【作者】 王旭；

【导师】 周俊；

【作者基本信息】 南京农业大学 ， 农业机械化工程， 2022， 硕士

【摘要】 随着石油资源日渐短缺,人们对环境污染的问题越来越关注,电动拖拉机因其绿色环保、节能高效成为国内外学者的研究热点。拖拉机作业工况复杂,单电机驱动的动力系统很难满足多样化的作业需求。本文针对双电机驱动拖拉机,制定了双电机耦合系统结构方案并对传动系统关键部件进行参数匹配,以动力性和经济性为目标对传动系统参数进行优化,对优化前后的性能进行了仿真对比。本文主要研究内容如下:(1)根据拖拉机作业工况多样化的特点,设计了一种双电机动力耦合系统结构方案,可以实现包括转矩耦合和转速耦合在内的五种驱动模式。介绍了动力耦合系统方案的基本原理和不同模式的切换过程。根据耦合结构的特点,对每种驱动模式下的电机输入输出转矩转速关系进行分析,绘制功率流向。提出适应于双电机驱动系统的模式选择和动力分配策略,对驱动模式初步筛选后,计算每个可行的驱动模式下的最小能耗,确定处于最小能耗时的转矩/转速信息。(2)根据动力性要求对电动拖拉机的电机和动力电池组进行选型和参数匹配。以动力性指标对传动系统中行星齿轮特征参数和减速箱速比进行了匹配,为下一步的参数优化提供基础。(3)分析传统遗传算法(GA)的优缺点,对GA中选择算子、变异算子、交叉算子进行改进。基于改进后的遗传算法对传动系统参数进行优化,以能量消耗和驱动系统利用率为目标函数进行优化。采用逆向建模的方法对电机、电池、整车、作业工况进行了建模。作业工况包括运输、犁耕两种拖拉机具有代表性的作业工况,其中运输作业选定低速EUDC工况作为参考工况并进行修改,犁耕作业以田间实际采集的数据建立作业工况,作业工况包括作业速度和牵引阻力。对优化前后的系统结构进行仿真并对比动力性能和经济性能,证明优化后的拖拉机能够在满足动力性需求的基础上有更好的经济性能。对优化后的动力系统在Solid Works中建模,并导入ADAMS中进行动力学仿真分析,证明机构的合理性。(4)基于d SPACE和MATLAB/Simulink搭建了一种新型的快速原型拖拉机试验平台,该试验平台具有完备的测控系统,对试验平台主要部件的特性参数进行了测试,获取了电机特性曲线、电机效率MAP图和动力电池组开端电压与SOC的变化关系图。搭建了硬件在环仿真系统,进行了双电机独立驱动模式和转速耦合模式的硬件在环仿真,试验结果表明试验平台可以较好的模拟多种作业工况,各部件响应迅速,控制效果良好。更多还原

【Abstract】 With the increasing shortage of oil resources,people pay more and more attention to the problem of environmental pollution.Electric tractors have become a research hotspot of scholars at home and abroad due to their green environmental protection,energy saving and high efficiency.Tractor operating conditions are complex,single motor driven power system is difficult to meet the diverse operating requirements.In this paper,the structure scheme of the dual motor coupling system is formulated for the dual motor drive tractor,and the parameters of the key components of the transmission system are matched.The transmission system parameters are optimized with the goal of power and economy.The performance before and after optimization is simulated and compared.The main research contents of this paper are as follows :(1)According to the diversified working conditions of tractors,a dual-motor dynamic coupling system structure scheme is designed,which can realize five driving modes including torque coupling and speed coupling.The basic principle of dynamic coupling system scheme and the switching process of different modes are introduced.According to the characteristics of the coupling structure,the relationship between input and output torque and speed of the motor under each driving mode is analyzed,and the power flow direction is drawn.The mode selection and power distribution strategy suitable for the dual-motor drive system are proposed.After the preliminary screening of the drive mode,the minimum energy consumption under each feasible drive mode is calculated to determine the torque / speed information at the minimum energy consumption.(2)According to the dynamic requirements of electric tractor motor and power battery group selection and parameter matching.The planetary gear characteristic parameters and the gearbox speed ratio in the transmission system are matched by the dynamic performance index,which provides the basis for the next parameter optimization.(3)The advantages and disadvantages of traditional genetic algorithm(GA)are analyzed,and the selection operator,mutation operator and crossover operator in GA are improved.The transmission system parameters are optimized based on the improved genetic algorithm,and the energy consumption and the utilization rate of the drive system are optimized as the objective functions.The motor,battery,vehicle and working condition are modeled by reverse modeling.The working conditions include transportation and ploughing,which are two representative working conditions of tractors.The transportation operation selects the low speed EUDC working condition as the reference condition and modifies it.The ploughing operation establishes the working condition based on the data collected in the field,and the working condition includes the working speed and the traction resistance.The simulation of the system structure before and after optimization and the comparison of dynamic performance and economic performance prove that the optimized tractor can have better economic performance on the basis of meeting the power demand.The optimized dynamic system is modeled in Solid Works,and imported into ADAMS for dynamic simulation analysis to prove the rationality of the mechanism.(4)A new type of rapid prototyping tractor test platform was built based on d SPACE and MATLAB / Simulink.The test platform has a complete measurement and control system.The characteristic parameters of the main components of the test platform were tested,and the motor characteristic curve,motor efficiency MAP and the relationship between the start voltage of power battery pack and SOC were obtained.The hardware-in-the-loop simulation system is built,and the hardware-in-the-loop simulation of the independent driving mode and the speed coupling mode of the dual motor is carried out.The experimental results show that the experimental platform can simulate a variety of better.更多还原