基于TPS54340的多功能数控电源

设计并实现了一种基于DC/DC转换器的多功能数控直流电源,将12~30 V的输入波动电压变换为3.3~10 V的稳定电压输出,并通过电流串联反馈实现恒流,使该电源具备稳压源和恒流源功能;单片机作为核心实现数字化控制,通过2片12位高精度D/A转换器分别控制稳压源和恒流源的输出,并可由键盘设定输出数值,还能步进调节。该电源输出稳定、纹波小、效率高,可作为中间级DC/DC转换电源或特种电源使用,有较高的实用价值。     

激光测距仪器维修训练系统的激励电压源设计

激光测距仪器维修训练系统可满足多种型号测距仪器的测试需求,而激励电源是该系统的关键部件。对基于USB总线的程控激励电压源进行了设计,可调电压源主要由ATmega16单片机与4通道数字电位器AD8403等器件构成,USB通信电路由ATmega16与PDIUSBD12构成,并且在Windows XP系统下开发了相应的WDM驱动程序。测试结果表明该激励电压源能够满足激光测距维修训练系统要求。     

新型非最小电压应力无源无损Buck电路软开关的设计

无源无损缓冲电路可分为:最小电压应力无源无损缓冲电路和非最小电压应力无源无损缓冲电路.非最小电压应力无源无损缓冲电路中缓冲电感与电容的比值不再受到限制,能实现更宽的占空比,且具有更高的工作效率.因此本文针对非最小电压应力无源无损缓冲电路展开研究,以Buck变换器为基础,设计出了一种新型的非最小电压应力无源无损缓冲电路,经研究验证了该缓冲电路可有效降低开关损耗,且具有将缓冲过程中存储的能量回馈给电源的优势.     

一种高精度基准电压源的设计制作

对能引起电源的时间漂移及电源噪声的诸多因素进行了分析,采用了AD581集成三端器件和uA741运算放大器设计了恒温控制电路,并制作了恒温槽,设计制作高精度基准电压源。该基准源被应用于HHSV-1型高压高稳定性直流电源的基准电压,极大的提高了该直流电源的精度,使其高压高稳定性直流电源在输出电压为10000V,负载电流在2mA的工作情况下,输出电压和电流的稳定度、时漂、温漂均达到10—6量级,波纹系数达10—7。该电压源可以用作粒子加速器,质谱计,CT机等高精度医疗仪器的基准源。     

一种高性能BiCMOS带隙基准电压源设计

文章在对带隙基准基本原理与电路结构分析基础上,介绍了一种高精度、低功耗、高电源抑制比的BiCMOS带隙基准电压源电路。该电路的实现是基于0．6μm、5V的BiCMOS工艺。仿真结果表明,该基准电路稳定工作电源电压范围为1．9V～6．4V,在低频下的电源抑制比可达到-88dB,温度变化范围从-25℃至150℃时,温度系数为9．73×10^-6,输出电压误差为1．72mV。     

大功率DPSSL的高性能驱动电源的设计

根据半导体激光二极管的工作特性,设计了基于全开关拓扑的大功率DPSSL驱动电源。为了提高开关电流源输入电压的波形质量和整个电源的供电可靠性,驱动电源的前级采用单相BOOST—PFC加ZVS移相全桥电路的拓扑结构组成精密电压源,并搭建了一台3kW的实验样机验证设计方案的可行性,实验证明该驱动电源具有比较高的综合性能,能够满足材料加工工业大功率DPSSL的需要。     

甚高频共振式脉冲源放电蚀除

针对传统微细电火花脉冲电源普遍存在的放电频率低、脉宽较大、纳米级高效蚀除能力难以日益提高的问题,设计出了一种基于电路共振原理的甚高频微能脉冲源,该脉冲源可产生放电频率55 MHz、电压峰峰值220 V的开路电压波形,电压脉宽可压缩至9.1 ns。进行了不同开路电压下的放电实验,获得了各实验条件下的放电波形。实验结果证明所设计的甚高频微能脉冲源具有良好的加工工艺性能。     

一种用于D/A转换器的带隙基准电压源设计

本文设计了一种用于D/A转换器的带隙基准电压源,该电路采用中芯国际(SMIC)0.18 μm CMOS工艺设计,利用Cadence Spectre工具对其仿真,后仿结果表明,1.8V电源电压下,在-40℃～125℃温度范围内,带隙基准电压源的温度系数为4.1ppm/℃,电源抑制比(PSRR)低频时为89dB,在10 kHz时仍可以达到62.4dB.基准输出电压约为406.6mV.该带隙基准电压源能够很好的应用到高分辨DAC中.     

基于DSP的可编程交流电源研究

交直流电压源是电源实验室与科研机构必不可少的工具,针对幅值和相位连续可调交流电压源价格昂贵而直流电压源价格便宜且广泛应用于实验室中。本文研究了一种以直流电压源为输入,幅值频率可调的可编程电源。该电路由一个前级Boost电路和一个后级全桥逆变电路组成。同时,逆变电路采用倍频调制,电压电流双环控制,动态性能优越。通过制作一台以DSP为核心处理器的样机,验证了控制策略的优越性。     

一种低压高精度的CMOS带隙基准电压源

采用0.5μm CMOS工艺设计了一种高精度低压基准电压源.提出了一种结构比较新颖的基准电压源电路,该基准电压源电路具有较低的温度系数、较大的温度范围和较高的电源抑制比.此外,还增加了提高电源抑制比电路、启动电路,以保证电路工作点正常、性能优良,并使电路的静态功耗较小.Spice仿真结果表明低频时电源抑制比可达70dB;在-40～120℃范围内,输出变化仅为0.004V,温度系数可达25×10-6V/℃;静态功耗小,在电源电压Vdd=3.3V时,总功耗约为0.025mW.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.