电动汽车用交替极轮毂电机电磁优化和高转矩精度控制策略研究

In-wheel motor can fully embody the electric drive feature of electric vehicle (EV), and has been developing rapidly in recent years. This project combines the consequent pole structure and in-wheel motor to increase the saliency according to the particularity of in-wheel motor used in EV. The corresponding integral solution with direct torque control (DTC) is proposed for improving the security and performance of EV. The researches and innovations of this project are summarized below. Electromagnetic characteristics of consequent pole in-wheel motor are studied to build accurate mathematical models, and investigate the influence rules of structure parameters to performances. Research plans of multi-objective optimization designs and derived structures are proposed for this motor. Influences of torque accuracy combining with DTC are concluded from the three different aspects of in-wheel motor, power circuit and control strategy. Change rules of torque errors with state and control variables are revealed, and the compensation methods for different influences of torque accuracy are studied. Then a high torque accuracy DTC strategy is proposed based on above research results. The successful study of this project will provide a new solution for our motors and drive systems used in EVs.

轮毂电机可充分体现电动汽车电驱动特色，近年来发展迅速。本项目针对电动汽车用轮毂电机特殊性，提出从增强凸极性角度将交替极结构应用于轮毂电机，并从提高电动汽车安全和性能的要求出发，提出一套与之相适应的高转矩精度直接转矩控制整体解决方案。本项目的研究内容和创新之处主要有：剖析交替极轮毂电机的电磁特性，建立准确的数学模型，探索结构参数对性能的影响规律，提出针对该电机的多目标优化设计和衍生结构研究方案；结合直接转矩控制，从交替极轮毂电机本体、功率电路和控制策略三个方面归纳转矩精度的影响因素，揭示转矩误差随系统状态量及控制量的变化规律，研究对应不同转矩精度影响因素的补偿方法，提出高转矩精度直接转矩控制策略。本项目的成功研究将为我国电动汽车用电机及其驱动系统提供新的解决思路。

本项目以电动汽车用交替极轮毂电机电磁优化及高转矩精度控制策略为主要研究内容，开展了理论分析、仿真和实验研究。电机本体方面，首先基于磁路法和有限元法建立了该电机数学模型，得到了磁密、电感等关键参数解析表达式，重点对电感特性和变化规律进行了研究，尤其发现了该电机电感存在单极性现象；其次在此基础上研究性能随结构参数的变化规律，得到综合优化方法，研究三种交替极轮毂电机衍生结构，在效率、转矩及功率密度等方面进一步提升。在高转矩精度控制策略方面，基于电压损失和电流损失，从功率器件、控制策略、电机本体等角度，主要研究了非线性死区的影响，提出间接补偿策略；改进直接转矩控制策略以解决零矢量的影响；建立直接转矩控制下的铁损模型，全面分析转矩精度的影响因素并进行综合补偿。.本项目所获得研究成果，已发表论文13篇，其中SCI检索3篇，EI检索8篇，授权专利2项，培养研究生5名。本项目的研究成果完善了交替极轮毂电机和高转矩精度控制理论，为车用驱动电机和控制提供了有益思路。