Large crane ship energy-saving system and control method thereof

Abstract

The invention provides a large crane ship energy-saving system and a control method thereof. The large crane ship energy-saving system comprises a comprehensive energy-saving control cabinet, an energy storage system, a photovoltaic system and multiple energy-saving systems. The comprehensive energy-saving control cabinet comprises a plurality of DCDC modules, and the comprehensive energy-saving cabinet is provided with an energy management system; the energy storage system is controlled by an energy management system, and the energy storage system is electrically connected to the direct current bus through the DCDC module; the photovoltaic system is electrically connected with the energy management system and is electrically connected with the direct current bus through the DCDC module; and the plurality of energy-saving systems are electrically connected with the direct current bus through the DCDC module. The photovoltaic system and various energy-saving systems are matched with power management and distribution through different working conditions, and the technical problem that in the prior art, a large crane ship for reducing energy consumption and achieving an energy-saving and emission-reducing power system is lacked is solved.

Description

Technical Field:

[0001] The present invention relates to the technical field of engineering ships, and in particular to an energy-saving system for a large crane ship and a control method thereof. Background Art:

[0002] In recent years, the International Maritime Organization (IMO) has continuously increased its ambition for energy conservation and emission reduction, and proposed that by 2030, zero / near-zero emission technologies should account for at least 5% and strive for 10% of the total energy consumption in international shipping. Regions and industries are actively promoting the international shipping greenhouse gas emission reduction strategy. Due to the high cost of large engineering ships, users emphasize the practicability and reliability of their construction operations, regarding functionality as more important than economy. Therefore, they have not been active in the application of energy conservation and emission reduction technologies in the past. The operating characteristics of large crane ships determine that their mooring standby time accounts for a large proportion. There is no shore power condition during anchorage waiting, resulting in the need for the mooring unit to operate continuously. The low load in the living condition is not conducive to the overall energy efficiency; there is potential energy conversion during the hoisting operation of large crane ships. For example, collecting the energy during the lowering process of heavy objects will also increase the overall energy consumption of the whole ship.

[0003] There is an urgent need for an energy-saving system for large crane ships, which helps to solve the technical problem in the prior art of lacking a technology for large crane ships to reduce energy consumption and achieve energy-saving and emission-reducing power systems. Summary of the Invention:

[0004] In one embodiment, the present invention provides an energy-saving system for a large crane ship. Through the cooperation of a photovoltaic system and various energy-saving systems under different working conditions for power management and distribution, it helps to solve the technical problem in the prior art of lacking a technology for large crane ships to reduce energy consumption and achieve energy-saving and emission-reducing power systems.

[0005] The energy-saving system for the large crane ship includes an integrated energy-saving control cabinet and an energy storage system, as well as a photovoltaic system and various energy-saving systems;

[0006] The integrated energy-saving control cabinet includes a plurality of DCDC modules. The DC bus is electrically connected to the external electrical equipment through the DCDC modules, and the integrated energy-saving cabinet has an energy management system;

[0007] The energy storage system is controlled by the energy management system, and the energy storage system is electrically connected to the DC bus through the DCDC modules;

[0008] The photovoltaic system is electrically connected to the energy management system and is electrically connected to the DC bus through the DCDC modules;

[0009] A plurality of the energy-saving systems are electrically connected to the DC bus through the DCDC modules.

[0010] In one embodiment, a plurality of the energy-saving systems include a wind power generation system and a tidal current energy system.

[0011] In one embodiment, the energy-saving system of the large lifting vessel further includes an AC power distribution system, which is electrically connected to the DCAC module through an isolation transformer and then to the DC bus.

[0012] In one embodiment, the energy-saving system of the large lifting vessel includes a monitoring and protection system;

[0013] In one embodiment, the energy-saving system of the large lifting vessel includes an energy management system; the monitoring and protection system is communicatively connected to the energy management system through MODBUS RTU.

[0014] The energy management system is electrically connected to the power station management system.

[0015] In one embodiment, the energy storage system includes a domain management unit, a control room display panel, a centralized control room HMI, a high-voltage control box, an energy storage unit cluster, and a high-voltage busbar box;

[0016] The control room display panel is electrically connected to the domain management unit;

[0017] The centralized control room HMI is electrically connected to the domain management unit;

[0018] The high-voltage control box is electrically connected to the domain management unit;

[0019] The energy storage unit cluster is electrically connected to the high-voltage control box;

[0020] The high-voltage busbar box is electrically connected to the high-voltage control box, and the high-voltage busbar box is electrically connected to the DC bus through the DCDC module;

[0021] The domain management unit is electrically connected to the energy management system.

[0022] In one embodiment, the photovoltaic system includes a photovoltaic busbar box, photovoltaic modules and brackets, and a photovoltaic inverter integrated machine.

[0023] In one embodiment, the domain management unit communicates with the high-voltage control box, the high-voltage control box and the energy storage unit cluster, and the domain management unit communicates with the energy management system, and the energy management system communicates with the photovoltaic inverter integrated machine through the CAN method;

[0024] The monitoring and protection system communicates with the energy management system through the MODBUS RTU method;

[0025] The control room display panel and the centralized control room HMI communicate with the domain management box through the Ethernet method respectively, and the power station management system communicates with the energy management system through the Ethernet method.

[0026] In one embodiment, the energy storage unit cluster includes multiple clusters of energy storage units. Each energy storage unit includes a single-pack battery or capacitor. The single-pack batteries or capacitors are connected in series to form a cluster, and the energy storage units are connected in parallel.

[0027] In one embodiment, the present invention further provides a control method for an energy-saving system of a large lifting ship. Based on the above-mentioned energy-saving system of the large lifting ship, the control method includes:

[0028] Select different working modes according to different working conditions. The working modes include an energy-saving mode, a green charging mode, and a neutral mode;

[0029] When the energy-saving mode is selected, the DCAC module starts up and is connected to the AC system in parallel. The energy storage system starts up, and the photovoltaic system can start up / stop, and the AC generator set can start up / stop;

[0030] When the green charging mode is selected, the DCAC module shuts down, the energy-saving system is isolated from the AC system, the energy storage system starts up, the photovoltaic system starts up, and the AC generator set shuts down;

[0031] When the neutral mode is selected, the DCAC module, the energy storage system, and the photovoltaic system all shut down, and the AC generator set can start up / stop. Description of the drawings:

[0032] Figure 1 It is a topology schematic diagram of an energy-saving system of a large lifting ship in an embodiment of the present invention;

[0033] Figure 2 It is a topology schematic diagram of the energy storage system in the energy-saving system in another embodiment of the present invention;

[0034] Figure 3 It is a topology schematic diagram of the photovoltaic system in the energy storage system in another embodiment of the present invention.

[0035] Reference numerals:

[0036] Integrated energy-saving control cabinet 1

[0037] Energy management system 2

[0038] DCDC module 3

[0039] DCAC module 4

[0040] AC power distribution system 5

[0041] Power station management system 6

[0042] Energy storage system 7

[0043] Energy storage unit cluster 7.1

[0044] Energy storage high - voltage control box 7.2

[0045] Domain management unit 7.3

[0046] High - voltage busbar box 7.4

[0047] Driver's cab display panel 7.5

[0048] Central control room HMI 7.6

[0049] Photovoltaic system 8

[0050] Photovoltaic inverter integrated machine 8.1

[0051] Photovoltaic busbar box 8.2

[0052] Photovoltaic modules and brackets 8.3

[0053] Wind power generation system 9

[0054] Tidal energy system 10

[0055] Monitoring and protection system 11

[0056] Isolation transformer 12 Specific embodiments:

[0057] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0058] Reference is made herein to the various solutions and features of the present application with reference to the accompanying drawings.

[0059] These and other features of the present application will become apparent from the following description of the preferred forms of the embodiments given as non - limiting examples with reference to the accompanying drawings.

[0060] It should also be understood that although the present application has been described with reference to some specific examples, those skilled in the art can surely implement many other equivalent forms of the present application, which have the features as described in the claims and thus are all within the protection scope defined thereby.

[0061] When combined with the accompanying drawings, the above - mentioned and other aspects, features and advantages of the present application will become more apparent in view of the following detailed description.

[0062] Specific embodiments of the present application will be described hereinafter with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of the present application and can be implemented in various ways. Well-known and / or repetitive functions and structures are not described in detail to clarify the true intent based on the user's historical operations and to avoid obscuring the present application with unnecessary or redundant details. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but are merely used as a basis and representative basis for the claims to teach those skilled in the art to use the present application in substantially any suitable detailed structure in a variety of ways.

[0063] This specification may use the phrases "in one embodiment", "in another embodiment", "in yet another embodiment", or "in other embodiments", each of which may refer to one or more of the same or different embodiments according to the present application.

[0064] The present application is a large lifting ship energy-saving system and control method, and the system can play its energy-saving role during the entire operation cycle of the ship, such as berthing for living, mooring for work, and lifting operations. The energy management system and control method ensure the reliability and applicability of the system.

[0065] Figure 1 It is a topological schematic diagram of a large lifting ship energy-saving system in an embodiment of the present invention; Figure 2 It is a topological schematic diagram of the energy storage system in the energy-saving system in another embodiment of the present invention; Figure 3 It is a topological schematic diagram of the photovoltaic system in the energy storage system in another embodiment of the present invention.

[0066] In one embodiment, the present invention is a large lifting ship energy-saving system, and the system can play its energy-saving role during the entire operation cycle of the ship, such as berthing for living, mooring for work, and lifting operations. The energy management system and control method ensure the reliability and applicability of the system.

[0067] The present invention provides a large lifting ship energy-saving system, and the large lifting ship energy-saving system includes an integrated energy-saving control cabinet 1, an energy storage system 7, a photovoltaic system 8, and a variety of energy-saving systems;

[0068] The integrated energy-saving control cabinet 1 includes a plurality of DCDC modules 3, and the DC bus is electrically connected to the external electrical equipment through the DCDC modules 3. The integrated energy-saving control cabinet 1 has an energy management system 2;

[0069] The energy storage system 7 is controlled by the energy management system 2, and the energy storage system 7 is electrically connected to the DC bus through the DCDC modules 3;

[0070] The photovoltaic system 8 is electrically connected to the energy management system 2 and is electrically connected to the DC bus through the DCDC modules 3;

[0071] A plurality of the energy-saving systems are electrically connected to the DC bus through the DCDC module 3.

[0072] In addition to the above description, the energy storage system 7 further includes a supercapacitor system, which consists of an energy storage / supercapacitor cluster and an energy storage / supercapacitor management system. The energy storage / supercapacitor management system communicates with the energy management system. The charge / discharge state and charge / discharge power of the energy storage / supercapacitor are controlled by the instructions of the energy management system; the operating parameters, health status, state of charge, and alarm and security information of the energy storage / supercapacitor are transmitted to the energy management system.

[0073] For the energy-saving system of the large lifting ship, its integrated energy-saving control cabinet 1 is composed of an energy storage DCDC screen, a photovoltaic DCDC screen, a wind power reserved screen, a wave energy reserved screen, a DCAC inverter screen, and a control screen. The energy storage system and the photovoltaic system are connected to the DC bus bar in the energy-saving control cabinet through filters, DCDC modules, fuses, and circuit breakers in their respective control screens; the DC bus outputs AC electric energy through circuit breakers, fuses, DCAC rectifier modules, and filters, and is connected to the AC power grid of the lifting ship through an isolation transformer; the hardware of the energy management system is assembled in the control screen of the energy-saving control cabinet and consists of electronic components such as an engineering programming logic controller, an IO module, and a communication module.

[0074] For the energy-saving system of the large lifting ship, the energy management system 2 serves as the control core: manages the operating states of the energy storage and photovoltaic systems; realizes the associated control with the AC power grid power station management system; provides necessary alarm and security information for the whole ship's monitoring and alarm system; and visually displays the energy-saving effect of clean energy.

[0075] ESS, that is, the energy management system 2, serves as the control core of the energy-saving system and coordinately controls the PMS of each power drive module, energy storage system, photovoltaic system, and AC system in the energy-saving control cabinet. ESS has three control positions: manual, semi-automatic, and automatic. When in the "manual" position, the control authority of each power drive module, energy storage system, and photovoltaic system belongs to the buttons on each screen; when in the "semi-automatic" position, the control authority of each power drive module, energy storage system, and photovoltaic system belongs to the touch-type human-machine interface (HMI) of the ESS system, and the operator controls through the HMI; when in the "automatic" position, the control of each power drive module, energy storage system, and photovoltaic system is automatically judged according to the actual situation, and the start and stop of the AC unit are realized through the communication between ESS and PMS. The three control positions can be selected and confirmed through a knob or the HMI screen.

[0076] In one embodiment, a plurality of the energy-saving systems include a wind power generation system 9 and a tidal energy system 10.

[0077] The described energy-saving system for large lifting vessels has reserved a wind power interface. The wind power device supplies electrical energy to the DC bus through the DCDC rectifier device in the wind power reserved panel and stores it in the energy storage unit through the DCDC converter unit.

[0078] The DCDC module 3 includes a photovoltaic DCDC module, a reserved wind energy DCDC module, and a reserved tidal energy DCDC module, which are applied to different docking situations. Finally, the energy is collected into the integrated energy-saving control cabinet 1. This system has reserved DCDC for wind energy and tidal energy to ensure the expansion of subsequent clean energy.

[0079] In one embodiment, the energy-saving system for large lifting vessels further includes an AC power distribution system 5. The AC power distribution system 5 is electrically connected to the DCAC module 4 through an isolation transformer 12 and then electrically connected to the DC bus.

[0080] For the described photovoltaic system of large lifting vessels, the primary side of the isolation transformer is connected to the energy-saving control cabinet, and the secondary side is connected to the ship's AC power grid.

[0081] As a further improvement of the above solution, the energy-saving system is configured with an isolation transformer to ensure that the power quality and voltage level from the integrated energy-saving control cabinet to the ship's AC power grid meet the usage requirements. It ensures the electrical isolation between the energy-saving system and the AC system and meets the relevant short-circuit and harmonic power calculation requirements.

[0082] In one embodiment, the energy-saving system for large lifting vessels includes a monitoring and protection system 11;

[0083] The monitoring and protection system 11 is communicatively connected to the energy management system through MODBUS RTU

[0084] In one embodiment, the energy-saving system for large lifting vessels includes a power station management system 6;

[0085] The power station management system 6 is electrically connected to the energy management system 2.

[0086] In one embodiment, the energy storage system 7 includes a domain management unit 7.3, a control room display panel 7.5, a centralized control room HMI 7.6, a high-voltage control box 7.2, an energy storage unit cluster 7.1, and a high-voltage busbar box 7.4;

[0087] The control room display panel 7.5 is electrically connected to the domain management unit 7.3;

[0088] The centralized control room HMI 7.6 is electrically connected to the domain management unit 7.3;

[0089] The high-voltage control box 7.2 is electrically connected to the domain management unit 7.3;

[0090] The energy storage unit cluster 7.1 is electrically connected to the high-voltage control box 7.2;

[0091] The high-voltage busbar box 7.4 is electrically connected to the high-voltage control box 7.2, and the high-voltage busbar box 7.4 is electrically connected to the DC bus through the DCDC module 3;

[0092] The domain management unit 7.3 is electrically connected to the energy management system 2.

[0093] The control function of the energy-saving system is realized by the energy management system (ESS) 2. The energy management system (ESS) 2 is composed of electronic components such as an engineering programming logic controller, an HMI interface, an IO module, and a communication module. It controls each electric drive module and communicates and cooperates with the power station management system (PMS) 6 of the AC power grid to achieve various energy-saving functions. The operation and alarm parameters of equipment such as the energy storage system, the 7 photovoltaic system 8, the integrated energy-saving cabinet 1, and the isolation transformer 12 are communicated to the ship monitoring and alarm system (AMS) 11 by the ESS for unified display. The ESS hardware and each electric drive component are arranged in the corresponding screen of the energy-saving control cabinet. The energy-saving control cabinet is composed of an energy storage DCDC screen, a photovoltaic DCDC screen, a wind power reserved screen, a wave energy reserved screen, a DCAC inverter screen, and a control screen.

[0094] In one embodiment, the photovoltaic system 8 includes a photovoltaic busbar box 8.2, photovoltaic modules and brackets 8.3, and a photovoltaic inverter integrated machine 8.1. The photovoltaic modules include flexible photovoltaic modules or hard-board photovoltaic modules, which are installed on the photovoltaic brackets and are bolted or welded to the hull. The photovoltaic modules should be arranged in the vacant area under the projection of the crane ship's boom to avoid oil stains dripping and polluting the surface of the photovoltaic modules, and a flushing system should be configured to meet the regular maintenance and cleaning requirements of the photovoltaic modules.

[0095] The photovoltaic bracket 8.3 should ensure the fixation of the photovoltaic modules. The bracket and its connectors are made of corrosion-resistant materials, and the lifting distance of the bracket should meet the maintenance space of the photovoltaic modules. The layout angle and strength of the bracket should resist a wind speed greater than or equal to 50 km / h.

[0096] The photovoltaic busbar cabinet realizes the function of parallel output of multiple clusters of photovoltaic modules, in order to save the overall space of the photovoltaic system or integrate the photovoltaic controller and the photovoltaic busbar cabinet into one cabinet.

[0097] The photovoltaic controller communicates with the energy management system, and the start / stop of the photovoltaic system is controlled by the energy management system; the working parameters and alarm and security information of the photovoltaic system are transmitted to the energy management system.

[0098] The photovoltaic controller adopts the maximum power point tracking control method, and the photovoltaic controller receives the given photovoltaic working cut-off voltage and output power signals from the energy management system.

[0099] Specifically, its photovoltaic system consists of parts such as a photovoltaic inverter integrated unit 8.1, a photovoltaic busbar cabinet 8.2, and photovoltaic modules and brackets 8.3. The large crane ship type has the characteristics of a wide and flat deck surface. The photovoltaic modules and brackets 8.3 are arranged at flat structures such as the roof of the living area, the roof of the cab, and the stern deck. The photovoltaic modules include flexible modules and rigid modules, which are fixed on the photovoltaic brackets through special glue or connectors. The photovoltaic brackets are connected to the hull structure by welding or bolts, and the strength of the photovoltaic brackets can withstand a 7-level wind (50 km / h). The photovoltaic modules are connected in series into clusters to meet the voltage requirements. Multiple clusters are connected in parallel and uniformly connected to a photovoltaic busbar box 8.2 to become a single output, which is then connected to the photovoltaic inverter integrated unit 8.1 and further connected to the photovoltaic DCDC for boost and voltage stabilization control to provide energy to the energy-saving control cabinet. The inverter integrated unit 8.1 uses a maximum power point tracking control algorithm to ensure the maximum power output under available photovoltaic conditions. The start-stop control of the inverter integrated unit 8.1 accepts the communication control of the ESS. At the same time, it has an off-grid controller with functions such as good input high-voltage disconnection and reconnection, under-voltage alarm and recovery, environmental temperature display, and automatic temperature compensation function.

[0100] In one embodiment, the domain management unit communicates with the high-voltage control box, the high-voltage control box and the energy storage unit cluster, and the domain management unit communicates with the energy management system and the domain management unit communicates with the photovoltaic inverter integrated unit through the CAN method;

[0101] The monitoring and protection system communicates with the energy management system through the MODBUS RTU method;

[0102] The cab display panel and the centralized control room HMI communicate with the domain management box through the Ethernet method respectively, and the power station management system communicates with the energy management system through the Ethernet method.

[0103] In one embodiment, the energy storage unit cluster includes multiple clusters of energy storage units. The energy storage unit includes a single-pack battery or capacitor. The single-pack battery or capacitor is connected in series into a cluster, and the energy storage units are connected in parallel.

[0104] The energy storage unit 7.1 includes a battery and a supercapacitor. Its architecture is that a single-pack battery or capacitor is connected in series into a cluster, and multiple clusters are connected in parallel into a group. Each group is an independent energy storage system. The control of the energy storage system adopts a three-level management architecture. The smallest control unit is a single-pack battery or capacitor. Each cluster is configured with a high-voltage control box 7.2 as the secondary management unit. After multiple clusters are grouped, a domain management box 7.3 is configured as the tertiary management unit to manage the charging, discharging, protection, temperature monitoring, etc. of the energy storage unit at multiple levels. The communication and control of the energy storage system 7 with the energy management system (ESS) 2 are only completed by the domain management box 7.3.

[0105] Based on Tables 1 and 2 in the following text, in one embodiment, the present invention further provides a control method for an energy-saving system of a large lifting ship. Based on the energy-saving system of the large lifting ship, the control method includes:

[0106] Select different working modes according to different working conditions. The working modes include an energy-saving mode, a green charging mode, and a neutral gear mode;

[0107] When the energy-saving mode is selected, the DCAC module starts and is connected to the AC system in parallel, the energy storage system starts, the photovoltaic system can start / stop, and the AC generator set can start / stop;

[0108] When the green charging mode is selected, the DCAC module stops, the energy-saving system is isolated from the AC system, the energy storage system starts, the photovoltaic system starts, and the AC generator set stops;

[0109] When the neutral gear mode is selected, the DCAC module, the energy storage system, and the photovoltaic system all stop, and the AC generator set can start / stop.

[0110] The control mode of the AC power grid power station management system (PMS) includes a working mode and a living mode. Various energy-saving functions of the energy-saving system can be automatically realized through the mode selection of the PMS and the ESS.

[0111] The PMS is in the working mode and the ESS is in the energy-saving mode. The energy-saving system automatically controls the low-load energy efficiency optimization of the AC generator set: The PMS sets the low-load working threshold of the generator set. When the AC on-grid load is lower than this threshold, it automatically enters the "low-load energy efficiency optimization of the AC generator set" function. Set the best energy consumption operation load rate of the AC generator set. The PMS calculates the difference according to the actual AC on-grid load and communicates the energy storage charging power to the ESS. The ESS judges that the energy storage SOC is in the chargeable condition and can control the AC generator set to charge the battery; if the photovoltaic has the on-grid charging condition, the photovoltaic inverter integrated machine communicates the MPPT calculated power to the ESS; Combining the AC charging power and the photovoltaic charging power, the ESS controls the current mode of the energy storage DCDC module for charging and automatically exits this mode after the energy storage SOC reaches the upper limit threshold.

[0112] The PMS is in the working mode and the ESS is in the energy-saving mode. The energy-saving system automatically controls the suppression of high-load fluctuations of the AC generator set: The PMS sets the high-load working threshold of the generator set. When the AC on-grid load is higher than this threshold, it automatically enters the "suppression of high-load fluctuations of the AC generator set" function. Set the best energy consumption load rate of the AC generator set. The ESS sets the droop characteristics of the DCAC and the AC generator set as DCAC priority. If there is a sudden increase in the load on the AC power grid, the bus voltage of the energy-saving system will drop first. The ESS controls the energy storage system DCDC in the constant voltage mode. The energy storage system quickly responds to the power deficit of the fluctuation system and automatically exits this mode after the energy storage SOC reaches the lower limit threshold.

[0113] The PMS is in the working mode and the ESS is in the energy-saving mode. Systems such as the crane and winch will issue a "potential energy recovery" mode command during the process of lowering heavy objects. At this time, after the ESS determines that the energy storage SOC meets the requirements, it enters the "hoisting potential energy recovery" function. The ESS controls the energy storage DCDC to charge with the maximum current, recovering the potential energy of the heavy object to the energy storage system. When the process of lowering the heavy object is completed, the "potential energy recovery" command will be stopped, and the ESS controls the DCDC to exit the maximum current charging, and automatically judges according to the AC grid load to achieve "optimization of low-load energy efficiency of AC units" or "smoothing of high-load fluctuations of AC units".

[0114] The PMS is in the working mode and the ESS is in the green charging mode. The ESS controls the DCAC module to stop, disconnecting the energy-saving system from the AC system. At this time, the PV must have the condition of on-grid charging. The PV inverter integrated machine communicates with the ESS to calculate the MPPT power. The ESS controls the energy system DCDC to convert solar energy into electrical energy and store it in the energy storage system in the constant voltage mode, and automatically exits this mode after the energy storage SOC reaches the upper limit threshold.

[0115] The PMS is in the living mode and the ESS is in the energy-saving mode. "Energy storage for living power supply" function: When the energy storage system SOC meets the discharge condition, the ESS communicates with the PMS to stop the unit, and the daily load of the whole ship is powered by the energy storage system and the PV system (if conditions permit); "Energy storage charging" function: After the energy storage SOC does not meet the discharge condition, the ESS communicates with the PMS to start the unit, and the unit is responsible for charging the daily load of the whole ship and the energy storage system. Controlling the charging power with the best energy consumption as the goal, the PMS calculates the difference according to the actual AC daily load, obtains the energy storage charging power and communicates it to the ESS. The ESS judges that the energy storage SOC is in the chargeable condition and can control the AC unit to charge the battery; if the PV has the condition of on-grid charging, the PV inverter integrated machine communicates with the ESS to calculate the MPPT power; combining the AC charging power and the PV charging power, the ESS controls the energy storage DCDC module to charge in the current mode and automatically exits this mode after the energy storage SOC reaches the upper limit threshold. The above two functions are automatically cycled based on the state of the energy storage system SOC.

[0116] The judgment basis for the energy-saving working mode of the large crane ship energy-saving system is as follows: The energy-saving system energy storage system operates, the PV system operates, and the DCAC rectifier module operates and is connected to the AC distribution board. At this time, the energy management system can control the energy storage system and the PV system to supply power to the AC distribution board, or control the unit and the PV system to charge the battery pack.

[0117] The judgment basis for the green charging mode of the energy-saving system of the large crane ship is as follows: when the energy storage system is operating, the photovoltaic system is operating, the DCAC rectifier module is shut down and the AC distribution board circuit breaker is disconnected, and the energy management system controls the photovoltaic system to charge the battery pack.

[0118] The judgment basis for the neutral gear mode of the energy-saving system of the large crane ship is as follows: when the energy storage system is shut down, the photovoltaic system is shut down, the DCAC rectifier module is shut down and the AC distribution board is disconnected, and the AC distribution board is powered by the unit.

[0119] For the large crane ship, the working modes of the AC system power station management system are divided into the working mode and the living mode.

[0120] When the AC system power station management system is in the working mode and the energy management system of the energy-saving system is in the energy-saving mode, the functions of the energy-saving system include: optimizing the energy efficiency of the AC unit at low load, suppressing the AC high-load fluctuation, and recovering the potential energy of the suspended load.

[0121] When the AC system power station management system is in the working mode and the energy management system of the energy-saving system is in the green charging mode, the functions of the energy-saving system include: off-grid charging of the photovoltaic system.

[0122] When the AC system power station management system is in the living mode and the energy management system of the energy-saving system is in the energy-saving mode, the functions of the energy-saving system include: power supply for living by the energy storage system and charging of the energy storage system.

[0123] The energy-saving system of the large crane ship - the function of optimizing the energy efficiency of the AC unit at low load: control the inverter device of the energy-saving system to be connected to the AC system power station in parallel. When the large crane ship is in low-load working conditions such as standby waiting or light suspended load, the energy management system controls the AC power station to maintain the best fuel consumption rate control. Keep the power station load unchanged, and charge the energy storage system with the differential power to improve the comprehensive energy efficiency.

[0124] The energy-saving system of the large crane ship - the function of suppressing the AC high-load fluctuation: the control function of the energy-saving system of the large crane ship: control the inverter device of the energy-saving system to be connected to the AC system power station in parallel, and set the constant voltage control on the AC side of the inverter device. When the load suddenly changes during the operation of the crane ship, resulting in a sudden drop in the AC grid voltage, since the constant voltage on the AC side of the inverter can quickly supplement the energy gap, reduce the speed regulation and load regulation actions of the AC power station, improve the economy, and is beneficial to the equipment maintenance.

[0125] The energy-saving system of the large crane ship - the function of recovering the potential energy of the suspended load: in typical working conditions of the suspended load descending or the leg descending of the crane ship, provide the process signal to the energy management system, control the inverter device and the DCDC device to enter the large-current charging mode, and prepare the signal to be fed back to the crane or the lifting control unit to start the working conditions of the suspended load descending or the leg descending, convert the gravitational potential energy into electrical energy and collect it into the energy storage battery. After the process is completed, give the completion signal and exit the large-current charging mode.

[0126] The energy-saving system for large lifting vessels - Photovoltaic off-grid charging: When the AC system is operating at high power, the energy management system of the energy-saving system can be selected to control the disconnection from the AC system and turn off the DCAC. Under sufficient sunlight conditions, the energy storage system and the photovoltaic system of the energy-saving system operate independently of the AC system. The energy storage system is controlled to be in the charging mode, converting solar energy into electrical energy for storage.

[0127] The energy-saving system for large lifting vessels - Energy storage for life power supply: The photovoltaic system and the energy storage system jointly supply power to the AC system. The energy management system controls the inverter device of the energy-saving system to be connected to the AC system power station in parallel. The converter devices of the energy storage system and the photovoltaic system are set to give priority to photovoltaic output through droop control, and the energy storage system serves as an energy supplement. In the absence of sunlight, the photovoltaic system controller automatically cuts off under-voltage, and the entire system is powered by the energy storage system, achieving quietness and greenness.

[0128] The energy-saving system for large lifting vessels - Energy storage charging: When the SOC of the energy storage system is too low to support the system power consumption, the energy management system controls the start-up of the AC unit, and the energy storage system is supplemented with energy through parallel connection via DCAC. This function controls the charging power in accordance with the principle of the best fuel consumption of the unit. After the SOC of the energy storage system reaches the upper limit, the charging automatically stops, the unit exits and shuts down, and the system resumes energy storage for life power supply.

[0129] Table 1:

[0130] ESS mode Energy-saving mode Green charging mode Neutral gear Device DCAC √ × × Energy storage √ √ × Photovoltaic / / √ × AC unit / / × / /

[0131] Table 2:

[0132]

[0133] Beneficial effects:

[0134] 1. Large lifting vessels are very important as important marine equipment. This type of vessel has the advantage of a wide range of engineering operation capabilities, but there are also contradictions in high energy consumption in working conditions such as berthing for life, waiting during operations, and low-load standby. Moreover, the low-load conditions during berthing for life and waiting during operations account for more than 80% of the entire working condition task profile. Designing an energy-saving system and an integrated energy-saving control method that include a composite energy storage system can greatly improve the overall ship energy efficiency through scenarios such as energy storage peak shaving and valley filling, potential energy recovery, and optimal fuel consumption control of the unit.

[0135] 2. The operation process of conventional large lifting vessels can be roughly divided into: hoisting, ship movement, positioning, and lowering. During the lowering process, the potential energy of the heavy object being lowered is often converted into heat energy and dissipated. Designing an energy-saving device with a composite energy storage system can form electrical energy feedback and storage during the process of lowering the heavy object, which helps to improve the ship energy efficiency under operating conditions.

[0136] 3. Based on the characteristics of the large lifting ship's hull form, the structural advantages of the superstructure such as the cab, winch room, and boom platform being flat, regular in shape, and having a large area, a energy-saving system based on a photovoltaic device and a composite energy storage system is designed. By using photovoltaic energy storage and discharging the stored energy at night, it can meet the electricity demand of the basic auxiliary system and the crew's living needs, which helps to improve the overall ship energy efficiency and the crew's living comfort.

[0137] 4. Based on the characteristics of the large lifting ship's hull form, there is abundant wind energy and wave energy in the operation area of this hull form. The system is configured with interfaces for wind power and wave power generation devices, and the energy can be grid-connected through the reserved DCDC unit, providing a hardware foundation for further improvement of energy efficiency in the future.

[0138] The above embodiments are only exemplary embodiments of the present invention and are not used to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present invention.

Claims

1. A large crane ship energy saving system, characterized in that: The large crane ship energy saving system comprises: An integrated energy-saving control cabinet (1), comprising a plurality of DCDC modules (3), wherein a DC bus is electrically connected to an external electrical system via the DCDC modules (3), and the integrated energy-saving control cabinet (1) has an energy management system (2); an energy storage system (7), which is controlled by the energy management system (2), and the energy storage system (7) is electrically connected to the DC bus through the DCDC module (3); a photovoltaic system (8), which is electrically connected to the energy management system (2) and is electrically connected to the DC bus through the DCDC module (3); A plurality of energy-saving systems are electrically connected to the DC bus through the DCDC module (3).

2. The large crane ship energy saving system according to claim 1, characterized in that: The various energy-saving systems include a wind power generation system (9) and a tidal current energy system (10).

3. The large crane ship energy saving system according to claim 2, characterized in that: The large crane ship energy saving system also includes: An AC power distribution system (5) is electrically connected to the DCAC module (3) via an isolation transformer (12), and further electrically connected to the DC bus.

4. The large crane ship energy saving system according to claim 3 is characterized in that: The large crane ship energy saving system comprises: A monitoring and protection system (11) is electrically connected to the DC bus.

5. The large crane ship energy saving system according to claim 4, characterized in that: The large crane ship energy saving system comprises: A power plant management system (6) is electrically connected to the energy management system (2).

6. The large crane ship energy saving system according to claim 5, characterized in that: The energy storage system (7) comprises: A domain management unit (7.3); a control room display panel (7.5), which is electrically connected to the domain management unit (7.3); A centralized control room HMI (7.6), which is electrically connected to the domain management unit (7.3); a high-voltage control box (7.2), which is electrically connected to the domain management unit (7.3); an energy storage unit cluster (7.1), which is electrically connected to the high-voltage control box (7.2); a high-voltage combiner box (7.4), which is electrically connected to the high-voltage control box (7.2), and the high-voltage combiner box (7.4) is electrically connected to the DC busbar via the DCDC module (3); The domain management unit (7.3) is electrically connected to the energy management system (2).

7. The large crane ship energy saving system according to claim 6, characterized in that: The photovoltaic system (8) comprises a photovoltaic combiner box (8.2), photovoltaic components and brackets (8.3), and a photovoltaic inverter (8.1).

8. The large crane ship energy saving system according to claim 7, characterized in that: The domain management unit (7.3) communicates with the high-voltage control box (7.2), the high-voltage control box (7.2) and the energy storage unit cluster (7.1), the domain management unit (7.3) and the energy management system (2), and the domain management unit (7.3) and the photovoltaic inverter (8.1) via CAN; The monitoring and protection system (11) communicates with the energy management system (2) via MODBUS RTU; The control room display panel (7.5) and the centralized control room HMI (7.6) communicate with the domain management unit (7.3) respectively via Ethernet, and the power station management system communicates with the energy management system (2) via Ethernet.

9. The large crane ship energy saving system according to claim 8, characterized in that: The energy storage unit cluster (7.1) comprises a plurality of clusters of energy storage units, wherein the energy storage units comprise single-pack batteries or capacitors, wherein the single-pack batteries or capacitors are connected in series to form a cluster, and the energy storage units are connected in parallel.

10. A control method for a large crane ship energy-saving system, characterized in that: Based on the large crane ship energy saving system according to any one of claims 5 to 9, the control method comprises: According to different working conditions, different working modes are selected, and the working modes include energy-saving mode, green charging mode, and neutral mode; When the energy-saving mode is selected, the DCAC module (3) is started and connected to the AC system, the energy storage system (7) is started, the photovoltaic system (8) can be started / stopped, and the AC unit can be started / stopped; When the green charging mode is selected, the DCAC module shutdown energy-saving system is isolated from the AC system, the energy storage system is started, the photovoltaic system is started, and the AC unit is shut down; When the neutral mode is selected, the DCAC module, energy storage system, and photovoltaic system are all shut down, and the AC unit can be started / stopped.

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