基于MPPMSG及混合式3L变流器的新型风电变换系统的设计和比较

在MW级大功率直驱风电系统中,发电机出口电压等级经常采用较低的690V,因此额定电流等级比较高,这对于全功率变流器设计是不利的.常规的解决方案是采用传统的两电平变流器并联来分摊容量,但是这是一种效率不高的解决方案.相比之下,多电平变流器具有较高的效率以及优越的谐波性能,只是在低压应用中半导体成本很高,而且还存在电容电压...     

浙赣电气化铁路江西段开放式电能质量监测系统的开发与应用

针对浙赣电气化铁路江西段对电能质量运行管理的要求,研究开发了开放式电能质量综合监测系统。系统软件采用模型驱动架构的设计思想,遵循IEC 61850标准进行电能质量对象建模,利用电能质量数据集中器实现子站系统异构设备的接入,解决了现有电能质量监测系统在开放性、标准化、自动化等方面存在的技术问题,实现了对浙赣电气化铁路沿线江西段14个子站不同厂家与不同型号产品的接入和电能质量的实时全局监测,为电力和铁路部门对电气化铁路电能质量的监控分析和治理提供了良好的平台。     

Control Power Self-Generation and Sensor Integration in Emitter Turn-Off Thyristor

This paper highlights the design and demonstration of control power self-generation and integration in the emerging new power semiconductor switch emitter turn-off (ETO). It also discusses a method that is utilized to achieve complete sensor integrations in the ETO. Conventional high-power devices require dedicated external power supplies with isolation capability to operate. An isolation transformer lowers the system reliability and increases the cost of the power converter. At the same time, conventional converters rely on expensive external sensors to gather the voltage, current, and temperature information. The emerging ETO is a fully optically controlled power switch: The internal control power is self-generated; voltage, current, and temperature sensors are also integrated in the device.     

Analysis and design of a three-phase offline DC-DC converter withhigh-frequency isolation

Single-phase offline switch mode rectifiers (or offline DC-DC converters) face severe component stresses in higher than 10kW applications. The authors show that in three-phase, switch-mode rectifier (SMR) topologies' component stresses are reduced, and performance is improved substantially. These improvements include faster response times, reduced switching stresses of the power semiconductor devices, and reduced size and ratings of associated reactive components. The authors also present an analysis and design approach for three-phase SMR converters under large-input voltage and load variations. Output voltage control is achieved by varying the duty cycle of the inverter power semiconductor switches. Theoretical results are verified experimentally     

Adaptation of a traction DC power system for high-speed traffic

Ways to develop and improve traction power-supply systems and adapt them for high-speed highways are considered. One way to improve a traction power-supply system and make it more efficient is to increase the nominal voltage in the dc traction network up to 24 kV. This allows one to increase the throughput and carrying capacities of railways, increase the distance between substations, reduce the cross section of traction-network wires, and significantly reduce power losses in power-supply facilities. All this, alongside the absence of unbalanced supply voltage and inductive losses, as well as a significantly lower electromagnetic action on the infrastructure under dc conditions, results in a greater efficiency than in the case of any alternating- current traction power systems of alternating current. A mathematical model of dynamic electromagnetic processes in electrical circuits with semiconductor converters is fleshed out. Analysis and synthesis of electromagnetic processes and the main characteristics of multipulse converters, as well as a comprehensive technical and economic comparison, shows that 24-pulse rectifying circuits with a serial connection of threephase bridge are most efficient for these systems. These rectifiers provide an improvement in the quality of electrical energy not only for the primary power-supply system, but also for the traction network. They allow one to use simpler and more economical active-passive smoothing filters that provide the electromagnetic compatibility (EMC) of a new traction dc power system with the communication and railway automation facilities. In addition, the use of 24-pulse rectifiers can allow one to significantly reduce the consumption of reactive energy, reduce power losses in a traction network, and increase the efficiency of traction substations.     

现代化水电站综合自动化方案——兼谈三峡左岸电站自动化方案

论述了现代化水电站综合自动化必须具备的高速双网络拓扑结构、主体冗余性、主体一致性、完全分布性、数据库的完备性、监控对象的全面性、主体功能软件的自适应性、完备在线维护性、采用功能块程序设计语言、设备性能评估系统、信息管理系统及目标运营极大化等特征,并提出了具有现代化特征的三峡左岸电站自动化方案,该方案突破了传统中控室必须建在厂房的概念,提出了励磁处理单元、调速处理单元的新设想,最大限度的实现系统资源共享及减少子系统间的电缆连接.此外,利用LPU对电站的辅助设备实行全面控制,并在电站的厂用电6 kV开关、400 V开关实现备自投功能及运行方式自动选择功能.整个电站自动响应调度中心的控制,符合国家电力公司"无人值班"(少人值守)的一流电站的要求.     

ZigBee技术在远程计算机电源控制系统中的应用

论述了在无人值守的远程计算机管理中,如何实现在远程控制计算机的电源开关。采用软、硬件相结合设计方案,ARM7嵌入式处理器为硬件核心,设备之间采用ZigBee通信,网关设备通过GPRS网络与服务器通信,电源控制设备通过GPIO口控制外部继电器开关,实现弱电控制交流强电输出的开关切换和模拟计算机的电源按键动作。以Delphi编写服务器端软件、被控计算机控制端软件和管理端软件,配合Or-acle 10g数据库和TCP/IP协议,实现电源控制功能。     

Investigations of the usefulness of average models for calculations characteristics of buck and boost converters at the steady state

This paper deals with the problem of the analysis of boost and buck converters at the steady state with the use of the method of average models. The usefulness of this method is examined by comparing the boost and buck converters characteristics at the steady‐state obtained both with the transient analysis with physical models of semiconductor devices and the examined method as well. The accuracy of the method of the average models is investigated with respect to the values of the circuit load resistance, the pulse‐duty factor and the frequency of the signal controlling the power switch. Copyright © 2009 John Wiley & Sons, Ltd.     

Non‐isolated single‐switch DC–DC converters with extended duty cycle for high step‐down voltage applications

Several new topologies of single‐switch non‐isolated DC–DC converters with wide conversion gain and reduced semiconductor voltage stress are proposed in this paper. Most of the proposed topologies are derived from the conventional inverse of SEPIC (Zeta) converter. The proposed topologies can operate with larger switch duty cycles compared with the existing single switch topologies, hence, making them well suitable for high step‐down voltage conversion applications. With extended duty cycle, the current stress in the active power switch is reduced, leading to a significant improvement of the system losses. Moreover, the active power switch in some of the proposed topologies is utilized much better compared to the conventional Zeta and quadratic‐buck converters. The principle of operation, theoretical analysis, and comparison of circuit performances with other step‐down converters are discussed regarding voltage and current stress and switch silicon utilization. Finally, simulation and experimental results for a design example of a 50 W/5 V at 42‐V input voltage operating at 50 kHz will be provided to evaluate the performance of the proposed converters. Copyright © 2014 John Wiley & Sons, Ltd.     

500kV双河变电站监控系统综合自动化改造设计

介绍了500kV双河变电站综合自动化改造设计的指导思想,提出了变电站综合自动化系统的具体功能要求。将原有的双河变东方监控系统改造为分层分布式结构,设计了自动化装置、继电保护设备的改造方案,以及在改造过程中如何可靠的与网省局调传输远动信号的解决方法。     

A diagnostics method for signal lamp glowers

Modern railway automation and remote control systems are equipped with advanced self-diagnostics facilities. This article is devoted to the development of continuous technical state control of turned-off signal lamps. Application of pulse control using special pulses is proposed. The advantage of such a control circuit is its low sensitivity to the shunting effect of the signal transformer magnetizing inductance. The correct selection of the pulse parameters allows one considerable decreasing the shunting influence of the cable line capacity. It is shown that the pulse test circuit can be implemented by means of the up-to-date contactless semiconductor component base. The pulse control principles of the turned off signal lamps are discussed. An engineering solution enabling one to generate test pulses 5 ms in duration with a time interval of 200 ms is given. The signal processing principles on the control circuit output are considered. The aforementioned solution is integrated to the structure of the signal lamp control power module.     

CW1开关双电源切换回路在实际工程中的应用

介绍了双电源供电形式和应用场合。分析了进线开关和母线联络开关在双电源自动切换方案中的控制原理。指出了设计时选择带自动控制器的双电源开关,由智能控制器来控制开关的投切,还可以选择具有RS-485通信接口的智能开关来进行远程控制开关的投切,实现高度自动化,这也是今后智能开关柜的发展方向。     

A lossless switching technique for smart grid applications

Smart grid is an upgrade of the existing electricity infrastructure in which integration of non conventional energy sources are an integral part. This leads to the introduction of harmonics and increased switching losses in the system. Thus there is a need of loss less switching techniques for smart grid applications. Switched mode power supplies (SMPSs) are being extensively used in most power processes [1]. Developments were carried out centered on hard switched converters, where switching frequency is limited to 10 s of kHz [2]. The uses of soft switching techniques, [3], [4], [5], [6] zero voltage switching (ZVS) or zero current switching (ZCS), is an attempt to substantially reduce the switching losses and hence attain high efficiency at increased switching frequency. The soft-switching topologies belong to families namely resonant load converters [3], resonant switch converters [2], [4], resonant transition converters [5], [6], and most recently active clamped PWM converters [7], [8], [9]. The active clamp topology adds an active clamp network, consisting of a small auxiliary switch in series with a capacitance plus the associated drive circuitry to the traditional hard switch converters. The proposed paper basically deals with the design, modeling and simulation of a ZVS–PWM active clamp/reset forward converter having features like zero switching power losses, constant frequency and PWM operation, Soft-switching for all devices and Low voltage stresses on active devices due to clamping action.     

基于MPU-6050无线遥控电气开关的研究与设计

无线电遥控器是利用无线射频信号对远方的机构进行控制的遥控设备.介绍了一种基于MPU-6050无线遥控开关系统的设计方法,并对该系统的组成结构和工作原理进行了详细的说明.为了减少传统无线遥控开关收发过程中编码、解码出现错误,提高无线遥控的精准度,并减少无线遥控开关的功耗,体积等.该系统直接用MPU-6050 6轴融合后的四元数处理后的数据作为开关的控制信号,以STM32F103ZET6为主控芯片,NRF24L01为无线收发模块,设计了一种基于MPU-6050的无线遥控照明电气开关,对整个系统进行了硬件和软件的设计,并通过keil进行了硬件仿真,而且对整个系统进行了实验验证.仿真和实验结果表明,该系统实现了控制电气开关的功能,并提高了无线遥控开关的精准度,减小了无线遥控开关的功耗和体积.     

基于半导体功率损耗的小型风电变换器可靠性研究

基于半导体功率损耗,针对小型风电永磁电机常用的Boost(Intermediate boost converter,IBC)、Buck-boost(Intermediate buck-boost converter,IBBC)、背靠背(Back-to-back converter,BBC)、矩阵(Matrix converter,MC)变换器可靠性进行分析,确定变换器在特定风速下的失效周期和可靠性。在统计学基础上,建立了变换器元件的故障率统一计算模型。通过计算电力电子器件的开关损耗和导通损耗,确定Boost变换器相对其他变换器具有最高的失效周期。同时确定出变换器组件中,逆变器可靠性是影响变换器可靠性最重要的因素。通过现场数据比较四种变换器可靠性和使用寿命,证明理论分析是正确的。     

适用于工业企业变电站的保护测控一体化装置开发

大型工业企业变电站对自动化产品的需求与日俱增,但与电力系统主电网中的变电站相比有其特殊性,借鉴成熟的电力系统变电站综合自动化技术和以太网通信技术,基于新型的MCU硬件平台和VxWorks嵌入式操作系统,开发了一套系列化的保护测控一体化装置,为实现企业变电站的自动化提供了先进的解决方案。针对目前企业变电站中应用的保护测控装置普遍存在的问题,提出了相应的解决方法,实践证明该装置能很好地适应工业企业变电站的特殊运行要求。     

AC/DC/AC PWM converter with reduced energy storage in the DC link

The paper introduces the family of quasi-direct converters, i.e., forced-commutated AC/DC/AC power converters including small energy storage devices in the DC link. In particular, the case of the three-phase to three-phase quasi-direct power converter is considered. Since energy storage minimization calls for instantaneous input/output power balance, a proper control strategy is needed. The paper describes a simple and effective control technique which also provides high-power factor and small distortion of the supply currents. After a discussion of the general properties of quasi-direct power converters, design criteria of both power and control sections are given, and experimental results of a 2-kVA prototype are reported     

Analysis and design of a low-cost converter for switched reluctancemotor drives

The analysis and design of a low cost, one-switch-per-phase power converter topology suitable for low performance switched reluctance motor (SRM) applications are described. The converter has the advantage of using a minimum possible number of semiconductor devices in the power circuit without the attendant need for a bifilar winding, so that its drive requirements are minimal and the windings are simple. This is achieved by eliminating the additional semiconductor switch(es) normally required for regeneration. Energy stored in the phase windings during conduction time is partially dissipated in a resistor, whereas the rest is converted to mechanical power. A complete steady-state analysis of the drive including the input filter parameters is given. Closed-form expressions for determining the current and voltage stresses on the semiconductor devices are derived, and they are cast in normalized form for use in selecting the ratings of the power devices. Experimental verification of the key results is provided for a 6/4-pole SRM drive system     

Comparative study of semiconductorpower losses between CSI-based STATCOMand VSI-based STATCOM, both used forunbalance compensation

In this paper, we present a detailed procedure to determine the semiconductor losses for both structures of a shunt STATCOM (Static Compensator), STATCOM based on Current Source Inverter (CSI) and STATCOM based on Voltage Source Inverter (VSI), both used for voltage unbalance compensation. As a first step, we study the VSI-based STATCOM and the CSI-based STATCOM used in high speed railway substations. Then we analyze the design and the sizing of the unbalance compensator in order to obtain an unbalance factor that does not exceed the limits imposed by the standards or by the energy provider. Following that, we compare the performances obtained with both structures VSI-STATCOM and CSI-STATCOM, after calculating the semiconductor power losses in the STATCOM converters. Finally, we validate our approach by simulation over real data of unbalance compensation caused by the new high-speed railway in Morocco. We use the tools MATLAB / Simulink/Simpowersys for performing our simulations.     

实现配电环网可靠自动转供电功能的关键策略

配网馈线自动化是提高供电可靠性的有效措施,是智能电网建设的重要一环。对目前普遍应用的就地型馈线自动化装置自动转供电的策略进行分析、研究,指出该动作策略设计上的不足及可能给电力系统及运行管理带来的危险,并以中山供电局作为典型案例,提出了对联络开关FA装置进行技术改造等以实现可靠的配电环网自动转供电目标的解决方案,为配网馈线自动化的深层应用及开发提供参考。