Dynamic response of functional virtual prototyping of motorcycle under combined excitations

This paper developed 3D product models of motorcycle and engine by UGNX as well as virtual prototyping by ADAMS program with road roughness generated by MATLAB. Under the straight-line running condition, the dynamic responses of motorcycle multibody system to both road and engine excitations were compared with those to only road excitation in terms of vertical acceleration response, amplitude frequency response and power spectral density. The comparisons of simulation data showed that the response due to flat road excitation was around 20 Hz, while that to the combined excitations was in a wide frequency band, of which the major components focused on 10 Hz, 15 Hz, 35 Hz ,70 Hz, 100 Hz and even higher frequencies, reflecting the characteristics of engine excitation based on its unbalanced inertia force and torque. It is concluded that the high fidelity virtual prototyping can simulate the dynamics of motorcycle product well in investigating the vibration and ride comfort performance.     

上海电校电力仿真机发电厂励磁系统的建模

介绍了对上海电校电力仿真机发电厂励磁系统、应用STAR－90支撑系统及采用模块化建模技术进行发电厂励磁调节器的建模方法。调试运行结果表明,使用该技术建立的仿真系统,能够准确及时反映实际系统的运行特性及规律。     

发电机组实时监测和诊断专家系统的开发和应用研究

针对发电机故障诊断的特点,结合实时数据采集和专家系统的开发思想,建立了具有针对性的实时监控和故障诊断专家系统的框架,分析了三层子系统的分解模式和实现,系统的知识表示、诊断和学习过程的通用方法.     

汽轮发电机主厂房土建施工重点的控制方法

对汽轮发电机主厂房土建施工中的汽轮发电机基础施工、锅炉基础施工、吊车梁施工、钢煤仓制作与安装、轴线控制与埋件安装中的重点与难点进行了分析,提出了相应的控制和施工方法.     

高压激励8极板电容层析成像系统研究

电容层析成像是检测封闭空间内部不同介电常数物质分布的有效技术手段。常见的电容层析成像系统被测对象直径一般为10 cm左右,电容检测电路的工作电压一般不超过20 Vpp。当ECT系统应用在粮仓等大尺寸的对象上时,需要提高激励电压以较高的灵敏度和分辨率,从而获得良好重建图像。文章介绍了高压激励电容层析成像系统的结构,给出了内置8极板电容传感器阵列的详细参数,并介绍了几种典型的分布模型的重建图像和误差数据。实验表明：本文所设计的高压电容层析成像系统具有良好的图像重建能力。     

矸石电厂2#发电机改换励磁系统简述

近几年来,由于新技术、新工艺和新器件的涌现和使用,使得发电机的励磁方式得到了不断的发展和完善,大幅度地提高了电厂的工作效率。本文就矸石电厂2#发电机改造前后的励磁系统做一简单阐述。     

杨凌水电站励磁调节装置的改造浅析

微机励磁调节已经开始全面应用于现代化水电站,并获得进一步的研究和发展。杨凌水电站的励磁装置经过改造,采用微机励磁调节装置,性能已经远远优于未改造之前的励磁调节装置。本文主要从原理和结构上分析了励磁调节装置的缺点和不足及微机励磁调节装置在性能上的优化和使用上的便捷。     

水平和竖向地震激励下大型储液罐响应分析

基于ANSYS软件建立了100km3锚固型大型储液罐模型,并对此进行了水平和竖向地震激励下的地震响应分析,地震波为EL-CENTRO波。计算结果表明,锚固型大型储液罐内液体的晃动、应力和应变在水平地震激励下比竖向地震激励下大很多,这说明水平地震激励是影响储液罐力学性状的主要因素之一。储液罐的应力和应变峰值发生在罐的中下部,而罐口变形较大。     

论音乐作用于人体的激励机制

音乐对人体产生着及其奇特的作用，十分有利于人的身心健康。该文根据祖国传统医学和现代医学理论并结合心理学等多学科知识，从边缘科学角度，认为音乐主要作用于人的大脑皮层，调节人的神经系统的兴奋与抑制的平衡，再通过人的神经系统作用于人的其他系统，并就音乐作用与人体身心健康的激励机制进行探究分析，同时就如何应用音乐疗法造福人类提出了自己的主张。     

福建丰源水电厂励磁系统参数辨识探讨

为电网分析、计算提供准确的BPA标准发电机励磁系统模型参数,文章在Matlab环境下建立发电机励磁系统标准模型,以现场试验数据为基础,对模型参数进行辨识并确定其模型参数。随后,通过BPA软件进行空载阶跃响应校核以及负载阶跃响应校核,结果与现场实测波形基本一致,从而认为辨识得到的BPA标准模型参数是正确和有效的。     

基于LPC2103的同步发电机端电压稳定控制系统

提出基于LPC2103的同步发电机励磁控制系统设计。介绍了系统的硬件设计方案;软件设计,包括系统的的主程序流程图、频率测量、模糊PID控制以及其实现的基本方法。测试结果表明,利用ARM微控制器可使编程操作简单,调节速度快,主要性能指标符合要求。     

Study on inverter fault-tolerant operation of PMSM DTC

This paper presents an investigation of inverter fault-tolerant operation for a permanent magnet synchronous motor （PMSM） direct torque control （DTC） system under various inverter faults. The performance of a faulty standard 6-switch inverter driven PMSM DTC system is analyzed. To avoid the loss or even disaster caused by the inverter faults, a topology-modified inverter with fault-tolerant capability is introduced, which is reconfigured as a 3-phase 4-switch inverter. The modeling of the 4-switch inverter is then analyzed and a novel DTC strategy with a unique nonlinear perpendicular flux observer and feedback compensation scheme is proposed for obtaining a continuous, disturbance-flee drive system. The simulation and experimental results demonstrate that the proposed inverter fault-tolerant PMSM DTC system is able to operate stably and continuously with acceptable static and pretty good dynamic performance.     

Direct driven wind energy conversion system based on hybrid excitation synchronous machine

A novel direct-drive type wind power generation system based on hybrid excitation synchronous machine (HESM) is introduced in this paper. The generator is connected to an uncontrollable rectifier, and a fully controlled voltage-source inverter is used to connect the system to utility grid. An intermediate DC bus exists between the rectifier and inverter. A new control strategy is proposed which achieves the maximum power point tracking (MPPT) with the control of excitation current of HESM and stabilizes the DC link voltage with the control of inverter output current simultaneously. Specially-designed buck circuit is used to control the excitation current of HESM, and grid voltage-oriented vector control strategy is employed to realize the decoupling of the inverter output power. Simulation results and experiment in 3 kW lab prototype show an excellent static and dynamic performance of the proposed system.     

NJ2型机车接地故障的GDA检测方法探究

针对NJ2型机车的接地故障,介绍了故障检测设备GDA的电路及接线,探讨了辅助电路和牵引系统的接地故障检测电路,分析了蓄电池充电电路、辅助电动机、励磁电路和牵引系统的故障类型及GDA检测方法。     

Duffing系统的非反馈法混沌控制

对Duffing系统混沌解进行非周期外激励控制、周期外激励控制和外激励相位控制，对它们进行数值仿真和理论分析。非周期外激励控制的控制项十分简单，容易实现，但难以做到微小控制而不改变系统本身。周期外激励控制采用微小周期控制项，但难以有好的控制效果。外激励相位控制采用微小信号控制并使控制信号与系统的不稳定周期轨道达到最佳相位匹配，获得最佳控制效果。     

完善国有外贸企业激励机制的对策研究

本文探讨了完善国有外贸企业激励机制的方法和途经。认为明确和调整产权结构是建立和完善外贸企业激励机制的前提 ,改善分配制度是完善外贸企业激励机制的基础 ,强化约束机制是完善外贸企业激励机制的关键     

基于国有企业经营者视角的激励机制解释

一方面,由我国市场发育的特点决定,国有企业经营者承担的职能更加复杂,对企业的生存发展也更为重要;另一方面,由多层委托-代理关系决定,国有企业的代理成本过高,国有企业经营者对企业所有者利益损害的可能性较大.尽快建立、完善对企业经营者的激励机制是国有企业及其所有者的现实选择.科学的经营者激励机制应体现两个特征：（1）按劳取酬;（2）有效竞争.     

国有企业激励机制失灵的原因及重建

文章从国企体制、人们观念和激励形式分析了国企激励机制失灵的原因，并从转变思想认识、长期和短期激励相结合、物质和非物质激励相结合以及建立科学的考核体制等几个方面对国企激励机制的建设进行了一些探索。     

乌金峡水电站励磁系统分析研究

分析了乌金峡水电站励磁系统的硬件结构和功能,提出了励磁系统的试验程序、方法及相关标准,详细分析了励磁系统运行过程中出现的问题及解决办法,并对今后的检修维护提出了建议。     

A METHOD OF ON-LINE MEASUREMENT FOR THE FREQUENCY RESPONSE AND IMPULSE RESPONSE FUNCTIONS OF MULTIVARIATE SYSTEM

In this paper,a method of multipoint pseudorandom combined excita-tion with the orthogonal reciprocal repeated sequences(ORRS)is presented on thebackground of the on-line identification of multivariate system.The capacity of therestraint to the identification error caused by the non-random D.C.drift of the mul-ti-input excitation with the ORRS in the multivariate system is also discussed.Thevalidity of the method described in this paper is proved by the modelling tests of themulti-plate rotor system.