Double U-shaped coupling mechanism and underwater constant voltage wireless charging system and parameter design method

Abstract

This invention provides a dual U-shaped coupling mechanism and an underwater constant-voltage wireless charging system and parameter design method. By optimizing the coil structure and parameter design method, it has strong applicability to underwater enclosed wireless charging, can significantly suppress mutual inductance drop, and maintain a high mutual inductance level to reduce seawater eddy current loss. It achieves constant voltage output for loads with different voltage requirements and power levels within a large angular offset range, improving the universality and adaptability of the underwater wireless charging system for underwater electromechanical equipment with different power requirements. At the same time, it takes into account the small size and weight of the system, which is more conducive to realizing the unmanned operation of the underwater wireless charging system.

Description

Technical Field

[0001] This invention relates to wireless power transmission technology, specifically to a double U-shaped coupling mechanism and an underwater constant voltage wireless charging system and parameter design method. Background Technology

[0002] Magnetic Coupling Wireless Power Transfer (MC-WPT) is a technology that uses an alternating magnetic field as the energy transfer carrier and integrates power electronics, electrical engineering theory, and control technologies to achieve power transfer without direct electrical contact. With the gradual maturation of its theoretical framework and in-depth research into its key technologies, MC-WPT has received increasing attention, and its practical application has been greatly promoted. In recent years, the intelligent development of underwater electromechanical equipment has accelerated, leading to a rapid increase in its application in underwater power inspection and exploration. However, the issue of flexible and efficient charging is a significant factor limiting the underwater operation of such equipment. Current charging methods primarily involve replenishing power after surface retrieval, which is inefficient and lacks flexibility, significantly reducing the endurance of underwater electromechanical equipment and increasing the cost of power replenishment. Furthermore, using large-capacity batteries increases the system's size and weight.

[0003] MC-WPT technology for underwater power replenishment eliminates the need for physical circuit connections between the power transmitter and receiver. Once power replenishment is complete, underwater equipment can continue its tasks, enabling wireless charging without surfacing or retrieving, significantly improving safety and efficiency. However, current underwater wireless charging technologies face limitations due to the complex and variable operating environment. Large-scale displacement of the coupling mechanism caused by underwater surges alters coil inductance, and the piezomagnetic effect also causes inductance drift. Furthermore, the diverse power levels and voltage requirements of the power receiver load contribute to the inability of the MC-WPT system to maintain a constant output voltage, hindering its applicability to loads with varying power levels and voltage requirements over a wide range of displacements. Additionally, underwater magnetic coupling wireless charging technology imposes strict limitations on system size, weight, and stability. Existing constant-voltage output control technologies for MC-WPT systems, such as DC / DC circuits, tuning control, and short-circuit decoupling, suffer from limitations in underwater applications due to circuit complexity, control difficulty, and increased system size.

[0004] Phase-shift control offers advantages such as circuit simplicity, low control difficulty, and reduced system size, making it highly suitable for constant voltage output control in underwater MC-WPT systems. However, its voltage regulation range is relatively small, requiring the underwater MC-WPT system coupling mechanism to exhibit minimal mutual inductance drop over large offsets. Currently available underwater wireless charging systems exhibit poor offset resistance and require high precision in their docking methods, increasing system control complexity and negatively impacting output voltage stability. Furthermore, current output voltage control for underwater wireless charging systems is only applied to situations with a single load parameter variation, resulting in relatively simple load conditions. The coupling mechanism and resonant network parameters are often designed empirically, without specific design methods for the coupling mechanism and resonant parameters tailored to specific requirements. This fails to meet the output requirements of underwater wireless charging systems under varying voltage demands and load power levels within the offset range. Summary of the Invention

[0005] Based on the above requirements, the primary objective of this invention is to propose a double U-shaped coupling mechanism with anti-displacement properties, which can adapt to wireless power transmission in underwater surge environments while taking into account the requirements of small system size and weight.

[0006] To achieve the above objectives, the specific technical solution adopted by the present invention is as follows:

[0007] A dual U-shaped coupling mechanism includes a transmitting coil and a receiving coil. The key feature is that the transmitting coil is disposed on a first arc surface and includes at least one transmitting sub-coil. The transmitting sub-coil includes an inner first loop-shaped transmitting coil and an outer second loop-shaped transmitting coil, which are bent into a U-shape along the first arc surface and connected in series with opposite directions. The receiving coil is disposed on a second arc surface concentric with the first arc surface and includes at least one receiving sub-coil, which is a loop-shaped receiving coil bent into a U-shape along the second arc surface.

[0008] Optionally, three transmitting sub-coils are distributed circumferentially on the first arc surface, and a transmitting end mounting base with an arc surface is provided for each transmitting sub-coil.

[0009] Optionally, three receiving sub-coils are distributed circumferentially on the second arc surface, and a receiving end mounting base with an arc surface is provided for each receiving sub-coil.

[0010] Optionally, the radius of the first arc surface is greater than the radius of the second arc surface, the transmitting sub-coil is disposed on the concave arc surface inside the transmitting end mounting base, and the receiving sub-coil is disposed on the convex arc surface outside the receiving end mounting base, and the transmitting sub-coil and the receiving sub-coil are disposed in a one-to-one correspondence.

[0011] Optionally, the transmitter mounting base is equipped with an energy transmitting circuit and a transmitter magnetic shielding layer, and the receiver mounting base is equipped with an energy receiving circuit and a receiver shielding layer.

[0012] Optionally, the transmitter mounting base is fixed to the energy transmitter device via a telescopic mechanism, and the receiver mounting base is fixedly connected to the energy receiver device.

[0013] Based on the aforementioned double U-shaped coupling mechanism, a second objective of this invention is to propose an underwater constant-voltage wireless charging system, comprising an energy transmitting device and an energy receiving device, wherein the energy transmitting device and the energy receiving device are coupled using the aforementioned double U-shaped coupling mechanism, thereby meeting the power supply requirements of underwater electromechanical equipment.

[0014] To adapt to different offset conditions, the energy transmitting device may optionally be equipped with a DC power supply and an inverter module. The inverter module is connected in parallel to three energy transmitting circuits, and each energy transmitting circuit is connected to a transmitting sub-coil. The electrical load of the energy receiving device is powered by the three energy receiving circuits in parallel, and each energy receiving circuit is connected to a receiving sub-coil.

[0015] The energy transmitting device is further equipped with a transmitting end control module, which is configured with a first communication module and a drive circuit for driving the inverter module. A voltage sampling circuit is also connected to the electrical load, and the voltage sampling circuit is connected to the receiving end control module. A second communication module is configured on the receiving end control module. The transmitting end control module establishes a communication connection with the receiving end control module through the first communication module and the second communication module to receive the voltage status of the electrical load and realize phase shift control of the inverter module.

[0016] Based on the above-described double U-shaped coupling mechanism, a third objective of this invention is to propose a parameter design method for the aforementioned double U-shaped coupling mechanism, the key of which includes the following steps:

[0017] S1: Determine d based on the application scenario p d s V out P out , ω, r p r s And set I p0 Initial value I0; where d p Let d be the side length of the transmitting sub-coil. s V is the side length of the receiving sub-coil. out To receive the output voltage of the sub-coil, P out To receive the output power of the sub-coil, ω is the operating angular frequency, and r pr is the diameter of the transmitting sub-coil (cable cross-sectional diameter). s For the receiving sub-coil wire diameter, I p0 I0 is the rated current of the transmitter sub-coil, and I0 is the rated current corresponding to the initial wire diameter of the transmitter sub-coil.

[0018] S2: Determine the total number of turns N of the transmitter sub-coil p0 =d p / (2r p The total number of turns N in the receiving sub-coil s0 =d s / (2r s Mutual inductance coefficient And set variable N p1 =N p2 =N s =0, where N p1 N represents the number of turns of the first loop-shaped transmitting coil. p2 N represents the number of turns of the second loop-shaped transmitting coil. s This refers to the number of turns of the receiving sub-coil;

[0019] S3: Set N p1 =N p1 +1, and determine N p1 ≥N p0 If the condition is met, proceed to step S7; otherwise, proceed to step S4.

[0020] S4: Set N p2 =N p2 +1, and determine N p1 +N p2 >N p0 Is it true? If it is true, then set N. p2 If the value is 0, return to step S3; otherwise, proceed to step S5.

[0021] S5: Set N s =N s +1, and determine N s >N s0 Is it true? If it is true, then set N. s If the value is 0, return to step S4; otherwise, proceed to step S6.

[0022] S6: Determine M min >M0 and M min / M max Check if <0.95 is true. If true, keep the current solution as a candidate parameter and return to step S5; otherwise, return directly to step S5; where M min M is the minimum mutual inductance value within a predetermined offset angle range under the current parameters. max This represents the maximum mutual inductance value within the predetermined offset angle range under the current parameters.

[0023] S7: Determine if there are any alternative parameters. If so, select the parameter with the largest mutual inductance value as the current parameter value; otherwise, set I. p0 =I p0 +ΔI, and adjust r p Return to step S2 to redesign, where ΔI represents the adjustment step of the recommended current of the transmitter coil.

[0024] Optionally, the transmitting coil is provided with three transmitting sub-coils, and the receiving coil is provided with three receiving sub-coils, wherein the parameters of the three transmitting sub-coils are the same, and the parameters of the three receiving sub-coils are the same.

[0025] The effects of this invention are:

[0026] The double U-shaped coupling mechanism proposed in this invention achieves constant voltage output for loads with different power levels and voltage requirements within a large offset range. When applied to an underwater wireless charging system, it improves the universality and adaptability of the underwater wireless charging system for underwater electromechanical equipment with different power requirements, while also taking into account the small size and weight of the system, which is more conducive to realizing the unmanned operation of the underwater wireless charging system. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0028] Figure 1 This is a schematic diagram of the double U-shaped coupling mechanism provided by the present invention;

[0029] Figure 2 for Figure 1 A schematic diagram of the structure of the first loop-shaped transmitting coil and the second loop-shaped transmitting coil in the double U-shaped coupling mechanism shown;

[0030] Figure 3 This is a schematic diagram of a double U-shaped coupling mechanism with multiple transmitting sub-coils in a specific embodiment of the present invention;

[0031] Figure 4 for Figure 3 The diagram shows the offset state of the double U-shaped coupling mechanism.

[0032] Figure 5 for Figure 1 The parameter design flowchart of the double U-shaped coupling mechanism is shown.

[0033] Figure 6 A comparison of the anti-displacement effects of different coupling mechanisms;

[0034] Figure 7This is a circuit topology diagram of an underwater constant-voltage wireless charging system in a specific embodiment of the present invention;

[0035] Figure 8 This is the equivalent circuit of the LCC / S resonant compensation network;

[0036] Figure 9 The phase shift angle θ and the inverter voltage v inv Relationship curve diagram;

[0037] Figure 10 This is a block diagram of the phase-shifting control system.

[0038] Figure 11 Design a flowchart for system parameters;

[0039] Figure 12 The waveforms of power level switching voltage and current under the 0° offset condition in simulation scenario 1 are shown.

[0040] Figure 13 The waveforms of power level switching voltage and current under a 15° offset in simulation scenario 1 are shown.

[0041] Figure 14 The waveforms of power level switching voltage and current under the 0° offset condition in simulation scenario 2 are shown.

[0042] Figure 15 The waveforms of power level switching voltage and current are shown in simulation scenario 2 with a 15° offset. Detailed Implementation

[0043] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0044] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0045] like Figure 1 and Figure 2 As shown, this embodiment provides a double U-shaped coupling mechanism, including a transmitting coil and a receiving coil. The transmitting coil is disposed on a first arc surface and includes at least one transmitting sub-coil. The transmitting sub-coil includes an inner first loop-shaped transmitting coil and an outer second loop-shaped transmitting coil. The first and second loop-shaped transmitting coils are bent into a U-shape along the first arc surface, connected in series and wound in opposite directions. Figure 2As can be seen, in this example, the inner first loop-shaped transmitting coil is wound in the reverse direction, the outer second loop-shaped transmitting coil is wound in the forward direction, and the receiving coil is set on the second arc surface concentric with the first arc surface, and includes at least one receiving sub-coil. The receiving sub-coil is a loop-shaped receiving coil, which is bent into a U-shape along the second arc surface.

[0046] In response to the requirements of underwater wireless charging applications, energy transmitters and receivers typically employ a nested structure. In this embodiment, the energy transmitter is located on the outer side, and the energy receiver is located on the inner side. Therefore, the radius of the first arc surface is larger than the radius of the second arc surface. Considering the need for clamping and fixing the energy receiver, this invention adopts a multi-point wireless energy transmission structure. Figure 3 As can be seen, three transmitting sub-coils are distributed circumferentially on the first arc surface, and each transmitting sub-coil is provided with a transmitter mounting base with an arc surface. The transmitting sub-coil is set on the concave arc surface inside the transmitter mounting base. Correspondingly, three receiving sub-coils are distributed circumferentially on the second arc surface, and each receiving sub-coil is provided with a receiver mounting base with an arc surface. The receiving sub-coils are set on the convex arc surface outside the receiver mounting base. The transmitting sub-coils and receiving sub-coils are arranged in a one-to-one correspondence. The three-transmitter and three-receiver structure not only takes into account the function of tightening and fixing, but also improves the power transmission capability under the same conditions.

[0047] In practice, the transmitter mounting base is usually equipped with a waterproof and pressure-bearing shell and is fixed to the charging docking device frame configured on the energy transmitting device through a telescopic mechanism. The interior is equipped with an energy transmitting circuit and a transmitter magnetic shielding layer. The energy transmitting circuit is mainly a resonant circuit and is connected to the output of the inverter through a watertight connector. The telescopic mechanism can be a hydraulic telescopic rod, so that the whole device constitutes an electric energy transmitting and fixing device.

[0048] Taking the power supply scenario of underwater robots as an example, the receiver mounting base is usually equipped with a waterproof and pressure-bearing shell and is set on the outer wall of the underwater robot as a power receiving device. The receiver mounting base is equipped with an energy receiving circuit and a receiver shielding layer. The energy receiving circuit is usually a resonant and rectifier circuit and is connected to the battery pack through a watertight connector.

[0049] pass Figure 4 It can be seen that, using Figure 3The double U-shaped coupling mechanism shown in this invention addresses the issue that, due to the surge effect on underwater robots, even when multiple power transmitting and fixing devices are clamped within the charging docking device frame, precise alignment between the transmitting and receiving sub-coils is difficult, often resulting in angular misalignment. This invention's double U-shaped coupling mechanism compensates for mutual inductance drops in the rotational angle direction by connecting an external forward-wound U-shaped coil and an internal reverse-wound U-shaped coil in series. Furthermore, through rational design of the wire diameter and number of turns of the transmitting-end forward-wound U-shaped coil, the transmitting-end reverse-wound U-shaped coil, and the receiving coil, the new coupling mechanism maintains the mutual inductance value at an optimal level while meeting the anti-mutual inductance drop conditions. This reduces the transmitting coil current and effectively minimizes seawater eddy current losses. The specific parameter design process is as follows: Figure 5 As shown.

[0050] Therefore, this embodiment also provides a parameter design method for a double U-shaped coupling mechanism, through... Figure 5 As can be seen, it includes the following steps:

[0051] S1: Determine d based on the application scenario p d s V out P out , ω, r p r s And set I p0 Initial value I0;

[0052] Based on the device dimensions, both the transmitting and receiving coils can be predefined as square regions, thus determining the side length d of the transmitting sub-coil. p and the side length d of the receiver sub-coil s To reduce seawater loss, the underwater operating frequency is set to 150kHz, thus defining the operating angular frequency ω. Based on the power requirements of the receiver, the output power P of the receiving sub-coil can be predetermined. out and the output voltage V of the receiving sub-coil out ,according to Calculate the receiving coil current I s and according to I s The maximum value is selected based on the wire diameter r of the receiver sub-coil. s , where n c Let n be the number of transmitting sub-coils. c The value is 3.

[0053] In close-range transmission, to further reduce seawater eddy current losses, mutual inductance should be increased as much as possible while reducing the primary coil current. First, the rated current I of the transmitting coil should be set. p0 =I0, to ensure a larger solution range, the initial value of the rated current I0 of the transmitting coil should be relatively small, thus selecting the wire diameter r of the transmitting sub-coil. p .

[0054] S2: Since underwater wireless charging systems generally have strict size limitations, a close-wound coil is usually used when space is limited, which allows us to determine the total number of turns N of the transmitter sub-coil. p0 =d p / (2r p The total number of turns N in the receiving sub-coil s0 =d s / (2r s The total number of turns in the coil above is a theoretical value; in actual operation, it should be adjusted appropriately based on the coil winding conditions. (Based on the output voltage V...) out and the rated current I of the transmitting coil p0 Minimum mutual inductance requirement can be calculated

[0055] This invention verifies whether the mutual inductance meets preset requirements by setting a counter variable and sequentially changing the number of turns of the first loop-shaped transmitting coil, the second loop-shaped transmitting coil, and the receiving sub-coil. Therefore, in this step, the variable N is set. p1 =N p2 =N s =0, where N p1 N represents the number of turns of the first loop-shaped transmitting coil. p2 N represents the number of turns of the second loop-shaped transmitting coil. s This refers to the number of turns of the receiving sub-coil;

[0056] S3: Set N p1 =N p1 +1, and determine N p1 ≥N p0 If the condition is met, proceed to step S7; otherwise, proceed to step S4.

[0057] S4: Set N p2 =N p2 +1, and determine N p1 +N p2 >N p0 Is it true? If it is true, then set N. p2 If the value is 0, return to step S3; otherwise, proceed to step S5.

[0058] S5: Set N s =N s +1, and determine N s >N s0 Is it true? If it is true, then set N. s If the value is 0, return to step S4; otherwise, proceed to step S6.

[0059] S6: Determine M min >M0 and M min / M maxCheck if <0.95 is true. If true, keep the current solution as a candidate parameter and return to step S5; otherwise, return directly to step S5; where M min M is the minimum mutual inductance value within a predetermined offset angle range under the current parameters. max This represents the maximum mutual inductance value within the predetermined offset angle range under the current parameters.

[0060] S7: Determine if there are any alternative parameters. If so, select the parameter with the largest mutual inductance value as the current parameter value; otherwise, set I. p0 =I p0 +ΔI, and adjust r p Return to step S2 for redesign, where ΔI represents the adjustment step of the rated current of the transmitter coil.

[0061] pass Figure 5 It can be seen that for N p1 N p2 N s In all cases, a turns count scan is performed, retaining those that satisfy the condition that the minimum mutual inductance is greater than M0 and the mutual inductance drop is less than 5% (M min >M0 and M min / M max Numerical solutions with a mutual inductance <0.95 were selected, and the set of solutions with the highest mutual inductance was finally determined for winding. If no numerical solution satisfies the condition under the current recommended current of the transmitting coil, the recommended current I of the transmitting coil is increased. p0 =I p0 Similarly, to ensure a larger solution range, ΔI is taken as a smaller value, and the transmitting coil wire diameter r is reselected. p Perform the turns count scan again until a value satisfying M is found. min >M0 and M min / M max The numerical solution with a mutual inductance of less than 0.95 is selected, and the number of turns of the coil with the maximum mutual inductance is the scheme with the lowest seawater loss under the same conditions.

[0062] In specific implementation, combined with Figure 3 The structure shown is such that the transmitting coil is provided with three transmitting sub-coils and the receiving coil is provided with three receiving sub-coils, the parameters of the three transmitting sub-coils are the same, and the parameters of the three receiving sub-coils are the same.

[0063] Regarding the underwater robot provided in this embodiment, its system design requirements are: transmitter size 35cm*35cm, receiver size 22cm*22cm, input voltage 300V, output voltage 350V corresponding to output power 500W-2500W, and output voltage 600V corresponding to output power 500W-5000W. Figure 5The design flow of the coupling mechanism parameters is shown, and the design results are shown in Table 1. Parameter scanning of the mutual inductance of the double U-shaped coupling mechanism was performed with a coil distance of 4cm and an angle offset of ±15°. The mutual inductance drop of the flat plate type, ordinary U-shaped, and double U-shaped coupling mechanisms were compared under the same size, transmission distance, and mutual inductance level. The comparison results are shown below. Figure 6 As shown in Table 2.

[0064] Table 1 Parameters of the Double U-Shaped Coupling Mechanism

[0065]

[0066] Table 2 Mutual Inductance Offset of Coupled Mechanism

[0067]

[0068] Depend on Figure 6 As shown in Table 2, for the same size and distance, the planar coil exhibits the most severe mutual inductance drop under angular deviation, with a 24.7% drop within ±15° of the angular deviation. The ordinary U-shaped coil shows better mutual inductance drop than the planar coil under angular deviation, but still experiences a significant drop, with a 15.4% drop within ±15°. Both types of coils are detrimental to the system's output voltage stability, increasing control difficulty and current stress on power devices. The double U-shaped coil, with the addition of a reverse-wound coil, significantly improves mutual inductance drop under the same mutual inductance level through turns design, with a drop of only 1.8% within ±15° of the angular deviation. Simulation results demonstrate that the proposed double U-shaped coil is highly applicable to underwater enclosed wireless charging, significantly suppressing mutual inductance drop while maintaining a high mutual inductance level to reduce seawater eddy current losses.

[0069] Based on the above effects, this embodiment also utilizes the double U-shaped coupling mechanism designed by the above parameter design method to construct an underwater constant voltage wireless charging system, including an energy transmitting device and an energy receiving device. The energy transmitting device and the energy receiving device adopt the double U-shaped coupling mechanism described above. This underwater constant voltage wireless charging system meets the power supply requirements of underwater electromechanical equipment.

[0070] Combination Figure 7 It can be seen that the energy transmitting device is equipped with a DC power supply and an inverter module. The inverter module is connected in parallel to three energy transmitting circuits. Each energy transmitting circuit is connected to a transmitting sub-coil. The electrical load of the energy receiving device is powered by the three energy receiving circuits in parallel. Each energy receiving circuit is connected to a receiving sub-coil.

[0071] The energy transmitting device is further equipped with a transmitting end control module, which is configured with a first communication module and a drive circuit for driving the inverter module. A voltage sampling circuit is also connected to the electrical load, and the voltage sampling circuit is connected to the receiving end control module. A second communication module is configured on the receiving end control module. The transmitting end control module establishes a communication connection with the receiving end control module through the first communication module and the second communication module to receive the voltage status of the electrical load and realize phase shift control of the inverter module.

[0072] Figure 7 In the middle, the power transmitting end includes a DC power supply V. dc The system consists of a full-bridge inverter (composed of four MOSFETs Q1-Q4), three sets of resonant networks with identical parameters, and a transmitting coil. Each set of resonant networks and transmitting coils is connected in parallel, including the transmitting resonant inductor L. f1 L f2 L f3 The transmitter has a parallel resonant capacitor C. r1 C r2 C r3 The transmitter series resonant capacitor C p1 C p2 C p3 The self-inductance of the transmitting coil L p1 L p2 L p3 The power receiving end includes a load and three sets of identical receiving coils, compensation capacitors, and rectifier / filter circuits. Each set of receiving coils, compensation capacitors, and rectifier / filter circuits is connected in parallel, including the self-inductance L of the receiving coil. s1 L s2 L s3 The resonant capacitor C at the receiving end s1 C s2 C s3 rectifier filter circuit (diodes D1-D) 12 (Composed of filter capacitor C) and load R L In the diagram, M1, M2, and M3 represent the mutual inductance between three sets of corresponding transmitting and receiving coils.

[0073] The transmitter MCU1, driver circuit, and transmitter WIFI1 together constitute the transmitter communication and control circuit, used for communication and phase shift control with the receiver. The receiver MCU2, voltage sampling circuit, and receiver WIFI2 together constitute the receiver communication and control circuit, used for sampling the output voltage and communicating with the transmitter.

[0074] When constructing the circuit system, since the three sets of resonant network topologies and coupling mechanism parameters are identical, it is only necessary to analyze and design the parameters for the same set of system circuit topologies. The LCC / S resonant topology is as follows: Figure 8 As shown, for the LCC / S resonant compensation topology, we have:

[0075]

[0076] Among them, Z s R is the input impedance of the receiving end. s R is the internal resistance of the receiving coil. e ω is the equivalent resistance at the input of the rectifier bridge. ω is the system angular frequency, and Z is the reflection impedance. r for:

[0077]

[0078] The total input impedance Z of the system in for:

[0079]

[0080] Let the system input impedance Z in If the imaginary part is 0, then:

[0081]

[0082] Substituting this into the previous formula, we get:

[0083]

[0084] According to the impedance calculation formula, the primary coil current I can be obtained. p and secondary coil current I s They are respectively:

[0085]

[0086]

[0087] Among them, V in Given the fundamental effective value of the input voltage to the resonant network, the equivalent load voltage V can be obtained from the above equation. Re for:

[0088]

[0089] Then the voltage gain G of the resonant network v It can be represented as:

[0090]

[0091] Due to the internal resistance R of the receiving coil in the equivalent load voltage calculation formula s Typically much smaller than the equivalent resistance R e Therefore, in the theoretical analysis process, it is usually ignored for the sake of convenience in calculation. Thus, the voltage gain G of the resonant network is...v It can be simplified to:

[0092]

[0093] As shown in the voltage gain calculation formula of the resonant network, theoretically, the LCC / S resonant compensation topology has constant voltage output characteristics under constant voltage input. However, in practical engineering applications, the mutual inductance changes caused by the offset of the coupling mechanism and the changes in load power level will lead to changes in the output voltage, ultimately resulting in unstable output voltage of the system. Therefore, in practical engineering applications, relying solely on the inherent characteristics of the LCC / S type resonant topology cannot guarantee constant voltage output within a certain load range and mutual inductance variation range.

[0094] In summary, this invention also combines the phase-shift control method of the full-bridge inverter and proposes an LCC / S resonant network and switching transistor parameter design method, which enables the system to ensure constant voltage output within a certain load and mutual inductance variation range.

[0095] The so-called phase-shift control, combined with Figure 9 It can be seen that the phase shift angle θ of the inverter under phase shift control is related to the inverter output voltage v. inv The relationship is that Q1-Q4 are the four MOSFET drive waveforms, v inv This is the inverter output voltage waveform. Switches Q1 and Q2 conduct complementaryly to form one bridge arm, and switches Q3 and Q4 conduct complementaryly to form the other bridge arm. Let the inverter switching frequency be f. inv If the period is T, then the forward conduction time and reverse conduction time of the inverter are both θ / (2πf). inv )=(θ / 2π)T, where 0°≤θ≤180°, that is, when θ=0° the inverter is not conducting, and at this time the effective value of the inverter output voltage V inv When θ = 180°, the inverter conducts for half a switching cycle in both the forward and reverse directions, and V equals zero. inv The inverter output voltage v is reached at its maximum value. Therefore, during phase-shift control, the inverter output voltage v can be controlled by adjusting the phase-shift angle θ. inv The size of the voltage can be adjusted to achieve a stable output voltage.

[0096] The control block diagram of phase shift control is as follows: Figure 10 As shown, after the system starts, the output voltage V collected by the power receiving terminal is... out and load voltage requirement V ref The signal is sent to the power transmitter, where the phase-shifting PI controller adjusts the phase shift angle θ based on the error e between the output voltage and the load demand voltage, ultimately achieving a constant load voltage output. When changes in the mutual inductance of the coupling coil or the load power level cause output voltage fluctuations, the power transmitter's phase-shifting PI controller adjusts the phase shift angle θ to maintain the system output voltage V. outThis ensures constant voltage output under different power load levels and mutual inductance conditions.

[0097] Combination Figure 7 The control system shown completes a handshake between the transmitter and receiver via WIFI1 and WIFI2 after the system enters standby mode. The transmitter acquires the output voltage and the load's required voltage. The transmitter's MCU1 activates the phase shift angle and adjusts it based on the data returned from the receiver to stabilize the output voltage. After charging is complete, the receiver sets the load's required voltage to 0, the transmitter's MCU1 deactivates the phase shift angle, and the system enters standby mode.

[0098] Based on the above control process, it can be understood that when phase-shift control is used, the effective value of the fundamental frequency of the resonant network input voltage is:

[0099]

[0100] Where θ is the phase shift angle, when θ is 0° the inverter output is off, and when θ is 180° the inverter output is on for half a switching cycle in both directions. Based on the input-output voltage relationship before and after the rectifier bridge:

[0101]

[0102]

[0103] Combining the above equations, we can obtain the DC input voltage V. dc With system output voltage V out relation:

[0104]

[0105] From the above equation, it can be seen that when M decreases, the phase shift angle θ increases; when M increases, decreasing the phase shift angle θ can maintain V. out Constant output. Therefore, after determining the input and output voltages, power levels, and coupling mechanism parameters of the underwater MC-WPT system, the parameters of the system's resonant compensation network and switching transistors can be designed to meet the charging requirements of the corresponding underwater electromechanical equipment.

[0106] Based on the above analysis, the design process for the resonant parameters and switching transistor parameters of the underwater constant-voltage wireless charging system is summarized as follows:

[0107] First, the system switching frequency can generally be selected based on international standards or experience, so the switching angular frequency ω is a known parameter. Based on the known system parameters: the self-inductance L of the coupling mechanism... p L s And the minimum mutual inductance M within the entire offset range min and maximum mutual inductance M max Switching angular frequency ω, rated input voltage V dc Rated output voltage Vout and its corresponding rated output power P out ,have:

[0108]

[0109] Rated output voltage V out There can be various needs, and the output voltage can meet the power demand V under any operating condition. out The voltage boost ratio of each set of transmitting and receiving coils should be no less than V under minimum mutual inductance. out(max) / V dc ,have:

[0110]

[0111] Considering factors such as underwater resonance parameter drift, a certain phase margin θ is given. a ,have:

[0112]

[0113] θ a The value of θ should not be too large, because θ a When the value is large, the input current of the resonant network is too high during normal operation, which will lead to increased switching losses and seriously affect system efficiency. Generally, θ... a This can be obtained through simulation analysis, where θ a Take 30°.

[0114] The system resonant network parameters are calculated as follows:

[0115]

[0116] In addition, the inverter output current and input voltage, as important factors in selecting the switching transistors, are also necessary calculation parameters. Inverter output current I... inv for:

[0117]

[0118] Number of transmitter coils n c The value is set to 3, because the rated output voltage V out and rated output power P out There are multiple requirements, therefore the output current I out The demand is not unique. From the above formula, we know that when M is the maximum value M... max And the output current reaches its maximum value I. out(max) At this time, the inverter output current has a maximum value:

[0119]

[0120] If the switching transistor voltage has a 3x margin and the current has a 2x margin, then the switching transistor parameters are calculated as follows:

[0121]

[0122] Based on the above parameter design steps, the simplified parameter design flowchart is as follows: Figure 11 As shown.

[0123] In this embodiment, simulation experiments are also used to further verify the technical effects of the above-mentioned coupling mechanism and parameter design method.

[0124] Based on the parameters of the anti-offset coupling mechanism designed above, the known system parameters are shown in Table 3:

[0125] Table 3 Known System Parameters

[0126]

[0127] Based on the parameter calculation formula, the system resonance and switching transistor parameters are shown in Table 4:

[0128] Table 4 System Topology Design Parameters

[0129]

[0130] By building a Simulink simulation model, the simulation was conducted by switching the load resistance value R. L The method simulates a scenario of power level change, and the method simulates a scenario of coupling mechanism offset by changing the mutual inductance value M between the transmitting coil and the receiving coil.

[0131] Simulation Scenario 1: V out =600V, P out =500W-5kW

[0132] Simulations were performed on the switching process of 500W, 3kW, and 5kW power levels under two different bias conditions: 0° and 15°. The simulation results are as follows: Figure 12 and Figure 13 As shown.

[0133] Simulation Scenario 2: V out =350V, P out =500W-2.5kW

[0134] The switching process of 500W, 1.5kW, and 2.5kW power levels was simulated under two different bias conditions: 0° and 15°. The simulation results are as follows: Figure 14 and Figure 15 As shown.

[0135] The simulation results show that:

[0136] (1) During the charging process, the load level switching causes slight fluctuations in the output voltage. By adjusting the phase shift angle, the output voltage recovers to the rated output voltage value in a short time, ensuring the stability of the system output voltage.

[0137] (2) Within the offset range of 0-15°, the system can ensure that the output voltage reaches the rated output value and remains stable.

[0138] (3) For different output voltage and load power levels, the system can meet the rated output voltage and rated power required by the load by adjusting the phase shift angle.

[0139] In summary, the simulation results verify the effectiveness of the proposed double U-shaped coupling mechanism and underwater constant voltage wireless charging system and parameter design method in resisting displacement. At the same time, it verifies that the designed system is suitable for constant voltage output of underwater electromechanical equipment with different voltage requirements and power levels within a large underwater displacement range.

[0140] 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. Such 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, and such transformations should be covered within the scope of the claims and specification of the present invention.

Claims

1. A parameter design method for a double U-shaped coupling mechanism, the double U-shaped coupling mechanism comprising a transmitting coil and a receiving coil, the transmitting coil being disposed on a first arc surface and comprising at least one transmitting sub-coil; the transmitting sub-coil comprising an inner first loop-shaped transmitting coil and an outer second loop-shaped transmitting coil, the first loop-shaped transmitting coil and the second loop-shaped transmitting coil being bent into a U-shape along the first arc surface, and being connected in series with opposite directions of winding; the receiving coil being disposed on a second arc surface concentric with the first arc surface and comprising at least one receiving sub-coil, the receiving sub-coil being a loop-shaped receiving coil, the loop-shaped receiving coil being bent into a U-shape along the second arc surface, characterized in that, The parameter design process for the double U-shaped coupling mechanism includes the following steps: S1: Determine d based on the application scenario p d s V out P out , ω, r p r s And set I p0 Initial value I0; Where d p Let d be the side length of the transmitting sub-coil. s V is the side length of the receiving sub-coil. out To receive the output voltage of the sub-coil, P out To receive the output power of the sub-coil, ω is the operating angular frequency, and r p r is the diameter of the transmitting sub-coil. s For the receiving sub-coil wire diameter, I p0 I0 is the rated current of the transmitter sub-coil, and I0 is the rated current corresponding to the initial wire diameter of the transmitter sub-coil. S2: Determine the total number of turns N of the transmitter sub-coil p0 =d p / (2r p The total number of turns N in the receiving sub-coil s0 =d s / (2r s Mutual inductance coefficient M0= V out / (πωI p0 ), and set variable N p1 =N p2 =N s =0, where N p1 N represents the number of turns of the first loop-shaped transmitting coil. p2 N represents the number of turns of the second loop-shaped transmitting coil. s This refers to the number of turns of the receiving sub-coil; S3: Set N p1 =N p1 +1, and determine If the condition is met, proceed to step S7; otherwise, proceed to step S4. S4: Set N p2 =N p2 +1, and determine Is it true? If it is true, then set N. p2 If the value is 0, return to step S3; otherwise, proceed to step S5. S5: Set N s =N s +1, and determine Is it true? If it is true, then set N. s If the value is 0, return to step S4; otherwise, proceed to step S6. S6: Determine M min >M0 and M min / M max Check if <0.95 is true. If true, keep the current solution as a candidate parameter and return to step S5; otherwise, return directly to step S5; where M min M is the minimum mutual inductance value within a predetermined offset angle range under the current parameters. max This represents the maximum mutual inductance value within the predetermined offset angle range under the current parameters. S7: Determine if there are any alternative parameters. If so, select the parameter with the largest mutual inductance value as the current parameter value; otherwise, set... And adjust r p Return to step S2 to redesign. This indicates the recommended adjustment step for the transmitter coil current.

2. The parameter design method for the double U-shaped coupling mechanism according to claim 1, characterized in that, When the transmitting coil is provided with three transmitting sub-coils and the receiving coil is provided with three receiving sub-coils, the parameters of the three transmitting sub-coils are the same and the parameters of the three receiving sub-coils are the same.

3. The double U-shaped coupling mechanism designed according to the parameter design method of the double U-shaped coupling mechanism according to claim 1 or 2, characterized in that, The first arc surface has three transmitting sub-coils distributed circumferentially, and each transmitting sub-coil is provided with a transmitting end mounting base with an arc surface.

4. The double U-shaped coupling mechanism according to claim 3, characterized in that, The second arc surface has three receiving sub-coils distributed circumferentially, and each receiving sub-coil is provided with a receiving end mounting base with an arc surface.

5. The double U-shaped coupling mechanism according to claim 4, characterized in that, The radius of the first arc surface is greater than the radius of the second arc surface. The transmitting sub-coil is disposed on the concave arc surface inside the transmitting end mounting base. The receiving sub-coil is disposed on the convex arc surface outside the receiving end mounting base, and the transmitting sub-coil and the receiving sub-coil are disposed in a one-to-one correspondence.

6. The double U-shaped coupling mechanism according to claim 5, characterized in that, The transmitter mounting base is equipped with an energy transmitting circuit and a transmitter magnetic shielding layer, and the receiver mounting base is equipped with an energy receiving circuit and a receiver shielding layer.

7. The double U-shaped coupling mechanism according to claim 4, 5, or 6, characterized in that, The transmitter mounting base is fixed to the energy transmitting device via a telescopic mechanism, and the receiver mounting base is fixedly connected to the energy receiving device.

8. An underwater constant-voltage wireless charging system, comprising an energy transmitting device and an energy receiving device, characterized in that: The energy transmitting device and the energy receiving device are coupled using the double U-shaped coupling mechanism described in any one of claims 3-7.

9. The underwater constant voltage wireless charging system according to claim 8, characterized in that: The energy transmitting device is equipped with a DC power supply and an inverter module. The inverter module is connected in parallel to three energy transmitting circuits. Each energy transmitting circuit is connected to a transmitting sub-coil. The electrical load of the energy receiving device is powered by the three energy receiving circuits in parallel. Each energy receiving circuit is connected to a receiving sub-coil. The energy transmitting device is further equipped with a transmitting end control module, which is configured with a first communication module and a drive circuit for driving the inverter module. A voltage sampling circuit is also connected to the electrical load, and the voltage sampling circuit is connected to the receiving end control module. A second communication module is configured on the receiving end control module. The transmitting end control module establishes a communication connection with the receiving end control module through the first communication module and the second communication module to receive the voltage status of the electrical load and realize phase shift control of the inverter module.

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