A ship shore-based bidirectional charging and discharging system
By designing a bidirectional charging and discharging system for shore-based ships, bidirectional energy conversion between AC and DC was achieved, solving the problem of low energy utilization efficiency in existing shore power systems, improving energy utilization efficiency and system scalability, and reducing operating costs and carbon emissions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAMEN FREE TRADE ZONE PORT ELECTRIC POWER CO LTD
- Filing Date
- 2025-06-06
- Publication Date
- 2026-06-19
AI Technical Summary
Existing shore power systems are mostly unidirectional power supply modes, which cannot effectively utilize the surplus electrical energy of ship energy storage systems, resulting in low energy utilization efficiency, increased operating costs, and limited system economic and environmental benefits.
A bidirectional charging and discharging system for ship-shore applications was designed, comprising a high-voltage input module, an AC power distribution module, an AC/DC conversion module, and cable equipment. The system achieves bidirectional energy conversion between AC and DC through the bidirectional AC/DC conversion module, integrates AC and DC prefabricated compartments to improve the system's modularity and safety, and employs space vector modulation technology to control the converter unit to achieve bidirectional energy flow.
It enables bidirectional energy conversion between ships and shore power systems, improves energy efficiency, reduces peak shaving and valley filling, reduces the demand for ship fuel power generation, lowers operating costs, and enhances the stability of the power grid and the port's low-carbon goals.
Smart Images
Figure CN224385093U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of ship power supply technology, and in particular to a bidirectional charging and discharging system for ship shore-based applications. Background Technology
[0002] With the sustained and rapid development of my country's economy, the frequency and density of ship berthing at docks have increased significantly. After berthing, ships typically shut down their main engines and start auxiliary engines to generate electricity to meet the daily power needs of their onboard equipment. However, these auxiliary engines mostly use low-quality heavy oil as fuel, resulting in poor combustion efficiency and the emission of large amounts of pollutants, such as sulfur oxides, nitrogen oxides, and other particulate matter. This makes them a serious source of pollution for port cities, negatively impacting the surrounding ecological environment and the quality of life for residents. Simultaneously, ship-fired fuel oil power generation is inefficient, suffers significant losses, and excess electricity cannot be stored, leading to enormous energy waste and a substantial increase in ship operating costs.
[0003] In recent years, the level of ship electrification has been continuously improving, and port shore power technology has also developed accordingly. Currently, the widely used shore power supply systems mainly rely on unidirectional AC transmission, which can only meet the basic power needs of shipboard equipment during berthing. However, with the increasing popularity of new energy ships, especially hybrid and pure electric ships, ships not only need shore power supply systems but also urgently require efficient and intelligent charging and discharging management of ship energy storage systems to improve energy utilization efficiency and reduce operating costs.
[0004] However, existing shore power systems mostly adopt a unidirectional power supply mode, which can only realize the one-way power transmission from the shore-based power grid to the ship. It cannot effectively utilize the surplus power of the ship's energy storage system, resulting in low energy utilization efficiency and limiting the economic and environmental benefits of the system. In addition, traditional AC / DC conversion devices usually use independent rectifier and inverter equipment, which not only increases the number of devices and the footprint, but also increases the complexity of installation and maintenance and the cost of the system, thus restricting the large-scale promotion and application of shore power technology. Utility Model Content
[0005] To overcome the shortcomings of existing technologies, the technical problem to be solved by this utility model is to propose a bidirectional charging and discharging system for ship-shore applications, adopting the following technical solution:
[0006] A ship-to-shore bidirectional charging and discharging system includes a high-voltage input module and an AC power distribution module. The high-voltage input module is connected to a shore power source and transmits a high-voltage input signal to the AC power distribution module. The AC power distribution module is connected to a low-voltage power distribution module via a first transformer and to a shore power pile to supply power to the ship. The AC power distribution module is further connected to an AC / DC conversion module via a second transformer. The AC / DC conversion module is connected to the ship via cable equipment.
[0007] The aforementioned AC / DC conversion module includes a bidirectional AC / DC conversion module. When the ship needs to charge, the bidirectional AC / DC conversion module rectifies the AC power into DC power and outputs it to the ship's energy storage unit through cable equipment. When the ship needs to discharge, the bidirectional AC / DC conversion module inverts the DC power from the energy storage unit into AC power and feeds it back to the shore power grid through the AC power distribution module.
[0008] As a further improvement, the shore-based system is equipped with both AC and DC prefabricated modules; among them,
[0009] The aforementioned prefabricated AC module is equipped with a main feeder cabinet, a high-voltage incoming cabinet, a metering cabinet, a first feeder cabinet, a second feeder cabinet, a first transformer cabinet, a low-voltage incoming cabinet, and a low-voltage incoming / outgoing cabinet. The main feeder cabinet and the high-voltage incoming cabinet form the high-voltage input module. The metering cabinet, the first feeder cabinet, and the second feeder cabinet form the AC power distribution module. The first transformer cabinet contains the first transformer. The low-voltage incoming cabinet and the low-voltage incoming / outgoing cabinet form the low-voltage power distribution module.
[0010] The aforementioned DC prefabricated compartment is equipped with a second transformer cabinet, a rectifier cabinet, and a DC feeder cabinet. The second transformer cabinet is equipped with the aforementioned second transformer, and the rectifier cabinet is equipped with the aforementioned AC / DC conversion module. The aforementioned DC feeder cabinet is connected to the aforementioned cable equipment.
[0011] As a further improvement, the aforementioned bidirectional AC / DC conversion module includes a converter unit, a filter unit, and a control unit. The control unit uses space vector modulation technology to control the converter unit to achieve bidirectional flow between AC and DC.
[0012] As a further improvement, the first transformer is a three-phase isolation transformer. The primary side of the three-phase isolation transformer is connected to the first feeder cabinet, and the two secondary sides are respectively connected to the low-voltage incoming cabinet and the low-voltage incoming and outgoing cabinet. The low-voltage incoming cabinet is also connected to the UPS power supply and the high-voltage cabinet heating power supply.
[0013] As a further improvement, the input voltage of the high-voltage input module is 10kV AC. The first transformer steps down the input voltage to 0.4kV and outputs it to the low-voltage distribution module. The second transformer steps down the input voltage to 0.66kV and outputs it to the AC-DC conversion module.
[0014] As a further improvement, the aforementioned cable equipment includes cable winding and unwinding drums, cable tracks, and automatic plugging and unplugging devices for enabling rapid connection of cables between shore and ship.
[0015] As a further improvement, the aforementioned low-voltage power distribution module is connected to three of the aforementioned shore power piles and is equipped with a spare interface.
[0016] As a further improvement, the second transformer is a three-phase isolation transformer, with its primary side connected to the AC power distribution module. The rectifier cabinet is equipped with two bidirectional AC / DC conversion modules, whose input terminals are respectively connected to the two secondary sides of the second transformer.
[0017] As a further improvement, the aforementioned DC feeder cabinet is equipped with a three-in-two switch assembly for electrical interlocking. The three-in-two switch assembly includes a first output switch and a second output switch located at the output terminals of the two aforementioned bidirectional AC / DC conversion modules, and a tie switch connected in parallel between the first output switch and the second output switch. By controlling the on / off state of the tie switch, the parallel connection or isolation of the two AC / DC conversion paths can be achieved.
[0018] Compared with the prior art, the beneficial effects of this utility model are:
[0019] Firstly, this utility model integrates the main feeder cabinet, high-voltage incoming cabinet, metering cabinet, first feeder cabinet, second feeder cabinet, first transformer cabinet, low-voltage incoming cabinet, and low-voltage incoming / outgoing cabinet into the AC prefabricated compartment, and integrates the second transformer cabinet, rectifier cabinet, and DC feeder cabinet into the DC prefabricated compartment, thus constructing a highly modular system structure. This forms a safe isolation between the AC and DC sides, improves operational safety, reduces mutual interference between different electrical equipment, enhances the ease of system installation and maintenance efficiency, facilitates rapid on-site assembly and commissioning during port deployment, and simultaneously enhances the system's scalability and operational stability, adapting to various port layouts and upgrade requirements.
[0020] Secondly, this utility model includes a bidirectional AC / DC conversion module. The control unit controls the converter unit through space vector modulation technology to achieve bidirectional energy conversion between AC and DC. This structure can not only rectify the shore-side AC power into DC power to charge the ship's energy storage unit during ship berthing, but also, under specific conditions, invert the DC power from the ship's energy storage unit into AC power and feed it back to the AC power distribution module. This significantly improves the dynamic allocation capability of energy between ship and shore, realizing multiple functions such as peak shaving and valley filling, and energy feedback. It effectively improves power utilization efficiency, alleviates the pressure on the port power grid, and helps achieve the port's low-carbon operation goals. Attached Figure Description
[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.
[0022] Figure 1 This is a schematic diagram of the overall structural framework of this utility model;
[0023] Figure 2 This is an electrical connection diagram of an embodiment of the present invention;
[0024] Figure 3 This is an electrical connection diagram of another embodiment of the present invention;
[0025] Figure 4 This is the circuit topology diagram of the AC / DC conversion module of this utility model.
[0026] Figure label:
[0027] 1-High voltage input module; 2-AC power distribution module; 3-First transformer; 4-Low voltage power distribution module; 5-Shore power pile; 6-Second transformer; 7-AC / DC conversion module; 8-DC power supply module; 9-Cable equipment;
[0028] 71-Bidirectional AC / DC converter module; 71a-Converter unit; 71b-Filtering unit; QF1-First output switch; QF2-Second output switch; QF3-Connection switch;
[0029] 100 - AC prefabricated cabin; 200 - DC prefabricated cabin; 300 - Ship;
[0030] 110 - Main feeder cabinet; 120 - High voltage incoming line cabinet; 130 - Metering cabinet; 140 - First feeder cabinet; 150 - Second feeder cabinet; 160 - First transformer cabinet; 170 - Low voltage incoming line cabinet; 180 - Low voltage incoming / outgoing line cabinet;
[0031] 210 - Second transformer cabinet; 220 - Rectifier cabinet; 230 - DC feeder cabinet; 310 - Energy storage unit. Detailed Implementation
[0032] To facilitate understanding by those skilled in the art, the structure of this utility model will now be described in further detail with reference to the accompanying drawings:
[0033] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. The terms "part," "side," "end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model 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; therefore, they should not be construed as limitations on this utility model.
[0034] like Figures 1-3As shown, a shore-based bidirectional charging and discharging system for ships includes a high-voltage input module 1 and an AC power distribution module 2. The high-voltage input module 1 is connected to a shore power source and transmits the high-voltage input signal to the AC power distribution module 2. The AC power distribution module 2 is connected to a low-voltage power distribution module 4 via a first transformer 3, and then connected to a shore power pile 5 to supply power to the ship 300. Through this power supply path, the ship 300 can access the shore power pile 5 to obtain power when docked in port, thereby shutting down the ship's generator set and avoiding emissions and noise. The shore power system is typically connected to the port's high-voltage power distribution network, and the voltage is converted to the level required by the ship 300 through equipment such as step-up / step-down transformers.
[0035] In one embodiment, the shore-side terminal provides a 10kV / 50Hz high-voltage AC power distribution system, which is stepped down to 0.4kV / 50Hz by a first transformer 3. A low-voltage power distribution module 4 is connected to three shore power piles 5 and is equipped with a spare interface. After the vessel 300 berths, it can directly connect to the shore power piles 5 for power supply. Typically, the vessel 300's power supply load includes high-energy-consuming equipment such as lighting, electric propulsion, and refrigeration systems. Replacing fuel-fired power generation with shore power can effectively reduce carbon emissions during berthing.
[0036] Furthermore, such as Figure 1 As shown, the AC distribution module 2 is further connected to the AC / DC conversion module 7 via the second transformer 6, and the AC / DC conversion module 7 is connected to the ship 300 via the cable device 9.
[0037] Specifically, the AC / DC conversion module 7 includes a bidirectional AC / DC conversion module 71. When the ship 300 needs to be charged, the bidirectional AC / DC conversion module 71 rectifies the AC power into DC power and connects to the cable equipment 9 through the DC power supply module 8. The cable equipment 9 connects to the energy storage unit 310 of the ship 300. When the ship 300 needs to be discharged, the bidirectional AC / DC conversion module 71 inverts the DC power of the energy storage unit 310 into AC power and feeds it back to the shore power grid through the AC distribution module 2.
[0038] In one specific embodiment, the second transformer 6 steps down the 10kV / 50Hz voltage to 0.66kV / 50Hz, and outputs 1000V DC power via the AC / DC conversion module 7. This structure effectively utilizes the surplus energy of the ship's 300 energy storage system, improving energy efficiency. During the ship's 300 berthing period, if the energy storage system stores a large amount of energy, this energy can be fed back to the shore power grid, achieving efficient energy utilization and reducing the ship's 300's need for fuel-fired power generation, thus lowering operating costs. Furthermore, the bidirectional charging and discharging system can also achieve peak shaving and valley filling, charging the ship's 300 energy storage system when the grid load is low and feeding the energy back to the grid when the grid load is high, effectively balancing the grid load and improving the economic efficiency and stability of grid operation.
[0039] like Figure 2 In one specific embodiment shown, the shore-based structure is provided with an AC prefabricated cabin 100 and a DC prefabricated cabin 200. The AC prefabricated compartment 100 is equipped with a main feeder cabinet 110, a main feeder cabinet 120, a metering cabinet 130, a first feeder cabinet 140, a second feeder cabinet 150, a first transformer cabinet 160, a low-voltage incoming cabinet 170, and a low-voltage incoming / outgoing cabinet 180. The main feeder cabinets 110 and 120 form a high-voltage input module 1, and the metering cabinets 130, 140, and 150 form an AC power distribution module 2. The first transformer cabinet 160 contains a first transformer 3, and the low-voltage incoming / outgoing cabinets 170 and 180 form a low-voltage power distribution module 4. The DC prefabricated compartment 200 is equipped with a second transformer cabinet 210, a rectifier cabinet 220, and a DC feeder cabinet 230. The second transformer cabinet 210 contains a second transformer 6, and the rectifier cabinet 220 contains an AC / DC conversion module 7. The DC feeder cabinet 230 is connected to cable equipment 9.
[0040] By setting up the AC prefabricated compartment 100 and the DC prefabricated compartment 200, the AC side and the DC side are safely isolated, which improves the safety of operation, reduces the mutual influence between different electrical equipment, reduces the risk of failure, and facilitates the subsequent upgrade or expansion of the system.
[0041] like Figure 4 As shown, the bidirectional AC / DC conversion module 71 includes a converter unit 71a, a filter unit 71b, and a control unit (not shown in the figure). The control unit controls the converter unit 71a to achieve bidirectional flow between AC and DC through space vector modulation technology.
[0042] like Figure 4 As shown, in one embodiment, the converter unit 71a adopts a three-phase full-bridge IGBT topology, consisting of six IGBT power switching devices forming a three-phase inverter bridge. The control unit drives the IGBTs to switch on and off, enabling bidirectional flow between AC and DC. The AC input filter at the input end suppresses high-frequency electromagnetic interference. During rectification, the three-phase AC power is input through EMI 1 and the pre-charge circuit. The control unit uses space vector pulse width modulation to control the IGBT modules, rectifying the AC power into smooth DC power, which is then output to the DC feeder cabinet 230 via the filter unit 71b to charge the ship's 300 energy storage unit 310. During inversion, the DC power from the ship's 300 energy storage unit 310 is inverted via the same bridge circuit under the control of the control unit, driving the IGBT devices to generate three-phase AC power. After processing by EMI 2, it is fed back to the grid via the AC distribution module 2.
[0043] like Figure 2As shown, the first transformer 3 is a three-phase isolation transformer. The primary side of the three-phase isolation transformer is connected to the first feeder cabinet 140, and the two secondary sides are connected to the low-voltage incoming cabinet 170 and the low-voltage incoming and outgoing cabinet 180, respectively. The low-voltage incoming cabinet 170 is also connected to the UPS power supply and the high-voltage cabinet heating power supply.
[0044] The aforementioned cable equipment 9 includes a cable winding and unwinding drum, a cable track, and an automatic plugging and unplugging device, used to achieve rapid connection of cables between shore and ship.
[0045] like Figure 3 As shown, in another embodiment, the second transformer 6 is a three-phase isolation transformer, with its primary side connected to the AC distribution module 2. The rectifier cabinet 220 is equipped with two bidirectional AC / DC conversion modules 71, whose input terminals are respectively connected to the two secondary sides of the second transformer 6.
[0046] The DC feeder cabinet 230 is equipped with a three-in-two switch assembly for electrical interlocking. The three-in-two switch assembly includes a first output switch QF1 and a second output switch QF2 located at the output terminals of the two bidirectional AC / DC conversion modules 71, and a tie switch QF3 connected in parallel between the first output switch QF1 and the second output switch QF2. The parallel connection or isolation of the two AC / DC conversion paths can be achieved by controlling the on / off state of the tie switch QF3.
[0047] Preferably, the system operates based on real-time collected multi-dimensional feedback signals, including but not limited to AC side voltage, current, frequency, and phase; DC side voltage and current; and switch status, which are comprehensively analyzed by the central control unit. The central control unit continuously monitors the shore-side power grid status, the vessel 300's connection status, the energy storage unit 310's state of charge, and the preset operating plan. When specific conditions are met, such as the vessel 300 being docked and effectively connected, the shore power grid being in good condition, the state of charge (SOC) being higher than the discharge threshold, or the power grid being in peak hours, the system determines to enter discharge mode. When charging the vessel 300 is required, such as when the SOC is lower than the threshold, during a power grid off-peak period, or when the vessel 300 is about to depart, the system enters charging mode. The mode switching process involves timing control and state interlocking. For example, when switching from charging to discharging: First, the bidirectional AC / DC converter module 71 needs to smoothly stop the rectification operation, disconnect the DC side output contactor in the DC feeder cabinet 230, then configure the IGBT drive signal to inverter mode, and start the grid-connected synchronization control to adjust the amplitude, frequency and phase of the inverter output voltage to synchronize it with the AC distribution module 2 bus. After confirming that the synchronization is correct and there are no protection alarms, close the AC side grid-connected contactor to gradually increase the inverter power output.
[0048] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A bidirectional charging and discharging system for ship-shore applications, characterized in that, The system includes a high-voltage input module (1), which is connected to a shore power source and transmits the high-voltage input signal to an AC power distribution module (2). The AC power distribution module (2) is connected to a low-voltage power distribution module (4) via a first transformer (3) and to a shore power pile (5) to supply power to the ship (300). The AC power distribution module (2) is further connected to an AC / DC conversion module (7) via a second transformer (6). The AC / DC conversion module (7) is connected to the ship (300) via a cable device (9). The AC / DC conversion module (7) includes a bidirectional AC / DC conversion module (71). When the ship (300) needs to be charged, the bidirectional AC / DC conversion module (71) rectifies the AC power into DC power and outputs it to the energy storage unit (310) of the ship (300) through the cable device (9). When the ship (300) needs to be discharged, the bidirectional AC / DC conversion module (71) inverts the DC power of the energy storage unit (310) into AC power and feeds it back to the shore power grid through the AC power distribution module (2).
2. The ship-shore bidirectional charging and discharging system as described in claim 1, characterized in that, The shore-based facility is equipped with an AC prefabricated module (100) and a DC prefabricated module (200); among them, The AC prefabricated compartment (100) is equipped with a main feeder cabinet (110), a high-voltage incoming cabinet (120), a metering cabinet (130), a first feeder cabinet (140), a second feeder cabinet (150), a first transformer cabinet (160), a low-voltage incoming cabinet (170), and a low-voltage incoming and outgoing cabinet (180). The main feeder cabinet (110) and the high-voltage incoming cabinet (120) form the high-voltage input module (1). The metering cabinet (130), the first feeder cabinet (140), and the second feeder cabinet (150) form the AC power distribution module (2). The first transformer cabinet (160) is equipped with the first transformer (3). The low-voltage incoming cabinet (170) and the low-voltage incoming and outgoing cabinet (180) form the low-voltage power distribution module (4). The DC prefabrication compartment (200) is equipped with a second transformer cabinet (210), a rectifier cabinet (220) and a DC feeder cabinet (230). The second transformer cabinet (210) is equipped with a second transformer (6). The rectifier cabinet (220) is equipped with the AC-DC conversion module (7). The DC feeder cabinet (230) is equipped with a DC power supply module (8) and is connected to the cable equipment (9).
3. The ship-shore bidirectional charging and discharging system as described in claim 2, characterized in that, The bidirectional AC / DC conversion module (71) includes a converter unit (71a), a filter unit (71b), and a control unit (71c). The control unit (71c) controls the converter unit (71a) to achieve bidirectional flow between AC and DC through space vector modulation technology.
4. The ship-shore bidirectional charging and discharging system as described in claim 2, characterized in that, The first transformer (3) is a three-phase isolation transformer. The primary side of the three-phase isolation transformer is connected to the first feeder cabinet (140), and the two secondary sides are respectively connected to the low-voltage incoming cabinet (170) and the low-voltage incoming and outgoing cabinet (180). The low-voltage incoming cabinet (170) is also connected to the UPS power supply and the high-voltage cabinet heating power supply.
5. A ship-shore bidirectional charging and discharging system as described in claim 4, characterized in that, The input voltage of the high voltage input module (1) is 10kV AC. The first transformer (3) steps down the input voltage to 0.4kV and outputs it to the low voltage distribution module (4). The second transformer (6) steps down the input voltage to 0.66kV and outputs it to the AC-DC conversion module (7).
6. A ship-shore bidirectional charging and discharging system as described in claim 1, characterized in that, The cable equipment (9) includes a cable winding and unwinding drum, a cable track, and an automatic plugging and unplugging device, used to achieve rapid connection of cables between shore and ship.
7. A ship-shore bidirectional charging and discharging system as described in claim 1, characterized in that, The low-voltage power distribution module (4) is connected to three shore power piles (5) and is equipped with a spare interface.
8. A ship-shore bidirectional charging and discharging system as described in any one of claims 2-5, characterized in that, The second transformer (6) is a three-phase isolation transformer, and its primary side is connected to the AC power distribution module (2). The rectifier cabinet (220) is equipped with two bidirectional AC / DC conversion modules (71), and their input terminals are respectively connected to the two secondary sides of the second transformer (6).
9. A ship-shore bidirectional charging and discharging system as described in claim 8, characterized in that, The DC feeder cabinet (230) is equipped with a three-in-two switch assembly for electrical interlocking. The three-in-two switch assembly includes a first output switch (QF1) and a second output switch (QF2) located at the output terminals of the two bidirectional AC / DC conversion modules (71), and a tie switch (QF3) connected in parallel between the first output switch (QF1) and the second output switch (QF2). The parallel connection or isolation of the two AC / DC conversion paths is realized by controlling the on / off state of the tie switch (QF3).