【作者】 王勇；

【导师】 孙冬野；

【作者基本信息】 重庆大学 ， 机械工程， 2018， 博士

【摘要】 纯电动汽车以电动机为动力装置,以蓄电池为能量储存装置,与混合动力汽车相比,具有结构简单、噪音小和零排放等优点。纯电动汽车凭借广阔的产业化前景,在全球各地受到了广泛关注与高度重视。如何提升纯电动汽车的续驶里程和综合性能现已成为电动汽车技术的主要研究方向,而提高续驶里程除了依赖于蓄电池技术外,还受到诸多因素的影响,包括动力总成及其控制技术、高效的传动系统及功能全面的能量管理控制方法。本文针对纯电动汽车双驱动力传动系统的新构型开展研究工作,其具有的两个动力源能够依据不同工况在多个工作模式之间实现切换,可显著提升纯电动汽车续驶里程,大幅拓宽合成动力源驱动高效率区域范围。此外,该系统具备ECVT(Electric Continuously Variable Transmission)的功能,利用扩大变速系统的速比变化范围来有效提升纯电动汽车续驶里程,同时在保障行车安全性的前提下,让汽车制动能量回收更为高效,实现续驶里程的进一步提高。本文具体研究内容如下:(1)针对纯电动汽车双驱动力传动系统新构型的工作特性展开分析,并详述其各种工作模式,通过杠杆原理构建系统动力学模型,为后续匹配设计与控制方法研究提供基础。同时基于对电动汽车能耗与驱动电机工作特性的分析,对纯电动汽车双驱动力传动系统新构型的节能潜力及节能机理展开探讨。(2)探究整车性能和驱动电机系统功率之间的关系,构建峰值功率与最高车速、加速能力、爬坡能力的关系模型;对多种循环工况的需求功率分布情况进行分析,得出负荷功率概率,作为初步匹配设计的依据;基于上述工作进行动力传动系统参数初步匹配,利用构建的仿真平台对初步匹配参数的合理性进行验证;为提升整车性能,创建包含动力性与经济性指标的多目标优化函数,运用遗传算法对动力传动系统参数进行优化设计。(3)综合考虑动力传动系统各部件效率及各工作模式下动力传动系统效率对整车效率的影响,在保证整车动力性的前提下,以提高整车续驶里程为目标,制定基于逻辑门限的实时效率最优控制策略;另外考虑到驾驶意图对整车性能的影响,对驾驶意图进行科学分类,制定基于驾驶意图的实时优化控制策略,并对此展开仿真对比分析。(4)在分析关键部件动态特性的基础上,构建电机动态仿真模型、液压系统执行机构模型和湿式离合器/制动器动力学模型,为模式切换动态过程研究奠定基础;结合双驱动力传动系统各部件的工作特性和各工作模式特点,制定科学合理的模式切换控制流程;针对转速调节过程,提出电机、离合器/制动器的转矩协调控制方法;利用MATLAB/Simulink平台对各工作模式之间的模式切换过程完成仿真分析。(5)完成基础数据试验,为开展后续研究提供数据支撑,并对纯电动汽车双驱动力传动系统试验样机和试验台架进行设计加工,运用Matlab/Simulink及dSPACE平台对双驱动力传动系统控制程序及试验台架测控软件进行开发,完成基于dSPACE的纯电动汽车双驱动力传动系统台架试验系统开发;运用开发的台架试验系统完成纯电动汽车双驱动力传动系统的功能性试验。更多还原

【Abstract】 Compared with hybrid electric vehicles,pure electric vehicles employ electric motors as power devices and accumulator as energy storage devices,with the advantages of simple structure,low noise and zero emission.Pure electric vehicles have attracted wide concern and high attention all over the world by right of their broad industrialization prospects.It has become the major research direction to resolve the problem of how to improve the driving range and comprehensive performance of pure electric vehicles.However,besides battery technology,the improvement of driving range is also affected by many factors,including power assembly and its control technology,efficient transmission system and full-featured energy management control strategy.This thesis proposes a new dual drive powertrain for pure electric vehicles,which has two power sources that can switch among several working modes in accordance with different working conditions,and thus significantly improve the driving range of pure electric vehicles and greatly expand the efficiency range driven by synthetic power sources.In addition,the system has the function of ECVT(Electric Continuous Variable Transmission),which enlarges the speed ratio range of the transmission system to effectively improve the driving range of pure electric vehicles.Meanwhile,under the premise of driving safety,the braking energy recovery of the vehicle becomes more efficient and the driving range is further improved.The details of this study are listed as follows.(1)This paper aims to analyze the working characteristics of the dual drive powertrain of pure electric vehicles mentioned above,describe its various working modes,and provide a basis for the subsequent matching design and control method research through the system dynamics model constructed by lever principle.Furthermore,based on the analysis of energy consumption of electric vehicles and the working characteristics of driving motors,the energy-saving potential and mechanism of the new dual-drive transmission system configuration of pure electric vehicles are discussed.(2)The relationship between vehicle performance and the power of driving motor system is explored,and the relationship model between peak power and maximum speed,acceleration and climbing capability is constructed.In addition,this study will obtain the load power probability by analyzing the demand power distribution under various cyclic conditions,which is utilized as the basis of preliminary matching design.Based on the above work,the preliminary matching of power transmission system parameters is carried out,and the rationality of the preliminary matching parameters is verified by the built simulation platform.In order to improve the performance of the vehicle,a multi-objective optimization function including dynamic and economic indexes is created,and the genetic algorithm is used to optimize the power transmission system parameters.(3)This study comprehensively considers the efficiency of each component of the power transmission system and the influence of the efficiency on the overall vehicle efficiency under various working modes.A real-time optimal control strategy which is based on the logic threshold is formulated to improve the diving range under the premise of guaranteeing the vehicle’s dynamic performance.Besides,considering the effect of driving intention on the vehicle performance,the driving intention is classified scientifically,and the real-time optimal control strategy based on driving intention is formulated,and then the simulation comparison analysis is carried out.(4)Based on the analysis of the dynamic characteristics of the key components,the dynamic simulation model of the motor,the actuator model of the hydraulic system and the dynamic model of the wet clutch/brake are constructed to lay the foundation for the study of the dynamic process of mode switching.Combining the working characteristics of each component of the dual drive powertrain and the characteristics of each working mode,a scientific and reasonable mode switching control flow is formulated.In addition,a torque coordinated control method of motor,clutch and brake is proposed for the process of speed regulation.Moreover,the MATLAB/Simulink platform is employed so as to complete the simulation analysis of the mode switching process among the various working modes.(5)Then the basic data test is completed to provide a basis for the follow-up research.Furthermore,the prototype and test bench of the dual-drive transmission system of pure electric vehicles are developed and designed.The control program and test bench software of the dual-drive transmission system are developed through the MATLAB/Simulink and dSPACE platform.What’s more,the bench test system of dual-drive transmission system of pure electric vehicles is developed on the basis of dSPACE,which is then utilized to complete the functional test of the dual-drive transmission system of pure electric vehicles.更多还原