In-wheel motor electric vehicle electric drive assembly simulation method

Abstract

The application discloses a kind of based on multi-time scale's wheel hub motor electric automobile electric drive assembly simulation method, mainly is: first, by establishing wheel hub motor electric automobile electric drive assembly model in Simulink (a kind of visual simulation tool), form the high-precision simulation method capable of transient characteristic description to the driving module of electric automobile in driving process, it mainly includes permanent magnet synchronous wheel hub motor empirical formula model and equivalent circuit battery model, simulation step in this module needs to select smaller value, to ensure simulation accuracy;Then, the output parameter of external vehicle dynamics model is processed by interpolation by time scale transformation method, and the output parameter of wheel hub motor electric automobile electric drive assembly model is integrated;Finally, form a multi-time scale wheel hub motor electric automobile electric drive assembly simulation method with smaller internal step and larger external step, the simulation efficiency in the scene with higher precision simulation requirement can be greatly improved by the method, with great application value.

Description

Technical Field

[0001] This patent relates to the field of vehicle dynamics simulation technology, specifically to a simulation method for improving the multi-model calculation efficiency of electric vehicle electric drive assemblies. Background Technology

[0002] Vehicle simulation is an important method in the design, development and testing of vehicles. Its accuracy and fine granularity play an important role in the stability and safety of vehicles. At the same time, it is also one of the main means to reduce the cost of vehicle testing. A complete vehicle simulation platform should include the following parts: scene module, driver module, vehicle dynamics module, parameter output module, etc. The in-wheel motor electric drive assembly simulation method based on multi-time scale proposed in this invention improves the electric drive assembly part in the vehicle dynamics module.

[0003] Currently, commonly used vehicle simulation software primarily simulates gasoline-powered vehicles. The drive system typically employs lookup table-based engine models, eliminating time inconsistency issues. However, electric vehicle simulations mostly utilize lookup table-based motor models, resulting in lower simulation accuracy and difficulty in describing motor simulation failures. For models capable of describing motor transient characteristics, the simulation time is long and the efficiency is low. Currently, there is no method that can simultaneously balance simulation accuracy and efficiency. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to improve simulation efficiency while accurately describing the transient characteristics of motors.

[0005] To address the above problems, this invention provides a simulation method for an electric drive assembly of an electric vehicle with a hub motor, comprising the following steps:

[0006] S1: Construct a model of the electric drive assembly of the in-wheel motor electric vehicle and an external vehicle dynamics simulation model in the simulation platform;

[0007] S2: The parameter requirements of the external vehicle dynamics simulation model are interpolated and then input into the empirical formula model of the hub motor electric drive assembly through the time scale transformation interpolation module to obtain the output parameters of the electric drive assembly.

[0008] S3: The output parameters of the electric drive assembly are integrated and then input into the external vehicle dynamics simulation model through the time scale transformation integration module;

[0009] S4: Determine whether the preset simulation time has been reached. If yes, output the simulation result; otherwise, proceed to step S2.

[0010] In step S2, the time scale transformation interpolation module unifies the step size in the external vehicle dynamics simulation model to be consistent with the step size in the hub motor electric drive assembly model in terms of time scale.

[0011] In step S3, the time scale transformation and integration module unifies the step size in the hub motor electric drive assembly model to be consistent with the step size in the external vehicle dynamics simulation model in terms of time scale.

[0012] Furthermore, in step S1, the electric drive assembly model of the in-wheel motor electric vehicle is established using the empirical formula differential equation of the permanent magnet synchronous hub motor and the battery equivalent circuit differential equation.

[0013] Furthermore, step S2 includes:

[0014] S21: Input the parameter requirements of the external vehicle dynamics simulation model into the time scale transformation interpolation module;

[0015] S22: Compare the time of the clock module in the time scale transformation interpolation module with the simulation step size of the hub motor electric vehicle electric drive assembly model. When the time is an integer multiple of the simulation step size of the external vehicle dynamics simulation model, input the parameters of the next moment into the electric drive assembly model; otherwise, input the parameters of the current moment into the hub motor electric vehicle electric drive assembly model.

[0016] S23: Obtain the output parameters of the in-wheel motor electric drive assembly model for electric vehicles.

[0017] 4. Further, step S3 includes:

[0018] S31: Input the output parameters of the in-wheel motor electric vehicle electric drive assembly model into the time scale transformation interpolation module;

[0019] S32: The integrated parameters of the electric drive assembly output parameters are obtained by using a zero-order hold, and the sampling time is taken as the simulation step size of the external vehicle dynamics simulation model;

[0020] S33: Input the integrated electric drive assembly output parameters into the external vehicle dynamics simulation model.

[0021] Furthermore, the input parameters of the hub motor electric vehicle electric drive assembly model in step S1 are interpolated demand parameters, including speed demand and torque demand, and the output parameters include the speed, torque, voltage, current and efficiency of the hub motor.

[0022] Furthermore, step S33 includes:

[0023] S331: The parameter command after interpolation, after being subject to constraints, transmits the PWM control signal to the inverter module;

[0024] S332: Transmit the parameters output by the inverter module to the empirical formula model of the permanent magnet synchronous hub motor to obtain the control sequence of the electric drive assembly;

[0025] S333: Obtain the output parameters of the in-wheel motor electric drive assembly model of electric vehicles through the motor control sequence.

[0026] Furthermore, in step S331, the constraints include: speed control, current control, combined with battery power limitation and transient characteristics.

[0027] Furthermore, after step S1, the method further includes: calibrating the parameters of the hub motor electric vehicle electric drive assembly model based on the electric drive assembly parameters used in the actual vehicle.

[0028] Furthermore, the calibrated parameters include: the dq-axis inductance, armature resistance, and moment of inertia of the four hub motors, and the rated current, rated voltage, and rated power of the power battery in the electric drive assembly model.

[0029] The present invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, can implement the above-described simulation method for the electric drive assembly of a hub motor electric vehicle, and calibrate the parameters of the electric drive assembly model of the hub motor electric vehicle according to the parameters of the electric drive assembly used in actual vehicles.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] In complex scenarios, the electric drive system of a vehicle exhibits strong nonlinear relationships. Traditional lookup table models are insufficient for simulation requirements, while empirical formula models require excessively long simulation times. This patent establishes a multi-timescale electric drive simulation method, creating a multi-timescale electric drive assembly model. Through interaction with external vehicle dynamics simulation software, it improves the simulation efficiency of the drive system and provides sufficiently accurate electric drive parameters for in-wheel motor electric vehicles. Simulation experiments have confirmed that it can simultaneously guarantee both simulation efficiency and accuracy. Attached Figure Description

[0032] Figure 1 Flowchart summarizing the simulation of the electric drive assembly model for an electric vehicle with a hub motor;

[0033] Figure 2 Schematic diagram of a hub motor electric drive assembly for electric vehicles;

[0034] Figure 3 Detailed flowchart of simulation of the electric drive assembly model for electric vehicles with hub motors;

[0035] Figure 4Schematic diagram of the time scale transformation module of the simulation model. Detailed Implementation

[0036] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] According to the embodiment of the present invention, the simulation method for the electric drive assembly of a hub motor electric vehicle establishes a multi-time-scale electric drive assembly model. By interacting with external vehicle dynamics simulation software, the simulation efficiency of the drive part is improved, and sufficiently accurate electric drive parameters for hub motor electric vehicles are provided.

[0039] Firstly, a hub motor electric drive assembly model for an electric vehicle is provided, which can be used to calibrate the simulation system based on actual vehicle parameters. The model includes:

[0040] The simulation includes parameter input / output interfaces, a PWM signal control model, a four-wheel permanent magnet synchronous motor model, and a battery model. In the electric drive assembly section, a simulation step size of 10 is used to meet the control signal requirements. -5 S-10 -7 The value s can be adjusted according to actual needs. Signal generation is achieved through PWM pulse modulation. Simulink has corresponding modules for this. The relationship between the parameter commands and the input parameters is as follows: after the parameter commands are transmitted, they are passed to the PWM module via PI modules, etc., for pulse modulation.

[0041] During the parameter calibration process, the parameters of the electric drive assembly used in the actual vehicle are combined to calibrate the dq-axis inductance, armature resistance, and moment of inertia of the four hub motors in the hub motor electric vehicle electric drive assembly model. The rated current, rated voltage, and rated power of the power battery in the electric drive assembly model are also calibrated. Simulation calculations are performed on the calibrated model to obtain the corresponding original electric drive assembly speed and torque results.

[0042] Secondly, a simulation method for the electric drive assembly of an electric vehicle based on a multi-timescale hub motor is provided to improve simulation efficiency. The method includes:

[0043] Based on the simulation step size of the in-wheel motor electric drive assembly simulation model and the simulation step size of the external vehicle dynamics simulation software, a multi-timescale selection module is established using clock signals, zero-order hold circuits, and selection modules. This module interpolates the parameter commands input to the in-wheel motor electric drive assembly simulation model and integrates the original result parameters output by the in-wheel motor electric drive assembly model, ensuring a larger simulation step size (10) in the external vehicle dynamics simulation software. -2 S-10 -3 s), the simulation step size of the electric drive assembly is relatively small (10 -5 S-10 -7 Simulation calculations are performed synchronously under the condition of s).

[0044] Specifically, this invention provides a simulation method for the electric drive assembly of an electric vehicle based on a multi-timescale hub motor, which includes two aspects:

[0045] Firstly, referring to Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, a model of the electric drive assembly of an electric vehicle with a hub motor is established.

[0046] First, based on the speed and torque requirements of each wheel after interpolation, the required signals for the motor are parameter-controlled, including speed control, current control, and PWM control. The control strategies can include traditional id=0 control, MTPA control (maximum torque-to-current ratio control), MTPV control (maximum torque-to-voltage ratio control), field weakening control, etc. The control parameters are transmitted as gate signals to the IGBT (Insulated Gate Bipolar Transistor) of the inverter module, and the DC signal from the power battery is converted into the AC signal required by the empirical formula model of the permanent magnet synchronous hub motor through the inverter.

[0047] Secondly, in the power battery section, by establishing an equivalent circuit model and a SOC (state of charge) estimation model, the driving voltage and driving current can be accurately provided for the empirical formula model of the permanent magnet synchronous hub motor. When the speed and torque change suddenly, the voltage and current required by the motor will change and be delayed. The power battery model provided by this invention can effectively describe the transient characteristics of the driving parameters caused by changes in external parameters, providing a possible method for the accurate simulation of the electric drive assembly.

[0048] Secondly, referring to Figure 2 and Figure 3As shown, time-scale transformation is performed using a clock module, a zero-order hold, and a selection module. This interpolates the parameters input to the in-wheel motor electric vehicle electric drive assembly model and integrates the output parameters of the model. This ensures that the in-wheel motor electric vehicle electric drive assembly model and the external vehicle dynamics simulation software run synchronously, thereby reducing simulation time.

[0049] In the time-scale transformation-interpolation module, the external dynamics model input is a step size of 10. -2 S-10 -3 The parameter requirements of 's' are determined by comparing the clock module's time with the simulation step size of the electric drive assembly model to obtain the interpolation conditions. When the time is 10... -2 S-10 -3 When the value is an integer multiple of s, input the parameters for the next time step into the electric drive assembly model; otherwise, input the parameters for the current time step into the electric drive assembly model.

[0050] In the time-scale transformation-integration module, the original output of the in-wheel motor electric vehicle electric drive assembly model is in step size 10. -5 S-10 -7 Parameters such as rotational speed and torque, if directly output to an external dynamic model, will cause an error. Therefore, a zero-order hold is used here, with a sampling time of 10. -2 S-10 -3 s (i.e., the simulation step size of the external vehicle dynamics model) is used to obtain integrated parameters, which are then output to the external vehicle dynamics simulation software.

[0051] exist Figure 4This invention provides an example of a practical simulation test process, which includes an external vehicle dynamics model input, an interpolation module, a unit conversion module, a speed-current PI control module, a pulse modulation module, a battery module, an IGBT module, a permanent magnet synchronous motor empirical formula model, a measurement module, a coordinate transformation module, an integration module, and an output module. Among them, the interpolation module and the integration module are the time scale transformation parts of this invention, and are the core modules for improving simulation efficiency and reducing simulation time. In the interpolation module, the interpolation time is determined by comparing the clock signal with an integer multiple of a large step size, and the dynamic requirement parameters at integer multiple times are input into the motor model within a small step time range through a zero-order hold. When the simulation of the motor model ends at the current moment, its simulation result is a set of data with a small step size, which includes the simulation results of the motor speed, torque, voltage, and current. Under a large simulation step size, it contains multiple sets of data. Here, the integration method is adopted, and the simulation results at integer times are retained through a zero-order hold to improve the simulation efficiency of the external vehicle dynamics simulation software. The simulation results show that the traditional electric vehicle simulation method takes 2394.012152 seconds to complete the simulation, while the multi-timescale in-wheel motor electric vehicle simulation method takes 182.623892 seconds. Compared with the traditional electric vehicle simulation method, the multi-timescale electric vehicle simulation method proposed in this invention has improved efficiency by more than 10 times, and the results are quite significant.

[0052] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0053] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0054] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0055] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0056] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A simulation method for an electric drive assembly of an electric vehicle with a hub motor, characterized in that, Includes the following steps: S1: Construct a model of the electric drive assembly of the in-wheel motor electric vehicle and an external vehicle dynamics simulation model in the simulation platform; S2: The parameter requirements of the external vehicle dynamics simulation model are interpolated and then input into the empirical formula model of the hub motor electric drive assembly through the time scale transformation interpolation module to obtain the output parameters of the electric drive assembly. S3: The output parameters of the electric drive assembly are integrated and then input into the external vehicle dynamics simulation model through the time scale transformation integration module; S4: Determine whether the preset simulation time has been reached. If yes, output the simulation result; otherwise, proceed to step S2. In step S2, the time scale transformation interpolation module unifies the step size in the external vehicle dynamics simulation model to be consistent with the step size in the hub motor electric drive assembly model in terms of time scale. In step S3, the time scale transformation and integration module unifies the step size in the hub motor electric drive assembly model to be consistent with the step size in the external vehicle dynamics simulation model in terms of time scale. Step S3 includes: S31: Input the output parameters of the in-wheel motor electric vehicle electric drive assembly model into the time scale transformation interpolation module; S32: The integrated parameters of the electric drive assembly output parameters are obtained by using a zero-order hold, and the sampling time is taken as the simulation step size of the external vehicle dynamics simulation model; S33: Input the integrated electric drive assembly output parameters into the external vehicle dynamics simulation model; Step S33 includes: S331: The parameter command after interpolation, after being subject to constraints, transmits the PWM control signal to the inverter module; S332: Transmit the parameters output by the inverter module to the empirical formula model of the permanent magnet synchronous hub motor to obtain the control sequence of the electric drive assembly; S333: Obtain the output parameters of the in-wheel motor electric drive assembly model of electric vehicles through the motor control sequence.

2. The simulation method for the electric drive assembly of an electric vehicle with a hub motor as described in claim 1, characterized in that, In step S1, the electric drive assembly model of the electric vehicle using the empirical formula differential equation of the permanent magnet synchronous hub motor and the battery equivalent circuit differential equation is established.

3. The simulation method for the electric drive assembly of an electric vehicle with a hub motor as described in claim 1, characterized in that, Step S2 includes: S21: Input the parameter requirements of the external vehicle dynamics simulation model into the time scale transformation interpolation module; S22: Compare the time of the clock module in the time scale transformation interpolation module with the simulation step size of the hub motor electric vehicle electric drive assembly model. When the time is an integer multiple of the simulation step size of the external vehicle dynamics simulation model, input the parameters of the next moment into the electric drive assembly model; otherwise, input the parameters of the current moment into the hub motor electric vehicle electric drive assembly model. S23: Obtain the output parameters of the in-wheel motor electric drive assembly model for electric vehicles.

4. The simulation method for the electric drive assembly of an electric vehicle with a hub motor as described in claim 1, characterized in that, In step S4, the time scale transformation integration module achieves time scale unification between the output parameters of the electric drive assembly and the required parameters of the external vehicle dynamics simulation model through a combination of clock signal, zero-order hold, and selection module, wherein the selection module is a built-in Simulink module.

5. The simulation method for the electric drive assembly of an electric vehicle with a hub motor as described in claim 1, characterized in that, The input parameters of the hub motor electric drive assembly model for electric vehicles in step S1 are interpolated demand parameters, including speed demand and torque demand. The output parameters include the speed, torque, voltage, current, and efficiency of the hub motor.

6. The simulation method for the electric drive assembly of an electric vehicle with a hub motor as described in claim 1, characterized in that, In step S331, the constraints include: speed control, current control, combined with battery power limitation and transient characteristics.

7. The simulation method flow for the in-wheel motor electric drive assembly of an electric vehicle as described in claim 1, characterized in that, Step S1 is followed by: calibrating the parameters of the hub motor electric vehicle electric drive assembly model according to the electric drive assembly parameters used in the actual vehicle.

8. The simulation method flow for the in-wheel motor electric drive assembly of an electric vehicle as described in claim 7, characterized in that, The calibrated parameters include: the dq axis inductance, armature resistance, and moment of inertia of the four hub motors, and the rated current, rated voltage, and rated power of the power battery in the electric drive assembly model.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program can implement the simulation method for the electric drive assembly of a hub motor electric vehicle as described in any one of claims 1-8, and calibrate the parameters of the electric drive assembly model of the hub motor electric vehicle according to the parameters of the electric drive assembly used in actual vehicles.

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