车用内置式永磁同步电机转子热–机械应力耦合分析

Thermal Mechanical Stress Coupling Analysis of Rotor in Built-In Permanent Magnet Synchronous Motor for Vehicles

摘要: 永磁同步电机因具有高效率、高功率密度、低噪音和高精度控制等优点，被广泛应用于新能源汽车等领域。随着高速电机技术的不断发展，对于更高转速扭矩的要求进一步加剧转子失效的风险，表现为转子磁轭单片突出、磁桥断裂等现象。电机转子作为电驱系统的核心部件，对其进行热–机械耦合应力分析以及失效主导载荷的确定，对于车用驱动电机的设计有指导意义。通过建立永磁同步电机转子模型，进行转子的温度场仿真、应力场仿真分析得出了转子的热–机械耦合应力，在本文电机动态工况最高转速下，转子的机械应力为121.35 Mpa，热–机械耦合应力为142.42 Mpa，其中机械应力占比为85.21%，明确了电机转子失效的主要载荷，也为以后的高转速、大功率车用驱动电机转子的设计奠定了基础。

Abstract: Permanent magnet synchronous motors are widely used in fields such as new energy vehicles due to their advantages of high efficiency, high power density, low noise, and high-precision control. With the continuous development of high-speed motor technology, the demand for higher speed torque further exacerbates the risk of rotor failure, manifested as phenomena such as rotor yoke single piece protrusion and magnetic bridge fracture. As the core component of the electric drive system, the thermal mechanical coupling stress analysis of the motor rotor and the determination of the dominant failure load have guiding significance for the design of automotive drive motors. By establishing a rotor model of a permanent magnet synchronous motor and conducting temperature field simulation and stress field simulation analysis, the thermal mechanical coupling stress of the rotor was obtained. At the highest dynamic operating speed of the motor in this paper, the mechanical stress of the rotor was 121.35 MPa, and the thermal mechanical coupling stress was 142.42 MPa, of which mechanical stress accounted for 85.21%. The main load causing the failure of the motor rotor was identified, laying the foundation for the design of high-speed and high-power vehicle drive motor rotors in the future.