A design method of a WPT system based on non-equal coils

Abstract

The application discloses a WPT system design method based on non-equal-size coils, comprising the following steps: constructing a non-equal-size coil UWPT system, which comprises an energy inversion module, an LCC-S resonant compensation network, a non-equal-size natural decoupling coupling mechanism and an energy receiving rectification module; setting a candidate set of overall sizes of a transmitting-side coil, each size candidate value being greater than the overall size of a receiving-side coil; for each size candidate value, changing the number of turns of the transmitting-side coil, selecting the number of turns matched with the self-induction of the receiving-side through finite element simulation to form a candidate set of the number of turns; for each size-turn combination, applying multiple groups of offset working conditions, extracting the self-induction, mutual inductance and eddy current equivalent resistance; calculating anti-offset performance indexes, including the self-induction fluctuation, the coupling coefficient, the transmission efficiency and the input and output power; and selecting the optimal combination and determining the final parameters according to the anti-offset performance priority principle; and the application improves the anti-offset performance and the transmission efficiency of the system under horizontal and rotational offsets through size-turn collaborative optimization.

Description

Technical Field

[0001] This invention relates to the field of wireless power transfer technology, and in particular to a design method for a WPT system based on non-uniform coils. Background Technology

[0002] Oceans cover 71% of the Earth's surface and are rich in mineral and biological resources, making them a crucial strategic space that countries are vying for. Underwater wireless power transfer (UWPT) technology allows for power transfer between the transmitter and receiver without physical contact, avoiding insulation problems caused by underwater wet plugging and unplugging. It offers advantages such as safety, convenience, and ease of maintenance, and holds great promise for the exploration, development, and application of marine resources. However, in practical applications, UWPT systems are loosely coupled power transfer structures, making the transmitter and receiver susceptible to misalignment due to external environmental influences. Horizontal, rotational, or combined misalignments can cause drastic fluctuations in mutual inductance parameters, leading to significant drops in system output voltage and transmission efficiency. In severe cases, this can even cause the system to lose resonance, malfunction, or damage power devices.

[0003] Improving the system's drift resistance is key to expanding the application scenarios of WPT (Wide-to-the-Field) transmission. In WPT systems, the magnetic coupling mechanism is the core component determining the system's transmission performance and drift resistance. In terms of coupling mechanism design, the main approach is to optimize the coil structure to generate a relatively uniform magnetic field, thereby improving the system's drift resistance. Examples include asymmetric circular coil structures and double-D (DD) coils. Besides single structures, there are also multi-coil orthogonal topologies, such as double-D quadrature (DDQ) coil structures and quadruple-D quadrature Pad (QDQP) coil structures. Furthermore, there are multi-mode compatible coil topologies, such as double-orthogonal DD coil (DDDQ) structures. Existing technologies often optimize the transmitter-side coil structure to form a relatively uniform magnetic field, thereby maintaining the stability of the coupling magnetic flux of the receiver-side coil during drift events and preserving system transmission performance. A common practice is to increase the size of the transmitter-side coil to expand the magnetic field coverage and improve tolerance to horizontal and rotational drift. However, increasing the size of the coil will significantly increase its self-inductance, causing a mismatch between the self-inductance at the transmitting and receiving ends. This leads to increased voltage stress on the power devices and disrupts the system resonance condition, ultimately affecting transmission efficiency and operational reliability.

[0004] Existing research shows that, in the design of coupling mechanisms, related studies mainly focus on optimizing coil structures to generate a relatively uniform magnetic field, thereby improving the system's resistance to deflection. However, current coil topology designs still face three core contradictions: 1. Single-dimensional optimization is contradictory. Most structures can only specifically improve the anti-offset performance in a single horizontal or rotational direction, making it difficult to adapt to multi-directional offsets. 2. There is a contradiction between decoupling performance and system complexity. Traditional decoupling solutions often rely on additional filtering components or complex control algorithms, which sacrifices energy transmission efficiency and increases hardware costs and debugging difficulty. 3. The contradiction between anti-offset range and engineering practicality: high-performance solutions often rely on large-size coil design or precision control strategies, which leads to increased coil winding complexity and volume redundancy, making it difficult to meet the installation and cost requirements in practical applications. Summary of the Invention

[0005] This invention provides a WPT system design method based on non-uniform coils to overcome the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A design method for a WPT system based on non-uniform coils, applied to marine environments, includes: S1: Construct a UWPT system with non-uniform coils. The UWPT system includes an energy inverter module, an LCC-S resonant compensation network, a non-uniform natural decoupling coupling mechanism, and an energy receiving and rectifying module. The non-uniform natural decoupling coupling mechanism includes a transmitting coil and a receiving coil with a reconfigured coil structure using natural decoupling. S2: Within a preset size range, a candidate set of the overall size of the transmitting coil is set, and each candidate size value is greater than the overall size of the receiving coil; the size is the equivalent outer envelope size; S3: For each size candidate value in the overall size candidate set, change the number of turns of the transmitting coil, extract the self-inductance of the transmitting coil under different numbers of turns through finite element simulation, and filter out the number of turns that makes the difference between the self-inductance of the transmitting coil and the self-inductance of the receiving coil not exceed a preset threshold, thus forming a number of turns candidate set corresponding to the size candidate value. S4: For each size-turns combination consisting of the overall size candidate value and the number of turns in the corresponding turns candidate set, establish a three-dimensional finite element simulation model, apply multiple offset conditions including different horizontal offset distances and different rotational offset angles to the receiving coil, and extract the offset condition coefficients under each offset condition. The offset condition coefficients include the self-inductance of the transmitting coil, the self-inductance of the receiving coil, the mutual inductance between the transmitting coil and the receiving coil, and the eddy current equivalent resistance caused by eddy current loss generated by the UWPT system in the seawater medium. S5: Based on multiple sets of offset operating parameters, calculate the anti-offset performance index for each size-turns combination; the performance index includes the average fluctuation of the transmitting coil, the average fluctuation of the receiving self-inductance, the coupling coefficient, the transmission efficiency, and the input and output power; S6: Based on the principle of prioritizing anti-migration performance, the optimal combination is selected and the final parameters are determined based on the performance indicators under multiple misalignment conditions.

[0007] Furthermore, the energy inverter module includes a DC power supply and a full-bridge inverter circuit, used to convert the DC power supplied by the DC power supply into high-frequency AC power and provide excitation energy for the system; The LCC-S resonant compensation network includes a primary-side LCC compensation network and a secondary-side series compensation network. The primary-side LCC compensation network and the transmitting-side coil form an LCC resonant topology, which is used to excite the transmitting-side coil to generate a constant high-frequency AC current based on the high-frequency AC current output by the energy inverter module, thereby reducing reactive power loss. The secondary-side series compensation network and the receiving-side coil form a series resonant topology, which is used to convert the high-frequency AC voltage induced by the receiving-side coil into a high-frequency AC current in the secondary circuit, thereby improving energy transmission efficiency. The transmitting coil is used to receive the high-frequency alternating current provided by the primary-side LCC compensation network and generate an alternating magnetic field of the same frequency in the surrounding space; the receiving coil is used to induce a high-frequency alternating voltage at both ends of the receiving coil based on the alternating magnetic field through electromagnetic induction, and to achieve natural decoupling by reconstructing the coil structure to cancel out the positive and negative coupling between adjacent sub-coils. The energy receiving and rectifying module includes a full-bridge rectifier circuit and a load, used to rectify the high-frequency AC current converted by the secondary-side series compensation network into DC voltage and provide DC output to the load. The output terminal of the energy inverter module is connected to the input terminal of the primary-side LCC compensation network, and the output terminal of the primary-side LCC compensation network is connected to the input terminal of the transmitting-side coil; the output terminal of the receiving-side coil is connected to the input terminal of the secondary-side series compensation network, and the output terminal of the secondary-side series compensation network is connected to the input terminal of the energy receiving rectifier module.

[0008] Furthermore, the transmitting coil L P Including the first transmitter coil L connected in series T1 Second transmitting sub-coil L T2 Third transmitting sub-coil L T3 and the fourth transmitting sub-coil L T4 ; Wherein, the first transmitting sub-coil L T1 and the fourth transmitting sub-coil L T4They are respectively connected to the output terminals of the primary-side LCC compensation network.

[0009] Furthermore, the receiving-side coil employing the naturally decoupled reconfigured coil structure includes a first array coil L. R10 Second array coil L R20 The first array coil L R10 Including the first receiving sub-coil L connected in series R1 and the fourth receiver coil L R4 Second array coil L R20 Including the second receiving sub-coil L R2 and the third receiving sub-coil L R3 ; Wherein, the first receiving sub-coil L R1 and the fourth receiver coil L R4 They are respectively connected to the input terminals of the secondary-side series compensation network.

[0010] Furthermore, based on multiple sets of offset condition parameters, the offset resistance performance index for each size-turns combination is calculated, including: Calculate the fluctuation of the self-inductance of the transmitting coil and the receiving coil under all offset conditions, and calculate the average value of the fluctuation of the transmitting coil and the receiving coil respectively; the fluctuation is the difference between the self-inductance value when there is no offset and the self-inductance value when there is an offset. Calculate the average fluctuation of the coupling coefficient under all offset conditions, where the expression for the coupling coefficient is:

[0011] in, The coupling coefficient is... For the mutual inductance of the transmitting coil and the receiving coil, For the self-inductance of the transmitting coil, The self-inductance of the transmitting coil; The formulas for calculating transmission efficiency and input / output power are as follows:

[0012] in, For output power, For input power, For transmission efficiency, This is the input current of the primary-side LCC compensation network. and The branch currents of the first array coil and the second array coil are denoted as . and This is the equivalent resistance of the full-bridge rectifier circuit; and The equivalent resistance of the eddy current; This is the excitation voltage output by the full-bridge inverter circuit. For angular frequency operators, and For the mutual inductance between the transmitting coil and the two array coils, This refers to the parallel compensation capacitor in the primary-side LCC compensation network.

[0013] Furthermore, based on the principle of prioritizing anti-migration performance, the optimal combination of performance indicators under multiple misalignment conditions is selected, and the final parameters are determined, including: For all size-turns combinations, performance metrics under multiple offset conditions were selected in the following order: First priority: compare the average self-inductance fluctuation of the transmitting coil with the average self-inductance fluctuation of the receiving coil, and select size-turns combinations in which both are less than a preset threshold. The second priority is to select size-turn combinations from the size-turn combinations selected by the first priority that have an average coupling coefficient fluctuation of less than a preset threshold. The third priority is to select size-turns combinations that have an average transmission efficiency greater than a preset threshold under offset conditions from the size-turns combinations selected by the second priority. The fourth priority is to select the size-turns combination with the highest average input power and output power from the size-turns combinations selected in the third priority. The fifth priority is to select the optimal combination of size-turns ratio from the size-turns ratio combinations selected in the fourth priority selection. The emitter coil size and number of turns corresponding to the optimal combination selected in the final screening will be used as the final circuit design parameters.

[0014] Furthermore, the DC power supply in the energy inverter module is connected to the input terminal of the full-bridge inverter circuit, which includes a first switch S1 with an anti-parallel diode, a second switch S2 with an anti-parallel diode, a third switch S3 with an anti-parallel diode, and a fourth switch S4 with an anti-parallel diode. The drain of the first switching transistor S1 with anti-parallel diode is connected to the positive bus of the DC power supply, and the source is connected to the left half-bridge node as one end of the AC output terminal; the gate is connected to the drive control signal. The source of the second switch S2 with anti-parallel diode is connected to the negative bus of the DC power supply, and the drain of the switch S2 with anti-parallel diode is connected to the same node as the source of the first switch S1 with anti-parallel diode, which together serve as one end of the AC output terminal; the gate is connected to the drive control signal. The drain of the third switching transistor S3 with anti-parallel diode is connected to the positive bus of the DC power supply; the source is connected to the right half-bridge node, serving as the other end of the AC output terminal; and the gate is connected to the drive control signal. The source of the fourth switch S4 with anti-parallel diode is connected to the negative bus of the DC power supply; the drain and the source of the third switch S3 with anti-parallel diode are connected to the same node, serving as the other end of the AC output terminal; the gate is connected to the drive control signal.

[0015] Furthermore, the primary-side LCC compensation network includes a first inductor L. f Parallel compensation capacitor C f Second capacitor C p The secondary-side series compensation network includes a second capacitor C. R10 and the third capacitor C R20 ; The first inductor L f One end is connected to the right half-bridge node, and the other end is connected to the parallel compensation capacitor C. f and the first capacitor C p One end is connected to the parallel compensation capacitor C. f The other end is connected to the fourth transmitting sub-coil L T4 One end is connected; the first capacitor C p The other end is connected to the first transmitting sub-coil L T1 One end is connected; The second capacitor C R10 One end is connected to the first receiving sub-coil L R1 One end is connected to the third capacitor C. R20 One end is connected to the second receiving sub-coil L R2 One end is connected.

[0016] Furthermore, the full-bridge rectifier circuit includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, and a fourth capacitor C. s1 and the fifth capacitor C s2 ; The anode of the first diode D1 is connected to the second capacitor C R10 The other end is connected, with the cathode connected to the cathode of the third diode D3; the cathode of the second diode D2 is connected to the anode of the first diode D1, and the anode is connected to the anode of the fourth diode D4; the cathode of the third diode D3 is connected to the fourth capacitor C. s1 One end is connected, and the anode of the third diode D3 is connected to the fourth receiving sub-coil L. R4One end of the diode is connected to the cathode of the fourth diode D4; the cathodes of the fifth diode D5 and the seventh diode D7 are connected, and their anodes are connected to the third capacitor CR. 20 The other end is connected to the cathode of the sixth diode D6; the anode of the sixth diode D6 is connected to the anode of the eighth diode D8; the cathode of the seventh diode D7 is connected to the fifth capacitor C. s2 One end is connected, and the anode is connected to the cathode of the eighth diode D8 and the third receiver coil L, respectively. R3 One end is connected; the anode of the eighth diode D8 is connected to the fifth capacitor C. s2 The other end is connected; Fourth capacitor C s1 One end is connected to the load R L One end is connected to the fifth capacitor C. s2 The other end is connected to the load R L The other end is connected.

[0017] Beneficial effects: This invention provides a WPT system design method based on non-uniform coils, which has the following advantages: 1. The receiving coil adopts a reconfigurable coil structure that can be naturally decoupled. No additional decoupling components are needed; the coil's own structural design suppresses cross-coupling between coils on the same side, achieving natural decoupling. This not only simplifies system complexity but also ensures engineering practicality, significantly enhancing the system's tolerance to rotational and horizontal offsets.

[0018] 2. An improved structural dimension and turns ratio of the transmitting coil was proposed, employing a size-turns co-optimization strategy: while moderately increasing the transmitting coil size to expand the magnetic field coverage, the number of turns was correspondingly reduced. The receiving coil size and turns remained constant, and the transmitting coil was parametrically optimized using its self-inductance as a matching benchmark. Through this co-adjustment, self-inductance fluctuations were minimized, and resonance stability was strengthened, effectively optimizing the magnetic field distribution without sacrificing self-inductance matching. The selected transmitting coil, through optimization of turns and size, achieved advantages such as higher magnetic flux density amplitude, more uniform distribution, and a wider effective range. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A flowchart of a WPT system design method based on non-uniform coils provided by the present invention; Figure 2 A schematic diagram of the UWPT system circuit provided by the present invention; Figure 3 This is a schematic diagram of the coil and magnetic core structure of the transmitting and receiving sides of the system of the present invention; Figure 4 This is a schematic diagram of the non-uniform coil structure of the present invention. Figure 5 This is a schematic diagram of the transmitter-side structural dimensions of the present invention and a schematic diagram of the transmitter-side structural dimensions of a conventional system; Figure 6 This is a schematic diagram of oscilloscope waveforms when the receiving coils of different structures are horizontally offset by 200mm according to an embodiment of the present invention. Figure 7 This is a schematic diagram of the efficiency variation with horizontal offset in an embodiment of the present invention; Figure 8 This is a schematic diagram of oscilloscope waveforms when the receiving coils of different structures are rotated and offset by 45 degrees according to embodiments of the present invention. Figure 9 This is a schematic diagram of the oscilloscope waveform of the structure proposed in this invention when the receiving coil is rotated and offset by 90 degrees according to an embodiment of this invention; Figure 10 This is a schematic diagram of the output power variation with rotational offset in an embodiment of the present invention; Figure 11 This is a schematic diagram of the efficiency variation with rotational offset in an embodiment of the present invention; Figure 12 This is a schematic diagram comparing the coupling coefficients of a conventional system and the structure of this invention under horizontal offset conditions according to an embodiment of the invention; Figure 13 This is a schematic diagram comparing the self-inductance of a conventional system and the structure of the present invention under horizontal offset conditions according to an embodiment of the present invention; Figure 14 This is a schematic diagram comparing the coupling coefficients of a conventional system and the structure of this invention under rotational offset conditions according to an embodiment of the invention; Figure 15 This is a schematic diagram comparing the changes in the self-inductance of the transmitting coil before and after optimization under the rotational offset condition in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This embodiment provides a WPT system design method based on non-uniform coils, such as... Figure 1 As shown, it includes: S1: Construct an UWPT (Underwater Wireless Power Transfer) system with non-uniform coils. The UWPT system includes an energy inverter module, an LCC-S resonant compensation network, a non-uniform natural decoupling coupling mechanism, and an energy receiving and rectifying module. The non-uniform natural decoupling coupling mechanism includes a transmitting coil and a receiving coil with a reconfigured coil structure using natural decoupling. S2: Within a preset size range, a candidate set of the overall size of the transmitting coil is set, and each candidate size value is greater than the overall size of the receiving coil; the size is the equivalent outer envelope size; S3: For each size candidate value in the overall size candidate set, change the number of turns of the transmitting coil, extract the self-inductance of the transmitting coil under different numbers of turns through finite element simulation, and filter out the number of turns that makes the difference between the self-inductance of the transmitting coil and the self-inductance of the receiving coil not exceed a preset threshold, thus forming a number of turns candidate set corresponding to the size candidate value. S4: For each size-turns combination consisting of the overall size candidate value and the number of turns in the corresponding turn number candidate set, a three-dimensional finite element simulation model is established. Multiple offset conditions including different horizontal offset distances and different rotational offset angles are applied to the receiving coil. The offset condition coefficients under each offset condition are extracted. The offset condition coefficients include the self-inductance of the transmitting coil, the self-inductance of the receiving coil, the mutual inductance between the transmitting coil and the receiving coil, and the eddy current equivalent resistance caused by eddy current loss generated by the UWPT system in the seawater medium. S5: Based on multiple sets of offset operating parameters, calculate the anti-offset performance index for each size-turns combination; the performance index includes the average fluctuation of the transmitting coil, the average fluctuation of the receiving self-inductance, the coupling coefficient, the transmission efficiency, and the input and output power; S6: Based on the principle of prioritizing anti-migration performance, the optimal combination is selected and the final parameters are determined based on the performance indicators under multiple misalignment conditions.

[0023] In a specific embodiment, a UWPT system with non-uniform coils is constructed. The UWPT system includes an energy inverter module, an LCC-S resonant compensation network, a non-uniform natural decoupling mechanism, and an energy receiving and rectifying module. The non-uniform natural decoupling mechanism includes a transmitting coil and a receiving coil with a naturally decoupled reconfigured coil structure. The energy inverter module includes a DC power supply and a full-bridge inverter circuit, which is used to convert the DC power supplied by the DC power supply into high-frequency AC power and provide excitation energy for the system. The LCC-S resonant compensation network includes a primary-side LCC compensation network and a secondary-side series compensation network. The primary-side LCC compensation network and the transmitting-side coil form an LCC resonant topology, which is used to excite the transmitting-side coil to generate a constant high-frequency AC current based on the high-frequency AC current output by the energy inverter module, thereby reducing reactive power loss. The secondary-side series compensation network and the receiving-side coil form a series resonant topology, which is used to convert the high-frequency AC voltage induced by the receiving-side coil into a high-frequency AC current in the secondary circuit, thereby improving energy transmission efficiency. The transmitting coil is used to receive the high-frequency alternating current provided by the primary-side LCC compensation network and generate an alternating magnetic field of the same frequency in the surrounding space; the receiving coil is used to induce a high-frequency alternating voltage at both ends of the receiving coil based on the alternating magnetic field through electromagnetic induction, and to achieve natural decoupling by reconstructing the coil structure to cancel out the positive and negative coupling between adjacent sub-coils. The energy receiving and rectifying module includes a full-bridge rectifier circuit and a load, used to rectify the high-frequency AC current converted by the secondary-side series compensation network into DC voltage and provide DC output to the load. The output terminal of the energy inverter module is connected to the input terminal of the primary-side LCC compensation network, and the output terminal of the primary-side LCC compensation network is connected to the input terminal of the transmitting coil; the output terminal of the receiving coil is connected to the input terminal of the secondary-side series compensation network, and the output terminal of the secondary-side series compensation network is connected to the input terminal of the energy receiving rectifier module. like Figure 2 As shown, the specific connection is as follows: In the energy inverter module, the DC power supply is connected to the input terminal of the full-bridge inverter circuit. The full-bridge inverter circuit includes a first switch S1 with an anti-parallel diode, a second switch S2 with an anti-parallel diode, a third switch S3 with an anti-parallel diode, and a fourth switch S4 with an anti-parallel diode. The drain of the first switching transistor S1 with anti-parallel diode is connected to the positive bus of the DC power supply, and the source is connected to the left half-bridge node as one end of the AC output terminal; the gate is connected to the drive control signal. The source of the second switch S2 with anti-parallel diode is connected to the negative bus of the DC power supply, and the drain of the switch S2 with anti-parallel diode is connected to the same node as the source of the first switch S1 with anti-parallel diode, which together serve as one end of the AC output terminal; the gate is connected to the drive control signal. The drain of the third switching transistor S3 with anti-parallel diode is connected to the positive bus of the DC power supply; the source is connected to the right half-bridge node, serving as the other end of the AC output terminal; and the gate is connected to the drive control signal. The source of the fourth switch S4 with anti-parallel diode is connected to the negative bus of the DC power supply; the drain of the switch S4 with anti-parallel diode is connected to the same node as the source of the third switch S3 with anti-parallel diode, which together serve as the other end of the AC output terminal; the gate is connected to the drive control signal. The primary-side LCC compensation network includes a first inductor L f Parallel compensation capacitor C f Second capacitor C p The secondary-side series compensation network includes a second capacitor C. R10 and the third capacitor C R20 ; The first inductor L f One end is connected to the right half-bridge node, and the other end is connected to the parallel compensation capacitor C. f and the first capacitor C p One end is connected to the parallel compensation capacitor C. f The other end is connected to the fourth transmitting sub-coil L T4 One end is connected; the first capacitor C p The other end is connected to the first transmitting sub-coil L T1 One end is connected; The second capacitor C R10 One end is connected to the first receiving sub-coil L R1 One end is connected to the third capacitor C. R20 One end is connected to the second receiving sub-coil L R2 One end is connected; The transmitting coil L P Including the first transmitter coil L connected in series T1 Second transmitting sub-coil L T2 Third transmitting sub-coil L T3 and the fourth transmitting sub-coil L T4 ; Wherein, the first transmitting sub-coil L T1 and the fourth transmitting sub-coil L T4 Each is connected to the output of the primary-side LCC compensation network; The receiving coil of the reconstructed coil structure employing natural decoupling includes a first array coil L. R10 Second array coil L R20 The first array coil L R10 Including the first receiving sub-coil L connected in series R1 and the fourth receiver coil L R4 Second array coil L R20 Including the second receiving sub-coil L R2 and the third receiving sub-coil L R3 ; Wherein, the first receiving sub-coil L R1 and the fourth receiver coil L R4 Each is connected to the input terminal of the secondary-side series compensation network; The full-bridge rectifier circuit includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, and a fourth capacitor C. s1 and the fifth capacitor C s2 ; The anode of the first diode D1 is connected to the second capacitor C R10 The other end is connected, with the cathode connected to the cathode of the third diode D3; the cathode of the second diode D2 is connected to the anode of the first diode D1, and the anode is connected to the anode of the fourth diode D4; the cathode of the third diode D3 is connected to the fourth capacitor C. s1 One end is connected, and the anode of the third diode D3 is connected to the fourth receiving sub-coil L. R4 One end of the diode is connected to the cathode of the fourth diode D4; the cathodes of the fifth diode D5 and the seventh diode D7 are connected, and their anodes are connected to the third capacitor CR. 20 The other end is connected to the cathode of the sixth diode D6; the anode of the sixth diode D6 is connected to the anode of the eighth diode D8; the cathode of the seventh diode D7 is connected to the fifth capacitor C. s2 One end is connected, and the anode is connected to the cathode of the eighth diode D8 and the third receiver coil L, respectively. R3 One end is connected; the anode of the eighth diode D8 is connected to the fifth capacitor C. s2 The other end is connected; Fourth capacitor C s1 One end is connected to the load R L One end is connected to the fifth capacitor C. s2 The other end is connected to the load R L The other end is connected.

[0024] Specifically, the system adopts an LCC-S hybrid compensation topology. The receiving side uses a 2×2 array coil, consisting of four symmetrical sub-coils. Through geometric symmetry and current direction control, the positive and negative couplings of adjacent coils are canceled out, achieving natural decoupling without the need for any additional decoupling components. Due to L… R1 (L1), L R2 (L2), L R3 (L3) and L R4 (L4) Geometrically symmetrical, with consistent dimensions, and current direction according to Figure 3 As shown in the configuration, the two receiving subunits are naturally decoupled, meaning that cross-coupling between coils on the same side can be suppressed without additional components. Therefore, the self-inductance of the receiving coil is:

[0025] The system operating frequency is set to 85kHz. The 2×2 natural decoupling coil structure on the receiving side ensures that the size, number of turns, and wire diameter of each sub-coil are completely consistent, and they are arranged in a square with equal spacing in the plane. A cross-series combination method is adopted to utilize the mutual cancellation effect of positive and negative coupling between adjacent sub-coils to achieve natural decoupling between the two receiving units without the need for additional decoupling components or complex control algorithms. The formula for calculating the self-inductance of the receiving coil is derived, and it is verified that under natural decoupling conditions, the self-inductance of the receiving unit is determined only by the self-inductance of a single sub-coil, eliminating the additional self-inductance increment caused by cross coupling and ensuring the stability of the inductance parameters on the receiving side.

[0026] In a specific embodiment, within a preset size range, a candidate set of overall sizes for the transmitting coil is set, and each size value is larger than the overall size of the receiving coil. The design principle prioritizes anti-offset performance while also considering self-inductance matching. While keeping the receiving coil parameters constant, the total self-inductance of the receiving coil is used as the matching benchmark for parameter optimization of the transmitting coil. A collaborative optimization strategy of increasing size and reducing the number of turns is adopted to expand the magnetic field coverage while maintaining the consistency of self-inductance between the transmitting and receiving coils. Finite element simulation is used to compare the magnetic flux density distribution generated by the transmitting coil on the receiving side plane before and after optimization. Therefore, within the designable size range, this invention sets different dimensions for subsequent turns matching.

[0027] In a specific embodiment, for each candidate size value in the overall size candidate set, the number of turns of the transmitting coil is changed, and the self-inductance of the transmitting coil under different numbers of turns is extracted by finite element simulation. The scheme for selecting the number of turns such that the difference between the self-inductance of the transmitting coil and the self-inductance of the receiving coil does not exceed a preset threshold, thus forming the turn number candidate set corresponding to the size candidate value, is as follows: The transmitting coil is larger than the receiving coil to expand the magnetic field coverage area; such as Figure 3 As shown, Figure 3This is a schematic diagram of the coil structure proposed in this invention. This invention establishes a design principle prioritizing anti-offset performance while also considering self-inductance matching, and proposes a size-turns co-optimization strategy: while appropriately increasing the size of the transmitting coil to expand the magnetic field coverage, its number of turns is correspondingly reduced. Through this co-adjustment, the magnetic field distribution can be effectively optimized without sacrificing self-inductance matching, ensuring that the self-inductance of the transmitting coil and the receiving coil are matched, avoiding resonance detuning and device overstress. Using a co-optimization strategy of increasing size and reducing turns, the magnetic flux density distribution generated by the transmitting coil on the receiving side plane before and after optimization is compared through finite element simulation. Simultaneously, to ensure the principle of single-variable control, all ferrite cores are removed, and simulation is performed only on the hollow coil structure. The self-inductance of the transmitting coil under different turns is extracted, and the number of turns that ensures the difference between the self-inductance of the transmitting coil and the self-inductance of the receiving coil does not exceed a preset threshold is selected, forming a candidate set of turns corresponding to the candidate size value.

[0028] In a specific embodiment, for each size-turns combination consisting of the overall size candidate value and the number of turns in the corresponding turns candidate set, a three-dimensional finite element simulation model is established. Multiple offset conditions, including different horizontal offset distances and different rotational offset angles, are applied to the receiving coil. Offset condition coefficients are extracted for each offset condition. These offset condition coefficients include the self-inductance of the transmitting coil, the self-inductance of the receiving coil, the mutual inductance between the transmitting coil and the receiving coil, and the eddy current equivalent resistance caused by eddy current losses generated by the UWPT system in seawater. like Figure 4 As shown, a three-dimensional Cartesian coordinate system is established (origin at O). The plane containing the transmitting coil (Tx Plane) is located in the XY plane (the gray base plane in the figure), and the receiving coils (Rx coils) are located in an upper spatial plane parallel to the transmitting coil plane. Using the plane containing the receiving coil as the reference plane (Rx plane), the receiving coils are offset along the spatial coordinate axes. Indicates the angle of rotation offset. Indicates the horizontal offset distance; Extract the offset condition coefficients for each set of offset conditions. The offset condition coefficients include the self-inductance of the transmitting coil, the self-inductance of the receiving coil, the mutual inductance between the transmitting coil and the receiving coil, and the eddy current equivalent resistance generated by the UWPT system in seawater medium due to eddy current losses. Specifically, unlike the situation in air, when a wireless power transmission system operates in a seawater environment, the inherent conductivity of the saltwater medium causes different system losses, resulting in eddy current losses and affecting power transmission efficiency. Furthermore, the conductivity of seawater also affects the impedance and magnetic flux of the coil itself, leading to system detuning.

[0029] The eddy current losses introduced by seawater into the UWPT system can be characterized by eddy current loss resistance, which is the equivalent internal resistance caused by the eddy current losses generated by LP in seawater. Since RP and RS include the eddy current losses generated when the system operates in seawater, power transmission is affected by eddy current losses. In the early stages of system design, the finite element method is used to calculate the equivalent internal resistance of the coil introduced by eddy current losses.

[0030] In a specific embodiment, based on multiple sets of offset operating condition parameters, the offset resistance performance index of each size-turns combination is calculated; the performance index includes the average fluctuation of the transmitting coil, the average fluctuation of the receiving self-inductance, the coupling coefficient, the transmission efficiency, and the input-output power. Calculate the fluctuation of the self-inductance of the transmitting coil and the receiving coil under all offset conditions, and calculate the average value of the fluctuation of the transmitting coil and the receiving coil respectively; the fluctuation is the difference between the self-inductance value when there is no offset and the self-inductance value when there is an offset. Calculate the average fluctuation of the coupling coefficient under all offset conditions, where the expression for the coupling coefficient is:

[0031] in, The coupling coefficient is... For the mutual inductance of the transmitting coil and the receiving coil, For the self-inductance of the transmitting coil, The self-inductance of the transmitting coil; The formulas for calculating transmission efficiency and input / output power are as follows:

[0032] in, For output power, For input power, For transmission efficiency, This is the input current of the primary-side LCC compensation network. and The branch currents of the first array coil and the second array coil are denoted as . and This is the equivalent resistance of the full-bridge rectifier circuit; and The equivalent resistance of the eddy current; This is the excitation voltage output by the full-bridge inverter circuit. For angular frequency operators, and The mutual inductance between the transmitting coil and the two array coils, This refers to the parallel compensation capacitor in the primary-side LCC compensation network.

[0033] In a specific embodiment, based on the principle of prioritizing anti-migration performance, the scheme for selecting the optimal combination and determining the final parameters based on performance indicators under multiple misalignment conditions is as follows: For all size-turns combinations, performance metrics under multiple offset conditions were selected in the following order: First priority: compare the average self-inductance fluctuation of the transmitting coil with the average self-inductance fluctuation of the receiving coil, and select size-turns combinations in which both are less than a preset threshold. The second priority is to select size-turn combinations from the size-turn combinations selected by the first priority that have an average coupling coefficient fluctuation of less than a preset threshold. The third priority is to select size-turns combinations that have an average transmission efficiency greater than a preset threshold under offset conditions from the size-turns combinations selected by the second priority. The fourth priority is to select the size-turns combination with the highest average input power and output power from the size-turns combinations selected in the third priority. The fifth priority is to select the optimal combination of size-turns ratio from the size-turns ratio combinations selected in the fourth priority selection. The emitter coil size and number of turns corresponding to the optimal combination selected in the final screening will be used as the final circuit design parameters.

[0034] It should be noted that, initially, the transmitting and receiving coils have the same configuration. Therefore, changing only the number of turns or size has a limited impact on the self-inductance. In the aforementioned priority determination process, there must exist combinations that satisfy all the set thresholds.

[0035] Figure 5 In the diagram, (a) represents the transmitting side used in this invention, and (b) represents the transmitting side of a conventional system. Both transmitting side coils adopt a 2×2 sub-coil array structure. After optimization, the overall size of the transmitting side coil used in this invention is 550mm×550mm, the size of the sub-coil unit is 275mm×275mm, and the number of turns is 10. The larger coil size can improve the spatial diffusion capability of the magnetic field and expand the effective range of the magnetic flux density.

[0036] To verify the effectiveness of this invention, an experimental platform was built for testing a WPT system based on the LCC-S topology. It mainly consists of a DC power supply module, a single-phase bridge inverter and drive power supply, a DSP control unit (TMS320F28335), primary and secondary side compensation networks, transmitting and receiving coils, an uncontrolled rectifier bridge module, a load resistor box, and an auxiliary power supply. The system operates at a frequency of 85kHz.

[0037] Figure 6Comparative oscilloscope waveforms are presented between the conventional structure and the structure proposed in this invention when the transmitting and receiving coils are laterally misaligned by 200 mm. Figure 5 As shown in (a), for the traditional structure, the oscilloscope displays the output DC voltage V. out The voltage is 41.5V, and the output current is I. out Approximately 1.32A, corresponding to an output power P out Approximately 55W. Using the formula, the transmission efficiency of this structure under these conditions is calculated to be approximately 88%. For example... Figure 5 As shown in (b), for the structure proposed in this invention, the oscilloscope displays the output DC voltage V. out The voltage is 42.2V, and the output current I is... out Approximately 1.4A, corresponding to an output power P out It is approximately 59W. Calculations show that the power transmission efficiency is approximately 91%, an improvement of about 3% compared to the traditional structure.

[0038] Under horizontal offset conditions, multiple sets of efficiency comparison experiments were conducted between the structure proposed in this invention and a conventional system. The efficiency variation patterns are as follows: Figure 7 As shown in the figure, the horizontal axis represents Lateral Misalignment (mm), and the vertical axis represents efficiency. Efficiency Conventional represents the efficiency of the conventional system, and Efficiency Proposed represents the efficiency of the present invention. The results show that within the misalignment range of 0-200 mm, the efficiency of the structure of the present invention consistently remains above 91%, demonstrating strong anti-misalignment performance. In contrast, the efficiency of the conventional system shows a continuous decreasing trend with increasing misalignment, and the decrease is significantly greater. Overall, the improved structure exhibits a slower efficiency decay rate within the horizontal misalignment range, fully demonstrating its higher stability and robustness under horizontal misalignment conditions.

[0039] Experimental verification of the anti-rotational offset performance of non-equivalent natural decoupled mechanisms; Figure 8 Comparison of oscilloscope waveforms between the conventional structure and the structure proposed in this invention is given when the transmitting coil is rotated and offset by 45°. Figure 8 As shown in (a), for a conventional structure, the oscilloscope output DC voltage V out Approximately 36V, output current I out Approximately 1.44A, corresponding to an output power P out It is approximately 52W. Using the formula, the transmission efficiency of this structure under these conditions is calculated to be approximately 84%. For example... Figure 8 As shown in (b), for the structure proposed in this invention, the oscilloscope outputs a DC voltage V. out 38V, output current I outApproximately 1.65A, corresponding to an output power P out It is approximately 63W. Calculations show that the power transfer efficiency is approximately 91.4%, an improvement of about 7.4% compared to conventional structures.

[0040] Figure 9 The oscilloscope waveform of the structure proposed in this invention is shown when the receiving coil is misaligned by 90°. Under this condition, the oscilloscope displays the output DC voltage V. out 55V, output current I out Approximately 2.18A, corresponding to an output power P out It is 120W. Calculations show a power transfer efficiency of approximately 94%.

[0041] Figure 10 The figure illustrates the output power variation of the system within a rotational offset range of 0–360°. In the figure, the horizontal axis represents Rotational Misalignment (°), and the vertical axis represents output power. The power variation for the conventional structure (Power Conventional) and the proposed structure (Power Proposed) are shown. Experimental results reveal differences in energy transfer between the conventional and proposed structures at different rotational angles. The conventional structure exhibits significant periodic power fluctuations: peaking near 0°, 180°, and 360°, and dropping almost to zero at 90° and 270°. This indicates that its coupling strength is highly sensitive to the relative angle of the coil; once the closed path of the coil magnetic flux is disrupted, the power decreases sharply. In contrast, the proposed structure maintains high output power across the entire angle range, even at positions where the conventional system is completely mismatched, such as 90° and 270°, maintaining approximately 120W. Overall, the improved structure weakens the influence of rotational angle on magnetic coupling, significantly reducing the fluctuation amplitude of the output power curve. This verifies its stronger robustness and symmetry under rotational offset conditions, thus achieving more stable energy transfer performance.

[0042] Figure 11 The figure illustrates the power transmission efficiency variations of conventional and proposed structures under rotational offset conditions of 0–360°. The vertical axis represents transmission efficiency. It can be seen that the efficiency curve of the conventional system exhibits significant periodic failure characteristics: when the rotation angle approaches 90° and 270°, its efficiency drops to near 0%, indicating that such structures cannot transmit energy at these specific angles; while near 0°, 180°, and 360°, the efficiency recovers to a higher level, indicating that the conventional system is sensitive to the relative angle between the receiving and transmitting coils, exhibiting a typical directional coupling bottleneck.

[0043] In contrast, the structure proposed in this invention maintains an efficiency of over 90% throughout the entire rotation range, with minimal fluctuations in the curve. Even at the 90° and 270° positions where traditional structures would completely fail, it maintains stable efficiency. This result demonstrates that the improved structure effectively mitigates the destructive effect of rotational offset on the magnetic coupling path, achieving near-full-angle high-efficiency power transmission capability.

[0044] Simulation comparison and analysis of the anti-horizontal offset performance of different transmitting coil structures.

[0045] Figure 12 The Conventional Structure refers to the traditional system, while The Structure Proposed refers to the system of this invention. Figure 12 As can be seen, the UWPT system proposed in this invention outperforms the traditional system in terms of coupling coefficient. The coupling coefficient of the traditional system remains at approximately 0.2, gradually decreasing with increasing offset distance. This indicates that in the unoptimized system, the coupling coefficient is highly sensitive to horizontal offset and has a low overall coupling coefficient, resulting in low power transmission efficiency. In contrast, the structure proposed in this invention maintains a coupling coefficient k of approximately 0.26, and during horizontal offset, the overall transmission efficiency is improved by 30%, significantly higher than the unoptimized system. More importantly, the coupling coefficient remains stable across the entire offset angle range without significant changes. This demonstrates that the optimized system not only improves the coupling coefficient, thereby increasing power transmission efficiency, but also enhances its tolerance to horizontal offset, enabling the system to maintain efficient power transmission under various offset conditions.

[0046] Figure 13 The vertical axis represents the self-inductance value. In the graph, the yellow line represents the self-inductance value of a conventional receiving coil, the blue line represents the self-inductance value of the receiving coil of this invention, the orange line represents the self-inductance value of a conventional transmitting coil, and the green line represents the self-inductance value of the transmitting coil of this invention. Figure 13 It can be seen that the self-inductance of the transmitting coil proposed in this invention exhibits better stability during horizontal offset. Compared with the transmitting coil of a conventional system, the self-inductance of the structure proposed in this invention changes less with increasing offset distance. When the receiving coil is horizontally offset from 0mm to 200mm, the self-inductance of the transmitting coil of the conventional system decreases from 120uH to 106uH, a change of 14uH, with a change rate of 11.7%; the self-inductance of the optimized transmitting coil decreases from 115uH to 106.7uH, a change of 8.3uH, with a change rate of 7.5%. The stability of the self-inductance of the optimized transmitting coil during horizontal offset is improved by approximately 1.56 times, indicating that the optimized transmitting coil is less sensitive to positional changes. Furthermore, compared with the conventional system, the receiving coil designed in this invention has a smaller self-inductance and changes less with horizontal offset.

[0047] Simulation comparison and analysis of the anti-rotational offset performance of different transmitting coil structures.

[0048] Figure 14 In the diagram, the horizontal axis represents the rotation offset angle, blue represents the curve of a conventional transmitting coil, and orange represents the curve of the transmitting coil of this invention. According to... Figure 13 The coupling coefficient k of the conventional system and the system proposed in this invention are compared with the change of rotational offset angle. The coupling coefficient k of the conventional system fluctuates around 0.2. In contrast, the coupling coefficient k of the structure proposed in this invention fluctuates around 0.26. Numerical analysis shows that the average value of the optimized coupling coefficient is improved by about 30%. A larger k indicates stronger magnetic coupling between the transmitting coil and the receiving coil, thereby improving energy transmission efficiency. Therefore, the optimized system will exhibit higher output power and lower loss in practical applications, improving the robustness of the system under non-ideal alignment conditions, which is particularly important for dynamic or offset scenarios in practical applications.

[0049] like Figure 15 As shown, the self-inductance of the transmitting coil in the conventional structure and the structure proposed in this invention changes with the rotational offset angle. The orange line represents the variation curve of the structure of this invention, and the blue line represents the variation curve of the conventional structure. The self-inductance value of the conventional structure exhibits periodic fluctuations during rotational offset, ranging from approximately 100uH to 120uH. In contrast, the optimized self-inductance value fluctuates less, approximately between 115uH and 120uH. This improved self-inductance stability means that the transmitting coil proposed in this invention can better maintain the resonant frequency of the system during rotational offset, thereby improving power transmission efficiency. Specific numerical analysis shows that the optimized self-inductance value fluctuation range is reduced by approximately 9.09%, significantly reducing the system's sensitivity to offset.

[0050] Natural decoupling between receivers is achieved through the mutual cancellation of positive and negative coupling. This design maintains efficient power transmission even under rotational offset conditions. Furthermore, since the transmitting coil is larger than the receiving coil, the effective projected area remains unchanged when the receiving coil rotates.

[0051] Simulation and experimental results show that the naturally decoupled non-uniform coil structure proposed in this invention significantly reduces self-inductance fluctuations during offset and improves coupling retention capability, enabling the system to maintain stable energy transfer performance under both horizontal and rotational offsets. The improved coil design effectively enhances the system's anti-offset capability and operational robustness. Within a lateral offset range of 0-200 mm and a rotational offset angle of 0°-360°, the proposed coil structure maintains a power transfer efficiency of over 90% and significantly reduces self-inductance fluctuations compared to traditional structures with the same coil structure.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A WPT system design method based on non-uniform coils, applied to marine environments, characterized in that, include: S1: Construct a UWPT system with non-uniform coils. The UWPT system includes an energy inverter module, an LCC-S resonant compensation network, a non-uniform natural decoupling coupling mechanism, and an energy receiving and rectifying module. The non-uniform natural decoupling coupling mechanism includes a transmitting coil and a receiving coil with a reconfigured coil structure using natural decoupling. S2: Within a preset size range, a candidate set of the overall size of the transmitting coil is set, and each candidate size value is greater than the overall size of the receiving coil; the size is the equivalent outer envelope size; S3: For each size candidate value in the overall size candidate set, change the number of turns of the transmitting coil, extract the self-inductance of the transmitting coil under different numbers of turns through finite element simulation, and filter out the number of turns that makes the difference between the self-inductance of the transmitting coil and the self-inductance of the receiving coil not exceed a preset threshold, thus forming a number of turns candidate set corresponding to the size candidate value. S4: For each size-turns combination consisting of the overall size candidate value and the number of turns in the corresponding turn number candidate set, a three-dimensional finite element simulation model is established. Multiple offset conditions including different horizontal offset distances and different rotational offset angles are applied to the receiving coil. The offset condition coefficients under each offset condition are extracted. The offset condition coefficients include the self-inductance of the transmitting coil, the self-inductance of the receiving coil, the mutual inductance between the transmitting coil and the receiving coil, and the eddy current equivalent resistance caused by eddy current loss generated by the UWPT system in the seawater medium. S5: Based on multiple sets of offset operating parameters, calculate the anti-offset performance index for each size-turns combination; the performance index includes the average fluctuation of the transmitting coil, the average fluctuation of the receiving self-inductance, the coupling coefficient, the transmission efficiency, and the input and output power; S6: Based on the principle of prioritizing anti-migration performance, the optimal combination is selected and the final parameters are determined based on the performance indicators under multiple misalignment conditions.

2. The WPT system design method based on non-uniform coils according to claim 1, characterized in that, The energy inverter module includes a DC power supply and a full-bridge inverter circuit, which is used to convert the DC power supplied by the DC power supply into high-frequency AC power and provide excitation energy for the system. The LCC-S resonant compensation network includes a primary-side LCC compensation network and a secondary-side series compensation network. The primary-side LCC compensation network and the transmitting-side coil form an LCC resonant topology, which is used to excite the transmitting-side coil to generate a constant high-frequency AC current based on the high-frequency AC current output by the energy inverter module, thereby reducing reactive power loss. The secondary-side series compensation network and the receiving-side coil form a series resonant topology, which is used to convert the high-frequency AC voltage induced by the receiving-side coil into a high-frequency AC current in the secondary circuit, thereby improving energy transmission efficiency. The transmitting coil is used to receive the high-frequency alternating current provided by the primary-side LCC compensation network and generate an alternating magnetic field of the same frequency in the surrounding space; the receiving coil is used to induce a high-frequency alternating voltage at both ends of the receiving coil based on the alternating magnetic field through electromagnetic induction, and to achieve natural decoupling by reconstructing the coil structure to cancel out the positive and negative coupling between adjacent sub-coils. The energy receiving and rectifying module includes a full-bridge rectifier circuit and a load, used to rectify the high-frequency AC current converted by the secondary-side series compensation network into DC voltage and provide DC output to the load. The output terminal of the energy inverter module is connected to the input terminal of the primary-side LCC compensation network, and the output terminal of the primary-side LCC compensation network is connected to the input terminal of the transmitting-side coil; the output terminal of the receiving-side coil is connected to the input terminal of the secondary-side series compensation network, and the output terminal of the secondary-side series compensation network is connected to the input terminal of the energy receiving rectifier module.

3. The WPT system design method based on non-uniform coils according to claim 2, characterized in that, The transmitting coil L P Including the first transmitter coil L connected in series T1 Second transmitting sub-coil L T2 Third transmitting sub-coil L T3 and the fourth transmitting sub-coil L T4 ; Wherein, the first transmitting sub-coil L T1 and the fourth transmitting sub-coil L T4 They are respectively connected to the output terminals of the primary-side LCC compensation network.

4. The WPT system design method based on non-uniform coils according to claim 2, characterized in that, The receiving coil of the reconstructed coil structure employing natural decoupling includes a first array coil L. R10 Second array coil L R20 The first array coil L R10 Including the first receiving sub-coil L connected in series R1 and the fourth receiver coil L R4 Second array coil L R20 Including the second receiving sub-coil L R2 and the third receiving sub-coil L R3 ; Wherein, the first receiving sub-coil L R1 and the fourth receiver coil L R4 They are respectively connected to the input terminals of the secondary-side series compensation network.

5. The WPT system design method based on non-uniform coils according to claim 2, characterized in that, Based on multiple sets of offset load parameters, the offset resistance performance index for each size-turns combination is calculated, including: Calculate the fluctuation of the self-inductance of the transmitting coil and the receiving coil under all offset conditions, and calculate the average value of the fluctuation of the transmitting coil and the receiving coil respectively; the fluctuation is the difference between the self-inductance value when there is no offset and the self-inductance value when there is an offset. Calculate the average fluctuation of the coupling coefficient under all offset conditions, where the expression for the coupling coefficient is: in, The coupling coefficient is... For the mutual inductance of the transmitting coil and the receiving coil, For the self-inductance of the transmitting coil, The self-inductance of the transmitting coil; The formulas for calculating transmission efficiency and input / output power are as follows: in, For output power, For input power, For transmission efficiency, This is the input current of the primary-side LCC compensation network. and The branch currents of the first array coil and the second array coil are denoted as . and This is the equivalent resistance of the full-bridge rectifier circuit; and The equivalent resistance of the eddy current; This is the excitation voltage output by the full-bridge inverter circuit. For angular frequency operators, and For the mutual inductance between the transmitting coil and the two array coils, This refers to the parallel compensation capacitor in the primary-side LCC compensation network.

6. The WPT system design method based on non-uniform coils according to claim 1, characterized in that, Based on the principle of prioritizing anti-migration performance, the optimal combination of parameters is selected and the final parameters are determined based on performance indicators under multiple misalignment conditions, including: For all size-turns combinations, performance metrics under multiple offset conditions were selected in the following order: First priority: compare the average self-inductance fluctuation of the transmitting coil with the average self-inductance fluctuation of the receiving coil, and select size-turns combinations in which both are less than a preset threshold. The second priority is to select size-turn combinations from the size-turn combinations selected by the first priority that have an average coupling coefficient fluctuation of less than a preset threshold. The third priority is to select size-turns combinations that have an average transmission efficiency greater than a preset threshold under offset conditions from the size-turns combinations selected by the second priority. The fourth priority is to select the size-turns combination with the highest average input power and output power from the size-turns combinations selected in the third priority. The fifth priority is to select the optimal combination of size-turns ratio from the size-turns ratio combinations selected in the fourth priority selection. The emitter coil size and number of turns corresponding to the optimal combination selected in the final screening will be used as the final circuit design parameters.

7. The WPT system design method based on non-uniform coils according to claim 2, characterized in that, In the energy inverter module, the DC power supply is connected to the input terminal of the full-bridge inverter circuit. The full-bridge inverter circuit includes a first switch S1 with an anti-parallel diode, a second switch S2 with an anti-parallel diode, a third switch S3 with an anti-parallel diode, and a fourth switch S4 with an anti-parallel diode. The drain of the first switching transistor S1 with anti-parallel diode is connected to the positive bus of the DC power supply, and the source is connected to the left half-bridge node as one end of the AC output terminal; the gate is connected to the drive control signal. The source of the second switch S2 with anti-parallel diode is connected to the negative bus of the DC power supply, and the drain of the switch S2 with anti-parallel diode is connected to the same node as the source of the first switch S1 with anti-parallel diode, which together serve as one end of the AC output terminal; the gate is connected to the drive control signal. The drain of the third switching transistor S3 with anti-parallel diode is connected to the positive bus of the DC power supply; the source is connected to the right half-bridge node, serving as the other end of the AC output terminal; and the gate is connected to the drive control signal. The source of the fourth switch S4 with anti-parallel diode is connected to the negative bus of the DC power supply; the drain of the switch S4 with anti-parallel diode is connected to the same node as the source of the third switch S3 with anti-parallel diode, and together they serve as the other end of the AC output terminal. The gate is connected to the drive control signal.

8. The WPT system design method based on non-uniform coils according to claim 3, characterized in that, The primary-side LCC compensation network includes a first inductor L f Parallel compensation capacitor C f Second capacitor C p The secondary-side series compensation network includes a second capacitor C. R10 and the third capacitor C R20 ; The first inductor L f One end is connected to the right half-bridge node, and the other end is connected to the parallel compensation capacitor C. f and the first capacitor C p One end is connected to the parallel compensation capacitor C. f The other end is connected to the fourth transmitting sub-coil L T4 One end is connected; the first capacitor C p The other end is connected to the first transmitting sub-coil L T1 One end is connected; The second capacitor C R10 One end is connected to the first receiving sub-coil L R1 One end is connected to the third capacitor C. R20 One end is connected to the second receiving sub-coil L R2 One end is connected.

9. The WPT system design method based on non-uniform coils according to claim 8, characterized in that, The full-bridge rectifier circuit includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, and a fourth capacitor C. s1 and the fifth capacitor C s2 ; The anode of the first diode D1 is connected to the second capacitor C R10 The other end is connected, with the cathode connected to the cathode of the third diode D3; the cathode of the second diode D2 is connected to the anode of the first diode D1, and the anode is connected to the anode of the fourth diode D4; the cathode of the third diode D3 is connected to the fourth capacitor C. s1 One end is connected, and the anode of the third diode D3 is connected to the fourth receiving sub-coil L. R4 One end of the diode is connected to the cathode of the fourth diode D4; the cathodes of the fifth diode D5 and the seventh diode D7 are connected, and their anodes are connected to the third capacitor CR. 20 The other end is connected to the cathode of the sixth diode D6; the anode of the sixth diode D6 is connected to the anode of the eighth diode D8; the cathode of the seventh diode D7 is connected to the fifth capacitor C. s2 One end is connected, and the anode is connected to the cathode of the eighth diode D8 and the third receiver coil L, respectively. R3 One end is connected; the anode of the eighth diode D8 is connected to the fifth capacitor C. s2 The other end is connected; Fourth capacitor C s1 One end is connected to the load R L One end is connected to the fifth capacitor C. s2 The other end is connected to the load R L The other end is connected.

Images