微型燃气轮机分布式供能系统的控制

微型燃气轮机分布式供能系统能够实现天然气清洁、高效、灵活利用,目前已得到重视和应用.结合上海紫竹科学园区内分布式冷热电联供系统的实际应用,介绍了一种以天然气为燃料、微型燃气轮机为原动力的分布式冷热电联供系统,详细阐述了冷热电联供系统在供气,发电,供热和制冷方面的控制.     

激光供能混合式光电电流互感器

介绍了一种用激光供电的混合式光电电流互感器（EOCT）的原理和结构方案,并分析了系统整体测试结果。     

以微型燃气轮机为核心的分布式供能系统

针对以微型燃气轮机为核心的分布式供能系统，结合国外微型燃气轮机的研究发展及应用情况，叙述先进的微型燃气轮机技术进展及特点，对以微型燃气轮机为核心的小型冷热电联供系统和微型燃气轮机-燃料电池混合系统进行探讨，展望微型燃气轮机分布式供能系统在我国的应用前景。     

以微型燃气轮机为核心的分布式供能系统方案

简要介绍了分布式供能系统及微型燃气轮机的相关概念,着重分析了以微型燃气轮机轮机为核心的冷热电联供系统和微型燃气轮机-燃料电池联合循环系统,并将这些供能系统以模块化的形式表示.在模块化组合形式的基础上提出相关结合技术和优化方法,为分布式供能系统的建模与进一步的仿真优化打下良好的基础.     

基于多应力条件的激光供能系统寿命预估

搭建激光供能系统,通过光纤进行高电位和低电位数据通信和能量传输,具有良好的抗干扰能力和稳定性.最近,在多应力条件下半导体器件老化问题受到较大关注.单应力法在设计阶段和老化研究中相对简单,但不适合多应力的实际工作条件.现有的多应力老化研究大多基于电子元器件,并未研究整个系统的可靠性.基于Arrhe-nius模型、逆幂率模型及尼尔森的广义对数线性模型建立激光供能系统的多应力寿命预估模型,该模型根据不同的温度应力和电压应力,得到实际的可靠度曲线,预估出整个激光供能系统的可靠度,根据可靠度来确定系统的零件更换时间,完成零件的及时更换,确保长期高效的工作,避免由零部件损坏带来的突发状况.     

新型燃料电池可为微型直升机供能

据美国科学日报报道,不久的将来,人们将看到一架20cm长的微型直升机在塌陷建筑物中搜寻遇难者或勘测受污染地区。这种微型直升机能够在空中飞行工作主要取决于其轻质量燃料电池,这种新型燃料电池仅重30g,却能输出功率12W。     

高压ECT中激光供能电源的设计

激光供能作为一种新的供能方式逐步为高压电子式电流互感器设计所采用。设计了一种用于高压电子式电流互感器的激光供能方案,提出了一种激光供能与异步串行通信复用的功率激光器驱动方法,具体给出了激光器的驱动电路、保护电路和自动恒温控制方案,并在此基础上提出了MCU控制系统的模型。最后对高压侧的高效率光能-电能转换电路进行了设计。     

分布式供能系统控制的设计和应用

分布式供能系统是可以布置在用户附近并独立提供电、热或(和)冷的小型模块化能源系统,具有环保高效、使用安全、操作方便等特点。结合上海紫竹科学园区内的冷热电联供系统的实际应用,介绍一种典型的以天然气为燃料、微型燃气轮机为原动力的分布式冷热电联供系统;详细阐述了冷热电联供系统以可编程控制器(PLC)为核心的控制系统的控制功能、结构、硬件和软件组成及其实现方法。     

高压直流断路器电力电子器件供能技术

高压直流断路器受限于运行方式,其内部大量电力电子器件驱动板卡无法通过系统自取能工作,是高压直流断路器研制的主要难点之一。该文基于500kV高压直流断路器中电力电子器件绝缘栅双极型晶体管(IGBT)驱动板卡的负载特性,提出了对地级、层间级和组件级的分层隔离供能方法,开展了对地隔离供能变压器电磁场、机械和热的多物理场仿真研究,并对IGBT器件高电位驱动板卡的供能线圈进行了设计,通过有限元仿真模块Maxwell和电路仿真模块Simplorer搭建了供能线圈和驱动负载的仿真模型,进行了场路耦合联合仿真,最后在500 kV高压直流断路器上试验验证了所提供能技术的可行性及可靠性。结果表明:通过分层次的隔离供能,可为各层供能线圈提供稳定的输入电流,从而可靠地为电力电子器件高电位驱动板卡提供电源,不仅解决了高压直流断路器无法通过系统直接取能的难题,还能显著减小供能设备的绝缘水平要求,降低研制难度,并已在±500kV张北柔直工程中应用。采用多级串联的对地隔离变压器能够满足500 kV电压等级的绝缘要求,内部温升小于30 K,且能够满足9级烈度抗震要求。采用硅钢片工频取能的供能线圈能够满足高电位驱动板卡5 VA的负载容量要求,且结构尺寸小,易于大规模工程化应用。     

A low‐power,area‐efficient multichannel receiver for micro MRI

A new integrated, low‐noise, low‐power, and area‐efficient multichannel receiver for magnetic resonance imaging (MRI) is described. The proposed receiver presents an alternative technique to overcome the use of multiple receiver front‐ends in parallel MRI. The receiver consists of three main stages: low‐noise pre‐amplifier, quadrature down‐converter, and a band pass filter (BPF). These components are used to receive the nuclear magnetic resonance signals from a 3 × 3 array of micro coils. These signals are combined using frequency domain multiplexing (FDM) method in the pre‐amplifier and BPF stages, then amplified and filtered to remove any out‐of‐band noise before providing it to an analog‐to‐digital converter at the low intermediate frequency stage. The receiver is designed using a 90 nm CMOS technology to operate at the main B₀ magnetic field of 9.4 T, which corresponds to 400 MHz. The receiver has an input referred noise voltage of 1.1 nV/√Hz, a total voltage gain of 87 dB, a power consumption of 69 mA from a 1 V supply voltage, and an area of 305 µm × 530 µm including the reference current and bias voltage circuits. Copyright © 2013 John Wiley & Sons, Ltd.     

低功耗水声接收机系统设计

为了接收水下目标回波,研究设计了一款低功耗水下接收机。由于信号发射功率和传播过程中强干扰噪声影响,信号发生衰减、畸变、混响等现象,致使接收机输入端信号动态范围较大,直接影响后端数字处理。系统采用硬件电路实现恒Q的多频率接收,并采用AGC实现大动态范围的压缩和相位幅度的一致性。考虑到所处环境,降低元器件功耗以及不工作时DSP处于关机状态,海试结果表明该系统能有效降低功耗,实现动态范围大、灵敏度高、一致性好等优点。     

Low‐power design of CMOS baseband analog chain for direct conversion receiver

A low‐power CMOS receiver baseband analog (BBA) circuit based on alternating filter and gain stage is reported. For the given specifications of the BBA block, optimum allocation of the gain, input‐referred third‐order intercept point (IIP3), and noise figure (NF) of each block is performed to minimize current consumption. The fully integrated receiver BBA chain is fabricated in 0.18µm CMOS technology and IIP3 of 30 dBm with a maximum gain of 59 dB and NF of 31 dB are obtained at 3.6 mW power consumption. Copyright © 2008 John Wiley & Sons, Ltd.     

新型全集成CMOS射频接收器低噪声电源系统

针对CMOS射频接收器芯片,提出了一种新型全集成电源系统方案,相对于传统低压差线性稳压器（LDO）电源,噪声性能显著提高。在对片内模块电源域合理划分的基础上,设计了低噪声的新型电压源取代传统的带隙基准源（Bandgap）作为LDO提供参考电压,并通过对参考电压值巧妙设计,避免了使用LDO电阻反馈网络来调节输出电压,进一步减小了电阻引入的噪声。结合数字校准电路,本系统可以为片内各电路提供准确的电源电压。该设计在Smic0．18m工艺下后真结果表明,在100kHz处,新型参考电压源输出噪声为16．38nV／√Hz,片内电源输出噪声仅为21．28nV/√Hz。     

GaAs MESFET脉冲微波功率器件瞬态热场模型

GaAsMESFET微波功率放大器工作在脉冲周期状态下,由于自热效应,在很短的时间内(100μs数量级),芯片沟道温度可能产生十几度甚至几十度的变化,这种剧烈的温度变化导致功放性能的变化也是不能忽略的。本文通过建立、求解热扩散方程及能量平衡方程,建立起沟道温度的一维瞬态热模型。     

Reduction of power fluctuation by distributed generation in micro grid

Renewable forms of energy such as wind power or photovoltaic energy are environmentally focused, but the fluctuation of the output power of such renewable forms of energy may cause excessive variation of the voltage or frequency of the grid. Increasing the amount of renewable energy would degrade the quality of the grid. Micro grids, in which dispersed power sources compensate variations in the generation of renewable energy, can expand the limits of installation of renewable forms of energy by maintaining the quality of the interconnected grid. This paper discusses the use of gas turbines to absorb power variations from wind generation and the loads. In order to control the output power, gas turbines must run under partial load, which results in lower efficiency. An evaluation of the micro grids is made with consideration of their efficiency, the installed capacity of wind power generation systems, and frequency stability for islanded operation. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 22–29, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20462     

A novel low‐power receiver topology for RF and microwave applications

A novel low‐power receiver topology for radio‐frequency and microwave applications is presented. The proposed solution exploits a simple connection between the low‐noise amplifier and the subsequent mixer, which is realized by means of a high‐value resistor and a current mirror, achieving low noise and high linearity performance with an extremely low power consumption. The criteria for its optimal design are derived in order to accomplish the main trade‐offs among noise figure (NF), linearity, and current consumption performance. As a case of study, the new topology has been designed in the case of I/Q direct conversion receiver for IEEE 802.15.4 standard (ZigBee) applications at 2.45 GHz. The receiver exhibits a NF of 8.7 dB, 50Ω input impedance, a voltage gain of 26 dB, an input‐referred third‐order intercept point of ?13 dBm, and a power consumption of 8.6 mW, which represent one of the best performance trade‐offs obtained in the literature. Copyright © 2008 John Wiley & Sons, Ltd.     

质子辐射下GaAs/Ge太阳电池的性能退化

对GaAs/Ge太阳电池进行了质子辐射实验.质子辐射的能量为70～170 keV,辐射的剂量为1×109～3×1012 cm-2.研究结果表明,GaAs/Ge太阳电池具有一定的抗辐射性能;能量小于200 keV的质子辐射中,质子辐射能量相同条件下,随辐射剂量的增加,电池性能参数短路电流Isc、开路电压Uoc、最大功率Pm和填充因子FF衰降增大;质子辐射 剂量相同条件下,辐射能量越高,太阳电池性能衰降越大;在所有测试参数中,最大功率Pm的退化最为明显.     

Low‐voltage low‐power CMOS receiver front‐end for gigabit short‐reach optical communications

This article presents a new CMOS receiver analog front‐end for short‐reach high‐speed optical communications, which compensates the limited product bandwidth length of 1‐mm step‐index plastic optical fiber (SI‐POF) channels (45 MHz · 100 m) and the required large‐diameter high‐capacitance Si PIN photodetector (0.8 mm–3 pF). The proposed architecture, formed by a transimpedance amplifier and a continuous‐time equalizer, has been designed in a standard 0.18‐µm CMOS process with a single supply voltage of only 1 V, targeting gigabit transmission for simple no‐return‐to‐zero modulation consuming less than 23 mW. Experimental results validate the approach for cost‐effective gigabit SI‐POF transmission. Comparative analysis with previously reported POF receivers has been carried out by introducing a useful figure of merit. Copyright © 2012 John Wiley & Sons, Ltd.     

电力受端系统的稳定问题及其对策分析

电网可分为送端系统、受端系统和输电网络三个部分。其中,受端系统是整个电力系统的核心,受端系统的安全稳定性关乎着全系统的安全稳定性。该文首先指出了我国电力受端系统中存在的一些普遍的稳定性问题。然后针对这些问题提出了一系列增强受端系统稳定性的对策,最后指出加强最高一级电压的网络建设和提高电压支撑水平是加强受端系统稳定性最根本性的措施。