轮毂驱动永磁同步电机的设计与分析

发布时间：2018-09-04 15:49

【摘要】：轮毂驱动作为未来电动汽车驱动系统的主要发展方向,性能要求的核心是转矩密度大、转速范围宽以及较强的短时过载能力。本文根据技术指标要求,设计了一台70kW轮毂驱动电机,主要研究内容如下:分析比较了应用于轮毂驱动系统的电机类型及其优缺点,为满足极高的转矩密度要求,永磁同步电机是首选方案。比较各种永磁同步电机拓扑结构,结合目标应用场合进做了可行性分析。轴向磁通电机、径向磁通外转子电机理论上具有更高的转矩密度,但其特点不适用于目标场合。整数槽分布绕组结构降低了铁心有效部分尺寸,转矩密度低于分数槽集中绕组电机。单元电机槽极配合的选取主要依照转矩输出能力、电枢磁势谐波含量及齿槽转矩三个原则,选取8极9槽作为单元电机槽极配合。在确定单元电机数时,主要从转矩输出、绕组散热及转子磁极的漏磁角度考虑,32极36槽是较为合理的槽极配合。另外,作为对比方案的30极36槽电机可以使用相同的定子部分,仅需改变绕组单个线圈的连接顺序,可以认为由3个10极12槽单元电机构成。表贴式结构的弱磁扩速能力弱于内嵌式电机,同时内嵌式结构的磁阻转矩可以提高电机的转矩密度。上述结论并不适用于分数槽集中绕组电机,其输出转矩中电磁转矩占绝大部分,磁阻转矩提高转矩密度的效应计及转子上的漏磁后可以忽略不计。分数槽集中绕组电机谐波电感和漏电感显著增强了电机的弱磁扩速能力。总结电磁计算等效磁路法和有限元法的理论基础和基本流程。电磁设计基本流程为:选取三个典型工作点作为分析的着眼点,使用等效磁路法快速计算电磁性能并调整结构尺寸和电磁参量,直到性能满足设计指标,使用有限元法对电磁性能进行校核。归纳轮毂驱动永磁同步电机损耗的主要来源、计算方法及不同工作点下损耗的特点。采用集总参数热阻热路法计算电机温升,高转速工作点的损耗大于额定工作点,选取高转速工作点进行稳态热分析。将S9工作制做简化等效,计算等效S8工作制下的暂态温升。制作分数槽集中绕组轮毂驱动永磁同步电机样机,完了电机基本参数的初步测试,空载反电势测试结果与仿真结果具有良好的一致性,初步验证设计方法和相关理论的正确性,后续的负载测试试验平台正在搭建中。
[Abstract]:Hub drive is the main developing direction of electric vehicle drive system in the future. The core of performance requirement is high torque density, wide speed range and strong short time overload ability. According to the technical requirements, a 70kW hub drive motor is designed in this paper. The main research contents are as follows: the type of motor used in the hub drive system and its advantages and disadvantages are analyzed and compared, in order to meet the requirements of extremely high torque density. Permanent magnet synchronous motor is the first choice. The topology of permanent magnet synchronous motor is compared and the feasibility analysis is made in combination with the target application. Axial flux motor and radial flux outer rotor motor have higher torque density in theory, but their characteristics are not suitable for target situations. The distributed winding structure of integer slot reduces the effective part size of iron core, and the torque density is lower than that of fractional slot concentrated winding motor. According to the three principles of torque output capacity, armature magnetic potential harmonic content and tooth slot torque, 8 poles and 9 grooves are selected as the unit motor grooves. In determining the number of unit motors, it is more reasonable to consider 36 slots with 32 poles from the angle of torque output, winding heat dissipation and magnetic flux leakage of rotor pole. In addition, the 30 pole 36 slot motor can use the same stator part, and only need to change the connection sequence of the single winding coil, which can be considered as three 10 pole 12 slot unit motor. The weak magnetic expansion ability of the surface structure is weaker than that of the embedded motor, and the magnetoresistive torque of the embedded structure can increase the torque density of the motor. These conclusions are not suitable for fractional slot concentrated winding motor. The electromagnetic torque accounts for most of the output torque. The effect of increasing the torque density of the reluctance torque can be ignored after the flux leakage on the rotor is taken into account. The harmonic inductance and leakage inductance of fractional slot concentrated winding motor greatly enhance the weak magnetic expansion ability of the motor. The theoretical basis and flow chart of equivalent magnetic circuit method and finite element method for electromagnetic calculation are summarized. The basic flow of electromagnetic design is as follows: selecting three typical working points as the starting point of the analysis, using the equivalent magnetic circuit method to calculate the electromagnetic properties quickly and adjust the structure dimensions and electromagnetic parameters until the performance meets the design criteria. The finite element method is used to check the electromagnetic performance. The main source of loss of permanent magnet synchronous motor driven by wheel hub, the calculation method and the characteristics of loss at different working points are summarized. The lumped parameter thermal resistance heat path method is used to calculate the temperature rise of the motor. The loss of the high speed working point is greater than the rated working point, and the steady state thermal analysis is carried out by selecting the high rotational speed working point. The S9 operation is simplified and equivalent, and the transient temperature rise under the equivalent S8 operating system is calculated. The prototype of permanent magnet synchronous motor driven by fractional slot concentrated winding hub is made, and the basic parameters of the motor are preliminarily tested. The results of no-load back-EMF test are in good agreement with the simulation results, and the correctness of the design method and related theories is preliminarily verified. The following load test platform is being built.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM341

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