Models for transmission lines with connecting transistors based on wave digital filters

Based on the theory of wave digital filters (WDFs), models are derived to simulate interconnection circuits. They contain lumped transmission line models and transmission line models derived from their partial differential equations (distributed models). Both kinds of models are implemented in the transmission line simulator ALWX in order to calculate the signal wave-forms on transmission lines and the cross-talk behaviour between them. Additional MOS transistor models extend the possible applications. Compared with other simulators, ALWX shows significant advantages in CPU time while producing results with high accuracy.     

一种利用耦合输出电感的PWM全桥变换器

提出了一种利用耦合输出电感的新型次级筘位零电压、零电流开关-脉宽调制(ZVZCS-PWM)全桥变换器.它采用无损耗元件及有源开关的简单辅助电路,实现了滞后桥臂的零电流开关.与传统的ZVZCS-PWM全桥变换器相比,这种新型变换器具有电路结构简单,整机效率高,以及轻载时能根据负载情况自动调整筘位电容的充放电电流.因而非常适合用于IGBT作为主开关的高压、大功率应用场合.详细分析了该变换器的工作原理及电路设计;在一台功率为1kW的工程样机上测出了实际运行时的波形及变换器效率.实验结果证明,该变换器能在任意负载下实现滞后桥臂的零电流开关,且满载时的效率最高达到92%.     

HVDC和FACTS控制与保护系统的实时测试技术

阐述了HVDC和FACTS控制与保护系统实时测试技术的发展和应用情况.分析了实时测试的步骤和内容,实时测试对仿真步长、等值系统及仿真模型的要求.论述了模拟仿真器与数字实时仿真系统各自的特点及数模混合实时仿真系统的结构和应用情况.提出了先进的集成混合实时仿真系统和实时数字混合接口的原理、数据交互方式和电压预测技术,对经济有效地扩大实时测试系统的规模具有重要意义.     

Design of a small‐size interlocking system with high availability

An interlocking system consists of an interlocking logical unit and a power controlling unit. After this logical unit calculates the relationship among the train position, the rail shifting position, and the signal, it decides the aspect of the signal. The power controlling unit supplies electrical power to the switch motor and the signal light according to the decision of the logical unit. This paper proposes a small‐sized interlocking system which uses a triplex redundant off‐the‐shelf controller with fail‐safe checker as an interlocking logical unit. A majority voting circuit ensures the safety of parallel output from the interlocking logical unit. This circuit satisfies the condition of total self‐checking (of D.A. Anderson) and also the condition of high availability. In other words, no single fault ever leads to a hazardous state and this circuit ensures safety after single fault occurrence. © 1999 Scripta Technica, Electr Eng Jpn, 128(2): 63–73, 1999     

Use of Constructivism and Collaborative Teaching in an ILP Processors Course

Simulators are widely used to teach instruction level parallelism (ILP) topics. A simulator called SIMDE, which combines the superscalar and very long instruction word (VLIW) approaches to ILP processors in a single environment, has been developed. SIMDE has been validated and improved using feedback from students during two academic years. Although the simulator is a valuable tool in and of itself, this paper goes one step beyond by using SIMDE with an educational methodology based on constructivism and collaborative learning. This methodology has been applied in a computer architecture course that uses the Moodle platform as a framework for collaboration between students and teachers     

基于分布式算法的时间同步系统的研究和实现

在依靠节点设备实现同步的电信网络中,为了应对由于节点交换机不能自动修正时间偏差而导致时间同步水平低下的问题,设计了一个基于分布式算法的时间同步系统。该系统独立于交换设备,以GPS为标准时间同步源,利用电信DCN网传输时间同步信息,通过NTP协议实现DCN网中各级时间服务器间同步。本文在对分布式系统时间同步算法进行研究的基础上,详细介绍了应用于接口机和交换机之间主动时间同步算法的实现原理,给出了减小系统误差的方法和系统告警注意事项。实践表明,该系统可以把全网中运行时间同步系统的设备之间的时间差控制在1 s范围内,具有较好的同步效果,值得推广。     

基于DSP控制的双模式逆变系统的研究

以往对逆变器的研究侧重于并网模式或独立工作模式,很少涉及两种模式间的切换状态.这里设计并实现了一种能在离网/并网双模式下运行的逆变器.在详细分析逆变系统独立工作和并网运行两种不同运行模式工作原理的基础上,以减小两种模态切换过程中的电压电流冲击为目标,设计了离网/并网逆变器两种模式间的无缝切换方法.系统采用TMS320L...     

A spice-based approach to steady state circuit analysis

A new SPICE-based approach for steady state circuit analysis is presented which uses SPICE computational capabilities and a master programme to carry out the periodic response. the master programme implements a suitable method for steady state analysis and is linked with SPICE only via I/O SPICE files. This allows the use of all SPICE analyses together with the new one simply by adding a new statement in the input SPICE file. In this paper the bases of this technique, including the chosen steady state method and the whole system structure, are discussed. Simulation results produced by this technique have been compared, by means of two meaningful examples, with those obtained both by SPICE and by a dedicated simulator for steady state analysis working in the frequency domain.     

基于IEC 61850的智能变电站交换机IED信息模型

分析了智能变电站中交换机在数据交换和时钟同步方面的功能,建立了基于IEC 61850标准的交换机智能电子设备(IED)信息模型,该模型由公共逻辑设备、数据交换逻辑设备和时钟同步逻辑设备组成。以不同的网络协议为对象,提出了一组新的逻辑节点类模型以描述交换机的监视信息和各种网络协议的可配置参数。最后对模型的进一步完善进行了探讨。     

启发式电力系统暂态稳定裕度在线评估方法研究

本文定义了一个能综合反映电力系统特定结构和运行方式下整体暂态稳定水平的连续指标：综合临界切除时间。结合知识库,模糊逻辑推理和综合技术,本文提出了一种能以较高精度在线估计ＧＣＣＴ值的暂态稳定估计方法。     

汽轮机数字电液控制系统仿真器的设计

随着电力系统的飞速发展,数字电液控制系统（DEH）成为当今汽轮机特别是大型汽轮机必不可少的控制系统。针对当前电厂汽轮机机组的实际要求,设计了汽轮机DEH控制系统仿真器。该仿真器通过模拟汽轮机机组的调节特性。代替汽轮机完成与DEH系统的信息通讯。运行时能动态显示各种运行参数及开关量等信息。阐述仿真器的硬件设计和软件设计方案,以及采取的抗干扰措施。电路设计简单,使用方便。该仿真器具有较好的通用性,安全又省时,灵活性大,有一定的发展前景。     

配电网电磁式柔性互联装置的快速投切方法

传统的配电网电磁式柔性互联装置采用机械式有载调压开关,存在着调节速度有限、不能频繁投切、存在机械磨损且容易产生电弧等缺点。针对这一问题,对电磁式柔性互联装置的切换开关结构进行了改进,提出了对应的快速投切方法。提出的电子切换开关结构由反并联晶闸管开关抽头和串联的多耦合电感两部分构成,可以跨多级调节,不仅能有效抑制抽头切换时的短路电流水平,实现可靠投切,还可以减少调节支路,缩减调节次数,缩短投切时间。最后,搭建了Matlab/Simulink仿真模型,验证了快速投切方法的可行性。     

Field-oriented control of an induction motor with robust on-linetuning of its parameters

This paper proposes new torque control of an induction motor, which is robust against primary resistance and adaptable to leakage inductance, magnetizing inductance, and secondary time constant. The control is based on flux feedback with a flux simulator. Since the simulator is based on a rotor current model, it is independent of the primary resistance, but uses the magnetizing inductance and secondary time constant values to estimate the flux. Parameter mismatch in the simulator detrimentally affects flux and torque responses. In order to compensate for degradation of the responses, an identifier for the magnetizing inductance and the secondary time constant is introduced. The identifier is insensitive to the primary resistance because it is based on instantaneous reactive power of the motor. Also, a leakage inductance identifier is introduced to achieve perfect compensation, which is robust against other parameters owing to instantaneous harmonic reactive power. To verify feasibility of the proposed technique, digital simulations and experimental tests have been conducted. The results have proven excellent characteristics of the drive system, which confirms validity of the scheme     

基于遗传算法的发电机模糊式综合励磁控制器的研究

本文在分析了模糊控制器工作原理及其传统设计方法的基础上,提出了一种模糊控制器的自寻优设计方案,成功地解决了在模糊控制器的传统设计方法中存在的过分依赖于设计者预先选用的启发式知识及操作者的经验等问题,并采用遗传算法（ＧＡ）实现了这一方案。用新方法设计的发电机模糊式综合励磁控制器兼顾了对发电机端电压和功角稳定的要求。仿真结果表明,新方法设计的控制器具有良好的控制效果,而且设计过程更加合理。因为这种设计     

A new general method to model signal timing of E/D NMOS logic

A new general modelling method for E/D NMOS logic is proposed and applied to the case of inverters. In this model, non-linear device currents in the large-signal equivalent circuit are reformulated by the curve-fitting technique. Then output voltage wave-forms are analytically solved region by region from the equivalent circuit. From the derived formulae, the rise/fall time and delay time can be calculated. Wide-range comparisons with SPICE simulation results were performed to verify the accuracy and the general applicability of the developed model. Two examples are given to demonstrate the applications of the developed timing model to timing analysis. It is shown that the model has a good accuracy for E/D inverters with a wide range of beta ratios, gate sizes, capacitive loads, input voltage wave-forms and device parameters. Moreover, the required CPU time and memory are small. These make the proposed modelling method an interesting approach to model E/D NMOS gates for CAD applications.     

PPIS 100系统的智能前端管理与数据采集

该文介绍了用于火电厂的生产过程监控与信息管理计算机系统（ＰＰＩＳ１００系统）的智能前端管理部分,主要包括各前端工作状态监测,模拟量前端实时数据采集,开关量状态监测及开关量变位信息存取,为监控级管理系统提供了实时信息。     

核电磁脉冲模拟器的分析和设计

从理论上分析了核电磁脉冲中的工作原理,仿真分析了峰化电容器、主开关和引线电感,阻尼电阻和主开关导通时间对输出脉冲前沿和脉宽的影响.实验最后利用峰化电容谐振充电、冷阴极撬棒管导通放电来研制出核电磁脉冲源.在实验工作空间获得前沿为10 ns、脉宽为200 ns、场强达到50kV/m的强电磁环境,适用于GJB151A-97中...     

矩形波交流原油脱水电源的研制

为了满足油田商效脱水需求.研制了一种矩形波交流原油脱水电源.大功率IGBT作为主电路开关器件,控制电路以专用脉宽调制芯片SG3525为核心.详细介绍了电源主电路、PWM控制电路和驱动电路的设计方法,并给出了电源实际工作波形.研制的电源不仅脱水速度快、脱水质量高,而且节能,已成功应用于油田现场.     

Quasi-stationary analysis of the electric field in anisotropiclaminated composites

This paper deals with the analysis of the quasistationary electric field in the presence of anisotropic laminated composites. Both cylindrical and box composite structures are examined in the two-dimensional domain. Two methods are proposed to solve the problem. The first is a numerical procedure employing the finite-difference time domain which uses a direct implicit scheme; the second is an equivalent circuit network which is solved by the use of the standard circuit simulator SPICE. For the composite box structure, the results obtained by means of the two approaches are compared; it is possible to observe a good agreement between them     

基于PTP报文的智能变电站IEEE1588交换机测试技术研究

针对智能变电站的交换机中本地时钟波动导致的时间同步系统可靠性差的问题,提出基于IEEE1588精确时钟协议（PTP）同步报文的交换机测试方法,并研发了手持式IEEE1588交换机测试仪。首先,通过协议报文获取报文时间戳、交换机驻留时间和路径延时时间;然后,计算测试仪与交换机的主从时间偏差值,得到被测交换机的同步误差;最后,通过现场测试证明所研发测试仪对交换机授时的测量和监控精度达到ns级,可满足实际应用需求。