A design method of an integrated permanent magnet synchronous electric drive system for an electric motorcycle

Abstract

The application relates to a kind of permanent magnet synchronous electric drive system integrated design methods for electric motorcycle, and belongs to the field of permanent magnet synchronous electric drive system.The method comprises the following steps: designing electromagnetic scheme and establishing electromagnetic simulation model; establishing the mechanical stress field simulation model of motor, and evaluating the mechanical stress of electromagnetic simulation model, if the evaluation is unqualified, then the electromagnetic simulation model parameters are redesigned; the reducer, driver selection and DC-DC design are carried out; the heat dissipation structure design of the machine shell is carried out; the electric drive system simulation model is established; the electromagnetic-thermal two-way coupling of electromagnetic simulation model and electric drive system simulation model is carried out; the electromagnetic results and temperature rise distribution diagram obtained by electromagnetic-thermal two-way coupling simulation are analyzed, if the temperature rise meets the expectation, then the final design scheme is output; if the temperature rise exceeds the expectation, then the heat dissipation channel of the machine shell is redesigned.The application can effectively improve the performance of the drive system and reduce the size of the system during the design process.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet synchronous electric drive systems, and relates to an integrated design method for a permanent magnet synchronous electric drive system for electric motorcycles. Background Technology

[0002] Electric motorcycles use a mid-mounted electric drive system that drives the rear wheel from below. To improve drive efficiency, multi-functional integrated electric drive systems have become a major research focus for manufacturers. Currently, the most common multi-functional integrated electric drive systems are three-in-one systems that integrate the controller, motor, and transmission system. For example, the prior art (CN114313094A) proposes a three-in-one integrated pure electric drive system for motorcycles, including a controller assembly. The bottom of the controller assembly is connected to the motor assembly, the output end of the motor assembly is connected to one end of the transmission system assembly, the other end of the transmission system assembly is connected to one side of the wheel, the other side of the wheel's shaft is connected to one end of the right arm, and the other end of the right arm is connected to the controller assembly. Firstly, this prior art does not include the power supply as a component of the integrated electric drive system; therefore, a separate power supply system is required when installing it on an electric motorcycle. Furthermore, the design process of the existing integrated electric drive system also has certain flaws.

[0003] Traditional integrated drive system design involves designing each component separately and then assembling them. This approach fails to consider the impact of heat generated by each component on other components. Temperature is a crucial indicator of the performance of permanent magnet synchronous motors, drivers, and DC-DC converters; excessively high temperatures can even damage components and cause localized demagnetization of permanent magnets. In other words, the integrated electric drive system obtained through existing separate design and assembly techniques often suffers from significantly lower overall performance than expected due to the temperature variations between the various components during operation. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide an integrated design method for a permanent magnet synchronous electric drive system for electric motorcycles, namely, a multi-physics field integrated design method based on electro-magnetism-mechanical-thermal fields, which improves space utilization while ensuring the performance of the drive system.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an integrated design method for a permanent magnet synchronous electric drive system for electric motorcycles, namely, a multi-physics field integrated design method based on electro-magnetism-mechanical-thermal fields, which improves space utilization while ensuring the performance of the drive system.

[0006] An integrated design method for a permanent magnet synchronous electric drive system for an electric motorcycle, the method comprising the following steps:

[0007] S1. Based on the finite element simulation platform, design the electromagnetic scheme and establish an electromagnetic simulation model;

[0008] S2. Based on the finite element simulation platform, establish a mechanical stress field simulation model of the motor and evaluate the mechanical stress of the electromagnetic simulation model. If the evaluation is unsatisfactory, return to S1 to redesign the electromagnetic simulation model parameters.

[0009] S3. Select reducers and drivers, and design DC-DC converters;

[0010] S4. Design the heat dissipation structure of the casing;

[0011] S5. Establish a simulation model of the electric drive system, including permanent magnet synchronous motor, driver, DC-DC converter, reducer, and housing, in the temperature field simulation of the finite element simulation platform.

[0012] S6. Based on the finite element simulation platform, the electromagnetic simulation model and the electric drive system simulation model are coupled in an electromagnetic-thermal bidirectional manner.

[0013] S7. Analyze the electromagnetic results and temperature rise distribution diagram obtained from the electromagnetic-thermal bidirectional coupling simulation. If the temperature rise meets expectations, output the final design scheme; if the temperature rise exceeds expectations, return to S4 to redesign the heat dissipation channel.

[0014] Furthermore, step S1 includes the following steps: S11: geometric structure design of the electromagnetic simulation model; S12: parameter setting in the electromagnetic simulation model; S13: storing the qualified simulation model.

[0015] Furthermore, step S2 includes the following steps: S21, static structural design; S22, engineering data design; S23, geometric structural design; S24, model establishment; S25, parameter setting; S26, parameter solving; S27, output results.

[0016] Further, step S5 includes the following steps: S51, geometric structure design of the three-dimensional simulation model of the electric drive system; S52, mesh design of the three-dimensional simulation model of the electric drive system; S53, parameter setting of the three-dimensional simulation model of the electric drive system; S54, parameter solving of the three-dimensional simulation model of the electric drive system; S55, data saving of the three-dimensional simulation model of the electric drive system.

[0017] Furthermore, in step S6, the Maxwell electromagnetic simulation implemented by the electromagnetic simulation model in step S1 and the Fluent thermal simulation of the three-dimensional simulation model of the electric drive system in step S5 are bidirectionally coupled, so that the motor-related losses of the electromagnetic simulation model are coupled into the model of the three-dimensional simulation model of the electric drive system. After calculating the temperature, the temperature is returned to the electromagnetic model, thereby updating the material loss curves corresponding to different temperatures of the electromagnetic model.

[0018] The beneficial effects of this invention are as follows:

[0019] The proposed integrated design method for permanent magnet synchronous electric drive systems for electric motorcycles solves the problem of unpredictable temperature rises caused by limited space during traditional integration processes. This is achieved through electro-magnetic-mechanical-thermal multi-physics coupling design during the design phase, which affects the performance of the drive system and can even lead to component damage. Using the design process described in this invention, the performance of the drive system can be effectively improved, the system size reduced, and a more reliable drive solution for electric motorcycles can be provided.

[0020] The design method of the present invention for the four-in-one permanent magnet synchronous electric drive system will not have any performance difference between the expected performance and the actual working performance due to the temperature effect during operation, which makes it easier for manufacturers and users to correctly evaluate the actual value of the system.

[0021] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0023] Figure 1 This is a schematic diagram of the design flow of the permanent magnet synchronous electric drive system integration design method of the present invention;

[0024] Figure 2 This is a schematic diagram of the four-in-one permanent magnet synchronous electric drive system of the present invention;

[0025] Figure 3 This is a torque waveform diagram based on finite element simulation results according to a preferred embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the mechanical stress field simulation process of the present invention;

[0027] Figure 5 This is a schematic diagram of the simulation results of the mechanical stress field under a preferred embodiment.

[0028] Figure 6 This is a schematic diagram of the magnetothermal bidirectional coupling simulation process of the present invention;

[0029] Figure 7 This is a schematic diagram of the temperature rise curves of various components of the electric drive system according to a preferred embodiment of the present invention. Detailed Implementation

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0031] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0032] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0033] Please see Figures 1 to 7 To address the problem of unpredictable temperatures and performance issues arising from the mutual coupling of temperature rises among components in the integrated permanent magnet synchronous electric drive system used in electric motorcycles, this invention proposes an integrated design method based on electro-magnetic-mechanical-thermal multi-physics field coupling simulation. By analyzing the magneto-thermal coupling simulation results of the integrated drive system, this method ensures that the motor and all components operate within safe temperature and mechanical strength ranges while minimizing the size of the electric drive system.

[0034] This invention provides an integrated design method for a permanent magnet synchronous electric drive system for electric motorcycles, such as... Figure 1 As shown, the main steps include the following:

[0035] S1. Based on the finite element simulation platform, design the electromagnetic scheme and establish an electromagnetic simulation model;

[0036] S2. Based on the finite element simulation platform, establish a simulation model of the mechanical stress field of the motor;

[0037] S3. Select reducers and drivers, and design DC-DC converters;

[0038] S4. Design the heat dissipation structure of the casing;

[0039] S5. Establish a simulation model of the electric drive system, including permanent magnet synchronous motor, driver, DC-DC converter, reducer, and housing, in the temperature field simulation of the finite element simulation platform.

[0040] S6. Based on the finite element simulation platform, the electromagnetic simulation model and the electric drive system simulation model are coupled in an electromagnetic-thermal bidirectional manner.

[0041] S7. Analyze the electromagnetic results and temperature rise distribution diagram obtained from the electromagnetic-thermal bidirectional coupling simulation, determine the influence of temperature on the electromagnetic performance of the motor, and output the final design scheme.

[0042] like Figure 2 As shown, the integrated design method for permanent magnet synchronous electric drive systems for electric motorcycles proposed in this invention solves the problem of unpredictable temperature rises caused by limited space during traditional integration processes. This is achieved through electro-magnetic-mechanical-thermal multi-physics coupling design during the design phase, which affects the performance of the drive system and can even lead to component damage. Using the design process of this invention, the performance of the drive system can be effectively improved, the system size reduced, and a more reliable drive solution for electric motorcycles can be provided.

[0043] Further, in step S1, an electromagnetic scheme is designed and a parametric finite element simulation model of the built-in permanent magnet synchronous motor is established based on finite element simulation software. To ensure the reliability of the electromagnetic scheme, the magnetization curve data of the permanent magnet at 100℃ is selected for simulation. When the average torque, torque ripple, output power, and other parameters in the simulation results meet the design requirements, the design scheme is saved. Specifically, the design of the electromagnetic simulation model includes the following steps: S11: Geometric structure design of the electromagnetic simulation model; S12: Parameter setting in the electromagnetic simulation model; S13: Saving the qualified simulation model. More specifically, the electromagnetic simulation model in step S1 is subjected to Maxwell electromagnetic simulation.

[0044] Furthermore, in step S2, a finite element simulation model of the mechanical stress field is established in the finite element simulation software to ensure that the local pressure of the motor rotor does not exceed the material limit; otherwise, the rotor structure in the electromagnetic simulation model should be modified by returning to step S1.

[0045] Specifically, when establishing the mechanical stress field simulation model in step S2, according to Figure 4The schematic diagram shown illustrates the process of establishing a mechanical stress simulation model. The present invention requires the following steps: S21, static structural design; S22, engineering data design; S23, geometric structural design; S24, model establishment; S25, parameter setting; S26, parameter solving; S27, output results.

[0046] See Figure 5 This is a schematic diagram of the mechanical stress field simulation results under a preferred embodiment of the present invention. If the simulation results of the rotor structure in the electromagnetic simulation model in the mechanical stress field (whether the pressure on the rotor meets the standard) are unqualified in this step, it is necessary to return to step S1 to reset the parameters.

[0047] Further, in step S3, the reducer mainly consists of transmission parts (gears or worm gears), shafts, bearings, a housing, and accessories. Its basic structure has three main parts: a combination of gears, shafts, and bearings; a housing; and reducer accessories. During the selection of the driver model, it is necessary to determine the required torque of the motor in the electromagnetic simulation model in step S1, as well as the voltage and current of the motor's operation, and then determine the corresponding driver model based on these parameters. DC-DC refers to a direct current to direct current converter, which is a device that converts electrical energy from one voltage value to another in a DC circuit. A DC-DC converter generally consists of a control chip, an inductor, diodes, transistors, and capacitors.

[0048] Furthermore, in step S4, in addition to the heat dissipation performance of the housing, the following performance characteristics can also be considered in the housing design: absorbing the forces and torques during operation; ensuring the precise relative position of the shaft and gears under various operating conditions; ensuring good heat transfer and heat radiation; isolating and attenuating noise; easy assembly and disassembly; good rigidity and strength characteristics, and light weight.

[0049] Further, in step S5, the three-dimensional simulation model of the electric drive system is subjected to Fluent thermal simulation. A three-dimensional simulation model of the electric drive system, including the permanent magnet synchronous motor, driver, DC-DC converter, reducer, and housing, is established in the temperature field simulation of the finite element simulation platform Workbench. The internal contact conditions are set, and heat sources are added based on the loss data of the driver, reducer, and DC-DC converter. This step includes: S51, geometric structure design of the three-dimensional simulation model of the electric drive system; S52, mesh design of the three-dimensional simulation model of the electric drive system; S53, parameter setting of the three-dimensional simulation model of the electric drive system; S54, parameter solving of the three-dimensional simulation model of the electric drive system; and S55, data saving of the three-dimensional simulation model of the electric drive system.

[0050] Further, in step S6, as Figure 6As shown, the Maxwell electromagnetic simulation implemented in step S1 and the Fluent thermal simulation of the three-dimensional simulation model of the electric drive system in step S5 are bidirectionally coupled. This couples the motor-related losses of the electromagnetic simulation model to the three-dimensional simulation model of the electric drive system. After calculating the temperature, the temperature is returned to the electromagnetic model, thereby updating the material loss curves corresponding to different temperatures in the electromagnetic model. Figure 7 As shown.

[0051] Furthermore, in step S7, the electromagnetic results and temperature rise distribution diagram obtained from the electromagnetic-thermal bidirectional coupling simulation in step 5 are analyzed to determine the influence of temperature on the electromagnetic performance of the motor. If excessive local temperature rise occurs, step S4 should be repeated to redesign the internal heat dissipation channels of the housing to ensure that the temperature of the motor windings, permanent magnets, and driver does not exceed 180°C.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An integrated design method for a permanent magnet synchronous electric drive system for electric motorcycles, characterized in that: The method includes the following steps: S1. Based on the finite element simulation platform, design the electromagnetic scheme and establish the electromagnetic simulation model; S2. Based on the finite element simulation platform, establish a mechanical stress field simulation model of the motor and evaluate the mechanical stress of the electromagnetic simulation model. If the evaluation is unsatisfactory, return to S1 to redesign the electromagnetic simulation model parameters. S3. Select reducers and drivers, and design DC-DC converters; S4. Design the heat dissipation structure of the casing; S5. Establish a simulation model of the electric drive system, including permanent magnet synchronous motor, driver, DC-DC converter, reducer, and housing, in the temperature field simulation of the finite element simulation platform. S6. Based on the finite element simulation platform, the electromagnetic simulation model and the electric drive system simulation model are coupled in an electromagnetic-thermal bidirectional manner. In step S6, the Maxwell electromagnetic simulation implemented by the electromagnetic simulation model in step S1 and the Fluent thermal simulation of the three-dimensional simulation model of the electric drive system in step S5 are bidirectionally coupled, so that the motor-related losses of the electromagnetic simulation model are coupled into the model of the three-dimensional simulation model of the electric drive system. After calculating the temperature, the temperature is returned to the electromagnetic model, thereby updating the material loss curves corresponding to different temperatures of the electromagnetic model. S7. Analyze the electromagnetic results and temperature rise distribution diagram obtained from the electromagnetic-thermal bidirectional coupling simulation. If the temperature rise meets expectations, output the final design scheme; if the temperature rise exceeds expectations, return to S4 to redesign the heat dissipation channel.

2. The integrated design method for a permanent magnet synchronous electric drive system for an electric motorcycle according to claim 1, characterized in that: Step S1 includes the following steps: S11: Geometric structure design of the electromagnetic simulation model; S12: Parameter setting in the electromagnetic simulation model; S13: Storing the qualified simulation model.

3. The integrated design method for a permanent magnet synchronous electric drive system for an electric motorcycle according to claim 1, characterized in that: Step S2 includes the following steps: S21, static structural design; S22, engineering data design; S23, geometric structural design; S24, model establishment; S25, parameter setting; S26, parameter solving; S27, output results.

4. The integrated design method for a permanent magnet synchronous electric drive system for an electric motorcycle according to claim 1, characterized in that: Step S5 includes the following steps: S51, geometric structure design of the three-dimensional simulation model of the electric drive system; S52, mesh design of the three-dimensional simulation model of the electric drive system; S53, parameter setting of the three-dimensional simulation model of the electric drive system; S54, parameter solving of the three-dimensional simulation model of the electric drive system; S55, data saving of the three-dimensional simulation model of the electric drive system.

Images