Low‐power,latch‐based multistage time‐to‐digital converter in 65 nm CMOS technology

In this paper, a low‐power and high‐resolution latch‐based time‐to‐digital converter (TDC) based on a multistage scheme is proposed. The proposed multistage TDC includes coarse, middle, and fine stages. The coarse stage is a new design of the flash TDC that is implemented by latches without using the delay cell. Also, the middle stage is a new design of the Vernier TDC with employed latches. The fine stage comprises parallel latches with different input loads.     

TDI CCD相机大姿态角推扫成像行频精确匹配

针对大视场TDI CCD相机大姿态角推扫成像过程中像面上像点像速差异较大,行频匹配精度不高引起的相机传函下降等问题,提出一种可支持粗调和精调的高精度行频匹配方法。首先,阐述了大视场遥感相机像速场的主要特点及像速匹配的关键问题;其次,深入分析了大视场TDI CCD相机大角度侧摆和前后摆推扫成像的像速场特性;然后,根据像速场特性制定同速匹配模式和异速匹配模式,分析传函特性,确定各自模式的使用条件;最后,提出了一种可支持粗调和精调的高精度行频匹配方法,并分析已实现行频匹配方法的精度,最终满足给定行频匹配精度要求。实验结果表明：在积分级数为96级,粗调方法使行频精度达到0．999425,精调方法使行频精度达到0．999928,2种方法均能使相机传函MTF优于0．998,从而实现大视场TDI CCD相机在各种大姿态角推扫成像条件下高质量成像。     

A Technique of Automatically Tuning Decision Parameters for Rule‐Based Defect Classifier

In automatic defect classification of semiconductor wafers using scanning electron microscope images, we propose a technique of tuning decision parameters for rule‐based defect classifiers. The proposed method adopts a coarse‐to‐fine search for reduction in processing time. However, due to search leakage, there is no guarantee that the same solutions as in a full parameter search can be obtained. In order to prevent leakage in the coarse search theoretically, the proposed method evaluates a candidate parameter set based on the estimated range of classification accuracy attained by not only the candidate but the surrounding solutions eliminated by the coarse search. Experiments on real image data demonstrate the effectiveness of the proposed method. The proposed method can extract the same solutions as the full parameter search within almost the same processing time as the conventional coarse‐to‐fine search. When the sampling step of the coarse search is three to six, while the tuning time of the conventional coarse‐to‐fine search is 1 to 21 s, that of the proposed method is 5 to 35 s.     

Control schemes and transient characteristics of a high‐speed phase shifter for power flow control in power transmission systems

In recent years, attention has been paid to the concept of FACTS (Flexible AC Transmission Systems), along with significant progress in power electronic technology. A high‐speed phase shifter, which is one of the most promising devices in the FACTS concept, has the potential of power flow control and/or voltage stability in power transmission systems. In this paper, theory and experiment reveal that conventional high‐speed phase shifters may cause power swings in a transient state as a result of coupling between instantaneous active and reactive power control loops. Thus, two new control schemes for a high‐speed phase shifter are proposed to achieve both power flow control and power swing damping. The second proposed control scheme is based on the control scheme of an already proposed series active filter. Simulated and experimental results agree well with analytical results, not only in steady states but also in transient states. © 1999 Scripta Technica, Electr Eng Jpn, 128(2): 74–82, 1999     

高精度永磁交流伺服系统及其转速特性分析

以PWM控制为核心的全数字永磁交流伺服系统成为伺服系统的主要发展方向。但是在某些低电压、低转速、高精度的应用场合,采用线性放大方式更为适合。和PWM控制方式相比,这种方法的定子电流谐波小,跟踪精度高。文章介绍了一种采用TMS320F240为核心的线性放大永磁交流伺服系统,研究了其控制环路和转速特性问题,给出了实验结果。表明实际效果良好。     

多电机同步控制在升降舞台系统中的应用

以四台电动机分别拖动四个升降舞台为研究背景,分析了在实际工程中造成多个升降舞台运行不同步的主要因素以及传动装置中的齿隙对升降舞台启动过程的影响,提出了在速度并联同步控制的基础上引入位置输出耦合补偿控制来实现剧场中多个升降舞台的混合同步控制,同时给出一个满足不同升降舞台工程的同步误差评价函数。仿真结果与工程应用均表明,这种方法很好的实现了多台电机的高精度同步控制。     

永磁同步直线电动机径向基神经网络PID控制

针对永磁同步直线电动机的初级磁链近似为常数这一特点,在d-q轴下建立了直线电动机的数学模型。直线电动机具有非线性、耦合性、负载扰动、时变不确定性等特点。常规PID控制虽然结构简单、输出稳定、易实现,但在高速高精度应用场合却不能达到理想的控制效果。提出了一种基于RBF神经网络与传统PID控制相结合的新策略,形成RBF神经网络整定PID控制,在一定程度上改进了PID控制性能。仿真结果表明,RBF神经网络PID控制具有更好的动态响应性和更加稳定的跟踪性能。     

Stochastic high‐order internal model‐based adaptive TILC with random uncertainties in initial states and desired reference points

Many practical batch processes operate repetitively in industry and lack intermediate measurements for the interested process variables. Moreover, the initial states as well as the desired product objective often vary with different runs because of the existence of many uncertainties in practice. This work proposes a novel adaptive terminal iterative learning control method to deal with random uncertainties in desired terminal points and initial states. The run‐varying initial states are formulated by a stochastic high‐order internal model, which is further incorporated into the controller design. The desired terminal output is run dependent and is directly compensated like a feedback term in the controller. Only the system output at the endpoint of an operation is utilized to update the control signal. An estimation algorithm is designed to update the system Markov parameters as a whole. No explicit model information is involved in the controller design; thus, the proposed method is data driven and can be applied to nonlinear systems directly. Both the theoretical analysis and the simulation studies demonstrate the effectiveness of the proposed approach under random initial states and iteration‐varying referenced terminal points. Copyright © 2016 John Wiley & Sons, Ltd.     

全功率变流器可变速抽水蓄能机组的功率调节特性分析

全功率变流器（full size converter, FSC）可变速抽水蓄能技术是控制电网负荷频率,平衡可再生能源发电波动的有效手段。在介绍三电平FSC可变速抽水蓄能机组整体结构的基础上,给出了机侧变流器和网侧变流器的模型和控制策略。在确定由于电网需求而产生的参考功率的基础上,提出了FSC可变速抽水蓄能机组在发电模式和电动模式时有功功率和无功功率的控制策略。针对所建立的FSC可变速抽水蓄能机组模型,采用冲击响应傅立叶变换法,给出了机组的频谱特性,对照风电波动频谱特性,阐述了全功率机组对可再生能源引起的电网波动控制的有效性。最后对抽水蓄能机组在抑制风电出力波动中的作用进行了仿真验证。     

基于FPGA的精密时间测量系统设计

设计了一种在FPGA中基于时间内插技术而实现的高精度时间测量系统。在分析传统数字计数法原理与误差的基础上,从误差源头出发,为精确测量“细”时间即传统数字计数法中待测信号上升沿与下一个计数时钟上升沿的时间差,提出用4个同频、相位依次相差45°的内插时钟测量,通过待测信号上升沿锁存4个内插时钟状态来估算这部分时间差。“粗”时间用高速时钟直接计数,可以保证有大的测量量程,详细分析了该方法测量原理误差。通过实验验证表明,精度高达312.5 ps,误差小于300 ps,该设计具有测量范围大、测量精度高、占用资源少、体积小等优点。     

轴角编码单元在CINRAD/SA雷达中的应用

介绍了我国新一代天气雷达CINRAD／SA天线伺服系统轴角编码单元的主要功能以及逻辑电路结构,分析了旋变激磁信号发生器、旋转变压器、RDC模数变换模块、PLD可编程逻辑器等关键部件的具体功能。进一步深入剖析了轴角编码单元如何利用粗、精码合成与纠错程序控制策略实现雷达天线的高精度控制。最后,总结分析了其在新一代天气雷达工程中的实际应用效果,证明轴角编码单元的工作性能充分达到了预期的技术指标。旨在为各级气象雷达技术保障人员提供CINRAD／SA雷达伺服系统维护和研究方面的参考。     

步进电机伺服系统在XK5040数控立式铣床中的应用

在开环数控机床中,由于计算机的速度和精度都很高,完全能满足数控机床高速度、高精度的要求;因而数控机床的精度和速度等全取决于步进电机的伺服系统性能。当选择和应用合适的步进电机伺服系统,可满足一般数控铣床速度和精度的要求。同时介绍了XK5040数控立式铣床的功能及主要参数和其伺服驱动系统特点。     

A new position‐sensorless position control method for high‐speed spindle systems

This paper proposes a new position‐sensorless position control method for high‐speed spindle drive systems. Mechanical vulnerability of position sensors such as an encoder mounted on a spindle motor is becoming a serious problem as required speed increases. For high speeds above 1500 rad/s, sensorless drive is preferred. It is possible for current technologies to control spindle motor in speed control mode without the sensor, but not in position control mode without the sensor. In the example of high‐speed spindle systems of automatic machine tools, implements must be automatically attached to and removed from the spindle at standstill. Automation necessitates position control, for which current technologies require a sensor. The proposed method makes it possible to realize pure sensorless high‐speed spindle systems performing in both speed and a position control modes. The method can attain a position control performance with quick settling from speed control and a repetitive positioning precision of 0.006 rad, 0.4°, which is comparable to that achieved by current sensor‐based methods. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(3): 58–69, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10059     

双馈电机系统滑模变结构反演控制的研究

应用滑模变结构理论和反演控制方法设计了双馈感应电机的非线性控制器.该控制器结合反演法的动、静特性优良和滑模变结构控制鲁棒性强的优点,可以良好地实现电机转速的跟踪控制.针对电机转矩给定控制,提出了一种复合控制算法,有效地提高了系统动态性能和静态精度.对于所提出的控制策略予以详细推导,并在Matlab/simulink环境下进行了仿真试验.仿真结果表明,该控制策略能够实现双馈电机转速的有效跟踪,系统具有良好的动、静态性能和较强的鲁棒性.     

常见傅里叶变换的滤波性能分析

为选取一种满足继电保护可靠性和灵敏度要求的滤波算法,对傅里叶变换算法的2种常见改进算法——差分算法和补偿算法进行分析。研究当输入模拟信号叠加谐波和衰减直流分量时,在不同的采样频率下,这2种改进算法的性能和效率。衰减直流分量实时补偿的算法精度较高,但计算量过大。差分算法能在计算量增加不大的情况下,大幅度地提高滤波精度。通过MathCAD仿真计算,分析上述变换的误差,并对比采用全周和半周不同数据窗造成的差异。在一周期24点采样时,即可达到精度和速度的最优效果。考虑兼顾保护的动作速度和测量精度,可以在故障初期采用半周数据窗的傅里叶算法为保护提供数据,后期改用全周数据窗算法。     

感应线圈弹射器端板对性能的影响分析

感应线圈弹射器的驱动线圈采用脉冲电源供电,放电瞬间电枢产生大推力加速到极高的速度,同时驱动线圈两端的支撑端板将承受很大的轴向反作用力,在实际工程中其采用高强度的Q345材料,设计上不仅需要关注机械强度,还需要关注对弹射性能的影响,影响因数主要是安装位置。本文基于Maxwell二维瞬态仿真模型,仿真分析了支撑端板位置对线圈弹射器性能的影响,然后设计完成了单级线圈弹射器并进行试验,试验与仿真结果相吻合。结果表明：支撑端板距离驱动线圈铜导线越远,影响越小,弹射器的发射效率越高。对于文中模型,两者之间距离s超过0.654倍的线圈内径,该影响可忽略。     

双级矩阵变换器的过调制策略

针对双级矩阵变换器常规调制策略电压传输比低的问题,在不改变双级矩阵变换器拓扑结构的前提下,该文提出了一种可以提高电压传输比的双级矩阵变换器调制策略。该调制策略将双级矩阵变换器分为两级控制：整流级采用常规电流空间矢量合成法;逆变级根据电压传输比的不同要求将电压空间矢量调制区域分为线性调制区和过调制区。根据过调制程度要求的不同,又将过调制区域分为过调制区域Ⅰ和过调制区域Ⅱ,各个区域分别采用不同的调制模式控制逆变级的输出。论文从理论上分析了过调制策略的原理。仿真和实验结果表明, 双级矩阵变换器过调制时输出电压基波可以精确控制,谐波畸变率比较小,输入输出电流波形质量好。     

基于TSMC永磁方波电机转矩脉动抑制的研究

针对电机换相时转矩脉动过大的问题,提出一种新颖的基于双级矩阵变换器的永磁方波电动机的拓扑结构,在该拓扑结构上采用电流和转速的双闭环控制,通过检测定子端电压来确定续流时间,改进了续流时期 PWM调制策略,所提出PWM调制策略无论在低速还是高速,都能准确确定电机续流时间,快速抑制转矩脉动,实现对永磁方波电动机的交-交直接控制,该控制策略使得输入功率因数接近1,同时能够实现能量双向流动。通过 MATLAB 仿真结果表明电机输出电流接近矩形波,换向转矩脉动得到很好的抑制,转速跟踪准确,验证了所提控制策略的正确性和有效性。     

特约文章：三峡水库下游河床冲刷与水位变化

为探析三峡水库下游河床冲淤与水沙输移之间的关系以及河床冲淤对洪枯水位的影响,采用三峡水库运用前后长江中下游水文泥沙和河道地形资料,分析归纳了主要水文站水沙变化、沿程河道冲淤分布和洪枯水位变化特征。研究表明：冲刷集中于枯水河槽既与洪水频次减少、中等流量持续时间加长有关,也与中等流量下河道冲刷率大、洪水流量下河道冲刷率小的特点有关;主冲刷带自上而下推移,目前仍位于荆江河段;粗沙（d > 0.125 mm）的年均输移量至监利基本可恢复至蓄水前的多年均值,城陵矶以下长河段冲刷主要是细颗粒冲刷导致;河道冲刷导致中枯水位明显下降,并在城陵矶以上沙质河段呈现加速下降趋势,但当流量大于平滩流量附近的临界值时,高水位变化不大,初步预估这种变化特点将在较长时期内保持。     

Converter Using SiC‐MOSFET for Ultra‐High‐Speed Elevator

In this study, we developed a converter based on SiC (Silicon Carbide)‐MOSFET for use in ultra‐high‐speed elevators, with a reduced volume of 15% compared with the conventional converter. We succeeded in reducing the power loss of the converter unit by 56% compared to the conventional converter in one round trip under high temperature condition. Recently, because of their useful characteristics, wide‐gap semiconductors, such as SiC and GaN, have gained considerable attention for use in various applications in the power electronics systems. Therefore, we studied the use of a converter in elevator systems based on SiC‐MOSFET. We used a 1200 V/800 A SiC‐MOSFET module for the converter unit. We developed a prototype of the converter unit and the control panel by applying for the SiC‐MOSFET module for an ultra‐high‐speed elevator. As a result, the setting area of the control panel (main part) becomes less than 43% of the conventional panel. We tried to demonstrate the working of a 68‐kW elevator by applying the prototype control panel. Because of the characteristic of the switching loss of SiC‐MOSFET, the power loss of the converter unit has almost no dependence on temperature. An energy‐saving effect of approximately 17% was achieved in the total elevator system in one round trip under high‐temperature condition.