080]

[0081] To study the automatic recognition ability of the designed primary coil array, the secondary coil is set to different sizes for comparison, and is set to a large secondary coil and a small secondary coil respectively. Based on the simulation software COMSOL, the physical models of the single-sided coil array with large and small secondary coils are established, only the secondary current is set, and the inductance voltage change difference of the primary coil array is simulated, and the coil setting is shown in Table 2.

[0082] Table 2

[0083] Type Parameter Value [N1] Primary coil array single coil turns 10 [WC th ]]> Primary coil array coil spacing 0.01m N Primary coil array coil number 9 [a1] Primary small coil inner diameter 0.02m [R1] Primary small coil outer diameter 0.1m <![CDATA[N R1 ]]> Secondary large coil turns 20 <![CDATA[N R2 ]]> Secondary small coil turns 10 [a2] Secondary coil inner diameter 0.02m [R r1 ]]> Secondary large coil outer diameter 0.2m [R r2 ]] Secondary small coil outer diameter 0.08m D Primary and secondary coil spacing 0.03m [I2] Secondary coil current 1A

[0084] To study the recognition ability of the designed three-dimensional magnetic coupling mechanism space multiple receiving coils, N receiving coils are placed near the magnetic coupling mechanism, and the simulation software COMSOL is used to set only the secondary current, and the inductance voltage change difference of the primary coil is simulated and verified. This embodiment takes two receiving coils as an example to establish a simulation physical model, and the coil parameter setting is shown in Table 3.

[0085] Table 3

[0086]

[0087]

[0088] The finite element simulation software comsol is used to simulate the original side coil and the secondary side coil according to the coil parameters given in Table 1, and the schematic diagram of the three system states after simulation is shown in Figure 11 , wherein (a), (b), (c) respectively correspond to the original large coil alignment state, the original large coil misalignment state, and the original small coil alignment state.

[0089] For the three states, the distance D between the primary coil and the secondary coil is set as a constant, the primary coil current is set as the same size, the induced voltage of the secondary coil in the three states is simulated, and the mutual inductance between the primary coil and the secondary coil in different states is analyzed by using the induced voltage of the secondary coil in the three different states and combining formula (3). The secondary induced voltages in the three states obtained by simulation are shown in Table 4.

[0090] Table 4

[0091] State [Delta]U2 / V Primary large coil aligned state 2.84 Primary large coil misaligned state 0.45 Primary small coil aligned state 0.8

[0092] From Figure 11 It can be seen from the simulation results of Table 4 that when the primary large coil and the secondary coil are in the aligned state, the induced voltage on the secondary coil obtains the maximum value among the three, and according to formula (4), the mutual inductance between the primary and secondary coils at this time is also the maximum. By comparing the unaligned state of the primary large coil and the aligned state of the primary small coil, it can also be found that the induced voltage obtained when the secondary coil and the primary small coil are in the aligned state is much higher than that when the secondary coil and the primary large coil are in the unaligned state, that is, the mutual inductance will be high. Therefore, the primary large coil is split by using the equal division idea, and under the condition that the primary current is constant, the induced voltage of the secondary coil can be improved, and combined with formula (1), that is, the induced current of the secondary coil can be improved.

[0093] The finite element simulation software comsol is used to simulate the primary coil and the secondary coil according to the coil parameters given in Table 2, and the schematic diagram of the two system states after simulation is shown in Figure 12 , wherein (a) and (b) correspond to the secondary large coil state and the secondary small coil state, respectively.

[0094] In order to verify the recognition ability of the primary coil array proposed in this embodiment to different secondary coils, the larger size secondary coil and the smaller size secondary coil are simulated. Since the recognition ability is determined by formula (2), only the secondary coil is set with current, and the primary inductance voltage is detected to obtain the difference of the primary inductance voltage change when the system is normally running. The primary coil array induced voltage in the two states obtained by simulation is shown in Figure 13 , wherein (a) and (b) correspond to the secondary large coil simulation result and the secondary small coil simulation result, respectively.

[0095] From Figure 13 the simulation results of Table 4, it can be seen that when the primary coil is facing the large size secondary coil, the coils L 12 , L 13 , L 22 and L 23All are in a high level voltage state, four small primary side coils that the large size secondary side coil is directly opposite can be identified, thereby activating these coils to carry out wireless charging. When the primary side coil is opposite to the small size secondary side coil, the coil L 13 in the array is in a high level voltage state, and the small primary side coil that the small size secondary side coil is directly opposite can be identified, thereby activating the coil to carry out wireless charging. Therefore, whether the large size or the small size secondary side coil can be correctly identified by the primary side coil array, and the primary side coil array has good identification ability.

[0096] The finite element simulation software comsol is used to simulate the primary side coil and the secondary side coil according to the coil parameters given in Table 3, and the system state after simulation is shown in Figure 14 .

[0097] In order to verify the identification ability of the three-dimensional magnetic coupling mechanism to multiple secondary side coils, two secondary side coils are provided, which are located in different planes. By using the superposition theorem, only the current of the secondary side coil is set, and the primary side inductance voltage of each small coil in the three-dimensional magnetic coupling mechanism during normal operation of the system can be obtained by detecting the primary side inductance voltage, thereby verifying the identification ability of the system. The inductance voltage difference of each small coil of the three-dimensional magnetic coupling mechanism obtained by simulation is shown in Figure 15 .

[0098] From the simulation results of Figure 15 , it can be seen that when multiple receiving coils are located near the three-dimensional magnetic coupling mechanism, the magnetic coupling mechanism can also accurately identify the positions of the corresponding secondary side coils. The voltage difference of the coil L 21 on the first plane and the voltage difference of the coil L 13 on the second plane are obviously higher than those of other coils, that is, the identification of the small coils directly opposite the secondary side coils can be judged, thereby activating these coils to carry out wireless charging.

[0099] From the above simulation analysis, it can be seen that the equal division structure coil array and the three-dimensional magnetic coupling mechanism composed of the equal division structure coil array have good multi-receiving coil identification ability. By collecting the inductance voltage difference of the primary side coil, the position of the secondary side coil is identified, and the transmitting sub-coils directly opposite are activated. Compared with the complete large coil, it has better anti-offset ability, and because of lower primary side loss, it can have better system energy efficiency.

[0100] In summary, the embodiment splits the primary large coil into an array of primary coils by analyzing the mutual inductance of the asymmetric MC-WPT system and starting from the idea of dividing the whole into parts. With the rule that the mutual inductance is minimal when two coils are in the same plane or perpendicular to each other obtained by Newman's formula, a three-dimensional magnetic coupling mechanism with multiple transmission and multiple reception is designed. When the system is in working condition, the FPGA in the system can collect the voltage difference of each transmission coil through the voltage sensor by using the feature that the voltage on the primary inductance changes, thereby identifying the position of the secondary coil, closing other invalid coils, and only activating the coil directly opposite to the secondary coil, so as to realize high anti-offset capability and high energy efficiency of the system.

[0101] The embodiment uses comsol finite element simulation software to model the primary coil array and three-dimensional magnetic coupling mechanism, and verifies the advantages of the mutual inductance characteristics of the primary coil array, the matching ability of different secondary coils, and the identification ability of multiple secondary coils. The system can automatically identify and activate the corresponding coil for wireless charging according to different situations.

[0102] The three-dimensional magnetic coupling mechanism designed in the embodiment takes four sides as the background and can be used as a design reference for other types of magnetic coupling mechanisms. The designed three-dimensional magnetic coupling mechanism is suitable for secondary coils of different sizes and quantities, has good anti-offset capability, and can improve the transmission efficiency of the system. It has a good promoting effect on the promotion and application of wireless charging in different application backgrounds and has good practical application value.

[0103] The above embodiment is a preferred embodiment of the present application, but the embodiments of the present application are not limited by the above embodiment, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and all are included in the protection scope of the present application.

Claims

1. A three-dimensional spatial multi-transmitter, multi-receiver wireless power transmission system, characterized in that, It includes a primary-side circuit, a logic control circuit, and one or more secondary-side circuits. The primary-side circuit includes a DC source, a high-frequency inverter, a primary-side resonant compensation network, and a three-dimensional multi-emitting structure connected in sequence. The secondary-side circuit includes a secondary-side coil, a rectifier and filter circuit, and a load connected in sequence. The three-dimensional spatial multi-emission structure includes There are several non-parallel emission planes, each of which is arranged in an array. Two identical transmitter coils, The transmitting sub-coils are connected in series. The overall shape of the transmitting plane can cover at least one of the secondary coils; The logic control circuit includes an FPGA control module and components connected in parallel to the FPGA control module. A control switch is connected in parallel to the FPGA control module. One voltage sensor, A control switch and Each transmitting sub-coil is connected in parallel in a one-to-one manner; One voltage sensor is used for one-to-one acquisition. The voltage of each transmitting sub-coil before and after the secondary coil is connected; The FPGA control module is used to activate the transmitting sub-coil whose voltage change difference is in a high-level voltage state by controlling the corresponding control switch according to the voltage change difference of each transmitting sub-coil before and after the secondary coil is connected. The high-level voltage state is defined as follows: if the voltage change difference is greater than or equal to half of the highest voltage change difference as a threshold, the corresponding transmitting sub-coil is considered to be in a high-level voltage state, and otherwise it is in a low-level voltage state.

2. The three-dimensional spatial multi-transmitter multi-receiver wireless power transmission system according to claim 1, characterized in that: The transmitter coil labeled i exist Voltage difference before and after the secondary coil is connected The theoretical expression is , Indicates the system's operating frequency. Indicates the secondary coil The current, Indicates the transmitting sub-coil With secondary coil Mutual intuition between them , , .

3. The three-dimensional spatial multi-transmitter multi-receiver wireless power transmission system according to claim 2, characterized in that: The primary-side resonant compensation network uses a series compensation capacitor with adjustable capacitance. The FPGA control module is connected to the series compensation capacitor to adjust its capacitance value according to the number of activated transmitter sub-coils, so as to achieve impedance matching.

4. The three-dimensional spatial multi-transmitter multi-receiver wireless power transmission system according to claim 3, characterized in that: Each emission plane One transmitting sub-coil Array arrangement, .

5. The three-dimensional spatial multi-transmitter multi-receiver wireless power transmission system according to claim 4, characterized in that: , , The emitting planes form the four sides of a cube.

6. The three-dimensional spatial multi-transmitter multi-receiver wireless power transmission system according to claim 2, characterized in that: when hour, Each secondary coil is opposite to a single transmitting plane or to different transmitting planes.

7. A control method for a three-dimensional spatial multiple-transmitter multiple-receiver wireless power transmission system, specifically for the three-dimensional spatial multiple-transmitter multiple-receiver wireless power transmission system according to any one of claims 1 to 6, characterized in that, Including the following steps: S1. Control all control switches to the off state, turn on the primary circuit, and use a voltage sensor to obtain the voltage of all transmitting sub-coils at this time, i.e., before the secondary coils are connected. S2. Detect whether a secondary coil is connected. If so, use a voltage sensor to obtain the voltage of all transmitting sub-coils at this time, i.e., after the secondary coil is connected, and proceed to the next step. Otherwise, continue to detect. S3. Calculate the voltage difference of all transmitting sub-coils before and after the secondary coil is connected to obtain the voltage change difference value; S4. Determine the label of the transmitter coil in the high voltage state based on the voltage change difference, and control the control switches corresponding to the other transmitter coils to be in the closed state.

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