A ship multimodal energy management and adaptive load distribution system

Abstract

The application relates to the technical field of ship propulsion, in particular to a ship multi-mode energy management and adaptive load distribution system, which comprises an acquisition module, a correction module configured to limitively correct the received original power by using the pitch angular velocity and the heave acceleration of the ship to obtain target total power, a determination module configured to acquire the health state parameters and the internal resistance parameters of each battery pack in a plurality of parallel battery packs, determine a first distribution value based on the health state parameters, and determine a second distribution value based on the internal resistance parameters, and a distribution module configured to distribute the target total power to each battery pack according to the first distribution value and the second distribution value. Through the above technical scheme, adaptive load distribution can be performed on the ship.

Description

Technical Field

[0001] This application relates to the field of ship propulsion technology, and in particular to a ship multi-mode energy management and adaptive load distribution system. Background Technology

[0002] To meet the power requirements of ships, parallel battery packs have become the mainstream power configuration and are widely used in marine power systems. Parallel battery packs, through the coordinated power supply of multiple battery modules, can effectively improve the total capacity and output power of the power system, ensuring the power supply of ships under heavy load and long-range conditions. The modular design of parallel battery packs also facilitates later maintenance, expansion and replacement, adapting to the personalized power requirements of ships of different tonnages and under different operating conditions.

[0003] However, during actual ship navigation, factors such as complex sea conditions, changes in navigation conditions, and differences in the characteristics of the battery pack itself mean that the traditional fixed-ratio load distribution method can no longer meet the requirements for efficient and stable system operation. Uneven load distribution may lead to accelerated battery degradation or an increased risk of thermal runaway, shortening the overall lifespan of the battery pack. Changes in ship attitude caused by sea state fluctuations can lead to sudden changes in propulsion system load. Fixed distribution strategies cannot respond quickly to load changes, which may result in insufficient power output or redundant energy consumption, reducing the operating efficiency of the power system. Therefore, it is necessary to implement multi-mode energy management and adaptive load distribution for ships. Summary of the Invention

[0004] To perform multi-mode energy management and adaptive load allocation for ships, this application provides a ship multi-mode energy management and adaptive load allocation system, including: an acquisition module configured to acquire the ship's surface speed, propulsion motor speed, pitch rate, and heave acceleration; determine slip parameters based on the surface speed, propulsion motor speed, and propeller pitch; and determine a first attenuation term using the deviation of the slip parameters from a preset slip rate; and a correction module configured to determine a motion attitude index using the pitch rate and heave acceleration; determine a second attenuation term based on the motion attitude index; and compare the first attenuation term with the second attenuation term. The first product of the two attenuation terms is used as a correction coefficient; the received original power is constrained and corrected using the correction coefficient to obtain the target total power; the determination module is configured to acquire the health status parameters and internal resistance parameters of each battery pack in multiple parallel battery packs, determine a first allocation value based on the health status parameters, and determine a second allocation value based on the internal resistance parameters; the allocation module is configured to determine a dynamic switching factor based on the motion attitude index, and use the dynamic switching factor to perform a weighted summation of the first allocation value and the second allocation value to obtain the power allocation weight of the battery pack, so as to allocate the target total power to each battery pack according to the power allocation weight.

[0005] In this way, by introducing slip parameters and motion attitude index, when abnormal propeller slip rate or violent hull movement is detected, the original power is actively limited, effectively preventing motor overspeed and mechanical overload caused by propeller water ejection, and protecting the propulsion shaft system; under stable sea conditions, the load is tended to be distributed based on the health status to achieve balanced aging of the battery pack; under severe sea conditions, the load is smoothly switched to a distribution strategy based on internal resistance, prioritizing the use of batteries with low internal resistance to bear the impact of large currents, thereby reducing system heat generation and energy loss.

[0006] Optionally, the slip parameter is determined by: taking the second product of the propulsion motor speed and the propeller's geometric pitch as the theoretical advance speed, and taking the largest of the theoretical advance speed and a preset positive value as the denominator; determining the first ratio of the water speed to the denominator, and taking the first difference between 1 and the first ratio as the slip parameter.

[0007] Optionally, the motion attitude index is determined as follows: the second ratio of the pitch angular velocity to a preset pitch angular velocity threshold is taken as the pitch component, and the third ratio of the heave acceleration to a preset heave acceleration threshold is taken as the heave component; the square of the pitch component and the sum of the squares of the heave component are determined, and the arithmetic square root of the sum of the squares is taken as the motion attitude index.

[0008] In this way, the pitch angular velocity and heave acceleration can be combined to determine the motion attitude index that reflects the motion state of the ship.

[0009] Optionally, the first attenuation term is obtained by processing the deviation of the slip parameter relative to the preset slip rate using an exponential attenuation function, and the first attenuation term is negatively correlated with the deviation; the second attenuation term is obtained by processing the motion attitude index using an inverse proportional function.

[0010] Optionally, the target total power is determined as follows: calculate the second difference between value 1 and the preset coefficient, and calculate the third product of the second difference and the correction coefficient, so that the sum of the third product and the preset coefficient is used as the comprehensive adjustment factor; multiply the original power by the comprehensive adjustment factor to obtain the intermediate power reference value; calculate the third difference between the intermediate power reference value and the target total power of the previous control cycle; use the preset maximum power change rate to perform upper and lower limit processing on the third difference to obtain the limited power change amount; and use the sum of the limited power change amount and the target total power of the previous control cycle as the target total power at the current moment.

[0011] In this way, in addition to limiting the power amplitude, a rate of change limit is further introduced, which not only prevents the power amplitude from being too large, but also smooths the step change of the power command, avoiding motor torque pulsation and grid voltage flicker caused by sudden changes in control commands.

[0012] Optionally, the acquisition module is also configured to perform the following steps: acquire water depth data through a depth sounder and calculate a fourth ratio of the water depth data to the ship's draft; when the fourth ratio is less than a preset ratio threshold, replace the preset slip rate used to calculate the first attenuation term with a preset shallow water correction value; the shallow water correction value is greater than the preset slip rate setting value when the ship is navigating in deep water.

[0013] In this way, the changes in hydrodynamic characteristics caused by the shallow water effect when the ship is navigating in shallow water are fully considered. By automatically adjusting the slip rate benchmark value, the erroneous power limitation caused by the increased shallow water resistance being misjudged as a propeller failure is avoided, thus ensuring the maneuverability of the ship when entering or leaving the port or operating in shallow water.

[0014] Optionally, the correction module is also configured to perform the following steps: calculate the derivative of the propulsion motor speed with respect to time to obtain the shaft speed acceleration; when the shaft speed acceleration is greater than a preset acceleration threshold, set the target total power to zero or a preset idle power value until the phase current of the propulsion motor is detected to rise back to a preset current threshold.

[0015] Optionally, the first allocation value is positively correlated with the health status parameter, and the second allocation value is negatively correlated with the internal resistance parameter. The power allocation weight of the battery pack is determined in the following way: calculate the fourth difference between the value 1 and the dynamic switching factor, multiply the fourth difference by the first allocation value to obtain the first weighting term, multiply the dynamic switching factor by the second allocation value to obtain the second weighting term, and use the sum of the first weighting term and the second weighting term as the power allocation weight of the battery pack.

[0016] This allows the battery load distribution strategy to smoothly transition between prioritizing lifespan and performance, avoiding the shocks that may be caused by hard switching.

[0017] Optionally, the dynamic switching factor is determined in the following ways: when the motion attitude index is greater than a preset stability threshold, the dynamic switching factor is set to a first preset value that maximizes the proportion of the second weighting term in the power allocation weight; when the motion attitude index is less than or equal to the preset stability threshold, the dynamic switching factor is set to a second preset value that maximizes the proportion of the first weighting term in the power allocation weight.

[0018] Optionally, the target total power is allocated to each battery pack according to the power allocation weight, including: taking the sum of the power allocation weights of all parallel battery packs as the total weight value; calculating the proportion of the power allocation weight of each battery pack to the total weight value to obtain the normalized allocation coefficient of each battery pack; calculating the product of the target total power and the normalized allocation coefficient to obtain the final power value that each battery pack should bear; and sending the final power value to the battery management unit corresponding to each battery pack for execution.

[0019] The technical solutions provided by the embodiments of this application may include the following beneficial effects: obtaining the ship's speed over water, propulsion motor speed, pitch rate, and heave acceleration; determining correction coefficients based on the speed over water, propulsion motor speed, and propeller pitch; using the correction coefficients to perform restrictive corrections on the received raw power to obtain the target total power; and allocating the target total power based on the health status parameters and internal resistance parameters of each battery pack in multiple parallel battery packs, thereby performing adaptive load distribution on the ship, enabling the ship to adapt to different motion states, and balancing the improvement of ship stability with the extension of battery pack lifespan.

[0020] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a ship multi-mode energy management and adaptive load distribution system according to an exemplary embodiment;

[0022] Figure 2 This is a schematic diagram illustrating the changes in the motion posture index in the embodiments of this application;

[0023] Figure 3 This is a schematic diagram illustrating the change in the target total power in the embodiments of this application;

[0024] Figure 4 This is a schematic diagram illustrating the weights assigned to different battery packs in an embodiment of this application. Detailed Implementation

[0025] First, a brief introduction to the application scenarios of the embodiments of this application will be given. The application scenarios of the embodiments of this application can be electric propulsion vessels with sea state operation requirements, such as offshore oil support vessels, oceanographic research vessels, deep-sea cable-laying vessels, or semi-submersible engineering platforms equipped with dynamic positioning systems.

[0026] When performing their missions, these vessels not only need to deal with sea conditions caused by wind and waves, but also need to frequently switch between shallow water ports, offshore wind farms and deep-sea operation areas. Their power systems usually adopt a comprehensive electric propulsion architecture with DC or AC grids, and include multiple sets of parallel lithium-ion battery packs, such as lithium iron phosphate or ternary lithium batteries, as propulsion power, peak-shaving power or backup power. It is necessary to implement adaptive load distribution for the vessels.

[0027] To enable adaptive load allocation for ships, embodiments of this application provide a ship multi-mode energy management and adaptive load allocation system 1000. Figure 1 This is a schematic diagram illustrating the structure of a ship multi-mode energy management and adaptive load distribution system 1000 according to an exemplary embodiment, as shown below. Figure 1As shown, the ship multi-mode energy management and adaptive load allocation system 1000 includes: an acquisition module 1100, a correction module 1200, a determination module 1300, and an allocation module 1400.

[0028] The ship's multi-mode energy management and adaptive load allocation system 1000 can be implemented based on a general-purpose computer hardware architecture, including a processor and memory. The memory stores computer program instructions, which, when executed by the processor, implement the functions of the following modules. The processor can be an embedded controller in a ship automation system or power management system, such as a programmable logic controller.

[0029] The acquisition module 1100 is configured to acquire the ship's speed in the water, propulsion motor speed, pitch rate and heave acceleration, and determine slip parameters based on the speed in the water, propulsion motor speed and propeller pitch, so as to determine the first attenuation term by using the deviation of the slip parameters from the preset slip rate.

[0030] In one embodiment, the process of obtaining the slip parameter by the module 1100 is as follows: the second product of the propulsion motor speed and the geometric pitch of the propeller is used as the theoretical advance speed, and the larger of the theoretical advance speed and the preset positive value is used as the denominator; the first ratio of the water speed to the denominator is determined, and the first difference between 1 and the first ratio is used as the slip parameter.

[0031] The acquisition module 1100 can collect data in real time through the ship's sensor network, and the water speed can be obtained through a Doppler log or electromagnetic log installed on the bottom of the ship.

[0032] The propulsion motor speed can be obtained through an encoder or rotary transformer inside the motor driver, while the pitch rate and heave acceleration can be obtained through the ship's motion reference unit or inertial navigation system. These sensors can be installed at the ship's center of gravity or near the propeller to accurately reflect the motion state at the propeller.

[0033] slip parameters in the embodiments of this application ,in, Indicates the ship's speed over water; G represents the speed of the propulsion motor, and G represents the geometric pitch of the propeller, which is the theoretical distance the propeller travels in one revolution. It is usually a fixed value or a value that changes in real time according to the pitch angle. It is a preset positive value, such as 0.001, used to prevent calculation errors caused by a zero denominator when the ship is stationary and the motor is stopped.

[0034] When a ship is sailing in wind and waves, the propeller may partially emerge from the water or draw in air. The thrust generated by the propeller is proportional to the square of the rotational speed. When the propeller emerges from the water, the density of the medium around the propeller drops from the density of water to the density of a mixture of air and water, causing a sharp drop in load torque.

[0035] Under the same input power, the motor speed will rise abnormally, while the ship speed may remain unchanged or decrease due to the increase in wave resistance, making the theoretical advance speed greater than the actual advance speed, and the slip parameter increases and approaches 1.

[0036] Conversely, under normal navigation conditions, the propeller is completely submerged, and the slip parameter is usually maintained within a preset range. By monitoring the slip parameter in real time, the propeller's water-grabbing efficiency can be directly quantified. If the slip parameter rises abnormally, it indicates that the propeller's propulsion efficiency has decreased. If high power output is maintained, the excess energy will be converted into water turbulence energy or cause the motor to overspeed. Therefore, calculating the slip parameter helps to avoid ineffective work and mechanical damage.

[0037] In one embodiment, the acquisition module 1100 is further configured to perform the following steps: acquire water depth data through a depth sounder and calculate a fourth ratio of the water depth data to the ship's draft; when the fourth ratio is less than a preset ratio threshold, replace the preset slip rate used to calculate the first attenuation term with a preset shallow water correction value; the shallow water correction value is greater than the preset slip rate setting value when the ship is navigating in deep water.

[0038] When a ship enters or leaves a port or operates in shallow water, the gap between the ship's bottom and the seabed decreases, the flow field under the ship's bottom is compressed and the flow velocity increases, resulting in a decrease in the pressure under the ship's bottom and causing the ship to sink, which is known as the shallow water effect. The shallow water effect increases the ship's frictional resistance and wave-making resistance. At the same propeller speed, the ship speed will decrease due to the increase in resistance, which in turn increases the calculated slip parameters.

[0039] If the preset slip rate in deep water is still used as the benchmark, it will be misjudged as an abnormal propeller condition and power limitation will be triggered incorrectly. This will cause the ship to lose power when it needs high power to overcome shallow water resistance, which may result in loss of maneuverability or even grounding.

[0040] For example, if the depth sounder measures a water depth of 15 meters and the ship's draft is 10 meters, the ratio is 1.5. If the preset ratio threshold is 2, it can be determined that the ship has entered a shallow water area. The preset slip ratio can be increased to a shallow water correction value, such as 0.35, which can distinguish between increased physical resistance and propeller malfunction, thereby maximizing power output while ensuring safety.

[0041] The correction module 1200 is configured to determine the motion attitude index using the pitch angular velocity and heave acceleration, and determine the second attenuation term based on the motion attitude index, and use the first product of the first attenuation term and the second attenuation term as the correction coefficient; and use the correction coefficient to perform restrictive correction on the received raw power to obtain the target total power.

[0042] In one embodiment, the correction module 1200 determines the motion attitude index in the following manner: taking the second ratio of the pitch angular velocity to a preset pitch angular velocity threshold as the pitch component, and taking the third ratio of the heave acceleration to a preset heave acceleration threshold as the heave component; determining the square of the pitch component and the sum of the squares of the heave component, and taking the arithmetic square root of the sum of squares as the motion attitude index.

[0043] Pitching and heave are the two degrees of freedom that have the greatest impact on the working depth of the propeller. When a ship pitches violently, the bow and stern will rise and fall alternately; when heave occurs, the entire ship rises and falls as a whole. The superposition of these two motions will change the propeller's depth.

[0044] This application embodiment constructs a motion posture index. ,in, This represents the measured pitch angular velocity; This indicates the preset pitch rate threshold, which can be set in advance according to the ship's stability manual. It represents the critical value at which the ship begins to exhibit significant pitch. This represents the measured heave acceleration; This indicates the preset heave acceleration threshold.

[0045] The motion attitude index is constructed by taking the square root of the normalized sum of squares, which can take into account the coupling effect of pitch and heave with equal weight. Furthermore, the normalization process eliminates the influence of angular velocity and acceleration, two different physical dimensions, making the motion attitude index a dimensionless and standardized indicator of sea state severity. When the motion attitude index is greater than 1, it indicates that the ship's motion state has reached the warning line that may lead to propeller spillage or severe load fluctuations.

[0046] By using motion attitude indices, we can not only sense the current motion state, but also predict upcoming load changes, which helps to achieve feedforward power intervention.

[0047] In one embodiment, when the correction module 1200 calculates the attenuation term, the first attenuation term is obtained by processing the deviation of the slip parameter relative to the preset slip rate using an exponential attenuation function, and the first attenuation term is negatively correlated with the deviation; the second attenuation term is obtained by processing the motion attitude index using an inverse proportional function.

[0048] First attenuation term ,in, It is a preset slip rate. This is the first adjustment gain coefficient, which can be set to, for example, 10, representing the actual slip parameter. Not exceeding the benchmark value The maximum value function `max` takes the value of 0, and the first decay term remains at 1; the actual slip parameters Exceeding the benchmark value At that time, the correction factor will decrease exponentially.

[0049] Excessively high slip parameters often mean that the propeller is about to enter a free-running state. The exponential function has the characteristic that the derivative increases as the independent variable increases, that is, the larger the deviation, the faster the decay rate, which meets the protection requirement of rapid response once the limit is exceeded.

[0050] Second attenuation term ,in, This is the threshold for the activity index, for example, 0.8. This is the second adjustment gain coefficient, which can be set to 5 for example, and max is the maximum value.

[0051] Ship motion has a large inertia, and the decay curve provided by the inverse proportional function is relatively gentle. It can suppress the power impact caused by violent motion and avoid the ship losing power due to sudden changes in control quantity. Compared with the sharp truncation of the exponential function, the inverse proportional function focuses more on the flexible derating.

[0052] In one embodiment, the target total power is determined as follows: a second difference between the value 1 and a preset coefficient is calculated, and a third product of the second difference and a correction coefficient is calculated, with the sum of the third product and the preset coefficient used as a comprehensive adjustment factor; the original power is multiplied by the comprehensive adjustment factor to obtain an intermediate power reference value; a third difference between the intermediate power reference value and the target total power of the previous control cycle is calculated; the third difference is subjected to upper and lower limit processing using a preset maximum power change rate to obtain a limited power change amount; and the sum of the limited power change amount and the target total power of the previous control cycle is used as the target total power at the current moment.

[0053] Multiplying the correction factor directly to the original power may cause a step change in the control signal. For example, when the propeller suddenly emerges from the water, the correction factor may drop from 1 to 0.2 in 0.1 seconds. If the power is adjusted directly, the huge current surge will trigger the overcurrent protection of the frequency converter or cause the grid voltage to flicker. Furthermore, if the power is completely cut off in severe sea conditions, the ship may lose its rudder function, causing the hull to be subjected to lateral waves and increasing the risk of capsizing.

[0054] Comprehensive regulatory factors ,in, It is a preset coefficient, for example, equal to 0.2, representing the minimum power retention ratio; A is the obtained correction coefficient; the existence of the preset coefficient ensures that the power will not be completely cut off, and the minimum power required to maintain the rudder effect is retained to ensure the ship's survivability in wind and waves.

[0055] Let the target total power of the previous control cycle be... The currently calculated median value is , The change in the received raw power at the current moment. ,Will Limited to Within the range, It is the maximum power change rate, for example, equal to 10% of the rated power change per second.

[0056] Target total power at the current moment Clamp is a limiting function used to limit the change. Limited to Within the range, when the change exist Within the range, the value of the limiting function is equal to the change. When the change Greater than At that time, the value of the limiting function is equal to When the change Less than At that time, the value of the limiting function is equal to .

[0057] Target total output power The curve of change over time is smooth, which not only protects the motor driver from current surges and extends the life of the power module, but also reduces the mechanical stress on the hull structure.

[0058] Figure 2 This is a schematic diagram illustrating the changes in the motion posture index in an embodiment of this application, such as... Figure 2 As shown, the ship's motion attitude index rises in one period and then falls to a lower level in another period.

[0059] Figure 3 This is a schematic diagram illustrating the change in the target total power in the embodiments of this application, such as... Figure 3 As shown, when the ship's motion attitude index rises, in order to avoid the further increase in output power and the further deterioration of the ship's motion attitude index, the output power can be adaptively reduced and maintained within a certain range to keep the ship stable. When the ship's motion attitude index recovers to a lower level, the output power can be restored to the normal level to ensure the ship's power output.

[0060] In one embodiment, the correction module 1200 is further configured to perform the following steps: calculate the derivative of the propulsion motor speed with respect to time to obtain the shaft speed acceleration; when the shaft speed acceleration is greater than a preset acceleration threshold, set the target total power to zero or a preset idle power value until the phase current of the propulsion motor is detected to rise back to a preset current threshold.

[0061] If the electromagnetic torque is not removed in time, the speed will soar with extremely high acceleration. If no intervention is taken, the motor rotor may mechanically disintegrate due to centrifugal force or cause the bearing to burn out. Therefore, the shaft speed acceleration can be calculated in real time. When the shaft speed acceleration is detected to exceed the physical limit, the power command can be forcibly reset to zero or reduced to idle speed.

[0062] When the propeller re-enters the water, the water resistance is applied to the blades instantly, causing the motor speed to drop. At the same time, the change in back electromotive force causes the phase current to rise. When the phase current is detected to rise to the preset current threshold, it means that the load has been restored, the propeller re-engages the water, and the power limit can be lifted to allow the power to slowly climb.

[0063] The determination module 1300 is configured to acquire the health status parameters and internal resistance parameters of each battery pack in multiple parallel battery packs, determine a first allocation value based on the health status parameters, and determine a second allocation value based on the internal resistance parameters.

[0064] The determination module 1300 can read the status data of each battery cluster in real time through the bus communication interface of the battery management system; the SOH (State of Health) of the battery can characterize the current capacity retention rate of the battery, which is usually defined as the ratio of the current maximum available capacity to the factory rated capacity. The SOH can be estimated by the battery management system based on the ampere-hour integral method combined with the open circuit voltage method or the Kalman filter algorithm.

[0065] The internal resistance parameter can be the sum of the ohmic polarization and electrochemical polarization impedances of the battery during the charging and discharging process. The determination module 1300 can estimate the dynamic internal resistance value in real time based on online parameter identification algorithms, such as the recursive least squares method with a forgetting factor.

[0066] The process of determining the first allocation value based on health status parameters aims to achieve aging equilibrium. For a parallel battery pack, the first allocation value can be equal to the result of normalizing the SOH of the battery pack. , The health status parameters of the battery pack to be determined for the first allocation value are as follows: the higher the SOH of the battery pack, the larger the first allocation value will be.

[0067] The second allocation value is determined based on the internal resistance parameter. The process aims to achieve optimal energy efficiency. The second allocation value can be equal to the result of normalizing the reciprocal of the battery pack's internal resistance parameter. , The internal resistance parameter of the battery pack to be determined for the second allocation value is: the smaller the internal resistance of the battery pack, the stronger its conductivity, and the larger the determined second allocation value.

[0068] The allocation module 1400 is configured to determine a dynamic switching factor based on the motion attitude index, and to use the dynamic switching factor to perform a weighted sum of the first allocation value and the second allocation value to obtain the power allocation weight of the battery pack, so as to allocate the target total power to each battery pack according to the power allocation weight.

[0069] In one embodiment, the power allocation weight of the battery pack is determined by: calculating the fourth difference between the value 1 and the dynamic switching factor, multiplying the fourth difference by the first allocation value to obtain a first weighting term, multiplying the dynamic switching factor by the second allocation value to obtain a second weighting term, and using the sum of the first weighting term and the second weighting term as the power allocation weight of the battery pack.

[0070] Battery pack power allocation weight The calculation formula is ,in, This is a dynamic switching factor, with a value range of [value range missing]. , This is the first allocation value corresponding to the battery pack. This is the second allocation value corresponding to the battery pack.

[0071] In one embodiment, the dynamic switching factor is determined as follows: when the motion attitude index is greater than a preset stability threshold, the dynamic switching factor is set to a first preset value that maximizes the proportion of the second weighting term in the power allocation weight; when the motion attitude index is less than or equal to the preset stability threshold, the dynamic switching factor is set to a second preset value that maximizes the proportion of the first weighting term in the power allocation weight.

[0072] The first preset value is between 0.5 and 1. When the motion attitude index is greater than the preset stability threshold, the power allocation weight corresponding to the battery pack with lower internal resistance can be increased, so that the battery pack with lower resistance can undertake more power output tasks and ensure the stable operation of the ship.

[0073] The second preset value is between 0 and 0.5. When the motion posture index is less than or equal to the preset stability threshold, it can increase the power allocation weight corresponding to the battery pack with a larger health status parameter, so that the healthier battery pack can undertake more power output tasks and extend the total service life of multiple battery packs connected in parallel.

[0074] When the ship is in a stable sea state, that is, when the motion attitude index is less than or equal to the preset stability threshold, the propulsion load fluctuates less, and the battery pack operates in a low-rate charging and discharging state. The main technical problem lies in the inconsistency of aging between battery packs.

[0075] If used unevenly for a long period of time, battery packs with lower SOH will fail first, resulting in a significant bottleneck effect in the entire ship's energy storage system. Therefore, the dynamic switching factor can be set to the first preset value that maximizes the proportion of the second weighting term in the power allocation weight, and the power can be allocated according to the SOH ratio, allowing batteries in better health to output higher power, thereby achieving life balance and delaying the retirement time of the entire battery stack.

[0076] When a ship is in more severe sea conditions, i.e. when the motion attitude index is greater than the preset stability threshold, the propulsion motor needs to frequently perform high-power throughput to resist wind and waves and maintain the ship's position. The main technical challenge lies in the thermal safety and voltage stability of the battery system.

[0077] When the battery pack is discharged at a high rate, if a battery with higher internal resistance is allowed to carry a large current, it will cause the battery with higher internal resistance to overheat rapidly. This may trigger a high temperature alarm in the battery management system and cut off the circuit, which may lead to a power outage for the entire ship. High internal resistance will also cause the DC bus voltage to drop instantly, affecting the normal operation of the frequency converter.

[0078] When the motion attitude index is greater than the preset stability threshold, the dynamic switching factor can be set to the second preset value that maximizes the proportion of the first weighting term in the power allocation weight. This allows the battery pack with lower internal resistance to be prioritized to handle these high-frequency, high-current impacts, thus ensuring the survivability and stability of the ship's power system.

[0079] Figure 4 This is a schematic diagram illustrating the weights assigned to different battery packs in an embodiment of this application, as shown below. Figure 4 As shown, it can allocate matching weights according to the actual conditions of the ship and the actual conditions of different battery packs, so as to achieve adaptive distribution of total output power in different battery packs.

[0080] In one embodiment, allocating the target total power to each battery pack according to the power allocation weight includes: taking the sum of the power allocation weights of all parallel battery packs as the total weight value; calculating the proportion of the power allocation weight of each battery pack to the total weight value to obtain the normalized allocation coefficient of each battery pack; calculating the product of the target total power and the normalized allocation coefficient to obtain the final power value that each battery pack should bear; and sending the final power value to the battery management unit corresponding to each battery pack for execution.

[0081] After determining the final power value that each battery pack should bear, the instruction can be sent to the corresponding converter or inverter and other actuators. After receiving the instruction, each actuator can adjust the output current through the internal voltage loop and current loop to control the corresponding battery pack to respond according to the corresponding final power value.

[0082] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only.

[0083] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A ship multi-mode energy management and adaptive load allocation system, characterized in that, include: The acquisition module is configured to acquire the ship's surface speed, propulsion motor speed, pitch rate and heave acceleration, and determine the slip parameters based on the surface speed, propulsion motor speed and propeller pitch, so as to determine the first attenuation term by using the deviation of the slip parameters from the preset slip rate. The correction module is configured to determine the motion attitude index using the pitch angular velocity and heave acceleration, and determine the second attenuation term based on the motion attitude index. The first product of the first attenuation term and the second attenuation term is used as the correction coefficient. The target total power is obtained by constraining the received raw power using the correction coefficient. The determination module is configured to acquire the health status parameters and internal resistance parameters of each battery pack in multiple parallel battery packs, determine a first allocation value based on the health status parameters, and determine a second allocation value based on the internal resistance parameters. The allocation module is configured to determine the dynamic switching factor based on the motion attitude index, and use the dynamic switching factor to perform a weighted sum of the first allocation value and the second allocation value to obtain the power allocation weight of the battery pack, so as to allocate the target total power to each battery pack according to the power allocation weight. The motion attitude index is determined in the following way: the second ratio of the pitch angular velocity to a preset pitch angular velocity threshold is taken as the pitch component, and the third ratio of the heave acceleration to a preset heave acceleration threshold is taken as the heave component. Determine the sum of the squares of the pitch component and the heave component, and use the arithmetic square root of the sum of squares as the motion attitude index. The first attenuation term is obtained by processing the deviation of the slip parameter relative to the preset slip rate using an exponential attenuation function, and the first attenuation term is negatively correlated with the deviation; The second decay term is obtained by processing the motion posture index using an inverse proportional function.

2. The ship multi-mode energy management and adaptive load allocation system according to claim 1, characterized in that, The slip parameter is determined in the following way: The theoretical advance speed is obtained by multiplying the propulsion motor speed by the second product of the propeller's geometric pitch and using the larger of the theoretical advance speed and the preset positive value as the denominator. The first ratio between the water speed and the denominator is determined, and the first difference between 1 and the first ratio is used as the slip parameter.

3. The ship multi-mode energy management and adaptive load allocation system according to claim 1, characterized in that, The target total power is determined in the following way: Calculate the second difference between the value 1 and the preset coefficient, and calculate the third product of the second difference and the correction coefficient, so that the sum of the third product and the preset coefficient is used as the comprehensive adjustment factor; The intermediate power reference value is obtained by multiplying the original power by the comprehensive adjustment factor; Calculate the third difference between the intermediate power reference value and the target total power of the previous control cycle; The third difference is subjected to upper and lower limit processing using a preset maximum power change rate to obtain the limited power change amount; The sum of the constrained power change and the target total power of the previous control cycle is taken as the target total power at the current moment.

4. The ship multi-mode energy management and adaptive load allocation system according to claim 1, characterized in that, The acquisition module is also configured to perform the following steps: Water depth data is obtained by a depth sounder, and a fourth ratio of the water depth data to the ship's draft is calculated. When the fourth ratio is less than a preset ratio threshold, the preset slip rate used to calculate the first attenuation term is replaced with a preset shallow water correction value. The shallow water correction value is greater than the preset slip rate setting value when the ship is navigating in deep water.

5. The ship multi-mode energy management and adaptive load allocation system according to claim 1, characterized in that, The correction module is also configured to perform the following steps: The shaft speed acceleration is obtained by calculating the derivative of the propulsion motor speed with respect to time. When the shaft speed acceleration is greater than the preset acceleration threshold, the target total power is set to zero or the preset idle power value until the phase current of the propulsion motor is detected to rise back to the preset current threshold.

6. The ship multi-mode energy management and adaptive load allocation system according to claim 1, characterized in that, The first allocation value is positively correlated with the health status parameter, and the second allocation value is negatively correlated with the internal resistance parameter; the power allocation weight of the battery pack is determined in the following way: Calculate the fourth difference between the value 1 and the dynamic switching factor, multiply the fourth difference by the first allocation value to obtain the first weighting term, multiply the dynamic switching factor by the second allocation value to obtain the second weighting term, and use the sum of the first weighting term and the second weighting term as the power allocation weight of the battery pack.

7. The ship multi-mode energy management and adaptive load allocation system according to claim 6, characterized in that, The dynamic switching factor is determined in the following way: When the motion posture index is greater than the preset stability threshold, the dynamic switching factor is set to the first preset value that maximizes the proportion of the second weighting term in the power allocation weight. When the motion posture index is less than or equal to the preset stability threshold, the dynamic switching factor is set to the second preset value that maximizes the proportion of the first weighting term in the power allocation weight.

8. The ship multi-mode energy management and adaptive load allocation system according to claim 1, characterized in that, The target total power is allocated to each battery pack according to the power allocation weight, including: The total weight value is the sum of the power distribution weights of all battery packs connected in parallel. Calculate the proportion of the power allocation weight of each battery pack to the total weight value to obtain the normalized allocation coefficient of each battery pack. Calculate the product of the target total power and the normalized allocation coefficient to obtain the final power value that each battery pack should bear. Send the final power value to the battery management unit corresponding to each battery pack for execution.

Images