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

Abstract

The invention relates to the technical field of vehicle control, and provides a torque control method and device for a four-wheel permanent magnet hub motor. Comprising the following steps: by taking tire utilization rate minimization as an optimization target and taking a yawing moment delta Mz, an adhesion limit mu Fzij and a hub motor peak torque Tijmax as constraint conditions, constructing a four-wheel torque optimal distribution model and solving the four-wheel torque optimal distribution model to obtain a hub motor demand torque Tij; introducing a temperature change factor, and respectively constructing a hub motor torque control model and a hub motor electromagnetic torque MTPA control model; and based on the temperature of each hub motor, electromagnetic characteristic parameters of the corresponding hub motor are obtained, a hub motor torque control model and a hub motor electromagnetic torque MTPA control model are utilized to solve a motor output torque TLij, and torque control is performed on the four-wheel permanent magnet hub motor. On the premise of considering the influence of temperature change, the accurate torque control of the four-wheel independently-driven permanent magnet synchronous hub motor is realized, and the reliability and high efficiency of the hub motor in an electric automobile are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and in particular to a torque control method and device for a four-wheel permanent magnet hub motor. Background Art

[0002] In-wheel motor technology integrates the motor directly into the wheel, which 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 vehicle structure more compact and the weight distribution more reasonable. This design not only improves the efficiency of space utilization, but also significantly improves the transmission efficiency and higher energy conversion rate. In addition, the high degree of integration of in-wheel motors also facilitates the design and manufacturing of vehicles, reduces production costs, and provides the possibility for modularization and personalized customization of future vehicles. However, with the promotion of this technology in practical applications, some potential problems have gradually emerged.

[0003] During long-term continuous operation, the hub motor is prone to heat accumulation. This is mainly because the heat generated inside the motor cannot be quickly dissipated, causing the temperature to continue to rise. For permanent magnet synchronous motors, although its high power density and high torque density give it excellent power performance, it also makes it more susceptible to temperature rise problems during operation. Changes in the temperature of the motor body will directly affect its key electromagnetic parameters, such as inductance and magnetic flux, and thus change the operating characteristics of the motor. Problems such as material aging and reduced insulation performance in high temperature environments will accelerate the decline of motor performance and shorten its service life. What's more serious is that temperature changes will lead to a decrease in motor control accuracy, especially the torque accuracy that reflects the average torque characteristics of the motor will drop significantly, which is a technical challenge that cannot be ignored for electric vehicles that require precise control.

[0004] In summary, in order to ensure the reliability and efficiency of the hub motor in electric vehicles, how to achieve precise torque control of the permanent magnet synchronous hub motor with four-wheel independent drive while taking into account the influence of temperature changes is a technical problem that needs to be solved. Summary of the invention

[0005] In view of this, an embodiment of the present application provides a torque control method and device for a four-wheel permanent magnet hub motor, which realizes precise torque control of the four-wheel independently driven permanent magnet synchronous hub motor while taking into account the influence of temperature changes, thereby ensuring the reliability and efficiency of the hub motor in electric vehicles.

[0006] A first aspect of an embodiment of the present application provides a torque control method for a four-wheel permanent magnet hub motor, comprising:

[0007] Taking the minimization of tire utilization as the optimization goal, the yaw moment ΔM z , Adhesion limit μFzij and the peak torque of the hub motor T ijmax As the constraint condition, the four-wheel torque optimization distribution model is constructed;

[0008] The four-wheel torque optimization distribution model is solved to obtain the required torque T of the hub motor: ij ;

[0009] The temperature change factor is introduced to build the wheel hub motor torque control model and the wheel hub motor electromagnetic torque MTPA control model respectively;

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

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

[0012] Based on the motor output torque T Lij The torque of the permanent magnet hub motors of the four wheels is controlled separately;

[0013] Among them, ij represents 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 an embodiment of the present application provides a torque control device for a four-wheel permanent magnet hub motor, comprising:

[0015] The four-wheel torque optimization distribution model building module is used to minimize the tire utilization rate and the yaw moment ΔM z , Adhesion limit μF zij and the peak torque of the hub motor T ijmax As the constraint condition, the four-wheel torque optimization distribution model is constructed;

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

[0017] The hub motor torque control model building module is used to introduce the temperature change factor and build the hub motor torque control model and the hub motor electromagnetic torque MTPA control model respectively;

[0018] An electromagnetic characteristic parameter acquisition module, used to acquire the electromagnetic characteristic parameters of the corresponding wheel hub motor based on the temperature of each wheel hub motor;

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

[0020] A control module is used for outputting a torque T of the motor based on the Lij The torque of the permanent magnet hub motors of the four wheels is controlled separately;

[0021] Among them, ij represents 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 an embodiment of the present application provides an electronic device, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein 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 the embodiment of the present application.

[0023] A fourth aspect of the embodiments of the present application provides a computer program product, including a computer program. When the computer program is executed, the method according to the first aspect of the embodiments of the present application is executed.

[0024] The first aspect of the embodiment of the present application provides a torque control method for four-wheel permanent magnet hub motors. By constructing a four-wheel torque optimization distribution model with the goal of minimizing tire utilization and combining yaw moment, adhesion limit and hub motor peak torque as constraints, and introducing temperature change factors to construct a hub motor torque control model and a hub motor electromagnetic torque MTPA control model, this method not only ensures the optimal driving force distribution under various driving conditions and improves vehicle performance and safety, but also solves the problems of performance degradation and shortened life of traditional hub motors due to heat accumulation problems, enhances the reliability, durability and efficiency of the motor in different temperature environments, thereby significantly improving the overall operating efficiency and user experience of electric vehicles.

[0025] It can be understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 It is a flow chart of a torque control method of a four-wheel permanent magnet hub motor provided in an embodiment of the present application;

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

[0029] Figure 3 It is a flow chart of a torque control method of a four-wheel permanent magnet hub motor provided by another embodiment of the present application;

[0030] Figure 4 It is a flow chart of a torque control method of a four-wheel permanent magnet hub motor provided by another embodiment of the present application;

[0031] Figure 5 It is a structural schematic diagram of a torque control device for four-wheel permanent magnet hub motors provided in an embodiment of the present application;

[0032] Figure 6 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

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

[0035] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0036] The torque control method for four-wheel permanent magnet hub motors provided in the embodiment of the present application 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 combining yaw moment, adhesion limit and hub motor peak torque as constraints, and introducing temperature change factors to construct a hub motor torque control model and a hub motor electromagnetic torque MTPA control model, this method not only ensures the optimal driving force distribution under various driving conditions and improves vehicle performance and safety, but also solves the problems of performance degradation and shortened life of traditional hub motors due to heat accumulation problems, enhances the reliability and durability of the motor in 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 of the four-wheel permanent magnet hub motor provided in the embodiment of the present application includes the following steps S101 to S106:

[0038] Step S101: Minimizing tire utilization is the optimization goal, and the yaw moment ΔM z , Adhesion limit μF zij and the peak torque of the hub motor T ijmax As the constraint condition, a four-wheel torque optimization distribution model is constructed.

[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: introducing the temperature change factor, and constructing the wheel hub motor torque control model and the wheel hub motor electromagnetic torque MTPA control model respectively.

[0041] Step S104: based on the temperature of each wheel hub motor, obtaining electromagnetic characteristic parameters of the corresponding wheel hub motor.

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

[0043] Step S106: Based on the motor output torque T Lij The torque of the permanent magnet hub motors of the four wheels is controlled separately.

[0044] Among them, ij represents 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:

[0046]

[0047] Among them, minJ is the minimum tire utilization rate, C ij is the weight coefficient of each wheel, F xij is the longitudinal driving force of the wheel, F zij F is the vertical load on the wheel from the ground, xfl 、F xfr 、F xrl 、F xrr are the longitudinal forces of the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively; μ is the adhesion coefficient; r is the radius of the wheel; F x is the total driving force, and d is the distance between the two wheels.

[0048] In the application, according to the vehicle dynamics model and relationship diagram (see Figure 2 ), the total driving force of the car is known to be F 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 (Formula 1)

[0050]

[0051] Among them, F xfl 、F xfr 、F xrl 、F xrr They are the longitudinal forces (unit: N) of 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 force on the wheel satisfies the following relationship:

[0053]

[0054] Among them, T Lij is the motor output torque, r is the radius of the wheel, T fij is the friction torque on the wheel, F zij is the vertical load on the wheel from the ground, μ is the adhesion coefficient, ω ij is the wheel speed (rad / s), J wij is the moment of inertia of the hub motor, that is, the moment of inertia of the wheel around its own axis (including the wheel and the hub motor). ij represents the left front wheel fl, the right front wheel fr, the left rear wheel rl, and the 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 rolling and pitching motions, will cause the vertical load F z Changes refer to the straight-ahead working condition. Ignoring the lateral acceleration, according to the vehicle dynamics model, the vertical load and the acceleration of the vehicle in the straight-ahead working condition have the following relationship:

[0056]

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

[0058] In the process of torque distribution, the most basic thing is that the distribution result can meet the target additional yaw moment of the whole vehicle, so that the vehicle handling stability is improved. The utilization rate of tires is used as the evaluation index of vehicle stability. The smaller the utilization rate, the higher the stability of the vehicle. Therefore, the tire rate of the four wheels is used as the optimization target, and the yaw moment ΔM is used as the optimization target. z , adhesion limit and wheel motor peak torque T ijmax As a constraint condition, the four-wheel torque optimization distribution model of this embodiment is constructed (i.e., Formula 5).

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

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

[0061]

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

[0063] The hub motor torque control model of the embodiment of the present application directly links temperature and electromagnetic characteristic parameters, allowing the torque control strategy to be dynamically adjusted according to the real-time temperature. This method simplifies the control system design, improves the timeliness and accuracy of data acquisition, ensures the consistency and reliability of motor performance under different temperature environments, and thus enhances the overall flexibility and response speed of the system.

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

[0065]

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

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

[0068] In application, according to the permanent magnet synchronous motor model, the electromagnetic torque equation of a single motor can be expressed as:

[0069]

[0070] Among them, P nij is the number of magnetic pole pairs, i dij and L qij is the d-axis inductance and q-axis inductance, ψ rij is the permanent magnet flux, i dij and i qij is the d-axis current and the q-axis current. As can be seen from equation 5, the control of the permanent magnet synchronous motor only needs to control the current i of the AC and DC axes, i.e., the dq axes, that is, the input current i dij and i qij That's it.

[0071] Similarly, according to the wheel hub motor motion model, the dynamic equation of the permanent magnet synchronous wheel hub motor can be expressed as:

[0072]

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

[0074] From the above motor model, it can be seen that the torque control of the permanent magnet synchronous motor only needs to control the current i of the dq axis dij and i qij Therefore, a feedforward torque reference current distribution strategy is adopted. According to the average torque characteristics of the motor, the required torque and the actual speed of the motor are directly used as input to output the optimal dq axis reference current point i dij and i qij Based on this, the influence of motor temperature is considered to be added into the feedforward torque reference current distribution strategy.

[0075] In general permanent magnet synchronous motor vector control, when the motor operates in the constant torque area, MTPA (maximum torque to current ratio) curve control is often used. As the motor speed increases or the torque increases, a weak magnetic control method needs to be further adopted.

[0076] In the absence of magnetic weakening control, based on the MTPA control curve, a current distribution model considering the influence of temperature 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 There is a connection with the dq axis current. After introducing the temperature change factor, the hub motor torque control model considering the temperature effect can be obtained:

[0079]

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

[0081] According to the permanent magnet synchronous motor electromagnetic torque equation, after considering the influence of temperature change, the hub motor electromagnetic torque MTPA control model can be obtained. The 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 wheel 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: Set the q-axis current i qij and the d-axis current i dij Input the MTPA control model of the wheel hub motor electromagnetic torque and calculate the motor electromagnetic torque T eij .

[0087] Step S204: The motor electromagnetic torque T eij Substitute into the permanent magnet synchronous hub motor dynamics equation and solve the motor output torque T Lij .

[0088] The embodiment of the present application utilizes electromagnetic characteristic parameters to calculate the q-axis current through the hub motor torque control model, and calculates the d-axis current based on the dq-axis current distribution relationship, and then inputs these current values ​​into the hub motor electromagnetic torque MTPA control model to solve the motor electromagnetic torque. This process achieves precise control of the motor output torque, ensuring that efficient torque output can be maintained even in the case of temperature fluctuations, effectively improving energy utilization efficiency and system response speed.

[0089] In one embodiment, the motor electromagnetic torque T eij Substitute into the permanent magnet synchronous hub motor dynamics equation and solve the motor output torque T Lij ,include:

[0090] The motor electromagnetic torque T eij Substitute into equation 7 and solve for the motor output torque T Lij ;

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

[0092] In one embodiment, based on the temperature of each wheel hub motor, obtaining the electromagnetic characteristic parameters of the corresponding wheel hub motor includes:

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

[0094] Based on the temperature-electromagnetic characteristic table, the electromagnetic characteristic parameters are obtained. The electromagnetic characteristic parameters include the d-axis inductance and q-axis inductance L corresponding to the temperature T.dij (T) and L qij (T), and the permanent magnet flux linkage ψ corresponding to temperature T rij (T). The temperature-electromagnetic characteristic table is pre-calibrated.

[0095] In one embodiment, it further includes:

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

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

[0098] In one embodiment, it further includes:

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

[0100]

[0101] Calculate the wheel speed ω ij ;

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

[0103] Among them, the wheel speed ω ij and the wheel acceleration a x Stored in the data acquisition and processing module, used for the next round of motor output torque T Lij Calculation.

[0104] The embodiment of the present application achieves closed-loop control by calculating the dynamic equation of the motor output torque to obtain the wheel speed and acceleration. This feedback mechanism improves the stability and response speed of the system, ensuring that the vehicle can maintain 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 size of the serial numbers of the steps in the above embodiments does not mean 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 the present application.

[0106] The present application also provides a torque control device for a four-wheel permanent magnet hub motor, which is used to execute the steps in the above-mentioned torque control method embodiment of the four-wheel permanent magnet hub motor. The torque control device for a four-wheel permanent magnet hub motor can be a virtual appliance in an electronic device, which is run by a 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 of the four-wheel permanent magnet hub motor is as follows:

[0108] Taking the minimization of tire utilization as the optimization goal, the yaw moment ΔM z , Adhesion limit μF zij and the peak torque of the hub motor T ijmax As the constraint condition, a four-wheel torque optimization distribution model is constructed.

[0109] Solve the four-wheel torque optimization distribution model to obtain the required torque T of the hub motor ij .

[0110] The temperature change factor is introduced to construct the hub motor torque control model and the hub motor electromagnetic torque MTPA control model respectively.

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

[0112] The electromagnetic characteristic parameters are input into the wheel 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 the d-axis current i dij Input the MTPA control model of the wheel hub motor electromagnetic torque and calculate the motor electromagnetic torque T eij ;

[0115] The motor electromagnetic torque T eij Substitute into the permanent magnet synchronous hub motor dynamics equation and solve the motor output torque T Lij .

[0116] Based on the motor output torque T Lij The torque of the permanent magnet hub motors of the four wheels is controlled separately.

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

[0118]

[0119] Calculate the wheel speed ω ij ;

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

[0121] Among them, the wheel speed ω ij and the wheel acceleration a x Stored in the data acquisition and processing module, used for the next round of motor output torque T Lij Calculation.

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

[0123] The four-wheel torque optimization distribution model building module 101 is used to minimize the tire utilization rate as the optimization goal and to use the yaw moment ΔM z , Adhesion limit μF zij and the peak torque of the hub motor T ijmax As the constraint condition, the four-wheel torque optimization distribution model is constructed;

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

[0125] The wheel hub motor torque control model building module 103 is used to introduce the temperature change factor and respectively build the wheel hub motor torque control model and the wheel hub motor electromagnetic torque MTPA control model;

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

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

[0128] The control module 106 is used to control the motor output torque T Lij The torque of the permanent magnet hub motors of the four wheels is controlled separately;

[0129] Among them, ij represents the left front wheel fl, the right front wheel fr, the left rear wheel rl, and the right rear wheel rr respectively.

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

[0131] like Figure 6 As shown, the embodiment of the present application further provides an electronic device 200, including: at least one processor 201 ( Figure 6 Only one processor is shown in the figure), a memory 202, and a computer program 203 stored in the memory 202 and executable on at least one processor 201, wherein the processor 201 implements the steps in the above-mentioned various method embodiments when executing the computer program 203.

[0132] In applications, electronic devices may include, but are not limited to, processors and memories. Those skilled in the art will appreciate that Figure 6 The electronic device is merely an example and does not limit the electronic device, and may include more or less components than those shown in the figure, or may combine certain components, or may include different components.

[0133] In applications, the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0134] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0135] The embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0136] An embodiment of the present application provides a computer program product, including a computer program. When the computer program product runs on an electronic device, the electronic device can implement the steps in the above-mentioned method embodiments when executing the computer program product.

[0137] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0138] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0139] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

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

[0141] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A torque control method for a four-wheel permanent magnet hub motor, characterized in that: include: Taking the minimization of tire utilization as the optimization goal, the yaw moment ΔM z , Adhesion limit μF zij and the peak torque of the hub motor T ijmax As the constraint condition, the four-wheel torque optimization distribution model is constructed; The four-wheel torque optimization distribution model is solved to obtain the required torque T of the hub motor ij ; The temperature change factor is introduced to build the wheel hub motor torque control model and the wheel hub motor electromagnetic torque MTPA control model respectively; Based on the temperature of each wheel hub motor, the electromagnetic characteristic parameters of the corresponding wheel hub motor are obtained; Based on the electromagnetic characteristic parameters, the motor output torque T is solved by using the wheel hub motor torque control model and the wheel hub motor electromagnetic torque MTPA control model. Lij ; Based on the motor output torque T Lij The torque of the permanent magnet hub motors of the four wheels is controlled separately; Among them, ij represents 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 of the four-wheel permanent magnet hub motor according to claim 1, characterized in that: Based on the electromagnetic characteristic parameters, the motor output torque T is solved by using the wheel hub motor torque control model and the wheel hub motor electromagnetic torque MTPA control model. Lij ,include: The electromagnetic characteristic parameters are input into the wheel 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 MTPA control model of the wheel hub motor electromagnetic torque and calculate the motor electromagnetic torque T eij ; The motor electromagnetic torque T eij Substitute into the permanent magnet synchronous hub motor dynamics equation and solve the motor output torque T Lij .

3. The torque control method of the four-wheel permanent magnet hub motor according to claim 2, characterized in that: The motor electromagnetic torque T eij Substitute into the permanent magnet synchronous hub motor dynamics equation and solve the motor output torque T Lij ,include: The motor electromagnetic torque T eij Substitute into the formula Solve for the motor output torque T Lij ; Among them, R Ωij is the damping coefficient, ω rij is the rotor rotation angular velocity, J wij is the rotational inertia of the hub motor.

4. The torque control method of four-wheel permanent magnet hub motor according to claim 1, characterized in that: The four-wheel torque optimization distribution model is: Among them, minJ is the minimum tire utilization rate, C ij is the weight coefficient of each wheel, F xij is the longitudinal driving force of the wheel, F zij F is the vertical load on the wheel from the ground. xfl 、F xfr 、F xrl 、F xrr are the longitudinal forces of the left front wheel, right front wheel, left rear wheel, and right rear wheel respectively, μ is the adhesion coefficient, r is the radius of the wheel, and F x is the total driving force, and d is the distance between the two wheels.

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

6. The torque control method of four-wheel permanent magnet hub motor according to claim 1, characterized in that: The hub motor electromagnetic torque MTPA control model is: Among them, T eij is the electromagnetic torque of the motor, P nij is the number of magnetic pole pairs, L dij (T) and L qij (T) are the d-axis inductance and q-axis inductance corresponding to temperature T, ψ rij (T) is the permanent magnet flux corresponding to temperature T, i dij is the d-axis current, i qij is the q-axis current.

7. The torque control method of four-wheel permanent magnet hub motor according to claim 1, characterized in that: The obtaining of electromagnetic characteristic parameters of the corresponding wheel hub motors based on the temperature of each wheel hub motor includes: Collect the temperature of each wheel hub motor; Based on the temperature-electromagnetic characteristic table, electromagnetic characteristic parameters are obtained, wherein the electromagnetic characteristic parameters include the d-axis inductance and the q-axis inductance L corresponding to the 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 of four-wheel permanent magnet hub motor according to claim 1, characterized in that: Also includes: Collect the driver's operating information and vehicle driving status information to obtain the total driving force F of the vehicle x .

9. The torque control method of four-wheel permanent magnet hub motor according to claim 1, characterized in that: Also includes: The motor output torque T Lij Substitute into the formula Calculate the wheel speed ω ij ; According to the formula Calculate the wheel acceleration a x ; Wherein, the rotation speed of the wheel ω ij and the wheel acceleration a x For the next round of motor output torque T Lij Calculation.

10. A torque control device for a four-wheel permanent magnet hub motor, characterized in that: include: The four-wheel torque optimization distribution model building module is used to minimize the tire utilization rate and the yaw moment ΔM z , Adhesion limit μF zij and the peak torque of the hub motor T ijmax As the constraint condition, the four-wheel torque optimization distribution model is constructed; The hub motor required torque calculation module is used to solve the four-wheel torque optimization distribution model to obtain the hub motor required torque T ij ; The hub motor torque control model building module is used to introduce the temperature change factor and build the hub motor torque control model and the hub motor electromagnetic torque MTPA control model respectively; An electromagnetic characteristic parameter acquisition module, used to acquire the electromagnetic characteristic parameters of the corresponding wheel hub motor based on the temperature of each wheel hub motor; The motor output torque calculation module is used to solve the motor output torque T based on the electromagnetic characteristic parameters using the wheel hub motor torque control model and the wheel hub motor electromagnetic torque MTPA control model. Lij ; A control module is used for outputting a torque T of the motor based on the Lij The torque of the permanent magnet hub motors of the four wheels is controlled separately; Among them, ij represents the left front wheel fl, the right front wheel fr, the left rear wheel rl, and the right rear wheel rr respectively.

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