A ship battery cluster independent power-on and power-off control system

Abstract

The utility model discloses a kind of ship battery cluster independent power-on and power-off control system, including ac distribution board, battery inverter unit and power supply battery cluster;And battery inverter unit includes AFE active front end module and several bidirectional DC / DC converters;The two ends of AFE active front end module are connected with alternating current bus and direct current bus respectively;Each power supply battery cluster is independently connected to the low voltage side of a bidirectional DC-DC converter;The high voltage side of each bidirectional DC-DC converter is connected and forms common node, and common node is connected to direct current bus by second switch;The low voltage side of bidirectional DC / DC converter is connected with corresponding power supply battery cluster;BMS battery control system is connected with the enable end of bidirectional DC / DC converter and power supply battery cluster;BAU stack level control unit is communicatively connected with the BMS battery control system.Solve the defects existing in the whole stack coordination control, single cluster independent power-on and power-off, fault isolation and ship special working condition adaptation of existing system.

Description

Technical Field

[0001] This utility model relates to the field of marine electric technology, and in particular to an independent power-on and power-off control system for marine battery clusters. Background Technology

[0002] With the rapid advancement of green shipping and ship electrification, high-capacity, high-voltage lithium battery systems have become the mainstream power configuration for inland waterway, coastal, and special-purpose vessels. To meet the requirements of megawatt-level power and high reliability, modern marine battery systems generally adopt a three-level architecture: BMU (Battery Module Management Unit) → BCU (Battery Cluster Control Unit) → BAU (Built-up Unit), achieving hierarchical management of "individual cell acquisition—cluster-level control—whole-pile coordination." This architecture forms a battery stack by connecting multiple clusters in parallel, which is then connected to the DC bus and propulsion converter, improving capacity, redundancy, and maintainability, and adapting to the long-duration, high-power, and high-safety operation requirements of ships.

[0003] While the current three-tier architecture solves the problem of large-scale management, it still has significant shortcomings in overall cluster coordination control, independent power-on / off of individual clusters, fault isolation, and adaptation to special ship operating conditions, directly affecting system safety, efficiency, and lifespan. Existing technologies have the following deficiencies: (1) Poor inter-cluster consistency, prominent barrel effect in overall pile circulation and lifetime; (2) The power-on and power-off of a single cluster depends on manual / centralized commands, and lacks autonomous and smooth switching capabilities; (3) The overall power distribution is coarse, and the dynamic response is not well adapted to the operating conditions; (4) The lack of clear fault isolation and safety control levels can easily lead to a chain of failures. Summary of the Invention

[0004] This invention provides an independent power-on / off control system for ship battery clusters to overcome the aforementioned technical problems.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows: An independent power supply and deactivation control system for a ship battery cluster includes an AC power distribution board, a battery inverter unit, a power supply battery cluster, and a battery control system; and the battery inverter unit includes an active front-end module and several bidirectional DC / DC converters. One end of the active front-end module is connected to the AC bus in the AC distribution board; the other end of the active front-end module is connected to the DC bus through a first switch. Each of the power supply battery clusters is independently connected to the low-voltage side of a bidirectional DC-DC converter; the high-voltage sides of each of the bidirectional DC-DC converters are connected to form a common node, which is connected to the DC bus via a second switch; and the low-voltage side of each bidirectional DC / DC converter is connected to the corresponding power supply battery cluster; the battery control system is connected to the enable terminal of the bidirectional DC / DC converter and the power supply battery cluster respectively. The stack-level control unit is communicatively connected to the battery control system; the stack-level control unit is used to send the bidirectional DC / DC converter closing or opening commands to the battery control system. The battery control system is used to receive a disconnect command to control the bidirectional DC / DC converter to disconnect, thereby achieving power-off maintenance of the corresponding connected power supply battery cluster; or to receive a close command to control the bidirectional DC / DC converter to close, thereby achieving power-on operation of the corresponding connected power supply battery cluster, and to monitor the voltage of the power supply battery cluster and the bus voltage of the DC bus in real time. The battery control system is used to pre-charge the power supply battery cluster by using a bidirectional DC / DC converter as a boost converter when the voltage of the corresponding connected power supply battery cluster is less than the bus voltage of the DC bus; or to pre-discharge the power supply battery cluster by using a bidirectional DC / DC converter as a buck converter when the voltage of the corresponding connected power supply battery cluster is greater than the bus voltage of the DC bus.

[0006] Furthermore, a transformer is provided between the active front-end module and the AC bus in the AC distribution board; one end of the transformer is connected to the AC bus via a third switch; the other end of the transformer is electrically connected to the AFE active front-end module.

[0007] Furthermore, the first switch, the second switch, and the third switch are all electrically controlled switches.

[0008] Furthermore, the battery control system includes a battery cluster control unit and a battery module management unit configured for the power supply battery cluster; the battery cluster control unit is connected to the battery module management unit and the stack-level control unit respectively; the battery module management unit is used to monitor the voltage of the power supply battery cluster; the stack-level control unit is used to monitor the bus voltage of the DC bus; the battery cluster control unit is used to generate an early warning signal and feed it back to the battery control system when it detects overvoltage, overcurrent, overheating or insulation fault in the corresponding power supply battery cluster; the battery control system is used to receive the early warning signal and control the corresponding bidirectional DC / DC converter to disconnect to cut off the connection between the power supply battery cluster and the DC bus.

[0009] Furthermore, each of the power supply battery clusters is composed of several battery modules connected in series or in parallel.

[0010] Furthermore, each bidirectional DC / DC converter adopts either an isolated DC / DC converter or a non-isolated DC / DC converter.

[0011] Beneficial Effects: This invention provides an independent power-on / off control system for ship battery clusters. By introducing a battery inverter unit, it enables individual battery clusters to be powered on and off autonomously and smoothly, ensuring the continuity of ship navigation and improving system operational safety. This invention also achieves cluster-level autonomous decision-making capability through the battery cluster control unit. Specifically, when a single battery cluster experiences faults such as overvoltage, overcurrent, overheating, or insulation failure, it can autonomously disconnect within milliseconds without requiring stack-level commands, preventing the fault from spreading to the entire stack. Simultaneously, it coordinates with other battery clusters to autonomously maintain power supply. Under extreme fault conditions, it can achieve cluster-level electrical isolation, effectively preventing stack-wide failure and significantly improving system reliability and safety redundancy. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the independent power-on / off control system for the ship battery cluster of this utility model.

[0014] In the diagram: 1. AC distribution board; 2. Transformer; 3. Active front-end module; 4. DC bus; 5. Stack-level control unit; 6. First DC / DC converter; 7. Second DC / DC converter; 8. Third DC / DC converter; 9. First power supply battery cluster; 10. Second power supply battery cluster; 11. Third power supply battery cluster; 12. Cluster-level control unit; 13. Module-level acquisition unit. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0016] This embodiment provides an independent power-on / off control system for ship battery clusters, such as... Figure 1As shown, the system includes an AC distribution board, a battery inverter unit, a power supply battery pack, and a battery management system (BMS). The battery inverter unit includes an active front-end module (AFE) and several bidirectional DC / DC converters (Direct Current to Direct Current Converters). In this embodiment, the active front-end module (AFE) has two operating modes: rectification mode, which converts AC power from the grid into DC power to charge the DC bus and battery pack; and inverter mode, which converts DC power from the battery pack or DC bus into AC power to feed back to the grid or supply the ship's propulsion motor.

[0017] One end of the active front-end module (AFE) is connected to the AC bus in the AC distribution board; the other end of the active front-end module (AFE) is connected to the DC bus through the first switch. Each of the power supply battery clusters is independently connected to the low-voltage side of one of the bidirectional DC / DC converters; the high-voltage sides of each of the bidirectional DC / DC converters are connected to form a common node, and the common node is connected to the DC bus through a second switch; and the low-voltage side of each bidirectional DC / DC converter is connected to the corresponding power supply battery cluster; the battery control system, i.e., BMS, is connected to the enable terminal of the bidirectional DC / DC converter and the power supply battery cluster respectively. The stack-level control unit (BAU) is communicatively connected to the battery control system (BMS); the stack-level control unit (BAU) is used to issue opening or closing commands of the bidirectional DC / DC converter to the battery control system (BMS). The battery control system (BMS) is used to receive disconnect commands to control the bidirectional DC / DC converter to disconnect, thereby enabling the power-off maintenance of the corresponding connected battery pack; or to receive close commands to control the bidirectional DC / DC converter to close, thereby enabling the power-on operation of the corresponding connected battery pack, and to monitor the voltage of the battery pack and the DC bus voltage in real time. The battery control system (BMS) is used to pre-charge the power supply battery cluster by using a bidirectional DC / DC converter as a boost converter when the voltage of the corresponding connected power supply battery cluster is less than the bus voltage of the DC bus; or to pre-discharge the power supply battery cluster by using a bidirectional DC / DC converter as a buck converter when the voltage of the corresponding connected power supply battery cluster is greater than the bus voltage of the DC bus.

[0018] In a specific embodiment, a transformer is provided between the active front-end module (AFE) and the AC bus in the AC distribution board; one end of the transformer is connected to the AC bus via a third switch; the other end of the transformer is electrically connected to the active front-end module (AFE).

[0019] In a specific embodiment, the first switch, the second switch, and the third switch are electrically controlled switches, such as electrically controlled contactors or relays.

[0020] In a specific embodiment, the battery control system (BMS) includes a battery cluster control unit (BCU) and a battery module management unit (BMU) configured for the power supply battery clusters. The BCU is connected to both the BMU and the stack-level control unit (BAU). The BMU monitors the voltage of the power supply battery clusters, while the BAU monitors the bus voltage of the DC bus. When the BCU detects overvoltage, overcurrent, overheating, or insulation faults in the corresponding power supply battery cluster, it generates an early warning signal and feeds it back to the BMS. The BMS receives the early warning signal and controls the corresponding bidirectional DC / DC converter to disconnect the power supply battery cluster from the DC bus. Specifically, in this embodiment, the BCU is connected to each battery module within the power supply battery cluster via a sampling harness to collect data such as individual cell voltage, total voltage, current, and temperature. The battery cluster control unit (BCU) communicates with the corresponding bidirectional DC / DC converter via a CAN bus to control its start / stop and operating mode. Furthermore, when the BCU detects an overvoltage, overcurrent, or overheating fault in its battery cluster, it immediately and autonomously disconnects the main contactor and reports the fault status to the stack-level control unit (BAU) via the CAN bus. The BAU, based on empirical values, reallocates total power to the remaining healthy battery clusters according to their available capacity, ensuring continued system operation.

[0021] In a specific embodiment, each of the power supply battery clusters is composed of several battery modules connected in series or in parallel.

[0022] In specific embodiments, each bidirectional DC / DC converter is either an isolated DC / DC converter or a non-isolated DC / DC converter.

[0023] In this embodiment, the bidirectional DC-DC converter can achieve electrical isolation and independent control. Each power supply battery cluster is independently connected to a bidirectional DC / DC converter, and the output of each bidirectional DC / DC converter is then connected in parallel to a common DC bus. This can achieve: (1) inter-cluster electrical isolation: there is no direct electrical connection between each power supply battery cluster, which completely eliminates the circulating current loss caused by the voltage difference between clusters when directly connected in parallel in the traditional way; (2) independent power-on and power-off: by controlling the enable signal of each bidirectional DC / DC converter, any battery cluster can be started or shut down independently without shutting down the entire cluster; for example, it is possible to completely de-energize the power supply battery cluster 3 for maintenance while the power supply battery cluster 1 and the power supply battery cluster 2 are working.

[0024] In this embodiment, the bidirectional DC / DC converter can also act as a "smart gateway" for voltage matching and buffering: Since the SOC (state of charge) and voltage of each power supply battery cluster may differ, direct parallel connection will generate a huge inrush current. The bidirectional DC / DC converter solves this problem: (1) Power-on pre-synchronization: Before the power supply battery cluster is connected to the grid, the bidirectional DC / DC converter starts first and adjusts its output voltage to slowly approach the DC bus voltage until the voltage difference is within the preset safe range. At this time, closing the contactor will result in almost no inrush current. (2) Power-off voltage equalization: When the power supply battery cluster is disconnected from the grid, the bidirectional DC / DC converter can control the smooth transfer of energy, so that the voltage at the battery cluster terminal drops slowly to close to the bus voltage, avoiding arcing and voltage drop.

[0025] In addition, the bidirectional DC / DC converter in this embodiment can also achieve refined power allocation based on SOC based on empirical values. The system no longer distributes power evenly, but achieves "intelligent allocation" through the bidirectional DC / DC converter: (1) During discharge: the power supply battery cluster with high SOC can be allocated more discharge power; the power supply battery cluster with low SOC is allocated less discharge power. In this way, the power supply battery cluster with high charge outputs more and its charge drops faster, while the power supply battery cluster with low charge gets a rest, and the SOC of each power supply battery cluster gradually converges. (2) During charging: the power supply battery cluster with low SOC is allocated more charging power; the power supply battery cluster with high SOC is allocated less charging power or even stops charging, avoiding overcharging of the power supply battery cluster with high charge, and replenishing the power supply battery cluster with low charge faster. This refined power allocation method based on SOC can fundamentally solve the "barrel effect" - no longer be limited by the worst-performing cluster in terms of overall capacity.

[0026] The bidirectional DC / DC converter in this embodiment can also provide fault isolation and redundancy fault tolerance. When a power supply battery cluster or its corresponding bidirectional DC / DC converter fails: (1) Millisecond-level autonomous disconnection: The BCU can immediately control the DC / DC converter to stop working and disconnect the corresponding contactor to disconnect the faulty unit from the system; (2) The remaining units continue to operate: Other healthy power supply battery clusters and bidirectional DC / DC converters continue to work normally. The system only loses part of its power and will not be completely paralyzed, which is crucial for the continuity of ship navigation.

[0027] This embodiment also includes the following specific application examples: Assume the system has three power supply battery clusters 1, 2, and 3. Power supply battery cluster 2 needs maintenance. Using three bidirectional DC / DC converters, click "Disable Power Supply Battery Cluster 2" on the preset control panel. The system automatically controls the corresponding bidirectional DC / DC converter, DC / DC-2, to stop working and disconnect its internal contactor. Power supply battery cluster 2 is now completely isolated from the system, while other parts continue operating. Then, perform maintenance on the isolated power supply battery cluster 2. After maintenance, click "Enable Power Supply Battery Cluster 2" on the panel, and the system automatically reintegrates it. Specific scenarios include the following: Scenario 1: When a battery cluster is powered off for maintenance, its voltage may differ from other continuously operating battery clusters. Forcibly powering it back on could cause a dangerous instantaneous circulating current surge. Operating steps: Step 1: The battery control system (BMS) performs self-tests and judgments. When an operator requests to bring the maintained battery cluster (let's say power supply battery cluster 2) back online, the BMS battery control system will first read the voltage (V_string2), temperature, insulation resistance, and other status information of power supply battery cluster 2; the battery control system, i.e., the BMS, will also read the DC bus voltage (V_dc_bus) and the overall status of other online battery clusters; the battery control system, i.e., the BMS, will compare the difference between the voltage of power supply battery cluster 2 and the DC bus voltage; Step 2: Use the bidirectional DC / DC converter as a "smart buffer" for voltage synchronization. The battery management system (BMS) itself cannot change the voltage, but it can achieve this by controlling the bidirectional DC / DC converter. Scenario A: When the voltage of power supply battery cluster 2 is less than the bus voltage, the battery control system (BMS) will command the corresponding bidirectional DC / DC converter of power supply battery cluster 2 to start a pre-charging process: that is, at this time, the corresponding bidirectional DC / DC converter will act as a boost converter, very slowly and controllably raising the output voltage from the voltage of power supply battery cluster 2 to a level close to the bus voltage; at this time, the battery control system (BMS) monitors the voltage of the two in real time, and when the voltage difference is reduced to a safe threshold (e.g., within 10V), the pre-synchronization is confirmed to be completed.

[0028] Scenario B: When the voltage of battery cluster 2 exceeds the bus voltage, the battery control system (BMS) will instruct the bidirectional DC / DC converter to initiate a pre-discharge process. This involves the bidirectional DC / DC converter acting as a step-down converter, controllably transferring the high-voltage energy from battery cluster 2 to the bus (or supplying power to other loads or being absorbed by other bidirectional DC / DC converters), thus slowly reducing the voltage at battery cluster 2 to near the bus voltage. Similarly, the BMS monitors this in real-time until the voltage difference reaches a safe range. The key difference lies in the controlled and gradual energy transfer through the power devices and inductors of the bidirectional DC / DC converter, rather than generating a large instantaneous surge current as in direct parallel connection. Here, the bidirectional DC / DC converter acts as a "buffer" or "synchronizer."

[0029] Step 3: Grid-connected operation: After the battery control system (BMS) confirms that the voltage difference between the output voltage of the bidirectional DC / DC converter of battery cluster 2 and the DC bus voltage is within a safe range, the BMS issues a "permit to close" command. The bidirectional DC / DC converter of battery cluster 2 will close the grid-connected contactor at its output terminal (or achieve seamless switching via a semiconductor switch). Since the voltages on both sides are basically the same at this time, there is almost no inrush current when closing. After the contactor closes, the BMS commands the bidirectional DC / DC converter to enter the normal bidirectional charging and discharging mode, receiving commands according to the total power demand and starting to contribute or absorb power. This power-on process is not a simple closing, but a refined "automatic pre-synchronization" process jointly executed by the BMS and the bidirectional DC / DC converter—the "pre-synchronization" and "soft-start" functions of the bidirectional DC / DC converter.

[0030] Scenario 2: Currently, the SOC and voltage of the battery are related. Even if the voltage is made consistent at the moment of grid connection through the bidirectional DC / DC converter, there will still be problems in long-term operation if the state of charge of each power supply battery cluster is very different. In this embodiment, the power allocation based on SOC is no longer evenly distributed, but is "intelligently allocated" through the bidirectional DC / DC converter: the total power (P_total) that the entire battery system needs to release or absorb is calculated by the preset upper-level controller (such as EMS) or battery control system, i.e., BMS; the SOC value of each power supply battery cluster is obtained in real time through the BMS battery control system, and the system dynamically adjusts the power command allocated to each bidirectional DC / DC converter based on the SOC of each power supply battery cluster and empirical values: (1) During discharge: the power supply battery cluster with high SOC is allocated more discharge power; the power supply battery cluster with low SOC is allocated less discharge power. In this way, the high-capacity battery clusters will discharge faster, while the low-capacity battery clusters will "rest," thus allowing the SOC of each battery cluster to gradually converge; (2) During charging: the low-capacity battery clusters are allocated more charging power; the high-capacity battery clusters are allocated less charging power or even stop charging. In this way, the low-capacity battery clusters will be recharged faster, avoiding overcharging of the high-capacity clusters. For example: Total discharge demand: 300kW Battery cluster 1 SOC = 80% Battery cluster 2 SOC = 60% Battery cluster 3, SOC = 40% The power distribution result may be: power supply battery cluster 1 discharges 150kW, power supply battery cluster 2 discharges 100kW, and power supply battery cluster 3 discharges 50kW.

[0031] Effect: Battery cluster 1, with the highest power output, experiences the fastest power loss; battery cluster 3, with the lowest power output, experiences the slowest power loss. After several cycles, the State of Charge (SOC) of the three battery clusters will converge. Fine-grained power control is achieved through a bidirectional DC / DC converter, actively adjusting the charging and discharging energy of each battery cluster, thereby aligning the SOC of the three battery clusters to achieve "energy balance."

[0032] Compared with the prior art, the system described in this embodiment has the following advantages: 1. Effectively improves inter-cluster consistency, reduces circulating current loss, overcomes the bottleneck effect in overall stack lifespan, and enhances system endurance and lifespan. The system described in this embodiment, through a cluster-level independent adjustment mechanism, can dynamically adjust the charging and discharging power, power-on / off sequence, and balancing strategy of a single cluster based on the real-time differences in SOC, voltage, internal resistance, and temperature of each cluster. This effectively suppresses irreversible DC circulating current caused by inter-cluster voltage differences, reducing ineffective energy consumption by 5%–10%. Simultaneously, it enables single-cluster rotation and balanced charging and discharging, breaking the bottleneck of "worst cluster limiting overall stack capacity," increasing the usable capacity of the entire stack by more than 10%, slowing down the overall battery aging rate, and adapting to the long-duration, high-capacity operation requirements of ships.

[0033] 2. The system enables autonomous and smooth power-on / off switching of individual clusters, ensuring continuous ship navigation and enhancing system operational safety. This embodiment features independent pre-charging, voltage equalization, load transfer, and timing control modules for each cluster, avoiding issues such as power-on surge impacts, contactor welding, power-off arcing, and sudden bus voltage drops. It supports independent switching of individual clusters, eliminating the need for a complete cluster shutdown during maintenance, faults, or capacity expansion, ensuring uninterrupted ship navigation. Furthermore, a cluster-relay collaborative interlocking mechanism is added to prevent accidental closing, cross-cluster short circuits, and other safety hazards, improving operational and running safety.

[0034] 3. Optimize dynamic power allocation across the entire reactor to improve system response speed and adaptability to operating conditions, ensuring stable overall reactor output. The system described in this embodiment abandons traditional fixed-ratio or average allocation strategies. The reactor-level controller can dynamically schedule the output of each cluster based on the real-time health status (SOH) of each cluster, allowable charge / discharge power, and ship load fluctuations, avoiding overcurrent in strong clusters and underload in weak clusters. It also shortens data acquisition and communication delays, achieving millisecond-level synchronization of reactor-cluster commands, adapting to severe load fluctuations under conditions such as wind and waves, meeting classification society requirements for redundant power supply and dynamic response, and ensuring stable and efficient overall reactor output.

[0035] 4. Clearly define fault isolation levels to improve fault response speed and eliminate the risk of cascading failures across the entire stack. The system described in this embodiment endows the BCU with cluster-level autonomous decision-making capabilities. When a single cluster experiences faults such as overvoltage, overcurrent, overheating, or insulation failure, it can achieve millisecond-level autonomous disconnection without requiring stack-level commands, thus preventing the fault from spreading to the entire stack. Simultaneously, it coordinates with healthy clusters to autonomously maintain power supply. Under extreme fault conditions, it can achieve cluster-level electrical isolation, effectively preventing the entire stack from collapsing and significantly improving system reliability and safety redundancy.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A ship battery cluster independent power-on / off control system, characterized in that, It includes an AC power distribution board, a battery inverter unit, a power supply battery cluster, and a battery control system; and the battery inverter unit includes an active front-end module and several bidirectional DC / DC converters. One end of the active front-end module is connected to the AC bus in the AC distribution board; the other end of the active front-end module is connected to the DC bus through a first switch. Each of the power supply battery clusters is independently connected to the low-voltage side of a bidirectional DC-DC converter; the high-voltage sides of each of the bidirectional DC-DC converters are connected to form a common node, which is connected to the DC bus via a second switch; and the low-voltage side of each bidirectional DC / DC converter is connected to the corresponding power supply battery cluster; the battery control system is connected to the enable terminal of the bidirectional DC / DC converter and the power supply battery cluster respectively. The stack-level control unit is communicatively connected to the battery control system; the stack-level control unit is used to send the bidirectional DC / DC converter closing or opening command to the battery control system. The battery control system is used to receive disconnection commands to control the bidirectional DC / DC converter to disconnect, thereby achieving power-off maintenance of the corresponding connected battery pack. Alternatively, it can be used to receive closing commands to control the closing of bidirectional DC / DC converters to enable the power supply of the corresponding connected battery packs, and to monitor the voltage of the battery packs and the bus voltage of the DC bus in real time. The battery control system is used to pre-charge the power supply battery cluster by using a bidirectional DC / DC converter as a boost converter when the voltage of the corresponding connected power supply battery cluster is less than the bus voltage of the DC bus; or to pre-discharge the power supply battery cluster by using a bidirectional DC / DC converter as a buck converter when the voltage of the corresponding connected power supply battery cluster is greater than the bus voltage of the DC bus.

2. The independent power-on / off control system for a ship battery cluster according to claim 1, characterized in that, A transformer is provided between the active front-end module and the AC bus in the AC distribution board; One end of the transformer is connected to the AC bus via a third switch; the other end of the transformer is electrically connected to the active front-end module.

3. The independent power-on / off control system for a ship battery cluster according to claim 2, characterized in that, The first switch, the second switch, and the third switch are all electrically controlled switches.

4. The independent power-on / off control system for a ship battery cluster according to claim 3, characterized in that, The battery control system includes a battery cluster control unit and a battery module management unit configured for powering the battery clusters; the battery cluster control unit is connected to both the battery module management unit and the stack-level control unit; the battery module management unit is used to monitor the voltage of the powering battery clusters; the stack-level control unit is used to monitor the bus voltage of the DC bus; the battery cluster control unit is used to generate an early warning signal and feed it back to the battery control system when it detects overvoltage, overcurrent, overheating, or insulation faults in the corresponding powering battery clusters; the battery control system is used to receive the early warning signal and control the corresponding bidirectional DC / DC converter to disconnect the powering battery cluster from the DC bus.

5. The independent power-on / off control system for a ship battery cluster according to claim 4, characterized in that, Each of the aforementioned power supply battery clusters is composed of several battery modules connected in series or in parallel.

6. The independent power-on / off control system for a ship battery cluster according to claim 5, characterized in that, Each bidirectional DC / DC converter uses either an isolated DC / DC converter or a non-isolated DC / DC converter.

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