Electric passenger vehicle driving system and inherent characteristic verification method thereof

Abstract

The invention discloses an electric passenger vehicle driving system and an inherent characteristic verification method thereof. The system comprises a driving motor, a two-stage speed reducer gear transmission assembly, an axle and wheels which are connected in sequence. Wherein a dual-mass flywheel is connected between the driving motor and the two-stage speed reducer gear transmission assembly, and the dual-mass flywheel comprises a driving disc, an elastic damping device and a driven disc which are connected in sequence; wherein the driving disc is fixedly connected with an output shaft of the driving motor and is used for receiving electromagnetic torque generated by the driving motor; the elastic damping device comprises a torsional rigidity element and a damping element which are arranged between the driving disc and the driven disc, and the driven disc is fixedly connected with an input shaft of the transmission assembly and used for outputting torque buffered by the dual-mass flywheel to the transmission assembly. Through the electric drive system structure with the dual-mass flywheel, the problem that torsional vibration of a traditional drive system cannot be controlled is solved, meanwhile, the inherent frequency and all-order vibration modes of the whole system are changed, and adjustment of the inherent characteristics of the system is achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of electric drive systems, and in particular relates to an electric passenger vehicle drive system and a method for verifying its inherent characteristics. Background Art

[0002] With the rapid development of the new energy vehicle industry and the increasing market share year by year, pure electric passenger vehicles not only attract consumers to buy and use them with their strong power and good economy, but also attract automobile manufacturers to develop and manufacture them with their simple power transmission system structure and strong integration.

[0003] However, a growing number of consumers report that pure electric passenger vehicles can cause discomfort for drivers and passengers, even leading to dizziness and nausea. This is because pure electric vehicles lack vibration damping devices in their drivetrains. Instead, the drive motor, as the power source, directly drives the wheels after passing through a speed reducer, reducing the ride comfort for drivers and passengers.

[0004] As a crucial component of the powertrain of pure electric vehicles, the electric drive system typically includes a drive motor, a motor controller, and a secondary reducer. The output of the electric drive system drives the wheels through the reducer, differential, and half-axles. During this process, many nonlinear factors can cause torsional vibration in the electric drive system, such as the electromagnetic coupling characteristics of the motor, the time-varying stiffness of the gear meshing in the secondary reducer, and the backlash. However, the electric drive systems currently used in pure electric vehicles often directly drive the wheels with the motor, or directly connect the motor output shaft to the secondary reducer input shaft to drive the wheels. Both systems lack a device to reduce torsional vibration, which not only makes it impossible to control the torsional vibration of the vehicle but also makes it impossible to adjust the inherent characteristics of the electric drive system. Summary of the Invention

[0005] The present application provides a self-vibration-damping electric drive system configuration with a flexible transmission device, which aims to solve the problems of uncontrollable torsional vibration and unadjustable inherent characteristics of existing electric passenger vehicle drive systems.

[0006] To solve the above technical problems, on the one hand, the present application provides an electric passenger vehicle drive system, characterized in that the system includes:

[0007] A drive motor, a secondary speed reducer gear transmission assembly, an axle and wheels connected in sequence;

[0008] Wherein, a dual-mass flywheel is connected between the drive motor and the secondary reducer gear transmission assembly, and the dual-mass flywheel includes a driving disc, an elastic damping device and a driven disc connected in sequence;

[0009] Among them, the active disk is fixedly connected to the output shaft of the drive motor, and is used to receive the electromagnetic torque generated by the drive motor; the elastic damping device includes a torsional stiffness element and a damping element arranged between the active disk and the driven disk, and the driven disk is fixedly connected to the input shaft of the transmission assembly, and is used to output the torque buffered by the dual mass flywheel to the transmission assembly.

[0010] On the other hand, the present application also provides a method for verifying the inherent characteristics of an electric passenger vehicle drive system, the method comprising:

[0011] Establish dynamic models of various components based on the electric passenger vehicle drive system;

[0012] The electric passenger vehicle drive system includes a drive motor, a secondary reducer gear transmission assembly, a wheel axle, and a wheel connected in sequence; a dual-mass flywheel is connected between the drive motor and the transmission assembly, and the dual-mass flywheel includes a driving disc, an elastic damping device, and a driven disc connected in sequence;

[0013] After coupling the dynamic models of the components of the electric passenger vehicle drive system to complete basic parameter transfer, a time domain dynamic characteristics simulation is performed;

[0014] A torsional vibration model of the electric passenger vehicle drive system is established, and the natural frequencies of each vibration mode of the electric passenger vehicle drive system are solved.

[0015] Compared with the existing technology, by adding a dual-mass flywheel as a flexible transmission device to the traditional electric vehicle power system, the self-damping electric drive system structure effectively solves the problem of uncontrollable torsional vibration of the traditional pure electric vehicle power transmission system. At the same time, due to the introduction of new rotational inertia and torsional stiffness parameters, the natural frequency of the entire system and the vibration modes of each order of the system are changed, thereby realizing the adjustment of the inherent characteristics of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 A schematic structural diagram of a drive system for an electric passenger vehicle provided in an embodiment of the present application;

[0018] Figure 2 for Figure 1 A schematic diagram of the steps of a method for verifying inherent characteristics of a drive system of an electric passenger vehicle according to the illustrated embodiment;

[0019] Figure 3 for Figure 1 A schematic diagram of the dynamic characteristics of the drive motor and its control system in the embodiment shown;

[0020] Figure 4 for Figure 1 A schematic diagram of the dynamic characteristics of the elastic force of the dual-mass flywheel in the embodiment shown;

[0021] Figure 5 for Figure 1 A schematic diagram of the dynamic characteristics of the gear transmission assembly of the secondary speed reducer in the embodiment shown;

[0022] Figure 6 for Figure 1 A schematic diagram of optimization results of a drive system for an electric passenger vehicle in time domain characteristics provided by the illustrated embodiment;

[0023] Figure 7 This is a schematic diagram of the torsional vibration system of a traditional pure electric vehicle powertrain;

[0024] Figure 8 for Figure 1 A schematic diagram of a torsional vibration system of an electric passenger vehicle drive system according to the illustrated embodiment;

[0025] Figure 9 for Figure 1 A schematic diagram of optimization results of a drive system for an electric passenger vehicle in the frequency domain according to the illustrated embodiment is shown. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application; it should be understood that the specific implementation methods described here are only used to illustrate and explain the present invention and are not used to limit this application. In this application, unless otherwise specified, the directional words used, such as "up, down, left, and right", generally refer to the up, down, left, and right indicated with reference to the drawings. "Inside" and "outside" refer to the inside and outside relative to the outline of the component itself.

[0027] Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0028] See Figure 1The present application proposes an embodiment of an electric passenger vehicle drive system. In this embodiment, the system includes a drive motor 1, a secondary reducer gear transmission assembly 3, an axle and a wheel connected in sequence; wherein a dual-mass flywheel 2 is connected between the drive motor and the secondary reducer gear transmission assembly, and the dual-mass flywheel 2 includes a driving disc, an elastic damping device and a driven disc connected in sequence; wherein the driving disc is fixedly connected to the output shaft of the drive motor for receiving the electromagnetic torque generated by the drive motor; the elastic damping device includes a torsional stiffness element and a damping element arranged between the driving disc and the driven disc, and the driven disc is fixedly connected to the input shaft of the transmission assembly for outputting the torque buffered by the dual-mass flywheel to the transmission assembly.

[0029] Specifically, if Figure 1 As shown, the drive system utilizes a serial arrangement consisting of a drive motor 1, a dual-mass flywheel 2, a secondary reducer gear assembly 3, an axle, and wheels. These components are rigidly connected via mechanical shafts, forming a complete power transmission chain. The drive motor 1 can be a permanent magnet synchronous motor, with its output shaft secured to the active disc of the dual-mass flywheel 2, such as by a key or flange connection. The dual-mass flywheel 2 is positioned between the motor and the reducer, with the active disc receiving motor torque and the driven disc connected to the reducer input shaft. The secondary reducer gear assembly 3 comprises two gear pairs, such as spur or helical gears, to increase output torque through a reduction ratio. The dual-mass flywheel 2 operates as follows: when the electromagnetic torque output by the drive motor 1 fluctuates, the active disc first causes the elastic element to deform. The driven disc then responds with a delayed response due to its rotational inertia, resulting in a torsional angle difference between the active and driven discs. The elastic element then generates a counter-torque, offsetting the fluctuating component and stabilizing the torque transmitted to the reducer.

[0030] By adding a dual-mass flywheel as a self-damping electric drive system structure with a flexible transmission device to the traditional electric vehicle power system, the problem of uncontrollable torsional vibration in the traditional pure electric vehicle power transmission system is effectively solved, and the electromagnetic torque fluctuations emitted by the motor are effectively reduced; at the same time, due to the introduction of new rotational inertia and torsional stiffness parameters, the natural frequency of the entire system and the vibration modes of each order of the system are changed, thereby realizing the adjustment of the inherent characteristics.

[0031] In one embodiment, the radius of the active disk is 150 mm, the radius of the driven disk is 120 mm, and the moment of inertia of the active disk is 0.089 kg·m 2 The moment of inertia of the driven disc is 0.051 kg·m 2 , the torsional stiffness is 570Nm / rad, and the damping is 8.5Nm·s / rad.

[0032] Compared with related technologies, the innovation of the dual-mass flywheel lies in that it can simultaneously achieve wide-band vibration reduction and adjustment of the system's inherent characteristics through the combination of mechanical inertia and elastic damping. Other solutions mostly focus on single functions such as vibration reduction or compensation. In terms of comprehensive performance, the dual-mass flywheel has more advantages in electric drive systems.

[0033] See Figures 2 to 9 In order to further verify the effect of the adjustment of the inherent characteristics of the electric passenger vehicle drive system in the above embodiment, the present application also provides a method for verifying the inherent characteristics of the electric passenger vehicle drive system, such as Figure 2 As shown, the method includes the following steps S100 to S300:

[0034] S100, establishing a dynamic model of each component of the electric passenger vehicle drive system;

[0035] The electric passenger vehicle drive system includes a drive motor, a secondary reducer gear transmission assembly, a wheel axle, and a wheel connected in sequence; a dual-mass flywheel is connected between the drive motor and the transmission assembly, and the dual-mass flywheel includes a driving disc, an elastic damping device, and a driven disc connected in sequence;

[0036] In an exemplary embodiment, step S100 includes steps S110 to S130:

[0037] S110, establishing the electromagnetic coupling model of the drive motor; this step specifically includes:

[0038] S111 , establishing an electromagnetic coupling model of the drive motor in a natural coordinate system.

[0039] S112. Transform the electromagnetic coupling model from a natural coordinate system to a synchronously rotating coordinate system.

[0040] S113. Establish the voltage equation, magnetic flux equation and electromagnetic torque equation in the synchronous rotating coordinate system through transformation equations.

[0041] In a specific embodiment, the model of the permanent magnet synchronous motor in the natural coordinate system is first converted into a synchronous rotating coordinate system through the coordinate transformation equation to facilitate the subsequent vector control of the permanent magnet synchronous motor, and then an electromagnetic coupling model of the permanent magnet synchronous motor is established to obtain the dynamic characteristics of the electromagnetic torque; then, the lumped mass method is used to establish a dynamic model of the elastic force transmission in the dual-mass flywheel, and a dynamic model of the dual-mass flywheel based on the Lagrange equation is established; finally, the meshing characteristics of a pair of gear pairs are used to establish a dynamic model of the secondary reducer including internal excitations of the gears such as meshing time-varying stiffness and meshing error.

[0042] Among them, to establish the electromagnetic coupling model of the permanent magnet synchronous motor, the voltage equation in the natural coordinate system must be clarified as follows: The magnetic flux equation in the natural coordinate system is: 3s =L 3s i 3s +ψ f ·F 3s (θ e );

[0043] In the above formula, the parameters such as flux linkage, phase voltage, resistance, current, inductance, etc. satisfy:

[0044]

[0045] According to the principle of electromechanical energy conversion, the electromagnetic torque T e Equal to the magnetic field energy storage to the mechanical angular displacement θ m The partial derivative of , so the electromagnetic torque equation is: In addition, the mechanical motion equation of the permanent magnet synchronous motor can be listed as follows: In order to facilitate the subsequent design of the controller to perform vector control on the permanent magnet synchronous motor and thus obtain electromagnetic torque, it is necessary to transform the mathematical model of the permanent magnet synchronous motor from the natural coordinate system to the synchronous rotating coordinate system. The transformation equation is: Among them, the transformation equation matrix is:

[0046] After transformation, the voltage equation and flux equation of the permanent magnet synchronous motor in the synchronous rotating coordinate system can be obtained:

[0047]

[0048] Substituting the two equations into the equation, we can get the complete voltage equation:

[0049]

[0050] At this point, the electromagnetic torque equation of the permanent magnet synchronous motor under electromagnetic coupling conditions can be obtained:

[0051]

[0052] Among them, T e is the electromagnetic torque of the motor, p n is the number of magnetic pole pairs, i d 、i q are the direct-axis and quadrature-axis currents of the motor, L d , L q are the direct-axis and quadrature-axis inductances of the motor, ψ f is the permanent magnet flux.

[0053] S120: Establishing a dynamic model of the dual-mass flywheel elastic force transmission. This step specifically includes:

[0054] S121 , respectively write torque transmission equations according to the driving disc, the elastic damping system, and the driven disc.

[0055] S122. Considering the two rotational inertias of the driving disk and the driven disk as one, a dynamic equation is written.

[0056] In one embodiment, a dynamic model of the dual-mass flywheel elastic force transmission dynamic system is subsequently established. The dual-mass flywheel consists of a driving disc, a driven disc, and an elastic damping system between the two discs. Therefore, considering the dual-mass flywheel from the driving disc side within the elastic transmission range, the equation is established as follows: Considering the dual-mass flywheel from the driven disc side within the elastic transmission range, the equation is:

[0057] The equation for the elastic force can be expressed by combining the torsional angular displacement difference and the torsional angular velocity difference between the active and driven disks with the torsional stiffness and torsional damping as follows: It is also necessary to consider the case where the transmitted torque exceeds the elastic force transmission range of the dual-mass flywheel. In this case, the elastic force does not participate in the transmission of torque, and the active and driven plates are regarded as a whole inertia. The equation can be expressed as:

[0058] At this point, we can obtain the complete dynamic equations of the dual-mass flywheel outside the elastic force transmission range and within the elastic force transmission range:

[0059] Among them, T e is the input torque on the active disc side, T f is the elastic force transmitted by the dual mass flywheel, T L is the load torque on the driven disc side, I f1 , I f2 are the rotational inertia of the active disk and the driven disk respectively, K f is the torsional stiffness of the elastic system, C f is the torsional damping of the elastic system.

[0060] S130: Establishing a dynamic model of the secondary reducer gear transmission assembly; this step specifically includes:

[0061] S131. Establishing meshing dynamics equations of a pair of gear pairs; wherein the meshing dynamics equations of the gear pairs include a meshing dynamics equation, a meshing relative displacement equation, and a meshing force equation of the pair of gear pairs.

[0062] S132. Establish the meshing dynamics equation of the two-stage reducer based on the meshing equation of a pair of gear pairs.

[0063] S133. Based on the gear meshing characteristics, equations for gear internal excitations such as time-varying meshing stiffness and meshing error are established.

[0064] In a specific embodiment, a gear pair meshing dynamics model including internal excitations such as time-varying meshing stiffness and meshing error and a two-stage reducer dynamics model are finally established, wherein the dynamic equation of the gear pair meshing can be expressed as:

[0065] Among them F y It is a key parameter, representing the meshing force when the driving and driven teeth in the gear pair are meshing. It can be specifically expressed by the gear meshing stiffness, meshing damping and the relative displacement between gears. The calculation equation of relative displacement is:

[0066]

[0067] Therefore, the gear meshing force can be expressed as:

[0068]

[0069] Therefore, the dynamic model of the two-stage reducer can be established based on the meshing dynamic model of a stack of gear pairs, where the driven gear of the first-stage gear pair and the driving gear of the second-stage gear pair are on the same gear shaft:

[0070]

[0071] Similarly, the key parameter in this model is the first-stage gear pair meshing force F y1 And the meshing force F of the second gear pair y2 , which can be specifically expressed by the gear meshing stiffness, meshing damping and relative displacement between the two gear pairs. The calculation equation for the relative displacement is:

[0072]

[0073] Therefore, the meshing force equations of the first-stage and second-stage gear pairs can be established respectively through the meshing relative displacement of the two-stage gear pairs:

[0074]

[0075] During the gear meshing process, there will be a periodic phenomenon of alternating single and double teeth meshing, which will cause the gear stiffness to change periodically with time during the meshing process. Therefore, the time-varying stiffness of gear meshing needs to be considered in the establishment of a dynamic model for analyzing dynamic characteristics. Its expression is:

[0076]

[0077] Similarly, there is meshing error in the gear, which is an internal excitation phenomenon like the time-varying mesh stiffness and is expressed as:

[0078] e m (t) = E t sin(2πω s t+ψ s )+E s sin(2πω m t+2πγ s );

[0079] At this point, the gear meshing dynamics model of the two-stage reducer including the internal excitation of the gear including the time-varying meshing stiffness and gear meshing error can be obtained:

[0080]

[0081] Among them, I1, I 23 I and I4 represent the moment of inertia of the first-stage gear pair driving gear and input shaft, the first-stage gear pair driven gear and the second-stage gear pair driving gear and intermediate shaft, the second-stage gear pair driven gear and output shaft, respectively. T in 、T L Represent the input torque and output torque of the secondary reducer respectively, R1, R2, R3, R4 represent the main and driven gear radii of the first and second stage gear pairs respectively, F y1 、F y2 Represent the gear meshing forces of the first-stage and second-stage gear pairs respectively.

[0082] Similarly, the key parameter in this model is the first-stage gear pair meshing force F y1 And the meshing force F of the second gear pair y2 , which can be specifically expressed by the gear meshing stiffness, meshing damping and relative displacement between the two gear pairs. The calculation equation for the relative displacement is:

[0083]

[0084] Therefore, the meshing force equations of the first-stage and second-stage gear pairs can be established respectively through the meshing relative displacement of the two-stage gear pairs:

[0085] During the gear meshing process, there will be a periodic phenomenon of alternating single and double teeth meshing, which will cause the gear stiffness to change periodically with time during the meshing process. Therefore, the time-varying stiffness of gear meshing needs to be considered in the establishment of a dynamic model for analyzing dynamic characteristics. Its expression is:

[0086]

[0087] Similarly, there is meshing error in the gear, which is an internal excitation phenomenon like the time-varying mesh stiffness and is expressed as:

[0088] e m (t) = E t sin(2πω s t+ψ s )+E s sin(2πω m t+2πγ s );

[0089] At this point, the gear meshing dynamics model of the two-stage reducer including the internal excitation of the gear including the time-varying meshing stiffness and gear meshing error can be obtained:

[0090]

[0091] Among them, I1, I 23 I and I4 represent the moment of inertia of the first-stage gear pair driving gear and input shaft, the first-stage gear pair driven gear and the second-stage gear pair driving gear and intermediate shaft, the second-stage gear pair driven gear and output shaft, respectively. T in 、T L Represent the input torque and output torque of the secondary reducer respectively, R1, R2, R3, R4 represent the main and driven gear radii of the first and second stage gear pairs respectively, F y1 、F y2 Represent the gear meshing forces of the first-stage and second-stage gear pairs respectively.

[0092] S200 , coupling the dynamic models of the components of the electric passenger vehicle drive system to each other and completing basic parameter transfer, and then performing time domain dynamic characteristic simulation.

[0093] In an exemplary embodiment, step S200 includes steps S210 to S220:

[0094] S210, determining input and output parameters associated with a dynamic model of each component of the electric passenger vehicle drive system;

[0095] Among them, the input parameters of the drive motor include the target speed and load torque, and its output parameters include electromagnetic torque and motor speed. The output parameters of the dual-mass flywheel include input torque and load torque, and its output parameters include output torque. The input parameters of the secondary reducer include input torque and load torque, and its output parameters include output torque.

[0096] Permanent magnet synchronous motors require two output parameters: the target speed, which is input to the control system, and the load torque, which is input to the motor torque model. The input torque to the dual-mass flywheel is the motor's output electromagnetic torque. The input torque to the secondary reducer is the calculated elastic torque of the dual-mass flywheel.

[0097] S220. Formulate working conditions for test targets of model joint debugging and display model operation results.

[0098] The proposed model's operating conditions involved a motor as the power source, with a target speed set to 2000 rpm and a load torque input of 50 Nm initially, which doubled after half the operating time. The operational results, along with the results of electromagnetic torque transfer to subsequent models, are shown in the accompanying figures.

[0099] S300: Establish a torsional vibration model of the electric passenger vehicle drive system, and solve the natural frequencies of each vibration mode of the electric passenger vehicle drive system.

[0100] In an exemplary embodiment, step S200 includes steps S310 to S320:

[0101] S310. Establish an eight-degree-of-freedom torsional vibration model including the drive motor, dual-mass flywheel, main reducer, reducer, differential, wheel axles and wheels, and equivalent inertia of the entire vehicle.

[0102] The torsional vibration model equation of the traditional power system of a pure electric vehicle with a dual-mass flywheel as a flexible transmission device is established. Its main internal components include a permanent magnet synchronous motor, a dual-mass flywheel, a reducer, a main reducer and differential, axles and wheels, and the equivalent inertia of the entire vehicle. The specific structure is shown in the attached figure. The following set of equations can be established:

[0103]

[0104] The meaning and values ​​of each parameter are shown in the following table:

[0105]

[0106]

[0107] S320. Write the eight-degree-of-freedom torsional vibration model equation in matrix form and give the contents of the mass matrix, stiffness matrix and damping matrix.

[0108] The inherent characteristics of the torsional vibration equation established by the structure proposed in the present invention are solved, wherein the eight-degree-of-freedom torsional vibration system equation containing the flexible transmission device is written in matrix form as follows:

[0109]

[0110] The mass matrix, stiffness matrix and damping matrix can be expressed as:

[0111] θ=[θ m θ f1 θ f2 θ1θ2θ g θ w θ v ] T ;

[0112]

[0113]

[0114] S330: Solve the eight-degree-of-freedom torsional vibration model equation to obtain the natural frequencies corresponding to each order vibration mode of the system.

[0115] In order to solve the inherent characteristics, the damping matrix needs to be removed and written as the undamped free vibration equation:

[0116]

[0117] Therefore, the solution of this equation can be written as:

[0118] (K-ω 2 M)θ=0;

[0119] The eigenvalues ​​are the natural frequencies of each order of the system, and the eigenvectors are the vibration modes of each order of the system. The following table shows the natural frequencies of each order of the system containing the flexible transmission device of the present invention:

[0120]

[0121]

[0122] In some embodiments, a conventional torsional vibration model equation of an electric vehicle powertrain system that does not include a dual-mass flywheel can also be established. Its main internal components include a permanent magnet synchronous motor, a reducer, a main reducer and differential, axles and wheels, and the equivalent inertia of the entire vehicle. The specific structure is shown in the accompanying figure. The following set of equations can be established:

[0123]

[0124] The meaning and values ​​of each parameter are shown in the following table:

[0125]

[0126]

[0127] The inherent characteristics of the torsional vibration equations established for the above-mentioned traditional structure and the structure proposed in the present invention are solved. The traditional six-degree-of-freedom torsional vibration system equation without a flexible transmission device is written in matrix form as follows:

[0128]

[0129] Each matrix can be expressed as:

[0130] θ=[θ m θ1θ2θ g θ w θ v ] T ;

[0131]

[0132]

[0133] In order to solve the inherent characteristics, it is necessary to remove the damping matrix in the torsional vibration system equation and write it as:

[0134]

[0135] The solution of this equation can be written as:

[0136] (K-ω 2 M)θ=0;

[0137] The eigenvalues ​​are the natural frequencies of the system at each order, and the eigenvectors are the vibration modes of the system at each order. The following table shows the natural frequencies of the traditional structural system without a flexible transmission device:

[0138]

[0139] The natural frequencies of each order of the traditional system are 0, 6.78, 21.62, 596.66, 2669.59, and 8138.46 Hz, while the natural frequencies of each order of the electric passenger vehicle drive system of the present application are 0, 1.75, 17.87, 31.03, 284.19, 583.70, 2626.10, and 8105.62 Hz, among which the proportion of low-frequency vibration is increased and the dynamic characteristics of the system are more stable.

[0140] Compared with related technologies, the inherent characteristics of traditional electric drive systems are determined by fixed parameters of components such as motors and reducers and cannot be adjusted; however, this application introduces new dynamic parameters (moment of inertia, stiffness, and damping) through a dual-mass flywheel, which can actively adjust the natural frequency and vibration mode of the system, providing a new technical path for optimizing the dynamic characteristics of electric drive systems. The elastic buffering and damping energy dissipation mechanism of the dual-mass flywheel can reduce the impact load during power transmission, making the power output of the vehicle smoother when starting and accelerating, and improving the driving experience. By adjusting parameters such as the moment of inertia, torsional stiffness, and damping coefficient of the dual-mass flywheel, it can adapt to the needs of different vehicle models, motor power, and driving conditions, with high flexibility.

[0141] The present application is described by way of some embodiments. It is understood by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present application. In addition, under the guidance of the present application, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application are within the scope protected by the present application.

Claims

1. An electric passenger vehicle drive system, characterized in that: The system comprises: A drive motor, a secondary speed reducer gear transmission assembly, an axle and wheels connected in sequence; Wherein, a dual-mass flywheel is connected between the drive motor and the secondary reducer gear transmission assembly, and the dual-mass flywheel includes a driving disc, an elastic damping device and a driven disc connected in sequence; Among them, the active disk is fixedly connected to the output shaft of the drive motor, and is used to receive the electromagnetic torque generated by the drive motor; the elastic damping device includes a torsional stiffness element and a damping element arranged between the active disk and the driven disk, and the driven disk is fixedly connected to the input shaft of the transmission assembly, and is used to output the torque buffered by the dual mass flywheel to the transmission assembly.

2. A method for verifying the inherent characteristics of an electric passenger vehicle drive system, characterized in that: The method comprises: Establish dynamic models of various components based on the electric passenger vehicle drive system; The electric passenger vehicle drive system includes a drive motor, a secondary reducer gear transmission assembly, a wheel axle, and a wheel connected in sequence; a dual-mass flywheel is connected between the drive motor and the transmission assembly, and the dual-mass flywheel includes a driving disc, an elastic damping device, and a driven disc connected in sequence; After coupling the dynamic models of the components of the electric passenger vehicle drive system to complete basic parameter transfer, a time domain dynamic characteristics simulation is performed; A torsional vibration model of the electric passenger vehicle drive system is established, and the natural frequencies of each vibration mode of the electric passenger vehicle drive system are solved.

3. The method for verifying the inherent characteristics of an electric passenger vehicle drive system according to claim 2, characterized in that: The establishment of a dynamic model based on the electric passenger vehicle drive system includes: Establishing the electromagnetic coupling model of the drive motor includes: Establishing an electromagnetic coupling model of the drive motor in a natural coordinate system; Transform the electromagnetic coupling model from the natural coordinate system to the synchronously rotating coordinate system; The voltage equation, magnetic flux equation and electromagnetic torque equation in the synchronous rotating coordinate system are established through transformation equations. Establishing the dual-mass flywheel elastic force transmission dynamics model includes: Writing torque transmission equations according to the driving disc, the elastic damping system, and the driven disc respectively; The dynamic equation is written by considering the two rotational inertias of the driving disk and the driven disk as one; Establishing the dynamic model of the secondary reducer gear transmission assembly includes: Establishing a meshing dynamics equation for a pair of gear pairs; wherein the meshing dynamics equation for the gear pair includes a meshing dynamics equation for the pair of gear pairs, a meshing relative displacement equation, and a meshing force equation; The meshing dynamic equation of the secondary reducer is established based on the meshing equation of a pair of gear pairs; Based on the gear meshing characteristics, equations for gear internal excitations such as time-varying meshing stiffness and meshing error are established.

4. The method for verifying the inherent characteristics of an electric passenger vehicle drive system according to claim 3, characterized in that: The method of coupling the dynamic models of the components of the electric passenger vehicle drive system to each other and completing the basic parameter transfer and then performing time domain dynamic characteristics simulation includes: Determining input and output parameters associated with the dynamic models of various components of the electric passenger vehicle drive system; wherein the input parameters of the drive motor include a target speed and a load torque, and its output parameters include an electromagnetic torque and a motor speed; the output parameters of the dual-mass flywheel include an input torque and a load torque, and its output parameters include an output torque; and the input parameters of the secondary reducer include an input torque and a load torque, and its output parameters include an output torque; Formulate working conditions to test targets for joint model debugging and present model operation results.

5. The method for verifying the inherent characteristics of an electric passenger vehicle drive system according to claim 4, characterized in that: The step of establishing a torsional vibration model of the electric passenger vehicle drive system and solving the natural frequencies of each vibration mode of the electric passenger vehicle drive system includes: An eight-degree-of-freedom torsional vibration model is established, including the drive motor, dual-mass flywheel, main reducer, reducer, differential, wheel axles and wheels, and the equivalent inertia of the entire vehicle. Write the eight-degree-of-freedom torsional vibration model equation in matrix form and give the contents of mass matrix, stiffness matrix and damping matrix; The eight-degree-of-freedom torsional vibration model equation is solved to obtain the natural frequencies corresponding to each vibration mode of the system.

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