摘要
目的:混合动力传动系统作为一种节能减排技术方案,可有效改善传统液压挖掘机的油耗和尾气排放。混合动力挖掘机中关键部件的研制,尤其是动力电机的研制,一直是阻碍混合动力系统应用和推广的难点。本文针对混合动力挖掘机实际工况和要求,对混合动力挖掘机的动力电机进行优化设计。创新点:根据液压挖掘机实际工况特点,总结归纳了混合动力挖掘机动力电机的性能要求,提出一种动力电机结构;根据动力电机性能和工作环境要求,为提高电机设计效率和精度,提出一套采用模型法与有限元法相结合的电机设计方法。方法:对传统液压挖掘机工况及实际载荷谱进行分析,总结归纳动力电机的性能要求。动力电机采用内置切向式和变气隙相结合的结构方案作为电机转子结构。电机的设计以安装尺寸为约束条件,以电机具有高效率、高响应及低转矩脉动等性能为设计目标,对电机定、转子结构进行优化设计。首先,建立电机定子参数化模型,确定电机定子尺寸和磁感应强度的分布关系;以电机安装尺寸极限作为边界条件,以电机额定工况下损耗最低为目标函数,对模型采用粒子群算法进行优化获取定子参数及磁感应强度分布。然后,以气隙磁感应强度的波形畸变最小为目标,利用有限元法对电机变气隙转子的离心率及永磁体尺寸进行优化设计,同时保证所获得的电机磁感应强度与定子的理论设计目标值一致。分别对电枢反应、永磁体最大去磁进行计算和校核。研制了动力电机样机并进行性能和参数测试。结论:所设计动力电机样机具有齿槽转矩小和工作效率较高的特点。样机的试验参数测量值与理论设计值吻合度较高,验证了所提电机设计及优化方法的有效性。
A hybrid power transmission system (HPTS) is a promising way to save energy in a hydraulic excavator and the electric machine is one of the key components of the system. In this paper, a design process for permanent-magnet synchronous machines (PMSMs) in a hybrid hydraulic excavator (HHE) is presented based on the analysis of the working conditions and requirements of an HHE. A parameterized design approach, which combines the analytical model and the 2D finite element method (FEM), is applied to the electric machine to improve the design efficiency and accuracy. The analytical model is employed to optimize the electric machine efficiency and obtain the statordimension and flux density distribution. The rotor is designed with the FEM to satisfy the flux requirements obtained in stator design. The rotor configuration of the PMSM employs an interior magnet structure, thus resulting in some inverse saliency, which allows for much higher values in magnetic flux density. To reduce the rotor leakage, a disconnected type silicon steel block structure is adopted. To improve the air gap flux density distribution, the trapezoid permanent magnet (PM) and centrifugal rotor structure are applied to PMSM. Demagnetization and armature reactions are also taken into consideration and calculated by the FEM. A prototype of the newly designed electric machine has been fabri- cated and tested on the experimental platform. The analytical design results are validated by measurements.
基金
Project supported by the National Natural Science Foundation of China(Nos.51475414 and 51221004)
关键词
混合动力液压挖掘机
模型法
有限元法
永磁同步电机
Analysis, Design, Hybrid hydraulic excavator (HHE), Finite element method (FEM), Interior permanent-magnet(PM) motor, PM synchronous machine (PMSM)