A Power Flow Calculation Method for Series Hybrid Drive Tracked Vehicles

Abstract

This invention discloses a power flow calculation method for series hybrid drive tracked vehicles, belonging to the field of hybrid vehicle control technology. This invention is the first to specifically model the configuration of a series tracked vehicle consisting of an engine, generator, high-voltage bus, and dual independent motors, capable of characterizing its unique electrical coupling and power distribution relationships. Starting from physical formulas, it constructs straight-line driving and steering condition models, integrating key factors unique to tracked vehicles such as slip loss, internal friction, and steering power cycle, making power demand prediction more realistic. The model architecture is modular and the parameters are open, allowing for vehicle-level power flow analysis and energy management strategy development, as well as for matching design and performance evaluation of transmission system components. This provides a foundational tool for subsequent design and verification of energy management algorithms with multiple objectives, including improving fuel economy, driving range, and system thermal safety.

Description

Technical Field

[0001] This invention belongs to the field of hybrid vehicle control technology, specifically relating to a power flow calculation method for series hybrid drive tracked vehicles. Background Technology

[0002] Series hybrid power systems, due to their advantages such as decoupling the engine from the drive wheels and the ability to always operate in the high-efficiency range, have become an important technological direction for special vehicles, especially tracked vehicles. In this configuration, the engine drives a generator to produce electricity, which, along with the electricity from the power battery, is collected on a high-voltage bus to drive independent drive motors on both sides, either together or individually, thereby propelling the tracks. The core of achieving efficient energy management lies in constructing a power flow calculation method that can accurately describe the internal relationships of energy flow, conversion, and distribution from the energy source to the final actuator.

[0003] Currently, power flow modeling and optimization techniques have been applied in multiple fields. For example, in the power grid field, patent CN111211583A proposes a hybrid power grid control method based on a fully nonlinear safety-constrained optimal power flow calculation model; in the aviation field, patent CN120278041A establishes a power flow calculation model for a turbine power generation system and a battery, and uses this as a basis for energy management optimization; in the electric vehicle field, patent CN112561169A designs a hybrid model predictive control strategy by constructing a model that includes a transmission system, a motor, and a battery.

[0004] However, directly applying existing technologies to series hybrid tracked vehicles has the following significant shortcomings: ① Lack of configuration specificity: Existing models are mainly designed for fixed power grids, parallel hybrid architectures, or aviation platforms, lacking dedicated modeling for the power flow path unique to series tracked vehicles, namely "engine-generator-high voltage bus-independent drive motors on both sides." It is difficult to accurately characterize the dynamic coupling relationship between generator power, high voltage bus voltage, battery compensation power, and the torque and speed of the drive motors on both sides under this configuration.

[0005] ② Neglecting the unique power demand of tracked vehicles under straight-line driving conditions: Existing models based on wheeled vehicles typically only include basic components such as rolling resistance, air resistance, and gradient resistance in their driving resistance models. However, for tracked vehicles, especially when driving straight on complex terrain, their power demand models require more refined modeling. The straight-line power flow of tracked vehicles not only includes the aforementioned basic resistances but also needs to consider unique factors such as slippage losses caused by the interaction between the tracks and the ground during center-turning conditions, and internal meshing and friction losses within the track system. Furthermore, targeted dynamic modeling for center-turning conditions is required. These factors have a significant impact on the accurate prediction of the vehicle's straight-line power demand; ignoring them will lead to the failure of power distribution strategies under complex conditions.

[0006] To meet the development and verification requirements of relevant standards for military hybrid electric drive vehicles (GJB 7114 General Specification for Military Hybrid Electric Drive Vehicles) and armored vehicle transmission systems (GJB 1910 General Specification for Armored Vehicle Transmission Systems), a power flow calculation model specifically for series hybrid tracked vehicles is urgently needed. This model needs to characterize its unique power transmission path and loss characteristics from a dynamic mechanism perspective, thereby laying a reliable foundation for the optimized design and performance evaluation of the vehicle's energy management strategy. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a power flow calculation method for series hybrid drive tracked vehicles, aiming to achieve the following objectives:

[0008] ① Targeted modeling: Accurately characterize the unique electrification power transmission path of series hybrid tracked vehicles, which consists of "engine-generator set, power battery, high-voltage bus, and dual independent drive motors", and clearly define the power balance and state coupling relationship of each link.

[0009] ② Mechanistic integration: Realize power flow calculation for multiple working conditions such as straight driving, center turning, and climbing based on the dynamic model of tracked vehicles.

[0010] ③ Support for collaborative optimization: Provide core computing tools for subsequent energy management with the collaborative optimization of multiple objectives such as improving fuel economy and passability.

[0011] A power flow calculation method for series hybrid drive tracked vehicles includes: Step 1: Construct a dynamics submodule for tracked vehicles under straight-line driving conditions and a dynamics submodule for center-steering conditions; Step 2: Build the following in the simulation platform: The engine-generator submodule is used to represent the mapping relationship between engine torque, speed and generator output power; Based on the traction force output by the dynamics submodule under the straight-driving condition and the dynamics submodule under the center-turning condition of the tracked vehicle, a drive motor submodule is constructed. A battery submodule that calculates the changes in terminal voltage and charging / discharging current; An observation submodule used to observe the power flow data of various component nodes of the vehicle and the vehicle status; Step 3: In the system modeling and simulation platform, complete the transmission of data signals of each sub-module, establish the input and output coupling relationship of each sub-module and the interrelationship of the sub-modules, and complete the model integration; Step 4: Assign values ​​to the required vehicle parameters in the system modeling and simulation platform according to the specific design specifications of the target vehicle; Step 5: Set the required vehicle driving conditions, run the integrated model, and observe the sub-model to obtain the power flow data of each component node and the vehicle state change curve.

[0012] Preferably, in step 3, during model integration, the power flow transmission path is ensured to conform to the following high-voltage bus power balance equation: (1) in, , These represent the input power of the vehicle's left and right drive motors, respectively. , These represent the generator output power and the power battery output power, respectively. This represents the power of the vehicle's auxiliary systems.

[0013] Preferably, in step 3, model integration is performed using MWorks, MATLAB, or Simulink.

[0014] Preferably, the dynamics submodule for the tracked vehicle in straight-line driving condition is constructed as follows: (2) in, This refers to the track traction force actively generated by the vehicle to overcome resistance and propel the vehicle forward; Indicates the overall vehicle weight. Represents gravitational acceleration; This represents the component of gravity parallel to the slope. Represents the rolling resistance coefficient. Represents the overall resistance of the track system. The component of the vehicle's weight perpendicular to the slope / the normal force exerted on the ground; Represents air resistance, The air drag coefficient, The vehicle's frontal area. This represents the vehicle's speed relative to the air. Represents the slope correction factor. This represents the current gradient of the vehicle's trajectory. This represents acceleration resistance, which is the force required to overcome the translational inertia of the vehicle. Indicates the radius of the driving wheel. This represents the moment of inertia of the engine flywheel and its coaxial rotating components. This represents the moment of inertia of the wheels and track drive wheels; This refers to the gear ratio of the motor reduction gearbox. For different gear ratios of a vehicle. For the side transmission ratio, The total transmission efficiency; Representing the rotational mass inertial drag, which is the force equivalent to the driving wheel that overcomes the rotational inertia of all rotating components, this term introduces a mass increase factor acting on the translational mass of the entire vehicle. Calculate the equivalent track traction force Achieve approximate equivalence: (3) in, Indicates the mass increase coefficient. This refers to air density.

[0015] Preferably, the dynamics submodule for center steering is constructed as follows: (4) in, This indicates the driving torque of a single active wheel under center steering conditions, expressed in N·m. This indicates the radius of the drive wheel, in meters (m). This indicates the distance between the center lines of the left and right tracks, in meters (m). This represents the transmission efficiency between the drive wheel and the track, and is dimensionless. The torque of inertia required to produce the center steering angle acceleration of a vehicle is expressed in N·m. The moment of inertia of a vehicle about its vertical central axis, expressed in units of 1000 kilometres per minute. ; This represents the angular acceleration of the vehicle about its vertical central axis, measured in rad / s². This represents the overall drag torque during center steering, expressed in N·m.

[0016] Furthermore, the steady-state center of gravity steering track traction force is calculated as follows: (5) in, This represents the required traction force on one side of the track under steady-state center turning conditions, expressed in N. This represents the overall drag torque at the center of rotation, expressed in N·m. This indicates the distance between the center lines of the left and right tracks, in meters (m). This represents the center steering drag coefficient, which is dimensionless. This indicates the total weight of the vehicle, expressed in N (units). This represents the ground contact length of a single track, in meters; the constant 8 is an empirical coefficient and is dimensionless.

[0017] The steady-state center steering torque of the single-sided active wheel is: (6) in, This represents the driving torque of a single active wheel under steady-state center steering conditions, expressed in N·m. This represents the required traction force on one side of the track under steady-state center turning conditions, expressed in N. This indicates the radius of the drive wheel, in meters (m). It represents the transmission efficiency between the drive wheel and the track, and is dimensionless.

[0018] Preferably, the engine-generator submodule is constructed as follows: The engine is directly connected to the generator, meaning the engine output speed... Input speed to generator Engine output torque Input torque to the generator ,Right now: (7) (8) For series hybrid tracked vehicles, the actual vehicle engine adopts a constant speed control strategy, namely: (9) in, Represents a constant; Since the engine and generator are directly connected, we have: (10) Coupled modeling of engine and generator efficiency maps is used, with the output being the generator's power output. Generator input power satisfy: (11) in For engine output torque, This refers to the engine output speed. For engine efficiency, Indicates engine efficiency With engine output torque Engine output speed There is a function mapping relationship; engine efficiency under different engine operating conditions can be obtained by querying the corresponding map. Numerical value; Define the maximum power loading rate of the component. This physical quantity is used to reflect the power supply capability of a component, namely: (12) in, For component type, when The time indicates the engine. The time indicates the power battery; Indicates components The maximum power loading rate, in kW / s; Indicates components exist The output power or compensation power at any given moment, in kW; Time is expressed in units of 10 ... ; This indicates the rate of change of component power over time, expressed in kW / s.

[0019] Therefore, the available output power of the engine is: (13) in, express The available output power of the engine at any given time, in kW; This indicates the engine's peak output power, measured in kW. This indicates the engine's preloaded power or initial output power, measured in kW. This indicates the engine's maximum power loading rate, expressed in kW / s. The simulation time is expressed in seconds. This indicates that the smaller value within the parentheses is used to ensure that the engine output power does not exceed the peak power limit.

[0020] The generator's available output power is: (14) in, express The generator's available output power at any given time, in kW; This represents generator efficiency and is dimensionless. This represents the generator controller efficiency, which is dimensionless. express The engine's available output power at any given time, measured in kW.

[0021] The available compensated power of the battery is: (15) in, express The available compensation power of the battery at any given time, in kW; This indicates the peak output power of the battery, in kW. This indicates the initial available compensation power of the battery, in kW; This indicates the battery's maximum power loading rate, expressed in kW / s. The simulation time is expressed in seconds. This indicates that the smaller value within the parentheses is used to ensure that the battery compensation power does not exceed the battery's peak output capacity.

[0022] The overall vehicle power requirement is: (16) This indicates the total electrical power requirement of the vehicle under current operating conditions, expressed in kW. This indicates the input electrical power of the left-side drive motor, in kW; This indicates the input electrical power of the drive motor on the right, in kW. This indicates the power of the vehicle's auxiliary systems, measured in kW.

[0023] The total power supplied by the vehicle is: (17) in, express The maximum electrical power that the entire vehicle can supply at any given time, in kW; express The available output power of the generator at any given time, in kW; express The available compensation power of the battery at any given time, in kW.

[0024] The power supply capacity constraint is: (18) in, express The maximum electrical power that the entire vehicle can supply at any given time, in kW; This inequality represents the total electrical power requirement of the vehicle under current operating conditions, expressed in kW. It also indicates that the electrical power provided by the engine-generator set and the power battery should not be less than the total electrical power requirement of the vehicle under current operating conditions.

[0025] To meet the transient power requirements of the vehicle, the following power control strategy is designed: (19) (20) in, The simulation time corresponds to the duration of the rapid acceleration condition. , These represent the power of the left and right drive motors, respectively. This represents the maximum power that the entire vehicle can provide. The power demand is represented by the vehicle under different operating conditions. Inequality (19) represents the power supply capacity of the whole vehicle to meet the power demand of the current vehicle operating conditions. This represents the maximum power output considering the engine-generator power chain. This represents the maximum output power considering the battery power loading rate. Represents the engine's maximum power loading rate. Represents the battery's maximum power loading rate. This represents the peak power of the generator nameplate. This represents the peak power indicated on the battery nameplate. Represents the engine's preload power; For generator efficiency, For generator controller efficiency; Based on the above power control logic and the power flow transmission relationship of the whole vehicle, the engine output power is obtained. And further solve for the engine output torque. Generator input torque Generator output power and generator current : (twenty one) (twenty two) (twenty three) in, This represents the high-voltage bus voltage of a series hybrid tracked vehicle.

[0026] Preferably, the drive motor submodule is constructed as follows: The input to the drive motor submodule is the drive motor speed. With demand pull The vehicle speed calculated based on the dynamics submodule Determine the drive motor speed: (twenty four) in, This refers to the gear ratio of the motor reduction gearbox. For different gear ratios of a vehicle. The side transmission ratio; Drive motor torque The calculation is as follows: (25) in, This represents the traction force required on the side of a single drive motor. Represents the radius of the drive wheel. To improve the efficiency of the drive motor reduction gearbox. For the efficiency of the coupling mechanism, For side transmission efficiency; To improve the efficiency of tracked vehicle mobility systems; Based on the dynamics submodules corresponding to different working conditions, the output torque of a single drive motor is transmitted to the track via the motion system to generate track traction force, thereby meeting the traction force requirement of one side of the track under that working condition. : Straight driving condition (26) Center turning condition (27) Based on the speed of the drive motor With torque Find the output power of the drive motor. for: (28) Then the drive motor current can be obtained. for: (29) in To improve the efficiency of the drive motor, To improve the efficiency of the drive motor controller, This is the voltage at the drive motor terminals, and this voltage value is the same as the high-voltage bus voltage. (30).

[0027] Preferably, the battery submodule is constructed by including: In a series connection architecture where the battery is directly connected to the bus, the battery current... It depends on the battery output power. Terminal voltage / Open circuit voltage Calculations are performed; subsequently, the change in battery state of charge (SOC) is obtained by integrating the current, and the battery output power is updated accordingly. ; Battery output power With current It can be obtained from the following formula: (31) (32) in, Indicates the battery output power. , These represent the input power of the left and right drive motors, respectively. Represents the generator output power. Represents the battery open-circuit voltage; Based on the current calculation results, the SOC solution is completed using the Thevenin equivalent circuit module: (33) in, Represents the initial state of charge (SOC) of the battery. This represents the maximum capacity of the battery.

[0028] Preferably, the observation submodule measures: engine output power, generator output power, drive motor output power, drive motor input power, battery compensation power, engine input power, and battery state of charge. .

[0029] The present invention has the following beneficial effects: (1) Highly targeted: For the first time, a model was specifically designed for the series tracked vehicle configuration of "engine-generator-high voltage bus-dual independent motors", which can depict its unique electrical coupling and power distribution relationship.

[0030] (2) Clear mechanism: The straight driving and turning working condition models are constructed based on physical formulas, integrating key factors such as slip loss, internal friction and turning power cycle unique to tracked vehicles, making the power demand prediction closer to reality.

[0031] (3) Good practicality: The model architecture is modular and the parameters are open, which can be used for vehicle-level power flow analysis and energy management strategy development, as well as for matching design and performance evaluation of transmission system components.

[0032] (4) Support optimization: Provide basic tools for the subsequent design and verification of energy management algorithms with multiple objectives such as improving fuel economy, driving range and system thermal safety. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the input and output of the power flow calculation model of the present invention; Figure 2 This is a schematic diagram of the power flow of the tracked vehicle power system based on a series architecture according to the present invention; Figure 3 This refers to the simulation time configuration in Embodiment 1 of the present invention; Figure 4 The output power of the engine at 85 km / h in this embodiment of the invention is shown in kW. Figure 5 The output power of the generator at 85 km / h in this embodiment of the invention is shown in kW. Figure 6 The output power of the drive motor at 85 km / h in this embodiment of the invention is shown in kW. Figure 7 This refers to the simulation time configuration for Example 2 in this embodiment of the invention; Figure 8The output power of the climbing engine at 10km / h in this embodiment of the invention is shown in kW. Figure 9 The output power of the 10km / h climbing generator in this embodiment of the invention is shown in kW. Figure 10 The output power of the 10km / h climbing drive motor in this embodiment of the invention is shown in kW. Figure 11 This refers to the simulation time configuration in Example 3 of this invention. Figure 12 The output power of the center steering engine in 5s (kW) is the result of the engine output power in this embodiment of the invention. Figure 13 The output power of the center steering generator in 5 seconds is shown in kW in this embodiment of the invention. Figure 14 The output power of the center steering drive motor in 5s (kW) is the result of this invention embodiment. Figure 15 This refers to the simulation time configuration in Example 4 of this invention. Figure 16 The output power of the rapidly accelerating engine in this embodiment of the invention is shown in kW. Figure 17 The output power of the rapidly accelerating generator in this embodiment of the invention is shown in kW. Figure 18 The output power of the rapid acceleration drive motor in this embodiment of the invention is shown in kW. Figure 19 The result of rapid acceleration battery compensation power (kW) in this embodiment of the invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] To achieve the above objectives, this invention proposes a power flow calculation method for series hybrid powertrain tracked vehicles. The model systematically integrates two main calculation components: the power flow of the series powertrain and the power demand of the tracked travel mechanism. A schematic diagram of the system input and output of the power flow calculation model is shown below. Figure 1 As shown: (1) Overview of power flow calculation model based on series architecture like Figure 2 As shown, this model is applicable to a series configuration of "diesel engine / gas turbine—generator—high-voltage bus—power battery—dual-sided drive motor—dual-sided reducer—dual-sided drive wheel". In this configuration, the high-voltage bus is defined as the power hub of the system, used for collecting and distributing electrical energy.

[0036] The power of the high-voltage bus must satisfy the following instantaneous balance equation: (34) in, , These represent the input power of the left and right drive motors, respectively. , These represent the generator output power and the power battery output power, respectively. This represents the power of the vehicle's auxiliary systems.

[0037] (2) Modeling of each sub-module of the power flow calculation model 1) Straight-line driving dynamics submodule The straight-driving dynamics submodule considers the vehicle climbing situation (the slope can be parameterized), and its calculation formula is as follows: (35) in, This represents the track traction force actively generated by the vehicle to overcome resistance and propel the vehicle forward. ; Indicates the total vehicle weight (kg). Expressing gravitational acceleration (m / s²) 2 ); The component of gravity in the direction parallel to the slope. ; Represents the rolling resistance coefficient. Represents the overall resistance of the track system , The component of the vehicle's weight perpendicular to the slope / normal force on the ground ; Represents air resistance , The air drag coefficient, For the vehicle's frontal area , Represents the vehicle's speed relative to the air. , Represents the slope correction factor. Represents the current vehicle's driving gradient. ; Represents acceleration resistance This refers to the force required to overcome the translational inertia of the vehicle.

[0038] Indicates the radius of the driving wheel. This represents the moment of inertia of the engine flywheel and its coaxial rotating components. This represents the moment of inertia of the wheels and track drive wheels (as well as follower wheels, carrier rollers, etc.); This refers to the gear ratio of the motor reduction gearbox. For different gear ratios of a vehicle. For the side transmission ratio, This represents the total transmission efficiency.

[0039] Represents the inertial drag of rotating mass This refers to overcoming the force equivalent to the drive wheels caused by the rotational inertia of all rotating components, including the engine, generator, transmission system, and tracked running gear. This can be achieved by introducing a mass increase factor acting on the translational mass of the entire vehicle. Calculate the equivalent track traction force Achieve approximate equivalence: (36) in, Indicates the mass increase coefficient. air density .

[0040] In summary, the input-output mapping relationship of the dynamics submodule for straight-line driving is shown in Table 1: Table 1 Input-output mapping relationship of the dynamics submodule for straight driving condition.

[0041] 2) Center Steering Dynamics Submodule During the center turn of a tracked vehicle, the core of its dynamics module is the rotational torque balance equation around the vertical axis of the vehicle, which can be found in formulas (4), (5) and (6).

[0042] It should be noted that the center steering dynamics submodule is a highly simplified lumped parameter model, which does not take into account the changes in track tension, vehicle pitch and roll motion, the precise distribution of track-ground interaction forces, or the detailed dynamic characteristics of the transmission and suspension systems.

[0043] This submodule is applicable to the analysis of the vehicle's center steering process.

[0044] The input-output mapping relationship of the center steering dynamics submodule is shown in Table 2 below: Table 2 Input-output mapping relationship of the dynamics submodule for center steering condition

[0045] 3) Engine-generator submodule The engine-generator submodule is used to simulate the power conversion characteristics of the prime mover's power generation unit. Its core is to establish the mapping relationship between engine torque / speed and generator output power. As the power source of the entire vehicle, the engine adopts a constant speed, variable torque control strategy, and its output torque must meet the dynamic requirements of the entire vehicle under different operating conditions.

[0046] Coupled modeling of engine and generator efficiency maps is used, with the output being the generator's power output. Generator input power satisfy: (37) in For engine output torque, This refers to the engine output speed. Engine efficiency, representing engine efficiency. With engine output torque Engine output speed There is a function mapping relationship, and the engine efficiency under different engine operating conditions can be obtained by querying the corresponding map. Numerical value.

[0047] Based on the above theoretical analysis, for the series hybrid drive tracked vehicle configuration with battery directly connected to the bus, in order to meet the power requirements of the vehicle under changing working conditions such as acceleration, it is necessary to take into account the overall power supply capacity of the vehicle and apply a certain power preload to the battery.

[0048] This invention defines the maximum power loading rate of the component. This is the peak output power of the component. Regarding time The derivative of , which is a physical quantity used to reflect the power supply capability of a component, namely: (38) in, The name of the component (including the engine and the power battery). Indicates the peak output power of the component Based on the above description, to meet the transient power requirements of the vehicle, the following power control strategy is designed; whereby... Represents simulation time The duration is consistent with that of rapid acceleration: (39) (40) in, , These represent the power of the left and right drive motors, respectively. This represents the maximum power that the entire vehicle can provide. The power demand is based on different operating conditions of the vehicle. Inequality (14) represents the power supply capacity of the whole vehicle to meet the power demand of the current vehicle operating conditions. This represents the maximum power output considering the engine-generator power chain. This represents the maximum output power considering the battery power loading rate. Represents the engine's maximum power loading rate. Represents the battery's maximum power loading rate. This represents the peak power of the generator nameplate. This represents the peak power indicated on the battery nameplate. This represents the engine's preload power. For generator efficiency, This refers to the generator controller efficiency. The above power units... Power loading rate unit .

[0049] Based on the above power control logic (39) and (40) and the power flow transmission relationship of the whole vehicle, the engine output power can be obtained. And further solve for the engine output torque. Generator input torque Generator output power and generator current : (41) (42) (43) in, High voltage bus voltage of series hybrid tracked vehicles .

[0050] Based on the above control logic and calculation formulas, an engine-generator coupling module can be established, which obtains the engine speed. With engine output power To achieve the output torque of the engine Generator input speed Generator input torque Generator power output With the power generation current Solve the problem. The input-output mapping relationship of the engine-generator submodule is shown in Table 3.

[0051] Table 3 Input-output mapping relationship table for engine-generator submodule

[0052] 4) Drive motor submodule The drive motors on both sides of the series hybrid drive tracked vehicle follow an independent driving mode. To simplify the description, the following uses a single drive motor submodule as an example to illustrate its modeling process. The other drive motor submodule is the same.

[0053] The input to the drive motor submodule is the drive motor speed. With demand pull The vehicle speed is calculated based on the dynamics submodule. Determine the drive motor speed: (44) in, This refers to the gear ratio of the motor reduction gearbox. For different gear ratios of a vehicle. This is the side transmission ratio.

[0054] For the 0-32km / h, 5-second rapid acceleration straight driving condition considered by this model, the vehicle speed With acceleration Satisfies the uniform acceleration relationship: (45) in, Represents acceleration time Drive motor torque The calculation is as follows: (46) in, Represents the traction demand on the side of a single drive motor. , Represents the radius of the drive wheel , To improve the efficiency of the drive motor reduction gearbox. For the efficiency of the coupling mechanism, For side transmission efficiency. For the tracked vehicle's motion system to be efficient, satisfying empirical formulas, the vehicle speed... Units are : (47) Based on the dynamic sub-modules corresponding to the different working conditions mentioned above, the output torque of a single drive motor is transmitted to the track via the motion system to generate track traction force, thereby meeting the traction force requirement of one side of the track under that working condition. : (48) (49) Based on the speed of the drive motor With torque Find the output power of the drive motor. for: (50) Then the drive motor current can be obtained. for: (51) in To improve the efficiency of the drive motor, To improve the efficiency of the drive motor controller, This is the voltage at the drive motor terminals, and this voltage value is the same as the high-voltage bus voltage. (52) In summary, the input-output mapping relationship of the drive motor submodule is shown in Table 4 below: Table 4 Input / Output Mapping Relationship of Drive Motor Submodule

[0055] 5) Battery submodule The core of the battery submodule is calculating the changes in terminal voltage and charging / discharging current. In a series architecture where the battery is directly connected to the bus, the battery current... It depends on the battery output power. Terminal voltage / Open circuit voltage Calculations are then performed. Furthermore, by integrating the current, the change in the battery's state of charge (SOC) can be obtained, and the battery output power can be updated accordingly. .

[0056] Battery output power With current It can be obtained from the following formula: (53) (54) in, Indicates battery output power , , These represent the input power of the left and right drive motors, respectively. , Represents generator output power , Represents the battery open-circuit voltage This value is related to the battery's current SOC and can be obtained through a 1D Lookup Table.

[0057] Based on the current calculation results, the SOC solution is completed using the Thevenin equivalent circuit module: (55) in Represents the initial state of charge (SOC) of the battery. Represents the maximum battery capacity .

[0058] In summary, the input-output mapping relationship of the battery submodule is shown in Table 5 below: Table 5 Input / Output Mapping Relationship of Battery Submodule

[0059] 6) Observation Submodule The physical quantities observed by the observation submodule are shown in the table below, including power observations and non-power observations: Table 6 Observations of the Power Flow Observation Submodule

[0060] (3) Model parameters Based on the above modeling, all parameters used in the model and their meanings are as follows: Table 7. Parameters used in the power flow calculation model and their corresponding meanings

[0061] (4) The specific implementation of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0062] The power flow calculation model described in this invention can be implemented using system modeling and simulation platforms such as MWorks and MATLAB / Simulink.

[0063] The implementation steps are as follows: Step 1: Driving Dynamics Modeling Based on the above dynamic calculation formulas for straight driving and center turning conditions of tracked vehicles, corresponding dynamic sub-modules are constructed respectively.

[0064] Step 2: Submodule Modeling In the simulation platform, engine-generator, drive motor, battery and observation sub-modules are constructed respectively; Step 3: Integration of power flow calculation models In system modeling and simulation platforms such as MWorks and MATLAB / Simulink, the Goto / From module is used to complete the transmission of data signals between various sub-modules, establish the input and output coupling relationship of each sub-module and the mutual relationship between sub-modules, and ensure that the power flow transmission path is consistent with the power balance equation.

[0065] Step 4: Parameter Configuration Based on the specific design specifications of the target vehicle, assign values ​​to each parameter in Table 7.

[0066] Step 5: Observation and Simulation Establish an observation submodule and set corresponding simulation conditions (such as constant speed driving at 85km / h, climbing a 35° slope at 10km / h, center turning, and rapid acceleration straight driving from 0-32km / h). By running the model, the power flow data of each component node and the vehicle state change curve can be obtained.

[0067] The present invention will be described below using four embodiments: Table 8. Description of the Embodiments

[0068] Example 1: Constant speed straight driving at 85km / h Taking a series hybrid tracked vehicle as an example, the slope angle in Table 9 is set to 0°, the vehicle speed is configured to be 85 km / h, and the simulation time is 300 s. The simulation outputs the calculation results, and the observation submodule is used to observe the results such as engine output power, generator output power, and drive motor output power. Figure 3 , 4 As shown in Figures 5 and 6.

[0069] The observations at the end of the simulation are summarized below: Table 9 Calculation Results of Example 1

[0070] Example 2: Climbing condition at 10km / h on a 35° slope Taking a series hybrid tracked vehicle as an example, the slope angle in Table 10 is set to 35°, the vehicle speed in the model is configured to be 10 km / h, and the simulation time is 30 seconds. The simulation outputs the calculation results, and the observation submodule is used to observe the results such as engine output power, generator output power, and drive motor output power. Figure 7 , 8 As shown in 9 and 10.

[0071] Table 10 Calculation Results of Example 2

[0072] Example 3: 5s center steering condition Taking a series hybrid tracked vehicle as an example, the slope angle in Table 11 is set to 0°, and the center turning time in the model is configured to be 5 seconds, i.e., the simulation time is set to 5 seconds. The calculation results are output during the simulation, and the observation submodule is used to observe the results such as engine output power, generator output power, and drive motor output power. Figure 11 , 12 As shown in 13 and 14.

[0073] Table 11, Calculation Results of Example 3

[0074] Example 4: 0-32km / h, 5s rapid acceleration straight driving condition Taking a series hybrid tracked vehicle as an example, with the slope angle set to 0° in Table 12, and considering that rapid acceleration is a dynamic condition, the following configuration is required in the model: (56) in, The value 32 represents the vehicle speed at the moment of termination of the rapid acceleration condition, in m / s; the value 32 represents the final vehicle speed, in km / h; the constant 3.6 represents the conversion factor between km / h and m / s. (57) in, This represents the linear acceleration of a vehicle, measured in m / s². The vehicle speed at the moment the rapid acceleration condition ends is expressed in m / s. This indicates the initial velocity under rapid acceleration conditions, in m / s. This indicates the duration of rapid acceleration, measured in seconds (s).

[0075] Therefore, the relationship between vehicle speed and time is: (58) in, express Vehicle speed at any given time, in m / s; This indicates the initial speed of the vehicle, in m / s. This represents the linear acceleration of a vehicle, measured in m / s². This represents the simulation time, expressed in seconds (s).

[0076] Therefore, the vehicle speed is set to 0 km / h, and the acceleration is... The simulation time is 5 seconds. The simulation outputs calculation results and utilizes the observation submodule to observe results such as engine output power, generator output power, drive motor output power, and battery compensation power. Figure 15 , 16 As shown in 17, 18 and 19.

[0077] Table 12 Calculation results of Example 4

[0078] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A power flow calculation method for series hybrid drive tracked vehicles, characterized in that, include: Step 1: Construct a dynamics submodule for tracked vehicles under straight-line driving conditions and a dynamics submodule for center-steering conditions; Step 2: Build the following in the simulation platform: An engine-generator submodule used to represent the mapping relationship between engine torque, speed and generator output power; Based on the traction force output by the dynamics submodule under the straight-driving condition and the dynamics submodule under the center-turning condition of the tracked vehicle, a drive motor submodule is constructed. A battery submodule that calculates the changes in terminal voltage and charging / discharging current; An observation submodule used to observe the power flow data of various component nodes of the vehicle and the vehicle status; Step 3: In the system modeling and simulation platform, complete the transmission of data signals of each sub-module, establish the input and output coupling relationship of each sub-module and the interrelationship of the sub-modules, and complete the model integration; Step 4: Assign values ​​to the required vehicle parameters in the system modeling and simulation platform according to the specific design specifications of the target vehicle; Step 5: Set the required vehicle driving conditions, run the integrated model, and observe the sub-model to obtain the power flow data of each component node and the vehicle state change curve.

2. The power flow calculation method for series hybrid power driven tracked vehicles as described in claim 1, characterized in that, In step 3, during model integration, ensure that the power flow transmission path conforms to the following high-voltage bus power balance equation: （1） in, , These represent the input power of the vehicle's left and right drive motors, respectively. , These represent the generator output power and the power battery output power, respectively. This represents the power of the vehicle's auxiliary systems.

3. The power flow calculation method for series hybrid power driven tracked vehicles as described in claim 1 or 2, characterized in that, In step 3, model integration is performed using MWorks, MATLAB, or Simulink.

4. The power flow calculation method for series hybrid power driven tracked vehicles as described in claim 1 or 2, characterized in that, The dynamics submodule for the tracked vehicle under straight-line driving conditions is constructed as follows: （2） in: （3） （4） （5） （6） in, The required track traction force for the entire vehicle under straight-line driving conditions is expressed in N. The total vehicle weight is expressed in kg. This is the acceleration due to gravity, in units of 1. ; The slope angle is expressed in rad. The rolling resistance coefficient is dimensionless. air density, unit: ; The air drag coefficient is dimensionless. The windward area is expressed in units of... ; Vehicle speed, unit: ; It is a dimensionless mass increase factor used to convert the equivalent inertia of rotating components into the translational mass of the vehicle.

5. The power flow calculation method for series hybrid drive tracked vehicles as described in claim 4, characterized in that, The dynamics submodule for tracked vehicles under center turning conditions is constructed according to the following torque balance relationship: （7） in, This indicates the distance between the center lines of the left and right tracks that touch down, in units of 1. ; The moment of inertia of a vehicle about its vertical central axis, expressed in units of 1000 m / s. ; This represents the angular acceleration of the vehicle about its vertical central axis, measured in units of . ; This indicates the tangential traction force on the right track contact point, expressed in N. This indicates the tangential traction force on the left track contact point, expressed in N. This represents the combined steering resistance torque generated by the interaction between the tracks and the ground during center turn, expressed in N·m. The center steering resistance torque is expressed as: （8） in, This represents the center steering drag coefficient, which is dimensionless. This indicates the total weight of the vehicle, expressed in N (units). represents the single-sided track ground contact length, in meters; constant 8 is a dimensionless coefficient obtained based on the equivalent distribution of track ground contact pressure. Since the tracks on both sides satisfy equal-size and opposite-direction driving when the tracked vehicle turns at the center, let: （9） in, This indicates the required traction force of a single track under center turning conditions, in N; the negative sign indicates that the traction forces of the left and right tracks are in opposite directions. This yields the required traction force for a single track under center-steering conditions: （10） The single-sided drive wheel torque under center steering conditions is: （11） in, This indicates the driving torque of a single active wheel under center steering conditions, expressed in N·m. This indicates the radius of the drive wheel, in meters (m). This represents the transmission efficiency between the drive wheel and the track, and is dimensionless. This represents the moment of inertia at the center of rotation, expressed in N·m. This represents the center steering resistance torque, expressed in N·m. When the steady-state center turns, it satisfies ,therefore: （12） in, This represents the required traction force on one side of the track under steady-state center turning conditions, expressed in N. The corresponding steady-state center steering torque for the single-sided active wheel is: （13） in, This represents the driving torque of a single active wheel under steady-state center steering conditions, expressed in N·m.

6. The power flow calculation method for series hybrid drive tracked vehicles as described in claim 5, characterized in that, The engine-generator submodule is constructed as follows: The engine is directly connected to the generator, meaning the engine output speed... Input speed to generator Engine output torque Input torque to the generator ,Right now: （14） （15） For series hybrid tracked vehicles, the actual vehicle engine adopts a constant speed control strategy, namely: （16） in, Represents a constant; Since the engine and generator are directly connected, we have: （17） Coupled modeling of engine and generator efficiency maps is used, with the output being the generator's power output. Generator input power satisfy: （18） in For engine output torque, This refers to the engine output speed. For engine efficiency, parentheses Indicates engine efficiency With engine output torque Engine output speed There is a function mapping relationship; engine efficiency under different engine operating conditions can be obtained by querying the corresponding map. Numerical value; Define the maximum power loading rate of the component. This is the derivative of the component's peak output power with respect to time. This physical quantity reflects the component's power supply capability, i.e.: （19） in, For component names, Indicates the peak output power of the component; To meet the transient power requirements of the vehicle, the following power control strategy is designed: （20） （21） in, The simulation time corresponds to the duration of the rapid acceleration condition. , These represent the power of the left and right drive motors, respectively. This represents the maximum power that the entire vehicle can provide. The power demand is based on different operating conditions of the vehicle. Inequality (14) represents the power supply capacity of the whole vehicle to meet the power demand of the current vehicle operating conditions. This represents the maximum power output considering the engine-generator power chain. This represents the maximum output power considering the battery power loading rate. Represents the engine's maximum power loading rate. Represents the battery's maximum power loading rate. This represents the peak power of the generator nameplate. This represents the peak power indicated on the battery nameplate. Represents the engine's preload power; For generator efficiency, For generator controller efficiency; Based on the above power control logic and the power flow transmission relationship of the whole vehicle, the engine output power is obtained. And further solve for the engine output torque. Generator input torque Generator output power and generator current : （22） （23） （24） in, This represents the high-voltage bus voltage of a series hybrid tracked vehicle.

7. The power flow calculation method for series hybrid power driven tracked vehicles as described in claim 6, characterized in that, The drive motor submodule is constructed as follows: The input to the drive motor submodule is the drive motor speed. Traction required by a single track The vehicle speed calculated based on the dynamics submodule Determine the drive motor speed: （25） in, This refers to the gear ratio of the motor reduction gearbox. For different gear ratios of a vehicle. The side transmission ratio; Drive motor torque The calculation is as follows: （26） in, This represents the traction force required by a single track on one side of a single drive motor. Represents the radius of the drive wheel. To improve the efficiency of the drive motor reduction gearbox. For the efficiency of the coupling mechanism, For side transmission efficiency; To improve the efficiency of tracked vehicle mobility systems; Based on the dynamics submodules corresponding to different working conditions, the output torque of a single drive motor is transmitted to the tracks via the motion system to generate track traction force, thereby meeting the required traction force under that working condition. : （27） in, This represents the required traction force on one side of the track for a single drive motor, expressed in N. This indicates the required track traction force for the entire vehicle under straight-driving conditions, expressed in N. This indicates the required traction force of a single track under center turning conditions, expressed in N. Under straight-driving conditions, the drive motors on the left and right sides of the vehicle output symmetrically, so the traction force required by a single track is half of the traction force required by the entire vehicle for straight-driving. Under center-steering conditions, the traction force required by a single track is directly calculated by the center-steering dynamics submodule. The angular velocity of the drive motor output shaft is: （28） in, This indicates the angular velocity of the drive motor's output shaft, measured in rad / s. This indicates the vehicle's speed, expressed in m / s. This indicates the radius of the drive wheel, in meters (m). This represents the gear ratio of the drive motor reduction gearbox; it is dimensionless. This indicates the current gear ratio of the vehicle and is dimensionless. This represents the side transmission ratio and is dimensionless. Expressed in terms of rotational speed: （29） in, It is a dimensionless number; This indicates the output shaft speed of the drive motor, in r / min. This indicates the angular velocity of the output shaft of the drive motor, in rad / s. The output torque of the drive motor is: （30） in, This indicates the output torque of the drive motor, in N·m. This indicates the required traction force for one side of the track, expressed in N. This indicates the radius of the drive wheel, in meters (m). This represents the gear ratio of the drive motor reduction gearbox; it is dimensionless. This indicates the current gear ratio of the vehicle and is dimensionless. This represents the side transmission ratio and is dimensionless. This represents the efficiency of the drive motor reduction gearbox, and is dimensionless. This represents the efficiency of the coupling mechanism and is dimensionless. This represents the side transmission efficiency, which is dimensionless. This represents the efficiency of a tracked vehicle's motion system; it is dimensionless. The output power of the drive motor is: （31） in, This indicates the output mechanical power of the drive motor, measured in kW. This indicates the output torque of the drive motor, in N·m. This represents the angular velocity of the drive motor's output shaft, in rad / s; the constant 1000 is used to convert W to kW. The input power of the drive motor is: （32） in, This indicates the input electrical power of the drive motor, measured in kW. This indicates the output mechanical power of the drive motor, measured in kW. This represents the efficiency of the drive motor and is dimensionless. This represents the efficiency of the drive motor controller; it is dimensionless. The drive motor current is: （33） in, Indicates the input current of the drive motor; Indicates the input electrical power of the drive motor; This indicates the voltage of the high-voltage bus.

8. The power flow calculation method for series hybrid drive tracked vehicles as described in claim 7, characterized in that, The battery sub-module is constructed as follows: In a series connection architecture where the battery is directly connected to the bus, the battery current... It depends on the battery output power. Terminal voltage / Open circuit voltage Calculations are performed; subsequently, the change in battery state of charge (SOC) is obtained by integrating the current, and the battery output power is updated accordingly. ; Battery output power With current It can be obtained from the following formula: （34） （35） in, Indicates the battery output power. , These represent the input power of the left and right drive motors, respectively. Represents the generator output power. Represents the battery open-circuit voltage; Based on the current calculation results, the SOC solution is completed using the Thevenin equivalent circuit module: （36） in, Represents the initial state of charge (SOC) of the battery. This represents the maximum capacity of the battery.

9. The power flow calculation method for series hybrid drive tracked vehicles as described in claim 7, characterized in that, The observation submodule measures the following: engine output power, generator output power, drive motor output power, drive motor input power, battery compensation power, engine input power, and battery state of charge. .

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