计算串联稳压电路调整管的最大功耗的另一种方法

串联稳压电路主要工作在线性状态,因此调整管的功耗大。很多情况下调整管的损坏系因其功耗过大发热所致,所以计算调整管的最大功耗是选择调整管的关键,但一些教材中对调整管功耗的计算方法不够严密。本文利用最大功率传递定理,对调整管的最大功耗进行了分析计算。     

某型导弹发控盒电路板综合测试系统的设计

介绍了某型导弹发控盒电路板综合测试系统的硬件和软件设计,该系统以PC计算机为平台,采用总线式设计思想,实现了对电路板检测的自动化、快速化和智能化.     

大管径高温含尘气体流量计

介绍了一种新型β射线电离式气体流量计.该流量计基于标记分子法测气体流速,通过硬件模拟电路对所得微弱电流信号进行放大滤波,经A/D转换输入计算机,由软件寻峰定时,实现对大管径高温气体流量的非接触测量.设计并制作了硬件电路,给出了详细的软件设计流程图.     

An efficient,simplified multiple-coupled circuit model of the induction motor aimed to simulate different types of stator faults

This paper proposes an original simplified model aimed to simulate, an easy way, inter turns short circuit fault, phase to phase fault and phase to ground fault. In this model, the stator is considered as six magnetically coupled windings and the rotor as three not magnetically coupled R–L circuits. The paper also presents the star- and delta-connected stator configurations of the simplified model. However, the proposed simplified model is suitable only for steady-state operation. The performance of the simplified model is first verified by a comparison between the simulated current of the multiple-coupled model and the simplified model. Then, since the stator faults have an impact on the symmetrical components of the stator current, this paper uses these components to validate the behavior of the simplified model by simulation and experimentally using a 1.1 kW motor. In addition, simulated results of the simplified model for a 110 kW motor are presented in order to generalize the use of the proposed model to larger motors.     

Moving pick‐up‐type contactless power transfer systems and their efficiency using series and parallel resonant capacitors

The equivalent circuit, the efficiency, and the important characteristics of moving pick‐up type contactless power transfer systems are described. If the primary series capacitor and the secondary parallel capacitors are chosen correctly and the winding resistances are ignored, the equivalent circuit of the transformer with these capacitors becomes the same as an ideal transformer at the resonant frequency. This simple approximation helps to understand the phenomena occurring with load changes. Because the circuit analysis becomes simple, the approximate value of the power transfer efficiency can be derived. This paper describes the determination of the capacitor values, the derivation of the equivalent circuit and the efficiency, and test results. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(2): 47–54, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20970     

新型混合型限流断路器分析及试验

研究了一种基于高速斥力开关的交直流两用混合型限流断路器方案,该限流断路器在限流过程中先经过一个强迫换流过程,使得触头分离时高速斥力开关上电流减小到较小值,触头分离后再经历一个自然零电压换流过程,将斥力开关电流换流到二极管支路上.重点对限流断路器换流过程进行了理论分析及仿真,分析了其可能出现的4种分断情况.研制了400V/500A限流断路器样机,并进行了不同短路电流上升率的限流试验,验证了理论分析的正确性.     

汽轮发电机转子匝间短路故障的有限元分析

以300 MW汽轮发电机为例,在建立其二维有限元数值模型基础上,对瞬变电磁场有限元分析过程进行了分析与推导。同时阐述了汽轮发电机在不同工况下磁场分布情况,以及转子绕组发生不同匝间短路故障时通过探测线圈波形进行计算与分析。     

基于IEC61850的万能式断路器模型构建

信息建模是IEC61850标准的核心内容,该标准规定了变电站信息模型和建模方法.首先,对IEC61850标准的特点进行了简要介绍,研究了基于IEC61850标准的建模技术,对智能电子设备的数据模型进行了分析,通过对服务器、逻辑设备、逻辑节点以及数据对象的分析,详细说明了智能电子设备的建模方法.然后,以万能式断路器为例进行了建模,完整地描述了断路器的功能,对功能进行了分解,以保护功能为例完成了对逻辑设备的建模,并对瞬时过流保护逻辑节点PIOC以及包括的数据对象Oper进行了建模,分别对各类数据对象和数据属性进行了说明.     

基于负序电压分布的发电机定子匝间短路保护

提出发电机定子绕组匝间短路保护新判据方法,包括主判据和闭锁判据.主判据由发电机机端负序电压和中性点负序电流构成;闭锁判据由发电机机端负序电压、主变高压侧负序电压、主变中压侧负序电压、高厂变1分支负序电压、高厂变2分支负序电压构成.如果主判据为真,再判断闭锁判据是否为真,如果闭锁判据也为真,则立即闭锁保护,否则延时保护动作并发告警信号.所提方法不仅可对发电机的各种非对称故障进行反应,还可以对主变及厂用变压器的一部分内部故障进行反应;与纵向零序电压方案相比较,可不增加一次设备并且容易双重化;在靠近发电机中性点处相间故障时,可得到较高的灵敏度.     

磁路独立组合转子复合励磁发电机的设计

复合励磁发电机在移动电源领域有着广泛的应用前景。该文提出了一种磁路独立组合转子复合励磁发电机,介绍了其结构和磁路特点。在此基础上,提出了电机的电磁设计方法,并推导了电机重要参数E0、Xad、Xaq的计算方法。设计了一台额定功率为25kW的样机,样机试验结果表明,设计计算值准确,电机性能均达到了要求。