Crane main hook potential energy recovery system based on direct current bus coupling and maritime work crane

Abstract

The utility model relates to a crane main hook potential energy recovery system based on direct-current bus coupling and a maritime work crane, and the crane main hook potential energy recovery system comprises a hoisting crane which comprises a winch and a hoisting motor connected with the winch through a speed reducer, and the hoisting motor is connected with a direct-current bus through a first inverter; the potential energy recovery unit comprises a bidirectional DC / DC converter connected with the DC bus and an energy storage device connected with the bidirectional DC / DC converter; and the potential energy consumption unit comprises a switching device connected with the direct current bus, and the switching device is connected with a brake resistor. Energy regeneration is achieved through the two-way DC / DC converter, and the two-way DC / DC converter fully recovers electric energy generated when the lifting motor is driven by a lifting hook lowered by the lifting crane to the energy storage device. The bidirectional DC / DC converter enables the electric energy stored by the energy storage device to be used by the lifting crane or other loads through voltage transformation, so that a large amount of electricity utilization cost can be saved, the energy loss is reduced, and the economic benefit of equipment is improved.

Description

Technical Field

[0001] This application relates to the field of offshore crane technology, and in particular to a crane main hook potential energy recovery system based on DC bus coupling and an offshore crane. Background Technology

[0002] Offshore cranes are lifting equipment specifically designed for offshore operations. They are commonly used in marine engineering projects such as offshore platform construction, ship repair, and oil field development. They can perform lifting, transporting, and installation operations at sea, providing crucial support for marine engineering projects.

[0003] The lifting and raising of cargo by an offshore crane is mainly divided into three stages: the start-up stage, the steady lifting stage, and the braking stage.

[0004] Start-up phase: The hoisting motor starts running, driving the drum to lift the load. Under the tension of the wire rope, the cargo leaves the ground and accelerates upward, with the speed accelerating from 0 to v. This process can be approximated as uniformly accelerated linear motion. At this time, the electrical energy of the motor is converted into the potential energy of the cargo and hook, the kinetic energy of the cargo and hook, and the energy consumed by the transmission device (including frictional energy and rotational kinetic energy).

[0005] Stable ascent phase: The hoisting drum pulls the cargo upward at a constant speed v. The electrical energy consumed by the electric motor is converted into the potential energy of the cargo and hook, and the energy consumed by the transmission device.

[0006] Braking phase: The motor begins to decelerate, and the cargo and hook slow down under the influence of gravity, resulting in a decrease in kinetic energy and an increase in potential energy. Aside from a portion being converted into potential energy, the electrical energy of the motor and the kinetic energy of the cargo and hook are consumed by the braking and transmission devices.

[0007] When the hoisting mechanism is lowering, a free-fall method is generally used to increase the descent speed in order to improve work efficiency. When the descent speed increases to the rated speed of a single wire rope (usually 1 to 1.5 times the rated speed during hoisting), the hoisting mechanism will use an external expansion brake to apply to the hoisting drum, causing the load to decelerate to the designated position. This process is divided into: the free-fall stage, the uniform descent stage, and the braking stage.

[0008] Free fall phase: As the load begins to fall, the drum drives the motor to idle, and the load and hook fall under gravity, with the load speed increasing from 0 to v1. The gravitational potential energy of the load and hook is converted into the kinetic energy of the load and lifting device, as well as losses in the transmission mechanism.

[0009] Uniform descent phase: When the maximum descent speed v1 of the cargo is reached, the armature circuit of the motor is connected to the energy-consuming resistor, which maintains a certain braking torque on the motor, allowing the cargo to fall at a uniform speed. At this time, the gravitational potential energy of the cargo and hook is converted into the kinetic energy of the transmission device and the electrical energy consumed by the energy-consuming resistor.

[0010] Braking phase: During braking, to prevent hook slippage, when the motor is disconnected, the brake engages, and the kinetic and potential energy of the load and hook is consumed by the brake and transmission mechanism.

[0011] The gravitational potential energy of the hook and cargo is partially converted into heat energy by the energy-consuming resistor and brake, while the remaining portion is consumed by the transmission mechanism. The energy consumed by the transmission mechanism mainly takes two forms: heat loss due to friction between the surfaces of relatively moving parts; and kinetic energy loss due to the rotation of each part. The kinetic energy of the transmission mechanism is ultimately converted into heat energy due to friction between the components within the device. Therefore, when the cargo is lowered, the potential energy of the cargo and hook is ultimately entirely converted into heat energy.

[0012] In the lifting mechanism, the energy consumed by the transmission device is unavoidable, and the energy consumption can only be reduced by improving the mechanical efficiency of the transmission system. The energy consumed by the braking device can be reduced by electric braking, and the electrical energy consumed by the energy-consuming resistor can be considered for recovery.

[0013] When a traditional offshore crane lowers a heavy load using its main hook, the potential energy is dissipated as heat through the braking resistor, resulting in an energy utilization rate of less than 20%. Existing improved technologies have the following drawbacks:

[0014] 1. Inverter feedback grid solution: This requires modification of the original 24-pulse rectifier system, introduces harmonic interference, and is costly.

[0015] 2. Supercapacitor energy storage solution: limited by short capacitor cycle life, rapid capacity decay, and poor long-term stability.

[0016] 3. Direct battery connection scheme: Due to the mismatch between the DC bus voltage fluctuation (500-1000V) and the battery pack voltage (300-500V), the efficiency is low (<70%). Summary of the Invention

[0017] This application provides a crane main hook potential energy recovery system and an offshore crane based on DC bus coupling, in order to solve the problem in the related technology that when the main hook of a traditional offshore crane lowers a heavy object, the potential energy is dissipated as heat through the braking resistor, resulting in energy waste.

[0018] The first aspect of this application provides a crane main hook potential energy recovery system based on DC bus coupling, including:

[0019] The crane includes a winch and a crane motor connected to the winch via a speed reducer. The crane motor is connected to a DC bus via a first inverter.

[0020] The potential energy recovery unit includes a bidirectional DC / DC converter connected to the DC bus and an energy storage device connected to the bidirectional DC / DC converter.

[0021] The potential energy consumption unit includes a switching device connected to the DC bus, and the switching device is connected to a braking resistor.

[0022] In some embodiments, the system further includes a marine power supply connected to the DC bus, the marine power supply comprising a diesel generator set, a 24-pulse rectifier connected to the diesel generator set, and the output of the 24-pulse rectifier connected to the DC bus.

[0023] In some embodiments: the 24-pulse rectifier includes two sets of 12-pulse rectifiers, each 12-pulse rectifier including a phase-shifting transformer, a rectifier connected to the phase-shifting transformer, and an isolating switch, a fuse, and a contactor connected in series between the phase-shifting transformer and the rectifier.

[0024] In some embodiments, the potential energy recovery unit is further connected to a marine power distribution cabinet, which includes a disconnecting switch, a fuse, a contactor, and a second inverter connected in series. The input terminal of the disconnecting switch is connected to the energy storage device, and the output terminal of the second inverter is connected to marine electrical appliances.

[0025] In some embodiments, the winch is connected to a hook via a wire rope and pulley block.

[0026] In some embodiments: the output shaft of the crane motor is connected to a high-speed end brake via a coupling, and the winch is equipped with a low-speed end brake for the brake drum.

[0027] In some embodiments: the switching device is a high-power transistor connected to the DC bus, the high-power transistor is connected to a braking resistor, and the high-power transistor is used to turn on the DC bus when the voltage of the DC bus is lower than a set threshold.

[0028] In some embodiments, the winch and the lifting motor are each provided in two sets, and the two sets of lifting motors are respectively connected to the DC bus through the first inverter.

[0029] In some embodiments, the crane motor is a permanent magnet synchronous motor, and the permanent magnet synchronous motor is connected to a frequency converter.

[0030] The second aspect of this application provides an offshore crane, including: the crane main hook potential energy recovery system based on DC bus coupling as described in any of the above embodiments.

[0031] The beneficial effects of the technical solution provided in this application include:

[0032] This application provides a crane main hook potential energy recovery system based on DC bus coupling and an offshore crane. The crane main hook potential energy recovery system based on DC bus coupling includes a crane, which comprises a winch and a crane motor connected to the winch via a reducer. The crane motor is connected to a DC bus via a first inverter. The system also includes a potential energy recovery unit, comprising a bidirectional DC / DC converter connected to the DC bus and an energy storage device connected to the bidirectional DC / DC converter. Finally, it includes a potential energy consumption unit, comprising a switching device connected to the DC bus and a braking resistor connected to the switching device.

[0033] Therefore, the crane main hook potential energy recovery system based on DC bus coupling in this application has a potential energy recovery unit connected to the DC bus. This potential energy recovery unit regenerates energy through a bidirectional DC / DC converter. The bidirectional DC / DC converter fully recovers the electrical energy generated by the crane's hook-lowering drive motor into the energy storage device. The bidirectional DC / DC converter then transforms the stored electrical energy to supply the crane's lifting or other loads, saving significant electricity costs, reducing energy loss, and improving equipment economic efficiency. When the voltage of the electrical energy generated by the crane's hook-lowering drive motor is lower than the input voltage of the bidirectional DC / DC converter, the switching device connects the braking resistor to the DC bus, dissipating the electrical energy on the DC bus through the braking resistor. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments 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.

[0035] Figure 1 This is a circuit diagram of the crane main hook potential energy recovery system according to an embodiment of this application;

[0036] Figure 2 This is a schematic diagram of the structure of the crane hook connected to the embodiment of this application;

[0037] Figure 3 This is a structural schematic diagram of the crane according to an embodiment of this application.

[0038] Figure label:

[0039] 1. Crane motor; 2. First inverter; 3. DC bus; 4. Bidirectional DC / DC converter; 5. Energy storage device; 6. Switching device; 7. Braking resistor; 8. Phase-shifting transformer; 9. Disconnecting switch; 10. Fuse; 11. Contactor; 12. Rectifier; 13. Second inverter; 14. Winch; 15. Pulley block; 16. Wire rope; 17. Hook; 18. Gear reducer; 19. Coupling; 20. High-speed end brake; 21. Low-speed end brake. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] This application provides a crane main hook potential energy recovery system and an offshore crane based on DC bus coupling. It can solve the problem of energy waste in traditional offshore cranes where potential energy is dissipated as heat through braking resistors when lowering heavy objects.

[0042] See Figure 1 and Figure 3 As shown, the first aspect of this application provides a crane main hook potential energy recovery system based on DC bus coupling, including:

[0043] The crane includes a winch 14 and a crane motor 1 connected to the winch 14 via a reducer 18. The crane motor 1 is connected to a DC bus 3 via a first inverter 2. The DC bus 3 provides DC power to the first inverter 2, which inverts the DC power from the DC bus 3 into AC power to power the crane motor 1.

[0044] The lifting motor 1 drives the winch 14 to wind or unwind the wire rope 16, thereby lifting and releasing the hook 17. The winch 14 lowers the hook 17 and the load, releasing gravitational potential energy, which drives the lifting motor 1 to generate electrical energy. This electrical energy is rectified into DC power by the first inverter and then transmitted to the DC bus 3.

[0045] The potential energy recovery unit includes a bidirectional DC / DC converter 4 connected to the DC bus 3, and an energy storage device 5 connected to the bidirectional DC / DC converter 4. The bidirectional DC / DC converter 4 transforms the DC power on the DC bus 3 (the output voltage of the bidirectional DC / DC converter 4 is matched with the rated voltage of the energy storage device 5) and then transmits it to the energy storage device 5 for storage. The electrical energy stored in the energy storage device 5 is transformed back to DC power by the bidirectional DC / DC converter 4 and then input back to the DC bus 3 to provide power to the crane motor 1.

[0046] The potential energy dissipation unit includes a switching device 6 connected to the DC bus 3, and a braking resistor 7 connected to the switching device 6. When the voltage of the DC power transmitted to the DC bus 3 by the electrical energy generated by the hoisting motor 1 lowering the load is less than the rated input voltage of the bidirectional DC / DC converter 4, the switching device 6 connects the braking resistor 7 to the DC bus 3, thereby dissipating the electrical energy generated by the hoisting motor 1 lowering the load by generating heat through the braking resistor 7.

[0047] The crane main hook potential energy recovery system based on DC bus coupling in this embodiment of the application has a potential energy recovery unit connected to the DC bus 3. The potential energy recovery unit realizes energy regeneration through a bidirectional DC / DC converter 4. The bidirectional DC / DC converter 4 fully recovers the electrical energy generated by the crane lowering hook 17 driving the crane motor 1 to the energy storage device 5. The bidirectional DC / DC converter 4 then transforms the electrical energy stored in the energy storage device 5 to supply the crane lifting or other loads.

[0048] This application can save a significant amount of electricity costs, reduce energy consumption, and improve the economic efficiency of equipment. When the voltage of the electrical energy generated by the crane motor 1 driving the lowering hook 17 of the crane is lower than the input voltage of the bidirectional DC / DC converter 4, the switching device 6 connects the braking resistor 7 to the DC bus 3, and consumes the electrical energy on the DC bus 3 through the braking resistor 7.

[0049] In some alternative embodiments: see Figure 1 As shown, the first aspect of this application provides a crane main hook potential energy recovery system based on DC bus coupling. The crane main hook potential energy recovery system also includes a marine power supply connected to the DC bus 3. The marine power supply includes a diesel generator set (not shown in the figure), a 24-pulse rectifier connected to the diesel generator set, and the output terminal of the 24-pulse rectifier connected to the DC bus 3.

[0050] The 24-pulse rectifier comprises two sets of 12-pulse rectifiers operating in parallel. Each 12-pulse rectifier includes a phase-shifting transformer 8 and a rectifier 12 connected to the phase-shifting transformer 8. A disconnecting switch 9, a fuse 10, and a contactor 11 are connected in series between the phase-shifting transformer 8 and the rectifier 12. The 24-pulse rectifier uses a phase delay circuit to split the input AC signal into 12 AC signals with a 30-degree phase difference. These signals are then rectified and filtered to obtain a smooth DC output signal.

[0051] In some alternative embodiments: see Figure 1 As shown, the first aspect of this application provides a crane main hook potential energy recovery system based on DC bus coupling. The potential energy recovery unit of the crane main hook potential energy recovery system is also connected to a marine power distribution cabinet. The marine power distribution cabinet includes a disconnecting switch 9, a fuse 10, a contactor 11, and a second inverter 13 connected in series. The input terminal of the disconnecting switch 9 is connected to the energy storage device 5, and the output terminal of the second inverter 13 is connected to the marine electrical appliances.

[0052] The marine power distribution cabinet is used to control and invert the electrical energy stored in the energy storage unit 5 in the potential energy recovery unit. The electrical energy stored in the energy storage unit 5 is inverted into three-phase AC power and then connected to the ship's power grid to supply power to the ship's electrical appliances, thereby reducing the energy consumption of the diesel generator set.

[0053] In some alternative embodiments: see Figure 2 and Figure 3 As shown, the first aspect of this application provides a crane main hook potential energy recovery system based on DC bus coupling. The hoist 14 of the crane main hook potential energy recovery system is connected to a hook 17 via a wire rope 16 and a pulley block 15. Both the hoist 14 and the lifting motor 1 are provided in two sets, and the two sets of lifting motors 1 are respectively connected to the DC bus 3 via a first inverter 2.

[0054] The output shaft of the lifting motor 1 is connected to a high-speed end brake 20 via a coupling 19, and the winch 14 is equipped with a low-speed end brake 21 for braking the drum. The lifting motor 1 is preferably a permanent magnet synchronous motor, which is connected to a frequency converter. The frequency converter regulates the frequency at which the DC bus 3 supplies power to the permanent magnet synchronous motor, thereby adjusting the power and speed of the motor. The low-speed end brake 21 and the high-speed end brake 20 are used to control the speed of the winch 14 and the lifting motor 1, so that the hook 17 can lift goods at a set lifting and lowering speed.

[0055] In some alternative embodiments: see Figure 2 and Figure 3As shown, the first aspect of this application provides a crane main hook potential energy recovery system based on DC bus coupling. The switching device 6 of this crane main hook potential energy recovery system is a high-power transistor connected to the DC bus 3. The high-power transistor is connected to a braking resistor 7. The high-power transistor is used to connect the braking resistor 7 to the DC bus 3 when the voltage of the DC bus 3 is lower than a set threshold. For example, when the voltage of the DC bus 3 is less than 780V, the high-power transistor connects the braking resistor 7 to the DC bus 3 to dissipate energy.

[0056] The second aspect of this application provides an offshore crane, including: the crane main hook potential energy recovery system based on DC bus coupling as described in any of the above embodiments.

[0057] Working principle

[0058] This application provides a crane main hook potential energy recovery system and an offshore crane based on DC bus coupling. Since the crane main hook potential energy recovery system based on DC bus coupling of this application is equipped with a crane, the crane includes a winch 14 and a crane motor 1 connected to the winch 14 through a reducer 18. The crane motor 1 is connected to a DC bus 3 through a first inverter 2; a potential energy recovery unit, which includes a bidirectional DC / DC converter 4 connected to the DC bus 3 and an energy storage device 5 connected to the bidirectional DC / DC converter 4; and a potential energy consumption unit, which includes a switching device 6 connected to the DC bus 3 and a braking resistor 7 connected to the switching device 6.

[0059] Therefore, the crane main hook potential energy recovery system based on DC bus coupling in this application has a potential energy recovery unit connected to the DC bus 3. This potential energy recovery unit achieves energy regeneration through a bidirectional DC / DC converter 4. The bidirectional DC / DC converter 4 fully recovers the electrical energy generated by the crane lowering hook 17 driving the crane motor 1 to the energy storage device 5. The bidirectional DC / DC converter 4 then transforms the electrical energy stored in the energy storage device 5 to supply the crane lifting or other loads, which can save a lot of electricity costs, reduce energy loss, and improve the economic efficiency of the equipment. When the voltage of the electrical energy generated by the crane lowering hook 17 driving the crane motor 1 is lower than the input voltage of the bidirectional DC / DC converter 4, the switching device 6 connects the braking resistor 7 to the DC bus 3, and the electrical energy on the DC bus 3 is consumed through the braking resistor 7.

[0060] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0061] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0062] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. 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 this application. Therefore, this application 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 claimed herein.

Claims

1. A crane main hook potential energy recovery system based on DC bus coupling, characterized in that, include: The crane includes a winch (14) and a crane motor (1) connected to the winch (14) via a reducer (18). The crane motor (1) is connected to a DC bus (3) via a first inverter (2). The potential energy recovery unit includes a bidirectional DC / DC converter (4) connected to the DC bus (3) and an energy storage device (5) connected to the bidirectional DC / DC converter (4). The potential energy consumption unit includes a switching device (6) connected to the DC bus (3), and the switching device (6) is connected to a braking resistor (7).

2. The crane main hook potential energy recovery system based on DC bus coupling as described in claim 1, characterized in that: It also includes a marine power supply connected to the DC bus (3), the marine power supply including a diesel generator set, a 24-pulse rectifier connected to the diesel generator set, and the output end of the 24-pulse rectifier connected to the DC bus (3).

3. The crane main hook potential energy recovery system based on DC bus coupling as described in claim 2, characterized in that: The 24-pulse rectifier includes two sets of 12-pulse rectifiers. Each 12-pulse rectifier includes a phase-shifting transformer (8) and a rectifier (12) connected to the phase-shifting transformer (8). A disconnecting switch (9), a fuse (10), and a contactor (11) are connected in series between the phase-shifting transformer (8) and the rectifier (12).

4. The crane main hook potential energy recovery system based on DC bus coupling as described in claim 1, characterized in that: The potential energy recovery unit is also connected to a marine power distribution cabinet, which includes a disconnect switch (9), a fuse (10), a contactor (11), and a second inverter (13) connected in series. The input terminal of the disconnect switch (9) is connected to the energy storage device (5), and the output terminal of the second inverter (13) is connected to the marine electrical appliances.

5. The crane main hook potential energy recovery system based on DC bus coupling as described in claim 1, characterized in that: The winch (14) is connected to a hook (17) via a wire rope (16) and a pulley block (15).

6. The crane main hook potential energy recovery system based on DC bus coupling as described in claim 1, characterized in that: The output shaft of the crane motor (1) is connected to a high-speed end brake (20) via a coupling (19), and the winch (14) is equipped with a low-speed end brake (21) for the brake drum.

7. The crane main hook potential energy recovery system based on DC bus coupling as described in claim 1, characterized in that: The switching device (6) is a high-power transistor connected to the DC bus (3). The high-power transistor is connected to the braking resistor (7). The high-power transistor is used to turn on the DC bus (3) when the voltage of the DC bus (3) is lower than a set threshold.

8. The crane main hook potential energy recovery system based on DC bus coupling as described in claim 1, characterized in that: The winch (14) and the crane motor (1) are each provided in two sets, and the two sets of crane motors (1) are respectively connected to the DC bus (3) through the first inverter (2).

9. The crane main hook potential energy recovery system based on DC bus coupling as described in claim 1 or 8, characterized in that: The crane motor (1) is a permanent magnet synchronous motor, and the permanent magnet synchronous motor is connected to a frequency converter.

10. A marine crane, characterized in that, include: The crane main hook potential energy recovery system based on DC bus coupling as described in any one of claims 1 to 9.

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