PLC在一体化反应器污水处理系统中的应用

本文主要介绍PLC在污水处理系统的应用,着重介绍系统的三级安全控制模式和传感器控制、时序控制两种软件控制功能及其实现方法,时序控制则提供了一种新的控制方法。     

三菱Q系列PLC在洗煤厂的应用

一、系统设计思路根据洗煤厂上艺控制流程和实际要求，将系统分为三级控制具体技术思路如下。     

基于PID串级液位控制的MATLAB仿真系统

本文设计了基于PID串级液位控制的MATLAB仿真系统,利用自动控制技术,实现对三级水箱液位进行串级控制的仿真测试,并且建立三容水箱的模型,采用实验建模法求取模型的传递函数,通过MATLAB软件对PID串级液位控制过程进行仿真,验证了串级控制对提高系统性能的作用。     

炭素回转窑三级控制系统的设计

炭素回转窑具有时变性、大惯性和大滞后性等特点,目前常规的控制策略难以控制,提出炭素回转窑的三级控制系统方案。第一级检测系统扫描分析回转窑煅烧带的温度、位置和长度;第二级基础级自动控制系统基于模型预测控制方法,实现回转窑进料速度、窑尾温度和负压的多变量协调控制;第三级智能决策系统以Fuzzy CIips推理机为引擎,推理输出工况的故障分析和决策信息,实现可靠高效的回转窑燃烧控制,并最大限度地延长其使用寿命。     

大沈线管道工程SCADA系统的设计与应用

本文以大沈管道工程为例,讨论了SCADA系统在长输管线上的应用和控制模式。SCADA系统基于光缆和公网电路的通信方式,采用三级控制和管理模式,有效地实现了对管道的监控、调度和管理,保证管道的安全、平稳、自动化运行。     

HDLC协议在阀基控制通信中的应用

提出了采用高级数据链路控制(HDLC)作为换流阀系统中控制主机与阀基控制单元(VCU)之间通信协议的应用方式。该换流阀系统为三级控制系统,在控制主机和VCU上采用现场可编程逻辑阵列(FPGA)实现了HDLC收发器模块,外接光电转换器,采用光纤通信。其中控制主机通过HDLC协议向VCU发送脉冲宽度调制(PWM)控制命令和定值参数等数据,VCU则通过HDLC协议向控制主机上传电流电压采样值和阀状态信息等数据。通过实际系统的运行测试,验证了HDLC协议在控制主机与VCU之间通信的可靠性、实时性,并使系统具有较高的数据吞吐能力和灵活的可扩展性。     

三级倒立摆的加权变量模糊神经网络控制

为了提高三级倒立摆系统控制的响应速度和稳定性,在设计Mamdani型摸糊推理规则控制器控制倒立摆系统稳定的基础上,设计了一种更有效率的基于Sugeno型模糊推理规则的模糊神经网络控制器。该控制器使用BP神经网络和最小二乘法的混合算法进行参数训练,能够准确归纳输入输出量的模糊隶属度函数和模糊逻辑规则。通过与Mamdani型控制器的仿真对比,表明该Sugeno型模糊神经网络控制器对三级倒立摆系统的控制具有良好的稳定性和快速性,以及较高的控制精度。     

基于CAN总线的三级智能火灾报警系统

针对大、中型智能小区的火灾防范的要求,利用CAN总线,设计和开发了一种基于CAN总线的三级智能火灾报警系统.系统由用户端自动报警器、区域控制器、中央控制器和主控计算机四个部分组成,采用三级控制的方案,即采用两极CAN总线和一级RS-232总线作为通信网络.通过在虚拟住宅环境下测试,系统通信能力强,实时性好,高可靠性.同时该系统还具有便于联网以及便于扩展等优点.     

基于多Agent的微电网电压无功控制系统

将多Agent技术引入微电网的电压无功控制中,并给出了基于多Agent的三级电压无功控制系统结构,重点分析了微网级(二级)电压无功控制。受电气距离思想的启发,提出了以操作优劣距离最短来确定最优操作动作的控制策略。以IEEE—39系统为基础的仿真说明了多Agent电压无功控制对微电网系统的电压无功能起到良好的调节控制作用。     

油田原油深加工中多级分布式控制系统

主要阐述了某油田原油深加工多级分布式计算机控制系统的构成以及PLC组网通信、硬件配置和软件的设计。该系统有三级，其中每一级又呈分布式构成，协调控制级对整个公司的生产过程进行协调，递解控制级给定每一个被控量的设定值，由局部控制级进行具体的PID控制，并且从中间一级可以看到控制过程的实时数据和历史数据，从而可以及时调整参数达到最优控制。     

汽包三冲量水位控制及其应用

以三冲量串级汽包水位控制系统为例,介绍锅炉汽包水位的动态特性、控制任务和控制方案,以及串级三冲量汽包水位控制系统的参数整定。     

基于MMC的轻型高压直流输电系统的建模与控制

针对基于电压源变换器VSC的高压直流HVDC输电系统存在输出电压低次谐波含量多、需要体积庞大的滤波器和变压器、串联器件的动态均压等问题,提出了一种基于模块化多电平变换器MMC的轻型HVDC输电系统的设计方案;根据建立的MMC-HDVC输电系统的数学模型,详细介绍了该系统控制策略的实现。该控制策略从装置级和系统级两个方面控制MMC-HVDC输电系统,分别实现子模块电容电压的平衡控制及系统的功率解耦控制。仿真结果验证了该系统的可行性与有效性。     

Distributed Control of Multiple-Bus Microgrid With Paralleled Distributed Generators

A microgrid is hard to control due to its reduced inertia and increased uncertainties. To overcome the challenges of microgrid control, advanced controllers need to be developed. In this paper, a distributed, two-level, communication-economic control scheme is presented for multiple-bus microgrids with each bus having multiple distributed generators (DGs) connected in parallel. The control objective of the upper level is to calculate the voltage references for one-bus subsystems. The objectives of the lower control level are to make the subsystems' bus voltages track the voltage references and to enhance load current sharing accuracy among the local DGs. Firstly, a distributed consensus-based power sharing algorithm is introduced to determine the power generations of the subsystems. Secondly, a discrete-time droop equation is used to adjust subsystem frequencies for voltage reference calculations. Finally, a Lyapunov-based decentralized control algorithm is designed for bus voltage regulation and proportional load current sharing. Extensive simulation studies with microgrid models of different levels of detail are performed to demonstrate the merits of the proposed control scheme.      

中厚板轧制制造执行系统的设计与实现

中厚板轧制过程计算机控制系统通常采用三级结构设计,一级为基础自动化级,二级为过程控制级,三级为生产管理级。在建立中厚板轧制制造执行系统（Manufacturing Execution System,MES）过程处理模型的基础上,基于工业以太网构建系统的体系结构,分析了所建立系统的架构特点、数据管理方式,研究了中厚板轧制MES系统与基础自动化级以及生产管理级之间以报文的形式实现实时、高效、稳定的数据通信的技术。该系统的设计目标是提升中厚板轧制过程控制的自动化程度,提高钢铁企业中厚板生产的精度和效率。系统在天津某钢厂已经投产运行,效果良好。     

高性能的交直流程控综合电源的设计与实现

文章介绍了交直流程控电源的工作原理，分析了电源的关键技术及解决的方法，阐述了特点，最后，给出了基本评价。     

Robustness and coordination in voltage control of large-scale power systems

In this paper it is shown how the robustness and the coordination of the voltage regulation actions for the transmission grid can be improved. Simpler approaches which ensure higher robustness and performances can be used if the control objectives are pursued at two hierarchical levels of different nature. Also, this is a way to coordinate means of control of different nature with a sufficient time and methodological separation in order to avoid negative mutual influence. At the first level, called the static level, optimal reachable set-points are computed for the second control level, called the dynamic level. The static level can be combined with the shunt reactive power compensation. The system non-linearities are taken into account at the static level while the dynamic level is a linear robust predictive control which takes into account the presence of asynchronous transmission delays. The predictive control strategy is based on the separation property; the output delays are handled using an original steady-state Kalman predictor of order equal to the length of the state of the system without delays. The robustness is improved at the dynamic level against uncertain delays, parametric uncertainties (like, e.g., moderate topological errors and load variations not taken into account in the control model) and unmodelled dynamics. The two-level organisation of the control allows, on one hand, to take into account the important evolutions of the system (like, e.g., large and known topological and load changes) and, on the other hand, a coherent hybrid reactive power control: the switched control of the grid shunt compensation for the reactive power is done at the static level while the reactive power injection provided by the generators is continuously handled at the dynamic level. This is a theoretical analysis of how concepts of automatic control and voltage regulation of power systems can be combined. To be applied as a control scheme, the results presented here should be adapted to a specific context (particularities of the power system and of the organisation of the power industry). They can be used, eventually in conjunction with other improvements, to existing horizontally-organised interconnections (in which all generators of a controlled region can be easily managed since owned by the same utility) or to face specific requirements of moving to the open access in the electric power industry like, e.g., tolerating simplified models in order to cover larger regions, taking into account the interaction between regions, recalibrating set-points, assisting human operator when necessary or facilitating implementation of mechanisms for the management of the reactive power based on price signals.     

Ad hoc网络功率控制策略研究

该文对MAC层需要引入功率控制进行了分析和研究,详细介绍了采用功率控制的原因及可行性,同时对功率控制的理论依据和准则进行了探讨。     

基于AT89S51的液位控制系统

本文介绍了一种基于AT89S51的液位控制系统。该系统能对液位进行巡回检测、显示和报警,同时采用增量式PID控制算法对液位进行智能控制。     

Modeling and control of workstation level information flow in FMS using modified Petri nets

A flexible manufacturing system (FMS) has a traditional structure of three levels: cell, workstation, and equipment. The workstation level plays an important role in the overall performance of the FMS. This paper focuses on modeling and control of the FMS workstation level information flow. In order to have a unified workstation level system structure, front-end interfaces are introduced as a standard communication medium between the workstation level and the equipment level. A detailed information flow analysis is then carried out on the workstation level. For modeling purposes, a modified Petri net is proposed with its increased modeling capability over an ordinary Petri net. It associates data structures with places and programs with transitions. Finally, the modified Petri net is used to model and control the FMS workstation level information flow. The designed control system has been implemented in a real manufacturing factory with satisfactory performance.     

锅炉汽包水位控制系统的研究

锅炉汽包水位是一种非线性、时变大、强耦合的多变量系统。在建直了锅炉汽包水位调节对象的数学模型的基础上，利用模糊控制理论设计锅炉水位控制系统，运用模糊控制与PID控制分别对汽包水位进行控制。介绍了控制器的设计和仿真分析，并应用MATLAB软件对汽包水位控制系统进行验证和仿真，给出了模糊控制方法与传统方法的比较结果，表明了模糊控制明显地改善了汽包水位控制系统的静、动态特性，从而实现了对锅炉汽包水位的最件实时控制。