A high-voltage alternating current charging range extender electric boat power system and control method

Abstract

The application belongs to the technical field of ship power systems, and particularly relates to a high-voltage alternating current charging range extender electric ship power system and a control method. The system comprises a lithium battery module, a direct current distribution module, an alternating current distribution module, a high-voltage alternating current charging module, a low-voltage shore power box, a propulsion module, a daily load and an EMS system. The application provides a high-voltage alternating current charging range extender electric ship power system and a control method, realizes multi-mode charging, reduces the cost of equipment and wharf construction, can adapt to high-voltage shore power and low-voltage shore power, has high system integration and efficient control.

Description

Technical Field

[0001] This invention belongs to the field of marine power system technology, specifically relating to a power system and control method for a high-voltage AC charging range-extended electric ship. Background Technology

[0002] Traditional ships mostly use fuel-powered systems, which suffer from high energy consumption and large pollutant emissions, failing to meet the development trend of green shipping. Existing electric ship power systems mostly use a single charging method, which has poor adaptability and is difficult to meet the power supply conditions of different docks; some DC charging solutions require large and numerous cables, making manual operation difficult, and docks need to build supporting charging stations, shore power winches, and other equipment, resulting in high construction costs; at the same time, some electric ships are prone to battery depletion in emergency scenarios such as prolonged typhoons and being far from docks, resulting in insufficient reliability of ship operation.

[0003] Furthermore, the energy management, propulsion control, and monitoring and alarm functions of existing ship electrical systems are independent, resulting in slow system response and weak fault handling capabilities, failing to simultaneously ensure the ship's dynamic response performance and operational safety. Currently, most electric ships use direct DC power, with charging piles at the dock and shore power winches or charging arms pulling the shore-based DC power to the ship's receiving equipment. When the power is high, the cables are thick, requiring electric devices to transport the cables to the shore, making manual operation impossible. Alternatively, a hybrid mode is used, where the ship has lithium batteries and several diesel generator sets. These generator sets are directly connected to the DC busbar via rectifiers, directly participating in the ship's propulsion system. Another option is to use only AC 400V shore power to charge the ship's batteries. This method is only suitable for ships with small-capacity battery systems. When the battery capacity reaches a certain level, the AC 400V shore power capacity is limited, and the required number of thick cables makes it difficult to operate in practice. Summary of the Invention

[0004] To address the problems of existing electric boat power systems, such as limited charging methods, poor shore power compatibility, high dock construction costs, and low system integration and control efficiency, this invention provides a power system and control method for a high-voltage AC charging range-extended electric boat. This system enables multi-mode charging, reduces equipment and dock construction costs, is compatible with both high-voltage and low-voltage shore power, and features high system integration and efficient control.

[0005] The technical solution of the present invention is as follows: A power system for a high-voltage AC charging range-extended electric boat includes a lithium battery module, a DC power distribution module, an AC power distribution module, a high-voltage AC charging module, a low-voltage shore power box, a propulsion module, daily loads, and an EMS system. The lithium battery module includes several lithium battery packs and is connected to the DC bus of the DC power distribution module via corresponding battery converters. The DC power distribution module includes a DC power distribution board and a DC bus tie solid-state switch. The DC bus of the DC power distribution board is divided into a first DC bus and a second DC bus. The first DC bus and the second DC bus are connected by the DC bus tie solid-state switch. Under normal operating conditions, when the DC bus tie solid-state switch is closed, the first DC bus and the second DC bus are connected in parallel to supply power. The high-voltage AC charging module includes an AC high-voltage socket box, a high-voltage AC connection panel, a high-voltage AC transformer, and two sets of shore power rectifiers. It can step down the shore power supply, rectify it through the rectifiers, and then connect it to the DC bus. It charges the lithium battery pack through the battery converter. In the charging mode, the DC bus tie solid-state switch is turned on to disconnect the first DC bus and the second DC bus. The AC power distribution module includes a first AC power distribution board and a second AC power distribution board connected to the first AC power distribution board. The busbars of the first AC power distribution board are divided into a first AC busbar and a second AC busbar. The first AC busbar and the second AC busbar are connected via an AC bus tie switch. The first AC power distribution board is connected to the DC power distribution module through an inverter and a transformer. The AC power distribution module is connected to the power input terminal of the household load. The output terminal of the low-voltage shore power box is connected to the first AC power distribution board of the AC power distribution module. It can be reverse rectified to the DC power distribution module through the transformer and inverter of the AC power distribution module. The DC power distribution module is connected to the lithium battery pack through the battery converter. The low-voltage AC shore power output by the low-voltage shore power box can charge the lithium battery pack. The propulsion module includes at least two propulsion motors with adjustable frequency or power. The propulsion motors are connected to the DC busbar through a propulsion inverter, which converts DC power into AC power to drive the propulsion motors. The control terminal of the EMS system is connected to the control terminals of all switching devices, power conversion devices, power devices, and monitoring sensors in the system.

[0006] Furthermore, the two shore power rectifiers in the high-voltage AC charging module include a first shore power rectifier and a second shore power rectifier. The connection relationship between the high-voltage AC charging module and the DC power distribution module is as follows: the input terminal of the AC high-voltage socket box is connected to the shore AC 6000V high-voltage AC shore power; the output terminal of the AC high-voltage socket box is connected to the AC high-voltage connection panel via a circuit breaker; the output terminal of the high-voltage AC connection panel is connected to the input terminal of the high-voltage AC transformer via a circuit breaker; the step-down output terminal of the high-voltage AC transformer is connected to the AC input terminal of the first shore rectifier and the AC input terminal of the second shore rectifier via wires; the DC output terminal of the first shore rectifier is connected to the first DC busbar via a fuse; and the DC output terminal of the second shore rectifier is connected to the second DC busbar via a fuse.

[0007] Furthermore, the transformer of the AC power distribution module includes a first daily-use transformer and a second daily-use transformer; the inverter of the AC power distribution module includes a first daily-use inverter and a second daily-use inverter. The specific connection relationship between the AC power distribution module and the DC power distribution module is as follows: The output terminal of the shore AC400V low-voltage AC shore power is connected to the input terminal of the low-voltage shore power box via a wire. The output terminal of the low-voltage shore power box is connected to the first AC busbar and the second AC busbar via a circuit breaker. The first AC busbar is connected to one end of the first daily transformer via a circuit breaker. The other end of the first daily transformer is connected to one end of the first daily inverter via a wire. The other end of the first daily inverter is connected to the first DC busbar via a fuse. The output terminals of the second AC busbar are connected to one end of the second daily transformer via circuit breakers. The other end of the second daily transformer is connected to one end of the second daily inverter via wires. The other end of the second daily inverter is connected to the second DC busbar via fuses.

[0008] Furthermore, the lithium battery module has four lithium batteries; the connection relationship between the lithium battery module and the DC power distribution module is as follows: The first lithium battery pack is connected to one end of the first battery converter via a disconnecting switch, and the other end of the first battery converter is connected to the first DC bus via a fuse. The second lithium battery pack is connected to one end of the second battery converter via a disconnecting switch, and the other end of the second battery converter is connected to the first DC bus via a fuse. The third lithium battery pack is connected to one end of the third battery converter via a disconnecting switch, and the other end of the third battery converter is connected to the second DC bus via a fuse. The fourth lithium battery pack is connected to one end of the fourth battery converter via a disconnecting switch, and the other end of the fourth battery converter is connected to the second DC bus via a fuse.

[0009] Furthermore, the connection relationships in the first AC distribution board and the second AC distribution board are as follows: The first AC busbar is connected to one end of the first lighting transformer via a circuit breaker, and the other end of the first lighting transformer is connected to the second AC distribution board. The second AC busbar is connected to one end of the second lighting transformer via a circuit breaker, and the other end of the second lighting transformer is connected to the second AC distribution board via a wire. The first AC distribution board is connected to the input terminal of the daily load via a circuit breaker, providing AC380V AC power to the daily load; The second AC distribution board is connected to the input terminal of the external load via a circuit breaker to provide AC220V AC power to the external load.

[0010] Furthermore, the propulsion module has two propulsion motors, namely a first propulsion motor and a second propulsion motor; the connection relationship between the propulsion module and the DC power distribution module is as follows: The first DC bus is connected to the input terminal of the first propulsion inverter via a wire, and the inverter output terminal of the first propulsion inverter is connected to the input terminal of the first propulsion motor via a circuit breaker; The output terminal of the second DC busbar is connected to the input terminal of the second drive inverter via a wire; The inverter output of the second propulsion inverter is connected to the input of the second propulsion motor via a circuit breaker.

[0011] Furthermore, it also includes a backup generator set, which provides 400V AC power and is directly connected to the lithium battery pack via a pair of generator rectifiers for emergency charging. The pair of power generation rectifiers includes a first power generation rectifier and a second power generation rectifier. The DC output terminal of the first generator rectifier is connected to the charging input terminal of the first lithium battery pack and the second lithium battery pack via an electrical interlocking circuit breaker. The DC output terminal of the second generator rectifier is connected to the charging input terminals of the third and fourth lithium battery packs via an electrical interlock circuit breaker. The electrical interlocking circuit breaker includes two circuit breakers, and when the two circuit breakers are in operation, only one of them can be closed.

[0012] Furthermore, all of the lithium battery systems are equipped with a battery management system to realize battery status monitoring and management.

[0013] A power control method for a high-voltage AC charging range-extended electric boat is implemented through the aforementioned power system. The control method includes three modes: pure electric operation mode, high-voltage charging mode while moored, and low-voltage charging mode while moored; details are as follows: Pure electric operation mode: Several lithium battery groups are divided into ready-to-use lithium battery groups and standby lithium battery groups. The EMS system puts the ready-to-use lithium battery groups into operation and collects the load rate of the entire ship in real time. When the load rate reaches the preset threshold, it sends a command to close the power supply switch of the standby lithium battery group and use the standby lithium battery group. When the load rate falls below the preset threshold, the standby battery group is manually or automatically deactivated.

[0014] High-voltage charging mode while the ship is moored: When the ship is moored, the AC 6000V cable on shore is connected to the high-voltage AC socket box. After the EMS detects that the shore power signal is normal, the circuit breaker between the AC high-voltage socket box and the AC high-voltage connection panel, and the circuit breaker between the high-voltage AC connection panel and the high-voltage AC transformer are closed, and the voltage is reduced to AC 690V. At the same time, the DC bus tie solid-state switch is disconnected. After rectification by the first shore power rectifier and the second rectifier, the power is connected to the first DC bus and the second DC bus. The battery converter is started to charge the lithium battery packs connected to the first DC bus and the second DC bus respectively. The remaining battery power is monitored in real time, and the charging stops automatically when the battery is fully charged. Low-voltage charging mode while the ship is moored: When the ship is moored, the low-voltage shore power box is connected to the shore AC400V low-voltage AC shore power. The EMS system adjusts the ship's power grid to synchronize with the shore power. The AC400V low-voltage AC shore power flows into the AC distribution module and into the daily loads connected to the AC distribution module. After the EMS system completely transfers the daily loads to be powered by the AC400V low-voltage AC shore power, it stops the daily inverter. The transformer and inverter are closed and reversed to rectify the AC400V low-voltage AC shore power into DC1000V DC power, which is then connected to the first AC distribution board. The lithium battery pack is charged through the battery converter. After charging is completed, the ship's own power supply is restored first, and then the shore power is disconnected.

[0015] Furthermore, it also includes an emergency charging mode, the control method of which is as follows: Emergency charging mode: When a ship enters an emergency scenario, including a long-term typhoon resistance scenario and a scenario where it cannot dock, the EMS system will automatically start the backup generator set when the battery power is low. After the generator set output is detected to be normal, the generator rectifier will be closed, and the two lithium batteries with the lowest power will be identified first, and the constant voltage or constant current charging mode will be started. During the charging process, the uncharged lithium battery pack continues to supply power to the daily load. The EMS monitors the charging status and battery parameters in real time, and immediately stops charging and issues an alarm if any abnormality occurs.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention supports three charging methods: AC6000V high voltage AC shore power, AC400V low voltage AC shore power, and backup generator set, which are suitable for different dock power supply conditions and cover all working conditions including pure electric, berthing and emergency.

[0017] (2) The present invention adopts a high-voltage AC shore power onboard solution, which greatly reduces the specifications and quantity of cables, eliminates the need for dedicated charging stations and shore power winches, and significantly reduces the cost of terminal support.

[0018] (3) The standby generator set of the present invention adopts an independent charging circuit, which can charge the lithium battery pack in an emergency, without affecting the power supply of daily loads and avoiding battery shutdown due to power depletion.

[0019] (4) The present invention adopts a segmented design for both DC and AC busbars, and is equipped with bus tie switches and fault protection modules. In the charging mode, the DC busbar is disconnected to avoid circulating current. It has the functions of automatic fault disconnection, single-sided power supply, and tripping of non-critical loads.

[0020] (5) The EMS system of the present invention integrates energy management, propulsion control and monitoring alarm functions to realize intelligent switching of battery packs and priority scheduling of emergency charging, thereby improving energy utilization and system dynamic response speed. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the circuit logic of the present invention; In the diagram: 1-High-voltage AC socket box, 2-High-voltage AC connection panel, 3-High-voltage AC transformer, 4-First shore rectifier, 5-Second shore rectifier, 6-DC distribution board, 61-First DC busbar, 62-Second DC busbar, 63-DC bus tie solid-state switch, 7-First daily inverter, 8-Second daily inverter, 9-First daily transformer, 10-Second daily transformer, 11-First AC distribution board, 111-First AC busbar, 112-Second AC busbar, 113-AC bus tie switch, 12-Second AC distribution board, 13-Low voltage... Shore power box, 14-First lighting transformer, 15-Second lighting transformer, 16-First propulsion inverter, 17-Second propulsion inverter, 18-First propulsion motor, 19-Second propulsion motor, 20-First lithium battery pack, 21-Second lithium battery pack, 22-Third lithium battery pack, 23-Fourth lithium battery pack, 24-First battery converter, 25-Second battery converter, 26-Third battery converter, 27-Fourth battery converter, 28-Standby generator set, 29-First generator rectifier, 30-Second generator rectifier, 31-Electrical interlock circuit breaker. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0023] See Figure 1 A power system for a high-voltage AC charging range-extended electric boat includes a lithium battery module, a DC power distribution module, an AC power distribution module, a high-voltage AC charging module, a low-voltage shore power box 13, a propulsion module, daily loads, and an EMS system. The lithium battery module includes several lithium battery packs and is connected to the DC bus of the DC power distribution module via corresponding battery converters. The DC power distribution module includes a DC power distribution board 6 and a DC bus tie solid-state switch 63. The DC busbars of the DC power distribution board 6 are divided into a first DC busbar 61 and a second DC busbar 62. The first DC busbar 61 and the second DC busbar 62 are connected through the DC bus tie solid-state switch 63. Under normal operating conditions, the DC bus tie solid-state switch 63 is closed, and the first DC busbar 61 and the second DC busbar 62 are connected in parallel for power supply. The high-voltage AC charging module includes an AC high-voltage socket box 1, a high-voltage AC connection panel 2, a high-voltage AC transformer 3, and two sets of shore power rectifiers. It can step down the shore power supply and then rectify it through the rectifiers to charge the lithium battery pack through the battery converter. In the charging mode, the DC bus tie solid-state switch 63 is opened to disconnect the first DC bus 61 and the second DC bus 62. The AC power distribution module includes a first AC power distribution board 11 and a second AC power distribution board 12 connected to the first AC power distribution board 11. The busbars of the first AC power distribution board 11 are divided into a first AC busbar 111 and a second AC busbar 112. The first AC busbar 111 and the second AC busbar 112 are connected via an AC bus tie switch 113. The first AC power distribution board 11 is connected to the DC power distribution module through an inverter and a transformer. The AC power distribution module is connected to the power input terminal of the household load. The output terminal of the low-voltage shore power box 13 is connected to the first AC power distribution board 11 of the AC power distribution module. It can be rectified in reverse by the transformer and inverter of the AC power distribution module to the DC power distribution module. The DC power distribution module is connected to the lithium battery pack through the battery converter. The low-voltage AC shore power output by the low-voltage shore power box 13 can charge the lithium battery pack. The propulsion module includes at least two propulsion motors with adjustable frequency or power. The propulsion motors are connected to the DC busbar through a propulsion inverter, which converts DC power into AC power to drive the propulsion motors. The control terminal of the EMS system is connected to the control terminals of all switching devices, power conversion devices, power devices, and monitoring sensors in the system.

[0024] Example 1: Specific connection structure of the power system In this embodiment, the lithium battery module has four lithium batteries; the transformer of the AC power distribution module includes a first daily-use transformer 9 and a second daily-use transformer 10; The inverter of the AC power distribution module includes a first daily inverter 7 and a second daily inverter 8. The two shore power rectifiers in the high-voltage AC charging module include a first shore power rectifier 4 and a second shore power rectifier 5. 1. High-voltage AC charging module The input terminal of the AC high-voltage socket box 1 is connected to the shore AC 6000V high-voltage AC shore power. The output terminal of the AC high-voltage socket box 1 is connected to the AC high-voltage connection panel 2 via a circuit breaker. The output terminal of the high-voltage AC connection panel 2 is connected to the input terminal of the high-voltage AC transformer 3 via a circuit breaker. The step-down output terminal of the high-voltage AC transformer 3 is connected to the AC input terminal of the first shore rectifier 4 and the AC input terminal of the second shore rectifier 5 via wires. The DC output terminal of the first shore rectifier 4 is connected to the first DC bus 61 via a fuse. The DC output terminal of the second shore rectifier 5 is connected to the second DC bus 62 via a fuse.

[0025] 2. DC power distribution module It includes a DC distribution board 6 and a DC bus tie solid-state switch 63. The DC distribution board 6 is equipped with a first DC bus 61 and a second DC bus 62. The two DC bus sections are connected and disconnected through the DC bus tie solid-state switch 63. Under normal operating conditions, the DC bus tie solid-state switch 63 remains closed, and the two bus sections are connected in parallel to supply power to the system. The DC bus is equipped with fuses to achieve short-circuit and overload protection. The DC distribution module is only responsible for the distribution of DC power, bus switching and fault protection. All power conversion devices and load devices are connected to the DC bus. The overall operating status is controlled by the EMS system and has the functions of fault protection, status monitoring and operation information recording.

[0026] 3. Low-voltage shore power box and AC power distribution module The output terminal of the shore AC400V low-voltage AC shore power is connected to the input terminal of the low-voltage shore power box 13 via a wire. The output terminal of the low-voltage shore power box 13 is connected to the first AC busbar 111 and the second AC busbar 112 via a circuit breaker. The first AC busbar 111 is connected to one end of the first daily transformer 9 via a circuit breaker. The other end of the first daily transformer 9 is connected to one end of the first daily inverter 7 via a wire. The other end of the first daily inverter 7 is connected to the first DC busbar 61 via a fuse. The output terminal of the second AC busbar 112 is connected to one end of the second daily transformer 10 via a circuit breaker. The other end of the second daily transformer 10 is connected to one end of the second daily inverter 8 via a wire. The other end of the second daily inverter 8 is connected to the second DC busbar 62 via a fuse, thereby realizing the conversion of electrical energy between the DC and AC sides.

[0027] The first AC busbar 111 is connected to one end of the first lighting transformer 14 via a circuit breaker, and the other end of the first lighting transformer 14 is connected to the second AC distribution board 12. The second AC busbar 112 is connected to one end of the second lighting transformer 15 via a circuit breaker, and the other end of the second lighting transformer 15 is connected to the second AC distribution board 12 via a wire. The first AC distribution board 11 is connected to the input terminal of the daily load via a circuit breaker, providing AC380V AC power to the daily load; The second AC distribution board 12 is connected to the input terminal of the external load via a circuit breaker to provide AC220V AC power to the external load.

[0028] The AC400V low-voltage shore power from the low-voltage shore power box 13 is connected to the first AC distribution board 11, which can directly supply power to daily loads and external loads. It can also be reverse-rectified to DC1000V to charge the battery through the aforementioned daily transformer and daily inverter. The terms "daily load" and "external load" have the same meaning, both indicating that they can supply power to external sources. Two different names are used here to distinguish them.

[0029] 4. Lithium battery module The first lithium battery pack 20 is connected to one end of the first battery converter 24 via a disconnecting switch, and the other end of the first battery converter 24 is connected to the first DC bus 61 via a fuse. The second lithium battery pack 21 is connected to one end of the second battery converter 25 via a disconnecting switch, and the other end of the second battery converter 25 is connected to the first DC bus 61 via a fuse. The third lithium battery pack 22 is connected to one end of the third battery converter 26 via a disconnecting switch, and the other end of the third battery converter 26 is connected to the second DC bus 62 via a fuse. The fourth lithium battery pack 23 is connected to one end of the fourth battery converter 27 via a disconnecting switch, and the other end of the fourth battery converter 27 is connected to the second DC bus 62 via a fuse.

[0030] 5. Standby generator set The backup generator set 28 is powered by 400V AC power, which is directly connected to the lithium battery pack via a pair of generator rectifiers to achieve emergency charging. The pair of power generation rectifiers includes a first power generation rectifier 29 and a second power generation rectifier 30; The DC output terminal of the first power generation rectifier 29 is connected to the charging input terminal of the first lithium battery pack 20 and the second lithium battery pack 21 via an electrical interlock circuit breaker, thereby achieving that the first lithium battery pack 20 and the second lithium battery pack 21 are not charged at the same time by setting the electrical interlock circuit breaker. The DC output terminal of the second generator rectifier 30 is connected to the charging input terminals of the third lithium battery pack 22 and the fourth lithium battery pack 23 via an electrical interlock circuit breaker. By setting the electrical interlock circuit breaker, the third lithium battery pack 22 and the fourth lithium battery pack 23 are not charged at the same time. The electrical interlocking circuit breaker 31 includes two circuit breakers, and when the two circuit breakers are in operation, only one of them can be closed.

[0031] 6. Propulsion Module The propulsion module has two propulsion motors to provide power to the ship, namely the first propulsion motor 18 and the second propulsion motor 19; the connection relationship between the propulsion module and the DC power distribution module is as follows: The first DC bus 61 is connected to the input terminal of the first propulsion inverter 16 via a wire, and the inverter output terminal of the first propulsion inverter 16 is connected to the input terminal of the first propulsion motor 18 via a circuit breaker. The second DC bus 62 is connected to the input terminal of the second propulsion inverter 17 via a wire; The inverter output terminal of the second propulsion inverter 17 is connected to the input terminal of the second propulsion motor 19 via a circuit breaker.

[0032] 7. EMS System Using a high-performance PLC as the core, it connects all system switching devices, power conversion devices, and sensors to achieve centralized management and control of energy management, propulsion control, monitoring and alarm, grid connection and disconnection, battery switching, and emergency dispatch.

[0033] A power control method for a high-voltage AC charging range-extended electric boat, implemented through the aforementioned power system, includes three modes: pure electric operation mode, high-voltage charging mode while moored, and low-voltage charging mode while moored; details are as follows: Pure electric operation mode: Several lithium battery groups are divided into ready-to-use lithium battery groups and standby lithium battery groups. The EMS system puts the ready-to-use lithium battery groups into operation and collects the load rate of the entire ship in real time. When the load rate reaches the preset threshold, it sends a command to close the power supply switch of the standby lithium battery group and use the standby lithium battery group. When the load rate falls below the preset threshold, the standby battery group is manually or automatically deactivated.

[0034] Manual operation involves human intervention, where the circuit breaker at the output terminal of the lithium battery pack is tripped by pressing a button on the DC bus. Automatic operation involves the EMS automatically sending a hard signal to the circuit breaker at the output terminal of the lithium battery pack when it determines that the load rate is below a set threshold, thus automatically tripping the circuit breaker.

[0035] High-voltage charging mode while the ship is moored: When the ship is moored, the AC6000V cable on shore is connected to the high-voltage AC socket box 1. After the EMS detects that the shore power signal is normal, the circuit breaker between the AC high-voltage socket box 1 and the AC high-voltage connection panel 2, and the circuit breaker between the high-voltage AC connection panel 2 and the high-voltage AC transformer 3 are closed, and the voltage is reduced to AC690V. At the same time, the DC bus tie solid-state switch 63 is disconnected. After rectification by the first shore rectifier 4 and the second shore rectifier 5, the power is connected to the first DC bus 61 and the second DC bus 62. The battery converter is started to charge the lithium battery packs connected to the first DC bus 61 and the second DC bus 62 respectively. The remaining battery power is monitored in real time, and the charging stops automatically when the battery is fully charged. The battery charging process is as follows: In the first stage, constant current charging is used. When the voltage of a single battery cell reaches the charging voltage threshold (e.g., 3.6~3.65V), it automatically enters the second stage. In the second stage, constant voltage charging is used to maintain a constant voltage. The charging current will gradually decrease. When the charging current is extremely small (e.g., around 0.02C or the set cutoff current), the rectifier and related circuit breakers will be automatically turned off, and charging will stop.

[0036] Low-voltage charging mode while the ship is moored: When the ship is moored, the low-voltage shore power box 13 is connected to the shore AC400V low-voltage shore power. The EMS system adjusts the ship's power grid to synchronize with the shore power. The AC400V low-voltage shore power flows into the AC distribution module and into the daily loads connected to the AC distribution module. After the EMS system completely transfers the daily loads to be powered by the AC400V low-voltage shore power, it stops the daily inverter. The transformer and inverter are closed and reversed to rectify the AC400V low-voltage shore power into DC1000V and connect it to the first AC distribution board 11. The lithium battery pack is charged through the battery converter. After charging is completed, the ship's own power supply is restored first, and then the shore power is disconnected.

[0037] The specific method by which the above-mentioned EMS system completely transfers the daily load to AC400V low-voltage shore power is as follows: The EMS system regulates the two daily inverters on board so that the power output to the AC power distribution module is completely consistent with the AC400V low-voltage shore power supply in terms of voltage, frequency and phase, thus creating the necessary conditions for closing the circuit and integrating the AC400V low-voltage shore power into the ship's power grid.

[0038] Example 2: A power control method for a high-voltage AC charging range-extended electric boat A power control method for a high-voltage AC charging range-extended electric boat, based on the power system of Embodiment 1, includes four operating modes: The operating modes include pure electric operation mode, parking high-voltage charging mode, parking low-voltage charging mode, and emergency charging mode. (a) Pure electric operation mode 1.1 Initial State The EMS system controls the closing of the disconnect switches of the first lithium battery pack 20 and the third lithium battery pack 22, and starts the corresponding first battery converter 24 and third battery converter 26, boosting the battery DC772V to DC1000V, and outputting electrical energy to the first DC bus 61 and the second DC bus 62 respectively. The EMS system controls the disconnect switches of the second lithium battery pack 21 and the fourth lithium battery pack 23 to open, and the corresponding second battery converter 25 and the fourth battery converter 27 to shut down and serve as backup battery packs.

[0039] 1.2 Propulsion System Power Supply Control The EMS system controls the start-up of the first propulsion inverter 16 and the second propulsion inverter 17, converting the DC1000V of the first DC bus 61 and the second DC bus 62 into AC690V; Close the circuit breaker between the first propulsion inverter 16 and the first propulsion motor 18, and the circuit breaker between the second propulsion inverter 17 and the second propulsion motor 19, to drive the first propulsion motor 18 and the second propulsion motor 19 to operate.

[0040] 1.3 Daily power supply control The EMS system controls the first daily inverter 7 and the second daily inverter 8 to work in inverter mode, converting DC1000V to AC620V. After being stepped down to AC400V by the first daytime transformer 9 and the second daytime transformer 10, the circuit breaker between the transformer and the AC busbar is closed to supply power to the first AC busbar 111 and the second AC busbar 112 of the first AC distribution board 11. The first AC distribution board 11 supplies AC380V power to the daily load, and at the same time supplies power to the second AC distribution board 12 via the first lighting transformer 14 and the second lighting transformer 15, supplying AC220V power to the load.

[0041] 1.4 Load Regulation The EMS system collects the ship's load factor in real time. When the load factor reaches 95%: The automatic control closes the disconnect switches of the second lithium battery pack 21 and the fourth lithium battery pack 23, starts the second battery converter 25 and the fourth battery converter 27, and puts the backup battery pack into operation to improve the power supply capacity. When the load rate drops below 95%, the EMS system automatically controls the standby battery pack disconnect switch to open, or manually controls the standby battery pack disconnect switch to open, thus disconnecting the standby battery pack.

[0042] In this circuit design, the electrical energy flows sequentially as follows: Power supply for the propulsion system: lithium battery pack, battery converter, DC busbar, propulsion inverter, propulsion motor; Power supply for loads: lithium battery packs, battery converters, DC busbars, household inverters, household transformers, AC distribution boards, and household loads (external loads).

[0043] (ii) Parking High-Voltage Charging Mode 2.1 Initial State When the electric boat enters the berthing mode, the first propulsion inverter 16 and the second propulsion inverter 17 stop, and the circuit breaker connected to the first propulsion motor 18 and the second propulsion motor 19 is opened; the daily load is powered by shore power or is temporarily shut down.

[0044] 2.2 High-voltage shore power access detection Connect the AC 6000V high-voltage shore power supply to the high-voltage AC socket box 1. After the EMS system detects that the voltage and insulation parameters are normal, execute the closing command.

[0045] 2.3 High-voltage charging circuit is turned on The EMS system controls the closing of the circuit breaker between the high-voltage AC socket box 1 and the high-voltage AC connection panel 2; The circuit breaker between the high-voltage AC connection panel 2 and the high-voltage AC transformer 3 is closed, and the AC6000V shore power is stepped down to AC690V AC power by the transformer.

[0046] 2.4 Shore power rectification and DC bus disconnection The EMS system controls the start of the first shore rectifier 4 and the second shore rectifier 5 to rectify the AC690V AC power into DC1000V DC power. The EMS system controls the DC bus tie solid-state switch 63 to open, electrically isolating the first DC bus 61 from the second DC bus 62 to prevent charging circulating current.

[0047] 2.5L lithium battery pack charging The EMS system controls the closing of the isolation switches of the first to fourth lithium battery packs, and the corresponding first to fourth battery inverters switch to charging mode. The first shore power rectifier 4 charges the first lithium battery pack 20 and the second lithium battery pack 21 via the first DC bus 61, the first battery converter 24 and the second battery converter 25. The second shore power rectifier 5 charges the third lithium battery pack 22 and the fourth lithium battery pack 23 via the second DC bus 62, the third battery converter 26 and the fourth battery converter 27. The EMS system monitors the battery level in real time and automatically stops charging once fully charged.

[0048] Electrical power flow in the circuit: AC6000V shore power, high-voltage AC socket box 1, high-voltage AC connection panel 2, high-voltage transformer 3, shore power rectifier, DC busbar, battery converter, lithium battery pack.

[0049] (iii) Parking low-voltage charging mode (AC400V low-voltage shore power charging) 3.1 Initial State When the electric boat enters the berthing mode, the DC bus coupler solid-state switch 63 closes, the propulsion system stops, and the electrical interlock protection takes effect.

[0050] 3.2 Synchronous grid connection of low-voltage shore power The AC400V low-voltage shore power is connected to the low-voltage shore power box 13. The EMS system collects the voltage, frequency, and phase of the shore power and the ship power, and adjusts the ship power parameters to achieve synchronous grid connection. Close the circuit breaker between the low-voltage shore power box 13 and the first AC distribution board 11, and the shore power is connected to the first AC busbar 111 and the second AC busbar 112.

[0051] 3.3 Daily load transfer The EMS system gradually reduces the inverter output power of the first daily inverter 7 and the second daily inverter 8, smoothly transferring the power supply of AC380V and AC220V daily loads to shore power. After the load is completely transferred, the EMS system controls the household inverter to shut down and disconnects the inverter output circuit.

[0052] 3.4 Inverter reverse rectification charging The EMS system controls the first day-use inverter 7 and the second day-use inverter 8 to switch to rectification mode; Close the circuit breakers between the first AC busbar 111 and the first daytime transformer 9, and between the second AC busbar 112 and the second daytime transformer 10; AC400V shore power is stepped up to AC620V by a daytime transformer and sent to the first daytime inverter 7 and the second daytime inverter 8 for rectification into DC1000V DC power, which is then fed into the DC bus. The EMS system starts the first battery converter 24 to the fourth battery converter 27 to deliver DC bus power to the first lithium battery pack 20 to the fourth lithium battery pack 23 to complete charging.

[0053] 3.5 After charging is complete, disconnect the shore power. After charging is completed, the EMS system controls the first daily inverter 7 and the second daily inverter 8 to switch back to the shutdown state; when disconnecting shore power, the first daily inverter 7 and the second daily inverter 8 are started first to transfer the load to the ship's own power supply, and then the circuit breaker of the low-voltage shore power box 13 is disconnected to complete the shore power disconnection.

[0054] Electrical power flow in the circuit: AC400V shore power, low-voltage shore power box 13, AC distribution board, household transformer, household inverter (rectifier mode), DC busbar, battery converter, lithium battery pack.

[0055] (iv) Emergency charging modes include: no shore power, typhoon resistance, and offshore conditions. 4.1 Emergency Activation and Detection The emergency scenario for a ship is defined as the situation when a typhoon is approaching, requiring the ship to leave its usual operating and berthing areas and proceed to a typhoon-sheltered anchorage. However, this anchorage lacks the facilities to replenish the power of the lithium battery packs. Based on historical data, ships typically remain anchored in this typhoon-sheltered anchorage for at least three days. The power consumption during this process primarily consists of daily operating power consumption excluding propulsion. Furthermore, when the battery power is low, for example, when the EMS detects that the remaining power of the lithium battery system is around 20%, the EMS system automatically starts the AC400V backup generator set 28. After confirming normal output, it starts the first generator rectifier 29 and the second generator rectifier 30. Once started, the first generator rectifier 29 and the generator rectifier 30 can charge two of the lithium battery packs, while the other two lithium battery packs continue to power the ship's daily loads.

[0056] 4.2 Electrical Interlocking Control of Charging Branch Electrically interlocked with the electrical interlock circuit breaker 31 of the first generator rectifier 29, only one circuit is allowed to be closed, and the first lithium battery pack 20 and the third lithium battery pack 22 are not charged at the same time. Electrically interlocked with the electrical interlock circuit breaker 31 of the second generator rectifier 30, only one circuit is allowed to be closed, and the second lithium battery pack 21 and the fourth lithium battery pack 23 are not charged at the same time. Ensure that the system can charge a maximum of two lithium battery packs simultaneously.

[0057] 4.3 Independent charging protection After detection by the EMS system, the charging scheme prioritizes charging the lithium battery packs with lower battery levels, while the uncharged lithium battery packs continue to supply power to the load. The EMS system monitors the status throughout the process.

[0058] The electrical energy flows in the circuit as follows: Charging: 28 standby generator sets, rectifier generators, 31 electrical interlocking circuit breakers, and lithium battery packs (independent charging, not connected to the DC busbar). Propulsion system power supply: uncharged lithium battery pack, battery converter, first DC bus 61 / second DC bus 62, propulsion inverter, propulsion motor; Daily load power supply: Uncharged lithium battery pack, battery converter, first DC bus 61 / second DC bus 62, daily inverter, daily transformer, AC distribution board, power supply to daily load (external load).

[0059] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A power system for a high-voltage AC charging range-extended electric boat, characterized in that, Includes lithium battery modules, DC power distribution modules, AC power distribution modules, high-voltage AC charging modules, low-voltage shore power boxes, propulsion modules, daily loads, and EMS systems; The lithium battery module includes several lithium battery packs and is connected to the DC bus of the DC power distribution module via corresponding battery converters. The DC power distribution module includes a DC power distribution board and a DC bus tie solid-state switch. The DC bus of the DC power distribution board is divided into a first DC bus and a second DC bus. The first DC bus and the second DC bus are connected by the DC bus tie solid-state switch. Under normal operating conditions, when the DC bus tie solid-state switch is closed, the first DC bus and the second DC bus are connected in parallel to supply power. The high-voltage AC charging module includes an AC high-voltage socket box, a high-voltage AC connection panel, a high-voltage AC transformer, and two sets of shore power rectifiers. It can step down the shore power supply, rectify it through the rectifiers, and then connect it to the DC bus. It charges the lithium battery pack through the battery converter. In the charging mode, the DC bus tie solid-state switch is turned on to disconnect the first DC bus and the second DC bus. The AC power distribution module includes a first AC power distribution board and a second AC power distribution board connected to the first AC power distribution board. The busbars of the first AC power distribution board are divided into a first AC busbar and a second AC busbar. The first AC busbar and the second AC busbar are connected via an AC bus tie switch. The first AC power distribution board is connected to the DC power distribution module through an inverter and a transformer. The AC power distribution module is connected to the power input terminal of the household load. The output terminal of the low-voltage shore power box is connected to the first AC power distribution board of the AC power distribution module. It can be reverse rectified to the DC power distribution module through the transformer and inverter of the AC power distribution module. The DC power distribution module is connected to the lithium battery pack through the battery converter. The low-voltage AC shore power output by the low-voltage shore power box can charge the lithium battery pack. The propulsion module includes at least two propulsion motors with adjustable frequency or power. The propulsion motors are connected to the DC busbar through a propulsion inverter, which converts DC power into AC power to drive the propulsion motors. The control terminal of the EMS system is connected to the control terminals of all switching devices, power conversion devices, power devices, and monitoring sensors in the system.

2. The power system of a high-voltage AC charging range-extended electric boat according to claim 1, characterized in that, The two shore rectifiers in the high-voltage AC charging module include a first shore rectifier and a second shore rectifier. The connection relationship between the high-voltage AC charging module and the DC power distribution module is as follows: the input terminal of the AC high-voltage socket box is connected to the shore AC 6000V high-voltage AC shore power; the output terminal of the AC high-voltage socket box is connected to the AC high-voltage connection panel via a circuit breaker; the output terminal of the high-voltage AC connection panel is connected to the input terminal of the high-voltage AC transformer via a circuit breaker; the step-down output terminal of the high-voltage AC transformer is connected to the AC input terminal of the first shore rectifier and the AC input terminal of the second shore rectifier via wires; the DC output terminal of the first shore rectifier is connected to the first DC busbar via a fuse; and the DC output terminal of the second shore rectifier is connected to the second DC busbar via a fuse.

3. The power system of a high-voltage AC charging range-extended electric boat according to claim 1, characterized in that, The AC power distribution module includes a first daily-use transformer and a second daily-use transformer; the AC power distribution module also includes a first daily-use inverter and a second daily-use inverter. The specific connection relationship between the AC power distribution module and the DC power distribution module is as follows: The output terminal of the shore AC400V low-voltage AC shore power is connected to the input terminal of the low-voltage shore power box via a wire. The output terminal of the low-voltage shore power box is connected to the first AC busbar and the second AC busbar via a circuit breaker. The first AC busbar is connected to one end of the first daily transformer via a circuit breaker. The other end of the first daily transformer is connected to one end of the first daily inverter via a wire. The other end of the first daily inverter is connected to the first DC busbar via a fuse. The output terminals of the second AC busbar are connected to one end of the second daily transformer via circuit breakers. The other end of the second daily transformer is connected to one end of the second daily inverter via wires. The other end of the second daily inverter is connected to the second DC busbar via fuses.

4. The power system of a high-voltage AC charging range-extended electric boat according to claim 1, characterized in that, The lithium battery module has four lithium batteries; the connection relationship between the lithium battery module and the DC power distribution module is as follows: The first lithium battery pack is connected to one end of the first battery converter via a disconnecting switch, and the other end of the first battery converter is connected to the first DC bus via a fuse. The second lithium battery pack is connected to one end of the second battery converter via a disconnecting switch, and the other end of the second battery converter is connected to the first DC bus via a fuse. The third lithium battery pack is connected to one end of the third battery converter via a disconnecting switch, and the other end of the third battery converter is connected to the second DC bus via a fuse. The fourth lithium battery pack is connected to one end of the fourth battery converter via a disconnecting switch, and the other end of the fourth battery converter is connected to the second DC bus via a fuse.

5. The power system of a high-voltage AC charging range-extended electric boat according to claim 1, characterized in that, The connection relationships between the first AC distribution board and the second AC distribution board are as follows: The first AC busbar is connected to one end of the first lighting transformer via a circuit breaker, and the other end of the first lighting transformer is connected to the second AC distribution board. The second AC busbar is connected to one end of the second lighting transformer via a circuit breaker, and the other end of the second lighting transformer is connected to the second AC distribution board via a wire. The first AC distribution board is connected to the input terminal of the daily load via a circuit breaker, providing AC380V AC power to the daily load; The second AC distribution board is connected to the input terminal of the external load via a circuit breaker to provide AC220V AC power to the external load.

6. The power system of a high-voltage AC charging range-extended electric boat according to claim 1, characterized in that, The propulsion module has two propulsion motors, namely a first propulsion motor and a second propulsion motor; the connection relationship between the propulsion module and the DC power distribution module is as follows: The first DC bus is connected to the input terminal of the first propulsion inverter via a wire, and the inverter output terminal of the first propulsion inverter is connected to the input terminal of the first propulsion motor via a circuit breaker; The output terminal of the second DC busbar is connected to the input terminal of the second drive inverter via a wire; The inverter output of the second propulsion inverter is connected to the input of the second propulsion motor via a circuit breaker.

7. The power system of a high-voltage AC charging range-extended electric boat according to claim 2, characterized in that, It also includes a backup generator set, which has a voltage of 400V AC and is directly connected to the lithium battery pack via a pair of generator rectifiers to achieve emergency charging; The pair of power generation rectifiers includes a first power generation rectifier and a second power generation rectifier. The DC output terminal of the first generator rectifier is connected to the charging input terminal of the first lithium battery pack and the second lithium battery pack via an electrical interlocking circuit breaker. The DC output terminal of the second generator rectifier is connected to the charging input terminals of the third and fourth lithium battery packs via an electrical interlock circuit breaker. The electrical interlocking circuit breaker includes two circuit breakers, and when the two circuit breakers are in operation, only one of them can be closed.

8. The power system of a high-voltage AC charging range-extended electric boat according to claim 1, characterized in that, All lithium battery systems are equipped with a battery management system to monitor and manage battery status.

9. A power control method for a high-voltage AC charging range-extended electric boat, implemented through the power system of a high-voltage AC charging range-extended electric boat as described in claim 7, characterized in that, The control method includes three modes: pure electric operation mode, parking high-voltage charging mode, and parking low-voltage charging mode; the details are as follows: Pure electric operation mode: Several lithium battery groups are divided into ready-to-use lithium battery groups and standby lithium battery groups. The EMS system puts the ready-to-use lithium battery groups into operation and collects the load rate of the entire ship in real time. When the load rate reaches the preset threshold, it sends a command to close the power supply switch of the standby lithium battery group and uses the standby lithium battery group. When the load rate falls below the preset threshold, the standby battery group is manually or automatically deactivated. High-voltage charging mode while the ship is moored: When the ship is moored, the AC 6000V cable on shore is connected to the high-voltage AC socket box. After the EMS detects that the shore power signal is normal, the circuit breaker between the AC high-voltage socket box and the AC high-voltage connection panel, and the circuit breaker between the high-voltage AC connection panel and the high-voltage AC transformer are closed, and the voltage is reduced to AC 690V. At the same time, the DC bus tie solid-state switch is disconnected. After rectification by the first shore power rectifier and the second rectifier, the power is connected to the first DC bus and the second DC bus. The battery converter is started to charge the lithium battery packs connected to the first DC bus and the second DC bus respectively. The remaining battery power is monitored in real time, and the charging stops automatically when the battery is fully charged. Low-voltage charging mode while the ship is moored: When the ship is moored, the low-voltage shore power box is connected to the shore AC400V low-voltage AC shore power. The EMS system adjusts the ship's power grid to synchronize with the shore power. The AC400V low-voltage AC shore power flows into the AC distribution module and into the daily loads connected to the AC distribution module. After the EMS system completely transfers the daily loads to be powered by the AC400V low-voltage AC shore power, it stops the daily inverter. The transformer and inverter are closed and reversed to rectify the AC400V low-voltage AC shore power into DC1000V DC power, which is then connected to the first AC distribution board. The lithium battery pack is charged through the battery converter. After charging is completed, the ship's own power supply is restored first, and then the shore power is disconnected.

10. The power control method for a high-voltage AC charging range-extended electric boat according to claim 9, characterized in that, It also includes an emergency charging mode, the control method of which is as follows: Emergency charging mode: When a ship enters an emergency scenario, including a long-term typhoon resistance scenario and a scenario where it cannot dock, the EMS system will automatically start the backup generator set when the battery power is low. After the generator set output is detected to be normal, the generator rectifier will be closed, and the two lithium batteries with the lowest power will be identified first, and the constant voltage or constant current charging mode will be started. During the charging process, the uncharged lithium battery pack continues to supply power to the daily load. The EMS monitors the charging status and battery parameters in real time, and immediately stops charging and issues an alarm if any abnormality occurs.

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