一种高效的二维恒虚警率处理方法

目标探测是雷达的一项重要功能,由于杂波和噪声一般在目标回波的距离和多普勒维同时存在,如果只使用一维恒虚警率检测将会降低探测性能,因此需要二维恒虚警率进行目标检测。传统的二维恒虚警率检测会使计算量大大增加,影响目标探测的实时性。改进的二维恒虚警率检测方法可极大减少检测单元,从而缩短了目标检测时间,并经过了工程验证。     

盲恒模均衡算法的比较分析和改进

首先介绍了一种针对单输入多输出(SIMO)通信接收系统模型的盲均衡算法,即分数间隔恒模算法(FSE-CMA)。并重点针对该算法的缺点进行了改进,给出了另两种新的改进型FSE-CMA算法,即SE-CMA算法和DSE-CMA算法。通过仿真实验比较了这三种算法的性能,得出了DSE-CMA算法比FSE-CMA算法和SE-CMA算法有不同程度改进的结论,表明了这种恒模算法更有利于实际应用。     

EFDA泵浦源半导体激光器驱动电源的设计

设计了一种EFDA泵浦源半导体激光器的驱动电源,采用由PC机和单片机构成的上下位机的控制结构,具有恒定功率和恒定电流两种控制模式.该驱动电源具有激光器保护电路,电流精度和光功率控制精度分别为0.15％和0.2％.     

基于恒模准则的盲均衡算法仿真

阐述了用于信道盲均衡的恒模算法的数学模型和基本原理。针对恒模算法存在收敛速度慢和相位旋转等不足,对近年来出现的一些性能优良的基于恒模准则的盲均衡算法——变步长恒模算法、修正恒模算法和多模算法进行了分析与仿真,并对各种改进算法在不同调制方式下的优缺点进行了说明。最后得到不同算法均衡后的星座图和均方误差曲线,表明具有较好的均衡效果。     

恒流器件及其在通信电源中妙用

一、概述 电压与电流都是基本的物理量。稳压源和恒流源均为稳定电源的重要分支,在仪器仪表、电子设备及高新科学技术中,均占有重要地位。然而,长期以来,人们更多地致力于对稳压源的研究,在不少应该采用恒流源供电的场所,仍不适当地使用了稳压源。其实,恒流源在许多方面比稳压源更行之有效,例如,各类传感器的恒流源供电,有线通信的远供电源等等。 在半导体领域中,能得到恒定电流的器件有很多,如镇流管、电子管、双极型晶体管、场效应晶体管、运算放大器、集成稳压器等,本文主要介绍专用恒流器件——恒流二极管及其在通信电源设计中的应用。     

丹佛斯同步卡在冷轧堆卷上的应用

介绍冷轧堆卷装置的组成和控制原理,利用丹佛斯同步同位卡的优异的电机轴特性的控制对冷轧堆卷进行恒线速、恒张力控制。很好的满足了在大卷径比（满轴和空轴的直径比在6-20倍）收放卷应用下的恒张力控制的要求。     

线性约束差分恒模自适应阵列性能分析

线性约束差分恒模算法(LCDCM)能有效克服恒模算法(CMA)中存在的干扰捕获问题,但其性能受迭代步长的影响。本文对所需信号功率、干扰信号功率及所需信号和干扰信号空域相关系数对迭代步长取值和算法收敛速度的影响进行了分析,给出了保证算法收敛的迭代步长的取值范围。最后利用计算机仿真对上述理论结果进行了验证。     

直流电子负载的设计

系统主要以STC89C52单片机为控制核心:设计恒流、恒压和恒阻方式由手动切换的电子负载,实现电源的可靠检测和带载能力。包括控制电路、主电路、采样电路、显示电路等;能够检测被检测电源的电流值、电压值、电阻值,并且实现过载保护,在液晶上显示各个参数的功能。     

基于子空间的线性约束最小二乘恒模算法

线性约束最小二乘恒模算法能够有效克服恒模算法中存在的干扰捕获问题,然而,在实际的系统中,由于受到来自噪声子空间分量的影响,从而导致性能下降。针对这一问题,该文提出了一种基于子空间方法的线性约束最小二乘恒模(SLSCM)多用户检测算法并对其性能进行了理论分析。该算法收敛速度快,信道跟踪能力强,有较好的输出信干噪比和误码率性能。理论分析和仿真实验验证了该文算法的有效性和优越性。     

一种新的变步长快速盲均衡算法

在无线通信信道中,码间干扰严重影响了通信的质量和可靠性。传统的自适应均衡算法需要训练序列降低了传输效率,恒模算法（CMA）可以很好的克服了这个问题。针对CMA算法收敛速度较慢和无法纠正相位误差的缺点,提出一种新的步长迭代方法的改进型恒模算法（NSMCMA）。蒙特卡罗仿真表明,提出的算法,相比传统CMA算法,不仅可以纠正信道的相位偏转,而且具有更好的均衡效果和收敛性能。     

A new method of rotor resistance estimation for vector-controlledinduction machines

The estimation of rotor time constant, or rotor resistance, in a vector-controlled induction machine is necessary to achieve high-performance torque control. A new method of estimating the rotor resistance online, for use in a vector-controlled induction machine, is presented. It uses short duration pulses added to the constant flux reference current i_dse* and based on the resultant torque command current produced by a proportional-integral controller i_qse * adjusts the rotor resistance estimate. This method of self-tuning the vector controller to the rotor time constant, when operating in a closed-loop speed control loop, does not produce torque pulsations when correctly tuned. In comparison to other online methods such as the extended Kalman filter and the extended Luenberger observer, this method does not require voltage sensors and is computationally simpler. The rotor resistance estimation technique is illustrated through simulation and practical implementation of a vector-controlled induction machine     

台达整体解决方案在圆网印花机系统的应用

本文主要介绍基于台达自动化产品的圆网印花机整体系统解决方案。台达圆网印花机整体系统解决方案,主要通过工业控制网络DeviceNet实现各色系的I／0控制;通过CANopen实现伺服数据的读写;同时通过独有的脉冲By—Pass功能实现12色伺服的同步控制。经现场实际生产验证,台达完善的工业控制网络,尤其是伺服内建独特动态...     

配料电气系统自动化改造

分析烧结机配料系统存在的问题,通过采用先进的PLC控制技术对自控系统升级改造,达到了对烧结机配料系统精度和稳定性。     

Estimation of induction machine inverse rotor time constant using torque angle tangent calculation

A new inverse rotor time constant estimation scheme for an induction machine is presented. For high performance induction machine control, indirect rotor flux oriented vector control is the most commonly applied control technique. It requires that an accurate estimate of the inverse rotor time constant is obtained to ensure correct orientation of the current vector with the rotor flux vector. An incorrect estimate will result in an incorrect flux level, reduced dynamic torque performance and reduced maximum available torque. A novel parameter estimation scheme is presented, based on the calculation of the tangent of the torque angle. The effectiveness of the technique is demonstrated through simulation and practical results.     

Variable flux control of permanent magnet synchronous motor drivesfor constant torque operation

In this paper, a small signal model of permanent magnet synchronous machines is developed which includes both components of torque, i.e., magnet torque and reluctance torque. The effects of flux variations on the torque are analyzed by the use of the developed model. The off-line torque compensation method proposed for induction machines is then adapted to permanent magnet motor drives to achieve a constant torque, variable flux operation of the drives. A sensitivity analysis is performed to show that the off-line method is influenced considerably by machine parameter variations. Therefore the concept of forced compensation is introduced and an on-line torque compensation controller is proposed. Simulation results are presented to show the effectiveness of the proposed controller. An experimental vector controlled permanent magnet motor drive including the on-line torque compensation controller is implemented based on a TMS320C31 DSP to evaluate the method. The experimental results also confirm a desirable variable flux control of the motor drive under constant torque operation     

变频器在塑料挤出机上的应用

本文介绍了塑料挤出机的工作过程以及张力控制的特点，并针对目前塑料挤出机张力控制存在的问题，提出了将变频调速技术应用于挤出机张力控制的方法。VACON变频器具有可编程功能，编程工具VACON NC1131-3 Engineering是一个符合IEC61131-3标准的图形化的编程工具，它可以用来设计VACON NX特殊的控制逻辑和参数。实践证明，VACON变频器可以实现塑料挤出机的恒张力控制，提高调速精度，降低成本，并且操作简单，运行稳定，具有很好的市场推广价值。     

高调光比发光二极管驱动控制器的设计与实现

This paper presents a high dimming ratio light emitting diode （LED） drive controller chip with digital mode dimming （DMD）. The chip is composed of a boost power converter and a dimming control block. A novel constant on time （COT） control strategy is proposed for boost converter to achieve high dimming ratio. In addition, a fast enough load transient response of the converter power stage ensures its high dimming ratio. The COT control circuit operates mainly based on two current-capacitor timers and a finite state machine （FSM）. The LED drive controller chip is designed and fabricated in 1.5μm bipolar CMOS-DMOS （BCD） process with a die area of 1.31 x 1.43 mm^2. Experimental results show that the proposed LED drive system works well. And, as expected, the minimum LED dimming on time of 1.0μs and the corresponding dimming ratio of 1000 ： 1 at 1 kHz dimming frequency are successfully achieved.     

Design and implementation of a high dimming ratio LED drive controller

This paper presents a high dimming ratio light emitting diode (LED) drive controller chip with digital mode dimming (DMD). The chip is composed of a boost power converter and a dimming control block. A novel constant on time (COT) control strategy is proposed for boost converter to achieve high dimming ratio. In addition, a fast enough load transient response of the converter power stage ensures its high dimming ratio. The COT control circuit operates mainly based on two current-capacitor timers and a finite state machine (FSM). The LED drive con-troller chip is designed and fabricated in 1.5μm bipolar CMOS-DMOS (BCD) process with a die area of 1.31 × 1.43 mm2. Experimental results show that the proposed LED drive system works well. And, as expected, the minimum LED dimming on time of 1.0μs and the corresponding dimming ratio of 1000 : 1 at 1 kHz dimming frequency are successfully achieved.     

高炉液压开口机通过变频器与PLC实现分段恒压运行

本文结合济钢第二炼铁厂1750m3高炉液压开口机的特点,通过与传统控制系统的对比,重点分析研究了液压开口机实施变频器与PLC相结合的自动控制系统,其分段恒压运行的功能实现节能降耗经济意义。     

Online identification of induction machine electrical parameters for vector control loop tuning

In a vector-controlled induction machine drive, accurate knowledge of the machine electrical parameters is required to ensure correct alignment of the stator current vector relative to the rotor flux vector, to decouple the fluxand torque-producing currents and to tune the current control loops. This paper presents a new method for online identification of the induction machine parameters required to tune a rotor-flux-oriented (RFO) vector control scheme. Accuracy of the slip frequency estimation required for RFO vector control is achieved by utilizing the parameter independent "flux pulse" rotor time constant estimation scheme, which utilizes short-duration pulses injected into the flux-producing current. The parameters required to tune the synchronous frame current control loops with a decoupling circuit are estimated using a recursive estimation scheme derived from the synchronous frame voltage equations. As the "flux pulse" scheme requires signal injection into the flux-producing current a new rotor time constant estimation scheme is presented, based on the sensitivity analysis of the recursive parameter estimation scheme. Simulation and experimental results are presented which demonstrate the effectiveness of the online parameter identification and control loop tuning technique.