Underwater vehicle charging system and charging method

Abstract

The present invention provides an underwater vehicle charging system, or charging method, that addresses the problem of existing underwater vehicle wireless charging systems requiring a heavy coupler on the vehicle end, which affects the underwater vehicle's load capacity, operating time, and operational flexibility. The present invention utilizes a permanent magnet synchronous motor, which the underwater vehicle must carry, for energy replenishment. The electromotive force generated by the permanent magnet synchronous motor's reversal directly charges the underwater vehicle's battery, avoiding the added load of a coupler installed on the vehicle end required for conventional wireless charging. The charging system includes a charging device disposed underwater and a one-way clutch disposed between the underwater vehicle's permanent magnet synchronous motor drive shaft and the propeller. The charging device includes a base platform, a mobile platform, a motor, a charging rod, a fixed electromagnet, a communication unit, and a control unit. The motor converts the electrical energy obtained by the charging device into mechanical energy, which is transferred to the permanent magnet synchronous motor drive shaft via the charging rod, driving the drive shaft to reverse.

Description

Technical Field

[0001] The present invention belongs to the technical field of underwater charging, and in particular relates to a charging system and a charging method for an underwater vehicle. Background Art

[0002] Autonomous underwater vehicles (AUVs), a vital maritime force, are crucial tools for marine geological and geomorphological exploration, marine environmental observation, and marine resource exploration. However, their size and payload limitations, coupled with the limited battery capacity, have hindered their further development. Because salvaging, recovery, and recharging require human intervention, researchers are actively exploring methods for energy recharge without salvaging or recovery.

[0003] Currently, wireless charging technology is widely used for recharging underwater vehicles, as it avoids the potential leakage risks associated with wet plugging and unplugging underwater and offers a certain degree of transmission efficiency. This is reflected in Chinese patent applications CN202311226168.X and CN202311155076.7. However, wireless charging systems require a heavy coupler on the underwater vehicle, significantly impacting the vehicle's load capacity, operating time, and flexibility.

[0004] To this end, the present invention provides an underwater vehicle charging device that does not require a heavy coupler to be carried on the vehicle end, thereby reducing the impact of the charging system on the operating capability of the underwater vehicle. Summary of the Invention

[0005] The present invention aims to provide an underwater vehicle charging system and method to address the shortcomings of existing underwater vehicle wireless charging systems, which require a heavy coupler to be installed on the vehicle end, affecting the underwater vehicle's load capacity, operation time and operation flexibility.

[0006] The concept of the present invention:

[0007] In response to the problem that current wireless charging systems require a coupler on the underwater vehicle side, the present invention considers how to solve the problem of charging the underwater vehicle itself without increasing or minimizing the load on the underwater vehicle. To this end, further research was conducted on the structure of the underwater vehicle, and it was found that the permanent magnet synchronous motor (located at the tail of the underwater vehicle and serving as the propulsion motor of the underwater vehicle) that the underwater vehicle itself must carry is capable of serving as an energy supply device on the vehicle side. The difference between its forward and reverse rotation can be utilized to enable it to have both driving and charging functions. However, in complex underwater operating environments, if the functions of the permanent magnet synchronous motor are to be fully utilized, it is also necessary to consider the impact of water flow on the system and the problem of the propeller on its output shaft rotating with it during reverse rotation. Therefore, its structure needs to be optimized to enable it to achieve the goal of energy replenishment with low loss without increasing or minimizing the load on the underwater vehicle itself.

[0008] To achieve the above objectives, the technical solutions provided by the present invention are:

[0009] A charging system for an underwater vehicle is unique in that it generates an induced voltage by driving the drive shaft of the underwater vehicle's permanent magnet synchronous motor in reverse direction (reversal here refers to the direction opposite to the direction of rotation of the drive shaft of the permanent magnet synchronous motor when the underwater vehicle is sailing, that is, the direction of rotation of the drive shaft of the permanent magnet synchronous motor when the underwater vehicle is sailing is defined as forward), and the underwater vehicle's electrical system stores and transforms the induced voltage, storing it in the underwater vehicle's battery to achieve charging purposes. The underwater vehicle's electrical system has the functions of controlling both the operation of the permanent magnet synchronous motor and the charging of the underwater vehicle's battery.

[0010] The propulsion system of a conventional underwater vehicle only needs to work in the propulsion mode, that is, through the battery → controller → propeller (permanent magnet synchronous motor). At this time, the electrical system only needs to be responsible for controlling the motor. However, in the present invention, because the propulsion system needs to have both propulsion mode and charging mode, that is, battery → controller → propeller and battery ← controller ← propeller, the electrical system at this time needs to have both the functions of controlling the permanent magnet synchronous motor and controlling battery charging. Therefore, while designing the charging system, the present invention also needs to modify the electrical system in the conventional underwater vehicle so that it has the function of controlling battery charging, and can switch between the two functions of controlling the motor and controlling battery charging as needed, and has the ability to monitor the battery current and voltage, and can determine whether the battery is full through the current and voltage information. This part of the modification is relatively easy to implement for those skilled in the art. It is enough to optimize the controller into a battery charging and propulsion motor controller;

[0011] The charging system includes a charging device arranged underwater, and a one-way clutch arranged between the drive shaft of the permanent magnet synchronous motor of the underwater vehicle and the propeller;

[0012] The charging device includes a base platform, a mobile platform, a motor, a charging rod, a fixed electromagnet, a communication unit and a control unit;

[0013] The base platform is provided with a watertight connector, which is connected to an external power supply via a watertight cable;

[0014] The motor is mounted on the base platform via a mobile platform, and its output shaft is coaxially connected to one end of the charging rod;

[0015] The end surface structure of the other end of the charging rod is adapted to the end surface structure of the transmission shaft of the permanent magnet synchronous motor of the underwater vehicle;

[0016] The fixed electromagnet is arranged in the base platform, and a vehicle fixing area is formed on the upper surface of the base platform;

[0017] The communication unit is arranged in the base platform, communicates with the underwater vehicle and the control unit, and determines whether the underwater vehicle has reached the vehicle fixing area;

[0018] The control unit is provided in the base platform and is used to control the on and off of the fixed electromagnet, the start and stop of the motor, and the position of the mobile platform on the base platform (i.e., the position of the mobile platform relative to the base platform, thereby aligning and connecting the motor output shaft, the charging rod, and the permanent magnet synchronous motor drive shaft of the underwater vehicle installed on the mobile platform);

[0019] During charging, the motor output shaft, the charging rod and the underwater vehicle's permanent magnet synchronous motor drive shaft are coaxial; due to the introduction of a one-way clutch, when the underwater vehicle's permanent magnet synchronous motor drive shaft reverses, the propeller will automatically disengage from the drive shaft, so the propeller will not follow the drive shaft in reverse rotation. In this way, it will not drive the surrounding water flow, and will not generate any power transmission function, thus avoiding unnecessary losses.

[0020] Furthermore, the docking area between the underwater vehicle's permanent magnet synchronous motor drive shaft and the charging rod on the base platform is a semi-enclosed structure. After the underwater vehicle docks with the charging device, the propeller is located within this semi-enclosed structure. This avoids the greater viscous drag caused by the drive shaft rotating in reverse in an open water environment during charging, thereby improving the system's charging efficiency to a certain extent. Generally speaking, charging efficiency = output charging power / total input power, where total input power = output charging power + power loss. Because the aforementioned design avoids the greater viscous drag caused by the drive shaft rotating in reverse in an open water environment during charging, it reduces the losses caused by this part, thereby improving the system's charging efficiency.

[0021] Furthermore, one end of the charging rod is adaptively connected to the motor output shaft through a flat key, and the other end is adaptively connected to the drive shaft of the underwater vehicle permanent magnet synchronous motor through a spline.

[0022] At the same time, the present invention also provides a method for charging an underwater vehicle using the above underwater vehicle charging system, which is special in that it includes the following steps:

[0023] S1. When the underwater vehicle detects that the battery is low, it communicates with the charging device through the communication unit to determine the location of the charging device and gradually approaches the charging device;

[0024] S2. The charging device detects that the underwater vehicle has reached the vehicle fixing area, and the control unit activates the fixing electromagnet to fix the underwater vehicle to the base platform of the charging device;

[0025] The communication unit communicates with the underwater vehicle to determine whether the underwater vehicle has reached an area where it can be recharged and replenished with energy, providing the control unit with a judgment condition for whether to activate the fixed electromagnet. When the communication unit communicates with the underwater vehicle and determines that the current location is a location where it can be recharged and replenished with energy, the control unit receives the instruction and controls the fixed electromagnet to attract the underwater vehicle, preparing for the next step of charging.

[0026] S3. The charging device control unit controls the movement of the mobile platform to ensure that the charging rod is adapted to the drive shaft of the underwater vehicle's permanent magnet synchronous motor;

[0027] S4. The charging device control unit starts the motor, which drives the drive shaft of the underwater vehicle's permanent magnet synchronous motor to rotate in the opposite direction, driving the permanent magnet synchronous motor rotor to cut the stator to generate a magnetic field, thereby inducing an induced voltage on the stator;

[0028] S5. The internal electrical system of the underwater vehicle stores and transforms the induced voltage generated by S4, and stores it in the battery of the underwater vehicle to complete charging.

[0029] Furthermore, the charging rod is connected to the transmission shaft of the permanent magnet synchronous motor of the underwater vehicle through a spline adapter.

[0030] Working principle of the present invention:

[0031] When the underwater vehicle detects a low battery, it communicates with the charging device, determines its location, and gradually approaches it. When the charging device detects that the underwater vehicle has reached the designated location, the control unit activates the fixed electromagnet to secure the underwater vehicle to the base platform of the charging device. The charging device control unit controls the movement of the mobile platform to ensure that the spline of the charging rod is connected to the spline set at the end of the underwater vehicle's drive shaft. After confirming the connection, the control unit starts the motor, which drives the drive shaft to rotate in the opposite direction. Due to the one-way clutch between the drive shaft and the propeller, the propeller automatically disengages from the drive shaft during the reversal process to reduce losses. At this time, the charging device's motor drives the permanent magnet synchronous motor rotor through the drive shaft to cut the stator to generate a magnetic field, thereby inducing an induced voltage on the stator. The underwater vehicle's internal electrical system stores and transforms the induced voltage, storing it in the vehicle's battery, completing the charging process.

[0032] Compared with conventional underwater energy supply devices, the present invention has the following advantages:

[0033] 1. The present invention boasts a simple structure and cleverly utilizes the permanent magnet synchronous motor (PMSM), which is a must-have for underwater vehicles, for energy replenishment. The induced voltage generated by the PMSM's reverse rotation directly charges the underwater vehicle's battery, eliminating the need for conventional wireless charging to install a coupler on the vehicle, which increases the load. This significantly improves the underwater vehicle's load capacity, operating time, and operational flexibility. Because the underwater vehicle's propeller is mounted on the PMSM's drive shaft, it must generate sufficient thrust to maintain the vehicle's speed during forward rotation. During reverse charging, the propeller remains stationary to avoid excessive charging losses. Therefore, a one-way clutch is incorporated between the drive shaft and propeller. During reverse rotation, the propeller automatically disengages from the drive shaft, eliminating any power transmission and reducing unnecessary energy loss caused by the propeller during reverse charging.

[0034] 2. The semi-enclosed structure of the one-way clutch and the charging device at the underwater vehicle end of the present invention reduces energy loss during the replenishment process, avoids the greater viscous resistance caused by the reverse rotation of the drive shaft in an open water environment during charging, and improves charging efficiency.

[0035] 3. The present invention avoids the tedious and time-consuming process of salvaging the underwater vehicle for charging. When the autonomous underwater vehicle needs to be charged, it only needs to dock the underwater vehicle on the charging device to achieve power replenishment, effectively improving the continuity, concealment and intelligence of the autonomous underwater vehicle's operation.

[0036] 4. The charging method of the present invention effectively avoids the weight of the magnetic coupler required to be carried in the magnetic coupling resonant underwater wireless charging system, while avoiding the electromagnetic radiation generated by the magnetic coupler, thereby improving the safety and stability of the vehicle operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the overall structure of the underwater vehicle charging device of the present invention;

[0038] Figure 2 Schematic diagram of the underwater vehicle end structure of the present invention; wherein (a) is the end face structure of the underwater vehicle, and (b) is the AA cross-sectional view in (a);

[0039] Figure 3 This is a flow chart of underwater docking and charging of the underwater vehicle charging device of the present invention.

[0040] The reference numerals are as follows:

[0041] 1- underwater vehicle, 2- permanent magnet synchronous motor, 21- permanent magnet synchronous motor stator, 22- permanent magnet synchronous motor rotor, 3- transmission shaft, 4- propeller, 5- one-way clutch, 6- spline, 7- charging device, 8- base platform, 9- mobile platform, 10- motor, 11- fixed electromagnet, 12- communication unit, 13- control unit, 14- watertight connector, 15- battery, 16- battery charging and propulsion motor controller, 17- charging rod, 18- semi-enclosed structure. DETAILED DESCRIPTION

[0042] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments:

[0043] like Figure 1 and Figure 2 The underwater vehicle charging system shown here generates an induced voltage by driving the drive shaft 3 of the permanent magnet synchronous motor 2 of the underwater vehicle 1 to reverse (the permanent magnet synchronous motor 2 includes a permanent magnet synchronous motor stator 21 and a permanent magnet synchronous motor rotor 22. The rotation direction of the drive shaft 3 of the permanent magnet synchronous motor 2 when the underwater vehicle 1 is sailing is defined as the forward direction). The internal electrical system of the underwater vehicle 1 (i.e., the battery charging and propulsion motor controller 16 between the permanent magnet synchronous motor 2 and the battery 15 is connected, which has the functions of controlling the operation of the permanent magnet synchronous motor 2 and controlling the charging of the battery 15 of the underwater vehicle 1) stores and transforms the induced voltage and stores it in the battery 15 of the underwater vehicle 1 to achieve the charging purpose.

[0044] The charging system includes a charging device 7 disposed underwater, and a one-way clutch 5 disposed between the drive shaft 3 of the permanent magnet synchronous motor 2 and the propeller 4 of the underwater vehicle 1. The charging device 7 includes a base platform 8, a mobile platform 9, a motor 10, a charging rod 17, a fixed electromagnet 11, a communication unit 12, and a control unit 13.

[0045] A watertight connector 14 is provided on the side of the base platform 8, which is connected to an external power supply through a watertight cable. The power supply can be a mother ship on the water or a power supply device on the shore.

[0046] The motor 10 is installed on the base platform 8 through the mobile platform 9, and its output shaft is coaxially connected to one end of the charging rod 17 through a flat key (that is, the end face of the output shaft of the motor 10 and the end face of one end of the charging rod 17 are both provided with flat keys, which are matched with each other through the flat keys); the other end of the charging rod 17 is connected to the drive shaft 3 of the permanent magnet synchronous motor 2 of the underwater vehicle 1 through a spline 6 (that is, the end face of the other end of the charging rod 17 and the end face of the drive shaft 3 are both provided with splines 6, which are matched with each other through the spline 6); the motor 10 converts the electrical energy obtained by the charging device 7 into mechanical energy, and effectively transmits it to the drive shaft 3 of the permanent magnet synchronous motor 2 through the charging rod 17, driving the drive shaft 3 to reverse.

[0047] The fixed electromagnet 11 is provided in the base platform 8, and a vehicle fixing area is formed on the upper surface of the base platform 8 so as to securely connect the underwater vehicle 1 to the charging device 7, thereby ensuring that the underwater vehicle 1 does not shake with the water flow during the charging process and ensuring stability;

[0048] The communication unit 12 is provided in the base platform 8 and communicates with the underwater vehicle 1 and the control unit 13 to determine whether the underwater vehicle 1 has reached the vehicle fixed area. During operation, the communication unit 12 needs to operate under the control of the control unit 13, and information is transmitted between the two.

[0049] The control unit 13 is provided in the base platform 8 and is used to control the on and off of the fixed electromagnet 11, the start and stop of the motor 10, and the position of the mobile platform 9 on the base platform 8;

[0050] During charging, the output shaft of the motor 10, the charging rod 17 and the drive shaft 3 of the permanent magnet synchronous motor 2 of the underwater vehicle 1 are coaxial; due to the introduction of the one-way clutch 5, when the drive shaft 3 of the permanent magnet synchronous motor 2 of the underwater vehicle 1 is reversed, the propeller 4 will automatically disengage from the drive shaft 3, so the propeller 4 will not follow the reverse rotation of the drive shaft 3, so it will not drive the surrounding water flow, and will not produce any power transmission function, thereby reducing unnecessary energy loss caused by the propeller 4 during reverse charging.

[0051] On the base platform 8, the docking area between the permanent magnet synchronous motor 2 drive shaft 3 of the underwater vehicle 1 and the charging rod 17 is designed as a semi-enclosed structure 18. In this way, after the underwater vehicle 1 is docked with the charging device 7, the propeller 4 is located in the semi-enclosed structure 18; this can avoid the greater viscous resistance caused by the reverse rotation of the drive shaft 3 in the open water environment during charging, thereby improving the system charging efficiency to a certain extent.

[0052] At the same time, the present invention provides a method for charging an underwater vehicle using the above underwater vehicle charging system. The underwater docking charging process is as follows: Figure 3 As shown, the following steps are included:

[0053] S1. When the underwater vehicle detects that the battery is low, it communicates with the charging device through the communication unit to determine the location of the charging device and gradually approaches the charging device;

[0054] S2. The charging device detects that the underwater vehicle has reached the vehicle fixing area, and the control unit activates the fixing electromagnet to fix the underwater vehicle to the base platform of the charging device;

[0055] S3. The charging device control unit controls the movement of the mobile platform to ensure that the charging rod is adapted to the drive shaft of the underwater vehicle's permanent magnet synchronous motor;

[0056] S4. The charging device control unit starts the motor, which drives the drive shaft of the underwater vehicle's permanent magnet synchronous motor to rotate in the opposite direction, driving the permanent magnet synchronous motor rotor to cut the stator to generate a magnetic field, thereby inducing an induced voltage on the stator;

[0057] S5. The internal electrical system of the underwater vehicle stores and transforms the induced voltage generated by S4, and stores it in the battery of the underwater vehicle to complete charging.

[0058] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present invention, and these modifications or replacements should all be included in the scope of protection of the present invention.

Claims

1. An underwater vehicle charging system, characterized by: The underwater vehicle permanent magnet synchronous motor (2) is driven to reversely drive a transmission shaft (3) to induce an induced voltage, and the underwater vehicle's electrical system stores and transforms the induced voltage and stores it in the underwater vehicle's battery (15) to achieve the purpose of charging. The underwater vehicle's electrical system has the functions of controlling the operation of the permanent magnet synchronous motor (2) and controlling the charging of the underwater vehicle's battery (15). The charging system comprises a charging device (7) arranged underwater, and a one-way clutch (5) arranged between a drive shaft (3) of a permanent magnet synchronous motor (2) of an underwater vehicle and a propeller (4); The charging device (7) comprises a base platform (8), a mobile platform (9), a motor (10), a charging rod (17), a fixed electromagnet (11), a communication unit (12) and a control unit (13); The base platform (8) is provided with a watertight connector (14) which is connected to an external power supply via a watertight cable; The motor (10) is mounted on the base platform (8) via the mobile platform (9), and its output shaft is coaxially connected to one end of the charging rod (17); The end surface structure of the other end of the charging rod (17) is adapted to the end surface structure of the transmission shaft (3) of the underwater vehicle permanent magnet synchronous motor (2); The fixed electromagnet (11) is arranged in the base platform (8), forming a vehicle fixing area on the upper surface of the base platform (8); The communication unit (12) is arranged in the base platform (8) and communicates with the underwater vehicle and the control unit (13) to determine whether the underwater vehicle has reached the vehicle fixing area; The control unit (13) is arranged in the base platform (8) and is used to control the on and off of the fixed electromagnet (11), the start and stop of the motor (10), and the position of the mobile platform (9) on the base platform (8); During charging, the output shaft of the motor (10), the charging rod (17) and the transmission shaft (3) of the underwater vehicle permanent magnet synchronous motor (2) are coaxial.

2. The underwater vehicle charging system according to claim 1, characterized in that: On the base platform (8), the docking area between the underwater vehicle permanent magnet synchronous motor (2) drive shaft (3) and the charging rod (17) is a semi-enclosed structure (18); After the underwater vehicle is docked with the charging device (7), the propeller (4) is located in the semi-enclosed structure (18).

3. The underwater vehicle charging system according to claim 1 or 2, characterized in that: One end of the charging rod (17) is adaptively connected to the output shaft of the motor (10) via a flat key, and the other end is adaptively connected to the transmission shaft (3) of the underwater vehicle permanent magnet synchronous motor (2) via a spline (6).

4. A method for charging an underwater vehicle using the underwater vehicle charging system according to claim 1, characterized in that: The following steps are involved: S1. When the underwater vehicle detects that the battery is low, it communicates with the charging device through the communication unit to determine the location of the charging device and gradually approaches the charging device; S2. The charging device detects that the underwater vehicle has reached the vehicle fixing area, and the control unit activates the fixing electromagnet to fix the underwater vehicle to the base platform of the charging device; S3. The charging device control unit controls the movement of the mobile platform to ensure that the charging rod is coaxially connected to the drive shaft of the underwater vehicle's permanent magnet synchronous motor; S4. The charging device control unit starts the motor, which drives the drive shaft of the underwater vehicle's permanent magnet synchronous motor to rotate in the opposite direction, driving the permanent magnet synchronous motor rotor to cut the stator to generate a magnetic field, thereby inducing an induced voltage on the stator; S5. The electrical system of the underwater vehicle stores and transforms the induced voltage generated by S4, and stores it in the battery of the underwater vehicle to complete charging.

5. The method for charging an underwater vehicle by the underwater vehicle charging system according to claim 4, characterized in that: In S3, the charging rod and the drive shaft of the underwater vehicle's permanent magnet synchronous motor are connected via a spline adapter.

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