电动汽车DC／DC变换器主电路EMI测试与分析

主要针对电动汽车用直流／直流（DC／DC）变换器主电路的EMI进行测试和分析,得到DC／DC变换器主电路的EMI特征,为设计有效的EMI抑制措施及制订电动汽车零部件电磁兼容标准奠定基础。     

电动汽车DC／DC变换器控制系统EMI测试与分析

针对电动汽车用直流／直流（DC／DC）变换器控制系统的EMI进行测试和分析,得到DC／DC变换器控制系统的EMI特征,为设计有效的EMI抑制措施提供依据,同时为电动汽车零部件电磁兼容标准的制定奠定基础。     

基于saber的开关电源EMI仿真分析

为在开关电源设计中降低EMI电磁干扰,提高开关电源的电磁兼容性,在开关电源设计最初阶段对系统进行EMI电磁干扰仿真分析十分重要。针对开关电源DC/DC变换器工作时产生的强烈的EMI电磁干扰,分析了非隔离式buck型DC/DC变换器的工作原理,研究了该变换器产生EMI的电磁干扰源,提出了DC/DC变换器电磁干扰抑制措施,并应用saber软件建模仿真,对抑制结果进行对比验证。结果证明本文提出的抑制方法可有效抑制开关电源EMI电磁干扰。     

燃料电池Buck变换器的动态演化控制仿真

针对燃料电池DC/DC变换器的工作优化问题,对DC/DC变换器的控制方法和输出响应特性进行了研究,提出了一种新型控制方法—动态演化控制,并将其应用于具体设计的燃料电池两相交错并联同步Buck变换器中,论述了该变换器的动态演化控制设计步骤,通过对变换器的特征方程以及动态演化路径进行分析,建立了控制占空比与动态演化方程之间的关系,进而实现对该变换器进行动态演化控制.利用Matlab-Simulink仿真平台对两相交错并联同步Buck变换器仿真模型分别在动态演化控制和传统PI控制下的负载突变输出性能进行了仿真测试.仿真研究结果表明,动态演化控制具备快速的动态响应能力和良好的抗干扰性能,比传统PI控制更为优越.     

基于单片机的双输入DC/AC变换器

提出了一种基于BUCK电路的DC/AC变换器结构,并介绍了其工作原理。变换器采用双BUCK电路为主电路,双电源供电,dsPIC30F4011单片机为控制器。应用PSIM软件对其进行仿真,列出了仿真参数,给出了负载电压,以及调制给定电压和变换器输出电压的仿真结果。同时构建了相应的实验电路,给出了主要的技术参数,测取了多个电压的相关波形。实验结果表明基于BUCK电路的DC/AC变换器可以实现工频逆变输出。     

PSpice对Buck变换器参数的仿真研究

DC/DC(Buck)变换器参数的变化对电路启动时的暂态工作过程和电路稳定后的稳态工作过程影响较大.PSplce是一款功能强大的电路仿真软件,可对各种模拟和数字电路进行仿真.本文通过建立数学模型、利用PSpice软件对DC/DC变换器电路的暂态和稳态过程及性能进行仿真研究.仿真结果表明,暂态阶段电流和功率较大,输出电压的大小受到电路L1和RL等器件参数的控制.为开发Buck变换器提供了理论依据.     

用户多电源供电储能系统蓄电池充放电控制研究

为了提升蓄电池充放电控制的准确性,对用户多电源供电储能系统蓄电池充放电控制进行研究。通过设计双向AC/DC变换器实现蓄电池充放电控制,以双向AC/DC变换器一般数学模型为基础,加入同步旋转坐标系构建双向AC/DC变换器dq模型,提升蓄电池充放电控制的准确性;并网运行时,双向AC/DC变换器利用PQ控制策略,完成蓄电池充放电过程中功率平衡控制;离网运行时,双向AC/DC变换器利用V/f控制策略,完成蓄电池充放电过程中电压与频率的平衡控制。实验结果表明,所研究蓄电池充放电控制策略能够有效控制蓄电池充放电,提升蓄电池充放电过程中功率平衡控制的准确性。     

2533型数字式交直流混合波形功率测量仪

2533型(DC/AC型)数字式功率仪,是继1986年3月公布的2533(AC型)之后,研制成功的第二代功率测量仪。由于在AC型已经具备的测量电压、电流、有效功率、视在功率、功率因数、平均电流及功率和等功能的基础上,追加了可供用户选择的频率测量、积算以及藉助GP-IB或RS-232的远程控制功能,从而使2533(DC/AC型)能够进行AC型无法完成的交、直流混合波形及半波和金波整流波形的功率测量。与AC型相同,DC/AC型共有三种型式,可供“单相”、“三相三线制“和”三相四线制”使用。 DC/AC型功率测量仪的主要用途是进行由变换器驱动的旋转式电器设备、电机、变压     

基于共模扼流圈高频模型的Boost PFC的EMI滤波器设计

针对Boost PFC变换器存在的传导电磁干扰问题,对Boost PFC变换器在加入平衡电容前后的共模、差模干扰传导路径进行了分析,进而对混合传导电磁干扰的成因及抑制方法进行了研究。对共模扼流圈的非理想因素及现有高频模型的局限性进行了归纳,综合考虑了磁芯材料频率特性及绕组寄生电容的影响,建立了一种改进的Foster网络串联模型,并提出了一种基于共模扼流圈阻抗特性优化的EMI滤波器设计方案,利用一套1.25 k W的Boost PFC变换器样机进行了对比实验验证。研究结果表明:将所设计的EMI滤波器加入电路后,待测装置能顺利通过传导干扰测试。     

一种可并网光伏发电逆变器设计

文中介绍了一种可并网式光伏发电逆变器设计方案,给出了光伏发电系统的组成结构,重点对逆变器的核心前级DC/DC升压器与后级DC/AC变换器的拓扑结构和电路相关参数设计进行了详细分析说明。按照此方法设计了电路,并给出了输出电压波形的仿真结果与相关测量数据。实验结果表明:该系统输出电压技术指标满足并入市电电网的要求,达到了并网的目的。     

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。     

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.     

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。     

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.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.     

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...     

OPTIMIZATION METHOD ON IMPELLER MERIDIONAL CONTOUR AND 3D BLADE

An optimization method for 3D blade and meridional contour of centrifugal or mixed-flow impeller based on the 3D viscous computational fluid dynamics (CFD) analysis is proposed. The blade is indirectly parameterized using the angular momentum and calculated by inverse design method. The design variables are separated into two categories: the meridional contour design variables and the blade design variables. Firstly, only the blade is optimized using genetic algorithm with the meridional contour remained constant. The artificial neural network (ANN) techniques with the training sample data schemed according to design of experiment theory are adopted to construct the response relation between the blade design variables and the impeller performance. Then, based on the ANN approximated relation between the meridional contour design variables and impeller performance, the meridional contour is optimized. Fewer design variables and less calculation effort is required in this method that may be widely used in the optimization of three-dimension impellers. An optimized impeller in a mixed-flow pump, where the head and the efficiency are enhanced by 12.9% and 4.5% respectively, confirms the validity of this newly proposed method.