HX_D1B型电力机车牵引变流器的故障分析

介绍HXD1B型电力机车的运行情况,调查和分析牵引变流器的主要故障,论证改造方案,提出预防措施和优化思路,防止故障进一步恶化。     

CRH2型动车组网侧变流器谐波研究及电感设计

CRH2型动车组网侧变流器采用单相三电平拓扑结构.以单相二电平网侧变流器输入电压的谐波计算为基础,进而分析单相三电平网侧变流器输入电压和输入电流的谐波特性,最后研究了影响其输入电流谐波畸变率的因素,并详细介绍了电感设计原理.MATLAB仿真和试验结果与理论分析一致.     

基于小波分析的齿轮箱故障诊断

通过对齿轮箱噪声机理进行研究,建立了相应的数学模型,提出了一种基于小波变换的故障诊断方法.其基本思想是:首先利用小波变换的多分辨率特性,滤除信号的随机噪声,并将提纯后的信号分解到不同的频区;通过对各频区信号进行比较与分析,选取能量集中、包含了调制成分的部分进行复小波变换,利用多尺度小波包络谱获得信号的包络信息;最后,结合傅里叶频谱,确定齿轮箱的故障原因.研究结果表明:该方法能有效识别出齿轮箱系统中轴和齿轮的缺陷,并能锁定故障发生位置、衡量故障程度.     

三相四线制地铁辅助逆变器控制策略研究

为解决城市轨道交通辅助变流器负载不平衡问题,首先通过数学建模推导出三相四线制逆变器输出电压方程,进而以此为依据根据对称分量法得到一种简单有效的开环控制策略。为实现这种控制策略,应用三维空间矢量调制法,对其实现方法进行详细深入地探讨。通过理论分析这种控制策略,结合三维空间矢量调制法能够解决输出电压不平衡问题。用仿真对其进行验证,进一步论证了其正确性。     

基于新型测试系统的发动机匹配测试方法

基于新型测试设备多模块同步测量、触发启动等特点,根据空滤器、中冷器、消音器、散热器的性能对发动机经济性、动力性的影响,总结了整车进排气及散热系统的道路匹配测试方法,并以实例介绍了新型测试设备在此匹配测试中的应用.     

Optimal torque coordinating control of the launching with twin clutches simultaneously involved for dry dual-clutch transmission

As for the self-developed six-speed dry dual-clutch transmission (DCT), the optimal torque-coordinated control strategy between engine and dual clutches is proposed to resolve the problem of launching with twin clutches simultaneously involved based on the minimum value principle. Focusing on the sliding friction phase of the launching process, dynamics equations of dry DCT with two intermediate shafts are firstly established, and then the optimal transmitting torque variation rate and the driven plate's rotating speed of dual clutches are deduced by using the minimum value principle, in which the jerk intensity and friction work are taken as the performance indexes, and the terminal constraints of state variables are determined according to the driver's launching intention. Besides, the separating conditions of non-target gear clutch and the torque distributing relations of twin clutches are derived from the launching control targets that guarantee the approximately equal friction extent of two clutches and no power cycle. After the synchronisation of driving and driven plates of on-coming clutch, the output torque of engine is smoothly switched to the driver's demand level. Furthermore, launching the simulation model of the dry DCT vehicle is set up on the Matlab/Simulink platform. Simulation results indicate that the proposed launching control strategy not only can effectively reflect the driver's intention and extend the life span of twin clutches, but also obtain an excellent launching quality. Finally, the torque control laws of two clutches obtained through the simulation are transformed into clutch position control laws for the future realisation in the real car, and the closed-loop position controls of twin clutches in the launching process are conducted on the test bench with two sets of clutch actuator, obtaining preferable tracking effects.     

Torque coordinating robust control of shifting process for dry dual clutch transmission equipped in a hybrid car

For a hybrid car equipped with dual clutch transmission (DCT), the coordination control problems of clutches and power sources are investigated while taking full advantage of the integrated starter generator motor's fast response speed and high accuracy (speed and torque). First, a dynamic model of the shifting process is established, the vehicle acceleration is quantified according to the intentions of the driver, and the torque transmitted by clutches is calculated based on the designed disengaging principle during the torque phase. Next, a robust H_∞ controller is designed to ensure speed synchronisation despite the existence of model uncertainties, measurement noise, and engine torque lag. The engine torque lag and measurement noise are used as external disturbances to initially modify the output torque of the power source. Additionally, during the torque switch phase, the torque of the power sources is smoothly transitioned to the driver's demanded torque. Finally, the torque of the power sources is further distributed based on the optimisation of system efficiency, and the throttle opening of the engine is constrained to avoid sharp torque variations. The simulation results verify that the proposed control strategies effectively address the problem of coordinating control of clutches and power sources, establishing a foundation for the application of DCT in hybrid cars.     

基于ProE和ANSYS的变流器柜体结构分析

通过变流器结构分析的计算实例，介绍了简化有限元模型以及建立焊缝和螺栓连接结构的方法。建模过程中实现了ProE和ANSYS的仿真环境相互集成，利用软件的各自优势完成了模型简化和求解分析。分析结果表明，该变疵器柜体的强度和刚度达到了设计要求，该方法可为产品设计提供指导。     

燃料电池混合动力系统总线电压对电机转矩及效率的影响

为评价总线电压对电机转矩以及效率的影响,在动态测功机试验台架上设计相应的试验,测量总线电压在400~455 V之间变化时某三相异步感应电机的输出转矩和效率。结果表明,在电机低效率区域,电机效率受总线电压影响较大。电机输出转矩相对于目标转矩有平均0.5 s的延时,在高总线电压、高电机转速区域,电机控制器启动自保护功能,输出转矩远小于目标转矩。中国城市公交典型工况测试表明,对经济性影响最大的前80%的电机工况点主要分布于受总线电压变化影响较小的高效率区,在城市公交工况下对电机效率的粗略分析可以忽略总线电压的变化。     

利用A/T模型分析整车怠速振动性能

利用整车有限元模型计算出发动机曲轴转矩到驾驶员座椅和转向盘的加速度的传递函数,同时通过试验测量出发动机怠速时的输出转矩,因此,利用A/T模型可在汽车开发的前期较好地预测并控制整车怠速振动.最后以分析实例和试验验证了该方法在整车性能设计中的适用性和准确性.