Torque control method and device for four-wheel permanent magnet wheel hub motor

Abstract

The application relates to the technical field of vehicle control, and provides a torque control method and device for four-wheel permanent-magnet wheel hub motors.The four-wheel torque optimization distribution model is constructed by taking the minimization of tire utilization as an optimization target, taking the yaw moment Delta M z , the adhesion limit mu F zij and the wheel hub motor peak torque T ijmax as constraint conditions, and is solved to obtain the wheel hub motor required torque T ij ; the temperature change factor is introduced, the wheel hub motor torque control model and the wheel hub motor electromagnetic torque MTPA control model are respectively constructed, the electromagnetic characteristic parameters of the corresponding wheel hub motor are obtained based on the temperature of each wheel hub motor, the wheel hub motor torque control model and the wheel hub motor electromagnetic torque MTPA control model are utilized, and the motor output torque T Lij is solved, so that the torque control is performed on the four-wheel permanent-magnet wheel hub motor.Under the premise of considering the temperature change influence, the accurate torque control of the four-wheel independent driving permanent-magnet synchronous wheel hub motor is realized, and the reliability and high efficiency of the wheel hub motor in the electric vehicle are ensured.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, specifically to a torque control method and device for a four-wheel permanent magnet hub motor. Background Technology

[0002] In-wheel motor technology, by integrating the motor directly into the wheel, not only simplifies the mechanical transmission system and reduces the need for complex components such as traditional drive axles, differentials, and half-shafts, but also makes the overall vehicle structure more compact and the weight distribution more rational. This design not only improves space utilization efficiency but also significantly increases transmission efficiency and energy conversion rate. Furthermore, the high integration of in-wheel motors facilitates vehicle design and manufacturing, reduces production costs, and provides possibilities for modular and personalized customization of future automobiles. However, as this technology is increasingly adopted in practical applications, some potential problems have gradually emerged.

[0003] During prolonged continuous operation, hub motors are prone to heat accumulation, primarily due to the inability to quickly dissipate the heat generated inside the motor, leading to a continuous temperature rise. While the high power density and torque density of permanent magnet synchronous motors endow them with excellent power performance, they also make them more susceptible to temperature rise issues during operation. Changes in the motor's body temperature directly affect its key electromagnetic parameters, such as inductance and flux linkage, thereby altering the motor's operating characteristics. Material aging and decreased insulation performance under high-temperature environments accelerate motor performance degradation and shorten its lifespan. More seriously, temperature changes lead to reduced motor control precision, particularly a significant decrease in torque precision, which reflects the motor's average torque characteristics. This poses a significant technical challenge for electric vehicles requiring precise control.

[0004] In summary, to ensure the reliability and efficiency of hub motors in electric vehicles, a key technical challenge is how to achieve precise torque control of permanent magnet synchronous hub motors with independent four-wheel drive, while taking into account the effects of temperature changes. Summary of the Invention

[0005] In view of this, the embodiments of this application provide a torque control method and device for a four-wheel permanent magnet hub motor. Under the premise of considering the influence of temperature changes, it realizes precise torque control of the four-wheel independently driven permanent magnet synchronous hub motor, ensuring the reliability and efficiency of the hub motor in electric vehicles.

[0006] The first aspect of this application provides a torque control method for a four-wheel permanent magnet hub motor, comprising:

[0007] With minimizing tire utilization as the optimization objective, and yaw moment ΔM z Adhesion limit μFzij and the peak torque T of the hub motor ijmax As constrained, a four-wheel torque optimization distribution model is constructed;

[0008] Solving the four-wheel torque optimization distribution model yields the required torque T for the hub motor. ij ;

[0009] Introducing temperature variation factors, we construct a hub motor torque control model and a hub motor electromagnetic torque MTPA control model, respectively.

[0010] Based on the temperature of each hub motor, the electromagnetic characteristic parameters of the corresponding hub motor are obtained;

[0011] Based on the aforementioned electromagnetic characteristic parameters, the motor output torque T is calculated using the hub motor torque control model and the hub motor electromagnetic torque MTPA control model. Lij ;

[0012] Based on the motor output torque T Lij Torque control is performed on the permanent magnet hub motors of the four wheels respectively;

[0013] Where ij represent the left front wheel fl, the right front wheel fr, the left rear wheel rl, and the right rear wheel rr, respectively.

[0014] A second aspect of this application provides a torque control device for a four-wheel permanent magnet hub motor, comprising:

[0015] The four-wheel torque optimization distribution model construction module is used to minimize tire utilization as the optimization objective, with yaw moment ΔM as the yaw moment. z Adhesion limit μF zij and the peak torque T of the hub motor ijmax As constrained, a four-wheel torque optimization distribution model is constructed;

[0016] The hub motor torque demand calculation module is used to solve the four-wheel torque optimization distribution model to obtain the hub motor torque demand T. ij ;

[0017] The hub motor torque control model construction module is used to introduce temperature change factors and construct hub motor torque control model and hub motor electromagnetic torque MTPA control model respectively;

[0018] The electromagnetic characteristic parameter acquisition module is used to acquire the electromagnetic characteristic parameters of each hub motor based on the temperature of each hub motor.

[0019] The motor output torque calculation module is used to calculate the motor output torque T based on the electromagnetic characteristic parameters, using the hub motor torque control model and the hub motor electromagnetic torque MTPA control model.Lij ;

[0020] The control module is used to control the output torque T of the motor. Lij Torque control is performed on the permanent magnet hub motors of the four wheels respectively;

[0021] Where ij represent the left front wheel fl, the right front wheel fr, the left rear wheel rl, and the right rear wheel rr, respectively.

[0022] A third aspect of this application provides an electronic device including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the electronic device implements the torque control method for a four-wheel permanent magnet hub motor as provided in the first aspect of this application.

[0023] A fourth aspect of this application provides a computer program product including a computer program that, when run, causes the method described in the first aspect of this application to be performed.

[0024] The torque control method for a four-wheel permanent magnet hub motor provided in the first aspect of this application constructs a four-wheel torque optimization distribution model with the goal of minimizing tire utilization and combined with yaw moment, adhesion limit, and hub motor peak torque as constraints. It also introduces temperature variation factors to construct a hub motor torque control model and a hub motor electromagnetic torque (MTPA) control model. This method not only ensures optimal drive force distribution under various driving conditions, improving vehicle performance and safety, but also solves the performance degradation and shortened lifespan problems caused by heat accumulation in traditional hub motors. It enhances the reliability, durability, and efficiency of the motor under different temperature environments, thereby significantly improving the overall operating efficiency and user experience of electric vehicles.

[0025] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic flowchart of a torque control method for a four-wheel permanent magnet hub motor provided in an embodiment of this application;

[0028] Figure 2This is a schematic diagram of the vehicle dynamics model;

[0029] Figure 3 This is a schematic flowchart of a torque control method for a four-wheel permanent magnet hub motor provided in another embodiment of this application;

[0030] Figure 4 This is a schematic flowchart of a torque control method for a four-wheel permanent magnet hub motor provided in another embodiment of this application;

[0031] Figure 5 This is a schematic diagram of the torque control device for a four-wheel permanent magnet hub motor provided in an embodiment of this application;

[0032] Figure 6 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0033] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0034] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0035] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0036] The torque control method for four-wheel permanent magnet hub motors provided in this application embodiment can be executed by the processor of an electronic device when running a computer program with corresponding functions. By constructing a four-wheel torque optimization distribution model with the goal of minimizing tire utilization and combined with yaw moment, adhesion limit, and hub motor peak torque as constraints, and by introducing temperature change factors to construct hub motor torque control model and hub motor electromagnetic torque MTPA control model, this method not only ensures optimal drive force distribution under various driving conditions, improving vehicle performance and safety, but also solves the problem of performance degradation and shortened lifespan caused by heat accumulation in traditional hub motors, enhancing the reliability and durability of the motor under different temperature environments, thereby significantly improving the overall operating efficiency and user experience of electric vehicles.

[0037] like Figure 1 As shown, the torque control method for a four-wheel permanent magnet hub motor provided in this application embodiment includes the following steps S101 to S106:

[0038] Step S101: With minimizing tire utilization as the optimization objective, and using the yaw moment ΔM... z Adhesion limit μF zij and the peak torque T of the hub motor ijmax A four-wheel torque optimization distribution model is constructed based on the constraints.

[0039] Step S102: Solve the four-wheel torque optimization distribution model to obtain the required torque T of the hub motor. ij .

[0040] Step S103: Introduce temperature change factors and construct the hub motor torque control model and the hub motor electromagnetic torque MTPA control model respectively.

[0041] Step S104: Based on the temperature of each hub motor, obtain the electromagnetic characteristic parameters of the corresponding hub motor.

[0042] Step S105: Based on the electromagnetic characteristic parameters, using the hub motor torque control model and the hub motor electromagnetic torque MTPA control model, solve for the motor output torque T. Lij .

[0043] Step S106, based on the motor output torque T Lij Torque control is performed on the permanent magnet hub motors of the four wheels respectively.

[0044] Where ij represent the left front wheel fl, the right front wheel fr, the left rear wheel rl, and the right rear wheel rr, respectively.

[0045] In one embodiment, the four-wheel torque optimization distribution model is as follows:

[0046]

[0047] Where minJ is the minimum tire utilization rate, C ij F represents the weighting coefficient for each wheel. xij F is the longitudinal driving force of the wheel. zij For the vertical load F exerted on the wheel by the ground, xfl F xfr F xrl F xrr These represent the longitudinal forces on the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively; μ is the coefficient of adhesion; r is the radius of the wheel; and F... x d represents the total driving force, and d represents the distance between the two wheels.

[0048] In application, based on the vehicle dynamics model and relationship diagram (see [link]). Figure 2 Given the total driving force F of the car x Additional yaw moment ΔM z The longitudinal driving force of the four wheels satisfies the following relationship:

[0049] F x =F xfl +F xfr +F xrl +F xrr (Equation 1)

[0050]

[0051] Among them, F xfl F xfr F xrl F xrr The values ​​are the longitudinal forces (in N) on the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively, and d is the distance between the two wheels.

[0052] According to the tire model, the forces acting on the wheel satisfy the following relationship:

[0053]

[0054] Among them, T Lij T is the output torque of the motor, r is the radius of the wheel, and T is the torque of the motor. fij F is the frictional torque acting on the wheel. zij The vertical load on the wheel from the ground is μ, where μ is the coefficient of adhesion, and ω is the coefficient of friction. ij J is the wheel's rotational speed (rad / s). wij Let represent the moment of inertia of the hub motor, which is the moment of inertia of the wheel about its own axis (including the wheel and the hub motor). ij represent the left front wheel fl, right front wheel fr, left rear wheel rl, and right rear wheel rr, respectively.

[0055] When the vehicle is in motion, the load transfer caused by lateral and longitudinal acceleration, as well as the load transfer caused by roll and pitch motion, will all increase the vertical load F. z The change refers to the situation where, under straight-ahead conditions, lateral acceleration is ignored. According to the vehicle dynamics model, the vertical load and the vehicle's acceleration under straight-ahead conditions have the following relationship:

[0056]

[0057] Among them l f l is the distance from the vehicle's center of gravity to the front axle. r h is the distance from the vehicle's center of gravity to the rear axle, and h is the height from the vehicle's center of gravity to the ground.

[0058] In the torque distribution process, the most fundamental requirement is that the distribution result can meet the target additional yaw moment of the entire vehicle, thereby improving vehicle handling stability. Tire utilization rate is used as an evaluation index for vehicle stability; the lower the utilization rate, the higher the vehicle's stability. Therefore, the optimization target is the tire utilization rate of all four wheels, with the yaw moment ΔM as the metric. z Adhesion limit and peak torque T of hub motor ijmax As constraints, the four-wheel torque optimization distribution model of this embodiment is constructed (i.e., Equation 5).

[0059] The four-wheel torque optimization distribution model constructed in this application aims to minimize tire utilization. The model solves for the required torque of each wheel through a quadratic programming method, while taking into account constraints such as total driving force, yaw moment, and adhesion limit. This not only helps to extend tire life and reduce maintenance costs, but also improves vehicle safety and driving stability, reflecting a dual focus on user safety and economic benefits.

[0060] In one embodiment, the hub motor torque control model is as follows:

[0061]

[0062] Among them, L dij (T) and L qij (T) represent the d-axis inductance and q-axis inductance corresponding to temperature T, respectively, and ψ rij (T) represents the permanent magnet flux linkage corresponding to temperature T, i qij P is the q-axis current. nij is the number of magnetic pole pairs.

[0063] The hub motor torque control model in this application directly relates to temperature and electromagnetic characteristic parameters, allowing for dynamic adjustment of the torque control strategy based on real-time temperature. This method simplifies control system design, improves the timeliness and accuracy of data acquisition, and ensures the consistency and reliability of motor performance under different temperature environments, thereby enhancing the overall flexibility and response speed of the system.

[0064] In one embodiment, the hub motor electromagnetic torque MTPA control model is as follows:

[0065]

[0066] Among them, T eij P is the electromagnetic torque of the motor. nij L is the number of magnetic pole pairs. dij (T) and L qij (T) represent the d-axis inductance and q-axis inductance corresponding to temperature T, respectively, and ψ rij (T) represents the permanent magnet flux linkage corresponding to temperature T, i dij Let i be the d-axis current. qij This is the q-axis current.

[0067] The in-wheel motor electromagnetic torque MTPA control model proposed in this application optimizes the ratio of d-axis and q-axis currents to obtain the maximum electromagnetic torque under given current conditions, thereby improving motor efficiency and power density, reducing unnecessary energy loss, and ensuring that the motor can maintain efficient operation over a wide operating range. This is of great significance for improving the range and economy of electric vehicles.

[0068] In applications, based on the permanent magnet synchronous motor model, the electromagnetic torque equation of a single motor can be expressed as:

[0069]

[0070] Among them, P nij i is the number of magnetic pole pairs. dij and L qij Let ψ be the d-axis inductance and the q-axis inductance. rij For permanent magnet flux linkage, i dij and i qij Let i be the d-axis current and q-axis current. From Equation 5, it can be seen that controlling the permanent magnet synchronous motor only requires controlling the current i on its input quadrature axes, i.e., the d and q axes. dij and i qij That's all.

[0071] Similarly, based on the in-wheel motor motion model, the dynamic equation of the permanent magnet synchronous in-wheel motor can be expressed as:

[0072]

[0073] Among them, T Lij R is the output torque of the motor. Ωij ω is the damping coefficient. rij J is the rotor rotational angular velocity. wij This represents the rotational inertia of the hub motor.

[0074] As can be seen from the above motor model, the torque control of a permanent magnet synchronous motor only requires controlling the current i along the dq axis. dij and i qij For control purposes, a feedforward torque reference current distribution strategy is adopted. Based on the motor's average torque characteristics, the motor's required torque and actual speed are directly used as inputs to output the optimal dq-axis reference current point i. dij and i qij Based on this, we consider incorporating the influence of motor temperature into the feedforward torque reference current distribution strategy.

[0075] In typical permanent magnet synchronous motor vector control, when the motor is operating in the constant torque region, MTPA (maximum torque-to-current ratio) curve control is often used. As the motor speed or torque increases, field weakening control methods are required.

[0076] Without field weakening control, based on the MTPA control curve, a current distribution model considering the temperature effect is constructed, and the dq-axis current distribution relationship under the influence of motor temperature can be obtained:

[0077]

[0078] The required torque T input to the motor during MTPA control ij Since it is related to the dq axis current, after introducing the temperature change factor, a hub motor torque control model considering the temperature effect can be obtained:

[0079]

[0080] Among them, L dij (T) and L qij (T) represent the d-axis inductance and q-axis inductance corresponding to temperature T, respectively, and ψ rij (T) represents the permanent magnet flux at temperature T.

[0081] Based on the electromagnetic torque equation of a permanent magnet synchronous motor, and considering the influence of temperature changes, the electromagnetic torque MTPA control model for the hub motor can be obtained, and its mathematical expression is as follows:

[0082]

[0083] like Figure 3 As shown, in one embodiment, step S105 includes the following steps S201 to S204:

[0084] Step S201: Input the electromagnetic characteristic parameters into the hub motor torque control model to obtain the q-axis current i. qij .

[0085] Step S202: Based on the dq-axis current distribution relationship, according to the q-axis current i qij Calculate the d-axis current i dij .

[0086] Step S203: Convert the q-axis current i qij and d-axis current i dij Input the hub motor electromagnetic torque MTPA control model and calculate the motor electromagnetic torque T. eij .

[0087] Step S204: Adjust the electromagnetic torque T of the motor. eij Substituting the equations of motion of the permanent magnet synchronous hub motor, the output torque T of the motor can be solved. Lij .

[0088] This application embodiment utilizes electromagnetic characteristic parameters to calculate the q-axis current through a hub motor torque control model, and calculates the d-axis current based on the dq-axis current distribution relationship. These current values ​​are then input into the hub motor electromagnetic torque MTPA control model to solve for the motor electromagnetic torque. This process achieves precise control of the motor output torque, ensuring efficient torque output even under temperature fluctuations, effectively improving energy utilization efficiency and system response speed.

[0089] In one embodiment, the electromagnetic torque T of the motor eij Substituting the equations of motion of the permanent magnet synchronous hub motor, the output torque T of the motor can be solved. Lij ,include:

[0090] The electromagnetic torque T of the motor eij Substituting into Equation 7, we can solve for the motor output torque T. Lij ;

[0091] Among them, R Ωij ω is the damping coefficient. rij J is the rotor rotational angular velocity. wij This represents the rotational inertia of the hub motor.

[0092] In one embodiment, the electromagnetic characteristic parameters of the corresponding hub motor are obtained based on the temperature of each hub motor, including:

[0093] Collect the temperature of each wheel hub motor;

[0094] Based on the temperature-electromagnetic property table, the electromagnetic property parameters are obtained, including the d-axis inductance and q-axis inductance L corresponding to temperature T.dij (T) and L qij (T), and the permanent magnet flux linkage ψ corresponding to temperature T. rij (T). The temperature-electromagnetic properties table was obtained through pre-calibration.

[0095] In one embodiment, it also includes:

[0096] Collect driver operation information and vehicle driving status information to obtain the total driving force F of the vehicle. x .

[0097] This application embodiment determines the total driving force of the vehicle by collecting the driver's operation information and the vehicle's driving status information. This approach enables the control system to predict driving intentions and adjust torque output accordingly, improving the quality of human-machine interaction, enhancing the driving experience, and providing strong support for energy-saving and safe driving.

[0098] In one embodiment, it also includes:

[0099] The motor output torque T Lij Substitute into the formula

[0100]

[0101] Calculate the wheel rotation speed ω ij ;

[0102] According to the formula Calculate the acceleration a of the wheel. x ;

[0103] Wherein, the wheel rotation speed ω ij and the acceleration a of the wheel x The data is stored in the data acquisition and processing module and used for the next round of motor output torque T. Lij The calculation.

[0104] This application embodiment calculates the wheel speed and acceleration by performing dynamic equations on the motor output torque, thus realizing closed-loop control. This feedback mechanism improves the system's stability and response speed, ensuring that the vehicle maintains good handling performance under various road conditions. It also provides an accurate data basis for the next round of torque control, forming a continuous optimization process.

[0105] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0106] This application also provides a torque control device for a four-wheel permanent magnet hub motor, used to execute the steps in the above-described torque control method embodiments for a four-wheel permanent magnet hub motor. The torque control device for the four-wheel permanent magnet hub motor can be a virtual appliance in an electronic device, run by the processor of the electronic device, or it can be the electronic device itself.

[0107] like Figure 4 As shown, in one embodiment, the torque control method flow for a four-wheel permanent magnet hub motor is as follows:

[0108] With minimizing tire utilization as the optimization objective, and yaw moment ΔM z Adhesion limit μF zij and the peak torque T of the hub motor ijmax A four-wheel torque optimization distribution model is constructed based on the constraints.

[0109] Solving the four-wheel torque optimization distribution model yields the required torque T for the hub motor. ij .

[0110] Introducing temperature variation factors, we constructed a hub motor torque control model and a hub motor electromagnetic torque MTPA control model, respectively.

[0111] Based on the temperature of each hub motor, the electromagnetic characteristic parameters of the corresponding hub motor are obtained.

[0112] The electromagnetic characteristic parameters are input into the hub motor torque control model to obtain the q-axis current i. qij ;

[0113] Based on the dq-axis current distribution relationship, according to the q-axis current i qij Calculate the d-axis current i dij ;

[0114] The q-axis current i qij and d-axis current i dij Input the hub motor electromagnetic torque MTPA control model and calculate the motor electromagnetic torque T. eij ;

[0115] The electromagnetic torque T of the motor eij Substituting the equations of motion of the permanent magnet synchronous hub motor, the output torque T of the motor can be solved. Lij .

[0116] Based on the motor output torque T Lij Torque control is performed on the permanent magnet hub motors of the four wheels respectively.

[0117] The motor output torque T Lij Substitute into the formula

[0118]

[0119] Calculate the wheel rotation speed ω ij ;

[0120] According to the formula Calculate the acceleration a of the wheel. x ;

[0121] Wherein, the wheel rotation speed ω ij and the acceleration a of the wheel x The data is stored in the data acquisition and processing module and used for the next round of motor output torque T. Lij The calculation.

[0122] like Figure 5 As shown in the embodiment of this application, the torque control device 100 for a four-wheel permanent magnet hub motor includes:

[0123] The four-wheel torque optimization distribution model construction module 101 is used to minimize tire utilization as the optimization objective and to optimize the yaw moment ΔM. z Adhesion limit μF zij and the peak torque T of the hub motor ijmax As constrained, a four-wheel torque optimization distribution model is constructed;

[0124] The hub motor torque demand calculation module 102 is used to solve the four-wheel torque optimization distribution model to obtain the hub motor torque demand T. ij ;

[0125] The hub motor torque control model construction module 103 is used to introduce temperature change factors and construct the hub motor torque control model and the hub motor electromagnetic torque MTPA control model respectively.

[0126] The electromagnetic characteristic parameter acquisition module 104 is used to acquire the electromagnetic characteristic parameters of the corresponding hub motor based on the temperature of each hub motor.

[0127] The motor output torque calculation module 105 is used to calculate the motor output torque T based on electromagnetic characteristic parameters, using the hub motor torque control model and the hub motor electromagnetic torque MTPA control model. Lij ;

[0128] Control module 106 is used to control the output torque T of the motor. Lij Torque control is performed on the permanent magnet hub motors of the four wheels respectively;

[0129] Where ij represent the left front wheel fl, the right front wheel fr, the left rear wheel rl, and the right rear wheel rr, respectively.

[0130] In applications, the modules in the torque control device of a four-wheel permanent magnet hub motor can be software program modules, or they can be implemented through different logic circuits integrated in a processor, or they can be implemented through multiple distributed processors.

[0131] like Figure 6 As shown, this application embodiment also provides an electronic device 200, including: at least one processor 201 ( Figure 6 The diagram shows only one processor, memory 202, and computer program 203 stored in memory 202 and executable on at least one processor 201. When processor 201 executes computer program 203, it implements the steps in the various method embodiments described above.

[0132] In applications, electronic devices may include, but are not limited to, processors and memory. Those skilled in the art will understand that... Figure 6 This is merely an example of an electronic device and does not constitute a limitation on the electronic device. It may include more or fewer components than shown, or a combination of certain components, or different components.

[0133] In applications, the processor can be a Central Processing Unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0134] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0135] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps described in the various method embodiments above.

[0136] This application provides a computer program product, including a computer program, which, when run on an electronic device, enables the electronic device to perform the steps described in the various method embodiments above.

[0137] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0138] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0139] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0140] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0141] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A torque control method for a four-wheel permanent magnet hub motor, characterized in that, include: With minimizing tire utilization as the optimization objective, and yaw moment ΔM z Adhesion limit μF zij and hub motor peak torque T ijmax As constrained, a four-wheel torque optimization distribution model is constructed; Solving the four-wheel torque optimization distribution model yields the required torque T for the hub motor. ij ; Introducing temperature variation factors, we construct a hub motor torque control model and a hub motor electromagnetic torque MTPA control model, respectively. Based on the temperature of each hub motor, the electromagnetic characteristic parameters of the corresponding hub motor are obtained; Based on the aforementioned electromagnetic characteristic parameters, the motor output torque T is calculated using the hub motor torque control model and the hub motor electromagnetic torque MTPA control model. Lij ; Based on the motor output torque T Lij Torque control is performed on the permanent magnet hub motors of the four wheels respectively; Where ij represent the left front wheel fl, the right front wheel fr, the left rear wheel rl, and the right rear wheel rr, respectively.

2. The torque control method for a four-wheel permanent magnet hub motor as described in claim 1, characterized in that, Based on the electromagnetic characteristic parameters, the output torque T of the motor is solved using the hub motor torque control model and the hub motor electromagnetic torque MTPA control model. Lij ,include: The electromagnetic characteristic parameters are input into the hub motor torque control model to obtain the q-axis current i. qij ; Based on the dq-axis current distribution relationship, according to the q-axis current i qij Calculate the d-axis current i dij ; The q-axis current i qij and the d-axis current i dij Input the hub motor electromagnetic torque MTPA control model and calculate the motor electromagnetic torque T. eij ; The electromagnetic torque T of the motor eij Substituting the equations of motion of the permanent magnet synchronous hub motor, the output torque T of the motor can be solved. Lij .

3. The torque control method for a four-wheel permanent magnet hub motor as described in claim 2, characterized in that, The electromagnetic torque T of the motor eij Substituting the equations of motion of the permanent magnet synchronous hub motor, the output torque T of the motor can be solved. Lij ,include: The electromagnetic torque T of the motor eij Substitute into the formula Solve for the motor output torque T Lij ; Among them, R Ωij ω is the damping coefficient. rij J is the rotor rotational angular velocity. wij This represents the rotational inertia of the hub motor.

4. The torque control method for a four-wheel permanent magnet hub motor as described in claim 1, characterized in that, The optimal torque distribution model for the four wheels is as follows: Where minJ is the minimum tire utilization rate, C ij F represents the weighting coefficient for each wheel. xij F is the longitudinal driving force of the wheel. zij For the vertical load F exerted on the wheel by the ground, xfl F xfr F xrl F xrr These represent the longitudinal forces on the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively; μ is the coefficient of adhesion; r is the radius of the wheel; and F... x d represents the total driving force, and d represents the distance between the two wheels.

5. The torque control method for a four-wheel permanent magnet hub motor as described in claim 1, characterized in that, The hub motor torque control model is as follows: Among them, L dij (T) and L qij (T) represent the d-axis inductance and q-axis inductance corresponding to temperature T, respectively, and ψ rij (T) represents the permanent magnet flux linkage corresponding to temperature T, i qij P is the q-axis current. nij is the number of magnetic pole pairs.

6. The torque control method for a four-wheel permanent magnet hub motor as described in claim 1, characterized in that, The hub motor electromagnetic torque MTPA control model is as follows: Among them, T eij P is the electromagnetic torque of the motor. nij L is the number of magnetic pole pairs. dij (T) and L qij (T) represent the d-axis inductance and q-axis inductance corresponding to temperature T, respectively, and ψ rij (T) represents the permanent magnet flux linkage corresponding to temperature T, i dij Let i be the d-axis current. qij This is the q-axis current.

7. The torque control method for a four-wheel permanent magnet hub motor as described in claim 1, characterized in that, The process of obtaining the electromagnetic characteristic parameters of each hub motor based on its temperature includes: Collect the temperature of each wheel hub motor; Based on the temperature-electromagnetic property table, electromagnetic property parameters are obtained, including the d-axis inductance and q-axis inductance L corresponding to temperature T. dij (T) and L qij (T), and the permanent magnet flux linkage ψ corresponding to temperature T. rij (T).

8. The torque control method for a four-wheel permanent magnet hub motor as described in claim 1, characterized in that, Also includes: Collect driver operation information and vehicle driving status information to obtain the total driving force F of the vehicle. x .

9. The torque control method for a four-wheel permanent magnet hub motor as described in claim 1, characterized in that, Also includes: The motor output torque T Lij Substitute into the formula Calculate the wheel rotation speed ω ij ; According to the formula Calculate the acceleration a of the wheel. x ; Wherein, the rotational speed ω of the wheel ij and the acceleration a of the wheel x Used for the next round of motor output torque T Lij The calculation, J wij This is the moment of inertia of the hub motor, where r is the radius of the wheel, and T is the moment of inertia. fij It is the frictional torque acting on the wheel, F zij Let μ be the vertical load on the wheel from the ground, and μ be the coefficient of adhesion.

10. A torque control device for a four-wheel permanent magnet hub motor, characterized in that, include: The four-wheel torque optimization distribution model construction module is used to minimize tire utilization as the optimization objective, with yaw moment ΔM as the yaw moment. z Adhesion limit μF zij and hub motor peak torque T ijmax As constrained, a four-wheel torque optimization distribution model is constructed; The hub motor torque demand calculation module is used to solve the four-wheel torque optimization distribution model to obtain the hub motor torque demand T. ij ; The hub motor torque control model construction module is used to introduce temperature change factors and construct hub motor torque control model and hub motor electromagnetic torque MTPA control model respectively; The electromagnetic characteristic parameter acquisition module is used to acquire the electromagnetic characteristic parameters of each hub motor based on the temperature of each hub motor. The motor output torque calculation module is used to calculate the motor output torque T based on the electromagnetic characteristic parameters, using the hub motor torque control model and the hub motor electromagnetic torque MTPA control model. Lij ; The control module is used to control the output torque T of the motor. Lij Torque control is performed on the permanent magnet hub motors of the four wheels respectively; Where ij represent the left front wheel fl, the right front wheel fr, the left rear wheel rl, and the right rear wheel rr, respectively.

Images