Variable frequency control method and device for ship cooling system

Abstract

This application discloses a variable frequency control method, device, electronic equipment, and storage medium for a ship's cooling system. The technical solution provided in this application involves, when the ship is in navigation mode, collecting the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the secondary cooler. Based on the first freshwater temperature, the number of seawater pumps activated and their operating speed are controlled, and based on the second freshwater temperature, the opening degree of the control valve corresponding to the secondary cooler is controlled. When the ship is in moored mode, the main cooler is shut down, and the third freshwater temperature of the designated secondary cooler's freshwater cooling subsystem is collected. Based on the third freshwater temperature, the number of seawater pumps activated and their operating speed are controlled, and the control valve corresponding to the designated secondary cooler is controlled to its maximum opening degree. Using the above technical means, precise distribution of seawater flow to multiple freshwater cooling systems can be achieved, thereby avoiding energy waste.

Description

Technical Field

[0001] This application relates to the field of marine technology, and in particular to a variable frequency control method, device, electronic equipment and storage medium for a marine cooling system. Background Technology

[0002] Currently, during ship operation, the power plant and other equipment generate a large amount of waste heat, requiring a highly efficient cooling system to dissipate this heat and ensure the normal operating temperature of critical equipment such as main engines, auxiliary engines, and generators. Ship cooling systems typically employ a central cooling system, consisting of a freshwater cooling system and a seawater system. Low-temperature freshwater flows through the equipment requiring cooling (such as main engine cylinder liner water and generator coolers) to absorb heat, then enters the central cooler, where it transfers the heat to the low-temperature seawater, which ultimately carries the heat overboard. Generally, the cooling water system uses fixed-frequency pumps (seawater pumps or freshwater pumps) to drive the cooling water circulation. Under this control method, the pumps always operate at their rated speed to perform the cooling operation.

[0003] However, for ship cooling systems using multiple freshwater cooling systems, simply controlling the pump speed at a fixed frequency cannot accurately regulate the cooling water temperature, potentially leading to overcooling at low loads or insufficient cooling during sudden load changes. Furthermore, the heat dissipation requirements of equipment cooled by different freshwater systems vary under different operating conditions. Continuously operating a fixed-frequency pump at full load in such cases could consume a large amount of unnecessary electrical energy, resulting in significant energy waste. Summary of the Invention

[0004] This application provides a variable frequency control method, device, electronic equipment, and storage medium for a ship cooling system, which can perform precise variable frequency control on the seawater pump of the ship cooling system, realize accurate distribution of seawater flow in multiple freshwater cooling systems, and solve the technical problem of inaccurate distribution in ship cooling systems.

[0005] In a first aspect, embodiments of this application provide a variable frequency control method for a ship cooling system. The ship cooling system includes a variable frequency controller, a seawater subsystem, multiple freshwater cooling subsystems, and multiple corresponding central coolers. The seawater subsystem is connected to each of the central coolers via seawater circulation pipes, and each of the freshwater cooling subsystems is connected to a corresponding central cooler via freshwater circulation pipes. The central cooler is used for heat exchange between seawater in the seawater circulation pipes and freshwater in the freshwater circulation pipes to perform equipment cooling operations. The central cooler includes a main cooler and several secondary coolers. The seawater circulation pipes are equipped with a seawater pump and control valves corresponding to each of the secondary coolers. The seawater pump is used to control the total inlet flow rate of the seawater subsystem, and the control valves are used to control the inlet flow rate of the corresponding secondary coolers. Each freshwater cooling subsystem's corresponding freshwater circulation pipe is equipped with a temperature sensor for real-time detection of the freshwater temperature in the corresponding freshwater circulation pipe. The variable frequency controller is signal-connected to the seawater pump, the control valves, and the temperature sensor. The frequency conversion control method for the ship cooling system includes: When the ship is in navigation mode, the frequency converter collects the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the slave cooler. Based on the first freshwater temperature, the number of seawater pumps turned on and the operating speed are controlled, and based on the second freshwater temperature, the opening degree of the control valve of the corresponding slave cooler is controlled. When the ship is in berthing mode, the main cooler is shut down. Based on the third freshwater temperature of the freshwater cooling subsystem corresponding to the designated slave cooler collected by the frequency converter, the number of seawater pumps turned on and the operating speed are controlled based on the third freshwater temperature, and the control valve corresponding to the designated slave cooler is controlled to the maximum opening degree.

[0006] Furthermore, the control of the number of seawater pumps activated and their operating speed based on the first freshwater temperature includes: If multiple seawater pumps are turned on, and a designated seawater pump is operating at its lowest speed and the temperature of the first freshwater is lower than a first set threshold, the designated seawater pump is turned off. If the temperature of the first freshwater is higher than a second preset threshold when one of the seawater pumps is turned on, the number of seawater pumps turned on will be increased.

[0007] Furthermore, increasing the number of seawater pumps that are turned on includes: Based on the cumulative running time of each of the currently inactive seawater pumps, select the seawater pump with the shortest cumulative running time to start.

[0008] Furthermore, the control of the number of seawater pumps activated and their operating speed based on the third freshwater temperature includes: If multiple seawater pumps are turned on, and a designated seawater pump is operating at its lowest speed and the temperature of the third freshwater is lower than a first set threshold, the designated seawater pump is turned off. If the temperature of the third freshwater is higher than the second set threshold when one of the seawater pumps is turned on, the number of seawater pumps turned on will be increased.

[0009] Further, the opening degree of the control valve of the cooler corresponding to the second freshwater temperature control includes: The opening degree of the control valve of the cooler is dynamically adjusted based on the PID algorithm so that the temperature of the second fresh water is within the set temperature range.

[0010] Furthermore, the method also includes: In the set operating mode, the seawater pump is controlled to run at full load, and the control valve is set to the maximum opening degree.

[0011] Furthermore, the method also includes: The ship's operating condition signal is detected, and the navigation mode and the berthing mode are switched based on the ship's operating condition signal.

[0012] In a second aspect, embodiments of this application provide a variable frequency control device for a ship cooling system. The ship cooling system includes a variable frequency controller, a seawater subsystem, multiple freshwater cooling subsystems, and multiple corresponding central coolers. The seawater subsystem is connected to each of the central coolers via seawater circulation pipes, and each of the freshwater cooling subsystems is connected to its corresponding central cooler via freshwater circulation pipes. The central cooler is used for heat exchange between seawater in the seawater circulation pipes and freshwater in the freshwater circulation pipes to perform equipment cooling operations. The central cooler includes a main cooler and several secondary coolers. The seawater circulation pipes are equipped with a seawater pump and control valves corresponding to each of the secondary coolers. The seawater pump is used to control the total inlet flow rate of the seawater subsystem, and the control valves are used to control the inlet flow rate of the corresponding secondary coolers. Each freshwater cooling subsystem's corresponding freshwater circulation pipe is equipped with a temperature sensor for real-time detection of the freshwater temperature in the corresponding freshwater circulation pipe. The variable frequency controller is signal-connected to the seawater pump, the control valves, and the temperature sensors. The frequency conversion control device of the ship cooling system includes: The navigation control module is used to, when the ship is in navigation mode, collect the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the slave cooler based on the frequency converter, control the number of seawater pumps to be turned on and the operating speed based on the first freshwater temperature, and control the opening degree of the control valve of the corresponding slave cooler based on the second freshwater temperature. The berthing control module is used to shut down the main cooler when the ship is in berthing mode, collect the third freshwater temperature of the freshwater cooling subsystem corresponding to the designated slave cooler based on the frequency converter, control the number of seawater pumps to be turned on and their operating speed based on the third freshwater temperature, and control the control valve corresponding to the designated slave cooler to the maximum opening degree.

[0013] In a third aspect, embodiments of this application provide an electronic device, including: Memory and one or more processors; The memory is used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the frequency conversion control method for the ship cooling system as described in the first aspect.

[0014] In a fourth aspect, embodiments of this application provide a storage medium containing computer-executable instructions, which, when executed by a computer processor, are used to perform the frequency conversion control method for a ship cooling system as described in the first aspect.

[0015] This embodiment of the application, when the ship is in sailing mode, uses a frequency converter to collect the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the secondary cooler. Based on the first freshwater temperature, it controls the number of seawater pumps activated and their operating speed, and based on the second freshwater temperature, it controls the opening of the control valve of the corresponding secondary cooler. When the ship is in moored mode, the main cooler is shut down, and the frequency converter collects the third freshwater temperature of the freshwater cooling subsystem corresponding to the designated secondary cooler. Based on the third freshwater temperature, it controls the number of seawater pumps activated and their operating speed, and controls the control valve of the designated secondary cooler to its maximum opening. By employing the above technical means, through precise frequency conversion control of the seawater pumps and coolers in the ship's cooling system, it achieves accurate distribution of seawater flow across multiple freshwater cooling systems, thereby avoiding energy waste, improving the control accuracy of the ship's cooling system, and enhancing the stability and reliability of equipment cooling operations. Attached Figure Description

[0016] Figure 1This is a flowchart of a variable frequency control method for a ship cooling system provided in Embodiment 1 of this application; Figure 2 This is a schematic diagram of the ship cooling system in Embodiment 1 of this application; Figure 3 This is a flowchart of the seawater pump control based on the first freshwater temperature in Embodiment 1 of this application; Figure 4 This is a flowchart of the seawater pump control based on the third freshwater temperature in Embodiment 1 of this application; Figure 5 This is a schematic diagram of the structure of a variable frequency control device for a ship cooling system provided in Embodiment 2 of this application; Figure 6 This is a schematic diagram of the structure of an electronic device provided in Embodiment 3 of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application will be described in further detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely for explaining this application and not for limiting it. It should also be noted that, for ease of description, only the parts relevant to this application are shown in the drawings, not all of them. Before discussing exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but may also have additional steps not included in the drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0018] Example 1: Figure 1 A flowchart of a variable frequency control method for a ship cooling system according to Embodiment 1 of this application is provided. The variable frequency control method for the ship cooling system provided in this embodiment can be executed by a variable frequency control device for the ship cooling system. This variable frequency control device can be implemented through software and / or hardware. The variable frequency control device can consist of two or more physical entities, or it can consist of a single physical entity. Generally, the variable frequency control device for the ship cooling system can be a system controller, variable frequency controller, or other control equipment for the ship cooling system.

[0019] The following description uses the variable frequency controller of the ship's cooling system as the main body for implementing the variable frequency control method of the ship's cooling system. (Refer to...) Figure 1 The frequency conversion control method of the ship's cooling system specifically includes: S110. When the ship is in navigation mode, the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the slave cooler are collected based on the frequency converter controller. The number of seawater pumps to be turned on and the operating speed are controlled based on the first freshwater temperature, and the opening degree of the control valve of the corresponding slave cooler is controlled based on the second freshwater temperature.

[0020] The variable frequency control method for a ship cooling system disclosed in this application aims to perform variable frequency control of the ship's cooling system under different operating modes, thereby achieving precise distribution of seawater flow to each freshwater cooling system. (Referring to...) Figure 2 The ship cooling system of this application includes a frequency converter 11, a seawater subsystem 12, multiple freshwater cooling subsystems 13, and multiple corresponding central coolers (141, 142, and 143). The seawater subsystem 12 is connected to each central cooler (141, 142, and 143) through seawater circulation pipes. Each freshwater cooling subsystem 13 is connected to the corresponding central cooler (141, 142, and 143) through freshwater circulation pipes. The central coolers (141, 142, and 143) are used for heat exchange between seawater in the seawater circulation pipes and freshwater in the freshwater circulation pipes to perform equipment cooling operations. The central coolers (141, 142, and 143) include a main cooler 141 and several secondary coolers (142 and 143). The seawater circulation pipeline is equipped with a seawater pump 15 and a control valve 16 corresponding to each secondary cooler. The seawater pump 15 is used to control the total inlet flow of the seawater subsystem 12, and the control valve 16 is used to control the inlet flow of the corresponding secondary cooler. Each freshwater cooling subsystem 13 is equipped with a temperature sensor 17 in its corresponding freshwater circulation pipeline to detect the freshwater temperature of the corresponding freshwater circulation pipeline in real time. The frequency converter 11 is connected to the seawater pump 15, the control valve 16, and the temperature sensor 17 respectively.

[0021] When the seawater subsystem 12 is running, seawater is introduced from the seawater tank 18 into the seawater circulation pipeline, and then the seawater pump 15 and control valve 16 are controlled based on the frequency conversion control method of this application, thereby realizing the seawater flow distribution of each central cooler.

[0022] During ship navigation, the frequency converter first acquires the initial freshwater temperature of the freshwater cooling subsystem connected to the main cooler. Based on this core temperature value, the controller dynamically adjusts the number of seawater pumps activated (in parallel operation) and their operating speed (frequency converter operation). It should be noted that the main cooler generally provides cooling for the ship's core heat load, and cooling during ship operation is primarily provided by the main cooler; therefore, the main cooler directly controls the seawater flow rate through the seawater pumps.

[0023] Understandably, if the initial freshwater temperature is higher than the set value, it indicates a high demand for heat dissipation from the core equipment. In this case, the number of operating seawater pumps or their speeds are increased to increase the total seawater flow rate. Conversely, the number of pumps or their speeds are reduced to decrease the total flow rate. This ensures a precisely matched total cooling capacity for the ship's core thermal load, avoiding the risks of overcooling and energy waste caused by excessive total seawater flow rate under low loads with traditional fixed-frequency pumps, or insufficient cooling during sudden load increases. This significantly improves the operational safety of the core equipment and the system's energy efficiency.

[0024] Meanwhile, in navigation mode, the frequency converter controller collects the second freshwater temperature of each freshwater cooling subsystem connected to a slave cooler (such as a generator, auxiliary machine, or other heat loads). For each slave cooler, the controller independently adjusts the opening of the control valve on its seawater inlet pipe according to its corresponding second freshwater temperature.

[0025] Understandably, if the freshwater temperature corresponding to a certain cooler is too high, its control valve is opened wider to increase the seawater flow through that cooler and enhance its heat exchange capacity; conversely, the valve is closed to reduce the seawater flow. This achieves precise, on-demand allocation of seawater flow to different freshwater cooling subsystems (i.e., different equipment), solving the problem of uneven cooling load distribution when multiple systems operate in parallel. Each piece of equipment receives a cooling seawater flow precisely matched to its actual heat dissipation, preventing some equipment from being overcooled at low loads and ensuring sufficient cooling for all equipment under high loads or sudden load changes, further optimizing system efficiency and equipment protection.

[0026] Optionally, refer to Figure 3 The number of seawater pumps activated and their operating speed are controlled based on the temperature of the first freshwater source, including: S1101. When multiple seawater pumps are turned on, if a designated seawater pump is running at its lowest speed and the first freshwater temperature is lower than a first set threshold, the designated seawater pump shall be turned off. S1102. If the temperature of the first freshwater is higher than the second set threshold when one seawater pump is turned on, the number of seawater pumps turned on shall be increased.

[0027] In navigation mode, the frequency converter can finely adjust the number of activated seawater pumps and their operating speed based on the first freshwater temperature corresponding to the main cooler. Specifically, when multiple seawater pumps are running in parallel, if a designated pump (such as the last one activated or the least efficient pump) is already at its set minimum safe operating speed, and the first freshwater temperature corresponding to the main cooler is still below a preset first threshold (indicating excessive total cooling capacity), the controller will decisively shut down that designated seawater pump. Conversely, when only one seawater pump is running, if the first freshwater temperature rises and exceeds a preset second threshold (usually higher than the first threshold, indicating that even a single pump running at full speed cannot meet the cooling requirements of the core equipment), the controller will initiate an operation to increase the number of activated seawater pumps (e.g., activating another standby pump).

[0028] By finely adjusting the number of operating seawater pumps and their operating speeds, the system achieves coordinated optimization of the number of operating seawater pump units and the speed of each pump. Based on the real-time demands of the core heat load, the system minimizes the total power consumption of the seawater pumps while ensuring sufficient cooling capacity. For example, at low loads, redundant pumps are shut down to directly eliminate their energy consumption; when the load increases, the speed of a single pump is prioritized for higher efficiency, and additional pumps are only activated when the maximum speed limit is insufficient. This completely avoids the enormous energy waste associated with traditional fixed-frequency pump units where all pumps operate inefficiently under partial load, or where a single pump operates at full speed under partial load. It maximizes the combined energy-saving potential of frequency conversion and unit control of the pump unit, significantly reducing the energy consumption of the ship's core cooling system.

[0029] Optionally, when optimizing the pump group in navigation mode, if a seawater pump needs to be shut down, the frequency converter will prioritize shutting down the pump with the longest cumulative running time among the currently running pumps. The controller continuously records the running time of each parallel seawater pump. When the pump shutdown condition is triggered, it compares the historical total running time data of all running seawater pumps, marks the pump with the longest running time as the "seawater pump to be shut down," and issues a shutdown command. This achieves a more even distribution of the lifespan of the seawater pump group. By prioritizing the shutdown of the pump with the longest cumulative running time, the system encourages all parallel seawater pumps to have a more average cumulative running time, preventing premature wear or failure of a single or a few pumps due to long-term continuous operation.

[0030] Optionally, increasing the number of seawater pumps that are turned on includes: Based on the cumulative running time of each of the currently inactive seawater pumps, select the seawater pump with the shortest cumulative running time to start.

[0031] Similarly, when the number of seawater pumps needs to be increased in navigation mode, the frequency converter will prioritize starting the pump with the shortest cumulative running time among the currently idle pumps. The controller records the total historical running time of all standby seawater pumps in real time, automatically comparing the data when the pump increase condition is triggered, and starting the pump with the shortest running time among the idle pumps. This achieves balanced wear and tear throughout the entire lifecycle of the seawater pump set. By prioritizing the activation of the pump with the shortest running time, the system forces all parallel pumps to take turns operating, ensuring that the mechanical wear and electrical aging rates of each pump are consistent. While ensuring a seamless improvement in cooling capacity, this maximizes the overall reliability of the pump set, reduces the rate of sudden failures, extends the service life of the equipment, and reduces maintenance costs.

[0032] Optionally, the opening degree of the control valve of the cooler corresponding to the second freshwater temperature is controlled, including: The opening of the control valve of the cooler is dynamically adjusted based on the PID algorithm to keep the temperature of the second fresh water within the set temperature range.

[0033] In navigation mode, the variable frequency controller dynamically adjusts the opening of the seawater control valve in real time based on the second freshwater temperature corresponding to each cooler using a PID (Proportional-Integral-Derivative) control algorithm. The controller continuously feeds back the second freshwater temperature value from a temperature sensor, comparing it with a preset temperature range (e.g., 75±2℃). The PID algorithm calculates the optimal control valve opening command based on the current temperature deviation (proportional term), historical cumulative deviation (integral term), and temperature change trend (derivative term), and adjusts the valve opening in real time. If the temperature is too high, the opening is increased to enhance seawater flow and improve heat dissipation; if the temperature is too low, the opening is decreased to limit flow and prevent overcooling. This strategy achieves precise, stable, and adaptive control of multi-device cooling, allowing for preemptive increase of valve openings during sudden load changes (such as sudden loading of auxiliary equipment), effectively suppressing temperature fluctuations and preventing short-term overheating. Even under low loads, it maintains stable water temperature within the set range, completely eliminating the periodic temperature oscillations caused by traditional on / off control. Each slave cooler valve is independently adjusted as needed, avoiding frequent valve starts and stops or large movements, reducing mechanical wear and minimizing interference with the overall seawater flow, thus ensuring the stability of the main cooler control. Ultimately, PID control enables different equipment to achieve "constant temperature" cooling quality under various operating conditions, significantly improving equipment lifespan and operational safety, while further unlocking energy-saving potential by preventing overcooling.

[0034] For example, based on the above control strategy, assuming two seawater pumps are running in navigation mode, temperature data is collected by temperature sensors corresponding to the main and secondary coolers. These temperature sensors control the frequency conversion of the seawater pumps. The temperature sensor of the secondary cooler controls the opening of the corresponding control valve, thereby controlling the flow rate of seawater into the secondary cooler. If, when the seawater pump is running at its lowest speed, the freshwater temperature in the main cooler is still below the temperature threshold, one seawater pump is shut down, and the other pump supplies water, achieving greater energy savings. When one seawater pump is running, if the temperature of the temperature sensor corresponding to the main cooler exceeds the threshold, the other seawater pump is started, thus realizing frequency conversion control of the ship's cooling system.

[0035] S120. When the ship is in berthing mode, shut down the main cooler, collect the third freshwater temperature of the freshwater cooling subsystem corresponding to the designated slave cooler based on the frequency converter, control the number of seawater pumps to be turned on and the operating speed based on the third freshwater temperature, and control the control valve corresponding to the designated slave cooler to the maximum opening degree.

[0036] Furthermore, when the vessel is in berthing mode, the main engine is typically not running, and therefore the main cooler is shut down. At this time, the variable frequency drive (VFD) designates a still-operating slave cooler (e.g., a cooler serving the generator or important auxiliary machinery) as a reference and collects the third freshwater temperature of its corresponding freshwater cooling subsystem. Based on this third freshwater temperature, the controller dynamically adjusts the number of seawater pumps activated and their operating speed. The process is similar to that in navigation mode, but the control target is the freshwater temperature of this designated slave cooler. By automatically adapting to berthing conditions, the focus is on critical equipment that still requires cooling. By controlling the total flow rate of the seawater pumps via VFD, the significant energy waste of operating the pumps at rated flow rate under low heat loads during berthing is avoided, significantly reducing auxiliary energy consumption during berthing.

[0037] Furthermore, in berthing mode, for the designated reference cooler, the controller sets its corresponding seawater control valve to maximum opening. The frequency converter can directly output a control signal to fully open the valve. This ensures that the cooler serving this critical equipment receives maximum seawater flow, eliminating resistance that might result from valve throttling. Seawater flow regulation is achieved entirely through the speed of the frequency converter pump, maximizing the reliability and efficiency of the equipment's cooling. Simultaneously, the valves of other non-operating coolers remain closed or at minimum opening, avoiding unnecessary seawater circulation losses.

[0038] Optionally, refer to Figure 4 The number of seawater pumps activated and their operating speed are controlled based on the temperature of the third freshwater source, including: S1201. When multiple seawater pumps are turned on, if a designated seawater pump is running at its lowest speed and the temperature of the third freshwater is lower than the first set threshold, the designated seawater pump shall be turned off. S1202. If the temperature of the third freshwater is higher than the second set threshold when one seawater pump is turned on, the number of seawater pumps turned on shall be increased.

[0039] In ship berthing mode, the frequency converter controls the seawater pump operation using a stepped strategy based on the specified third freshwater temperature from the cooler. Specifically, when multiple pumps are running and a pump is at its lowest speed, if the third freshwater temperature is below the first set threshold for overcooling (e.g., 30°C), the seawater pump with the longest cumulative running time is prioritized for shutdown. When only a single pump is running, if the temperature exceeds the second set threshold for overheating (e.g., 34°C), the standby pump with the shortest cumulative idle time is activated. This design, through dual temperature threshold hysteresis control and a pump rotation mechanism, achieves extreme energy savings while ensuring the cooling safety of equipment (such as generators), and avoids equipment damage caused by frequent pump start-stop cycles.

[0040] For example, based on the above control strategy, assuming two seawater pumps are running, in berthing mode, the control valve automatically opens to its maximum degree and the main cooler is shut down. If, when one of the seawater pumps is at its lowest frequency, the freshwater temperature corresponding to the currently running cooler is below a threshold, one seawater pump is shut down, and the other pump supplies water, thus achieving a more energy-efficient effect. When one seawater pump is running, if the temperature sensor reading exceeds the threshold, the other seawater pump is started, thereby realizing frequency conversion control of the ship's cooling system.

[0041] Optionally, in the set operating mode, this application controls the seawater pump to operate at full load and sets the control valve to the maximum opening degree.

[0042] When the operator switches to the set operating mode (such as manual operation mode), the frequency converter will completely bypass the above-mentioned automatic control logic and directly force all seawater pumps to operate at their rated full-load speed (i.e., 100% frequency output), while locking all seawater control valves from the cooler to their maximum opening. This design essentially switches the system to a backup state with maximum cooling capacity, providing absolutely reliable cooling protection for the ship to cope with extreme operating conditions (such as main engine overload, severe cooler fouling, or automatic control system failure), ensuring that the equipment temperature does not exceed the safety limit under any circumstances.

[0043] Optionally, this application also detects ship operating condition signals and switches between navigation and berthing modes based on these signals.

[0044] By collecting key ship operating condition signals in real time (such as main engine speed, propeller status, GPS speed, and anchor winch sensor signals), the system automatically determines and switches the operating mode of the cooling system. When the main engine is detected to be running continuously and the ship's speed is higher than a set threshold (e.g., 5 knots), the system immediately switches to sailing mode and activates the main cooler control logic. When the main engine is detected to be shut down or the ship is stationary for more than a set time (e.g., 30 minutes), the system switches to mooring mode, shuts down the main cooler, and activates the auxiliary engine cooling logic. This avoids the delays or operational risks that may result from manual mode switching (e.g., energy waste caused by forgetting to switch modes after mooring), and more accurately responds to transient changes in the ship's operating conditions (e.g., frequent starts and stops when entering and leaving port), ensuring that the cooling strategy is always matched with the equipment's heat load in real time. Especially in the event of a sudden failure (e.g., a sudden main engine shutdown during navigation), the system can automatically switch to mooring mode in a short time to prevent the seawater pumps from running at full load without load, elevating the synergy between safety redundancy and energy efficiency optimization to a new level.

[0045] For the architecture design of multiple freshwater cooling systems corresponding to one seawater system, this application can effectively solve the problem of precise frequency conversion control of seawater pumps based on temperature, and effectively allocate seawater flow to different coolers, making full use of seawater volume, thereby achieving a more energy-saving effect.

[0046] Optionally, the ship's cooling system can also construct a real-time digital twin, integrating multi-source sensor data such as pump vibration spectrum, seawater corrosive conductivity, and cooler infrared thermal imaging, and training a time-series prediction model through edge computing nodes. This twin dynamically simulates the physical system state, and when it identifies that the seawater pump efficiency decline exceeds a threshold (such as impeller cavitation causing a 7% increase in power consumption), it automatically triggers a pre-maintenance work order and simultaneously optimizes PID parameters. For example, it can adaptively reduce the integral coefficient in high-algae waters to suppress valve oscillation, or predict the remaining life of seals based on the frequency of control valve actions and seawater sediment content, and dynamically adjust the response level of spare parts.

[0047] Furthermore, an Organic Rankine Cycle (ORC) power generation module is embedded in the high-temperature freshwater circuit (>85°C) of the central cooler, with intelligent power distribution via a frequency converter. During high-load conditions, high-temperature freshwater is preferentially directed to the ORC evaporator for power generation (peak output 120kW), and the cooled freshwater (approximately 65°C) is returned to the central cooler. During low-load conditions, the ORC circuit is shut off to ensure basic cooling. Based on the ship's grid load and lithium battery SOC, the controller automatically activates the ORC for compensating power supply during seawater pump deceleration. Its condenser is connected in parallel to the seawater subsystem, thereby reducing the total flow demand. Through the frequency converter coordination between the ORC power generation cold end and the seawater pump, the triple energy efficiency chain of waste heat recovery, power replenishment, and pump consumption reduction is optimized.

[0048] The above describes a system where, when the ship is in sailing mode, a frequency converter collects the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the secondary cooler. The first freshwater temperature is used to control the number of seawater pumps activated and their operating speed, while the second freshwater temperature controls the opening of the control valves of the corresponding secondary coolers. When the ship is in moored mode, the main cooler is shut off, and the frequency converter collects the third freshwater temperature of the designated secondary cooler's freshwater cooling subsystem. The third freshwater temperature is used to control the number of seawater pumps activated and their operating speed, and the control valves of the designated secondary coolers are kept at their maximum opening. By employing this technology, precise frequency conversion control of the ship's cooling system's seawater pumps and coolers enables accurate distribution of seawater flow across multiple freshwater cooling systems, thereby avoiding energy waste, improving the control accuracy of the ship's cooling system, and enhancing the stability and reliability of equipment cooling operations.

[0049] Example 2: Based on the above embodiments, Figure 4 This is a schematic diagram of the structure of a variable frequency control device for a ship cooling system provided in Embodiment 2 of this application. The ship cooling system of this application includes a variable frequency controller, a seawater subsystem, multiple freshwater cooling subsystems, and multiple corresponding central coolers. The seawater subsystem is connected to each central cooler through seawater circulation pipes, and each freshwater cooling subsystem is connected to its corresponding central cooler through freshwater circulation pipes. The central cooler is used for heat exchange between seawater in the seawater circulation pipes and freshwater in the freshwater circulation pipes to perform equipment cooling operations. The central cooler includes a main cooler and several slave coolers. The seawater circulation pipes are equipped with seawater pumps and control valves corresponding to each slave cooler. The seawater pumps are used to control the total inlet flow of the seawater subsystem, and the control valves are used to control the inlet flow of the corresponding slave coolers. Each freshwater cooling subsystem's corresponding freshwater circulation pipe is equipped with a temperature sensor for real-time detection of the freshwater temperature in the corresponding freshwater circulation pipe. The variable frequency controller is connected to the seawater pumps, control valves, and temperature sensors respectively. refer to Figure 4 The variable frequency control device for the ship cooling system provided in this embodiment specifically includes: a navigation control module 21 and a mooring control module 22.

[0050] Among them, the navigation control module 21 is used to collect the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the slave cooler based on the frequency converter when the ship is in navigation mode, control the number of seawater pumps to be turned on and the operating speed based on the first freshwater temperature, and control the opening degree of the control valve of the corresponding slave cooler based on the second freshwater temperature. The mooring control module 22 is used to shut down the main cooler when the ship is in mooring mode, collect the third freshwater temperature of the freshwater cooling subsystem corresponding to the designated slave cooler based on the frequency converter, control the number of seawater pumps to be turned on and the operating speed based on the third freshwater temperature, and control the control valve corresponding to the designated slave cooler to the maximum opening degree.

[0051] Specifically, the number of seawater pumps activated and their operating speed are controlled based on the temperature of the first freshwater source, including: If multiple seawater pumps are turned on, and a designated seawater pump is running at its lowest speed and the first freshwater temperature is lower than a first set threshold, the designated seawater pump will be turned off. If the temperature of the first freshwater is higher than the second set threshold when one seawater pump is turned on, the number of seawater pumps turned on will be increased.

[0052] Increase the number of seawater pumps in operation, including: Select the seawater pump with the shortest cumulative running time from all currently inactive seawater pumps and start it.

[0053] The opening degree of the control valve of the cooler corresponding to the second freshwater temperature control includes: The opening of the control valve of the cooler is dynamically adjusted based on the PID algorithm to keep the temperature of the second fresh water within the set temperature range.

[0054] Specifically, the number of seawater pumps activated and their operating speed are controlled based on the temperature of the third freshwater source, including: If multiple seawater pumps are turned on, and a designated seawater pump is running at its lowest speed and the temperature of the third freshwater is lower than the first set threshold, the designated seawater pump will be turned off. If the temperature of the third freshwater exceeds the second set threshold when one seawater pump is turned on, the number of seawater pumps turned on will be increased.

[0055] In addition, the variable frequency control device for the ship's cooling system also includes: In the set operating mode, the seawater pump is controlled to run at full load, and the control valve is set to maximum opening.

[0056] Detect ship operating condition signals and switch between navigation and berthing modes based on these signals.

[0057] The above describes a system where, when the ship is in sailing mode, a frequency converter collects the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the secondary cooler. The first freshwater temperature is used to control the number of seawater pumps activated and their operating speed, while the second freshwater temperature controls the opening of the control valves of the corresponding secondary coolers. When the ship is in moored mode, the main cooler is shut off, and the frequency converter collects the third freshwater temperature of the designated secondary cooler's freshwater cooling subsystem. The third freshwater temperature is used to control the number of seawater pumps activated and their operating speed, and the control valves of the designated secondary coolers are kept at their maximum opening. By employing this technology, precise frequency conversion control of the ship's cooling system's seawater pumps and coolers enables accurate distribution of seawater flow across multiple freshwater cooling systems, thereby avoiding energy waste, improving the control accuracy of the ship's cooling system, and enhancing the stability and reliability of equipment cooling operations.

[0058] The frequency conversion control device for the ship cooling system provided in Embodiment 2 of this application can be used to execute the frequency conversion control method for the ship cooling system provided in Embodiment 1 above, and has corresponding functions and beneficial effects.

[0059] Example 3: This application provides an electronic device in embodiment three, referring to... Figure 5 The electronic device includes a processor 31, a memory 32, a communication module 33, an input device 34, and an output device 35. The electronic device may have one or more processors and one or more memories. The processor, memory, communication module, input device, and output device of the electronic device can be connected via a bus or other means.

[0060] Memory, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the frequency conversion control method of the ship cooling system described in any embodiment of this application (e.g., the navigation control module and berthing control module in the frequency conversion control device of the ship cooling system). Memory may primarily include a program storage area and a data storage area, wherein the program storage area may store the operating system and at least one application program required for a function; the data storage area may store data created based on the use of the device, etc. Furthermore, memory may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some instances, memory may further include memory remotely located relative to the processor, and these remote memories can be connected to the device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0061] The communication module is used for data transmission.

[0062] The processor executes various functional applications and data processing of the device by running software programs, instructions, and modules stored in memory, thereby realizing the frequency conversion control method of the ship cooling system described above.

[0063] Input devices can be used to receive input numerical or character information, and to generate key signal inputs related to user settings and function control of the device. Output devices may include display devices such as displays.

[0064] The electronic equipment provided above can be used to execute the frequency conversion control method of the ship cooling system provided in Embodiment 1 above, and has the corresponding functions and beneficial effects.

[0065] Example 4: This application embodiment also provides a storage medium containing computer-executable instructions. When executed by a computer processor, the computer-executable instructions are used to execute a variable frequency control method for a ship cooling system. The variable frequency control method for the ship cooling system includes: when the ship is in sailing mode, acquiring a first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and a second freshwater temperature of the freshwater cooling subsystem corresponding to the slave cooler based on the variable frequency controller; controlling the number of seawater pumps turned on and their operating speed based on the first freshwater temperature; and controlling the opening degree of the control valve of the corresponding slave cooler based on the second freshwater temperature; when the ship is in moored mode, shutting down the main cooler; acquiring a third freshwater temperature of the freshwater cooling subsystem corresponding to a specified slave cooler based on the variable frequency controller; controlling the number of seawater pumps turned on and their operating speed based on the third freshwater temperature; and controlling the control valve of the specified slave cooler to its maximum opening degree.

[0066] Storage medium – any type of memory device or storage device. The term “storage medium” is intended to include: mounting media, such as CD-ROM, floppy disk, or magnetic tape devices; computer system memory or random access memory, such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory, such as flash memory, magnetic media (e.g., hard disk or optical storage); registers or other similar types of memory elements, etc. Storage medium may also include other types of memory or combinations thereof. Furthermore, storage medium may reside in a first computer system in which the program is executed, or it may reside in a different second computer system connected to the first computer system via a network (such as the Internet). The second computer system can provide program instructions to the first computer for execution. The term “storage medium” can include two or more storage media residing in different locations (e.g., in different computer systems connected via a network). Storage medium may store program instructions (e.g., specifically implemented as a computer program) executable by one or more processors.

[0067] Of course, the computer-executable instructions provided in the embodiments of this application are not limited to the frequency conversion control method of the ship cooling system as described above, but can also perform related operations in the frequency conversion control method of the ship cooling system provided in any embodiment of this application.

[0068] The frequency conversion control device, storage medium, and electronic equipment of the ship cooling system provided in the above embodiments can execute the frequency conversion control method of the ship cooling system provided in any embodiment of this application. For technical details not described in detail in the above embodiments, please refer to the frequency conversion control method of the ship cooling system provided in any embodiment of this application.

[0069] The above description is merely a preferred embodiment and the technical principles employed in this application. This application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions that can be made by those skilled in the art will not depart from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of this application, the scope of which is determined by the scope of the claims.

Claims

1. A variable frequency control method for a ship cooling system, the ship cooling system comprising a variable frequency controller, a seawater subsystem, multiple freshwater cooling subsystems, and multiple corresponding central coolers, wherein the seawater subsystem is connected to each of the central coolers via seawater circulation pipes, and each of the freshwater cooling subsystems is connected to a corresponding central cooler via freshwater circulation pipes, the central coolers being used for heat exchange between seawater in the seawater circulation pipes and freshwater in the freshwater circulation pipes to perform equipment cooling operations; characterized in that, The central cooler includes a main cooler and several secondary coolers. The seawater circulation pipeline is equipped with a seawater pump and control valves corresponding to each of the secondary coolers. The seawater pump is used to control the total inlet flow of the seawater subsystem, and the control valves are used to control the inlet flow of the corresponding secondary cooler. Each freshwater cooling subsystem is equipped with a temperature sensor in its corresponding freshwater circulation pipeline to detect the freshwater temperature in the corresponding freshwater circulation pipeline in real time. The frequency converter is connected to the seawater pump, the control valves, and the temperature sensors respectively. The variable frequency control method for the ship's cooling system includes: when the ship is in sailing mode, the variable frequency controller collects the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the slave cooler; based on the first freshwater temperature, the number of seawater pumps turned on and their operating speed are controlled; and based on the second freshwater temperature, the opening degree of the control valve of the corresponding slave cooler is controlled; when the ship is in moored mode, the main cooler is turned off; based on the variable frequency controller, the variable frequency controller collects the third freshwater temperature of the freshwater cooling subsystem corresponding to the designated slave cooler; based on the third freshwater temperature, the number of seawater pumps turned on and their operating speed are controlled; and the control valve of the designated slave cooler is controlled to its maximum opening degree. The method of controlling the number of seawater pumps turned on and their operating speed based on the first freshwater temperature includes: when multiple seawater pumps are turned on, if a designated seawater pump is operating at its lowest speed and the first freshwater temperature is lower than a first preset threshold, turning off the designated seawater pump; when only one seawater pump is turned on, if the first freshwater temperature is higher than a second preset threshold, increasing the number of seawater pumps turned on. The method of controlling the number of seawater pumps turned on and their operating speed based on the third freshwater temperature includes: when multiple seawater pumps are turned on, if a designated seawater pump is operating at its lowest speed and the third freshwater temperature is lower than the first preset threshold, turning off the designated seawater pump; when only one seawater pump is turned on, if the third freshwater temperature is higher than the second preset threshold, increasing the number of seawater pumps turned on.

2. The variable frequency control method for a ship cooling system according to claim 1, characterized in that, The method of increasing the number of activated seawater pumps includes: selecting the seawater pump with the shortest cumulative running time based on the cumulative running time of each currently inactive seawater pump.

3. The variable frequency control method for a ship cooling system according to claim 1, characterized in that, The control valve opening of the slave cooler corresponding to the second freshwater temperature control includes: dynamically adjusting the opening of the control valve of the slave cooler based on a PID algorithm so that the second freshwater temperature is within a set temperature range.

4. The variable frequency control method for a ship cooling system according to claim 1, characterized in that, The method further includes: controlling the seawater pump to operate at full load in a set operating mode, and setting the control valve to its maximum opening.

5. The variable frequency control method for a ship cooling system according to claim 1, characterized in that, The method further includes: detecting ship operating condition signals, and switching the navigation mode and the berthing mode based on the ship operating condition signals.

6. A variable frequency control device for a ship cooling system, the ship cooling system comprising a variable frequency controller, a seawater subsystem, multiple freshwater cooling subsystems, and multiple corresponding central coolers, wherein the seawater subsystem is connected to each of the central coolers via seawater circulation pipes, and each of the freshwater cooling subsystems is connected to a corresponding central cooler via freshwater circulation pipes, the central coolers being used for heat exchange between seawater in the seawater circulation pipes and freshwater in the freshwater circulation pipes to perform equipment cooling operations; characterized in that, The central cooler includes a main cooler and several secondary coolers. The seawater circulation pipeline is equipped with a seawater pump and control valves corresponding to each of the secondary coolers. The seawater pump is used to control the total inlet flow of the seawater subsystem, and the control valves are used to control the inlet flow of the corresponding secondary cooler. Each freshwater cooling subsystem is equipped with a temperature sensor in its corresponding freshwater circulation pipeline to detect the freshwater temperature in the corresponding freshwater circulation pipeline in real time. The frequency converter is connected to the seawater pump, the control valves, and the temperature sensors respectively. The variable frequency control device of the ship cooling system includes: a navigation control module, which, when the ship is in navigation mode, collects the first freshwater temperature of the freshwater cooling subsystem corresponding to the main cooler and the second freshwater temperature of the freshwater cooling subsystem corresponding to the slave cooler based on the variable frequency controller, controls the number of seawater pumps to be turned on and the operating speed based on the first freshwater temperature, and controls the opening degree of the control valve of the corresponding slave cooler based on the second freshwater temperature. The berthing control module is used to shut down the main cooler when the ship is in berthing mode, collect the third freshwater temperature of the freshwater cooling subsystem corresponding to the designated slave cooler based on the frequency converter, control the number of seawater pumps to be turned on and their operating speed based on the third freshwater temperature, and control the control valve corresponding to the designated slave cooler to the maximum opening degree.

7. An electronic device, characterized in that, include: Memory and one or more processors; The memory is used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the variable frequency control method for a ship cooling system as described in any one of claims 1 to 5.

8. A storage medium containing computer-executable instructions, characterized in that, The computer-executable instructions, when executed by a computer processor, are used to perform the frequency conversion control method for a ship cooling system as described in any one of claims 1 to 5.

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