A battery pack energy management method, electronic device and watercraft

Abstract

The application discloses a battery pack energy management method, an electronic device and a ship, relates to the field of battery management, and comprises the following steps: determining a comprehensive difference value between two battery packs according to an accumulated discharge energy value and a health state value of each battery pack, and the comprehensive difference value representing a cumulative use difference degree between the two battery packs. In the case that the comprehensive difference value meets an active balancing condition, an active balancing strategy corresponding to a current operation mode of a hybrid power system is executed to reduce the comprehensive difference value. The application accurately represents the cumulative use difference between the battery packs by using the double-parameter comprehensive criterion of the accumulated discharge energy value and the health state value, and executes the targeted active balancing strategy according to the pure electric or hybrid mode, so that the overall use life of the battery packs is effectively prolonged.

Description

Technical Field

[0001] This application relates to the field of battery management technology, and more particularly to a battery pack energy management method, electronic equipment, and vessel. Background Technology

[0002] With the continuous development of energy technology, hybrid power systems have been widely used in ships, vehicles, and other fields. In the marine sector, range-extended marine electrical control cabinets typically employ a dual architecture with independent battery packs and generator sets on the port and starboard sides, respectively. Each side operates independently, providing power to the ship's propulsion system and daily loads. During long-term operation, the cumulative usage difference between the two battery packs gradually amplifies, and the accumulated errors accumulate. Ultimately, this causes one battery pack to reach its discharge limit prematurely or age rapidly and become inoperable, while the other battery pack still has remaining capacity. This forces the entire ship to operate at reduced power or even cease operations, severely impacting the ship's availability and the overall lifespan of the battery packs. Summary of the Invention

[0003] In view of the above problems, this application provides a battery pack energy management method, electronic device, and vessel to maintain the balance among battery packs and effectively extend the overall service life of the battery pack. The specific solution is as follows:

[0004] The first aspect of this application provides a battery pack energy management method, including:

[0005] Based on the cumulative discharge energy value and health status value of each battery pack, a comprehensive difference value between the two battery packs is determined, which characterizes the degree of cumulative usage difference between the two battery packs.

[0006] If the overall difference value meets the active balancing condition, an active balancing strategy corresponding to the current operating mode of the hybrid power system is executed to reduce the overall difference value.

[0007] In one possible implementation, determining the overall difference value between the two battery packs based on the cumulative discharge energy value and health status value of each battery pack includes:

[0008] Based on W Diff =k1×(W tolF - W tolR )+ k2×(SOH tolF - SOH tolR ), to obtain the comprehensive difference value; W Diff For the comprehensive difference value, W tolF W represents the cumulative discharge energy of the first battery pack. tolR The cumulative discharge energy value of the second battery pack, SOH tolF The state of health (SOH) value of the first battery pack.tolR The health status value of the second battery pack is given by k1, which is the first weighting coefficient, and k2 is the second weighting coefficient.

[0009] In one possible implementation, when the current operating mode is pure electric mode, executing an active balancing strategy corresponding to the current operating mode of the hybrid power system to reduce the overall difference value includes:

[0010] The target battery pack is determined based on the remaining power of each battery pack and the first remaining power threshold.

[0011] Adjust the power distribution ratio of the target battery pack to the auxiliary load to change the discharge rate of each of the two battery packs.

[0012] In one possible implementation, adjusting the power allocation ratio of the target battery pack to provide electrical energy to the auxiliary load, thereby changing the discharge rate of the two battery packs, includes:

[0013] A power limit value is sent to the power converter electrically connected to the auxiliary load to constrain the output power of one power converter, and the other power converter supplements the remaining power required by the auxiliary load; or,

[0014] The target frequency of the power converter is controlled based on the droop characteristic curve between active power and frequency to adjust the power distribution ratio.

[0015] In one possible implementation, when the current operating mode is hybrid mode, executing an active balancing strategy corresponding to the current operating mode of the hybrid system to reduce the overall difference value includes:

[0016] The power adjustment direction of the generator set is determined based on the relationship between the current load rate of the generator set and the preset economic operating range.

[0017] The output power of the generator set is adjusted according to the power adjustment direction so that the generator set approaches the preset economic operating range, and at least one of the two battery packs is controlled to charge or discharge in order to reduce the overall difference value.

[0018] In one possible implementation, adjusting the output power of the generator set according to the power adjustment direction to bring the generator set closer to the preset economic operating range, and controlling at least one of the two battery packs to charge or discharge to reduce the overall difference value, includes:

[0019] When the current load rate is lower than the first preset threshold, the generator set is controlled to increase its output power to approach the preset economic operating range. Based on the difference between the increased output power of the generator set and the current output power, the target charging current is calculated, and the battery pack with the larger cumulative discharge energy value among the two battery packs is controlled to charge with the target charging current.

[0020] If the target charging current is greater than the maximum charging current allowed by the battery pack with the larger cumulative discharge energy value, the charging power target value of the battery pack with the larger cumulative discharge energy value is reduced by a preset step size, and the target charging current is recalculated based on the reduced output power target value until the target charging current is not greater than the maximum charging current.

[0021] In one possible implementation, the battery pack energy management method further includes:

[0022] When at least one of the two battery packs reaches the preset upper limit of state of charge, the active balancing strategy is exited and the comprehensive difference value is recorded so that after the hybrid power system switches to pure electric mode, the battery pack with the larger cumulative discharge energy value is prioritized to supply power to the auxiliary load.

[0023] In one possible implementation, adjusting the output power of the generator set according to the power adjustment direction to bring the generator set closer to the preset economic operating range, and controlling at least one of the two battery packs to charge or discharge to reduce the overall difference value, further includes:

[0024] When the current load rate is higher than the second preset threshold, the generator set is controlled to reduce its output power to approach the preset economic operating range. Based on the difference between the current output power of the generator set and the reduced output power, the target discharge current is calculated, and the battery pack with the smaller cumulative discharge energy value among the two battery packs is controlled to discharge with the target discharge current.

[0025] A second aspect of this application provides a computer program product including computer-readable instructions that, when executed on an electronic device, cause the electronic device to implement the battery pack energy management method of the first aspect or any implementation thereof.

[0026] A third aspect of this application provides an electronic device, comprising at least one processor and a memory connected to the processor, wherein:

[0027] The memory is used to store computer programs;

[0028] The processor is used to execute the computer program so that the electronic device can implement the battery pack energy management method of the first aspect or any implementation thereof.

[0029] A fourth aspect of this application provides a computer storage medium carrying one or more computer programs, which, when executed by an electronic device, enable the electronic device to implement the battery pack energy management method described in the first aspect or any implementation thereof.

[0030] By employing the aforementioned technical solution, the battery pack energy management method provided in this application determines a comprehensive difference value based on the cumulative discharge energy value and health status value of each battery pack, and uses this comprehensive difference value as the trigger criterion for active balancing. The cumulative discharge energy value reflects the total historical cumulative discharge of the battery pack since it was put into use, accurately characterizing the long-term usage of the battery pack. The health status value reflects the current aging level of the battery pack, correcting for lifespan differences between battery packs caused by uneven temperature distribution, individual cell failures, etc., making the balancing decision closer to the actual state of the battery pack. By incorporating both cumulative discharge energy and health status into the comprehensive difference value, the degree of difference between the two battery packs can be comprehensively assessed from two orthogonal dimensions: historical cumulative usage and current health status. This avoids misjudgment based on a single parameter and effectively prevents premature aging and failure of one battery pack due to excessive cumulative usage. Finally, the corresponding active balancing strategy is executed according to the current operating mode of the hybrid power system, adapting to the differences in energy flow topology and control logic under different operating modes, improving the targeting and effectiveness of the balancing strategy, thereby effectively extending the overall lifespan of the battery pack and preventing the impact on system availability due to premature failure of one battery pack. Attached Figure Description

[0031] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0032] Figure 1 A flowchart of a battery pack energy management method provided in this application;

[0033] Figure 2 A schematic diagram of the system architecture of a dual-battery-pack range-extended marine electrical control cabinet provided in this application;

[0034] Figure 3 The control flowchart of the active balancing strategy in pure electric mode provided in this application;

[0035] Figure 4A schematic diagram of the universal characteristic curve of the engine provided for this application;

[0036] Figure 5 The control flowchart for the active balancing strategy in hybrid mode provided in this application;

[0037] Figure 6 This is a structural diagram of an electronic device provided in this application. Detailed Implementation

[0038] The embodiments of this application are described below with reference to the accompanying drawings. The terminology used in the implementation section of this application is for explaining specific embodiments only and is not intended to limit the scope of this application.

[0039] As will be known to those skilled in the art, with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0040] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0041] Current battery pack balancing control primarily relies on State of Charge (SOC). For example, using the SOC variance, volatility, and battery life of each energy storage battery pack as optimization objectives, and the number of charge / discharge state switching cycles and power allocation magnitude as optimization variables, a genetic algorithm is employed to obtain the optimal solution for energy storage system control, thereby achieving SOC regulation of the energy storage power station's battery packs. However, the aforementioned existing technologies have the following drawbacks:

[0042] First, using State of Charge (SOC) alone as a criterion for equalization cannot characterize the long-term cumulative differences in battery pack usage. SOC reflects the percentage of the battery's current remaining charge relative to its total capacity; it is an instantaneous state quantity. In a dual-battery pack system, even if the two battery packs have the same SOC at a given moment, their historical cumulative discharge amounts may differ significantly. One battery pack may bear the primary power supply task for a long time, experiencing more charge-discharge cycles, while the other battery pack may remain in a standby state for an extended period. This difference in cumulative usage cannot be reflected by SOC, but it is precisely the root cause of the asynchronous degradation of battery pack lifespan.

[0043] Second, the differences in State of Health (SOH) among battery packs are not fully considered. In actual operating conditions, due to factors such as uneven temperature distribution, manufacturing inconsistencies in individual cells, and localized faults, the aging rates of different battery packs often differ. Existing technologies use ideal parameters such as rated battery capacity as inputs for battery life estimation, ignoring the impact of SOH on the battery's usable capacity and remaining lifespan, leading to a disconnect between balancing decisions and the actual battery state.

[0044] Third, there is no differentiation in balancing strategies for different operating modes. In range-extended hybrid systems, there are two operating states: pure electric mode and hybrid mode. In pure electric mode, the battery pack is the sole energy source. In hybrid mode, the generator and battery pack share power, resulting in fundamentally different energy flow topologies and control logic. Current technology does not develop differentiated balancing strategies for these different operating modes.

[0045] To address the aforementioned problems, this application provides a battery pack energy management method. The battery pack energy management method of this application embodiment will be described in detail below with reference to the accompanying drawings.

[0046] In the description of this application, a battery pack refers to an energy storage unit composed of multiple individual cells connected in series and / or in parallel, and has an independent battery management system (BMS).

[0047] Cumulative discharge energy value: refers to the total amount of electrical energy released by the battery pack since it was put into use. It is calculated and recorded in real time by the BMS through current integration and voltage sampling.

[0048] State of Health (SOH): This parameter characterizes the degree of performance degradation of the battery pack relative to its brand-new state. It is obtained by the BMS through a comprehensive evaluation based on methods such as internal resistance detection, capacity testing, and cycle count statistics.

[0049] State of Charge (SOC): refers to the percentage of the battery's current remaining charge relative to its total capacity. Active balancing condition refers to the comprehensive difference value judgment condition that triggers the active balancing function.

[0050] Hybrid power system: refers to an energy system that simultaneously incorporates two power sources: a generator set (fuel-fired power generation) and a battery pack (energy storage for power supply). Pure electric mode refers to the operating mode powered solely by the battery pack. Hybrid mode refers to the operating mode powered jointly by the generator set and the battery pack. The preset economic operating range refers to the speed-torque operating area in the engine's universal characteristic curve where the fuel consumption rate is below a preset threshold.

[0051] This method can be applied to hybrid power systems with two battery packs, such as dual battery pack systems on the port and starboard sides of range-extended ships, dual battery pack systems in energy storage power stations, or dual battery pack systems in electric vehicles.

[0052] like Figure 2 As shown, taking a range-extended electric vessel as an example, the hybrid power system includes two subsystems on the port and starboard sides. Each subsystem includes a battery pack and a generator set. The battery pack is connected to the DC bus (DC 750V) via a DC / DC converter. The generator set is connected to the DC bus via an AC / DC converter (rectifier). The DC bus is connected to the propulsion motor via a first DC / AC converter and to the AC switchboard (AC 400V) via a second DC / AC converter (daily frequency converter) to supply power to the vessel's daily loads (auxiliary loads).

[0053] like Figure 1 As shown, the battery pack energy management method provided in this application embodiment may include steps S101 to S102, which are described in detail below.

[0054] Step S101: Based on the cumulative discharge energy value and health status value of each battery pack, determine the comprehensive difference value between the two battery packs. The comprehensive difference value characterizes the degree of cumulative usage difference between the two battery packs.

[0055] In this embodiment, the battery management system monitors the operating parameters of each battery pack in real time. For the port and starboard battery packs, the BMS collects the discharge current of the battery pack through a current sensor and the terminal voltage of the battery pack through a voltage sensor. The discharge current is integrated over time and multiplied by the terminal voltage to obtain the cumulative discharge energy value. The integration time can be from the time the battery pack is put into use to the current time.

[0056] Meanwhile, the BMS comprehensively evaluates the state of health (SOH) of the port battery pack based on parameters such as internal resistance detection, usable capacity testing, and charge / discharge cycle count statistics. In this embodiment, the cumulative discharge energy value is expressed in kilowatt-hours (kWh), and the SOH value is expressed as a percentage (%). The SOH of a brand-new battery is 100%, which gradually decreases with use and aging.

[0057] Based on this, the weighted linear formula is used to calculate the comprehensive difference value W. Diff :

[0058] W Diff =k1×(W tolF - W tolR )+ k2×(SOH tolF - SOH tolR );

[0059] Wherein, k1 is the first weighting coefficient, and k2 is the second weighting coefficient. The values ​​of k1 and k2 are pre-calibrated based on the type, capacity, and application scenario of the battery pack. In some specific implementations, both k1 and k2 are positive values, and k1 + k2 = 1. For example, for lithium iron phosphate battery packs, k1 = 0.6 and k2 = 0.4 can be used; for ternary lithium battery packs, k1 = 0.7 and k2 = 0.3 can be used. Of course, for other application scenarios, the first and second weighting coefficients can be set to coefficients greater than 1, that is, the sum of the two weighting coefficients is greater than 1. The specific values ​​of the weighting coefficients can be adjusted according to the actual operating conditions, and this application does not limit them.

[0060] In practical applications, the comprehensive difference value W Diff When positive, it indicates that the cumulative usage of the port side battery pack (considering both cumulative discharge energy and health status) is greater than that of the starboard side battery pack. W Diff A negative value indicates that the cumulative usage of the starboard battery pack is greater than that of the port battery pack. In summary, W... Diff The larger the absolute value, the greater the difference in cumulative usage between the two battery packs.

[0061] The calculation method of this comprehensive difference value unifies two physical quantities with different dimensions, namely the cumulative discharge energy difference (historical cumulative usage difference) and the health status difference (current aging degree difference), into a comparable value through a weighting coefficient, providing a quantitative basis for subsequent threshold judgment.

[0062] Step S102: If the comprehensive difference value meets the active balancing condition, execute the active balancing strategy corresponding to the current operating mode of the hybrid power system to reduce the comprehensive difference value.

[0063] In this embodiment, the active balancing condition can be W.Diff the absolute value of is greater than a preset difference threshold W thd , that is |W Diff |> W thd . The preset difference threshold W thd may be preset according to the rated capacity of the battery pack, the allowed unbalance degree and the accuracy requirement of the control system.

[0064] In some specific implementations, the active equalization condition has a hysteresis characteristic, including a start threshold W_thd_start and an exit threshold W_thd_exit, where W_thd_exit<W_thd_start. When |W Diff |>W_thd_start, the active equalization is started, and when |W Diff |<W_thd_exit, the active equalization is exited. The setting of the hysteresis characteristic can avoid frequent start and stop of the equalization function caused by small fluctuations of the comprehensive difference value near the threshold, and improve the stability and reliability of the system.

[0065] In this embodiment, the current operation modes of the hybrid power system include a pure electric mode and a hybrid mode. The system selects a corresponding active equalization strategy according to the current operation mode.

[0066] If the current mode is the pure electric mode, the active equalization strategy for the pure electric mode is executed. If the current mode is the hybrid mode, the active equalization strategy for the hybrid mode is executed.

[0067] Through the above steps, this embodiment realizes energy management of the battery pack based on a dual-parameter comprehensive criterion of the cumulative discharge energy value and the state of health value. Compared with the solution in the prior art that only uses SOC as the equalization criterion, the technical solution of this embodiment can accurately characterize the degree of cumulative usage difference between two battery packs, and effectively avoid the problem of premature failure of a single-side battery pack caused by the accumulated SOC error. At the same time, by selecting the corresponding active equalization strategy according to the current operation mode, it can adapt to the differences of energy flow topology and control logic under different working modes, and improve the pertinence and effectiveness of the equalization strategy. The overall service life of the battery pack is effectively prolonged, and the system availability is prevented from being affected by the premature failure of the single-side battery pack.

[0068] In some embodiments, the above active equalization strategy for the pure electric mode may specifically include the following processing procedures:

[0069] In pure electric mode, the generator set is not operating, and the battery pack is the sole energy source. At this time, the first and second DC / DC converters, where the battery packs are located, operate as voltage sources, responsible for maintaining a stable DC bus voltage. The propulsion loads on both sides (port and starboard propulsion motors) require equal power to maintain thrust balance between the port and starboard sides; therefore, balancing between the battery packs cannot be achieved by adjusting the power distribution of the propulsion loads. The daytime loads (auxiliary loads) draw power from the DC bus through the third DC / AC converter (daytime inverter), and their power distribution has a certain degree of adjustability.

[0070] The specific equilibrium steps include:

[0071] Step S21: Determine the target battery pack based on the remaining power of each battery pack and the first remaining power threshold.

[0072] State of charge (SOC) reflects the percentage of the battery's current remaining capacity relative to its total capacity. The BMS monitors the remaining capacity of the port and starboard battery packs in real time.

[0073] Based on the calculated overall difference value, it can be determined which battery pack has a greater cumulative usage. For example, when W Diff When W > 0, it indicates that the cumulative usage of the port battery pack is greater than that of the starboard battery pack, meaning the port battery pack discharges more and ages more severely. In this case, the starboard battery pack (the one with less cumulative usage) should be prioritized to handle more power supply tasks. Diff When the value is less than 0, it indicates that the cumulative usage of the starboard battery pack is greater than that of the port battery pack. In this case, the port battery pack should be given priority to handle more power supply tasks.

[0074] For example, when W Diff When W_Diff > 0, the target battery pack is the starboard battery pack (the side with lower cumulative discharge energy and higher SOH). When the SOC_R of the starboard battery pack is greater than the first remaining capacity threshold SOC_thd, active balancing is initiated, prioritizing the starboard battery pack to supply power to the auxiliary load. When W_Diff < 0, the target battery pack is the port battery pack. When the SOC_F of the port battery pack is greater than the first remaining capacity threshold SOC_thd, active balancing is initiated, prioritizing the port battery pack to supply power to the auxiliary load.

[0075] The first remaining charge threshold, SOC_thd, is a safety protection threshold used to prevent damage to the target battery pack due to over-discharge. For example, even if the overall difference value is large, active balancing will not be initiated to ensure the basic safe charge level of the battery pack.

[0076] Step S22: Adjust the power distribution ratio of the target battery pack to the auxiliary load to change the discharge rate of each of the two battery packs.

[0077] After determining the target battery pack, the power allocation ratio of the target battery pack to the auxiliary load is adjusted so that the target battery pack undertakes more power supply tasks for the auxiliary load, thereby increasing the discharge rate and cumulative discharge of the target battery pack and reducing the overall difference between the two battery packs.

[0078] For example, in pure electric mode, the port battery pack is connected to the DC bus via a first DC / DC converter, and the starboard battery pack is connected to the DC bus via a second DC / DC converter. The DC bus then supplies power to the auxiliary load via a third DC / AC converter (daily frequency converter). To adjust the power distribution ratio, one or a combination of the following two methods can be used.

[0079] Power limiting scheme: A power limiting value is sent to the power converter (i.e., the third DC / AC converter) that is electrically connected to the auxiliary load to constrain the output power of one power converter, and the other power converter supplements the remaining power required by the auxiliary load.

[0080] For example, when the target battery pack is the starboard battery pack, the system sends a power limit value to the second DC / DC converter corresponding to the starboard battery pack, increasing its output power setting and enabling it to handle more DC bus power supply tasks. Simultaneously, it sends a power limit value to the first DC / DC converter corresponding to the port battery pack, decreasing its output power setting. Since the AC distribution board needs to maintain constant voltage and frequency, when the output power of one power converter is limited, the other power converter will automatically supplement the remaining power required by the auxiliary load, thus achieving a natural redistribution of power.

[0081] Droop control scheme: Based on the droop characteristic curve between active power and frequency, the target frequency of the power converter is controlled to adjust the power distribution ratio.

[0082] For example, the active power-frequency droop coefficient of each DC / DC converter can be pre-calibrated. When the discharge power of the target battery pack needs to be increased, the target frequency of the DC / DC converter on that side is adjusted so that it can handle more power output according to the droop characteristic curve. Real-time communication between the converters is not required; power allocation can be automatically achieved simply by detecting the DC bus frequency (or voltage). This droop control scheme has the advantages of no communication required and good redundancy, making it suitable for scenarios with high reliability requirements.

[0083] Step S23: Exit active balancing.

[0084] Active balancing ends when the absolute value of the overall difference is less than the exit threshold, or when the SOC of the target battery pack is lower than the first remaining charge threshold. After exiting, each power converter returns to normal operation.

[0085] In pure electric mode, power balancing is achieved by adjusting the power distribution ratio on the auxiliary load side, effectively changing the discharge rate of each battery pack without affecting the total power of the driving load. By prioritizing the battery pack with lower cumulative usage and higher SOC to undertake more auxiliary load power supply tasks, peak shaving and valley filling active balancing is achieved, making the cumulative discharge of the two battery packs tend to be consistent.

[0086] For example, refer to Figure 3 As shown, the control scheme in pure electric mode is as follows:

[0087] 1) When |W Diff |>W thd And the SOC of the corresponding battery pack is greater than the threshold SOC. thd At that time, active balancing is initiated.

[0088] 2) Since the inverter (DC / DC) where the battery is located is a voltage source (to maintain the DC bus voltage stability), and both sides of the propulsion require the same power to maintain the port and starboard sides, the power distribution of the battery inverter is achieved by adjusting the output power of the daily inverter DCAC (an inverter connected to AC 400V). The power limitation of the current inverter is achieved by adjusting the target voltage and target frequency to realize the power distribution between the two daily inverters.

[0089] 3) When |W Diff |≤W thd Or SOC is less than the threshold SOC thd At that time, the active equilibrium is exited.

[0090] In other embodiments, the active balancing strategy in hybrid mode may specifically include the following processing steps (see also [reference]). Figure 5 (as shown)

[0091] In hybrid mode, the generator set and battery pack share the power supply. The generator set is connected to the DC bus via an AC / DC converter (rectifier) ​​and operates as a voltage source, responsible for supporting the DC bus voltage. The battery pack is connected to the DC bus via a DC / DC converter and operates as a current source, achieving peak shaving and valley filling. It charges and stores energy when the generator set has excess power and discharges to supplement energy when the generator set has insufficient power. The control characteristics of the battery pack as a current source in hybrid mode are fundamentally different from those as a voltage source in pure electric mode, therefore, a differentiated active balancing strategy is required.

[0092] Hybrid mode active balancing strategy may include the following steps:

[0093] Step S31: Determine the power adjustment direction of the generator set based on the relationship between the current load rate of the generator set and the preset economic operating range.

[0094] The energy management controller obtains the current output power P_gen of the generator set and calculates the current load rate η = P_gen / P_rated × 100% based on the rated power P_rated of the generator set.

[0095] The preset economic operating range is determined based on the engine's universal characteristic curve. For example... Figure 4 As shown, the horizontal axis of the engine's universal characteristic curve represents engine speed, and the vertical axis represents engine torque. The contour lines on the curve represent fuel consumption rate (unit: grams per kilowatt-hour, g / kWh). The region with the lowest fuel consumption rate is the optimal economic zone. The relationship between engine output power and speed / torque is: P = n × T / 9550, where P is power (unit: kilowatts), n is speed (unit: revolutions per minute), and T is torque (unit: Newton-meters). Based on the current power generation P_gen, the engine's speed and torque points under the current operating conditions can be calculated, and it can then be determined whether these points fall within the preset economic operating range.

[0096] For example, a generator set has a rated power of 500kW and an optimal economic load rate of 85% (that is, the fuel consumption rate is lowest when the output power is 425kW). The preset economic operating range is 80%~90% load rate.

[0097] Compare the current load rate η with the preset economic operating range [η_low, η_high]:

[0098] If η < η_low (e.g., η < 80%), it indicates that the generator set load rate is low and the engine is operating in a low-load area with poor economic efficiency. The direction of power adjustment should be to increase the power generation.

[0099] If η > η_high (e.g., η > 90%), it indicates that the generator set load rate is too high, the engine is working in the high load area, which also deviates from the optimal economic zone. The power adjustment direction should be to reduce the power generation.

[0100] If η_low ≤ η ≤ η_high, it means that the generator set is already operating within the preset economic operating range and there is no need to adjust the power generation for economic purposes, but it can be fine-tuned based on the balance demand.

[0101] Step 32: Adjust the generator set output power according to the power adjustment direction, and control the battery pack to charge or discharge.

[0102] Charging strategy when the load rate is low:

[0103] When the current load rate of the generator set is lower than the first preset threshold η_low (e.g., η < 80%), the generator set is controlled to increase its output power to approach the preset economic operating range, while the battery pack with the larger cumulative discharge energy value is charged.

[0104] For example, the optimal load rate for the preset economic operating range is η_opt (e.g., 85%), and the current load rate is η_cur (e.g., 50%). Calculate the required power increase ΔP = (η_opt - η_cur) / 100 × P_rated. Using the above values ​​as an example, ΔP = (85% - 50%) / 100 × 500kW = 175kW. Control the generator set to increase its output power ΔP, raising it from the current load rate of 50% to the optimal load rate of 85%.

[0105] The increased output power ΔP from the generator set is not consumed by the driving or auxiliary loads, but is used to charge the battery packs. The target charging current I_chg_target = ΔP / U_bus is calculated based on ΔP and the current DC bus voltage U_bus. The battery pack with the larger accumulated discharge energy is charged at the target charging current I_chg_target.

[0106] If the target charging current I_chg_target is greater than the maximum allowable charging current I_chg_max of the battery pack, the generator set output power target value is gradually reduced according to the preset step size, and the target charging current is recalculated based on the reduced output power target value until the target charging current is not greater than the maximum charging current.

[0107] For example, with a maximum charging current I_chg_max = 200A and a current bus voltage U_bus = 700V, the calculated I_chg_target = 175kW / 700V = 250A, which is greater than I_chg_max = 200A. At this point, the generator output power target is reduced by a preset step size (e.g., 5%), from the optimal load rate of 85% to the suboptimal load rate of 80%. The recalculated ΔP = (80% - 50%) / 100 × 500kW = 150kW, and I_chg_target = 150kW / 700V ≈ 214A, still greater than 200A. Further reduction to 75% yields ΔP = (75% - 50%) / 100 × 500kW = 125kW, and I_chg_target = 125kW / 700V ≈ 179A, less than 200A, thus meeting the battery pack's charging current limit. At this time, the generator set is controlled to increase its output power to 75% of the load rate, and the battery pack with a large cumulative discharge energy value is charged with a current of 179A.

[0108] This stepped current limiting verification mechanism effectively ensures the charging safety of the battery pack and prevents irreversible damage to the battery caused by overcharging current.

[0109] Discharge strategy when the load rate is high:

[0110] When the current load rate of the generator set is higher than the second preset threshold η_high (e.g., η > 90%), the generator set is controlled to reduce its output power to approach the preset economic operating range, while the battery pack with the smaller cumulative discharge energy value is controlled to discharge.

[0111] For example, the current load rate is 95%, and the optimal load rate is 85%. The required power reduction ΔP = (η_cur - η_opt) / 100 × P_rated = (95% - 85%) / 100 × 500kW = 50kW. The generator set is then controlled to reduce its output power ΔP from the current load rate of 95% to the optimal load rate of 85%.

[0112] The reduced output power ΔP of the generator set is compensated by the discharge of the battery packs to maintain the power balance of the DC bus. The target discharge current I_dis_target = ΔP / U_bus is calculated based on ΔP and the current DC bus voltage U_bus. The battery pack with the smaller cumulative discharge energy (i.e., lower cumulative usage) is controlled to discharge at the target discharge current I_dis_target.

[0113] Similarly, if the target discharge current is greater than the maximum allowable discharge current of the battery pack, the output power of the generator set will be gradually reduced according to the preset step size until the target discharge current is not greater than the maximum discharge current.

[0114] Step S33: Exit active balancing.

[0115] The conditions for exiting the active balancing mode in hybrid mode include the following:

[0116] (1) When |W Diff |≤W thd At that time, the active equilibrium is exited.

[0117] (2) When the state of charge (SOC) of at least one of the two battery packs reaches the preset upper limit of SOC_thdstp (e.g., 95%), the active balancing strategy is exited to prevent the battery pack from being overcharged.

[0118] (3) When the hybrid system exits the hybrid mode, it exits the active balance.

[0119] When the active balancing is terminated due to the SOC reaching the upper limit, the system records the current comprehensive difference value W_Diff_record so that after the hybrid system switches to pure electric mode, it can prioritize controlling the battery pack with the larger cumulative discharge energy value to supply power to the auxiliary load, thus realizing the cross-mode relay of the balancing strategy.

[0120] In hybrid mode, active balancing is combined with optimized economic operation of the generator set. When the generator set load rate is low, the power output is increased to bring it back to the economic zone, and the excess power is used for charging. When the generator set load rate is high, the power output is reduced to bring it back to the economic zone, and the battery pack discharges to make up for the power shortfall. This two-way adjustment mechanism reduces the overall difference value while keeping the generator set close to the preset economic operating range, thus achieving both active balancing of the battery pack and improving the fuel economy of the generator set. A stepped current limiting verification mechanism further ensures the charging and discharging safety of the battery pack.

[0121] For example, refer to Figure 5 The control scheme for the hybrid mode is as follows:

[0122] 1) When |W Diff |>W thd At that time, active balancing is initiated.

[0123] 2) Calculate whether the engine is operating in the optimal economic zone based on the current power output of the generator set.

[0124] 3) When the generator set load rate is low and the corresponding battery pack SOC is lower than the threshold SOCthdlo, the battery pack charging current is calculated based on the generator set's optimal operating economic zone. When the SOC is higher than the threshold SOCthdstp, active balancing is exited and active balancing is achieved by prioritizing the discharge of the battery pack in pure electric mode.

[0125] 4) When the generator set load rate is high and the corresponding battery pack SOC is higher than the threshold SOCthdhi, calculate the battery pack discharge current based on the generator set's optimal operating economic zone. When |W Diff |≤W thd Or, when exiting hybrid mode, exit active balancing.

[0126] This application uses the total discharge energy during the life cycle and the SOH signal fed back by the BMS to determine whether active balancing is needed, which can improve the accuracy of the judgment. Furthermore, by combining the generator set's optimal operating economic zone with the active balancing function, active balancing can be achieved while also improving the overall economy of the ship.

[0127] This application also provides an electronic device in its embodiments. (See reference...) Figure 6 The diagram illustrates a structural schematic suitable for implementing the electronic devices in the embodiments of this application. The electronic devices in the embodiments of this application may include, but are not limited to, ECU (Electronic Control Unit), VCU (Vehicle Control Unit), MCU (Micro Controller Unit), HCU (Hybrid Control Unit), etc. Figure 6 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0128] refer to Figure 6 As shown, the electronic device includes at least one processor 601 and a memory 602 connected to the processor 601, wherein: the memory is used to store computer programs; the processor 601 is used to execute the computer programs to enable the electronic device to implement the battery pack energy management method as described in the above embodiment.

[0129] This application also provides a computer program product, including computer-readable instructions, which, when executed on an electronic device, cause the electronic device to implement any of the battery pack energy management methods provided in this application.

[0130] This application also provides a computer-readable storage medium that carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement any of the battery pack energy management methods provided in this application.

[0131] This application also provides a vessel that includes the electronic equipment described in the above embodiments.

[0132] It should also be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. In addition, in the device embodiment drawings provided in this application, the connection relationship between modules indicates that they have a communication connection, which can be implemented as one or more communication buses or signal lines.

[0133] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware, or it can be implemented by special-purpose hardware including application-specific integrated circuits, special-purpose CPUs, special-purpose memory, special-purpose components, etc. Generally, any function performed by a computer program can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be diverse, such as analog circuits, digital circuits, or special-purpose circuits. However, for this application, software program implementation is more often the preferred implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a computer floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk, or optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, training equipment, or network device, etc.) to execute the battery pack energy management method described in the various embodiments of this application.

[0134] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product.

[0135] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

Claims

1. A battery pack energy management method, characterized in that, include: Based on the cumulative discharge energy value and health status value of each battery pack, a comprehensive difference value between the two battery packs is determined, which characterizes the degree of cumulative usage difference between the two battery packs. If the overall difference value meets the active balancing condition, an active balancing strategy corresponding to the current operating mode of the hybrid power system is executed to reduce the overall difference value.

2. The battery pack energy management method according to claim 1, characterized in that, The comprehensive difference value between the two battery packs is determined based on the cumulative discharge energy value and health status value of each battery pack, including: Based on W Diff =k1×(W tolF - W tolR )+ k2×(SOH tolF - SOH tolR ), to obtain the comprehensive difference value; W Diff For the comprehensive difference value, W tolF W represents the cumulative discharge energy of the first battery pack. tolR The cumulative discharge energy value of the second battery pack, SOH tolF The state of health (SOH) value of the first battery pack. tolR The health status value of the second battery pack is given by k1, which is the first weighting coefficient, and k2 is the second weighting coefficient.

3. The battery pack energy management method according to claim 1, characterized in that, When the current operating mode is pure electric mode, the execution of the active balancing strategy corresponding to the current operating mode of the hybrid power system to reduce the overall difference value includes: The target battery pack is determined based on the remaining power of each battery pack and the first remaining power threshold. Adjust the power distribution ratio of the target battery pack to the auxiliary load to change the discharge rate of each of the two battery packs.

4. The battery pack energy management method according to claim 3, characterized in that, The adjustment of the power distribution ratio of the target battery pack to the auxiliary load, thereby changing the discharge rate of the two battery packs, includes: A power limit value is sent to the power converter electrically connected to the auxiliary load to constrain the output power of one power converter, and the other power converter supplements the remaining power required by the auxiliary load; or, The target frequency of the power converter is controlled based on the droop characteristic curve between active power and frequency to adjust the power distribution ratio.

5. The battery pack energy management method according to claim 1, characterized in that, When the current operating mode is hybrid mode, the execution of the active balancing strategy corresponding to the current operating mode of the hybrid power system to reduce the overall difference value includes: The power adjustment direction of the generator set is determined based on the relationship between the current load rate of the generator set and the preset economic operating range. The output power of the generator set is adjusted according to the power adjustment direction so that the generator set approaches the preset economic operating range, and at least one of the two battery packs is controlled to charge or discharge in order to reduce the overall difference value.

6. The battery pack energy management method according to claim 5, characterized in that, The adjustment of the generator set's output power according to the power adjustment direction to bring the generator set closer to the preset economic operating range, and the control of at least one of the two battery packs to charge or discharge to reduce the overall difference value, includes: When the current load rate is lower than the first preset threshold, the generator set is controlled to increase its output power to approach the preset economic operating range. Based on the difference between the increased output power of the generator set and the current output power, the target charging current is calculated, and the battery pack with the larger cumulative discharge energy value among the two battery packs is controlled to charge with the target charging current. If the target charging current is greater than the maximum charging current allowed by the battery pack with the larger cumulative discharge energy value, the charging power target value of the battery pack with the larger cumulative discharge energy value is reduced by a preset step size, and the target charging current is recalculated based on the reduced output power target value until the target charging current is not greater than the maximum charging current.

7. The battery pack energy management method according to claim 6, characterized in that, The method further includes: When at least one of the two battery packs reaches the preset upper limit of state of charge, the active balancing strategy is exited and the comprehensive difference value is recorded so that after the hybrid power system switches to pure electric mode, the battery pack with the larger cumulative discharge energy value is prioritized to supply power to the auxiliary load.

8. The battery pack energy management method according to claim 5, characterized in that, The step of adjusting the output power of the generator set according to the power adjustment direction to bring the generator set closer to the preset economic operating range, and controlling at least one of the two battery packs to charge or discharge in order to reduce the overall difference value, further includes: When the current load rate is higher than the second preset threshold, the generator set is controlled to reduce its output power to approach the preset economic operating range. Based on the difference between the current output power of the generator set and the reduced output power, the target discharge current is calculated, and the battery pack with the smaller cumulative discharge energy value among the two battery packs is controlled to discharge with the target discharge current.

9. An electronic device, characterized in that, It includes at least one processor and a memory connected to the processor, wherein: The memory is used to store computer programs; The processor is used to execute the computer program to enable the electronic device to implement the battery pack energy management method as described in any one of claims 1 to 8.

10. A vessel, characterized in that, Including the electronic device as described in claim 9.

Images