新能源汽车电池大模组Busbar激光焊接工艺探究

针对新能源汽车电池大模组的生产需求,对Busbar及电芯极耳进行激光焊接试验,改变激光功率、焊接速度等工艺参数,比较搅拌激光焊和无搅拌激光焊接工艺,并考察了焊缝的组织形貌、孔隙率、抗剪强度等性能。研究发现,Busbar激光焊接优化工艺为中心功率3400 W,外环功率1800 W,焊接速度25 mm/s,离焦量+1 mm,焊接接头成形良好。比较搅拌激光焊接和无搅拌激光焊接工艺,Busbar激光搅拌焊接接头最大剪切强度为164 MPa,无搅拌激光焊接接头最大剪切强度为152 MPa,从而证明激光搅拌焊接工艺能够显著优化Busbar接头的焊接质量。

Numerical simulation of busbar configuration in large aluminum electrolysis cell

Various busbar configurations were built and modeled by the custom code based on the commercial package ANSYS for the 500 kA aluminum electrolysis cell.The configuration parameters,such as side riser entry ratio,number of cathode bars connected to each riser,vertical location of side cathode busbar and short side cathode busbar,distance between rows of cells in potline,the number of neighboring cells,ratio of compensation busbar carried passing under cell and its horizontal location under cell along with large magnetohydrodynamic(MHD) computation based on the custom evaluation function were simulated and discussed.The results show that a cell with riser entry ratio of 11:9:8:9:11 and cathode busbar located at the level of aluminum solution,50% upstream cathode current passing under cell for magnetic field compensation,the distance between rows of 50 m is more stable.

Thermal Dissipation Modelling and Design of ITER PF Converter Alternating Current Busbar

Because the larger metallic surrounds are heated by the eddy current, which is generated by the AC current flowing through the AC busbar in the International Thermonuclear ExperimentM Reactor （ITER） poloidal field （PF） converter system, shielding of the AC busbar is required to decrease the temperature rise of the surrounds to satisfy the design requirement. Three special types of AC busbar with natural cooling, air cooling and water cooling busbar structure have been proposed and investigated in this paper. For each cooling scheme, a 3D finite model based on the proposed structure has been developed to perform the electromagnetic and thermal analysis to predict their operation behavior. Comparing the analysis results of the three different cooling patterns, water cooling has more advantages than the other patterns and it is selected to be the thermal dissipation pattern for the AC busbar of ITER PF converter unit. The approach to qualify the suitable cooling scheme in this paper can be provided as a reference on the thermal dissipation design of AC busbar in the converter system.

Design of Balanced Reactor Welded with Water-Cooled Aluminum Busbars

A new process of welding aluminum water-cooled busbars is proposed, It can not only reduce the weight and cost, but also improve the dynamic and thermal stability. Furthermore~ both finite element method analysis and a prototype test testify the advantages of the design which is not limited by load current and provides a new approach for water-cooled reactors.

Design of a DC Busbar for the ITER PF Converter

The DC busbar is an important component for the ITER PF converter module to connect the converter and the reactor. This paper analyzes different cross-sections and different thermodynamic properties under natural-cooling and water-cooling conditions, and simulation is carried out by the software of the finite element method （FEM）. The result of the analysis shows that the water-cooling method is the better choice for the DC busbar.

Effect of laser surface melting treatment on properties of electric copper busbar joints

Electrical conductance and temperature of electric copper busbar joints were measured under different torque moments. Experimental results show that laser surface melting can increase hardness and refine structure of the copper, and it does not deteriorate electric resistance. Meanwhile, the temperature of laser treated joints under electric current is slightly lower than that of original sample. Salt spray test shows that laser treated sample has better salt spray corrosion resistance than the original sample does. The electric resistance of both laser treated and original samples are increased with salt spray time. For the same salt spray time, the electric resistance of busbar joint is decreased with increasing torque moment.

Busbar Differential Relaying Method Based on Combined Amplitude and Phase Information of High Frequency Transient Currents

Busbar differential relaying method based on combined amplitude and phase information of high frequency transient currents is put forward in this paper for the speed and reliability problems of busbar protection based on fundamental frequency. Under the analysis of features of bus high frequency differential currents, complex wavelet analysis is used to extract the amplitude and phase features of 1/4 period high frequency differential currents, and amplitude and phase information are used to form the polar coordinates. Bus fault is identified intuitively and precisely according to polar locus differences. This polar coordinates represented busbar differential protection scheme based on high frequency transient signals can not only avoid TA saturation, realizing quick protection, lots of PSCAD/EMTDC simulations also show that this busbar differential protection scheme works well under different fault conditions.

Simulation of Space Charge Impact on Partial Discharge Inception Voltage in Power Busbars Dedicated to Future Hybrid Aircrafts

Reducing greenhouse gases, saving energy resources and mass optimization require technological changes towards increasingly electric vehicles. At the same time, performance improvement of semiconductor and dielectric materials further promotes electronic components confinement, resulting in a significant increase of embedded power densities. In the particular case of future hybrid propulsion aircrafts, electrical power that intended to supply reactors would be converted through power electronics components mounted on power busbars and insulated by solid dielectrics materials. These dielectrics materials have to respond to various electrical constraints of use (HVDC), in spite of environment change of aircraft parameters such as low pressure, temperature and thermal cycles, humidity... Unfortunately, partial discharges phenomenon is the most problem within electrical insulation system (EIS). Based on a topological model of power busbars designed for power converters dedicated to hybrid aircraft, partial discharge studies were conducted by simulation in various charging conditions of a PTFE insulator. Simulation results, which focus on electric field thresholds criteria of partial discharge inception voltage in air, reveal a net sensitivity of a space charge accumulation and distribution on dielectrics behaviour even for low space charge density, depending on their location in dielectrics. Compared to the behaviour observed with implanted homocharges, when by increasing homocharges density from 0.5 C/m3 to 2 C/m3 we observe a decrease of electric field by 450%, simulation results show a highest risk of partial discharge inception when heterocharges are accumulated inside dielectrics. Their accumulation increases the electric field in triple points beyond electric field thresholds of partial discharge inception in air. The simulated electric field reaching 22 kV/mm with only 2 C/m3 of heterocharges density accumulated in dielectric/busbars interfaces.

Semantic-driven method for designing 3D busbars

Traditional busbar design is inefficient, costly, and error-prone because of frequent changes of requirements. This paper proposes a semantic-driven method for designing 3D busbars to solve this problem. The design process contains two main parts, namely, semantic-driven routing design and automatic routing segmentation. Semantic-driven routing design creates a relation table between electrical semantics and 3D modeling parameters, as well as helps designers create routings efficiently using electrical parameters as input. Automatic routing segmentation can convert routings into busbar segments that also include manufacturing information. Because the design operations are associated with one another, the resulting busbars can automatically be changed in real time when requirements are changed.

海上风电低频输电系统快速母线保护

海上风电低频输电系统母线故障后,换流器型电源等效电势与阻抗因控制的切换与调整过程,不再像传统电网可视为恒定。文中理论分析了母线电流差动保护适应性,明确故障控制策略对差动保护灵敏度的影响方式。利用母线区内外故障所对应的故障等效模型不同,提出基于时域全量模型识别的母线保护。该保护原理反映被保护元件自身拓扑的变化,理论上具有不受电源特性影响的优势,同样适用于其他换流器型电网。同时,所提保护在时域中实现,不存在相量提取问题,动作速度快。最后,在PSCAD/EMTDC中搭建了仿真模型,验证了所提母线保护的可靠性和快速性。

基于馈线和电流的专用轨回流牵引供电系统接地故障保护

对于专用轨回流牵引供电系统,负极回流轨对地具有良好的绝缘特性,极大地限制了正极接地故障所产生的短路电流。由于负极母线电位下降、接地电阻较大等原因,现有的正极接地保护在实际应用中暴露出选择性差、灵敏度低等问题。本文通过对专用轨回流牵引供电系统短路电流以及负荷电流的潮流分析,提出以供电区间馈线和电流作为正极接地故障判断的特征量,并设计基于该故障特征量的保护方案,基于MATLAB/Simulink仿真系统,验证了该保护方案的有效性。

动力电池系统内模组汇流排可靠性浅析

近年来,随着全球环保意识的不断提升,新能源汽车逐渐成为全球汽车产业发展的重要方向,动力电池作为新能源汽车的核心设备,其安全性成为电动汽车发展的关键。行业内针对动力电池系统的热特性开展了大量研究,这些研究大多数只考虑整个动力电池包或者电池模组层面的研究。然而,在动力电池Pack结构设计中,汇流排作为连接的关键零件,其热性能也至关重要。本文以方形动力电池系统内模组研发为基础,论述了电池系统内汇流排的结构设计、强度分析、散热分析方法,同时浅析了过程参数可靠性设置以及产品使用可靠性的验证。希望文中论述的基本过程和基本方法能为电池系统的研发提供一些借鉴。

储能PCS叠层母线研究

该研究以储能变流器(PCS)叠层母排就如何降低电感为研究对象,进行了PCS及电感原理、叠层母排导体及绝缘材料选型介绍。通过电容端子排布、电容端子间距、IGBT是否偏心、母排层数等因素对电感的影响进行仿真研究。最后,对叠层母排及组装成子模块进行电气测试。结果表明:电容端纵向布置,N极靠内,电容引脚间距减小,IGBT居中布置且将3层极板改为2层极板,N极板与负极板分布在同一层,电感最优,为5.13 nH,电感降低29%。叠层母排局放测试,局放值为0.1 pC(1 kV,AC)。直流耐压测试,漏电流为0 mA(3 kV,DC)。叠层母排测试电感为5.3 nH,与仿真值保持一致。子模块测试电感为15.06 nH,满足要求。

VRML技术在面向CSCW的母线槽布线专家系统中的应用

VRML 技术是一种集成了多媒体技术和虚拟现实技术的网络 3D技术 ,利用它可以很方便地在 Web上建立一个 3D虚拟协同空间 .文中将这项技术应用到电气设计领域 ,建立了一个松散耦合的、基于 Internet/Intranet的三维异地同步 CSCW系统 ,解决了配电系统中母线槽系统设计这个三维、异地、多人的协同设计问题 .

基于电压控制区的主导节点电压校正方法

随着电力网络的不断扩大,监控节点电压越限的情况日益增多,传统的根据运行人员的经验来校正电压的方法已不能满足要求。为此,笔者利用图论的基本理论,借鉴国外电力系统电压三级控制模型的运行经验,提出了一种基于电压控制区的主导节点电压校正方法。首先利用各个电压控制区之间无功电压的弱耦合性,采用多阈值分解的分区算法,实现区域间的解耦,然后根据各个子网络的主导节点的电压进行区域内电压校正,从而将对整个网络的电压校正问题转化为各区域内部的电压校正问题,减少了无功调节设备的动作次数,提高了校正成功率,缩短了计算时间,并在实际系统中取得了良好的效果。

通用变电站操作票生成方法的研究

经过多年研究,单个变电站的操作票自动生成方法已日趋成熟。而难于生成多站通用操作票的原因在于多站操作票生成问题具有较高的复杂度。作者提出将通用变电站操作票生成问题解耦以降低其复杂度,从而实现多站系统的通用操作票的生成。将不同电压侧(负荷侧或受电侧)、不同母线接线类型、不同操作任务的操作票生成规则存储于案例库中,通用操作票生成问题解耦后,可以用每个案例库中存储的操作票生成推理规则来完成特定母线类型在特定电压侧、特定操作情况下的操作票生成。按照本文思路开发的通用操作票系统对某市局的13个变电站建立的案例库实现了对该地局39个110kV及以上变电站的通用操作票生成。

电力系统输电能力研究中PV曲线的求取

针对大型电力系统输电能力计算问题 ,提出了一种改进的 PV曲线求取方法 ,它较好地考虑了受电侧负荷增长方式与发电侧发电机功率调度方式。在追踪 PV曲线的过程中 ,改进的局部参数化方法被用于消除功率传输极限点附近潮流方程的病态现象。所提出的电压定步长下降控制思想提高了曲线的追踪效率 ,实现了自适应步长控制。 50

密集型母线槽磁场-温度场综合有限元分析

利用ANSYS有限元软件建立了密集型母线槽的磁场-温度场耦合分析模型,在计算涡流场的基础上得到焦耳热损耗,随后将焦耳热作为体积热源,通过顺序耦合方法准确地计算了密集型母线槽的温度场。耦合过程中引入了预估-校正法,以确保预估的母排和外壳温升值的合理性,从而保证焦耳热损耗和外壳对流散热系数的准确性。母排和外壳温升的计算结果与实验结果吻合得很好,误差在1.2K之内。

集中式保护测控系统中母线保护同步方案

在220 kV变电站数字化改造过程中,提出了一种应用于集中式保护测控系统的母线保护同步实现方案。介绍了集中式保护测控系统的整体方案,着重研究了母线保护多间隔的数据同步问题,并提出了采用外部时钟源对时方案解决各合并单元与保护装置间的同步问题,采用主从对时方案解决各保护装置间的重采样时刻的同步问题。通过动模试验验证了该方案的可行性。该方案大幅减少了投资,但系统集成复杂。

LTPB网络带宽分配策略的实时性能研究

研究LTPB(线性令牌传递总线 )在通信网络中保证消息实时传输的带宽分配问题 .LTPB网络带宽的分配是以保证网络消息的实时传输为目标的 ,网络中关键参数 (一定时间内发送消息的最小量 )的准确与否将关系到网络带宽分配的合理性和有效性 .通过对带宽分配方法实时特性的分析 ,发现了当前分析方法中的不足 ,提出了“最差情形”的概念 ,并以此建立了合理的推导模型 ,得出了有关LTPB网络实时性分析的关键性结果 ,并为下一步寻求更优的带宽分配方法提供了可靠的分析基础 .