A constant power speed control method and system for a marine shaft generator

Abstract

The present application relates to the technical field of ship propulsion and power generation system control, and particularly relates to a constant-power rotating speed control method and system for a ship shaft generator, which comprises the following steps: obtaining operating state parameters of a ship propulsion and power generation system and ship environment parameters; based on the operating state parameters and the ship environment parameters, predicting the influence of shaft generator adjustment action on the rotating speed of a main propulsion diesel engine and the influence of main propulsion diesel engine speed regulation device adjustment action on the output power of the shaft generator, to obtain an interactive prediction result; according to the interactive prediction result, jointly deciding and generating a first adjustment instruction for adjusting the shaft generator and a second adjustment instruction for adjusting the main propulsion diesel engine speed regulation device; by introducing the interactive prediction and joint decision mechanism, the negative interaction between the shaft generator and the main propulsion diesel engine speed regulation device can be effectively identified and eliminated, and the operating stability and safety of the ship in severe sea conditions can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ship propulsion and power generation system control, and particularly relates to a constant power rotating speed control method and system for a ship shaft generator. BACKGROUND

[0002] When a ship is sailing in the open sea, in order to improve energy utilization efficiency, a shaft generator system is usually equipped to convert part of the mechanical energy of the main propulsion diesel engine into electrical energy to power the electrical equipment on the ship, thereby reducing the dependence on independent auxiliary generators, saving fuel and reducing emissions. In order to ensure the stability of the power grid on the ship, the shaft generator usually adopts a constant power control method to strive to keep the output power stable when the speed of the main engine changes. However, in severe sea conditions, this control method faces serious challenges. When the ship encounters severe sea conditions, the ship body shakes violently, causing the propeller load to change greatly and periodically. For example, when the stern is lifted by a wave crest, the propeller immersion depth decreases, the load drops sharply, and the speed of the main propulsion diesel engine rises instantaneously; when the stern sinks with a wave trough, the propeller immersion depth increases, the load increases sharply, and the speed of the main propulsion diesel engine drops sharply. Although the speed regulating device of the main propulsion diesel engine tries to stabilize the speed by increasing or decreasing the fuel injection amount, it is difficult to effectively respond to high-frequency and large-amplitude load changes due to the limitations of mechanical inertia and response speed.

[0003] Since the shaft generator is hard connected with the main propulsion shafting, the severe speed fluctuation of the main propulsion diesel engine will be directly transmitted to the shaft generator. In this case, the traditional constant power control strategy of the shaft generator will have a negative interaction with the speed regulating system of the main propulsion diesel engine. When the speed of the main propulsion diesel engine drops sharply due to increased load, the control system of the shaft generator will greatly increase the excitation current to increase the electromagnetic torque in order to maintain the output power. When the main propulsion diesel engine is already struggling due to high load, the additional strong electromagnetic braking load further exacerbates the trend of the speed of the main propulsion diesel engine to drop. Conversely, when the speed of the main propulsion diesel engine rises due to the propeller out of water, the control system of the shaft generator will quickly reduce the excitation current to reduce the electromagnetic torque, which is equivalent to removing part of the load of the main propulsion diesel engine, making the speed of the main propulsion diesel engine further out of control and increasing the risk of overspeed.

[0004] This uncoordinated control leads to more severe fluctuations in the speed of the shafting, threatening the stability of the power grid and the safety of the propulsion system. Severe torque fluctuations can accelerate the fatigue damage of the propulsion shafting components and even cause shaft breakage. The most dangerous thing is that at the moment when the speed of the main propulsion diesel engine drops, the peak value of the propeller load and the shaft generator load is superimposed, which may exceed the instantaneous output capacity of the main propulsion diesel engine, causing the main propulsion diesel engine to stop, and the ship to lose power in severe sea conditions.

[0005] In view of the above problems, the existing technology needs to be improved. SUMMARY

[0006] The object of the present application is to provide a constant power rotating speed control method and system for a ship shaft generator to solve the problems existing in the prior art.

[0007] In a first aspect, the present application provides a constant power rotating speed control method for a ship shaft generator, comprising the following steps:

[0008] Obtaining operating state parameters of a ship propulsion power generation system and ship environment parameters;

[0009] Based on the operating state parameters and the ship environment parameters, predicting the influence of shaft generator adjustment action on the rotating speed of the main propulsion diesel engine and the influence of the main propulsion diesel engine speed regulation device adjustment action on the output power of the shaft generator to obtain an interactive prediction result;

[0010] According to the interactive prediction result, jointly deciding and generating a first adjustment instruction for adjusting the shaft generator and a second adjustment instruction for adjusting the main propulsion diesel engine speed regulation device;

[0011] The first adjustment instruction and the second adjustment instruction are sent to the controller of the shaft generator and the main propulsion diesel engine speed regulation device respectively to eliminate the negative interaction predicted.

[0012] In a second aspect, a constant power rotating speed control system for a ship shaft generator is provided, comprising:

[0013] A parameter acquisition module is configured to obtain operating state parameters of a ship propulsion power generation system and ship environment parameters;

[0014] An interactive prediction module is configured to predict, based on the operating state parameters and the ship environment parameters, the influence of shaft generator adjustment action on the rotating speed of the main propulsion diesel engine and the influence of the main propulsion diesel engine speed regulation device adjustment action on the output power of the shaft generator to obtain an interactive prediction result;

[0015] A joint decision module is configured to jointly decide and generate, according to the interactive prediction result, a first adjustment instruction for adjusting the shaft generator and a second adjustment instruction for adjusting the main propulsion diesel engine speed regulation device;

[0016] An instruction sending module is configured to send the first adjustment instruction and the second adjustment instruction to the controller of the shaft generator and the main propulsion diesel engine speed regulation device respectively to eliminate the negative interaction predicted.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] The interactive prediction result is obtained by acquiring the operation state parameters of the ship propulsion power generation system and the ship environment parameters, and predicting the influence of the shaft generator adjustment action on the main propulsion diesel engine speed and the influence of the main propulsion diesel engine speed regulation device adjustment action on the shaft generator output power based on the parameters. According to the interactive prediction result, the first adjustment instruction for adjusting the shaft generator and the second adjustment instruction for adjusting the main propulsion diesel engine speed regulation device are generated for joint decision-making, and the instructions are sent to the corresponding controller and speed regulation device. The method can effectively eliminate the negative interaction predicted, thereby solving the problem of incoordination between the shaft generator constant power control and the main propulsion diesel engine speed regulation system in the prior art. Through such cooperative control, the application can significantly reduce the severe fluctuation of the shafting speed of the ship in severe sea conditions, ensure the stable operation of the ship power grid and the safety of the propulsion system, avoid the risk of component fatigue damage and even the shutdown of the main propulsion diesel engine caused by excessive torque fluctuation, and improve the reliability and safety of ship navigation. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The method flowchart of the present application.

[0020] Figure 2 The system structure schematic diagram of the present application.

[0021] In the figure: 201, parameter acquisition module; 202, interactive prediction module; 203, joint decision-making module; 204, instruction sending module. DETAILED DESCRIPTION

[0022] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0023] The terms "first", "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0024] The conventional existing ship shaft generator system in severe sea conditions, due to the propeller load is greatly and periodically changes, resulting in the main propulsion diesel engine speed fluctuation. In this case, the traditional shaft generator constant power control strategy and the main propulsion diesel engine speed regulating system will produce negative interaction, for example, when the main propulsion diesel engine speed drops, the shaft generator to maintain output power will increase the electromagnetic braking load, further exacerbate the speed drop; Conversely, when the speed rises, the shaft generator reduces the electromagnetic torque, which will make the speed further out of control. This uncoordinated control leads to shafting speed fluctuation more severe, threatens the stability of the ship power grid and the safety of the propulsion system, and even may cause the main propulsion diesel engine to shut down.

[0025] In order to better understand the control method proposed in this application, first of all, the key terms involved in it are explained. The ship propulsion and power generation system refers to a comprehensive system composed of main propulsion diesel engine, propulsion shafting, propeller and shaft generator, etc. Its main function is to provide propulsion power for the ship and generate electricity. The operating state parameter refers to the indicators reflecting the current working state of the ship propulsion and power generation system, such as the main propulsion diesel engine speed, load, fuel consumption rate, shaft generator output power, excitation current, etc. The ship environment parameter includes the external conditions affecting the ship operation, such as sea state level, wind speed, wave height, water depth, etc. The shaft generator regulating action usually refers to adjusting the output power and electromagnetic braking torque of the shaft generator by changing the excitation current. The main propulsion diesel engine speed regulating device regulating action refers to adjusting the output torque and speed of the main propulsion diesel engine by controlling the fuel injection amount. The interactive pre-judgment result is the prediction and evaluation of the mutual influence between the shaft generator and the main propulsion diesel engine speed regulating device. The first and second regulating instructions are generated according to the pre-judgment result, which are used to control the specific operation commands of the shaft generator and the main propulsion diesel engine speed regulating device respectively.

[0026] Therefore, the present application provides a kind of ship shaft generator constant power speed control method as shown in Figure 1 The method comprises the following steps:

[0027] S101, obtain the operating state parameter and the ship environment parameter of the ship propulsion and power generation system;

[0028] The acquisition of these parameters can be achieved in various ways. For example, the running state parameters can be collected in real time by various sensors installed on the main propulsion diesel engine, shaft generator, propulsion shafting, etc. such as speed sensors, torque sensors, current sensors, voltage sensors, fuel flow meters, etc. These sensors convert analog signals into digital signals and are aggregated and processed through the ship's integrated automation system (IAS) or data acquisition system (DAS). The ship's environmental parameters can be obtained through the ship's navigation system, weather station, sea state sensor, etc. such as the position information provided by the global positioning system (GPS), the wind speed and direction provided by the anemometer, the wave height and period provided by the wave sensor, etc. The accurate acquisition of these parameters is the basis for subsequent prediction and decision-making.

[0029] S102, based on the running state parameters and the ship's environmental parameters, predicting the influence of the shaft generator adjustment action on the main propulsion diesel engine speed and the influence of the main propulsion diesel engine speed regulation device adjustment action on the shaft generator output power, and obtaining an interactive prediction result;

[0030] The prediction process can be achieved by establishing a dynamic model of the ship's propulsion and power generation system. For example, a mathematical model based on physical principles can be established, which can simulate the relationship between the fuel injection quantity and the output torque of the main propulsion diesel engine, the relationship between the propeller load and the speed, the relationship between the excitation current and the electromagnetic braking torque of the shaft generator, etc. By inputting the current running state parameters and the ship's environmental parameters into the model, and simulating the adjustment action of the shaft generator or the main propulsion diesel engine speed regulation device, the influence of these actions on other parts of the system can be predicted. For example, when the shaft generator needs to increase the output power, its excitation current will increase, thereby generating a larger electromagnetic braking torque, and this model can predict how this additional braking torque will affect the speed of the main propulsion diesel engine. Conversely, when the main propulsion diesel engine speed regulation device adjusts the fuel injection quantity to stabilize the speed, the model can predict how this adjustment will affect the load and output power of the shaft generator. The prediction result can be qualitative, such as "the shaft generator increases the excitation will cause the main propulsion diesel engine speed to drop", or quantitative, such as "the shaft generator increases 10% excitation will cause the main propulsion diesel engine speed to drop 5 RPM".

[0031] S103, according to the interactive prediction result, jointly deciding and generating a first adjustment instruction for adjusting the shaft generator and a second adjustment instruction for adjusting the main propulsion diesel engine speed regulation device;

[0032] The joint decision-making process can be implemented using optimization algorithms. For example, one or more optimization objectives can be set, such as minimizing the main propulsion diesel engine speed fluctuation, minimizing the output power fluctuation of the shaft-driven generator, and minimizing fuel consumption. Based on anticipated negative interactions, the optimization algorithm will simultaneously consider the adjustment capabilities and limitations of both the shaft-driven generator and the main propulsion diesel engine speed governor, seeking an optimal combination of adjustment strategies. For example, if it is predicted that increasing the excitation of the shaft-driven generator will cause an excessive drop in the main propulsion diesel engine speed, the joint decision-making process might generate one instruction requiring the shaft-driven generator to moderately increase its excitation, and another instruction requiring the main propulsion diesel engine speed governor to moderately increase its fuel injection quantity to offset the additional load from the shaft-driven generator, thereby jointly maintaining system stability. The decision results are the first and second adjustment instructions, which can be specific numerical values, such as "increase the shaft-driven generator excitation current by 5%" and "increase the main propulsion diesel engine fuel injection quantity by 2%".

[0033] S104. Send the first adjustment command and the second adjustment command to the controller of the shaft-driven generator and the speed control device of the main propulsion diesel engine respectively to eliminate the anticipated negative interaction.

[0034] Commands can be transmitted via the ship's control network or communication bus. Upon receiving the first regulation command, the shaft generator controller adjusts the excitation system accordingly, thereby altering the output power and electromagnetic braking torque of the shaft generator. Upon receiving the second regulation command, the main propulsion diesel engine speed governor adjusts the fuel injection pump's fuel supply, thereby changing the output torque and speed of the main propulsion diesel engine. This coordinated regulation effectively counteracts or mitigates potential negative interactions between the shaft generator and the main propulsion diesel engine speed governor, thus maintaining higher stability and efficiency of the entire propulsion power generation system under harsh sea conditions.

[0035] The whole working principle of the present application is that by introducing a forward-looking interactive prediction mechanism, the mode of independent operation of the shaft generator and the main propulsion diesel engine speed regulating device in the traditional control system is broken. In severe sea conditions, when the propeller load changes dramatically, the system is no longer simply waiting for the deviation of the speed or power to passively adjust. On the contrary, the present application first obtains the operating state parameters of the ship propulsion and power generation system and the ship environment parameters, which provide comprehensive real-time information for the system. Based on these information, the system can actively predict the influence of the shaft generator adjustment action on the main propulsion diesel engine speed and the influence of the main propulsion diesel engine speed regulating device adjustment action on the shaft generator output power, so as to obtain the interactive prediction result. This means that the system has predicted the potential conflict before the actual negative interaction occurs. Subsequently, according to the interactive prediction result, the system makes a joint decision to generate a coordinated first adjustment instruction and a second adjustment instruction. These instructions are no longer optimized for a single device, but take into account the mutual influence between the two subsystems, aiming to eliminate the negative interaction predicted from the whole. For example, when it is predicted that the shaft generator increases the excitation to maintain constant power, which may cause the main propulsion diesel engine speed to drop excessively, the joint decision will instruct the shaft generator and the main propulsion diesel engine speed regulating device to perform coordinated actions, such as the shaft generator moderately increasing the excitation, while the main propulsion diesel engine speed regulating device moderately increasing the fuel injection amount to provide additional power, so as to maintain the stability of the shaft generator output while avoiding the dramatic fluctuation of the main propulsion diesel engine speed. Finally, these coordinated instructions are sent to the respective controllers to achieve precise and coordinated control of the entire propulsion and power generation system. In this way, the present application can effectively avoid the vicious cycle caused by the traditional control of each system, and significantly improve the running stability, safety and energy efficiency of the ship in complex sea conditions.

[0036] Compared with the prior art, the core innovation of the present application lies in its forward-looking interactive prediction and joint decision mechanism. The traditional ship shaft generator control method usually adopts an independent constant power control strategy, that is, the shaft generator only focuses on the stability of its own output power, while the main propulsion diesel engine speed regulating device independently maintains the main propulsion diesel engine speed. This separate control is prone to cause negative interaction between the two systems in severe sea conditions, for example, the shaft generator increases the electromagnetic braking torque to maintain constant power, which further aggravates the decline of the main propulsion diesel engine speed, and even may cause the main propulsion diesel engine to stop.

[0037] As an embodiment of the present application, based on the operating state parameters and the ship environment parameters, the step of predicting the influence of the shaft generator adjustment action on the main propulsion diesel engine speed and the influence of the main propulsion diesel engine speed regulating device adjustment action on the shaft generator output power to obtain the interactive prediction result comprises:

[0038] monitoring the actual responses of the main propulsion diesel engine fuel injection quantity and the main propulsion diesel engine output torque, and the actual responses of the shaft generator excitation current and the shaft generator electromagnetic braking torque in real time;

[0039] It should be noted that the real-time monitoring of the actual responses of the main propulsion diesel engine fuel injection quantity and the main propulsion diesel engine output torque refers to obtaining the fuel injection quantity data of the main propulsion diesel engine under the current working condition through sensors installed on the main propulsion diesel engine, such as fuel flow meters and torque sensors, and synchronously measuring the actual output torque generated thereby. Similarly, the actual responses of the shaft generator excitation current and the shaft generator electromagnetic braking torque refer to monitoring the excitation current of the shaft generator through a current sensor and measuring the electromagnetic braking torque generated thereby through a torque sensor or a power measuring device. These actual response data are used to reflect the real-time dynamic behavior of the system.

[0040] According to the actual responses of the main propulsion diesel engine fuel injection quantity and the main propulsion diesel engine output torque, and the actual responses of the shaft generator excitation current and the shaft generator electromagnetic braking torque, evaluating the instantaneous deviations of the main propulsion diesel engine fuel torque parameters and the shaft generator excitation torque parameters used for prediction;

[0041] It should be noted that the main propulsion diesel engine fuel torque parameters and the shaft generator excitation torque parameters are key parameters in the prediction model for describing the relationship between the diesel engine output torque and the fuel injection quantity, and the relationship between the generator electromagnetic braking torque and the excitation current. Evaluating the instantaneous deviations refers to comparing the actual responses monitored in real time with the theoretical responses calculated based on the current fuel torque parameters and excitation torque parameters, so as to quantify the difference between them. For example, the deviation can be obtained by calculating the difference between the actual torque and the model predicted torque.

[0042] When the instantaneous deviation continuously exceeds the preset threshold, adjusting the fuel torque parameters and the excitation torque parameters according to the instantaneous deviation;

[0043] It should be noted that in actual application, when the instantaneous deviation continuously exceeds the preset threshold, it indicates that the parameters in the prediction model may no longer accurately reflect the actual situation of the system. At this time, the fuel torque parameters and the excitation torque parameters are adjusted according to the instantaneous deviation, for example, online parameter identification methods such as adaptive algorithm, Kalman filter or least squares method can be used to real-time correct these parameters, so that they are closer to the real dynamics of the system. The purpose is to ensure that the prediction model can dynamically adapt to the changes of the system and improve the accuracy of prediction. Therefore, according to the adjusted fuel torque parameters and excitation torque parameters, the operating state parameters and the ship environment parameters, the prediction can obtain more accurate interactive prediction results.

[0044] According to the adjusted fuel torque parameter and the excitation torque parameter, the operating state parameter and the ship environment parameter, the influence of the shaft generator adjustment action on the main propulsion diesel engine speed and the influence of the main propulsion diesel engine speed regulation device adjustment action on the shaft generator output power are predicted, and an interactive prediction result is obtained.

[0045] The scheme of the present application solves the problem of inaccurate prediction caused by the mismatch between the model parameters and the actual system in the traditional prediction method by introducing a real-time monitoring of the key system response and an adaptive adjustment mechanism of the parameters. Specifically, by continuously monitoring the actual response of the fuel injection amount and the output torque of the main propulsion diesel engine, and the actual response of the excitation current and the electromagnetic braking torque of the shaft generator, the system can obtain the real dynamic characteristics of the diesel engine and the generator under the current working condition. When there is a persistent deviation between these actual responses and the theoretical responses calculated by the prediction model based on existing parameters, which exceeds the preset threshold, it indicates that the fuel torque parameter and the excitation torque parameter in the prediction model may have deviated from the actual value. At this time, the system will adjust the corresponding parameters online according to these instantaneous deviations, so that the prediction model can dynamically adapt to the system characteristic drift caused by factors such as equipment aging and environmental changes. It is precisely because of this real-time parameter correction that the subsequent prediction process can be based on more accurate model parameters, thereby significantly improving the prediction accuracy of the influence of the shaft generator adjustment action on the main propulsion diesel engine speed and the prediction accuracy of the influence of the main propulsion diesel engine speed regulation device adjustment action on the shaft generator output power, providing a more reliable basis for joint decision-making.

[0046] Through the above technical scheme, the present application can effectively overcome the problem of inaccurate prediction caused by changes in system dynamic characteristics. Real-time monitoring and adaptive adjustment of key parameters ensure the accuracy and reliability of the prediction results, so that the subsequent joint decision-making can generate more accurate adjustment instructions, and more effectively eliminate the negative interaction between the shaft generator and the main propulsion diesel engine. This not only improves the operation stability of the ship propulsion and power generation system, reduces the risk of system oscillation or power fluctuation caused by misjudgment, but also enhances the adaptability and robustness of the system under complex and variable working conditions, thereby improving the overall operation efficiency and safety of the ship.

[0047] As an embodiment of the present application, according to the interactive prediction result, the steps of joint decision-making and generating the first adjustment instruction for adjusting the shaft generator and the second adjustment instruction for adjusting the main propulsion diesel engine speed regulation device include:

[0048] Obtaining operation signals related to the main propulsion diesel engine speed setting or fuel adjustment; specifically, the system receives real-time instructions from the bridge or engine room control panel, such as the target speed set by the crew manually, the adjustment instructions of the fuel pump, the load distribution instructions, etc. These operation signals reflect the crew's expectations for the current running state or future running trend of the ship.

[0049] According to the operation signal, identify the crew's operation intention; it can be understood as analyzing and judging the obtained operation signal to determine the crew's current hope for the system to achieve the target, such as prioritizing speed stability, prioritizing power output, prioritizing fuel economy optimization, or responding to emergency situations, etc. This can be achieved through a pre-set rule base, machine learning model or expert system.

[0050] According to the crew's operation intention, dynamically adjust the priority of the optimization target of the joint decision; specifically, according to the identified crew's intention, different optimization targets (such as speed stability, power output constancy, fuel efficiency, system safety, etc.) in the joint decision algorithm are given different weights or priorities. For example, when the crew issues an emergency acceleration instruction, the speed stability may be given the highest priority, and when the crew performs routine cruising operations, fuel economy may become a more important optimization target.

[0051] Based on the adjusted optimization target priority and the interactive prediction result, jointly decide and calculate the first adjustment instruction and the second adjustment instruction; specifically, after considering the real-time operation intention of the crew and the corresponding optimization target priority, the system comprehensively utilizes the interactive prediction result, through a multi-objective optimization algorithm or a decision matrix, to calculate the first adjustment instruction of the shaft generator and the second adjustment instruction of the main propulsion diesel engine speed regulation device that best meets the current comprehensive demand.

[0052] The scheme of the present application effectively solves the problem that the traditional joint decision may be inconsistent with the actual operation intention of the crew by introducing the recognition of the operation intention of the crew and the dynamic adjustment of the priority of the optimization target. Specifically, when the system obtains the operation signal of the crew, it can timely recognize the intention of the crew, such as whether it is necessary to respond quickly, maintain stability, or perform energy-saving operation. Based on this intention, the system can dynamically adjust the priority of the optimization target in the joint decision process to ensure that the performance indicator currently most concerned by the crew can be prioritized when generating the first adjustment instruction and the second adjustment instruction. For example, when the crew needs to accelerate urgently, the system will give the highest priority to the quick response and stability of the main propulsion diesel engine speed, even if this may temporarily sacrifice the smoothness of part of the power output; while in normal navigation, fuel economy and the constancy of power output may be prioritized. This mechanism enables the system to be more flexible and intelligent in adapting to the actual operation demand of the ship and the operation habit of the crew, avoiding the efficiency decline or safety hazards caused by the conflict between the system autonomous decision and manual intervention.

[0053] Through the above technical scheme, the present application can significantly improve the intelligent level and human-machine cooperation efficiency of the constant power speed control system of the ship shaft generator. Instead of simply making decisions according to preset logic, the system can actively perceive and respond to the real-time operation intention of the crew, thereby generating adjustment instructions that are more in line with the actual operation demand. This not only effectively avoids control conflicts or operation delays caused by inconsistency between the system and the crew's intention, but also maximizes the energy-saving potential of the shaft generator while ensuring the stability and safety of the system, thereby improving the overall operation efficiency and operation flexibility of the ship. Especially in complex and variable sea conditions or emergency operation scenarios, the scheme can ensure that the system decision is highly coordinated with the judgment of the crew, thereby significantly enhancing the maneuverability and safety of the ship.

[0054] As an embodiment of the present application, the step of sending the first adjustment instruction and the second adjustment instruction to the controller of the shaft generator and the speed regulating device of the main propulsion diesel engine respectively includes:

[0055] The generated first adjustment instruction and second adjustment instruction are subjected to safety verification; specifically, before the adjustment instructions are actually executed, a series of evaluations and verifications are performed to ensure that the instructions are safe, feasible and will not cause system abnormalities or failures under the current ship operation state and environmental conditions. Among them, the first adjustment instruction is an instruction for adjusting the output power or speed of the shaft generator, and the second adjustment instruction is an instruction for adjusting the speed or fuel injection amount of the main propulsion diesel engine. Safety verification may include but is not limited to checking whether the instruction parameters are within the preset safety range, whether they conflict with the current system state, and whether they may trigger a chain reaction to cause system instability, etc.

[0056] The first adjustment instruction and the second adjustment instruction that pass the safety check are sent to the controller of the shaft generator and the speed regulating device of the main propulsion diesel engine respectively to eliminate the negative interaction predicted; specifically, only when the adjustment instruction passes the safety check and is determined to be a safe and effective instruction, the adjustment instruction is allowed to be sent to the corresponding executing mechanism. The controller of the shaft generator is responsible for receiving and executing the first adjustment instruction to adjust the operating state of the shaft generator; and the speed regulating device of the main propulsion diesel engine is responsible for receiving and executing the second adjustment instruction to adjust the operating state of the main propulsion diesel engine. This mechanism ensures that only instructions that have been strictly reviewed can be adopted and executed by the system, thereby effectively avoiding potential risks.

[0057] The scheme of the present application effectively solves the potential safety hazards of the adjustment instruction in the basic scheme by introducing a safety check link before the instruction is sent. Specifically, after the joint decision module generates the first adjustment instruction and the second adjustment instruction, these instructions are not immediately sent for execution, but are first sent to the safety check module for evaluation. The safety check module will comprehensively judge the rationality and safety of the instruction according to the pre-set safety rules, the limitations of the system operating parameters and the environmental conditions of the ship, etc. For example, if a certain instruction may cause the main propulsion diesel engine to rotate at too low a speed or overload the output power of the shaft generator, the instruction will be identified as an unsafe instruction. Only when the instruction is determined to pass the safety check, i.e. the instruction parameters are within all safety threshold ranges and will not cause system abnormalities, the instruction is allowed to be sent to the controller of the shaft generator and the speed regulating device of the main propulsion diesel engine. Thus, the present scheme avoids the execution of unsafe or unreasonable adjustment instructions from the source, thereby ensuring the stable operation of the ship propulsion and power generation system and the safety of the equipment.

[0058] Through the above technical scheme, the safety and reliability of the ship shaft generator constant power speed control system are significantly improved. By strictly checking the safety of the adjustment instruction, potential risks caused by decision-making errors, environmental mutations or system failures, etc. can be effectively avoided, and unreasonable or dangerous instructions can be prevented from being executed, thereby avoiding equipment damage, system collapse or sailing accidents. This enables the entire control system to operate more stably and reliably in complex and variable marine environments, providing a solid guarantee for the safe sailing of the ship.

[0059] As an embodiment of the present application, the step of safety checking the generated first adjustment instruction and the second adjustment instruction comprises:

[0060] Obtaining the disturbance intensity of the environment in which the ship is currently located;

[0061] Obtaining the margin between the key operating parameters of the propulsion system and the respective absolute safety limits;

[0062] According to the disturbance intensity and the margin, the dynamic safety threshold of each key operating parameter is calculated;

[0063] The generated instruction parameters corresponding to the first adjustment instruction and the second adjustment instruction are compared with the dynamic safety threshold, and the safety of the adjustment instruction is judged according to the comparison result.

[0064] Specifically, the disturbance intensity of the current environment of the ship refers to real-time monitoring and quantifying external environmental factors affecting the operation of the ship, such as sea conditions (wave height, period), wind speed, wind direction, water flow speed, etc. These disturbance intensity parameters can be obtained through ship-borne sensors, meteorological navigation systems or external data sources, and the purpose is to provide real-time risk assessment basis for external environment for safety verification. Among them, the margin between the key operating parameters of the propulsion system and the respective absolute safety limit value refers to continuously monitoring the current value of the key operating parameters such as the speed of the main propulsion diesel engine, the output power of the shaft generator, the torque of the propulsion shaft, the fuel consumption rate, the exhaust temperature, and the lubricating oil pressure, and comparing it with the pre-set absolute safety upper and lower limits specified by the equipment manufacturer or the ship classification society, so as to calculate the remaining space of each parameter from its safety boundary. The size of the margin reflects the safety of the current operating state of the system, and the purpose is to evaluate the carrying capacity and risk bearing capacity of the system. In practical application, according to the disturbance intensity and the margin, the dynamic safety threshold of each key operating parameter is calculated, which means that the severity of the external environment and the health status of the system are considered comprehensively, and the safety verification threshold of each key operating parameter is dynamically adjusted through a pre-set algorithm or model. For example, when the disturbance intensity is large (such as encountering severe sea conditions) and the system margin is small (such as the speed of the main propulsion diesel engine approaching the upper limit), the dynamic safety threshold will be tightened to ensure the safe operation of the system in extreme conditions; on the contrary, when the disturbance intensity is small and the system margin is sufficient, the dynamic safety threshold can be appropriately relaxed to allow the system to perform better within the safety range.

[0065] The scheme of the present application introduces disturbance intensity and key operating parameter margin, and dynamically calculates safety threshold based on this, so that the safety of the adjustment instruction is no longer dependent on fixed, static threshold. It is precisely because of this dynamic adaptability that the system can adjust the strictness of safety verification in real time according to the changes of the actual operating environment of the ship and its own state. When the external environment is severe or the system internal margin is insufficient, the safety threshold will be automatically tightened, so as to identify potential risks earlier and more sensitively, and prevent the adjustment instruction from pushing the system to an unsafe area. On the contrary, when the environment is good and the system margin is sufficient, the safety threshold will be appropriately relaxed to avoid unnecessary restrictions, so as to allow the system to achieve better performance and efficiency under the premise of safety.

[0066] As an embodiment of the present application, the step of calculating the dynamic safety threshold of each key operating parameter according to the disturbance intensity and the margin comprises:

[0067] Determining the influence factor of the disturbance intensity on the safety threshold of each key operating parameter; specifically, it refers to quantifying the influence degree of external environmental disturbance (such as wind and wave, current, etc.) on the safety margin of the key operating parameters (such as the speed of the main propulsion diesel engine, the output power of the shaft generator, the torque of the propulsion shaft, etc.) of the ship propulsion and power generation system. The influence factor can be a weight coefficient, a functional relationship or a lookup table, and its purpose is to reflect the change in sensitivity of the system to the safety threshold under different disturbance intensities. For example, when the disturbance intensity is high, the system may need a smaller safety margin to maintain stable operation, or a more stringent safety threshold to avoid instability.

[0068] Determining the influence factor of the key operating parameter margin on its own safety threshold; it can be understood as evaluating the margin size between the current key operating parameter and its absolute safety limit, and the influence on the setting of the dynamic safety threshold of the parameter itself. The influence factor can also be a weight, a function or a mapping relationship, and its purpose is to ensure that when the system operating margin is sufficient, the dynamic safety threshold can be appropriately relaxed to improve operating efficiency; and when the margin is small, the dynamic safety threshold needs to be tightened to enhance safety.

[0069] According to the disturbance intensity, the margin, the influence factor of the disturbance intensity on the safety threshold of each key operating parameter, and the influence factor of the key operating parameter margin on its own safety threshold, the disturbance intensity and the margin are fused and calculated to obtain the dynamic safety threshold of each key operating parameter. Fusion calculation refers to the comprehensive processing of the above two influence factors and the disturbance intensity and the margin itself to generate a more accurate and adaptive dynamic safety threshold. This fusion calculation can use various mathematical models or algorithms, such as weighted average, nonlinear mapping, fuzzy logic reasoning or machine learning model, etc., and its purpose is to more comprehensively consider the influence of various factors on the safety threshold, thereby improving the accuracy and reliability of safety checking.

[0070] The scheme of the present application solves the problems of insufficient precision and poor adaptability in dynamic safety threshold calculation of the traditional method by introducing the influence factor of disturbance intensity on the safety threshold of each key operating parameter and the influence factor of key operating parameter margin on its own safety threshold, and fusing and calculating these factors. Specifically, by determining the disturbance intensity influence factor, the system can identify and quantify the potential threat of external environmental changes to the safety margin, so that the safety threshold can be dynamically adjusted according to the actual environmental conditions, avoiding safety risks caused by improper threshold setting in harsh environments. At the same time, by determining the key operating parameter margin influence factor, the system can make full use of the margin information of the current operating state, allowing a larger operating space when the margin is sufficient, improving the operating efficiency; when the margin is tight, the threshold is tightened in time to enhance system protection. Finally, through the fusion calculation of disturbance intensity and margin and their respective influence factors, the fine and adaptive management of dynamic safety threshold is realized, making the safety checking process more intelligent and robust.

[0071] Through the above technical scheme, the present application can more accurately and adaptively calculate the dynamic safety threshold of each key operating parameter. This not only significantly improves the precision and reliability of the safety check of the regulation instruction, effectively avoiding false positives or false negatives caused by unreasonable threshold setting, but also enables the ship propulsion and power generation system to ensure operation safety and maximize system performance in complex and variable sea conditions, improving the overall operating efficiency and economy of the ship.

[0072] As an embodiment of the present application, the step of fusing and calculating the disturbance intensity and the margin includes:

[0073] According to the disturbance intensity, the margin, the influence factor of disturbance intensity on the safety threshold of each key operating parameter, and the influence factor of key operating parameter margin on its own safety threshold, the dynamic safety threshold of each key operating parameter is calculated through nonlinear mapping or piecewise function relationship.

[0074] wherein the "non-linear mapping" refers to the process of converting input variables (e.g. disturbance intensity, margin, and their influencing factors) into output variables (i.e. dynamic safety threshold) through non-linear function relationships. This mapping relationship can better capture the complex, non-linear interactions between parameters in the actual system. For example, when the disturbance intensity is small, its impact on the safety threshold may not be significant, but when the disturbance intensity reaches a certain level, its impact will increase sharply. Common non-linear mapping functions include but are not limited to Sigmoid function, ReLU function, exponential function, logarithmic function, etc. The "piecewise function relationship" refers to dividing the entire value range of the input variable into several subintervals, and defining different function relationships in each subinterval to calculate the dynamic safety threshold. For example, when the disturbance intensity is at different levels such as low, medium, and high, different linear or non-linear functions can be used to calculate the dynamic safety threshold. The advantage of this approach is that it can flexibly adjust the calculation logic according to different operating conditions or environmental conditions, to more accurately reflect the actual safety requirements.

[0075] The scheme of the present application can more accurately and precisely depict the dynamic safety boundary of the ship propulsion and power generation system under complex and variable environments by introducing non-linear mapping or piecewise function relationship for the fusion calculation of disturbance intensity and margin. The traditional linear superposition or simple weighting method may not fully reflect the complex coupling relationship between factors in the actual system, resulting in overly conservative or overly aggressive safety threshold settings. Through non-linear mapping, the sensitivity differences of the system to disturbances and margins under different operating states can be simulated, for example, when the system is close to the limit operating condition, a small disturbance may cause a huge safety risk, and the non-linear mapping can capture this asymmetry. Piecewise function allows the use of the most suitable calculation model in different operating intervals, thereby maximizing the system's operating efficiency and robustness while ensuring safety.

[0076] As an embodiment of the present application, the step of determining the influencing factor of disturbance intensity on the safety threshold of each key operating parameter includes:

[0077] Collecting historical data of key operating parameters such as main propulsion diesel engine speed, shaft generator output power, and propulsion shaft torque under different disturbance intensities, as well as corresponding safety event records;

[0078] Conducting correlation analysis on the historical data and safety event records to identify the degree of deviation of each key operating parameter from its safety range or the frequency of safety events under different disturbance intensities;

[0079] According to the degree of deviation of each key operating parameter from its safety range or the frequency of safety events, quantifying the weight of disturbance intensity on the safety threshold of each key operating parameter, thereby determining the influencing factor of disturbance intensity on the safety threshold of each key operating parameter.

[0080] wherein "disturbance intensity" refers to the severity of external environmental factors affecting the operation of the ship propulsion power generation system, such as sea state (including wind speed, wave height, swell period, etc.), ship motion state (such as the amplitude and frequency of roll, pitch, and yaw), and load surges, etc. "Key operating parameters" refer to parameters that are critical to the safe operation of the ship and the performance of the system, such as the speed of the main propulsion diesel engine, the output power of the shaft generator, the torque of the propulsion shafting, etc. "Historical data" refers to the record of the changes in these key operating parameters over time under different disturbance intensities. "Safety event records" refer to the records of abnormal or dangerous events such as overloading, overspeed, instability, shutdown, etc. that have occurred in the system under certain disturbance intensities. Further, "correlation analysis" can be achieved using statistical methods (such as regression analysis, correlation analysis) or machine learning algorithms (such as clustering analysis, classification algorithms), with the purpose of discovering the internal relationship between the disturbance intensity and the degree of deviation of the key operating parameters from their safe range or the frequency of safety events. The "degree of deviation from its safe range" can be quantified as the amplitude, duration, or frequency of parameter values exceeding the pre-set safety interval. The "frequency of safety events" refers to the number or probability of occurrence of a specific safety event within a certain range of disturbance intensity. Thus, according to the degree of deviation or the frequency of occurrence, the influence weight of the disturbance intensity on the safety threshold of each key operating parameter can be quantified. For example, when the disturbance intensity is high, if the historical data shows that the key operating parameters are more likely to deviate significantly from their safe range or the frequency of safety events increases significantly, then a greater influence weight can be assigned to this disturbance intensity. This influence weight is the "influence factor of disturbance intensity on the safety threshold of each key operating parameter", which reflects the degree to which the safety threshold needs to be adjusted under different disturbance intensities.

[0081] The scheme of the present application can objectively and quantitatively evaluate the influence of different disturbance intensities on the safety of key operating parameters of the ship propulsion power generation system by collecting and analyzing a large amount of historical operating data and safety event records. By correlating the disturbance intensity with the degree of parameter deviation or the frequency of safety events, it can be identified under which disturbance conditions the system is more likely to face safety risks. Based on this empirical data-driven method, the actual influence of disturbance intensity on the safety threshold can be converted into a calculable influence factor, thereby providing accurate input for the subsequent calculation of dynamic safety threshold.

[0082] By the technical solution, the sensitivity evaluation of the system to the disturbance intensity is more accurate and reliable. The quantitative method based on the historical data and the safety event records avoids the limitation of setting the safety threshold value only by experience or fixed parameters, so that the safety threshold value can more truly reflect the safety margin requirement under the current environment. Thus, during the actual operation of the ship, the system can adaptively adjust the safety threshold value according to the real-time disturbance intensity, so as to optimize the operation strategy of the shaft generator under the premise of ensuring the safety of the ship operation, and improve the energy utilization efficiency and the system stability.

[0083] As an embodiment of the present application, the step of determining the influence factor of the key operating parameter margin on the self safety threshold value comprises:

[0084] The historical data of the key operating parameters under different margin levels and the safety event records are collected; specifically, the system continuously monitors and stores the real-time values of the key operating parameters of the ship propulsion and power generation system under different operating conditions, such as different loads, different sea conditions, different speeds, etc., such as the main propulsion diesel engine speed, the shaft generator output power, the propulsion shaft torque, and the margin information between these parameters and their respective absolute safety limits. At the same time, the system also records safety events related to these operating parameters, such as overspeed alarm, overload trip, abnormal vibration, etc., and records the margin level when these events occur. These data can come from the ship's voyage data recorder, distributed control system or special data acquisition system.

[0085] The historical data and the safety event records are analyzed to identify the degree of deviation of each key operating parameter from its safety range or the frequency of safety events under different margin levels; it can be understood that the collected historical data is analyzed by using statistical methods, machine learning algorithms or data mining techniques. For example, the duration, amplitude of the key operating parameters (such as the main propulsion diesel engine speed) exceeding their normal working range, or the probability of safety events (such as overspeed alarm) occurring in different margin intervals can be calculated. The purpose is to reveal the internal relationship between the margin size and the system safety risk.

[0086] The preset expert experience rule is combined to correct or supplement the deviation degree or the frequency of safety events. Specifically, on the basis of data analysis, the professional knowledge and experience of a ship design expert, a chief engineer or a senior engineer are introduced. For example, even if no safety event occurs at a certain margin level in historical data, but according to the expert experience, the margin level still has potential risks in a specific extreme working condition, and the risk assessment at the margin level can be adjusted upward. Conversely, if the data analysis result shows that a certain margin level is at high risk, but the expert believes that this may be caused by an occasional factor, and can be avoided by other means in actual operation, the risk assessment can be appropriately adjusted downward. The purpose is to make up for the possible deficiencies of historical data and improve the comprehensiveness and accuracy of risk assessment.

[0087] According to the correction or supplement result, the weight of the margin on the safety threshold of itself is quantified, so as to determine the influence factor of the margin of the key operating parameter on the safety threshold of itself. Specifically, the deviation degree or the frequency after being corrected or supplemented by the expert experience is converted into a quantitative influence factor through a mathematical model or a mapping function. For example, it can be set that the smaller the margin, the greater the degree of deviation from the safety range or the higher the frequency of safety events, and the corresponding influence factor is greater, indicating that the influence of the margin on the safety threshold of itself is more significant. The influence factor can be a value between 0 and 1, which is used to adjust the weight of the margin in the subsequent fusion calculation of the dynamic safety threshold.

[0088] The scheme of the present application can objectively identify the correlation between the margin and the safety risk by systematically collecting and analyzing the historical data of the key operating parameters and the safety event records at different margin levels. Through correlation analysis of these data, the degree of deviation of the key operating parameter from the safety range or the frequency of safety events at different margin levels can be quantified, thereby providing data support for the influence of the margin on the safety threshold of itself. Further, the data analysis result is corrected or supplemented in combination with the preset expert experience rule, which effectively makes up for the limitations of the pure data-driven method, such as data sparseness or unconsidered extreme working conditions, so that the risk assessment is more comprehensive and accurate. Finally, based on the corrected or supplemented result, the weight of the margin on the safety threshold of itself is quantified, so as to determine the more accurate and reliable influence factor of the margin of the key operating parameter on the safety threshold of itself. It is this combination of data-driven and expert experience that makes the determined influence factor more truly reflect the potential influence of the margin change on the system safety, and provides a solid foundation for the subsequent calculation of the dynamic safety threshold.

[0089] The above technical solution overcomes the empirical or static problems that may exist in traditional methods when determining the influence factors of key operating parameter margins on their own safety thresholds. This application, by introducing historical data analysis and expert experience correction, makes the determined influence factors more accurate and adaptable, and can more precisely reflect the actual risks faced by the system under different margin levels. Therefore, when calculating dynamic safety thresholds, the safety of key operating parameters can be assessed more accurately, thereby improving the reliability of safety verification and ensuring that the constant power speed control system of the ship's shaft generator can make more reasonable and safer adjustment decisions under various operating conditions, effectively avoiding potential safety risks caused by inaccurate margin assessments.

[0090] like Figure 2 The diagram illustrates a constant power speed control system for a ship shaft-driven generator. The system includes:

[0091] The parameter acquisition module 201 is used to acquire the operating status parameters of the ship propulsion power generation system and the ship environmental parameters.

[0092] The interactive prediction module 202 is used to predict the impact of the shaft generator adjustment action on the main propulsion diesel engine speed, and the impact of the main propulsion diesel engine speed governor adjustment action on the output power of the shaft generator based on the operating status parameters and ship environmental parameters, and obtain interactive prediction results.

[0093] The joint decision-making module 203 is used to make joint decisions and generate a first adjustment command for adjusting the shaft-driven generator and a second adjustment command for adjusting the speed control device of the main propulsion diesel engine based on the interactive prediction results.

[0094] The instruction sending module 204 is used to send the first adjustment instruction and the second adjustment instruction to the controller of the shaft-driven generator and the speed control device of the main propulsion diesel engine, respectively, to eliminate the anticipated negative interaction.

[0095] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A constant power speed control method for a marine shaft generator, characterized by, The method comprises the following steps: Obtain the operating state parameters of the ship propulsion power generation system and the ship environment parameters; Based on the operating state parameters and the ship environment parameters, predict the influence of the shaft generator adjustment action on the main propulsion diesel engine speed and the influence of the main propulsion diesel engine speed regulation device adjustment action on the shaft generator output power, and obtain the interactive prediction result, which comprises the following steps: Real-time monitoring of the actual response of the main propulsion diesel engine fuel injection quantity and the main propulsion diesel engine output torque, and the actual response of the shaft generator excitation current and the shaft generator electromagnetic braking torque; According to the actual response of the main propulsion diesel engine fuel injection quantity and the main propulsion diesel engine output torque, and the actual response of the shaft generator excitation current and the shaft generator electromagnetic braking torque, evaluate the instantaneous deviation of the main propulsion diesel engine fuel torque parameter and the shaft generator excitation torque parameter used for prediction; When the instantaneous deviation continuously exceeds the preset threshold, adjust the fuel torque parameter and the excitation torque parameter according to the instantaneous deviation; According to the adjusted fuel torque parameter and excitation torque parameter, the operating state parameters and the ship environment parameters, predict the influence of the shaft generator adjustment action on the main propulsion diesel engine speed and the influence of the main propulsion diesel engine speed regulation device adjustment action on the shaft generator output power, and obtain the interactive prediction result; According to the interactive prediction result, jointly decide and generate the first adjustment instruction for adjusting the shaft generator and the second adjustment instruction for adjusting the main propulsion diesel engine speed regulation device, which comprises the following steps: Obtain the operation signal related to the main propulsion diesel engine speed setting or fuel adjustment; According to the operation signal, identify the crew operation intention; According to the crew operation intention, dynamically adjust the optimization target priority of joint decision; Based on the adjusted optimization target priority and the interactive prediction result, jointly decide and calculate to generate the first adjustment instruction and the second adjustment instruction; Send the first adjustment instruction and the second adjustment instruction to the controller of the shaft generator and the main propulsion diesel engine speed regulation device respectively to eliminate the negative interaction predicted.

2. A constant power speed control method for a marine shaft generator as defined in claim 1, characterized by The step of sending the first adjustment instruction and the second adjustment instruction to the controller of the shaft generator and the main propulsion diesel engine speed regulation device respectively comprises: Safety check on the generated first adjustment instruction and second adjustment instruction; Send the first adjustment instruction and second adjustment instruction that pass the safety check to the controller of the shaft generator and the main propulsion diesel engine speed regulation device respectively to eliminate the negative interaction predicted.

3. A constant power speed control method for a marine shaft generator as defined in claim 2, characterized in that, The step of safety checking on the generated first adjustment instruction and second adjustment instruction comprises: Obtain the disturbance intensity of the current environment of the ship; Obtain the margin between the key operating parameters of the propulsion system and their absolute safety limits; According to the disturbance intensity and the margin, calculate the dynamic safety threshold of each key operating parameter; Compare the instruction parameters corresponding to the generated first adjustment instruction and second adjustment instruction with the dynamic safety threshold, and judge the safety of the adjustment instruction according to the comparison result.

4. A constant power speed control method for a marine shaft generator as defined in claim 3, characterized in that, The step of calculating the dynamic safety threshold of each key operating parameter according to the disturbance intensity and the margin comprises: determining an influence factor of the disturbance intensity on the safety threshold of each key operating parameter; determining an influence factor of the margin of the key operating parameter on the safety threshold of the key operating parameter; fusing the disturbance intensity and the margin according to the disturbance intensity, the margin, the influence factor of the disturbance intensity on the safety threshold of each key operating parameter, and the influence factor of the margin of the key operating parameter on the safety threshold of the key operating parameter, to obtain the dynamic safety threshold of each key operating parameter.

5. A constant power speed control method for a marine shaft generator as defined in claim 4, characterized in that, The step of fusing the disturbance intensity and the margin comprises: calculating the dynamic safety threshold of each key operating parameter through a nonlinear mapping or a segmented function relationship according to the disturbance intensity, the margin, the influence factor of the disturbance intensity on the safety threshold of each key operating parameter, and the influence factor of the margin of the key operating parameter on the safety threshold of the key operating parameter.

6. A constant power speed control method for a marine shaft generator as defined in claim 4, characterized by The step of determining the influence factor of the disturbance intensity on the safety threshold of each key operating parameter comprises: collecting historical data of the main propulsion diesel engine speed, the shaft generator output power, and the propulsion shaft torque under different disturbance intensities, and corresponding safety event records; performing correlation analysis on the historical data and the safety event records to identify the degree of deviation of each key operating parameter from its safety range or the frequency of safety events under different disturbance intensities; quantifying the action weight of the disturbance intensity on the safety threshold of each key operating parameter according to the degree of deviation of each key operating parameter from its safety range or the frequency of safety events, to determine the influence factor of the disturbance intensity on the safety threshold of each key operating parameter.

7. A constant power speed control method for a marine shaft generator as defined in claim 4, wherein The step of determining the influence factor of the margin of the key operating parameter on the safety threshold of the key operating parameter comprises: collecting historical data of the key operating parameter and safety event records under different margin levels; performing correlation analysis on the historical data and the safety event records to identify the degree of deviation of each key operating parameter from its safety range or the frequency of safety events under different margin levels; combining pre-set expert experience rules to correct or supplement the degree of deviation or the frequency of safety events; quantifying the action weight of the margin on the safety threshold of the key operating parameter according to the correction or supplement results, to determine the influence factor of the margin of the key operating parameter on the safety threshold of the key operating parameter.

8. A constant power speed control system for a marine shaft generator, characterized by, The constant power speed control method of the ship shaft generator according to any one of claims 1-7, the system comprises: a parameter acquisition module configured to acquire operating state parameters of the ship propulsion and power generation system and ship environment parameters; an interactive prediction module configured to predict, based on the operating state parameters and the ship environment parameters, an influence of a shaft generator adjustment action on the main propulsion diesel engine speed and an influence of a main propulsion diesel engine speed adjustment action on the shaft generator output power, to obtain an interactive prediction result; a joint decision module configured to jointly decide and generate a first adjustment instruction for adjusting the shaft generator and a second adjustment instruction for adjusting the main propulsion diesel engine speed adjustment device according to the interactive prediction result; The instruction sending module is configured to send the first adjustment instruction and the second adjustment instruction to a controller of the shaft generator and a speed regulating device of the main propulsion diesel engine, respectively, so as to eliminate the negative interaction predicted.

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