19 resultados para PWM controller

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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For a class of nonlinear dynamical systems, the adaptive controllers are investigated using direction basis function (DBF) in this paper. Based on the criterion of Lyapunov' stability, DBF is designed which guarantees that the output of the controlled system asymptotically tracks the reference signals. Finally, the simulation shows the good tracking effectiveness of the adaptive controller.

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A quantum well controller (QWC) consisting of a direct-gap/indirect-gap quantum well and a doping interface is proposed to control the dynamic operation of the Gunn active layer. Through the Monte Carlo simulation a new relaxation mode for this new device is found. The oscillation and amplification behavior of the Gunn active layer under the control of the QWC is investigated theoretically and experimentally. All work demonstrates the great control capacity of the QWC and provides a new way to improve the performance of semiconductor devices. A new oscillation diode made of the QWC and a Gunn active layer has been designed and fabricated. In the 8 mm band the highest pulse output power of these diodes is 2.55 W and the highest conversion efficiency is 18%.

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LTC1629是Linear公司专门为低压大电流的DC-DC变换电路设计的PWM控制电路,应用该公司的PolyPhaseTM~(TM)技术,有效地减少了输入输出纹波电流,同时提高了变换器的效率。本文介绍它的基本组成部分的功能和简单应用电路。

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介绍了在CSR同步加速器高频控制系统改进项目中,高频前端控制器的改进设计。根据系统改进的具体要求,采用DSP+FPGA双电路板的体系结构,对高频前端控制器各个部分做了详细的设计,并给出了具体的资源消耗结果和设计图。

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介绍了国家重大科学工程项目——兰州重离子加速器冷却存储环(HIRFL-CSR)的实验环(CSRe)团簇内靶温度闭环控制器的设计。该控制器给气体喷嘴处测温电阻提供长时间稳定度为0.1%的1mA恒定电流,通过12位ADC得到喷嘴温度,并通过混合信号处理器MSP430F149来实现制冷/加热闭环操作。在多种不同实验气体的情况下,该控制器的温度控制精度小于0.5K。目前,该控制器在现场工作良好。

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HIRFL-CSR(Heavy Ion Research Facility at LanZhou-Cooling Storage Ring兰州重离子冷却储存环)是国家重大科学工程,其控制系统是一个庞大的系统,由许多分控制系统组成,磁场电源控制系统是CSR控制系统中很重要的一部分。加速器运行的所有过程都为电源所控制,所以我们的控制系统的直接控制对象就是磁场电源。为了保证CSR正常运行,控制过程波形的跟踪精度、速度和稳定度,是数字电源调节器的关键所在。电源控制系统以嵌入式处理器ARM、现场可编程门阵列FPGA为核心,实现了远程数据采集、网络通讯和自动控制等功能。本系统可以进行现场监控与调试,也可以通过集成的100Mbps以太网接口电路进行远程监测与控制,CSR上各处输出电压值和电源运行状态自动传送到中央控制中心,中控中心也可以发送命令查询当前电源设备状态和各种读数。本文主要介绍了基于ARM和FPGA的嵌入式电源控制系统的设计与实现。内容主要包括:(1)系统各部分硬件电路设计与电源控制功能实现 ,硬件系统调试 。(2)装载嵌入式Linux操作系统,测试平台接口信号,通过FPGA生成多路数字PWM波形。本文目的是解决CSR电源控制系统问题,但对于许多远程数据采集与控制等问题的解决有重要参考价值

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本文分析了三相电压型PWM整流器在abc、DQ、dq坐标系下的数学模型,开发了基于MATLAB/SIMULINK的三相PWM整流器仿真模块,仿真结果表明基于dq同步旋转坐标系的整流器数学模型是正确的,并具有独特优点。对常用空间电压矢量控制策略进行分析,给出了合成电压矢量的不同方法;分析了固定开关频率的电流预测控制原理。分析了电流环的控制策略,推导出电流环和电压环PI参数与整流器主电路各参数之间的关系。设计了双闭环控制PWM整流器系统的硬件、软件,实现解藕整流器输入电流,并完成了系统仿真,仿真结果表明电压和电流双闭环P1参数选择的合理性以及整个系统的可行性。

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提出了一种新的最优模糊PID控制器,它由两部分组成,即在线模糊推理机构和带有不完全微分的常规PID控制器,在模糊推理机构中,引入了三个可调节因子xp,xi和xd,其作用是进一步修改和优化模糊推理的结果,以使控制器对一个给定对象具有最优的控制效果,可调节因子的最优值采用ITAE准则及Nelder和Mead提出的柔性多面体最优搜索算法加以确定,这种PID控制器被用来控制由作者设计的智能人工腿中的一个直流电机,仿真结果表明该控制器的设计是非常有效的,它可被用于控制各种不同的对象和过程。

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为了实现水下机器人(UUV,Unmanned Underwater Vehicle)的高精度控制,深入研究了螺旋桨驱动UUV推进系统各个环节运行机理,并建立了它们各自的数学模型,包括PWM模块、直流永磁电机、螺旋桨、舵的数学模型。多功能仿真试验和湖试试验的系统响应曲线基本吻合,一方面表明本文建立的推进系统模型的正确性,另一方面体现了在多功能仿真平台上调试的控制策略和控制器参数具有很大的可信度。

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本文介绍了一种利用 PWM方式进行模拟量长线传送的应用,突出了它的结构简单、抗干扰能力强的优点。

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Microsensors and microactuators are vital organs of microelectromechanical systems (MEMS), forming the interfaces between controller and environment. They are usually used for devices ranging in size at sub-millimeter or micrometer level, transforming energy between two or more domains. Presently, most of the materials used in MEMS devices belong to the silicon material system, which is the basis of the integrated circuit industry. However, new techniques are being explored and developed, and the opportunities for MEMS materials selection are getting broader. The present paper tries to apply 'performance index' to select the material best suited to a given application, in the early stage of MEMS design. The selection is based on matching performance characteristics to the requirements. A series of performance indices are given to allow a wide range comparison of materials for several typical sensing and actuating structures, and a rapid identification of candidates for a given task. (C) 2002 Elsevier Science Ltd. All rights reserved.

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This paper considers the chaos synchronization of the modified Chua's circuit with x vertical bar x vertical bar function. We firstly show that a couple of the modified Chua systems with different parameters and initial conditions can be synchronized using active control when the values of parameters both in drive system and response system are known aforehand. Furthermore, based on Lyapunov stability theory we propose an adaptive active control approach to make the states of two identical Chua systems with unknown constant parameters asymptotically synchronized. Moreover the designed controller is independent of those unknown parameters. Numerical simulations are given to validate the proposed synchronization approach.

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提出一种用于一般广义离散系统的严格真动态输出反馈H_∞控制器设计方法。首先,构造辅助广义离散系统,给出该系统的状态反馈H_∞控制器设计方法,在此基础上,用两组矩阵不等式给出使一般广义离散系统是允许的且满足H_∞范数限制的控制器存在的充分条件,并给出了控制器的解析表达式。通过解这两组矩阵不等式,即可获得所需的控制器。控制器的可解性条件由系统的系数矩阵表达,因此不需要矩阵分解,可避免由矩阵分解产生的数值问题。仿真结果证实算法的有效性。