Real-time calculation method for dissipation boundary of diesel-electric hybrid power system

Abstract

The invention provides a real-time calculation method for a dissipation boundary of a diesel-electric hybrid power system. The method comprises the steps that the power of a diesel generator, the power of a motor and the SOC of a battery in the diesel-electric hybrid power system are collected, the SOC state factor of the battery, the equivalent fuel consumption conversion coefficient of the battery and the equivalent fuel consumption of the battery are calculated according to collected data, and the minimum sum of the fuel consumption of the diesel generator and the equivalent fuel consumption of the battery serves as the target; the method comprises the following steps: constructing a target function of a dissipation boundary of the diesel-electric hybrid power system, solving the target function to obtain a real-time output power sequence of a diesel generator, a motor and a battery, and calculating a minimum fuel consumption theoretical value of the diesel-electric hybrid power system according to actual fuel consumption power and linear correlation between a diesel generator set power level and the dissipation boundary. And the dissipation boundary of the diesel-electric hybrid power system is obtained. According to the invention, unnecessary fuel consumption can be reduced while stable operation of the system can be ensured, so that the economical efficiency and the operation stability of the system are improved.

Description

Technical Field

[0001] This invention relates to the field of diesel-electric hybrid technology, and in particular to a real-time calculation method for the dissipation boundary of a diesel-electric hybrid system. Background Technology

[0002] Currently, diesel-electric hybrid powertrains demonstrate significant advantages in long-distance and heavy-load transportation, but their efficiency faces challenges due to insufficient adaptability to dynamic operating conditions. Among these challenges, the energy dissipation characteristics of diesel-electric hybrid systems are a core bottleneck restricting overall system efficiency improvement and emission reduction. Traditional research methods typically rely on static or empirical boundaries, making it difficult to accurately characterize the system's real-time energy consumption limits under the transient operating conditions of actual vehicles, leading to conservative or inaccurate energy management strategies. With the development of onboard sensing and real-time computing technologies, online analysis and optimization of the dynamic processes of powertrain systems have become possible.

[0003] To achieve global optimization of the efficiency of diesel-electric hybrid power systems, it is essential to establish a dynamic model that can reflect the maximum allowable energy consumption boundaries of the diesel engine and electric drive unit under different loads, temperatures, and coupling conditions in real time. The core of this dynamic model lies in identifying the transient dissipation boundaries of the system in real time, providing a precise constraint framework for online energy management strategies, thereby guiding power distribution to always operate within the optimal efficiency range.

[0004] Currently, existing diesel-electric hybrid systems primarily focus on adjusting the energy management strategy of the battery to achieve energy distribution and operational status regulation among the power sources in the system. While this approach is simple and easy to operate, it suffers from poor real-time performance and cannot flexibly adjust according to changes in the actual operating status of the vehicle.

[0005] The disadvantages of the existing diesel-electric hybrid power systems mentioned above include: they largely focus on adjusting the energy management strategy of the battery to achieve energy distribution and operational status regulation between the power sources in the system. Although this strategy is simple and easy to operate, it has poor real-time performance and cannot be flexibly adjusted according to changes in the actual operating status of the vehicle. Summary of the Invention

[0006] This invention provides a real-time calculation method for the dissipation boundary of a diesel-electric hybrid power system, so as to effectively ensure that the system can reduce unnecessary fuel consumption while operating stably, thereby improving the system's economy and operational stability.

[0007] To achieve the above objectives, the present invention adopts the following technical solution.

[0008] A real-time calculation method for the dissipation boundary of a diesel-electric hybrid power system includes: Data is collected on the power output of the diesel generator and electric motor, as well as the battery's state of charge (SOC) in the diesel-electric hybrid system. Based on the collected data, the battery SOC state factor is calculated. Battery equivalent fuel consumption conversion factor ; According to the above The above and the real-time power dissipation of the battery Calculate the equivalent fuel consumption of the battery. To minimize the sum of diesel generator fuel consumption and battery equivalent fuel consumption, an objective function for the dissipation boundary of the diesel-electric hybrid power system is constructed, and optimization constraints are set for the objective function. Based on the aforementioned optimization constraints, an optimization algorithm is used to solve the objective function, thereby obtaining the real-time output power sequence of the diesel generator, electric motor, and battery. The actual fuel consumption power of the diesel-electric hybrid power system is then calculated based on the real-time output power sequence of the diesel generator, electric motor, and battery. The actual fuel consumption power of the diesel-electric hybrid system is compared with the historical optimal fuel consumption power threshold. If the actual fuel consumption power is not greater than the historical optimal fuel consumption power threshold, the theoretical minimum fuel consumption value of the diesel-electric hybrid system is calculated based on the linear correlation between the actual fuel consumption power of the diesel-electric hybrid system, the power level of the diesel generator set, and the dissipation boundary. The dissipation boundary of the diesel-electric hybrid system is obtained based on the theoretical minimum fuel consumption value of the diesel-electric hybrid system.

[0009] Preferably, the process involves collecting the power of the diesel generator and electric motor, and the state of charge (SOC) of the battery in the diesel-electric hybrid system, and calculating the battery SOC state factor based on the collected data. Battery equivalent fuel consumption conversion factor ,include: Collect power data of the diesel generator and electric motor, and battery SOC status data in the diesel-electric hybrid system. Then, based on the battery SOC value and a preset optimal SOC value... Calculate the battery SOC state factor Battery equivalent fuel consumption conversion factor ; The calculation formulas are shown in formulas (1) and (2): (1) (2) In formulas (1) and (2), For state factors, For battery efficiency, For diesel generator efficiency, For DC / DC converter efficiency, For the system fuel with low calorific value, , and For standardization.

[0010] Preferably, the method according to the The above and the real-time power dissipation of the battery Calculate the equivalent fuel consumption of the battery. ,include: The sum of the actual fuel consumption of diesel generators and electric motors The calculation formula is shown in Figure (3), which represents the equivalent fuel consumption of the battery. The calculation formula is shown in Figure (4); (3) (4) In formula (3), This refers to the real-time power dissipation of the diesel generator. This refers to the real-time power dissipation of the electric motor. For motor efficiency, , For real-time acquisition / calculation of values; In formula (4), This refers to the real-time power dissipation of the battery. For real-time acquisition / calculation of values.

[0011] Preferably, the objective function for constructing the dissipation boundary of the diesel-electric hybrid power system, with the goal of minimizing the sum of the diesel generator's fuel consumption and the battery's equivalent fuel consumption, and the optimization constraints of the objective function, include: Objective function for constructing the dissipation boundary of a diesel-electric hybrid power system The calculation is shown in formula (5): (5) in, The minimum fuel consumption equivalent to the power loss of a diesel-electric hybrid system at different times; and These represent the fuel consumption of the diesel generator and the electric motor during operation, respectively. It is the equivalent fuel consumption of the power battery during operation. yes The actual fuel efficiency corresponding to the engine output power. ; yes Equivalent fuel consumption due to motor losses. , It is the equivalent fuel consumption rate after dynamic correction of battery charging and discharging power. equal ; The objective function is set with optimization constraints, which include: power / speed limits for each component, upper and lower limits of battery SOC, and battery capacity retention constraints.

[0012] Preferably, the step of solving the objective function using an optimization algorithm based on the optimization constraints to obtain the real-time output power sequence of the diesel generator, electric motor, and battery, and calculating the actual fuel consumption power of the diesel-electric hybrid system based on the real-time output power sequence of the diesel generator, electric motor, and battery, includes: Based on the optimization constraints of the objective function, ensuring that the battery SOC is in a normal state and that the output power and speed of the engine, motor, and battery do not exceed the hardware's tolerance limits, the objective function is solved using an optimization algorithm. Dynamic programming is employed to control the selection of engine output power. The entire solution process uses power balance as a constraint, and the objective function is... As the fuel consumption cost at each step, starting from the last moment of the operating condition, the minimum cumulative cost under each SOC state is calculated in reverse to finally obtain the optimal control sequence starting from the initial SOC. The optimal control sequence is substituted into the actual fuel consumption calculation formula to verify whether it meets the minimum fuel consumption target. If it does not meet the target, it is fed back to the power distribution calculation stage, and the control variables are adjusted and iterated again until the optimal real-time output power sequence of the diesel generator, motor and battery is obtained.

[0013] Preferably, the step of calculating the actual fuel consumption power of the diesel-electric hybrid system based on the real-time output power sequence of the diesel generator, electric motor, and battery includes: The real-time power dissipation of the diesel generator is obtained based on the real-time output power sequence of the diesel generator, electric motor, and battery. Real-time power dissipation of the motor and the real-time power dissipation of the battery Calculate the actual fuel consumption power of the diesel-electric hybrid system. The calculation formula is shown in formula (6): (6)

[0014] Preferably, the step of comparing the actual fuel consumption power of the diesel-electric hybrid system with the historical optimal fuel consumption power threshold, and if the actual fuel consumption power is not greater than the historical optimal fuel consumption power threshold, calculates the theoretical minimum fuel consumption value of the diesel-electric hybrid system based on the linear correlation between the actual fuel consumption power of the diesel-electric hybrid system and the power level of the diesel generator set and the dissipation boundary, and obtains the dissipation boundary of the diesel-electric hybrid system based on the theoretical minimum fuel consumption value of the diesel-electric hybrid system, including: The actual fuel consumption power of the diesel-electric hybrid system is compared with the historical optimal fuel consumption power threshold. If the actual fuel consumption power is greater than the historical optimal fuel consumption power threshold, the power allocation is recalculated, and the real-time output power sequence of the diesel generator, electric motor and battery is recalculated. If the actual fuel consumption power is not greater than the historical best fuel consumption power threshold, based on the actual fuel consumption power of the diesel-electric hybrid system and the linear correlation between the diesel generator set power level and the dissipation boundary, the theoretical minimum fuel consumption value of the diesel-electric hybrid system is calculated. Based on this theoretical minimum fuel consumption value, the dissipation boundary of the diesel-electric hybrid system is obtained, which includes: 1. Dissipated power boundary: Specifically, it can be divided into the upper limit of motor power loss, the upper limit of battery power loss, and the upper limit of total dissipated power. 2. Equivalent fuel consumption rate boundary: Converting dissipated power into equivalent fuel consumption rate, unifying the dimensions with engine fuel consumption rate; 3. Power distribution constraint boundary: From the perspective of power distribution, the output range of each component is limited to indirectly control the power dissipation; the charging and discharging power range of the battery is limited according to the SOC state and the upper limit of the power dissipation. 4. Dynamic correction boundary: A dynamic threshold that is adjusted in real time according to changes in operating conditions and SOC.

[0015] As can be seen from the technical solutions provided by the embodiments of the present invention above, the method of the present invention starts from the internal mechanism of the system. The proposed dissipation boundary function research method can provide the fuel consumption corresponding to the internal loss during the operation of the diesel-electric hybrid power system, and can also provide the real-time adjustment direction of the generator and battery state parameters based on the system operating state.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a diesel-electric multi-source diesel-electric hybrid power system provided in an embodiment of the present invention; Figure 2 This is a flowchart of a real-time calculation method for the dissipation boundary of a diesel-electric hybrid power system provided in an embodiment of the present invention. Figure 3 This is a diagram showing the relationship between the net output power of a motor and the internal losses of a system, provided in an embodiment of the present invention. Figure 4 This is a diagram showing the relationship between internal system losses and fuel consumption, provided in an embodiment of the present invention. Figure 5 This is an embodiment of the present invention providing a relationship between internal system losses and recommended rotational speed; Figure 6 This is a system-recommended speed value and the theoretical minimum fuel consumption provided by an embodiment of the present invention. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0021] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0022] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0023] This invention provides a real-time calculation method for the dissipation boundary of a diesel-electric hybrid power system. The proposed method starts from the internal mechanism of the system. The proposed method for studying the dissipation boundary function can provide the fuel consumption corresponding to the internal losses during the operation of the diesel-electric hybrid power system, and can also provide the real-time adjustment direction of the generator and battery state parameters based on the system operating status.

[0024] The dissipation boundary of a diesel-electric hybrid power system includes the maximum allowable energy consumption boundary of the diesel engine and generator under different loads, temperatures and coupling conditions. The dissipation boundary takes the energy transfer link of the diesel-electric hybrid power system as the core carrier and covers energy dissipation links such as engine mechanical energy-electric energy conversion loss, generator electromagnetic conversion loss and battery equivalent fuel consumption.

[0025] The construction of the dissipation boundary of a diesel-electric hybrid power system is based on the system dynamics equations and electromagnetic equations. It establishes a strong mathematical mapping relationship between each loss element and key operating parameters such as engine speed, generator net output power, and battery state of charge, distinguishing it from traditional methods that rely on empirical fitting or static experimental data. Its core functions are twofold: first, by solving the dissipation boundary objective function in real time, it accurately quantifies the energy loss value of each loss unit and, combined with the engine fuel consumption characteristic curve, derives the equivalent fuel consumption corresponding to the loss; second, leveraging dynamic feedback characteristics, it indicates the system state based on the loss distribution characteristics, thereby clarifying the real-time adjustment direction of parameters such as generator output voltage and current, excitation current, or engine-generator coupling speed.

[0026] A schematic diagram of a diesel-electric multi-source diesel-electric hybrid power system provided in this embodiment of the invention is shown below. Figure 1 As shown, the system includes a diesel generator, an electric motor, a battery, an AC / DC converter, a DC / DC converter, and a load.

[0027] The processing flow of a real-time calculation method for the dissipation boundary of a diesel-electric hybrid power system provided in this embodiment of the invention is as follows: Figure 2 As shown, the process includes: initial data acquisition, SOC (State of Charge) related parameter calculation, objective function construction, optimization constraint setting, power allocation calculation, actual fuel consumption calculation, fuel consumption optimality judgment, power scheme output, and minimum fuel consumption, including the following processing steps: Step S10, Initial Data Acquisition: The system collects real-time data such as diesel generator and electric motor power, battery SOC status, and vehicle load requirements, and outputs real-time operating status data, which includes power, battery SOC value, and load.

[0028] Step S20: Calculation of SOC correlation parameters

[0029] Based on the above battery SOC value and the preset optimal SOC value Calculate the battery SOC state factor Battery equivalent fuel consumption conversion factor .

[0030] The state factor characterizing the state of charge of the battery system The fitting calculation formula is shown in formula (1): (1) (2) In formulas (1) and (2), the state factor Battery efficiency Diesel generator efficiency DC / DC converter efficiency Low calorific value of fuel in the system , Battery efficiency Low calorific value of fuel in the system For standardization.

[0031] Real-time value of battery state of charge Optimal state of charge during battery operation All values ​​are real-time collected / calculated.

[0032] Conversion factor This is used to perform a unified equivalent conversion between generator-side power loss and battery-side energy loss, and to obtain the battery's equivalent fuel consumption. This ensures that the loss values ​​output by the dissipation boundary function have the same energy dimension, providing a unified benchmark for subsequent calculations of loss-equivalent fuel consumption.

[0033] Step S30: Construct the objective function of the dissipation boundary of the diesel-electric hybrid power system.

[0034] Based on the SOC correlation parameters output in the previous step, as well as the engine / motor efficiency MAP (Manifold Absolute Pressure, Map, characteristic curve) diagram and fuel low calorific value calibration, the calculation of the equivalent fuel consumption of the motor and battery needs to be completed by equivalent conversion of their power loss. With the goal of "minimizing the sum of motor fuel consumption and battery equivalent fuel consumption", the objective function of the dissipation boundary of the diesel-electric hybrid system is constructed.

[0035] (3) (4) Formula (3) Known data: Real-time power dissipation of diesel generator Diesel generator efficiency Real-time power dissipation of the motor motor efficiency The system fuel has a low calorific value. .in , , For standardization, , Real-time data acquisition / calculation; Output data: Sum of actual fuel consumption of the diesel generator and electric motor. .

[0036] Formula (4) Known data: Real-time power dissipation of the battery Battery efficiency Low calorific value of fuel in the system Battery SOC state factor Battery equivalent fuel consumption conversion factor .in, , For standardization, To collect / calculate values ​​in real time, , Pre-calculated parameters; Output data: Equivalent fuel consumption of the battery. .

[0037] Objective function for constructing the dissipation boundary of a diesel-electric hybrid power system The calculation is shown in formula (5): (5) in, It is the objective function for studying the real-time dissipation boundary of the diesel-electric hybrid system, and it represents the minimum fuel consumption equivalent to the power loss of the diesel-electric hybrid system at different times. and These represent the fuel consumption of the diesel generator and the electric motor during operation, respectively. This is the equivalent fuel consumption of the power battery during operation. Among them, Direct correspondence The engine part, namely This part represents the actual fuel efficiency corresponding to the engine's output power. It is the equivalent fuel consumption of motor losses, corresponding to The motor part, namely This part converts the motor power loss into an equivalent fuel consumption rate, thus unifying the dimensions of motor loss and fuel consumption. It is the battery equivalent fuel consumption, which is directly equal to... This part is the equivalent fuel consumption rate after dynamic correction of battery charging and discharging power, reflecting the impact of battery energy changes on total fuel consumption.

[0038] for First, based on the real-time load requirements of the vehicle, the required engine output power is calculated. Then, using this power and engine speed, a pre-calibrated engine universal characteristic MAP is consulted to obtain the current fuel consumption rate. Finally, combining the fuel density and unit price, the fuel cost at this moment is calculated using the engine fuel consumption rate formula; the equivalent fuel consumption due to motor losses is also calculated. Similarly, by checking the motor's real-time output power and speed on a motor efficiency MAP chart, the current efficiency can be obtained, and then the motor's power loss can be calculated. Finally, using an equivalent fuel consumption formula similar to that for generators, the power loss is converted into equivalent fuel cost based on the engine's average power generation efficiency; battery equivalent fuel consumption... The calculation incorporates a state factor and converts the battery power change into an equivalent fuel consumption cost using the battery's equivalent fuel consumption formula, ultimately achieving a unified fuel consumption calculation method for each module.

[0039] This invention converts motor losses and battery charging and discharging into equivalent fuel consumption, constructs a joint objective function of "motor fuel consumption + battery equivalent fuel consumption", and achieves the minimization of fuel consumption through multi-component coordination.

[0040] Step S40: Set the optimization constraints for the above objective function.

[0041] Set the optimization constraints for the objective function above. These constraints include engineering parameters such as power / speed limits for each component, upper and lower limits of battery SOC, and battery capacity retention constraints. Output the set of constraints for the optimization calculation.

[0042] Next, with the goal of minimizing total fuel consumption, and considering constraints such as battery charge maintenance and power / speed limits of each component, optimization algorithms such as dynamic programming or model predictive control are used to solve for the optimal power allocation strategy of the engine and battery. The optimal strategy is then substituted into each component and the fuel consumption over the entire time period is accumulated to finally calculate the theoretical minimum fuel consumption of the diesel-electric hybrid system.

[0043] Step S50: Power distribution calculation.

[0044] Based on the optimization constraints of the above objective function, the objective function is solved using optimization algorithms such as dynamic programming and model predictive control to calculate the real-time output power sequence of the diesel generator, motor, and battery. The calculation process is as follows: First, the optimization objective and constraints are defined. The optimization objective is to minimize the objective... The core constraint is the battery's State of Charge (SOC), ensuring it remains within a normal range and preventing overcharging and over-discharging. Additionally, the output power and speed of the engine, motor, and battery must not exceed the hardware's limits. Secondly, optimization constraints are selected using dynamic programming. The state variable, battery SOC, reflects the system's energy storage level, while the control variable is the engine output power. The entire solution process uses power balance as a constraint. Based on this, the objective function is... As the fuel consumption cost at each step, starting from the last moment of the operating condition, the minimum cumulative cost under each SOC state is calculated backwards, ultimately yielding the optimal control sequence starting from the initial SOC. The derivation of the real-time output power sequence of the diesel generator, electric motor, and battery focuses on engine power. The output can be directly derived from the optimal control sequence obtained through dynamic programming, representing the engine output power that minimizes fuel consumption under the current load and SOC state; motor power. and battery power The power output sequence can be directly determined by the vehicle load demand and power balance constraints, respectively. After obtaining the power sequence through the optimization algorithm, it is substituted into the actual fuel consumption calculation formula to verify whether the minimum fuel consumption target is met. If it is not met (i.e., the condition is "N"), it is fed back to the power distribution calculation stage, and the control variables are adjusted and iterated again until the optimal real-time power output sequence is obtained.

[0045] Step S60: Calculate the actual fuel consumption power of the diesel-electric hybrid system.

[0046] Based on the real-time output power sequence of the diesel generator, electric motor and battery, as well as the fuel consumption rate interpolation and equivalent fuel consumption conversion formula of the engine fuel consumption rate MAP, the actual fuel consumption power of the diesel-electric hybrid system is calculated.

[0047] Formula (4) represents the total power balance of the system, used to verify the rationality of power allocation. Based on the above calculations, the formula for calculating the actual fuel consumption power of the diesel-electric hybrid system is shown in Formula (6): (6) in, For the real-time power dissipation of the diesel-electric hybrid power system, and These are the real-time power dissipation of the diesel generator and the electric motor, respectively. This represents the real-time power dissipation of the battery.

[0048] , and This was obtained based on the real-time output power sequence of the diesel generator, electric motor, and battery described above.

[0049] Step S70: Determine the optimality of fuel consumption.

[0050] The actual fuel consumption power of the diesel-electric hybrid system is compared with the historical best fuel consumption power threshold. If the actual fuel consumption power is greater than the historical best fuel consumption power threshold, the process returns to step S50 to recalculate the power distribution and recalculate the real-time output power sequence of the diesel generator, electric motor and battery. If the actual fuel consumption power is not greater than the historical best fuel consumption power threshold, step S80 is executed.

[0051] When the system detects that the system loss exceeds the threshold, it will be based on real-time... Determining the source of loss based on SOC: If the battery internal resistance loss is too high (corresponding to an extremely low or extremely high SOC), then adjust the generator's output power and voltage in conjunction with the equivalent coefficient. For example, when SOC ≤ 0.2, appropriately increase the generator's output power to improve the battery charging rate; when SOC ≥ 0.8, appropriately reduce the generator's output power to avoid overcharging the battery.

[0052] Step S80, power scheme output.

[0053] Based on the actual fuel consumption power of the diesel-electric hybrid system and the linear correlation between the power level of the diesel generator set and the dissipation boundary, the theoretical value of the minimum fuel consumption of the diesel-electric hybrid system is calculated, and the dissipation boundary of the diesel-electric hybrid system is obtained based on the theoretical value of the minimum fuel consumption of the diesel-electric hybrid system.

[0054] The dissipation boundary of a diesel-electric hybrid system is essentially the allowable range for component losses and power distribution to bring the system closer to the theoretical minimum fuel consumption. Specifically, it includes the following core elements: 1. Dissipated power boundary: This can be further divided into the upper limit of motor power loss, the upper limit of battery power loss, and the upper limit of total dissipated power. As the physical core of the dissipation boundary, the dissipated power boundary directly corresponds to the upper limit of system power loss.

[0055] 2. Equivalent fuel consumption rate boundary: The dissipated power is converted into an equivalent fuel consumption rate, which is consistent with the dimension of the engine fuel consumption rate, making it easier to control intuitively.

[0056] 3. Power Distribution Constraint Boundaries: From the perspective of power distribution, the output range of each component is limited to indirectly control power dissipation. Based on the power rating of the diesel generator set, the allowable output power of the engine under different operating conditions is defined to avoid operation in inefficient ranges; according to the SOC state and the upper limit of power dissipation, the charging and discharging power range of the battery is limited to prevent excessive charging and discharging from causing additional losses.

[0057] 4. Dynamically Adjusted Boundary: A dynamic threshold that adjusts in real time according to operating conditions and State of Charge (SOC) is the key difference from traditional fixed boundaries. This can be achieved through the battery SOC state factor. The upper limit of the battery equivalent fuel consumption rate is dynamically adjusted, and the boundary is automatically tightened or relaxed when the SOC deviates from the optimal value. In addition, the upper limit of the power dissipation and equivalent fuel consumption rate is updated in real time according to the changes in the vehicle load demand, so as to ensure that the fuel consumption is always close to the minimum under dynamic operating conditions.

[0058] The theoretical value of minimum fuel consumption is the result of the optimization objective calculation, representing the lowest fuel consumption level of the system under ideal power distribution; while the dissipation boundary is a constraint boundary further derived from the theoretical value of minimum fuel consumption, used to limit the allowable range of power loss in actual operation, thereby ensuring that the system can approach the theoretical optimal fuel consumption.

[0059] Based on the calculated sum of the dissipated power of the motor subsystem and the battery, and according to the equivalent conversion formula between total system fuel consumption and dissipated power, the reference speed of the system is determined through equivalent power loss and fuel consumption. The dissipation boundary of the diesel-electric hybrid power system is obtained by linearly linking the power level of the diesel generator set with the dissipation boundary.

[0060] Based on the real-time power of the diesel generator, a research curve for the real-time dissipation boundary of the diesel-electric hybrid power system is proposed to ensure that the system can reduce unnecessary fuel consumption while maintaining stable operation, thereby improving the system's economy and operational stability. Figure 3 This is a graph showing the relationship between the net output power of a motor and the internal losses of a system, provided in an embodiment of the present invention. Figure 3 The horizontal axis represents the net output power of the motor, in kW; the vertical axis represents the internal loss value corresponding to the current state of the system, in kW. Assuming the diesel generator's net output is 200kW, and the battery's SOC is 0.6, the internal loss of the diesel-electric hybrid system, calculated using the method above, is 17.5kW. Figure 3 The state at point A is shown. Initially, the functional relationship between the system's power source and internal losses was determined through motor operating data measurement and battery state function parameter fitting, providing a theoretical basis for determining the real-time dissipation boundary of the final target diesel-electric hybrid system.

[0061] Figure 4 This invention provides a diagram showing the relationship between internal system losses and fuel consumption. The horizontal axis represents the internal loss value corresponding to the current system state, in kW; the vertical axis represents the theoretical minimum fuel consumption corresponding to the internal system losses, in kg / h. Based on the calculated sum of the dissipated power of the motor subsystem and the battery, this invention provides a real-time calculation method for the dissipation boundary of a diesel-electric hybrid power system. According to the equivalent conversion formula between total system fuel consumption and dissipated power, the internal losses caused by the diesel generator set's power level are correlated with the fuel consumption of that portion. While determining the dissipation boundary, the minimum internal fuel consumption reference value during known system operating states is given. The specific correspondence is as follows: Figure 4 As shown in the figure, based on point B, the reference value for the system's internal fuel consumption at point A is 1.6 kg / h.

[0062] Figure 5 This invention provides a relationship between system internal losses and recommended speed, where the horizontal axis represents the internal loss value corresponding to the current system state, in kW; and the vertical axis represents the recommended motor speed value under the current loss condition, in rpm. Figure 5 As shown, this invention provides a real-time curve showing the relationship between the total loss of a diesel generator and its recommended speed. Simultaneously, it limits the upper limit of the speed based on actual system operating conditions to avoid unreasonable increases in speed. As shown at point C, when the internal system loss is known to be 17.5 kW, the corresponding recommended speed is 3700 r / min. Therefore, the method for controlling the diesel generator speed in this invention is as follows: when the output power of the diesel generator is determined, the corresponding speed is found in the curve as a reference value based on the preliminary determination of the total system loss, and then the diesel generator is further controlled.

[0063] Figure 6 This is the relationship between the system's recommended engine speed and the theoretical minimum fuel consumption in this embodiment of the invention, where the horizontal axis represents the system's recommended engine speed in rpm, and the vertical axis represents the calculated theoretical minimum fuel consumption in kg / h. Figure 6 Point D is Figure 5The relationship curve between diesel generator speed and theoretical minimum fuel consumption under the shown conditions was used to further determine the upper limit of the system speed based on the trend of the graph. At the same time, the fuel consumption at point D was found to be consistent with that at point C.

[0064] In summary, this invention provides a real-time calculation method for the dissipation boundary of a diesel-electric hybrid power system. The proposed method starts from the internal mechanism of the system, and the proposed method for studying the dissipation boundary function can provide the fuel consumption corresponding to the internal losses during the operation of the diesel-electric hybrid power system, and can also provide the real-time adjustment direction of the generator and battery state parameters based on the system operating state.

[0065] This invention fully considers the total internal losses, minimum fuel consumption, and reference speed of the diesel generator corresponding to the net output power of the diesel generator in actual operation of the diesel-electric hybrid system. By adjusting the conversion coefficient according to the generator power and the battery's SOC state, and combining real-time optimization calculation constraints, it ensures the rationality of energy distribution of each power source in the diesel-electric hybrid system and reduces the system's fuel consumption. This invention takes into account the relationship between the operating conditions of a series diesel-electric hybrid system and the fuel consumption caused by internal losses. While adjusting the battery state parameters in real time, it proposes a research curve for the real-time dissipation boundary of the diesel-electric hybrid system based on the real-time power of the diesel generator. This ensures that the system can reduce unnecessary fuel consumption while maintaining stable operation, thereby improving the system's economy and operational stability.

[0066] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0067] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. 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. Those skilled in the art can understand and implement this without creative effort.

[0068] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A real-time calculation method for the dissipation boundary of a diesel-electric hybrid power system, characterized in that, include: Data is collected on the power output of the diesel generator and electric motor, as well as the state of charge (SOC) of the battery in the diesel-electric hybrid system. The battery SOC state factor is then calculated based on the collected data. Battery equivalent fuel consumption conversion factor ; According to the above The above and the real-time power dissipation of the battery Calculate the equivalent fuel consumption of the battery. To minimize the sum of diesel generator fuel consumption and battery equivalent fuel consumption, an objective function for the dissipation boundary of the diesel-electric hybrid power system is constructed, and optimization constraints are set for the objective function. Based on the aforementioned optimization constraints, an optimization algorithm is used to solve the objective function, thereby obtaining the real-time output power sequence of the diesel generator, electric motor, and battery. The actual fuel consumption power of the diesel-electric hybrid power system is then calculated based on the real-time output power sequence of the diesel generator, electric motor, and battery. The actual fuel consumption power of the diesel-electric hybrid system is compared with the historical optimal fuel consumption power threshold. If the actual fuel consumption power is not greater than the historical optimal fuel consumption power threshold, the theoretical minimum fuel consumption value of the diesel-electric hybrid system is calculated based on the linear correlation between the actual fuel consumption power of the diesel-electric hybrid system, the power level of the diesel generator set, and the dissipation boundary. The dissipation boundary of the diesel-electric hybrid system is obtained based on the theoretical minimum fuel consumption value of the diesel-electric hybrid system.

2. The method according to claim 1, characterized in that, The aforementioned method collects the power of the diesel generator and electric motor, as well as the battery's state of charge (SOC) in the diesel-electric hybrid system, and calculates the battery SOC state factor based on the collected data. Battery equivalent fuel consumption conversion factor ,include: Collect power data of the diesel generator and electric motor, and battery SOC status data in the diesel-electric hybrid system. Then, based on the battery SOC value and a preset optimal SOC value... Calculate the battery SOC state factor Battery equivalent fuel consumption conversion factor ; The calculation formulas are shown in formulas (1) and (2): (1) (2) In formulas (1) and (2), For state factors, For battery efficiency, For diesel generator efficiency, For DC / DC converter efficiency, For the system fuel with low calorific value, , and For standardization.

3. The method according to claim 1, characterized in that, According to the above The above and the real-time power dissipation of the battery Calculate the equivalent fuel consumption of the battery. ,include: The sum of the actual fuel consumption of diesel generators and electric motors The calculation formula is shown in Figure (3), which represents the equivalent fuel consumption of the battery. The calculation formula is shown in Figure (4); (3) (4) In formula (3), This refers to the real-time power dissipation of the diesel generator. This refers to the real-time power dissipation of the electric motor. For motor efficiency, , For real-time acquisition / calculation of values; In formula (4), This refers to the real-time power dissipation of the battery. For real-time acquisition / calculation of values.

4. The method according to claim 3, characterized in that, The objective function for constructing the dissipation boundary of the diesel-electric hybrid power system aims to minimize the sum of the diesel generator's fuel consumption and the battery's equivalent fuel consumption. The optimization constraints for this objective function include: Objective function for constructing the dissipation boundary of a diesel-electric hybrid power system The calculation is shown in formula (5): (5) in, The minimum fuel consumption equivalent to the power loss of a diesel-electric hybrid system at different times; and These represent the fuel consumption of the diesel generator and the electric motor during operation, respectively. It is the equivalent fuel consumption of the power battery during operation. yes The actual fuel efficiency corresponding to the engine output power. ; yes Equivalent fuel consumption due to motor losses. , It is the equivalent fuel consumption rate after dynamic correction of battery charging and discharging power. equal ; The objective function is set with optimization constraints, which include: power / speed limits for each component, upper and lower limits of battery SOC, and battery capacity retention constraints.

5. The method according to claim 4, characterized in that, The aforementioned optimization algorithm solves the objective function based on the optimization constraints to obtain the real-time output power sequence of the diesel generator, electric motor, and battery. Based on this real-time output power sequence, the actual fuel consumption power of the diesel-electric hybrid system is calculated, including: Based on the optimization constraints of the objective function, ensuring that the battery SOC is in a normal state and that the output power and speed of the engine, motor, and battery do not exceed the hardware's tolerance limits, the objective function is solved using an optimization algorithm. Dynamic programming is employed to control the selection of engine output power. The entire solution process uses power balance as a constraint, and the objective function is... As the fuel consumption cost at each step, starting from the last moment of the operating condition, the minimum cumulative cost under each SOC state is calculated in reverse to finally obtain the optimal control sequence starting from the initial SOC. The optimal control sequence is substituted into the actual fuel consumption calculation formula to verify whether it meets the minimum fuel consumption target. If it does not meet the target, it is fed back to the power distribution calculation stage, and the control variables are adjusted and iterated again until the optimal real-time output power sequence of the diesel generator, motor and battery is obtained.

6. The method according to claim 5, characterized in that, The calculation of the actual fuel consumption power of the diesel-electric hybrid system based on the real-time output power sequence of the diesel generator, electric motor, and battery includes: The real-time power dissipation of the diesel generator is obtained based on the real-time output power sequence of the diesel generator, electric motor, and battery. Real-time power dissipation of the motor and the real-time power dissipation of the battery Calculate the actual fuel consumption power of the diesel-electric hybrid system. The calculation formula is shown in formula (6): (6)。 7. The method according to claim 6, characterized in that, The process involves comparing the actual fuel consumption power of the diesel-electric hybrid system with a historical optimal fuel consumption power threshold. If the actual fuel consumption power is not greater than the historical optimal fuel consumption power threshold, the theoretical minimum fuel consumption value of the diesel-electric hybrid system is calculated based on the linear correlation between the actual fuel consumption power of the diesel-electric hybrid system, the power level of the diesel generator set, and the dissipation boundary. The dissipation boundary of the diesel-electric hybrid system is then obtained based on this theoretical minimum fuel consumption value, including: The actual fuel consumption power of the diesel-electric hybrid system is compared with the historical optimal fuel consumption power threshold. If the actual fuel consumption power is greater than the historical optimal fuel consumption power threshold, the power allocation is recalculated, and the real-time output power sequence of the diesel generator, electric motor and battery is recalculated. If the actual fuel consumption power is not greater than the historical best fuel consumption power threshold, based on the actual fuel consumption power of the diesel-electric hybrid system and the linear correlation between the diesel generator set power level and the dissipation boundary, the theoretical minimum fuel consumption value of the diesel-electric hybrid system is calculated. Based on this theoretical minimum fuel consumption value, the dissipation boundary of the diesel-electric hybrid system is obtained, which includes:

1. Dissipated power boundary: Specifically, it can be divided into the upper limit of motor power loss, the upper limit of battery power loss, and the upper limit of total dissipated power.

2. Equivalent fuel consumption rate boundary: Converting dissipated power into equivalent fuel consumption rate, unifying the dimensions with engine fuel consumption rate; 3. Power distribution constraint boundary: From the perspective of power distribution, the output range of each component is limited to indirectly control the power dissipation; the charging and discharging power range of the battery is limited according to the SOC state and the upper limit of the power dissipation.

4. Dynamic correction boundary: A dynamic threshold that is adjusted in real time according to changes in operating conditions and SOC.

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