On solving broadband matching design equations

Algorithms are presented which may be applied to:

• (1) Determining the real solution set in one variable plane, of a polynomial equation in many variables, where each variable other than the chosen one is confined to given intervals.
• (2) Determining the real solution set in one variable plane, of a system of polynomial equations and inequalities, where the number of variables is greater than the number of equations, and each variable other than the chosen one is confined to given intervals.

These algorithms are applied in certain cases of broadband matching design, which presented in the past some numerical difficulties. Illustrative examples are provided.     

太阳电池用Bragg反射器的设计及研究

为提高GaAs/Ge太阳电池对光的吸收 ,我们对Ge衬底Bragg反射器进行了研究。根据GaAs材料对太阳光谱的吸收特点 ,通过转移矩阵的方法 ,对中心波长为 85 0nm的AlxGa1-xAs系材料Bragg反射器进行了光反射的理论计算和设计。依据理论设计 ,利用低压金属有机化合物化学气相沉积 (LP MOCVD)技术在Ge衬底上外延生长中心波长为 85 0nm的Bragg结构 ,测得的反射谱与理论设计相吻合 ,X Ray双晶衍射测得的Bragg周期厚度为 1 1 0nm。制作出具有埋层Bragg结构的GaAs/Ge太阳电池。对整个电池吸收系数的测试结果表明具有埋层Bragg结构的太阳电池的吸收系数低于无Bragg结构的电池。AM 1 .5光谱下电池I V曲线测试结果为 :Voc=1 .0 33V ,Jsc=2 6 .0 4mA/cm2 ,FF =82 .5 2 % ,η =2 2 .2 % ,对电池性能作了初步研究     

InGaAs angled-grating distributed Bragg reflector lasers integrated with grating outcoupler for collimation

An angled-grating distributed Bragg reflector (DBR) laser integrated with a grating outcoupler (GO) is proposed and demonstrated. It consists of an angled broad-area gain stripe surrounded by angled DBR (/spl alpha/-DBR) gratings parallel to the gain stripe and two DBR gratings for feedback at the stripe ends, and a GO for emitting a collimated output beam. Due to distributed Bragg reflection in the /spl alpha/-DBR gratings, filamentation can be suppressed. Single-mode lasing up to 69 mW peak power was obtained under pulse condition. A collimated output beam with divergence angles, close to the diffraction limit, was obtained. These results confirm the effectiveness of the /spl alpha/-DBR gratings.     

Theory of design parameters for quasi-phase-matched waveguides andapplication to frequency doubling in polymer waveguides

A theory of dispersion in single-mode symmetric waveguides is presented for phase-matching second harmonic generation (SHG) of the fundamental modes, based on the approximate analytical waveguide theory of Botez. The theory is used to derive new equations for the maximum phase-matching distance allowed when there are random fluctuations in waveguide thicknesses, under critical and noncritical phase-matching conditions. The theory is also used to calculate the overlap integral as a function of the waveguide parameters V^ω and V^2ω. A new expression is derived for the efficiency of SHG in waveguides in terms of waveguide parameters that can be used to optimize SHG. Theoretical results are presented for typical LiNbO₃ and polymer waveguides. Quasi-phase-matched (QPM) waveguides are fabricated from nonlinear optical (NLO) polymers using the techniques of periodic poling and bleaching, and channel waveguides are printed by the bleaching of the NLO polymers. The NLO polymers are characterized for their refractive indexes, optical loss, NLO coefficients, and bleaching characteristics. Phase-matched SHG results are presented for the different fabrication methods over a distance of 0.5 cm, and an assessment is given of the relative strengths and weaknesses of the different fabrication approaches     

热电能量采集自适应阻抗匹配电路设计

为了实现自供电的无线网络节点,本文提出了基于MSP430的低功耗自适应阻抗匹配设计方案。为了降低阻抗匹配电路的功率消耗,方案使用MSP430产生、调节PWM波的参数控制MOS开关产生虚拟阻抗,以实现最大功率跟踪。使用MSP430内部AD模块实时测量电路参数,使用扰动观察法进行反馈调节。设计实验获得了输出功率与PWM波占空比之间的关系,并在变温度条件下测试了方案的工作性能。实验表明本文提出的控制方案可以实现自供电稳定工作,并且可以大幅提高能量收集的效率和输出功率。     

A design method for robust model matching control of nonminimum‐phase discrete‐time systems

This paper presents a design method for robust model matching control of nonminimum‐phase discrete‐time systems. This scheme can robustly control the nominal model in the presence of unmodeled dynamics and can achieve the desired model matching simultaneously. Furthermore, the sufficient condition for stabilizing the nominal model in the presence of the unmodeled dynamics is derived and the existence of bounds for all signals is proved. Finally, computer simulation results are presented to illustrate the effectiveness of the proposed method. © 1999 Scripta Technica, Electr Eng Jpn, 128(2): 36–44, 1999     

Formulating hybrid equations and state equations for nonlinear circuits using SPICE

Hybrid equations are often used in the theoretical study of nonlinear resistive circuits because they have an easy‐to‐analyze structure. They are also advantageous in the numerical analysis of nonlinear resistive circuits because they are separable and consist of a relatively small number of variables. However, the hybrid equations are seldom used in practical applications because their formulation is complicated. In this letter, we propose a simple method for formulating the hybrid equations using SPICE. In the proposed method, we only perform the transient analysis of SPICE on a linear circuit that is obtained through a small modification to the original circuit. It is also shown that state equations for nonlinear dynamic circuits can also be formulated by using the proposed method. Copyright © 2011 John Wiley & Sons, Ltd.     

The design of linear phase FIR filters using the IDFT

The paper presents a comprehensive set of equations for specifying the transfer function of linear phase finite-impulse response (LPFIR) filters. A procedure for designing the eight possible LPFIR filters (symmetric and anti-symmetric, even and odd length, type 1 and type 2 filters), using the inverse discrete Fourier transform (IDFT) is described. This technique can be equally applied to the window method and the frequency sampling method     

Low loss matching (LLM) design technique for power amplifiers

This paper describes a design methodology used for the development of multistage broadband power amplifiers. The method uses the measured small-signal S-parameters and loadpull data in association with low loss matching (LLM) design technique. The Q-point of the amplifier was selected for class-AB operation of the device in order to obtain the maximum power-added efficiency (PAE) and bandwidth. In the design optimization using loadline techniques, four sets of S-parameter data, corresponding to device low gain, high gain, low current, and high current, were used. These data files represent the possible fabrication changes and allow realization of a design more tolerant to process variations.     

纯电动大客车超级电容器参数匹配与实验

基于对超级电容器充放电效率和汽车行驶特性的分析,重点研究了超级电容器放电时间与其效率和汽车加速时间的匹配关系,以及根据其放电时间来确定其他参数的特殊设计规则。通过BFC 6100-EV电动大客车装车试验,表明所提出的匹配方法是可行的,超级电容器能有效地提高汽车动力性和制动能量回收,避免了动力电池组大电流放电。     

基于TCensus的立体匹配算法及FPGA设计

随着无人机技术的迅速发展,利用无人机代替人工进行电力线巡线是行业内发展的新趋势。尽管无人机电力巡线相对于人工巡检效率更高,更加安全,但无人机巡检仍然面临一些问题,无人机的避障技术亟待完善,在巡检过程中无人机会出现与周边障碍物相撞的情况,尤其是细小的电线对无人机安全造成巨大的威胁。这些线状物往往目标不明显,雷达,超声波等技术得到的回波较少,造成避障困难。基于双目视觉系统的无人机避障技术在无人机避障领域得到了广泛的研究和关注。针对双目视觉实时无人机电力巡检避障应用,提出了基于TCensus（形态学Tophat变换和MiniCensus）变换的匹配代价测量方法来对原始图像中的弱目标进行增强,同时采用基于十字结构的支持区域来提高匹配的准确度。实验证明,本文设计的双目视觉系统可以有效检测无人机到电力线之间的距离,检测误差达到5%,提出的TCensus立体匹配算法与其它方法相比除了能够获得同样准确的背景深度图之外,还能对电线区域具有更精细的成像效果。     

贯流式机组桨叶与导叶全三维匹配设计方法

本文建立了灯泡贯流式机组桨叶和与之相匹配的导叶的全三维反问题计算模型.模型中通过给定导叶出口边与桨叶进口边上的速度矩分布规律来建立桨叶和导叶之间的匹配关系.设计得到的桨叶和导叶叶型均为空间曲面形状,内缘比外缘更为扭曲.在设计工况对其进行联合数值模拟,并根据转轮进口和尾水管进口截面上的速度矩分布状况调整了设计,增大导叶的出口安放角,使得转轮效率提高到92.28%.该设计方法有利于研究桨叶和导叶之间的联合流动性能,为寻求其最佳匹配关系打下了基础.     

间接电流控制三相交—直变流器的系统分析与设计

性能完备的交-直变流器需要提供良好的功率因数,以及很低的电流谐波,同时要求能量回馈电网。PWM控制方式下的电压型变流器具有上述优点,在PAC(幅相控制)方式下的电压源变流器的综合研究,并给出实现的方案及试验结果。     

Analysis and design of current regulators using complex vectors

The analysis and design of current regulators for multiphase AC loads in AC machines is presented using complex vector notation. The use of complex vector notation provides a way of comparing the performance of controller topologies through their complex vector root locus and complex vector frequency-response functions. Limitations in the performance of the synchronous frame proportional plus integral current regulator are outlined and several ways of improving its performance are suggested and investigated     

Numerical analysis of waveguide bandpass filters using singular integral equations and construction of simple design formulas

A powerful numerical solution is presented for bandpass filters in rectangular waveguides. The filters are composed of cascading of perfectly conducting inductive obstacles with zero thickness: asymmetrical windows, symmetrical windows, or symmetrical strips. The problem is reduced to a set of singular integral equations, which is solved by an extension of Lewin's quasi‐static procedure. After the accuracy of the classical formulas for the equivalent reactance is investigated, the simple inverse formulas are constructed to yield proper window widths for desired equivalent parameters. Their effectiveness is demonstrated by designing practical filters having maximally flat or equal‐ripple characteristics. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 148(4): 17–25, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10251     

三相交流电压相位同步检测电路

介绍了用光耦器件与二极管构成的三相交流电压相位同步检测电路,它可替代笨重的变压器式检测相位方式,提高检测精度和稳定性,拓宽了同步范围,并实现了低成本、低能耗。     

电源控制器相地保护电路的独特设计

随着集成电路的飞速发展,短路保护电路变得越来越重要,特别是相地间的直接短路。介绍了一款投影机电源的相地短路保护,当出现短路现象时,该保护电路能够迅速切断电源,从而保护其他关键器件,比如电源管理芯片。使用一个电阻RSC检测相线L1中的电流,如果L1中电流超过了设定电流,该保护电路就会发挥作用,将IC PWM输出关闭。设定电流为额定输入电压时工作时电流的3倍,这等于给电气产品短路保护方面上了双保险。使用Pspice软件对设计电路进行了仿真,结果显示本设计达到了预定目的。     

用于反窃电的实时相量测量算法及装置硬件设计

相量的准确测量可为电力部门提供电网准确动态数据,通过分析电网中不同地点、不同时刻的相量,可以发现窃电行为.提出双谱线对称插值FFT相量测量算法,给出了用于反窃电的实时相量测量装置硬件设计方案.论文详细介绍了信号调理与采集模块、数据处理模块、通信模块的设计原理,最后给出了仿真和测量结果.     

The phase reversal effect of a fiber Bragg grating and its application to optical switches

We propose an interferometer‐type multistate optical switch and an interferometer‐type digital performance switch using a fiber Bragg grating (FBG) and the phase reversal effect. The effect is a reversing phenomenon of optical phase difference between the reflected and transmitted light from an FBG on a reflectivity spectrum dip between the main reflection band and first sideband. By combining this effect and reflectivity change, the multistate switch including only a single FBG can perform as a four‐state switch. In this paper we describe the principle of the phase reversal effect and some novel optical switch structures, and also the results of experimental examination. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(3): 38–48, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10136     

Analysis and design of LC oscillators associated with frequency multipliers: a phase noise perspective

When a local oscillator signal generation system is based on an LC oscillator and a frequency multiplier, the question of determining the optimal multiplication factor is a key issue. In this paper, the problem is addressed in order to minimize the 1/f ² phase noise within a tuning range constraint. The analysis, with a practical graphical representation, reveals the oscillator phase noise dependence on the oscillating frequency in the transition from two different regimes, named the inductor‐limited quality factor and the capacitor‐limited quality factor. The results obtained enable the evaluation of the phase noise performance of systems based on a sub‐harmonic and super‐harmonic oscillators and how they compare with an oscillator in the fundamental mode. Crucial questions like the phase noise improvement that these systems can achieve are analytically answered. A design methodology is thus proposed and verified through measurements on a frequency source at 31 GHz, composed by a sub‐harmonic voltage‐controlled oscillator followed by an injection‐locked frequency tripler, dedicated to backhauling applications, designed on a BiCMOS process technology. The tuning range is 10%, and the phase noise at a 1‐MHz offset is −112 dBc/Hz. Copyright © 2017 John Wiley & Sons, Ltd.