Electric ship limping system

Abstract

The invention relates to the technical field of ship electric power systems, and discloses an electric ship limping system which comprises a PDU, a first motor driving system, a second motor driving system, a power generation system, a power battery system, a photovoltaic DCDC system, a low-voltage life battery, a VCU and other components. When a power battery fault, a single-side motor fault or serious power shortage of the whole ship is detected, a corresponding limping mode can be intelligently entered in combination with manual operation of a user, and a high-voltage power supply loop is dynamically reconstructed through a PDU; according to the scheme, fault components are isolated, and the scheme is switched to a standby energy scheme which is directly supplied with power by an extended-range generator, is driven by a single-side motor or is used for emergency charging of a power battery system by utilizing solar energy, so that the ship can still keep limited propelling power under various fault conditions, safe homeward voyage is realized, and the reliability and safety of the electric ship are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of marine electrical systems technology, and more particularly to limp-walking systems for electric ships. Background Technology

[0002] With increasing environmental awareness and the development of electric propulsion technology, electric ships are gradually gaining widespread attention as an alternative to traditional fuel-powered ships. Electric ships typically rely on large-capacity battery systems to power their drive motors, making their electrical systems more complex than those of traditional vessels. During actual operation, electric ships may experience serious problems such as battery system failures, motor drive system failures, or generator (range extender) malfunctions due to environmental factors, mechanical failures, electronic component failures, or human error. Such failures can lead to loss of power or insufficient power, posing navigational safety hazards, especially far from port or in rough seas, where impaired return-to-port capability poses a significant risk.

[0003] The aforementioned and existing related technologies often have the following drawbacks: For some medium and large vessels and vessels requiring long ranges, various energy sources are often integrated into the grid, including fuel-powered generators, hydrogen fuel cells, wind power, and solar power. However, the more systems there are, the greater the chance of malfunction. If a system fails, it can affect the vessel's operation or cause it to stop. Due to the unique operating environment of vessels, when certain systems malfunction, they may be forced to remain stationary and await rescue, or even be forced to move with the current, posing safety risks. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing technology of electric boats has the disadvantage of setting up multiple systems to improve the endurance, which can easily lead to the boat stopping on the spot or drifting with the current due to the failure of one of the systems, which brings danger. To this end, we propose an electric boat limp system.

[0005] To achieve the above objectives, this application adopts the following technical solution: an electric boat limp-walking system, including three power inputs, as detailed below: PDU: Used for distribution in high-voltage power systems, it has multiple built-in relays and fuses and is responsible for controlling the on and off of high-voltage circuits. Electric drive system one: includes electric controller one and drive motor one, used to drive the port side of the electric boat; Electric drive system two: includes electric controller two and drive motor two, used to drive the starboard side of the electric boat; The power generation system consists of the range extender and its controller, which is responsible for generating electricity and charging the power battery system. Power battery system: including battery pack and BMS, used to store energy and provide the main power for electric boat; Photovoltaic DC-DC system: generates electricity through solar energy, outputs low voltage to power low-voltage household batteries, or outputs high voltage in photovoltaic limp mode to charge the power battery system; Low-voltage household batteries: used to provide 24V power to power household appliances; VCU: As the core control unit of the electric boat, it communicates with the PDU, motor drive system, power battery system, power generation system and photovoltaic DC-DC system through the CAN network to coordinate control and provide control commands.

[0006] Preferably, the connection relationship of the relays within the PDU is as follows: The positive terminal of the power battery system is connected to the internal high-voltage bus via the main positive relay K4 inside the PDU; the internal high-voltage bus is connected to the four output branches via relays K1, K2, K3 and K8 respectively: The two ends of relay K1 are connected in parallel with the series-connected pre-charge group R1 and relay K5. The output end of relay K1 is connected to fuse F1, which together are connected to the high voltage input end of motor drive system one, forming the power supply and pre-charge branch of motor drive system one. The two ends of relay K2 are connected in parallel with the series-connected pre-charge group R2 and relay K6. The output end of relay K2 is connected to fuse F2, which together are connected to the high voltage input end of motor drive system two, forming the power supply and pre-charge branch of motor drive system two. The two ends of relay K3 are connected in parallel with the series-connected pre-charge group R3 and relay K7. The output end of relay K3 is connected to fuse F3, which together are connected to the high voltage output end of the power generation system. The high-voltage output terminal of the photovoltaic DC-DC system is connected in series with relay K8 and fuse F4, and then connected back to the internal high-voltage bus.

[0007] Preferably, the system also includes instruments connected to the VCU, which are used to display system signal status, fault information, and corresponding indicator signs in limp mode.

[0008] Preferably, the system also includes a limp switch and a photovoltaic power generation switch that are hardwired to the VCU, the limp switch and the photovoltaic power generation switch being used to activate the electric boat's limp mode and photovoltaic power generation mode, respectively.

[0009] Preferably, the VCU is configured to execute at least three limp-off control modes, including: a mode for power battery system failure, a mode for single-sided motor drive system failure, and a photovoltaic limp-off mode for when the power battery system has low charge and the power generation system cannot charge.

[0010] Preferably, the limp control method of the system includes: The VCU detects system fault signals; In response to a signal triggered by the user via a limp switch or a photovoltaic power generation switch, the VCU determines and enters the corresponding limp mode; VCU reconfigures the high-voltage power supply circuit via PDU, disconnecting faulty components and connecting backup power or healthy components; The VCU controls the remaining available power source to drive the electric boat back to shore.

[0011] Preferably, the mode for a serious failure of the power battery system includes the following steps: a) The VCU detected a fault signal in the power battery system and a limp-out switch activation signal; b) The VCU controls the PDU to disconnect the main positive relay K4 of the power battery system; c) The VCU starts the power generation system to generate electricity; d) The VCU controls the PDU to precharge and power on motor drive system one and motor drive system two in sequence; e) Within the output power range of the power generation system, the VCU requests drive power from motor drive system one and motor drive system two.

[0012] Preferably, the failure mode for a single-sided motor drive system includes the following steps: 1) The VCU detects a fault signal from either motor drive system one or motor drive system two; 2) The VCU controls the output torque of the faulty motor to drop to zero, and after its speed drops below 50 rpm, it controls the PDU to disconnect the main positive relay K1 or K2 of the faulty motor circuit; 3) The VCU controls the healthy motor drive system on the other side to keep working in order to achieve single-sided drive return.

[0013] Preferably, the photovoltaic limp mode includes the following steps: First, the VCU detects that the power battery system's charge is below the safety threshold, the power generation system cannot work, and the photovoltaic power generation switch is turned on. Second, the VCU controls the PDU to disconnect other high-voltage loads except for motor drive system one and motor drive system two; Third, the VCU controls the PDU to close relay K8, enabling the photovoltaic DC-DC system to charge the power battery system in high-voltage output mode; Fourth, after the power battery system's charge is restored, the VCU allows motor drive system one and motor drive system two to be re-energized to provide return power.

[0014] Preferably, the low-voltage output terminal of the photovoltaic DC-DC system is connected to the positive and negative terminals of the low-voltage household battery to charge the low-voltage household battery under normal lighting conditions and to provide low-voltage power to household appliances.

[0015] The technical effects and advantages of this invention are as follows: In this invention, the system can automatically identify and adopt the optimal limp mode under three different fault scenarios, ensuring that the electric boat can still be powered by the range extender or photovoltaic system when the battery, single-sided motor or power supply system fails, ensuring the electric boat can return safely, and improving the overall adaptability and reliability of the electric boat.

[0016] Through VCU intelligent control and PDU high-voltage distribution, this system rationally allocates power and cuts off unnecessary loads in limp mode according to the fault type and remaining resources, maximizing the preservation of energy supply for critical power units. Intelligent power management ensures efficient use of energy, especially in emergency situations with limited resources, extending the electric boat's range.

[0017] When a battery or motor fault is detected, the system can automatically disconnect the fault circuit and cut off the high-voltage current to avoid secondary damage caused by electrical faults. By gradually reducing the torque of the faulty motor and cutting off the high-voltage connection, the system effectively protects the motor and power battery and improves the safety of fault handling.

[0018] This system utilizes the bidirectional output capability of a photovoltaic DC-DC system to achieve high-voltage charging in emergency situations, replenishing the power battery with electrical resources, reducing reliance on the range extender, thereby reducing energy consumption and emissions, and meeting the needs of environmental protection and energy conservation. Attached Figure Description

[0019] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 This is a schematic diagram of the communication control of the electric boat limp-walking system of the present invention; Figure 2 This is a schematic diagram of the working principle circuit of the electric boat limp-walking system of the present invention.

[0020] In the diagram: 1. PDU; 2. Motor drive system one; 3. Motor drive system two; 4. Power generation system; 5. Power battery system; 6. Photovoltaic DC-DC system; 7. Low-voltage household battery; 8. VCU; 9. Instrument; 10. Limp-out switch; 11. Photovoltaic power generation switch. Detailed Implementation

[0021] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0022] Reference Figure 1 and Figure 2 As shown, this invention provides a technical solution: an electric boat limp-action system, the overall structure of which includes a PDU1, a motor drive system 1, a motor drive system 2, a power generation system 3, a power battery system 4, a photovoltaic DC-DC system 6, a low-voltage domestic battery 7, and a VCU8. The VCU8, as the core control unit of the electric boat, communicates with all high-voltage components, including the PDU1, motor drive system 1, motor drive system 2, power battery system 5, power generation system 4, and photovoltaic DC-DC system 6, via a CAN (Controller Area Network). This CAN network communication method ensures real-time data sharing and rapid transmission of control commands between components, thereby achieving system-level coordinated control. The VCU8 is responsible for receiving operating status information, fault signals, and user operation commands from each component, and making decisions based on this information, issuing corresponding control commands to the PDU1 and each power component to coordinate the operation of the entire power system. Especially in the event of a fault, it can provide a flexible limp-action control strategy.

[0023] The functions of each component are as follows: PDU1 (Power Distribution Unit): The high-voltage power distribution unit is the central hub of the entire high-voltage power system. It integrates multiple high-voltage relays (e.g., K1-K8) and high-voltage fuses (e.g., F1-F4), primarily responsible for distributing and switching high-voltage power current and providing electrical safety protection. VCU8 sends commands to PDU1 via the CAN network to control the closing and opening of the relays, thereby realizing the on / off control of the high-voltage circuit and the reconfiguration of the high-voltage power supply circuit. This is crucial for achieving power switching and isolating faulty components in limp-mode operation.

[0024] Motor drive system 1 (2) and motor drive system 2 (3): These systems respectively include motor controller 1 / 2 and drive motor 1 / 2, used to independently drive the port and starboard propellers or propulsion devices of the electric boat. This dual independent drive design provides the physical basis for a single-sided drive limp-mode. The motor controller is responsible for converting high-voltage direct current into the alternating current required by the drive motor and controlling the speed and torque output of the drive motor. The VCU8 communicates with the motor controller via a CAN network to obtain the motor operating status and issue torque commands.

[0025] Power generation system 4: Typically consists of an internal combustion engine generator set (i.e., a range extender) and its control unit. During normal navigation or when the power battery is low, power generation system 4 starts generating electricity and manages energy with the power battery system 5 through its dedicated controller, transferring electrical energy to the power battery system 5 to charge it, thereby extending the electric boat's range. In certain limp-mode operations, power generation system 4 can directly power the electric motor drive system.

[0026] Battery System 5: The main energy storage unit of the electric boat, comprising multiple battery packs and a Battery Management System (BMS). The BMS is responsible for monitoring, managing, and protecting the battery packs, ensuring that the batteries operate within safe operating ranges, and reporting key parameters such as the battery's State of Charge (SoC), voltage, current, and temperature, as well as any fault information, to the VCU8. Battery System 5 is the primary source of high-voltage DC power for Motor Drive Systems 1 / 2 (2 / 3).

[0027] The photovoltaic DC-DC system 6 comprises solar panels and a DC-DC converter. In normal mode, the photovoltaic DC-DC system 6 converts solar energy into stable low-voltage DC power (e.g., 12V or 24V) to power the low-voltage living battery 7 and indirectly provides low-voltage power to the ship's living equipment. In emergency photovoltaic limp mode, controlled by the VCU8, the photovoltaic DC-DC system 6 can switch to high-voltage output mode, converting solar energy into high-voltage DC power and connecting it to the high-voltage bus via relay K8 of the PDU1, thereby charging the power battery system 5, or, in extreme cases, directly powering the motor drive system to provide limited emergency power.

[0028] Low-voltage living battery 7: Typically a 24V or 12V battery pack, used to store electrical energy, specifically providing low-voltage power for auxiliary living equipment on the electric boat, such as navigation equipment, lighting, communication equipment, refrigerators, and water pumps. The photovoltaic DC-DC system 6 charges it in normal mode to maintain its charge.

[0029] VCU8 (Vehicle Control Unit): As the "brain" of the entire limp-walking system, VCU8 not only coordinates the normal operation of each power component, but more importantly, it can monitor the operating status and fault information of all high-voltage components in real time (e.g., through BMS, motor controller, range extender controller, etc.). When VCU8 detects a fault signal or receives a user's limp-walking command, it will enter the corresponding limp-walking mode according to the preset control strategy, and send commands to PDU1 and other relevant power components via the CAN network to reconfigure the high-voltage power supply circuit and adjust the power output to ensure that the vessel maintains its navigation capability to a minimum.

[0030] In addition, the system also includes an instrument 9 connected to the VCU8 to display system signal status (such as battery power, motor speed, power generation, etc.), fault information prompts, and corresponding indicator signs in limp mode (such as "Power battery failure in limp mode", "Single motor in limp mode", "Photovoltaic emergency power", etc.) so that the crew can clearly understand the current working status of the ship and whether there is a fault.

[0031] Example 1: For a detailed explanation of the PDU's internal high-voltage circuit structure and limp-off control mode, please refer to [link / reference]. Figure 2 The high-voltage circuit structure inside the PDU1 of this invention is the core of achieving flexible power distribution and fault isolation.

[0032] Detailed Explanation of PDU1 Internal Relay Connections: The positive terminal (“battery positive”) of the power battery system 5 is connected to the internal high-voltage bus via the main positive relay K4 inside PDU1. This high-voltage bus is the central busbar for high-voltage power distribution. The battery negative terminal is usually directly connected to the negative terminal of the high-voltage bus or connected via a separate negative relay (not shown in detail for simplicity, but is generally considered to be a complete circuit).

[0033] The internal high-voltage busbar is connected to each high-voltage load / power supply via the following relays and branches: The power supply and pre-charge branch of motor drive system 2 consists of relay K1 (main relay) and its parallel series pre-charge group R1, together with relay K5 (pre-charge relay). Pre-charge relay K5 is responsible for slowly charging the internal capacitor of motor drive system 2 through pre-charge resistor R1 before the main relay K1 closes, to prevent excessive inrush current at the moment of closing. After pre-charging is complete, K5 opens, K1 closes, and normal power is supplied to the high-voltage input terminal of motor drive system 2. This branch also has a fuse F1 connected in series to provide overcurrent protection.

[0034] The power supply and pre-charge branch of motor drive system 2 (3) is similar in composition and working principle to that of motor drive system 1 (2). It consists of relay K2 (main relay), its parallel series pre-charge group R2, and relay K6 (pre-charge relay), connected in series with fuse F2. This branch supplies power to the high-voltage input terminal of motor drive system 2 (3) and performs pre-charge.

[0035] The power supply branch of the power generation system 4 consists of relay K3 (main relay) and its parallel series pre-charge group R3 and relay K7 (pre-charge relay), with fuse F3 connected in series. It is used to connect the high-voltage power generated by the power generation system 4 to the high-voltage bus and perform pre-charging, usually to charge the power battery system 5 or directly supply power to motor drive system one / two (2 / 3).

[0036] The high-voltage output branch of the photovoltaic DC-DC system 6: The high-voltage output terminal of the photovoltaic DC-DC system 6 is connected back to the internal high-voltage bus of PDU1 through a series relay K8 (main relay) and fuse F4. This allows the photovoltaic DC-DC system 6 to feed the high-voltage electrical energy generated by solar energy back to the high-voltage bus in photovoltaic limp mode, thereby realizing the backup function of charging the power battery system 5 or directly powering the motor drive system.

[0037] Limp-off switch 10 and photovoltaic power generation switch 11: The system also includes two physical switches hard-wired to the VCU8: limp-off switch 10 and photovoltaic power generation switch 11. These switches are typically independent self-locking or jog buttons mounted on the cab panel. They provide an intuitive and reliable human-machine interface. The VCU8 directly receives the physical button signals from these two switches in response to the user's operational intent. Limp-off switch 10 is used by the crew to manually activate a general limp-off mode, such as for a power battery or single-side motor failure, in the event of a power system failure. Photovoltaic power generation switch 11 is used to manually activate the high-voltage output function of the photovoltaic DC-DC system 6 under specific conditions, such as low power battery charge and power generation system failure, entering photovoltaic limp-off mode.

[0038] VCU8 Limp Control Modes: The VCU8 is configured to execute at least three key limp control modes, based on the VCU's detection of system fault signals and signals triggered by the user via an external switch: The following mode is activated for power battery system 5 failures: When VCU8 receives a critical fault alarm from BMS (such as overvoltage, undervoltage, overtemperature, insulation fault, etc.) or the power battery system becomes unresponsive, and / or when the user issues a command via limp switch 10, VCU8 will activate this mode. The goal of this mode is to isolate the faulty power battery and utilize generator system 4 as an alternative main power source to power the motor drive system.

[0039] For single-side motor drive system one / two (2 / 3) failure mode: When VCU8 receives a serious fault (such as motor overheating, controller failure, stall, etc.) in one side of the motor drive system (e.g., motor drive system one 2) from the motor controller, or when the user selects single-side drive via limp switch 10, VCU8 will activate this mode. The goal of this mode is to isolate the faulty motor drive system and utilize the healthy motor drive system on the other side to provide single-side power for limited return.

[0040] For the photovoltaic limp mode when the power battery system 5 has low charge and the power generation system 4 cannot charge: This is a special and extreme emergency mode. When the VCU8 detects that the state of charge (SoC) of the power battery system 5 is below a preset safety threshold (e.g., 20%), and simultaneously detects that the power generation system 4 cannot start or generate electricity due to its own malfunction (e.g., fuel depletion, engine failure), and the user activates this mode via the photovoltaic power generation switch 11, the VCU8 will activate this mode. The goal of this mode is to maximize the use of clean solar energy to charge the power battery, maintaining the ship's most basic electrical needs and allowing for a longer return journey.

[0041] Example 2: The detailed process of the limp control method, the limp control method of the present invention, includes the following main steps: Step S110: Detect system fault signals via VCU8. VCU8 monitors the operating status of all core high-voltage components in real time. This includes: obtaining battery charge, voltage, temperature, and fault codes from the BMS of the power battery system 5; obtaining motor speed, torque, temperature, controller status, and fault codes from the controllers of motor drive systems 1 / 2 (2 / 3); obtaining its operating status, power generation, and fault codes from the controller of the power generation system 4; and obtaining its operating mode and status from the photovoltaic DC-DC system 6. VCU8 continuously analyzes this data, and once an anomaly or fault alarm is detected, it is identified as a fault signal.

[0042] Step S120: In response to a signal triggered by the user via limp switch 10 or photovoltaic power generation switch 11, VCU8 determines and enters the corresponding limp mode. When VCU8 detects a fault signal, it does not immediately and automatically enter limp mode; instead, the user usually needs to confirm or select it via limp switch 10 or photovoltaic power generation switch 11. For example, when a power battery fault is detected, VCU8 will display "Power battery fault, please activate limp mode" on instrument panel 9, waiting for the user to press limp switch 10. When VCU8 simultaneously determines the fault type (such as power battery fault, single motor fault, low battery and power generation system failure, etc.) and receives the user's activation signal, it will enter the limp mode most suitable for the current situation according to preset logic.

[0043] Step S130: VCU8 reconfigures the high-voltage power supply circuit via PDU1, disconnecting the faulty component and connecting the backup power supply or healthy component. This is the core action of the limp-mode. Based on the determined limp-mode, VCU8 generates corresponding relay control commands and sends them to PDU1 via the CAN network. The relays (K1-K8) in PDU1 will act according to the commands, such as disconnecting the faulty component (e.g., the faulty battery system K4 relay), or disconnecting the faulty motor drive system (e.g., K1 relay), or disconnecting unnecessary loads, while simultaneously closing the relays of the backup component (e.g., the relay connected to the generator system K3 relay) or healthy component, thereby adjusting the flow path of high-voltage power.

[0044] Step S140: VCU8 controls the remaining available power sources to drive the electric boat back to shore. After the high-voltage circuit is reconfigured, VCU8 adjusts the boat's power output strategy based on the currently available power sources (such as a generator system, a healthy single-sided motor drive system, or a power battery supplemented by a photovoltaic system). VCU8 sends new torque or speed commands to the healthy motor controller to operate within its limited power range, ensuring the boat can return to shore with minimal effort. Simultaneously, instrument 9 displays the current limp-home mode and relevant operating parameters.

[0045] Example 3: To address the limp-mode caused by severe failure of the power battery system, when the power battery system 5 experiences a severe failure and cannot continue to supply power, this invention provides a limp-mode that utilizes the generator system 4 to replace battery power supply. The specific steps of this mode are as follows: Step S210: VCU8 detects a fault signal from the power battery system 5 and an on signal from the limp switch 10. At this time, the BMS may report dangerous conditions such as battery pack overcurrent, overvoltage, undervoltage, overtemperature, or internal short circuit, and request disconnection. VCU8 receives such warnings and enters the emergency mode after confirming that the user has activated the emergency mode by pressing the limp switch 10.

[0046] Step S220: VCU8 controls PDU1 to disconnect the main positive relay K4 of the power battery system 5. This is to completely isolate the faulty power battery system 5 and prevent the fault from spreading or causing further damage to the system. After K4 is disconnected, the power battery system 5 no longer directly supplies power to the high-voltage bus.

[0047] Step S230: VCU8 starts the power generation system 4 to generate electricity. VCU8 sends a start command to the controller of the power generation system 4 via the CAN network. The power generation system 4 starts its internal combustion engine and begins to run the generator, converting mechanical energy into electrical energy.

[0048] Step S240: VCU8 controls PDU1 to precharge and power on motor drive system 2 and motor drive system 3 sequentially. After the generator system 4 outputs a stable power, VCU8 instructs PDU1 to execute the pre-charging procedure, first closing relays K7 (pre-charging relay) and K3 (main relay) to connect generator system 4 to the high-voltage bus. Then, referring to the pre-charging process described in Embodiment 1, using the high-voltage bus of PDU1, first closing K5 (pre-charging relay) to precharge motor drive system 2 through R1; after pre-charging is completed, K5 is opened and K1 (main relay) is closed to complete power-on. Next, the same operation is performed on motor drive system 3: closing K6 to pre-charge through R2; after pre-charging is completed, K6 is opened and K2 is closed. This step ensures that motor drive systems 1 / 2 (2 / 3) do not generate excessive inrush current when receiving power from generator system 4, protecting the system equipment.

[0049] Step S250: Within the output power range of the power generation system 4, the VCU8 requests drive power from motor drive systems 2 and 3. Since the power generation system 4 is the only power source at this time, its power output is typically less than the peak power provided by the battery system 5. Therefore, the VCU8 calculates and issues limiting torque commands to the left and right motor drive systems 2 and 3 based on the real-time output power capability of the power generation system 4. The throttle signals operated by the crew will be limited by the VCU8 to a lower range to ensure that the total power consumption of the motor drive systems does not exceed the maximum power generation capacity of the power generation system 4, thereby maintaining the ship's stable navigation at a limited speed.

[0050] Example 4: Limp mode for single-sided motor drive system failure, when one side of the electric boat's motor... When the drive system fails, this invention supports single-sided drive using the healthy motor on the other side to achieve return to base. The specific steps of this mode are as follows: Step S310: VCU8 detects a fault signal from motor drive system 1 (2) or motor drive system 2 (3). The fault signal may include an internal fault alarm of the motor controller (e.g., overcurrent, overheating, control unit malfunction) or a fault of the drive motor itself (e.g., winding short circuit, bearing jamming).

[0051] Step S320: VCU8 controls the output torque of the faulty motor to drop to zero, and after its speed drops below 50 rpm, controls PDU1 to disconnect the main positive relay K1 or K2 in the circuit of the faulty motor. Once a fault is identified, VCU8 immediately sends a command to the motor controller on the faulty side to gradually reduce its output torque until it reaches zero, preventing the fault from worsening. At the same time, VCU8 monitors the speed of the faulty motor. When its speed drops to a safe threshold (e.g., below 50 rpm, ensuring the motor has essentially stopped or is not being towed harmfully), VCU8 sends a command to PDU1 to disconnect the main positive relay connected to the drive system of the faulty motor (e.g., disconnect K1 if the motor drive system 2 is faulty), thereby completely cutting off the power supply to the faulty component, isolating the fault, and preventing safety hazards.

[0052] Step S330: VCU8 controls the other healthy motor drive system to remain operational to achieve single-sided drive return. At this time, the healthy motor drive system on the other side (e.g., motor drive system 3 if motor drive system 2 fails) will continue to be powered by battery system 5 or generator system 4 (if the generator system is activated). VCU8 will continue to adjust the output power of the healthy motor drive system according to the crew's steering commands, but the impact of single-sided drive on the ship's course stability needs to be considered. Typically, VCU8 will provide a tuned steering logic to help the crew control the ship more smoothly for straight-line navigation or turning, for example, by compensating for rudder angle input through algorithms to counteract the yaw moment caused by single-sided thrust, thereby achieving a relatively controlled return. Instrument 9 will display the indication "Single-sided motor drive limp."

[0053] Example 5: The photovoltaic limp mode is an emergency mode that uses solar energy to charge the power battery system 5 in extreme situations, specifically when the power battery system 5 is severely depleted and the power generation system 4 (range extender) is also unable to operate. The specific steps of this mode are as follows: Step S410: The VCU8 detects that the power battery system 5's charge is below the safety threshold, the power generation system 4 is not working, and the photovoltaic power generation switch 11 is activated. The "safety threshold" typically refers to 15% to 20% of the total battery capacity. Below this value, the battery may enter deep discharge, damaging its lifespan or preventing it from providing sufficient power. The VCU8 monitors the SoC information reported by the BMS. Simultaneously, the VCU8 checks the controller status of the power generation system 4 to confirm its normal operation or any fault alarms. The system will only enter this mode when all the above conditions are met and the crew manually presses the photovoltaic power generation switch 11 for confirmation.

[0054] Step S420: VCU8 controls PDU1 to disconnect all high-voltage loads except for motor drive system 2 and motor drive system 3. In photovoltaic limp mode, energy supply is extremely limited. To maximize solar energy utilization, VCU8 instructs PDU1 to disconnect all non-essential high-voltage loads. This may include, but is not limited to, high-power devices such as backup high-voltage heating systems, high-voltage heating or cooling units in air conditioning systems, to ensure that limited power is prioritized for charging the power battery system 5. However, the two motor drive systems remain connected at this time to provide return power once the power battery is restored.

[0055] Step S430: VCU8 controls PDU1 to close relay K8, enabling the photovoltaic DC-DC system 6 to charge the power battery system 5 in high-voltage output mode. This is the core action of the photovoltaic limp-mode. VCU8 instructs PDU1 to close the high-voltage feedback relay K8 connected to the photovoltaic DC-DC system 6. Simultaneously, VCU8 instructs the photovoltaic DC-DC system 6 to switch its operating mode to high-voltage output mode. At this time, the energy captured by the solar panels is converted into high-voltage DC power by the photovoltaic DC-DC system 6, enters the high-voltage bus of PDU1 via K8, and finally enters the power battery system 5 for charging. The charging rate will depend on the light intensity and the conversion efficiency of the DC-DC system, and is usually a relatively low power. Instrument 9 will display indicators such as "Photovoltaic charging in progress" and "Photovoltaic emergency power".

[0056] Step S440: After the power battery system 5 has been restored, VCU8 allows motor drive system 2 and motor drive system 3 to be re-energized to provide return power. VCU8 will continuously monitor the SoC of power battery system 5. When the battery charge through photovoltaic DC-DC system 6 reaches a preset minimum acceptable value (e.g., enough to drive the motors for 1-2 hours), VCU8 will remove the power disable status of motor drive systems 1 / 2 (2 / 3) (if previously disabled), allowing the crew to operate motor drive systems 1 / 2 (2 / 3) powered by the restored power battery system 5 to continue sailing at a very low speed and return as soon as possible. During this process, photovoltaic DC-DC system 6 may continue to charge power battery system 5 to extend limp time.

[0057] Under normal operating conditions, the low-voltage output terminal of the photovoltaic DC-DC system 6 is directly connected to the positive and negative terminals of the low-voltage life support battery 7. In this mode, the photovoltaic DC-DC system 6 converts solar energy into stable low-voltage DC power to charge the low-voltage life support battery 7 on board, ensuring a continuous power supply for the ship's living equipment (such as lighting, communication, and navigation equipment), and reducing the consumption of power battery energy when there is sufficient sunlight, thus achieving effective energy replenishment and utilization.

[0058] Working Principle: The system uses VCU8 as the core control unit, communicating and coordinating with PDU1, motor drive system 1 (2), motor drive system 2 (3), power generation system 4, power battery system 5, photovoltaic DC-DC system 6, and low-voltage household battery 7 via a CAN network, and monitoring the status of each component in real time. When a fault occurs, VCU8 judges and enters the corresponding limp mode based on the detected fault signal and the user's command triggered by limp switch 10 or photovoltaic power generation switch 11. In the event of a serious fault in power battery system 5, VCU8 controls PDU1 to disconnect the main positive relay K4 to isolate the battery, and simultaneously starts power generation system 4. PDU1 then pre-charges and powers on motor drive system 1 (2) and motor drive system 2 (3) sequentially, enabling range extension. The device directly supplies power to both motors to maintain navigation. In the event of a single-side motor drive system failure, the VCU8 gradually reduces the torque of the faulty motor to zero and disconnects the corresponding main positive relay K1 or K2 after the speed drops below 50 rpm. Subsequently, it relies solely on the healthy side motor drive system to achieve single-side propulsion for return. When the power battery system 5 has low power and the power generation system 4 cannot charge it, the VCU8 enters photovoltaic limp mode, controls the PDU1 to disconnect unnecessary loads and closes relay K8, enabling the photovoltaic DC-DC system 6 to charge the power battery system 5 in high-voltage output mode. Once the power is restored, the motor drive system is allowed to re-energize and provide return power. The entire process is displayed in real time by the instrument 9, providing status and fault prompts to ensure that the ship can safely return using remaining energy under various fault scenarios.

[0059] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. An electric boat limp-walking system, characterized in that, Includes three power inputs, as detailed below: PDU (1): Used for distribution in high-voltage power systems, it has multiple built-in relays and fuses and is responsible for the on / off control of high-voltage circuits. Electric drive system 1 (2): includes electric controller 1 and drive motor 1, used to drive the port side of the electric boat; Motor drive system two (3): includes motor controller two and drive motor two, used to drive the starboard side of the electric boat; The power generation system (4) consists of a range extender and its controller, which is responsible for generating electricity and charging the power battery system (5); Power battery system (5): including battery pack and BMS, used to store energy and provide the main power for electric boat; Photovoltaic DC-DC system (6): generates electricity through solar energy, outputs low voltage to power low-voltage living batteries (7), or outputs high voltage in photovoltaic limp mode to charge power battery system (5); Low-voltage household battery (7): Used to provide 24V power to power household appliances; VCU (8): As the core control unit of the electric boat, it communicates with PDU (1), motor drive system, power battery system (5), power generation system (4) and photovoltaic DC-DC system (6) through CAN network to coordinate control and provide control commands.

2. The electric boat limp-walking system according to claim 1, characterized in that: The connection relationship of the relays in the PDU (1) is as follows: The "positive" terminal of the power battery system (5) is connected to the internal high-voltage bus via the main positive relay K4 inside the PDU (1); the internal high-voltage bus is connected to the four output branches via relays K1, K2, K3 and K8 respectively: The two ends of the relay K1 are connected in parallel with the series-connected pre-charge group R1 and the relay K5. The output end of the relay K1 is connected to the fuse F1, which is connected to the high voltage input end of the motor drive system (2) to form the power supply and pre-charge branch of the motor drive system (2). The two ends of the relay K2 are connected in parallel with the series-connected pre-charge group R2 and the relay K6. The output end of the relay K2 is connected to the fuse F2, which is connected to the high voltage input end of the motor drive system two (3) to form the power supply and pre-charge branch of the motor drive system two (3). The two ends of the relay K3 are connected in parallel to the series-connected pre-charge group R3 and the relay K7. The output end of the relay K3 is connected to the fuse F3, which is connected to the high voltage output end of the power generation system (4). The high-voltage output terminal of the photovoltaic DC-DC system (6) is connected in series with a relay K8 and a fuse F4, and is connected back to the internal high-voltage bus.

3. The electric boat limp-walking system according to claim 2, characterized in that: The system also includes an instrument (9) connected to the VCU (8), which is used to display system signal status, fault information, and display corresponding indicator signs in limp mode.

4. The electric boat limp-walking system according to claim 3, characterized in that: The system also includes a limp switch (10) and a photovoltaic power generation switch (11) that are hardwired to the VCU (8), the limp switch (10) and the photovoltaic power generation switch (11) being used to activate the electric boat limp mode and the photovoltaic power generation mode, respectively.

5. The electric boat limp-walking system according to claim 4, characterized in that: The VCU (8) is configured to execute at least three limp control modes, including: a mode for a fault in the power battery system (5), a mode for a fault in the single-sided motor drive system, and a photovoltaic limp mode for a low charge in the power battery system (5) and when the power generation system (4) cannot charge.

6. The electric boat limp-walking system according to claim 5, characterized in that: The limp control method of the system includes: The VCU (8) is used to detect system fault signals; In response to a signal triggered by the user through the limp switch (10) or the photovoltaic power generation switch (11), the VCU (8) determines and enters the corresponding limp mode; The VCU (8) reconfigures the high-voltage power supply circuit through the PDU (1), disconnects the faulty component and connects the backup power supply or healthy component; The VCU (8) controls the remaining available power source to drive the electric boat back to shore.

7. The electric boat limp-walking system according to claim 6, characterized in that: The mode for a serious fault in the power battery system (5) includes the following steps: a) The VCU (8) detects the fault signal of the power battery system (5) and the limp switch (10) activation signal; b) The VCU (8) controls the PDU (1) to disconnect the main positive relay K4 of the power battery system (5); c) The VCU (8) starts the power generation system (4) to generate electricity; d) The VCU (8) controls the PDU (1) to precharge and power on the motor drive system one (2) and the motor drive system two (3) in sequence; e) The VCU (8) requests drive power from the first motor drive system (2) and the second motor drive system (3) within the output power range of the power generation system (4).

8. The electric boat limp-walking system according to claim 6, characterized in that: The mode for single-sided motor drive system failure includes the following steps: 1) The VCU (8) detects a fault signal of the first motor drive system (2) or the second motor drive system (3); 2) The VCU (8) controls the output torque of the faulty motor to drop to zero, and after its speed is below 50 rpm, controls the PDU (1) to disconnect the main positive relay K1 or K2 of the faulty motor circuit; 3) The VCU (8) controls the healthy motor drive system on the other side to keep working in order to achieve single-side drive return.

9. The electric boat limp-walking system according to claim 6, characterized in that: The photovoltaic limp mode includes the following steps: First, the VCU (8) detects that the power battery system (5) has a charge level lower than the safety threshold, the power generation system (4) cannot work, and the photovoltaic power generation switch (11) is turned on. Second, the VCU (8) controls the PDU (1) to disconnect other high-voltage loads except for the first motor drive system (2) and the second motor drive system (3); Third, the VCU (8) controls the PDU (1) to close relay K8, so that the photovoltaic DC-DC system (6) charges the power battery system (5) in high voltage output mode; Fourth, after the power battery system (5) has recovered its power, the VCU (8) allows the motor drive system one (2) and the motor drive system two (3) to be powered on again to provide return power.

10. The electric boat limp-walking system according to claim 2, characterized in that: The low-voltage output terminal of the photovoltaic DC-DC system (6) is connected to the positive and negative terminals of the low-voltage household battery (7) to charge the low-voltage household battery (7) under normal lighting conditions and to provide low-voltage power to household equipment.

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