Full relay node output multistage WPT magnetic coupling mechanism and system

Abstract

The invention relates to the technical field of wireless power transmission (WPT), particularly discloses a multi-stage WPT magnetic coupling mechanism and system with full relay node output, and designs a special coil arrangement structure aiming at the problem that each relay node in a multi-stage WPT system is difficult to realize independent and stable constant-voltage output. Each stage of relay node is formed by connecting coils which are nested inside and outside in series, four different combinations of annular coils and double semicircular coils are adopted, and a receiving node adopts a coil structure consistent with the type of the inner coil of the last stage of relay node, so that directional coupling and decoupling of magnetic fields between adjacent nodes are realized, and a foundation is laid for independent power supply of each node. The correspondingly constructed system can accurately regulate and control the output voltage of each relay node through specific circuit topology and parameter design. According to the invention, stable constant voltage output at all relay nodes is realized, and the method is suitable for monitoring scenes requiring distributed reliable power supply, such as the interior of a high-voltage composite insulator.

Description

Multi-stage WPT magnetic coupling mechanism and system with full relay node output Technical Field

[0001] This invention relates to the field of wireless power transfer (WPT) technology, and more particularly to a multi-stage WPT magnetic coupling mechanism and system with full relay node output. Background Technology

[0002] Composite insulators, with their advantages of light weight, strong hydrophobicity, and excellent resistance to pollution flashover, have become the core insulation components of high-voltage and ultra-high-voltage transmission lines, and their operating condition directly determines the reliability of the transmission system. However, during long-term outdoor service, composite insulators are continuously subjected to the coupled effects of multiple environmental factors such as strong electric fields, ultraviolet radiation, acid rain corrosion, and pollution deposition, gradually leading to deterioration phenomena such as core rod embrittlement, sheath cracking, and interface breakdown. This type of deterioration is characterized by its insidious and gradual nature, making it difficult to accurately identify through manual inspection in the early stages. Once the deterioration develops to a critical state, it can easily trigger serious accidents such as insulator flashover and breakage, causing large-scale power outages.

[0003] With the advancement of smart grids, online, real-time, and distributed condition monitoring of composite insulators has become a necessary trend, and stable power supply to monitoring equipment is the core bottleneck in achieving this goal. Wireless power supply technology achieves contactless power transmission through electromagnetic field coupling, fundamentally solving the insulation and wiring problems of traditional power supply methods, and has become an ideal technical path for powering high-voltage equipment. Multi-stage WPT further improves the transmission distance by adding relay coils between the transmitting and receiving coils. Outputs near each relay node can precisely interface with distributed monitoring equipment deployed in the insulator string, meeting the spatial layout requirements for composite insulator monitoring.

[0004] However, distributed monitoring equipment using composite insulators typically requires high stability of the power supply voltage; excessive voltage fluctuations can lead to distorted monitoring data and shortened equipment lifespan. Therefore, achieving constant voltage output at each relay node of a multi-level WPT is a core technical requirement for constructing a reliable and efficient composite insulator monitoring power supply system. Summary of the Invention

[0005] This invention provides a multi-stage WPT magnetic coupling mechanism and system with full relay node output. The technical problem it solves is: how to design a multi-stage WPT magnetic coupling mechanism and system that can achieve stable output at all relay nodes.

[0006] To address the above technical problems, this invention provides a multi-stage WPT magnetic coupling mechanism with full relay node output, comprising a transmitting node, N-2 levels of relay nodes, and a receiving node arranged sequentially according to the energy transmission direction, where N≥3; each relay node is composed of coaxially nested outer and inner coils connected in series; the coil structures used by the transmitting node, the receiving node, the outer coil, and the inner coil are toroidal coils wound in a planar spiral manner or double semi-circular toroidal coils, transmitting energy through coils of the same structural type between adjacent nodes, while achieving magnetic circuit decoupling through coils of different structural types; each double semi-circular toroidal coil is composed of two semi-circular toroidal coils connected in series with opposite winding directions, placed coplanarly, and with their straight edges joined together to form a complete circle, generating two magnetic fields with opposite polarization directions when current flows through the two semi-circular toroidal coils.

[0007] Preferably, the transmitting node uses the loop coil; the relay node uses any one of the first type of combined coil, the second type of combined coil, the third type of combined coil, and the fourth type of combined coil, and adjacent relay nodes use different combined coils. The outer and inner coils of the first type of combined coil are both loop coils, the outer coil of the second type of combined coil is a loop coil and the inner coil is a double semi-circular loop coil, the outer and inner coils of the third type of combined coil are both double semi-circular loop coils, and the outer coil of the fourth type of combined coil is a double semi-circular loop coil and the inner coil is a loop coil; the coil type of the receiving node is consistent with the inner coil type of the last-level relay node.

[0008] Preferably, the N-2 level relay nodes are arranged cyclically along the energy transmission direction according to a first arrangement or a second arrangement. The arrangement order of the first arrangement is the first type of combined coil, the second type of combined coil, the third type of combined coil, and the fourth type of combined coil; the arrangement order of the second arrangement is the fourth type of combined coil, the third type of combined coil, the second type of combined coil, and the first type of combined coil.

[0009] The present invention also provides a multi-stage WPT system with full relay node output, the key feature of which is: including a high-frequency inverter network, a transmitter node network, N-2 relay node networks, a receiver node network, and N-1 identical rectifier networks that connect the N-2 relay node networks and the receiver node network one-to-one. The transmitter node network, the N-2 relay node networks, and the receiver node network adopt the multi-stage WPT magnetic coupling mechanism with full relay node output.

[0010] Preferably, the m-th level relay node network includes two branches: an outer coil branch and an inner coil branch, where m = 1, 2, ..., N-2. If:

[0011] If the m-th level relay node network uses either the first type of combined coil or the third type of combined coil, then the outer coil branch includes the self-inductance of the series-connected outer coil (m+1). Parasitic resistance With compensation capacitor The inner coil branch includes the self-inductance of the inner coil (m+1)' connected in series. Parasitic resistance Compensation capacitor and the equivalent input resistance of the load derived from the rectifier network. Furthermore, a capacitor is connected in parallel between the outer coil branch and the inner coil branch. ;

[0012] If the m-th level relay node network uses a second-type or fourth-type combined coil, then the outer coil branch includes the self-inductance of the series-connected outer coils (m+1). Parasitic resistance With compensation capacitor The inner coil branch includes the self-inductance of the inner coil (m+1)' connected in series. Parasitic resistance and compensation capacitors Furthermore, the equivalent input resistance of the load, which is equivalent to the load network of this stage, is connected in parallel between the outer coil branch and the inner coil branch. .

[0013] Preferably, the transmitting node network includes the self-inductance of coil 1 connected in series. Parasitic resistance and the series compensation capacitor of the circuit The receiving node network includes the self-inductance of a series-connected coil N. Parasitic resistance Series compensation capacitor and the equivalent input resistance of the load derived from the rectifier network of this stage. .

[0014] Preferably, for the m-th level relay node network employing either the first type of combined coil or the third type of combined coil, the mutual inductance between its inner and outer coils is... , Indicates the actual measured mutual inductance. This is the system's operating angular frequency.

[0015] Preferably, based on coupling theory, each coil circuit of the same type of coil structure needs to meet the resonance and decoupling conditions.

[0016] Preferably, for the m-th level relay node network where m is an odd number, in order to achieve the target load output value... Required parallel capacitor , This represents the effective value of the AC voltage output by the high-frequency inverter. This represents the mutual inductance between the outer coil of the m-th level relay node network and the inner coil of the preceding level node network, as measured in actual measurements. When m=1, The mutual inductance between the outer coil of the first-level relay node network and the coil of the transmitting node network. .

[0017] Preferably, the parameter design process of this system includes:

[0018] S1. Initialize the system's DC input voltage. System operating frequency Each DC load resistor System parameters, set target values ​​for load output voltage of each relay node. ;

[0019] S2. Using simulation software, construct a three-dimensional model of the magnetic coupling mechanism at the output of the designed full relay node, based on the target value of the load output voltage. The number of turns required for the outer coil in an even-level relay node is determined by scanning parameters.

[0020] S3. Simulate and measure the coil parameters, including coil self-inductance, mutual inductance, and internal resistance. Substitute the known system parameters into the reflection impedance expression for each loop and the current expression for each coil loop to obtain the current value flowing through each coil loop.

[0021] S4. Substitute the known and measured system parameters into the circuit parallel capacitance expression to calculate the circuit parallel capacitance in odd-level relay nodes.

[0022] S5. Substitute the coil currents and parallel capacitance values ​​obtained from the above steps back into the same type of coil resonance and decoupling conditions to finally calculate the size of the series compensation capacitor required for each circuit.

[0023] This invention provides a multi-stage WPT magnetic coupling mechanism and system with full relay node output. Addressing the technical problem in multi-stage WPT systems where the output voltage of each relay node is greatly affected by load changes, making it difficult to achieve independent constant voltage output for all nodes, a special magnetic coupling mechanism is designed. This mechanism arranges a transmitting node, multiple relay nodes, and a receiving node sequentially along the energy transmission direction. The transmitting node uses a planar helical ring coil; the relay nodes are composed of coaxially nested inner and outer coils connected in series. The inner and outer coils can be selected as ring coils or the aforementioned double semi-circular ring coils, thus defining four combination types; the receiving node uses a coil structure consistent with the inner coil type of the last stage relay node. This magnetic coupling mechanism allows coils with the same structural type (with the same magnetic field polarization direction) between adjacent nodes to couple and transmit energy, while coils with different structural types (with perpendicular magnetic field polarization directions) achieve magnetic circuit decoupling, thereby creating conditions for independent output of each relay node.

[0024] At the system level, a complete circuit including a high-frequency inverter, various coil networks, and a rectifier network was constructed in conjunction with the magnetic coupling mechanism. Corresponding circuit topologies (especially the connection positions of load resistors and compensation capacitors) were designed for different types of relay node networks. The parameter calculation and configuration process required to satisfy system resonance, decoupling conditions, and achieve the target output voltage was derived. This included precisely controlling the output voltage of each node by adjusting the number of turns of the external coil in even-numbered relay nodes or configuring parallel compensation capacitors in odd-numbered relay nodes.

[0025] This invention enables a stable and independent constant voltage output to the load at each relay node in a multi-level WPT system. The output voltage remains essentially constant with minimal deviation even when the load resistance changes significantly. This greatly improves the reliability and adaptability of the system for powering distributed monitoring equipment, making it particularly suitable for online monitoring scenarios of high-voltage electrical equipment with complex structures, dispersed power supply points, and requirements for stable voltage. Simulation results verify that the system can achieve the target output voltage at all relay nodes and possesses good load independence and output stability. Attached Figure Description

[0026] Figure 1 is a magnetic coupling mechanism diagram of a 6-level WPT system provided in an embodiment of the present invention;

[0027] Figure 2 is an application example diagram of the multi-stage WPT magnetic coupling mechanism with full relay node output provided in the embodiment of the present invention;

[0028] Figure 3 is a circuit diagram of a 6-level WPT system provided in an embodiment of the present invention;

[0029] Figure 4 is a circuit diagram of the full-bridge rectifier at the receiving end provided in an embodiment of the present invention;

[0030] Figure 5 is a controlled source and T-type equivalent circuit diagram of the output of the full relay node of the 6-level WPT system provided in the embodiment of the present invention;

[0031] Figure 6 is a flowchart of the system circuit parameter solving steps provided in an embodiment of the present invention;

[0032] Figure 7 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0033] Figure 8 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0034] Figure 9 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0035] Figure 10 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0036] Figure 11 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0037] Figure 12 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0038] Figure 13 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0039] Figure 14 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0040] Figure 15 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0041] Figure 16 shows the inverter output voltage provided in the embodiment of the present invention. With coil current Waveform diagram;

[0042] Figure 17 shows the load resistor provided in the embodiment of the present invention. Curves showing the output voltage variation of various loads under a 50~400Ω range;

[0043] Figure 18 shows the load resistor provided in the embodiment of the present invention. Curves showing the output voltage variation of various loads under a 50~400Ω range;

[0044] Figure 19 shows the load resistor provided in the embodiment of the present invention. Curves showing the output voltage variation of various loads under a 50~400Ω range;

[0045] Figure 20 shows the load resistor provided in the embodiment of the present invention. Output voltage variation curves for various loads ranging from 50 to 400Ω. Detailed Implementation

[0046] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the present invention. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0047] This invention first provides a multi-stage WPT magnetic coupling mechanism with full relay node output. The coils of this magnetic coupling mechanism are all wound with Litz wire in a planar spiral manner. Its core types include the following two: the first is a toroidal coil, which is a planar spiral coil with a complete toroidal structure; the second is a double semi-circular toroidal coil, which is formed by connecting two semi-circular toroidal coils with opposite winding directions, placed coplanarly, and whose straight edges are joined together to form a complete circle. This ensures that when current flows through the two semi-circular toroidal coils, two magnetic fields with opposite polarization directions are generated. Arranged in order of energy transmission direction, the system consists of a transmitting node, N-2 levels of relay nodes, and a receiving node (a total of N levels), where N≥3. The relay nodes (coils 2 to N-1) are formed by coaxially nested outer and inner coils connected in series. The transmitting node, receiving node, outer coil, and inner coil can all be toroidal coils or double semi-circular toroidal coils.

[0048] N-2 level repeater nodes are arranged in a cyclical pattern according to either the first arrangement of type 1 combined coil, type 2 combined coil, type 3 combined coil, and type 4 combined coil, or the second arrangement of type 4 combined coil, type 3 combined coil, type 2 combined coil, and type 1 combined coil. The outer and inner coils of the type 1 combined coil are both loop coils. The outer coil of the type 2 combined coil is a loop coil and the inner coil is a double semi-circular loop coil. The outer and inner coils of the type 3 combined coil are both double semi-circular loop coils. The outer coil of the type 4 combined coil is a double semi-circular loop coil and the inner coil is a loop coil.

[0049] The transmitting node (coil 1) uses the aforementioned loop coil. The coil type of the receiving node (coil N) is consistent with the inner coil type of the (N-2)th level relay node (i.e., the last level relay node). If the inner coil of the (N-2)th level relay node is a loop coil, the receiving node uses the aforementioned loop coil; if the inner coil of the (N-2)th level relay node is a double semi-circular loop coil, the receiving node uses the aforementioned double semi-circular loop coil.

[0050] This embodiment uses the N-2 level repeater nodes arranged in the first manner as an example. In this case, the (4k-3) level repeater node (k is a positive integer and 4k-3≤N-2) has an outer coil (coil (4k-2)) and a nested inner coil (coil (4k-2)') that are both toroidal coils; the (4k-2) level repeater node has an outer coil (coil (4k-1)) that is a toroidal coil and a nested inner coil (coil (4k-1)') that is a double semi-circular toroidal coil; the (4k-1) level repeater node has an outer coil (coil (4k)) and a nested inner coil (coil (4k)') that are both double semi-circular toroidal coils; and the 4k level repeater node has an outer coil (coil (4k+1)) that is a double semi-circular toroidal coil and a nested inner coil (coil (4k+1)') that is a toroidal coil.

[0051] Taking the first arrangement with N=6 as an example, according to the energy transmission direction of the multi-level WPT, each node is numbered sequentially from node 1 to node 6, and the nodes are divided into different types: node 1 is the transmitting node; nodes 2 to 5 are all relay nodes, for a total of 4 levels. The level number of the relay node is denoted as m (m=1,2,3,4), which represents the m-th level relay node. The m-th level relay node includes an outer coil (m+1) and an inner coil (m+1)'. The structure of the resulting 6-level WPT magnetic coupling mechanism is shown in Figure 1. For the first-level repeater node, the outer coil is coil 2, and the nested inner coil is coil 2', both of which are loop coils. For the second-level repeater node, the outer coil is coil 3, and the nested inner coil is coil 3', where coil 3 is a loop coil and coil 3' is a double semi-circular loop coil. For the third-level repeater node, the outer coil is coil 4, and the nested inner coil is coil 4', where both coil 4 and coil 4' are double semi-circular loop coils. For the fourth-level repeater node, the outer coil is coil 5, and the nested inner coil is coil 5', where coil 5 is a double semi-circular loop coil and coil 5' is a loop coil. The sixth-level node is a receiving node, and its coil is a loop coil, consistent with the type of the inner coil (i.e., coil 5') at the fourth-level repeater node.

[0052] As an application example, a multi-level WPT system with full relay node output is applied inside a composite insulator to monitor the working status of the composite insulator under high-voltage operating conditions. A schematic diagram of the specific application is shown in Figure 2.

[0053] The embodiments of the present invention provide a corresponding multi-stage WPT system based on the multi-stage WPT magnetic coupling mechanism with full relay node output shown above, including a high-frequency inverter network, a transmitter node network, N-2 relay node networks, a receiver node network, and N-1 identical rectifier networks that connect the N-2 relay node networks and the receiver node networks one-to-one.

[0054] High-frequency inverter networks include DC input voltage sources and by , , , A full-bridge inverter circuit composed of four MOSFET switches, the inverter's output voltage As the AC input of the transmitting node network.

[0055] The transmitter node network includes the self-inductance of the transmitter coils (coil 1) connected in series. Parasitic resistance and the series compensation capacitor of the circuit .

[0056] The m-th level relay node network (m=1,2,…,N-2) includes two branches: an outer coil branch and an inner coil branch. If:

[0057] If the m-th level relay node network uses either the first type of combined coil or the third type of combined coil, then the outer coil branch includes the self-inductance of the series-connected outer coil (m+1). Parasitic resistance With compensation capacitor The inner coil branch includes the self-inductance of the inner coil (m+1)' connected in series. Parasitic resistance Compensation capacitor and the equivalent input resistance of the load derived from the rectifier network. Furthermore, a capacitor is connected in parallel between the outer coil branch and the inner coil branch. ;

[0058] If the m-th level relay node network uses a second-type or fourth-type combined coil, then the outer coil branch includes the self-inductance of the series-connected outer coils (m+1). Parasitic resistance With compensation capacitor The inner coil branch includes the self-inductance of the inner coil (m+1)' connected in series. Parasitic resistance and compensation capacitors Furthermore, the equivalent input resistance of the load, which is equivalent to the load network of this stage, is connected in parallel between the outer coil branch and the inner coil branch. .

[0059] The receiving node network includes the self-inductance of coil N connected in series. Parasitic resistance Series compensation capacitor and the equivalent input resistance of the load derived from the rectifier network of this stage. .

[0060] M ij (i, j ≤ N, i ≠ j) represents the mutual inductance between coil i and coil j. For the m-th level relay node network where m is odd, it uses either the first type of combined coil or the third type of combined coil. The mutual inductance between the inner and outer coils is expressed as: .

[0061] For the m-th relay node when m is even, the magnetic field polarization directions generated by the inner and outer coils of the second type of combined coil structure are perpendicular to each other, and the magnetic flux they generate cancels each other out in the other coil. Theoretically, this can achieve near-complete decoupling of the magnetic circuit. Since the magnetic circuit interference between the two is negligible, the inner and outer coils only maintain a circuit-level connection, and the output voltage on their equivalent load will serve as the input voltage source for the inner coil circuit. The magnetic circuit decoupling characteristics of the inner and outer coils using the fourth type of combined coil are consistent with those of the relay node using the second type of combined coil, only the coil combination is reversed.

[0062] In a multi-stage WPT energy transfer path, between nodes, coils of the same structural type have the same magnetic field polarization direction and are magnetically coupled; coils of different structural types have perpendicular magnetic field polarization directions and are magnetically decoupled from each other.

[0063] Taking N=6 as an example, the circuit structure of a multi-stage WPT system with full relay node output is shown in Figure 3. The system consists of a high-frequency inverter network, a transmitter node network, four relay node networks, a receiver node network, and five identical rectifier networks. The transmitter node network includes the self-inductance of coil 1. Parasitic resistance and the series compensation capacitor of the circuit The first-level relay node network includes two branches: coil 2 and coil 2'. The self-inductance of coil 2... Parasitic resistance With compensation capacitor The interconnected components form the first branch of the first-level relay node network, and the second branch is formed by the self-inductance of coil 2'. Parasitic resistance Compensation capacitor and load equivalent input resistance The components are connected in series, and a capacitor is connected in parallel between the first branch and the second branch. The second-level relay node network consists of two branches: coil 3 and coil 3'. The first branch is the self-inductance of coil 3. Parasitic resistance and the compensation capacitor connected in series with it The second branch is the self-inductance of coil 3'. Parasitic resistance and the compensation capacitor connected in series with it The two branches are respectively connected to the equivalent input resistance of the load. Parallel connection. The third-level relay node network includes two branches: magnetically coupled coil 4 and coil 4'. The self-inductance of coil 4... Parasitic resistance With compensation capacitor The interconnected circuits form the first branch of the third-level relay node network, and the self-inductance of coil 4' is... Parasitic resistance Compensation capacitor and load equivalent input resistance The first branch is connected in series to form the second branch, and a capacitor is connected in parallel between the first branch and the second branch. The fourth-level relay node network consists of two branches: coil 5 and coil 5'. The first branch is the self-inductance of coil 5. Parasitic resistance and the compensation capacitor connected in series with it The second branch is the self-inductance of coil 5'. Parasitic resistance and the compensation capacitor connected in series with it The two branches are respectively connected to the equivalent input resistance of the load. Parallel connection. The receiving node network includes the self-inductance of coil 6. Parasitic resistance Series compensation capacitor and load equivalent input resistance .

[0064] The relationship between the high-frequency inverter network output voltage and the DC input voltage is as follows:

[0065] ,

[0066] in, This represents the effective value of the AC voltage output by the high-frequency inverter. This indicates the DC input voltage.

[0067] The equivalent input resistance of the rectifier network can be expressed as:

[0068] ,

[0069] The output load resistance value is There are a total of N-1 output load resistors, namely , … .

[0070] For ease of subsequent analysis, the parasitic resistance of the coil is ignored, that is:

[0071] .

[0072] Taking N=6 as an example again, all 5 rectifier networks are composed of , , , A full-bridge uncontrolled rectifier circuit consisting of four diodes and a DC filter capacitor. and DC output load The composition is shown in Figure 4. Load equivalent input resistance. Looking from the input of the rectifier network towards the DC output load The total equivalent resistance of the terminals, where i = 1, 2, 3, 4, 5.

[0073] From the complete multi-stage WPT circuit topology of the full relay node output shown in Figure 3, the controlled source and T-type equivalent circuit diagram of the full relay node output can be obtained, as shown in Figure 5. It is the equivalent mutual inductance between coil 2 and coil 2' in the first-level relay node. The equivalent mutual inductance between coil 4 and coil 4' in the third-level relay node satisfies the following equation:

[0074] ,

[0075] in, The actual measured mutual inductance between coil 2 and coil 2' at the first-level relay node. The actual measured mutual inductance between coil 4 and coil 4' at the third-level relay node.

[0076] Therefore, the simplified form The equivalent mutual inductance at the first-level relay node and the third-level relay node can be obtained. , They are respectively:

[0077] ,

[0078] Therefore, for a relay node network of the mth level (where m is an odd number) using either a first-type or third-type combined coil, the mutual inductance between its inner and outer coils... .

[0079] At the second-level relay node, the outer coil 3 is a circular loop coil, and the nested inner coil 3' is a double semi-circular loop coil. The magnetic field polarization directions generated by the two coil structures are perpendicular to each other, and their magnetic flux cancels each other out in the other coil. Theoretically, coils 3 and 3' can achieve near-complete decoupling of their magnetic circuits. Given that their magnetic circuit interference is negligible, coils 3 and 3' only maintain a circuit-level connection. The equivalent load at the second-level relay node... Output voltage This will serve as the input voltage source in the inner coil 3' circuit. Similarly, at the fourth-level relay node, coil 5 and coil 5' can also achieve near-complete magnetic circuit decoupling, and their magnetic circuit interference is negligible. The equivalent load at the fourth-level relay node... Output voltage It will serve as the input voltage source in the inner coil 5' circuit.

[0080] In a 6-level WPT energy transfer path, coils of the same structural type have the same magnetic field polarization direction, resulting in magnetic circuit coupling; coils of different structural types have perpendicular magnetic field polarization directions, resulting in magnetic circuit decoupling. Based on the definition of the magnetic coupling mechanism of the relay node, it can be seen that coil 1', coil 2, coil 2', and coil 3 are all toroidal coils; coil 3', coil 4, coil 4', and coil 5 are all double semi-circular toroidal coils; and coil 5' and coil 6 are both toroidal coils.

[0081] Based on coupling theory, the following resonance and decoupling conditions must be met for coil 1, coil 2, coil 2', and coil 3 circuits of the same type:

[0082] ,

[0083] in, , , , These represent the current values ​​flowing through the circuits of coil 1, coil 2, coil 2', and coil 3, respectively.

[0084] Similarly, the circuits of coil 3', coil 4, coil 4', and coil 5 need to satisfy the following resonance and decoupling conditions:

[0085] ,

[0086] in, , , , These represent the current values ​​flowing through the circuits of coil 3', coil 4, coil 4', and coil 5, respectively.

[0087] The circuits of coil 5' and coil 6 need to satisfy the following resonance condition:

[0088] ,

[0089] Using the reflection impedance model to model and analyze the system, the reflection impedance of each loop can be obtained from the controlled source and T-shaped equivalent circuit in Figure 5:

[0090] ,

[0091] The " / / " symbol indicates that two loads are connected in parallel. Therefore:

[0092] ,

[0093] ,

[0094] Combining formulas Further derivation yields the expression for the current flowing through each coil circuit as follows:

[0095] .

[0096] Based on the circuit relationships in the controlled source and T-type equivalent circuit diagram in Figure 5, the equivalent load at each relay node is... , , , The corresponding output voltage , , , can be used as a formula The currents in each coil circuit are expressed as follows:

[0097] ,

[0098] Formula Substitute into the formula The expression for the output voltage at each load at each relay node can be obtained as follows:

[0099] ,

[0100] From the formula As can be seen, the output voltage across all loads depends only on the mutual inductance parameters and the input voltage. The multi-stage WPT magnetic coupling mechanism and system with full relay node output provided by this invention can achieve a constant voltage output effect at each relay node location that is independent of the load, as it is independent of the load.

[0101] For Level 1 and Level 3 relay node networks, according to the formula... It can be seen that by configuring appropriate parallel capacitors... and The circuit parameters can change the equivalent mutual inductance. and The value of this value is used to adjust the output voltage of the loads at the first-level and third-level relay node networks. Assume the target output voltage values ​​for the loads at both the first-level and third-level relay nodes are... Then the required parallel capacitor and It should be:

[0102]

[0103] That is, for a relay node network of level m where m is an odd number, in order to achieve the target load output value... Required parallel capacitor The calculation formula is:

[0104]

[0105] here, This represents the mutual inductance between the outer coil of the m-th level relay node network and the inner coil of the preceding level node network, as measured in actual measurements. When m=1, The mutual inductance between the outer coil of the first-level relay node network and the coil of the transmitting node network. .

[0106] For the output voltage at even-numbered relay nodes, the mutual inductance between the outer coil of the relay node and the outer coil of the adjacent relay node (which is a ring structure) can be changed by altering the number of turns of the outer coil in that relay node, thereby achieving the purpose of output voltage gain adjustment.

[0107] Based on the designed multi-stage magnetic coupling mechanism and system with full repeater node output, the parameters of each stage coil are measured using an impedance analyzer, including the coil's self-inductance, mutual inductance between coils, and parasitic resistance. Finally, the circuit parameters, such as the required series compensation capacitor size for each coil, are determined. The solution flowchart is shown in Figure 6. The specific circuit parameter solution steps include:

[0108] S1. Initialize the system's DC input voltage. System operating frequency Each DC load resistor System parameters, set target values ​​for load output voltage of each relay node. ;

[0109] S2. Using Maxwell finite element simulation software, construct a three-dimensional model of the designed magnetic coupling mechanism with full relay node output, and calculate the target value of the load output voltage. The number of turns required for the outer coils (coil 3 and coil 5) in even-level relay nodes is determined by scanning parameters.

[0110] S3. Simulate and measure the coil parameters, including coil self-inductance, mutual inductance, and internal resistance. Substitute the known system parameters into the reflection impedance expression (formula (9)) and the current expression (formula (12)) of each coil loop to obtain the current value of each coil loop.

[0111] S4. Substituting the known and measured system parameters into the circuit parallel capacitance expression (Formula (15)), the circuit parallel capacitance in odd-level relay nodes can be calculated. and ).

[0112] S5. Substitute the coil current and parallel capacitance values ​​obtained from the above steps back to the same type of coil resonance and decoupling conditions (Formula (6), Formula (7) and Formula (8)) to finally calculate the size of the series compensation capacitor required for each circuit.

[0113] To verify the effectiveness of the multi-stage WPT magnetic coupling mechanism and system with full relay node output provided by this invention, numerical simulation verification is performed using the 6-stage WPT system shown in Figure 1. The parameters of the 6-stage WPT system, including DC input voltage, system operating frequency, target load output voltage, coil self-inductance, mutual inductance, coil parasitic resistance, and DC load resistance, are shown in Table 1.

[0114] Table 1 System Parameters

[0115]

[0116] According to the solution process shown in Figure 6, substitute the system parameters in Table 1 into formulas (9) and (12) to obtain the inverter's output voltage. Using the phase as a reference phase, the effective values ​​of the current flowing through each coil circuit are calculated as follows: , , , , , , , , , The current in each coil , , , , , , , , , The waveforms and phases are shown in Figures 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16, respectively. Based on step S4, the parallel capacitance of the circuit can be calculated. and Finally, in step S5, the obtained coil currents and parallel capacitance values ​​are substituted back into formulas (6), (7), and (8) to calculate the required series compensation capacitances for each circuit. , , , , , , , , Under the configured circuit parameters, the output voltage of each relay node is 5V.

[0117] To verify that all loads at all relay nodes possess constant output characteristics and independent characteristics, the output voltage changes of each load were observed by changing the value of one load while keeping the other loads constant. Figure 17 shows the loads at the first-level relay node. The resistance varies within the range of 50Ω to 400Ω, while other loads... , , When both are equal to 100Ω, the output voltage , , , The changes can be seen in the load. The output voltage on the relay gradually increases from 4.5V to around 5.25V, while the output voltage on other loads stabilizes from 5.2V to around 4.95V. Due to the parasitic resistance of the coil, there is a certain deviation between the output voltage of each load and the target output voltage value. However, as the load resistance gradually increases, the output voltage of all loads at the relay nodes reaches a stable value.

[0118] Figure 18 shows the load at the second-level relay node. The resistance varies within the range of 50Ω to 400Ω, while other loads... , , When both are equal to 100Ω, the output voltage , , , The changes can be seen in the load. The output voltage gradually increases from 4.95V, eventually stabilizing at around 5V, and the load... and Output voltage and load The output voltage is basically the same for the load. The output voltage at the relay node drops from 5.18V to 4.9V, and the maximum deviation between the load output voltage at the relay node and the target value of the load output voltage is <5%.

[0119] When the load at the level 3 relay node The resistance varies within the range of 50Ω to 400Ω, while other loads... , , When both are equal to 100Ω, the output voltage , , , The changes are shown in Figure 19. When the load at the fourth-level relay node... The resistance varies within the range of 50Ω to 400Ω, while other loads... , , When both are equal to 100Ω, the output voltage , , , The changes are shown in Figure 20. It can be seen that for the load changes shown in Figures 19 and 20, the changes in each output voltage are basically consistent with the results obtained in Figure 18.

[0120] Simulation results verify that the system can achieve the target output voltage at all relay nodes and has good load independence and output stability.

[0121] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A multi-stage WPT magnetic coupling mechanism with full repeater node output, characterized in that: It includes transmitting nodes, N-2 level relay nodes, and receiving nodes arranged in order of energy transmission direction, where N≥3; the relay nodes are composed of coaxial nested outer and inner coils connected in series; the coil structures used by the transmitting nodes, receiving nodes, outer coils, and inner coils are toroidal coils wound in a planar spiral manner or double semi-circular toroidal coils, and energy is transmitted through coil coupling of the same structural type between adjacent nodes, while coils of different structural types achieve magnetic circuit decoupling; the double semi-circular toroidal coil is composed of two semi-circular toroidal coils with opposite winding directions, placed coplanarly, and whose straight edges are connected to form a complete circle connected in series, and two magnetic fields with opposite polarization directions are generated when current flows through the two semi-circular toroidal coils.

2. The multi-stage WPT magnetic coupling mechanism with full relay node output according to claim 1, characterized in that: The transmitting node uses the loop coil; the relay node uses any one of the following: a first type of combined coil, a second type of combined coil, a third type of combined coil, and a fourth type of combined coil, and adjacent relay nodes use different combined coils. The outer and inner coils of the first type of combined coil are both loop coils; the outer coil of the second type of combined coil is a loop coil and the inner coil is a double semi-circular loop coil; the outer and inner coils of the third type of combined coil are both double semi-circular loop coils; and the outer coil of the fourth type of combined coil is a double semi-circular loop coil and the inner coil is a loop coil. The coil type of the receiving node is consistent with the inner coil type of the last-level relay node.

3. The multi-stage WPT magnetic coupling mechanism with full relay node output according to claim 2, characterized in that: N-2 level relay nodes are arranged cyclically along the energy transmission direction according to either a first arrangement or a second arrangement. The first arrangement is in the order of the first type of combined coil, the second type of combined coil, the third type of combined coil, and the fourth type of combined coil. The second arrangement is in the order of the fourth type of combined coil, the third type of combined coil, the second type of combined coil, and the first type of combined coil.

4. A multi-level WPT system with full relay node output, characterized in that: It includes a high-frequency inverter network, a transmitter node network, N-2 relay node networks, a receiver node network, and N-1 identical rectifier networks that connect the N-2 relay node networks and the receiver node networks one-to-one. The transmitter node network, the N-2 relay node networks, and the receiver node network adopt the multi-stage WPT magnetic coupling mechanism with full relay node output as described in any one of claims 1 to 3.

5. The multi-level WPT system with full relay node output according to claim 4, characterized in that: The m-th level repeater node network includes two branches: an outer coil branch and an inner coil branch, where m = 1, 2, ..., N-2. If the m-th level repeater node network uses either a first-type or a third-type combined coil, then the outer coil branch includes the self-inductance of the series-connected outer coil (m+1). Parasitic resistance With compensation capacitor The inner coil branch includes the self-inductance of the inner coil (m+1)' connected in series. Parasitic resistance Compensation capacitor and the equivalent input resistance of the load derived from the rectifier network. Furthermore, a capacitor is connected in parallel between the outer coil branch and the inner coil branch. If the m-th level relay node network uses a second-type or fourth-type combined coil, then the outer coil branch includes the self-inductance of the series-connected outer coils (m+1). Parasitic resistance With compensation capacitor The inner coil branch includes the self-inductance of the inner coil (m+1)' connected in series. Parasitic resistance and compensation capacitors Furthermore, the equivalent input resistance of the load, which is equivalent to the load network of this stage, is connected in parallel between the outer coil branch and the inner coil branch. 。 6. The multi-level WPT system with full relay node output according to claim 5, characterized in that: The transmitting node network includes the self-inductance of coil 1 connected in series. Parasitic resistance and the series compensation capacitor of the circuit The receiving node network includes the self-inductance of a series-connected coil N. Parasitic resistance Series compensation capacitor and the equivalent input resistance of the load derived from the rectifier network of this stage. 。 7. The multi-level WPT system with full relay node output according to claim 6, characterized in that: For a relay node network of the m-th stage using either a first-type or third-type combined coil, the mutual inductance between its inner and outer coils... ， Indicates the actual measured mutual inductance. This is the system's operating angular frequency.

8. The multi-level WPT system with full relay node output according to claim 7, characterized in that: Based on coupling theory, coil circuits of the same type of coil structure need to meet resonance and decoupling conditions.

9. The multi-level WPT system with full relay node output according to claim 8, characterized in that: For a relay node network of level m where m is odd, in order to achieve the target load output value Required parallel capacitor ， This represents the effective value of the AC voltage output by the high-frequency inverter. This represents the mutual inductance between the outer coil of the m-th level relay node network and the inner coil of the preceding level node network, as measured in actual measurements. When m=1, The mutual inductance between the outer coil of the first-level relay node network and the coil of the transmitting node network. 。 10. The multi-level WPT system with full relay node output according to claim 9, characterized in that, The parameter design process for this system includes: S1, initializing the DC input voltage of the system. System operating frequency Each DC load resistor Set the target value of the load output voltage for each relay node. S2. Using simulation software, build a three-dimensional model of the magnetic coupling mechanism output by the designed full relay node, based on the target value of the load output voltage. S3. Determine the required number of turns of the outer coil in the even-numbered relay node by scanning parameters; S4. Simulate and measure the coil parameters, including coil self-inductance, mutual inductance, and internal resistance. Substitute the known system parameters into the reflection impedance expression of each loop and the current expression flowing through each coil loop to obtain the current value flowing through each coil loop; S5. Substitute the known and measured system parameters into the parallel capacitance expression of the circuit to calculate the parallel capacitance in the odd-numbered relay node; S6. Substitute the coil current and parallel capacitance values ​​obtained in the above steps back into the same type of coil resonance and decoupling conditions to finally calculate the size of the series compensation capacitor required for each loop.

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