An underwater flash charging station system and flash charging method based on omnidirectional ocean current energy harvesting

Abstract

This invention discloses an underwater flash charging station system and method based on omnidirectional ocean current energy harvesting, belonging to the field of marine new energy utilization and underwater equipment support. The system includes: an omnidirectional ocean current energy generation device with an internal polyhedral substrate, an off-grid energy storage and power supply device, and an underwater flash charging station. The underwater flash charging station is equipped with a wet-plug interface for docking with underwater unmanned equipment and has a built-in high-power flash charging module. The output end of the high-power flash charging module is electrically connected to the wet-plug interface. The high-power flash charging module is configured to instantly release stored electrical energy for high-power rapid charging when the underwater unmanned equipment is connected to the wet-plug interface, and to perform a reverse pulse depolarization operation during the charging process. By utilizing the idle time of the underwater charging station for long-cycle weak energy harvesting and achieving high-power rapid release when the equipment is connected, the system solves the mismatch between ocean current power generation and the fast charging requirements of underwater equipment.

Description

Technical Field

[0001] This application relates to the field of marine new energy utilization and underwater unmanned equipment support technology, specifically to an underwater flash charging station system and flash charging method based on omnidirectional ocean current energy harvesting. Background Technology

[0002] With the continuous advancement of global marine resource development and deep-sea exploration, the deployment of underwater unmanned equipment is increasing year by year. However, the anxiety about the endurance of underwater unmanned equipment remains the core bottleneck limiting its large-scale and long-term operations.

[0003] Ocean currents in the deep sea environment are often characterized by low velocity, variable direction, and complex eddies. Traditional turbine-type hydroelectric generators have strict requirements on the direction and minimum velocity of the water flow, making them difficult to operate effectively in complex and weak ocean current environments. In addition, existing micro-energy harvesting devices are prone to electromagnetic coupling interference when converting weak kinetic energy into electrical energy, resulting in a large amount of energy loss and extremely low actual output power (typically only in the milliwatt to a few watt range).

[0004] Modern underwater unmanned equipment (UAVs) are equipped with large-capacity batteries, requiring extremely high charging power (typically in the kilowatt or even megawatt range). If the traditional method of real-time power generation and direct charging is used, relying on weak ocean currents to charge the UAVs directly, it could take several days or even weeks to fully charge a single device. This prolonged waiting in place would cause the UAVs to lose maneuverability, severely impacting their operational efficiency. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an underwater flash charging station system and flash charging method based on omnidirectional ocean current energy harvesting.

[0006] In a first aspect, the technical solution of the present invention provides an underwater flash charging station system based on omnidirectional ocean current energy harvesting, including an omnidirectional ocean current energy power generation device with an internal polyhedral base, an off-grid energy storage and power supply device, and an underwater flash charging station; The output end of the Wanxiangyang Flow Power Generation Device is electrically connected to the input end of the off-grid energy storage and power supply device, and the output end of the off-grid energy storage and power supply device is electrically connected to the input end of the underwater flash charging station. The underwater flash charging station is equipped with a wet plug-in interface for docking with underwater unmanned equipment, and has a built-in high-power flash charging module. The output end of the high-power flash charging module is electrically connected to the wet plug-in interface.

[0007] The system captures irregular ocean currents through an omnidirectional ocean current energy generation device, and accumulates energy over a long period through off-grid energy storage and power supply devices, which then releases high power instantaneously via an underwater flash charging station. This breaks through the limitation of low real-time power generation in traditional systems and resolves the contradiction between the range anxiety of underwater equipment and the low density of ocean current energy.

[0008] The three components are electrically connected to form an independent module, enabling the flash charging station to be deployed in the vast deep sea without relying on the land power grid, providing an off-grid energy supply node for underwater unmanned equipment.

[0009] As a preferred embodiment of the technical solution of the present invention, the omnidirectional ocean current power generation device includes a fully sealed spherical shell, and a polyhedral base is fixed inside the spherical shell. Each face of the polyhedral substrate is equipped with an anti-electromagnetic coupling universal power generation module.

[0010] The spherical shell, combined with the polyhedral base, enables the power generation device to operate effectively under any ocean current direction, overcoming the technical limitation of traditional impeller-type hydroelectric generators that are sensitive to water flow direction. Arranging the power generation modules on each face of the polyhedron maximizes the number of power generation units and total power output within a limited volume. The fully sealed spherical shell possesses excellent pressure resistance and corrosion resistance, adapting to the high pressure and corrosive environment of the deep sea, thus improving the system's reliability and service life.

[0011] As a preferred embodiment of the present invention, the anti-electromagnetic coupling universal power generation module has a through-hole micro-ceramic central shaft at its center, and the anti-electromagnetic coupling universal power generation module adopts a stator-rotor-rotor-stator sandwich structure, comprising: The first and second induction coil disks are fixedly mounted in parallel on the supports at both ends of the central shaft; A first eccentric pendulum and a second eccentric pendulum are coaxially suspended on the central shaft via independent bearings. The first eccentric pendulum is located between the first induction coil disk and the second induction coil disk, and the second eccentric pendulum is located between the first eccentric pendulum and the second induction coil disk. The first induction coil disk and the second induction coil disk have front coils in the front annular array and side coils in the side array; The first eccentric pendulum and the second eccentric pendulum are arranged back to back, and each has an arc-shaped permanent magnet array on the side facing the front coil.

[0012] Employing a sandwich structure with double-layered coils and two back-to-back pendulums, the two coil layers work in conjunction with two eccentric pendulums to generate electricity, doubling the single-sided power output without increasing the module's footprint. The Hellbeck array possesses the physical characteristic of having no magnetic field on its back side. The two back-to-back eccentric pendulums, rotating coaxially, do not experience magnetic attraction or mutual drag resistance, allowing them to oscillate independently and freely in complex ocean currents, thus improving mechanical energy capture efficiency. The side coils generate an isolation magnetic field perpendicular to the direction of the front magnetic field at the physical gap between the front coils, effectively blocking magnetic flux leakage and alternating magnetic field interference between adjacent front coils from a physical electromagnetic perspective, significantly reducing electromagnetic coupling losses during micro-energy harvesting. Driven by gravity and rotational inertia, the eccentric pendulums are insensitive to ocean current direction, enabling power generation at extremely low current velocities, thus improving the utilization rate of ocean current energy.

[0013] As a preferred embodiment of the technical solution of the present invention, both the first eccentric pendulum and the second eccentric pendulum are equipped with counterweights on their edges.

[0014] As a preferred embodiment of the technical solution of the present invention, it further includes an underwater fixed installation structure; the underwater fixed installation structure includes: a seabed base fixed to the seabed, a support frame fixed to the seabed base, a first pressure-resistant watertight chamber for sealing and accommodating the off-grid energy storage and power supply device, and a second pressure-resistant watertight chamber for sealing and accommodating the underwater flash charging station; the first pressure-resistant watertight chamber and the second pressure-resistant watertight chamber are both fixed to the support frame by fasteners; The spherical shell of the universal ocean current power generation device is fixed on the support frame. The universal ocean current power generation device is electrically connected to the input end of the off-grid energy storage and power supply device in the first pressure-resistant watertight chamber through an external watertight cable. The socket end of the wet plug-in interface is fixedly inserted into the shell of the second pressure-resistant watertight chamber, and the socket end and the shell are watertightly isolated by its own sealing component.

[0015] As a preferred embodiment of the technical solution of the present invention, the off-grid energy storage and power supply device includes an active rectifier circuit, a front-stage boost circuit, and a stepped energy storage circuit connected in sequence. The active rectifier circuit includes an active rectifier bridge chip, and the front-stage boost circuit includes a front-stage boost chip. The stepped energy storage circuit includes a supercapacitor bank and a deep-sea battery bank, with the output terminal of the deep-sea battery bank electrically connected to the input terminal of the underwater flash charging station.

[0016] As a preferred embodiment of the technical solution of the present invention, the stepped energy storage circuit further includes a window comparator, a subsequent step-up / step-down circuit, and a high-power switching transistor; The input terminal of the window comparator is connected across the two ends of the supercapacitor bank to monitor the terminal voltage of the supercapacitor bank; the output terminal of the window comparator is electrically connected to the control electrode of the high-power switching transistor. The output terminal of the supercapacitor bank is electrically connected to the input terminal of the subsequent step-up / step-down circuit; The output terminal of the subsequent step-up / step-down circuit is electrically connected to the input terminal of the high-power switching transistor through a current sampling resistor; the output terminal of the high-power switching transistor is electrically connected to the charging terminal of the deep-sea battery pack through a battery anti-reverse current circuit.

[0017] The subsequent step-up / step-down circuit achieves a constant high current output through a current sampling resistor, ensuring controllable current during tilting and preventing impact damage to the battery. The battery reverse-current protection circuit prevents battery current from flowing back into the supercapacitor bank or the preceding circuit, ensuring safe and stable system operation.

[0018] As a preferred embodiment of the technical solution of the present invention, the high-power flash charging module includes a dual active bridge bidirectional DC-DC converter, a phase shift controller, a voltage sampling circuit, and a current sampling resistor; The dual active bridge bidirectional DC-DC converter includes a primary-side full-bridge inverter module, a high-frequency isolation transformer, and a secondary-side full-bridge rectifier / inverter module. The input terminal of the primary-side full-bridge inverter module is electrically connected to the output terminal of the off-grid energy storage and power supply device, and the output terminal of the primary-side full-bridge inverter module is electrically connected to the primary side of the high-frequency isolation transformer. The secondary side of the high-frequency isolation transformer is electrically connected to the input terminal of the secondary-side full-bridge rectifier / inverter module, and the output terminal of the secondary-side full-bridge rectifier / inverter module is electrically connected to the wet-plug interface. The voltage sampling circuit is connected in parallel to the output terminal of the secondary side full-bridge rectifier / inverter module, and the output terminal of the voltage sampling circuit is electrically connected to the voltage detection input terminal of the phase shift controller. The current sampling resistor is connected in series with the output terminal of the secondary side full-bridge rectifier / inverter module, and the two ends of the current sampling resistor are electrically connected to the current detection input terminal of the phase shift controller. The output terminal of the phase shift controller is electrically connected to the control electrode of the switching transistor of the primary-side full-bridge inverter module and the secondary-side full-bridge rectifier / inverter module, respectively.

[0019] High-frequency isolation transformers provide safe electrical isolation in underwater high-voltage charging scenarios, preventing leakage accidents and ensuring the safety of underwater unmanned equipment and operators.

[0020] As a preferred embodiment of the technical solution of the present invention, the high-power flash charging module further includes a pulse depolarization controller, which is connected to the dual active bridge bidirectional DC-DC converter.

[0021] As a preferred embodiment of the technical solution of the present invention, the pulse depolarization controller includes a low-frequency pulse generator, a depolarization switching transistor, and a transient high-power dissipation resistor; The output terminal of the low-frequency pulse generator is electrically connected to the control electrode of the depolarization switch. The depolarization switch is connected in series with the transient high-power dissipation resistor and then connected between the positive and negative output terminals of the dual active bridge bidirectional DC-DC converter. The output terminal of the low-frequency pulse generator is also electrically connected to the enable terminal of the phase shift controller.

[0022] A pure hardware depolarization circuit is constructed using a low-frequency pulse generator, a depolarization switch, and dissipation resistors. It does not rely on software control, resulting in fast response and high reliability. The output signal of the low-frequency pulse generator simultaneously controls the enable terminals of both the depolarization switch and the phase-shift controller, ensuring that forward charging is completely suspended during reverse discharge pulses and avoiding energy conflicts.

[0023] In response to the situation where some underwater unmanned equipment has hardware limitations against reverse connection and cannot remove reverse discharge permissions through software, this pure hardware controller provides an independent physical discharge circuit to ensure that the depolarization function can be implemented on any device.

[0024] As a preferred embodiment of the technical solution of the present invention, the wet plug-in interface is a wet plug-in watertight connector, including a socket end fixedly disposed on the shell of the second pressure-resistant watertight chamber. The socket end is used to form an electrical connection and a watertight seal when it is plugged into the plug end of an external underwater unmanned device underwater.

[0025] The use of wet-plug watertight connectors allows underwater unmanned equipment to perform plugging and unplugging operations while energized, without needing to surface, significantly improving the continuity and convenience of underwater operations.

[0026] Secondly, the present invention also provides an underwater flash charging method based on omnidirectional ocean current energy harvesting, applied to the underwater flash charging station system described in the first aspect, comprising the following steps: The underwater multi-directional ocean current energy is converted into alternating current using an omnidirectional ocean current energy generator. The alternating current is rectified, and by collecting voltage and current, the maximum power point tracking algorithm is run to stabilize the rectified power and store the power in a stepped energy storage circuit. When an underwater unmanned device is detected to be accessing the system, battery parameters are obtained through the power line carrier communication unit. The target charging voltage is calculated based on the battery parameters, and the target charging voltage is sent to the phase shift controller; The phase-shift controller samples the output voltage and current in real time, and dynamically adjusts the phase-shift angle of the dual active bridge bidirectional DC-DC converter through closed-loop feedback to clamp the output voltage to the target charging voltage and output constant current at the maximum allowable current. At the same time, during the charging process, the phase-shift angle polarity of the dual active bridge bidirectional DC-DC converter is periodically changed, and a reverse discharge pulse is inserted to eliminate concentration polarization on the electrode surface.

[0027] As a further limitation of the technical solution of the present invention, the maximum power point tracking algorithm is implemented using the perturbation-observation method: Each control cycle samples the current input voltage V(k) and current I(k) and calculates the power P(k). It compares the difference ΔP between the current power P(k) and the power P(k-1) of the previous cycle. The direction of voltage disturbance in the next cycle is determined based on the sign of the difference ΔP. By sending a control signal to the front-stage boost chip to dynamically limit the power, the operating point of the Wanxiang Ocean Current Power Generation Device is changed, so that the Wanxiang Ocean Current Power Generation Device always operates at the maximum power output point under the current ocean current conditions.

[0028] MPPT (Maximum Power Point) is implemented using a perturbation-observation method. In each control cycle, voltage and current are sampled to calculate power. The perturbation direction for the next cycle is determined by comparing the current power with that of the previous cycle, allowing the input impedance of the front-end boost chip to dynamically track the internal resistance of the power generation device. This algorithm does not require prior knowledge of ocean current characteristics and can adaptively converge to the maximum power point in the deep-sea environment with randomly varying current velocities, thus improving energy harvesting efficiency.

[0029] As a further limitation of the technical solution of the present invention, the process of inserting a reverse discharge pulse is as follows: During the high-current constant-current charging phase, after every T seconds of high-current charging, the output is stopped for t1 milliseconds and left to stand still. Then, the phase angle polarity of the dual active bridge bidirectional DC-DC converter is changed, and it operates in reverse for t2 milliseconds to extract discharge pulses from the battery to forcibly eliminate concentration polarization on the electrode surface. After the reverse pulse ends, forward high-current charging is immediately resumed.

[0030] This combination of timing parameters can minimize polarization resistance while ensuring charging speed, effectively controlling the temperature rise of the battery during fast charging, avoiding lithium deposition and capacity decay caused by polarization, and extending the service life of underwater unmanned equipment batteries.

[0031] As a further limitation of the technical solution of the present invention, the step of storing electrical energy in the tiered energy storage circuit includes: Real-time monitoring of the terminal voltage of the supercapacitor bank; When the terminal voltage reaches the first threshold, the supercapacitor bank will transfer energy to the deep-sea battery bank. When the terminal voltage is lower than the second threshold, the supercapacitor bank stops energy transfer and continues to store energy.

[0032] The energy storage management controller uses the MPTT algorithm to operate the power generation device at its maximum power point, and then stores energy in the supercapacitor bank after rectification and voltage regulation. The window comparator monitors the terminal voltage in real time, and only triggers the energy storage switching device to transfer energy to the deep-sea battery bank when the voltage reaches a high threshold, and automatically stops when the voltage drops to a low threshold. This achieves the underlying hardware support for trading time for power.

[0033] As a further limitation of the technical solution of the present invention, it also includes safety monitoring and emergency interruption steps: During the charging process, the temperature, water ingress status of the sealed cavity, insulation resistance, power line carrier communication status, and current sampling value are monitored in real time. When any abnormality is detected, such as overheating, water ingress, decreased insulation, abnormal contact resistance, or communication interruption, the PWM drive of the dual active bridge bidirectional DC-DC converter is immediately shut down, the energy storage switching device is disconnected, and the emergency disconnection mechanism is driven to release the locking state, so that the underwater unmanned equipment can be removed from the charging base.

[0034] As can be seen from the above technical solutions, this application has the following advantages: by decoupling ocean current energy harvesting, off-grid energy storage, and fast charging functions, a complete energy chain is constructed. Compared with the traditional real-time power generation and real-time direct charging mode, this system utilizes the long idle period of the underwater charging station for continuous energy harvesting and accumulation, converting milliwatt-level weak ocean current energy into kilowatt-level fast charging capacity for underwater unmanned equipment, breaking down the physical gap between ocean current power generation and the fast charging requirements of underwater equipment. Simultaneously, depolarization control is applied during the charging process, eliminating the concentration polarization internal resistance caused by high-current charging, allowing the long-term accumulated electrical energy to be safely and efficiently injected into the equipment battery in a very short time, ensuring charging speed while extending battery cycle life. Attached Figure Description

[0035] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a diagram showing the overall architecture of an underwater flash charging station system.

[0037] Figure 2 This is a side view of the stator-rotor-rotor-stator sandwich power generation module, where P1 is an eccentric pendulum.

[0038] Figure 3 This is a three-dimensional schematic diagram of an eccentric pendulum and its supporting structure.

[0039] Figure 4 The diagram shows the Heilbeck magnet array for the eccentric pendulum, illustrating the magnetic pole arrangement facing the coil side.

[0040] Figure 5 This is a front view of a single power generation module, where Q1 is the front induction coil and Q2 is the side induction coil.

[0041] Figure 6 This is a circuit diagram for an off-grid energy storage and power supply device.

[0042] Figure 7 This is a timing diagram of pulse depolarization.

[0043] Figure 8 This is the hardware topology diagram of a dual active bridge bidirectional DC-DC converter.

[0044] Figure 9 This is the circuit diagram for a pulse depolarization controller.

[0045] Figure 10 Schematic diagram of the underwater fixed installation structure of the underwater flash charging station system.

[0046] Figure 11 This is a schematic diagram of a polyhedral base.

[0047] Figure 12 This is the control logic diagram of the DAB converter for the high-power flash charging module of the present invention.

[0048] Figure 13 This is a flowchart illustrating the method provided in an embodiment of the present invention.

[0049] In the diagram, 1-submarine base, 2-anchor, 3-counterweight, 4-support frame, 5-omnidirectional ocean current power generation device, 6-first pressure-resistant watertight chamber, 7-second pressure-resistant watertight chamber, 8-socket end, 9-clamp assembly, 10-watertight cable. Detailed Implementation

[0050] To make the purpose, features, and advantages of this application more apparent and understandable, specific embodiments and accompanying drawings will be used to clearly and completely describe the technical solution protected by this application. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this application and in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0052] like Figure 1 As shown, this embodiment of the invention provides an underwater flash charging station system based on omnidirectional ocean current energy harvesting, including an omnidirectional ocean current energy generation device, an off-grid energy storage and power supply device, and an underwater flash charging station; The output end of the Wanxiangyang Flow Power Generation Device is electrically connected to the input end of the off-grid energy storage and power supply device, and the output end of the off-grid energy storage and power supply device is electrically connected to the input end of the underwater flash charging station. The underwater flash charging station is equipped with an underwater wet-plug interface and a high-power flash charging module. The output end of the high-power flash charging module is electrically connected to the underwater wet-plug interface.

[0053] The omnidirectional ocean current energy generation device is deployed underwater to capture multidirectional ocean current energy and convert it into alternating current (AC). An off-grid energy storage and power supply device is connected to the omnidirectional ocean current energy generation device. Through active rectification, maximum power point tracking impedance matching, and voltage stabilization, it converts the extremely unstable and weak AC power into smooth DC power for long-term energy storage. An underwater flash charging station is connected to the off-grid energy storage and power supply device and is equipped with an underwater wet-plug interface and a high-power flash charging module. When underwater unmanned equipment (such as a UUV) is connected to the wet-plug interface, the underwater flash charging station instantly releases the stored energy for high-power rapid charging, and applies depolarization control during the charging process.

[0054] In some embodiments, combined with Figures 1-5 The omnidirectional ocean current power generation device includes a fully sealed spherical shell and a polyhedral substrate (such as...) fixed inside the spherical shell. Figure 11 As shown in the figure, anti-electromagnetic coupling universal power generation modules are installed on each face of the polyhedral substrate. The polyhedral substrate is preferably a regular dodecahedral substrate, and the number of anti-electromagnetic coupling universal power generation modules is 12.

[0055] The anti-electromagnetic coupling universal power generation module adopts a stator-rotor-rotor-stator sandwich structure. Specifically, the anti-electromagnetic coupling universal power generation module includes a first induction coil disk and a second induction coil disk that are fixedly mounted parallel to each other on the supports at both ends of the central shaft; for example... Figure 2 and Figure 3 As shown.

[0056] The first eccentric pendulum P1 and the second eccentric pendulum (another pendulum symmetrically arranged in the figure) are coaxially suspended on the central axis via independent bearings. The first eccentric pendulum is located between the first and second induction coil disks, and the second eccentric pendulum is located between the first eccentric pendulum and the second induction coil disk. The first and second eccentric pendulums are arranged back-to-back, and their centers of gravity are offset from the center of rotation. Each eccentric pendulum is equipped with a high-density tungsten steel counterweight on its edge to increase the moment of inertia and improve the pendulum sensitivity in weak ocean currents.

[0057] like Figure 5 As shown, the first and second induction coil disks have a front coil Q1 in a front annular array and a side coil Q2 in a side array, with the side coil Q2 located at the physical gap between adjacent front coils Q1. During power generation, the high-density magnetic field outside the first and second eccentric pendulums cuts the upper and lower layers of front induction coils respectively, generating double the main current; simultaneously, the side magnets cut the side induction coils, generating induced current. According to Lenz's law, this induced current will induce an isolation magnetic field around the side induction coils, perpendicular to the direction of the front induction coil's magnetic field. This perpendicular isolation magnetic field spatially blocks magnetic flux leakage and alternating magnetic field interference between adjacent front induction coils, virtually eliminating electromagnetic coupling losses from a physical electromagnetics perspective.

[0058] The first and second eccentric pendulums each have an arc-shaped permanent magnet array on the side facing the front coil. This arc-shaped permanent magnet array is an arc-shaped Heilbeck array, such as... Figure 4 As shown, the pendulum is formed by assembling multiple permanent magnets with different magnetization directions into an arc shape, arranged in a spatial phase rotation pattern of 90 degrees. This unique topological arrangement causes the magnetic field lines to superimpose and cancel each other out: on the side closest to the coil disk (working side), the magnetic field lines are highly concentrated, forming an extremely strong sinusoidal magnetic field; while in the middle region between the two pendulums back to back (non-working side), the magnetic field lines cancel each other out, achieving self-shielding. Since there is almost no leakage magnetic flux on the back side of the two pendulums, there is no magnetic attraction or electromagnetic damping drag between them when they swing at high speed on the same axis or swing in opposite directions.

[0059] As the ocean current causes the spherical shell to sway, the first and second eccentric pendulums, under the influence of gravity and rotational inertia, rotate relative to each other around the central axis. The high-density magnetic fields on the outer sides of the two pendulums cut the upper and lower front coils Q1, generating double the main current. Simultaneously, the induced current generated by the magnet cutting the side coil Q2 excites an isolation magnetic field around the side coil Q2, perpendicular to the magnetic field direction of the front coil Q1. This perpendicular isolation magnetic field spatially blocks the leakage of magnetic flux and interference of alternating magnetic fields between adjacent front coils Q1, eliminating electromagnetic coupling losses from a physical electromagnetic perspective.

[0060] like Figure 10 As shown, the underwater flash charging station system also includes an underwater fixed installation structure.

[0061] The underwater fixed installation structure includes: a seabed base 1 fixed to the seabed by anchors 2, a support frame 4 fixed on the seabed base 1, a counterweight block 3 set at the bottom of the support frame 4, a first pressure-resistant watertight chamber 6 for sealing and accommodating the off-grid energy storage and power supply device, and a second pressure-resistant watertight chamber 7 for sealing and accommodating the underwater flash charging station.

[0062] The omnidirectional ocean current power generation device 5 adopts a fully sealed spherical shell and is independently installed outside the first pressure-resistant watertight chamber 6. The omnidirectional ocean current power generation device 5 is electrically connected to the input end of the off-grid energy storage and power supply device inside the first pressure-resistant watertight chamber 6 via an external watertight cable 10.

[0063] The omnidirectional ocean current power generation device 5, the first pressure-resistant watertight chamber 6, and the second pressure-resistant watertight chamber 7 are respectively fixed to the support frame 4 by clamping assemblies 9. Specifically, the clamping assemblies 9 surround and cover the spherical outer shell of the omnidirectional ocean current power generation device 5 and the outer walls of each pressure-resistant watertight chamber, and are fixedly connected to the support frame 4 below by fasteners, thereby reliably confining these devices on the support frame 4.

[0064] The underwater unmanned equipment connects underwater via the plug end of its charging cable to the wet plug-in interface socket end 8 located at the end of the shell of the second pressure-resistant watertight chamber 7, forming a charging circuit.

[0065] To achieve electrical connection and watertight isolation between the inside and outside of the chambers, watertight cable penetrations are installed on the end caps of both the first pressure-resistant watertight chamber 6 and the second pressure-resistant watertight chamber 7. Specifically, one end of the external watertight cable 10 is electrically connected to the output end of the omnidirectional ocean current power generation device 5, and the other end is electrically connected to the input end of the off-grid energy storage and power supply device inside the chamber through the first watertight cable penetration on the end cap of the first pressure-resistant watertight chamber 6. The first watertight cable penetration is sealed to the end cap of the pressure-resistant watertight chamber via a flange.

[0066] The socket end 8 of the wet plug-in interface is fixedly installed on the outside of the end cover of the second pressure-resistant watertight chamber 7. The socket end 8 has its own mounting flange and sealing ring. It is connected to the end cover by fasteners and the sealing ring is pressed to achieve watertight isolation. The contact of the socket end 8 extends into the chamber and is electrically connected to the output end of the high-power flash charging module inside the chamber.

[0067] In this embodiment of the invention, the end caps of the first pressure-resistant watertight chamber 6 and the second pressure-resistant watertight chamber 7 are connected to the cylinder body via flange assemblies. A double O-ring seal is used to achieve waterproof sealing. The seal material is fluororubber or nitrile rubber, and the compression of the seal is controlled between 15% and 30%. The shell material of the pressure-resistant watertight chamber is aluminum alloy 6061 (anodized) or titanium alloy TC1 to balance strength, corrosion resistance, and weight requirements.

[0068] The external watertight cable 10 is a submarine power cable with cross-linked polyethylene insulation, lead sheath, steel wire armor, and a polypropylene fiber outer sheath, model HYJQ41 (excluding optical fiber) or HYJQ41-F (including optical fiber). The cable conductor is a Class 2 tightly stranded round copper conductor conforming to national standards. The insulation is made of ultra-clean cross-linked polyethylene material. The metal sheath is a continuously extruded seamless lead sheath as a radial water-blocking layer. The armor layer is made of hot-dip galvanized low-carbon steel wire or copper wire. The outer sheath is made of polypropylene rope wound and impregnated with asphalt to resist seawater corrosion and mechanical stress during laying.

[0069] The wet-plug interface uses a segmented rubber-plastic wet-plug watertight connector. Both the plug and socket ends are manufactured using integral rubber vulcanization sealing technology: the metal contacts are pre-treated and coated with adhesive, then molded and vulcanized with a rubber elastomer at 180–200°C, ensuring a tight bond between the contacts and the rubber. During mating, the plug and socket utilize the compression deformation generated by the interference fit for drainage and sealing, achieving highly reliable watertightness without the need for O-rings.

[0070] In some embodiments, combined with Figure 1 and Figure 6 The off-grid energy storage and power supply device includes an active rectifier circuit, a pre-stage boost circuit, and a stepped energy storage circuit; the active rectifier circuit includes an active rectifier bridge chip, the pre-stage boost circuit includes a pre-stage boost chip; the stepped energy storage circuit includes a supercapacitor bank and a deep-sea battery bank, and the output terminal of the deep-sea battery bank is electrically connected to the input terminal of the underwater flash charging station.

[0071] The active rectifier bridge chip is the LT4320, which drives a full-bridge rectifier network composed of MOSFETs. The input of the full-bridge rectifier network is connected to the Wanxiangyang Current Power Generation Device (i.e., Figure 6 The generator in the system is electrically connected to its output terminal. A protection device, SMBJ18A, is also connected in series between the output terminal of the omnidirectional ocean current power generation device and the active rectifier circuit for surge suppression. This active rectifier circuit reduces the rectified voltage to below 0.05V, ensuring that the weak ocean current power is not consumed by the rectifier circuit itself.

[0072] The preamplifier boost chip uses the SC8801, and its peripheral circuitry includes an inductor and a feedback resistor network. One end of the inductor is electrically connected to the switch pin of the preamplifier boost chip, and the other end is electrically connected to the output terminal of the preamplifier boost chip. The feedback resistor network includes a first resistor and a second resistor connected in series. One end of the first resistor is electrically connected to the output terminal of the preamplifier boost chip, and the other end of the first resistor is connected to one end of the second resistor and then to the feedback pin of the preamplifier boost chip. The other end of the second resistor is grounded. The preamplifier boost circuit converts the actively rectified pulsating DC power into a stable DC charging voltage output. The output terminal of the preamplifier boost chip is electrically connected to the input terminal of the stepped energy storage circuit through the bus reverse current protection chip LM74670-Q1.

[0073] The stepped energy storage circuit also includes a window comparator, a subsequent buck-boost circuit, and a high-power switching transistor. The window comparator uses a TLV6700, with its input connected across the supercapacitor bank to monitor its terminal voltage. The output of the window comparator is electrically connected to the gate of the high-power switching transistor. The output of the supercapacitor bank is electrically connected to the input of the subsequent buck-boost circuit. The subsequent buck-boost circuit includes the SC8801 buck-boost chip and its peripheral circuitry. The output of the subsequent buck-boost circuit is electrically connected to the drain of the high-power switching transistor via a current sampling resistor. The source of the high-power switching transistor is electrically connected to the charging terminal of the deep-sea battery pack via a reverse-current protection circuit. The reverse-current protection circuit includes the LM5050-1 reverse-current protection chip. Each individual capacitor is connected in parallel with an overvoltage protection circuit based on the TLV431 equalization chip.

[0074] The working process of the stepped energy storage circuit is as follows: The stable DC power output from the front-stage boost circuit is first injected into the supercapacitor bank for accumulation. The TLV6700 window comparator monitors the terminal voltage of the supercapacitor bank in real time. When the terminal voltage slowly accumulates to the set high threshold (e.g., 15V), the window comparator outputs a high level, turning on the high-power switching transistor. The supercapacitor bank then transfers energy to the deep-sea battery bank in constant current mode via the subsequent boost / buck circuit. When the terminal voltage drops to the low threshold (e.g., 12V), the window comparator outputs a low level, turning off the high-power switching transistor. The supercapacitor bank resumes energy storage, realizing stepped energy storage with incremental accumulation.

[0075] In some embodiments, the off-grid energy storage and power supply device further includes an energy storage management controller, which is electrically connected to the active rectifier circuit and the front-stage boost circuit, respectively. The energy storage management controller is used to sample the voltage and current at the output of the active rectifier circuit, run the maximum power point tracking algorithm, and dynamically adjust the output of the front-stage boost circuit by sending a dynamic power limiting control signal to the front-stage boost circuit, so that the omnidirectional ocean current energy power generation device always operates at the maximum power output point under the current ocean current conditions. The omnidirectional ocean current power generation device, acting as a miniature generator, first suppresses surges through protective devices before entering an active rectifier circuit composed of active rectifier chips. This active rectifier circuit employs a full-bridge active rectifier structure composed of ultra-low on-resistance MOSFETs. By real-time detection of the zero-crossing point of the AC input, it precisely controls the synchronous switching on and off of the MOSFETs, significantly reducing the rectified voltage drop to below 0.05V (millivolt level), ensuring that the weak ocean current energy is not consumed by the rectifier circuit itself.

[0076] The rectified pulsating DC power is input to the front-end boost circuit. The energy storage management controller samples the voltage and current at the output of the active rectifier circuit, runs the maximum power point tracking algorithm, and dynamically adjusts the output of the front-end boost circuit by sending a dynamic power limiting control signal to the front-end boost circuit, so that the omnidirectional ocean current energy generation device always operates at the maximum power output point under the current ocean current conditions.

[0077] Whether the input voltage is extremely low due to weak ocean currents (operating in boost mode) or the input voltage spikes dramatically due to strong ocean currents (seamlessly switching to buck mode), the front-end boost circuit can chop and smooth it, outputting a stable DC bus voltage.

[0078] In some embodiments, such as Figure 1 , Figure 7 , Figure 8 , Figure 9 As shown, the high-power flash charging module of the underwater flash charging station includes a dual active bridge bidirectional DC-DC converter, a phase shift controller, a voltage sampling circuit, a current sampling resistor, and a pulse depolarization controller.

[0079] The dual active bridge bidirectional DC-DC converter includes a primary-side full-bridge inverter module (consisting of 4 switching transistors), a high-frequency isolation transformer, and a secondary-side full-bridge rectifier / inverter module (consisting of 4 switching transistors). The input of the primary-side full-bridge inverter module is electrically connected to the output of the off-grid energy storage and power supply device (i.e., the output of the deep-sea battery pack), and the output of the primary-side full-bridge inverter module is electrically connected to the primary side of the high-frequency isolation transformer T. The secondary side of the high-frequency isolation transformer T is electrically connected to the input of the secondary-side full-bridge rectifier / inverter module, and the output of the secondary-side full-bridge rectifier / inverter module is electrically connected to a wet-swap interface.

[0080] The voltage sampling circuit is connected in parallel to the output terminal of the secondary side full-bridge rectifier / inverter module, and the output terminal of the voltage sampling circuit is electrically connected to the voltage detection input terminal of the phase shift controller. The current sampling resistor is connected in series with the output terminal of the secondary side full-bridge rectifier / inverter module, and the two ends of the current sampling resistor are electrically connected to the current detection input terminal of the phase shift controller. The phase-shift controller, whose output is electrically connected to the control electrodes of the switching transistors of the primary-side full-bridge inverter module and the secondary-side full-bridge rectifier / inverter module, is used to output a PWM wave to adjust the phase shift angle. By adjusting the phase shift angle of the switching transistors, the output voltage and current are controlled. A current sampling resistor is connected in series at the output of the dual active-bridge bidirectional DC-DC converter, and its two ends are electrically connected to the current detection input of the phase-shift controller. A voltage sampling circuit is connected in parallel at the output of the dual active-bridge bidirectional DC-DC converter, and its output is electrically connected to the voltage detection input of the phase-shift controller. The phase-shift controller samples the output voltage and current in real time, and by dynamically adjusting the phase shift angle between the leading and lagging bridge arms, changes the effective pulse width of the primary side of the high-frequency isolation transformer T, precisely clamping the output voltage to the target value with a millisecond-level response speed and maintaining a constant current output.

[0081] The pulse depolarization controller includes a low-frequency pulse generator, a depolarization switch Qq, and a transient high-power dissipation resistor Rq. The low-frequency pulse generator can be a 555 timer, and its output is connected to the enable terminal of the subsequent buck-boost converter chip. The output of the low-frequency pulse generator is electrically connected to the control terminal of the depolarization switch Qq. The depolarization switch Qq and the transient high-power dissipation resistor Rq are connected in series between the positive and negative output terminals of the dual active bridge bidirectional DC-DC converter. The output of the low-frequency pulse generator is also electrically connected to the enable terminal of the phase-shift controller.

[0082] The working process of the pulse depolarization controller is as follows: Figure 7 As shown: During the high-current constant-current charging phase, the low-frequency pulse generator periodically outputs a high-level pulse signal. This high-level pulse signal is sent to the enable terminal of the phase-shift controller, momentarily pausing the forward charging output of the dual active bridge bidirectional DC-DC converter; simultaneously, it drives the depolarization switch to turn on, enabling the battery of the underwater unmanned equipment to form an instantaneous physical discharge circuit through the transient high-power dissipation resistor, generating a brief reverse discharge pulse. This reverse pulse forcibly disperses the lithium-ion concentration gradient accumulated on the electrode surface from an electrochemical perspective, eliminating polarization resistance. After the high-level pulse ends, the phase-shift controller resumes operation, and the dual active bridge bidirectional DC-DC converter immediately resumes forward high-current charging.

[0083] In some embodiments, the high-power flash charging module also includes a flash charging controller. After the underwater unmanned equipment (UUV) docks and completes the wet-plug interface docking, the flash charging controller sends a handshake request to the UUV via a power line carrier communication unit. The power line carrier communication unit communicates with the UUV's battery management system by superimposing a high-frequency carrier signal on the DC power line, and reads battery parameters in real time, including the current battery pack voltage, the maximum allowable charging current, and the real-time temperature of the cells. Simultaneously, the flash charging controller issues control commands to the UUV's battery management system to enable bidirectional charging and discharging permissions or bypass the reverse polarity protection diode, opening a physical channel for subsequent reverse depolarization operations.

[0084] The flash charge controller calculates the target output voltage based on the read battery voltage and cable impedance. Here, the target output voltage = battery voltage + cable voltage drop compensation value, and sends the target value to the phase shift controller.

[0085] The phase-shift controller receives the target output voltage set by the flash-charge controller and samples the output voltage and current in real time. Based on the sampled output voltage and current, the phase-shift controller dynamically adjusts the phase shift angle of the switching transistors of the dual active bridge bidirectional DC-DC converter through closed-loop feedback (i.e., dynamically adjusts the phase shift angle between the leading and lagging bridge arms, changing the effective pulse width of the transformer primary side), precisely clamping the output voltage to the target value with a millisecond-level response speed, and outputting a constant current at the maximum allowable current. This mechanism ensures that the output voltage always matches the battery voltage, directly bypassing the buck circuit inside the power-consuming equipment, directly supplying power to the battery cell, and greatly eliminating heat generation at the equipment end. The control logic of the dual active bridge bidirectional DC-DC converter is as follows: Figure 12 As shown.

[0086] During the high-current constant-current charging phase, severe concentration polarization occurs due to ion accumulation inside the battery. The pulse depolarization controller executes precise periodic timing: after every T seconds of high-current charging, it stops outputting for a rest period of t1 milliseconds, then changes the phase shift angle polarity of the dual active bridge bidirectional DC-DC converter, reversing the operation for t2 milliseconds to extract a brief discharge pulse from the battery. This extremely short reverse pulse forcibly disperses the lithium-ion concentration gradient accumulated on the electrode surface at the electrochemical level, eliminating polarization resistance, and then immediately resumes forward high-current charging.

[0087] To achieve the aforementioned reverse pulse operation, the flash charge controller sends control commands to the battery management system of the underwater unmanned equipment via the power line carrier communication unit during the charging handshake phase. This enables bidirectional charging and discharging permissions and bypasses the reverse connection protection diode, providing a physical path for reverse current. Simultaneously, during the charging process, the flash charge controller synchronously sends depolarization status signals to the battery management system at a set periodic sequence to prevent accidental triggering of over-discharge protection during the reverse pulse period.

[0088] Through the combination of the above software configuration and phase angle polarity reversal, the flash charging station can safely and without damage inject the electrical energy accumulated over several weeks into the underwater unmanned equipment in a short period of time, completing a closed loop of exchanging time for power.

[0089] In some embodiments, the underwater wet-plug interface uses a wet-plug watertight connector, including a socket end fixedly mounted on the underwater flash charging station housing and a plug end located at the end of the charging cable of the underwater unmanned equipment. The socket end and plug end form an electrical connection and a watertight seal when inserted underwater. The underwater wet-plug interface uses existing watertight connectors.

[0090] The working process of this invention is as follows: The omnidirectional ocean current energy generation device captures weak ocean currents in multiple directions and converts them into alternating current (AC). This AC is then converted into pulsating direct current (DC) by an active rectifier circuit, and further converted into stable DC by a pre-stage boost circuit. Finally, it is stored in a deep-sea battery bank through a stepped energy storage circuit in a tiered manner. When no underwater unmanned equipment is connected, the omnidirectional ocean current energy generation device continues to operate, continuously replenishing the deep-sea battery bank with power, achieving long-term energy storage.

[0091] Once the underwater unmanned equipment is moored and connected to the wet-plug interface, the high-power flash charging module begins operation. The current detection input of the phase-shift controller (e.g., a dedicated phase-shift full-bridge controller UCC28950) is electrically connected to both ends of the current sampling resistor, and its voltage detection input is electrically connected to the output of the voltage sampling circuit. The comparator and PWM (Pulse Width Modulation) generator built into the phase-shift controller output a PWM wave based on the comparison between the sampled value and the set value, adjusting the phase shift angle of the primary and secondary switching transistors, thereby changing the converter's output voltage. It should be noted that adjusting the phase shift angle by sampling the output voltage and current to stabilize the output is a well-known closed-loop control technique in the art. Simultaneously, the pulse depolarization controller periodically generates reverse discharge pulses to eliminate the battery's polarization internal resistance.

[0092] Through the above structure, the present invention can safely and without damage inject electrical energy accumulated over weeks or even months into underwater unmanned equipment in a very short time, thus completely realizing a closed loop of exchanging time for power.

[0093] In some embodiments, the underwater flash charging station is equipped with an insulation monitoring unit, a temperature sensor, a pressure sensor, and an emergency disconnection mechanism.

[0094] Before charging begins, the flash charge controller first executes a low-voltage pre-charge process to verify polarity and detects the insulation resistance of the positive and negative busbars to the seawater environment through the insulation monitoring unit. When the insulation resistance is lower than a preset threshold, the charging process is prohibited and an alarm is issued.

[0095] During charging, a temperature sensor monitors the temperature at the plug terminals in real time, a pressure sensor monitors the water ingress status of the sealed cavity in real time, an insulation monitoring unit continuously monitors the insulation resistance, a power line carrier communication unit monitors the communication status, and a current sampling resistor monitors the output current. When any of the following abnormal conditions are detected: over-temperature, water ingress, insulation failure, communication interruption, or abnormal current sampling value, the flash charge controller immediately shuts down the PWM drive of the dual active bridge bidirectional DC-DC converter, disconnects the energy storage switching device in the stepped energy storage circuit, and simultaneously drives the emergency disconnect mechanism to physically release the locking state, allowing the underwater unmanned equipment to detach from the wet plug interface by its own buoyancy or external force.

[0096] After charging is complete, the system first reduces the output current of the dual active bridge bidirectional DC-DC converter to zero, then performs a reverse depolarization stop operation, discharges residual voltage and re-checks insulation at the port, and releases the mechanical locking mechanism after passing the re-check, allowing the underwater unmanned equipment to detach from the charging base.

[0097] Through the above docking, sealing and protection processes, the underwater flash charging station can maintain a stable electrical connection and controllable safety boundaries in high-pressure, low-temperature, conductive seawater environments.

[0098] like Figure 13 As shown, this embodiment of the invention also provides an underwater flash charging method based on omnidirectional ocean current energy harvesting, applied to the underwater flash charging station system described in the above embodiment, including the following steps: S1. Use an omnidirectional ocean current energy generator to convert underwater multidirectional ocean current energy into alternating current; When the ocean current flows past the omnidirectional ocean current power generation device, the spherical outer shell sways with the current. Due to the vertical force of gravity and rotational inertia, the first and second eccentric pendulums in each power generation module undergo relative rotational cutting motion between two layers of induction coil disks. The two eccentric pendulums are positioned back-to-back, each with a permanent magnet arranged in an arc-shaped Hellbeck array on its side facing the coil disk, concentrating the magnetic field lines on one side into the air gap on the working side. The high-density magnetic field on the outer side of the eccentric pendulum cuts the front induction coil to generate an induced electromotive force, while the side magnets cut the side induction coil to generate an auxiliary induced electromotive force, together forming an alternating current output.

[0099] Because deep ocean currents are characterized by low velocity and variable direction, the alternating current output by the power generation device has the characteristics of wide bandwidth, wide amplitude, and extreme instability. Its voltage may fluctuate wildly between 1V and 30V, and its frequency also changes irregularly with the ocean current.

[0100] S2. The alternating current is rectified. By collecting voltage and current, the maximum power point tracking algorithm is run to stabilize the rectified power and store the power in the stepped energy storage circuit. The AC power output from the generator first undergoes surge suppression by protection devices, and then enters an active rectifier circuit composed of an active rectifier chip. This active rectifier circuit employs a full-bridge active rectifier structure composed of ultra-low on-resistance MOSFETs. A dedicated comparator chip detects the zero-crossing point of the AC input in real time, precisely controlling the synchronous switching on and off of the MOSFETs. Traditional diode rectification has a voltage drop of approximately 0.7V, which can consume weak ocean current energy. The active rectifier circuit used in this application significantly reduces the rectified voltage drop to below 0.05V, ensuring that the weak ocean current energy is not consumed by the rectifier circuit itself. The actively rectified energy becomes pulsating DC power, which is input to the subsequent pre-amplifier boost chip.

[0101] The energy storage management controller is electrically connected to the output of the active rectifier circuit and the control terminal of the front-stage boost converter chip. The energy storage management controller samples the voltage and current at the output of the active rectifier circuit, runs a maximum power point tracking algorithm, and dynamically adjusts the output of the front-stage boost converter chip by sending a dynamic power limiting control signal.

[0102] Specifically, the maximum power point tracking algorithm is implemented using the perturbation-observation method, and its execution flow is as follows: In each control cycle, the energy storage management controller samples the current input voltage V(k) and current I(k), and calculates the current power P(k) = V(k) × I(k). It reads the power value P(k-1) saved from the previous cycle and calculates the power difference ΔP = P(k) - P(k-1). It also reads the disturbance direction Dir(k-1) from the previous cycle.

[0103] Energy storage management controller executes decision logic: If ΔP>0, it indicates that the previous disturbance increased the power and the direction of the disturbance was correct. The current period maintains the same direction of the disturbance: Dir(k)=Dir(k-1); If ΔP < 0, it indicates that the previous disturbance reduced the power and the disturbance direction was wrong. The current period reverses the disturbance direction: Dir(k) = -Dir(k-1); If ΔP = 0, the original perturbation direction remains unchanged.

[0104] Based on the decision results, the energy storage management controller sends a dynamic power limiting control signal to the front-stage boost chip, changing the operating point of the power generation device. Whether the input voltage is extremely low due to weak ocean currents (the front-stage boost chip operates in boost mode) or the input voltage spikes dramatically due to strong ocean currents (seamlessly switching to buck mode), the front-stage boost chip can chop and smooth the voltage, outputting a stable DC bus voltage.

[0105] Through iterative convergence of the above-mentioned perturbation observation method, the equivalent load impedance at the input of the front-end boost chip always oscillates slightly around the equivalent internal resistance of the power generation device, achieving dynamic impedance matching and ensuring that the omnidirectional ocean current power generation device always operates at the maximum power output point under the current ocean current conditions.

[0106] The DC bus voltage output from the front-end boost chip is injected into the supercapacitor bank after passing through the bus reverse-current protection chip. The bus reverse-current protection chip ensures that the supercapacitor bank's power will not flow back into the front-end circuit when there is no power generation. Each supercapacitor cell is connected in parallel with an overvoltage protection circuit based on an equalization chip (such as TLV431). When the voltage of a cell exceeds a set value, the equalization chip activates the shunt circuit to prevent overcharging of the cell and ensure the long-term safety of the supercapacitor bank.

[0107] A window comparator monitors the terminal voltage of the supercapacitor bank in real time. The comparator has two comparison points: a high threshold and a low threshold. When the terminal voltage of the supercapacitor bank slowly rises to the high threshold, the comparator outputs a switching signal, triggering the energy storage switch to close. The supercapacitor bank then instantly releases energy to the deep-sea battery bank in a constant current mode. Due to the low internal resistance of the supercapacitor bank, it can instantly release a large current, overcoming the physical limitation that weak ocean currents cannot provide sufficient current to directly break down the internal resistance of large-capacity batteries for effective charging.

[0108] When the terminal voltage of the supercapacitor bank drops to a low threshold, the window comparator outputs a shutdown signal, triggering the energy storage switching device to shut down. The supercapacitor bank is then disconnected from the deep-sea battery bank and energy storage resumes.

[0109] The above process repeats itself to achieve the storage and retrieval of energy: the weak electrical energy collected over a long period of time is accumulated into a block and then instantly transferred to the deep-sea battery pack.

[0110] S3. When an underwater unmanned device is detected to be accessing the system, battery parameters are obtained through the power line carrier communication unit. Once the underwater unmanned equipment (such as UUV) locates the charging station using acoustic positioning or navigation systems, completes physical docking, and inserts into the wet plug interface, the system switches to working mode.

[0111] The flash charge controller sends a handshake request to the underwater unmanned equipment via the power line carrier communication unit. The power line carrier communication unit communicates with the battery management system of the underwater unmanned equipment by superimposing a high-frequency carrier signal on the DC power line, and reads battery parameters in real time, including: the current battery pack voltage Vbat, the maximum allowable charging current Imax (usually expressed as a charging rate, such as 150A for 3C), and the real-time temperature of the battery cells.

[0112] Simultaneously, the flash charge controller sends control commands to the battery management system of the underwater unmanned equipment to enable bidirectional charging and discharging permissions. For underwater unmanned equipment with a reverse connection protection diode in its hardware, the flash charge controller instructs the battery management system to close the corresponding bypass switch, short-circuiting the reverse connection protection diode and providing a physical path for subsequent reverse discharge pulses.

[0113] S4. Calculate the target charging voltage based on the battery parameters, and send the target charging voltage to the phase shift controller; The flash charge controller calculates the voltage drop compensation value ΔV based on the read battery voltage Vbat and the cable impedance. The cable impedance includes the contact resistance of the wet-plug interface and the line resistance of the cable; this impedance value can be pre-calibrated through testing and stored in the flash charge controller. The flash charge controller sets the target output voltage Vout = Vbat + ΔV.

[0114] The flash charge controller sends the target output voltage value to the phase shift controller.

[0115] S5. The phase-shift controller samples the output voltage and current in real time, and dynamically adjusts the phase-shift angle of the dual active bridge bidirectional DC-DC converter through closed-loop feedback to clamp the output voltage to the target charging voltage and output constant current at the maximum allowable current. At the same time, during the charging process, the phase-shift angle polarity of the dual active bridge bidirectional DC-DC converter is periodically changed, and a reverse discharge pulse is inserted to eliminate the concentration polarization on the electrode surface.

[0116] The phase-shift controller (such as the UCC28950 chip or DSP) receives the target output voltage value set by the flash charge controller and samples the output voltage and output current of the dual active bridge bidirectional DC-DC converter in real time.

[0117] The dual active bridge bidirectional DC-DC converter adopts a phase-shifted full-bridge topology and mainly consists of a primary-side full-bridge inverter module (four switching transistors), a high-frequency isolation transformer, and a secondary-side full-bridge rectifier / inverter module. Its input terminal is electrically connected to the deep-sea battery pack, and its output terminal is electrically connected to the wet-plug interface.

[0118] The phase-shift controller dynamically adjusts the phase shift angle between the leading and lagging arms in the primary-side full-bridge inverter module based on the error between the sampled output voltage and the target output voltage through closed-loop feedback. Adjusting the phase shift angle changes the effective pulse width on the primary side of the high-frequency transformer, thereby altering the output voltage.

[0119] The specific control logic is as follows: During the initial charging phase, the battery voltage of the underwater unmanned equipment is low. The phase shift controller uses the maximum allowable current Imax as the control target and adjusts the phase shift angle to stabilize the output current at Imax.

[0120] As the battery voltage gradually increases, when the output voltage reaches the target value Vout, the phase shift controller switches to constant voltage control, adjusts the phase shift angle to stabilize the output voltage at Vout, and the output current naturally decreases as the battery charges.

[0121] The phase-shift controller completes the aforementioned closed-loop regulation with a millisecond-level response speed, precisely clamping the output voltage to the target value and outputting a constant current at the maximum allowable current. This mechanism ensures that the output voltage always matches the battery voltage, directly bypassing the buck circuit inside the underwater unmanned equipment and directly supplying power to the battery cell, greatly reducing heat generation at the equipment end.

[0122] The flash charge controller reads the battery voltage changes in real time at a frequency of 100Hz and dynamically updates the target output voltage value to ensure that the output voltage always rises with the battery voltage.

[0123] During the high-current constant-current charging stage, lithium ions migrate rapidly inside the battery and accumulate on the electrode surface to form a concentration polarization layer, which increases the polarization resistance, leading to a decrease in charging efficiency and battery heating.

[0124] The pulse depolarization controller executes precise periodic timing, such as Figure 8 As shown: During each T-second high-current charge, the phase-shift controller maintains a positive phase-shift angle to continuously charge the battery with the maximum allowable current Imax. At the end of T seconds, the flash-charge controller stops the output of the dual active-bridge bidirectional DC-DC converter for t1 milliseconds. This resting phase is used to initially release part of the ion concentration gradient on the electrode surface. After the resting period, the flash-charge controller instantly changes the phase-shift angle polarity of the phase-shift controller, controlling the dual active-bridge bidirectional DC-DC converter to operate in reverse for t2 milliseconds. At this time, energy flows in reverse from the underwater unmanned equipment battery to the charging station side, extracting a brief discharge pulse from the battery.

[0125] The reverse discharge pulse forcibly disperses the lithium-ion concentration gradient accumulated on the electrode surface at the electrochemical level, eliminating concentration polarization resistance. Since bidirectional charge / discharge capability is enabled in S3 and the reverse connection protection diode is bypassed, reverse current can flow smoothly.

[0126] After the reverse pulse ends, the flash charge controller immediately restores the phase shift angle polarity to positive and continues charging with a large current Imax.

[0127] Repeat the above steps until charging is complete. This cycle depolarization mechanism can minimize polarization resistance while ensuring charging speed, keeping the battery temperature rise within a reasonable range during fast charging and effectively avoiding lithium deposition and capacity decay caused by polarization.

[0128] This embodiment further adds security monitoring and emergency shutdown steps, as detailed below: Before starting charging, perform the following steps: Low-voltage pre-charge: Use a very small current (e.g., 0.1A) to pre-charge for a few milliseconds to verify that the positive and negative polarities are correct and that the plug and socket are making good contact.

[0129] Insulation detection: The insulation monitoring unit detects the insulation resistance of the positive and negative busbars to the seawater environment. If the insulation resistance is lower than a preset threshold, the charging process is prohibited and an alarm is issued.

[0130] During the charging process, the system monitors the safety parameters in Table 1 in real time at a frequency of no less than 10Hz.

[0131] Table 1: Safety Parameter Table

[0132] When any of the above abnormal situations are detected, the flash charge controller immediately executes a Level 3 emergency response: Level 1: Immediately shut down the PWM drive of the dual active bridge bidirectional DC-DC converter and cut off the power output; Second stage: Disconnect the energy storage switching device, cut off the downstream power circuit, and prevent the battery from reverse discharging; Level 3: Drive the emergency disconnect mechanism to physically release the locking state, enabling the underwater unmanned equipment to detach from the wet plug-in interface by its own buoyancy or external force.

[0133] When the battery voltage reaches the full charge threshold or a charging completion command is received from the device's BMS, the normal exit process is executed: The charging current is gradually reduced to zero, a reverse depolarization stop operation is performed, residual voltage is discharged from the port, insulation is re-checked, and the emergency disconnect mechanism is driven to physically release the locking state, so that the underwater unmanned equipment can detach from the wet plug interface by its own buoyancy or external force.

[0134] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An underwater flash charging station system based on omnidirectional ocean current energy harvesting, characterized in that, It includes an omnidirectional ocean current power generation device with a polyhedral base, an off-grid energy storage and power supply device, and an underwater flash charging station; The output end of the Wanxiangyang Flow Power Generation Device is electrically connected to the input end of the off-grid energy storage and power supply device, and the output end of the off-grid energy storage and power supply device is electrically connected to the input end of the underwater flash charging station. The underwater flash charging station is equipped with a wet plug-in interface for docking with underwater unmanned equipment, and has a built-in high-power flash charging module. The output end of the high-power flash charging module is electrically connected to the wet plug-in interface.

2. The underwater flash charging station system based on omnidirectional ocean current energy harvesting according to claim 1, characterized in that, The omnidirectional ocean current power generation device includes a fully sealed spherical shell, and a polyhedral base is fixed inside the spherical shell; Each face of the polyhedral substrate is equipped with an anti-electromagnetic coupling universal power generation module. The anti-electromagnetic coupling universal power generation module has a through-center shaft at its center. The anti-electromagnetic coupling universal power generation module adopts a stator-rotor-rotor-stator sandwich structure, including: The first and second induction coil disks are fixedly mounted in parallel on the supports at both ends of the central shaft; A first eccentric pendulum and a second eccentric pendulum are coaxially suspended on the central shaft via independent bearings. The first eccentric pendulum is located between the first induction coil disk and the second induction coil disk, and the second eccentric pendulum is located between the first eccentric pendulum and the second induction coil disk. The edges of both the first eccentric pendulum and the second eccentric pendulum are equipped with counterweights. The front circular array of the first and second induction coil disks has front coils, and the side array has side coils. The first eccentric pendulum and the second eccentric pendulum are arranged back to back, and each has an arc-shaped permanent magnet array on the side facing the front coil.

3. The underwater flash charging station system based on omnidirectional ocean current energy harvesting according to claim 1, characterized in that, It also includes an underwater fixed installation structure, which includes: a seabed base (1) fixed to the seabed, a support frame (4) fixed to the seabed base (1), a first pressure-resistant watertight chamber (6) for sealing and accommodating off-grid energy storage and power supply devices, and a second pressure-resistant watertight chamber (7) for sealing and accommodating underwater flash charging stations; the first pressure-resistant watertight chamber (6) and the second pressure-resistant watertight chamber (7) are both fixed to the support frame (4) by fasteners; The spherical shell of the universal ocean current power generation device (5) is fixed on the support frame (4), and the universal ocean current power generation device (5) is electrically connected to the input end of the off-grid energy storage and power supply device in the first pressure-resistant watertight chamber (6) through an external watertight cable (10). The socket end (8) of the wet plug-in interface is fixedly installed on the shell of the second pressure-resistant watertight chamber (7), and the socket end (8) and the shell are watertightly isolated by its own sealing component.

4. The underwater flash charging station system based on omnidirectional ocean current energy harvesting according to claim 1, characterized in that, The off-grid energy storage and power supply device includes an active rectifier circuit, a front-stage boost circuit, and a stepped energy storage circuit that are connected in sequence. The active rectifier circuit includes an active rectifier bridge chip, and the front-stage boost circuit includes a front-stage boost chip. The stepped energy storage circuit includes a supercapacitor bank and a deep-sea battery bank, with the output terminal of the deep-sea battery bank electrically connected to the input terminal of the underwater flash charging station. The stepped energy storage circuit also includes a window comparator, a subsequent buck-boost circuit, and a high-power switching transistor. The input terminal of the window comparator is connected across the two ends of the supercapacitor bank to monitor the terminal voltage of the supercapacitor bank; the output terminal of the window comparator is electrically connected to the control electrode of the high-power switching transistor. The output terminal of the supercapacitor bank is electrically connected to the input terminal of the subsequent step-up / step-down circuit; The output terminal of the subsequent step-up / step-down circuit is electrically connected to the input terminal of the high-power switching transistor through a current sampling resistor; the output terminal of the high-power switching transistor is electrically connected to the charging terminal of the deep-sea battery pack through a battery anti-reverse current circuit.

5. The underwater flash charging station system based on omnidirectional ocean current energy harvesting according to claim 4, characterized in that, The high-power flash charging module includes a dual active bridge bidirectional DC-DC converter, a phase shift controller, a voltage sampling circuit, and a current sampling resistor; The dual active bridge bidirectional DC-DC converter includes a primary-side full-bridge inverter module, a high-frequency isolation transformer, and a secondary-side full-bridge rectifier / inverter module. The input terminal of the primary-side full-bridge inverter module is electrically connected to the output terminal of the off-grid energy storage and power supply device, and the output terminal of the primary-side full-bridge inverter module is electrically connected to the primary side of the high-frequency isolation transformer. The secondary side of the high-frequency isolation transformer is electrically connected to the input terminal of the secondary-side full-bridge rectifier / inverter module, and the output terminal of the secondary-side full-bridge rectifier / inverter module is electrically connected to the wet-plug interface. The voltage sampling circuit is connected in parallel to the output terminal of the secondary side full-bridge rectifier / inverter module, and the output terminal of the voltage sampling circuit is electrically connected to the voltage detection input terminal of the phase shift controller. The current sampling resistor is connected in series with the output terminal of the secondary side full-bridge rectifier / inverter module, and the two ends of the current sampling resistor are electrically connected to the current detection input terminal of the phase shift controller. The output terminal of the phase shift controller is electrically connected to the control electrode of the switching transistor of the primary-side full-bridge inverter module and the secondary-side full-bridge rectifier / inverter module, respectively.

6. The underwater flash charging station system based on omnidirectional ocean current energy harvesting according to claim 5, characterized in that, The high-power flash charging module also includes a pulse depolarization controller, which is connected to the dual active bridge bidirectional DC-DC converter. The pulse depolarization controller includes a low-frequency pulse generator, a depolarization switching transistor, and a transient high-power dissipation resistor; The output terminal of the low-frequency pulse generator is electrically connected to the control electrode of the depolarization switch. The depolarization switch is connected in series with the transient high-power dissipation resistor and then connected between the positive and negative output terminals of the dual active bridge bidirectional DC-DC converter.

7. An underwater flash charging method based on omnidirectional ocean current energy harvesting, characterized in that, The underwater flash charging station system described in claim 5 includes the following steps: The underwater multi-directional ocean current energy is converted into alternating current using an omnidirectional ocean current energy generator. The alternating current is rectified, and by collecting voltage and current, the maximum power point tracking algorithm is run to stabilize the rectified power and store the power in a stepped energy storage circuit. When an underwater unmanned device is detected to be accessing the system, battery parameters are obtained through the power line carrier communication unit. The target charging voltage is calculated based on the battery parameters, and the target charging voltage is sent to the phase shift controller; The phase-shift controller samples the output voltage and current in real time, and dynamically adjusts the phase-shift angle of the dual active bridge bidirectional DC-DC converter through closed-loop feedback to clamp the output voltage to the target charging voltage and output constant current at the maximum allowable current. At the same time, during the charging process, the phase-shift angle polarity of the dual active bridge bidirectional DC-DC converter is periodically changed, and a reverse discharge pulse is inserted to eliminate concentration polarization on the electrode surface.

8. The underwater flash charging method based on omnidirectional ocean current energy harvesting according to claim 7, characterized in that, The maximum power point tracking algorithm is implemented using the perturbation-observation method. Each control cycle samples the current input voltage V(k) and current I(k) and calculates the power P(k). It compares the difference ΔP between the current power P(k) and the power P(k-1) of the previous cycle. The direction of voltage disturbance in the next cycle is determined based on the sign of the difference ΔP. By sending a control signal to the front-stage boost chip to dynamically limit the power, the operating point of the Wanxiang Ocean Current Power Generation Device is changed, so that the Wanxiang Ocean Current Power Generation Device always operates at the maximum power output point under the current ocean current conditions.

9. The underwater flash charging method based on omnidirectional ocean current energy harvesting according to claim 7, characterized in that, The process of inserting a reverse discharge pulse is as follows: During the high-current constant-current charging phase, after every T seconds of high-current charging, the output is stopped for t1 milliseconds and left to stand still. Then, the phase angle polarity of the dual active bridge bidirectional DC-DC converter is changed, and it operates in reverse for t2 milliseconds to extract discharge pulses from the battery to forcibly eliminate concentration polarization on the electrode surface. After the reverse pulse ends, forward high-current charging is immediately resumed.

10. The underwater flash charging method based on omnidirectional ocean current energy harvesting according to claim 7, characterized in that, The steps for storing electrical energy in a tiered energy storage circuit include: Real-time monitoring of the terminal voltage of the supercapacitor bank; When the terminal voltage reaches the first threshold, the supercapacitor bank will transfer energy to the deep-sea battery bank. When the terminal voltage is lower than the second threshold, the supercapacitor bank stops energy transfer and continues to store energy.

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