塔式起重机PID变频调速实验研究

为了使塔式起重机变频调速更加平稳,进行了实验室条件下的研究,建立了PC控制器、变频器、传感器、数据采集系统以及起升机构的闭环控制系统。通过对系统加入PID前后控制效果对比,认为PID控制器能明显提高起升系统工作精度,且使系统运行更加平稳。     

PID调节在花地河南北闸门控制中的应用

在闸门控制中,应用的控制方式有多种其中调节器控制方式为比例、积分、微分控制,简称PID控制,又称PID调节。具有PID参数自整定功能的智能调节器(intelligent regulator),其中PID控制器参数的自动调整是通过智能化调整或自校正、自适应算法来实现,其是利用其闭环控制模块来实现PID控制,它以其结构简单、稳定性好、工作可靠、调整方便、控制准确而成为工业控制的主要控制技术之一,实际应用中也有PI和PD控制。PID控制器就是根据系统的误差,利用比例、积分、微分计算出控制量进行精确控制。     

自适应模糊PID控制器的研究

除了开／关控制,常规PID控制器是HVAC系统现场控制中应用最为广泛最基本的控制器,但对于非线性、时变的系统,常规的PID控制则很难达到满意的控制效果。本文提出了自适应模糊PID控制器模型,可以根据系统误差和误差变化率不断对PID控制器的输出进行在线调整。以某空调房间温度控制系统为研究对象,对自适应模糊PID控制器和常规PID控制器进行了对比。计算结果表明,自适应模糊PID控制器具有良好的动、静态性能,并且鲁棒性较强。     

全数字化多晶硅还原电源控制系统的设计

本文针对行业普遍使用的改良西门子生产方法,设计出一套多晶硅还原电源控制系统。该系统包括多晶硅还原电源控制器、光电转换装置和触摸屏人机界面,该系统根据生产工艺流程利用PID闭环控制算法和电压叠层原理控制电流在目标值。控制器采集电压、电流和启停控制信号,接收DCS或人机界面给定的目标电流,通过PID算法计算出晶闸管导通角,并以光信号的形式发出;光信号经过光电装换装置转成电信号去触发晶闸管的导通,从而实现控制电流的目的。现场运行结果表明,该控制系统性能可靠,电源利用率高。     

基于模糊自适应PID的数控机床进给控制器设计

针对数控机床进给系统特点及其性能要求提出了一种参数自整定模糊PID控制器,利用模糊推理的方法实现对PID参数的在线自动调整.事实上,所提出的控制方法是结合模糊控制和常规PID控制两种控制理论,因此,所设计的控制器兼有模糊控制和PID控制的优点.仿真结果表明,该控制器明显地改善了机床进给控制系统的动态性能,并且此方法计算量少、鲁棒性强、动态品质优良、易于实现、便于工程应用.     

恒压供水系统的智能PID控制研究

根据循环冷却水供水系统非线性、大滞后、参数时变的特点,本文结合模糊控制及变异算法以及传统PID控制各自的优势,设计出一种新型的控制器:即采用遗传算法完成对PID控制参数初值的整定,同时利用遗传算法整定的初值进行模糊自适应PID控制器的初步设计,最后利用禁忌搜索算法对模糊控制规则进行优化。仿真结果表明,这种控制器能根据被控对象不同工况变化的要求,获得满意的动态和静态控制特性,抗干扰能力很强。     

应用于AQM的神经网络PID控制器优化设计

主动队列管理(AQM)在解决网络拥塞问题中扮演着重要角色,为了解决AQM的PID参数不能随时间调整,且不能适应动态和非线性网络的缺点,本文提出了一种新的PID控制器算法。新算法结合了PID控制和神经网络算法两者的优点,同时新的AQM算法在时延、吞吐量和稳定性方面均优于一般的PID控制器。     

用于小高层住宅的模糊PID变频供水系统

为保证小高层住宅供水压力稳定性并达到节能,采用了模糊自适应PID控制技术,利用模糊推理在线自动整定PID控制器的参数,较好地克服了传统PID控制器稳定性差、参数整定困难的缺点.将供水母管压力与设定压力的偏差经模糊自适应PID运算,通过可编程控制器调节变频器的输出,可自动调整水泵运行的台数和电机转速,实现闭环自动调节恒压供水.     

变风量空调系统的优化控制研究

在变风量空调系统中,为了减少系统能耗并对静压控制回路进行稳定而有效的控制,提出了一种静压优化控制方法,根据各末端风阀开度的变化确定空调系统所需的最小静压设定值,采用粒子群算法优化神经网络,调整PID控制器的3个参数,通过PID控制器调节变频风机的频率,把实际静压控制在设定值附近。通过仿真和实验对该控制方法的有效性和优越性进行了验证。结果表明,采用该方法在满足空调系统负荷需求的前提下能使末端阀门处于较大的开度,降低了风机的运行频率,改进了控制质量,提高了控制精度,不仅能够有效节能,还具有较强的鲁棒性。     

混凝土泵车主泵转速感应控制系统研究

在PID控制器的基础上,利用单神经元的自学习性能实现了对PID参数的在线自整定自适应控制,并且在MATLAB软件下将该控制器在混凝土泵车主泵的转速感应控制系统中进行了研究.仿真结果表明,单神经元PID控制能使系统达到满意的控制效果.     

一种新型直接膨胀式温湿度独立控制恒温恒湿空调系统

为了消除传统恒温恒湿空调系统中冷热抵消现象,提出了一种新型直接膨胀式温湿度独立控制恒温恒湿空调系统(下称新型空调系统).该空调系统通过组合三级直接膨胀式制冷单元、加热器、加湿器,并配备特有的控制策略,可以在满足恒温恒湿环境一定温湿度控制精度的前提下,实现温湿度解耦控制.该空调系统不会造成投资成本大幅增加,并具备结构简单...     

Multivariable control of indoor air temperature and humidity in a direct expansion (DX) air conditioning (A/C) system

Controlling indoor humidity at an appropriate level is very important since this affects occupants' thermal comfort and indoor air quality (IAQ). The paper presents an investigation on developing a multi-input multi-output (MIMO) control strategy for simultaneously controlling the indoor air temperature and humidity by varying the speeds of both compressor and supply fan in an experimental DX A/C system. The MIMO-based controller was designed based on the linearized dynamic model of the experimental DX A/C system. The Linear Quadratic Gaussian (LQG) technique was used in designing the MIMO-based controller. The controllability tests with respect to both the disturbance rejection capability and the command following capability were carried out to assess the control performance of MIMO controller. The results of disturbance rejection capability test showed that the MIMO control strategy can effectively maintain the indoor air temperature and humidity to their respective settings after an unmeasured heat load disturbance was imposed by simultaneously varying speeds of both the compressor and the supply fan of the DX A/C system. Furthermore, in the command following capability test for indoor air temperature, the test results showed that the indoor air temperature can be controlled to its new setting while indoor humidity remained unchanged. Similar test results were also observed in the command following capability test for indoor humidity. Therefore, the MIMO controller developed can effectively control indoor air temperature and humidity simultaneously by varying compressor speed and supply fan speed of the DX A/C system. Compared to the previous related studies using conventional on–off control method or single-input single-output (SISO) control strategy, which can only effectively control either air temperature or relative humidity, the MIMO controller can simultaneously control the indoor air temperature and humidity with adequate control sensitivity and accuracy. The application of MIMO control strategy developed can be extended to other HVAC systems in the future to improve their operating performance and energy efficiency.     

基于地下室恒温恒湿空调机组的控制策略研究

基于已有的直流变频变风量恒温恒湿空调机组,针对地下建筑常年湿度较大的情况,提出一种变频变风量结合主、副电子膨胀阀的多变量控制策略,并通过LabVIEW软件实现编程控制。为验证控制方法的可行性,采用模拟负荷发生器在实验室中模拟地下空间的实验热湿环境特征,根据机组处理的热湿能力选取不同热湿负荷工况下进行实验室温湿度控制实验。实验结果表明,在此控制方法下该恒温恒湿机组能满足实验工况下的地下空间热湿的控制要求,在两组总负荷不同的情况下,干球温度和相对湿度都能稳定在设定值附近,系统的控制精度和稳定性良好。     

LabVIEW环境下空调机组PLC控制程序的编制

本文介绍如何运用LabVIEw图形模块化的编程环境并使用PLC对空调机组的运行进行控制,编制基于LabVIEW的梯形图PLO控制程序,实现对空调机组送风温、湿度的控制。     

手术室温湿度控制方式探讨

在综合分析医院手术室温湿度数据的基础上,依据多年经验的总结,提出对手术室温湿度控制逻辑的新思路：在手术室温度数据采集点为送风温度,手术室湿度采集点为回风湿度,采用PID控制空调机组冷热源及加湿器的温湿度输出,实现了手术室温湿度控制的基本恒定,缩小了温湿度控制的波动范围,加快了手术室温度的调节速度     

某大型车间空调机组控制策略探讨

结合工程实例,介绍了空调机组的特点,并从运行模式、温度控制、风量控制、保护控制四个方面讨论了其控制策略,实现安全运行、精确控制、节能高效的目的。     

卷烟厂空调系统消除再热的节能控制方案

本文针对卷烟厂工艺性空调系统为满足室内温湿度控制精度,在夏季除湿工况下通常需再热的特点,提出了一种通过变风量调节和主副表冷器独立控制消除再热的节能控制方案,并结合投入运行的实际工程测试数据分析,对所述的节能控制方案进行了验证。     

A comparative study of different control strategies for indoor air humidity

There has been a rising concern in controlling the high indoor humidity of hot and humid countries. When an air-conditioned space experiences only part of its design heat load, its humidity tends to rise as a result of the air-conditioning system trying to control the indoor temperature by reducing its cooling capacity. In this study, the part-load dehumidification performances of three temperature control strategies are compared, namely, chilled water flow control, bypass air control and the variable air volume control. Coil simulations are employed to study the part-load performance of these control strategies. The coil model has been validated with experimental data to within ±6.5%. The relative humidity of a space depends of factors such as design sensible heat factor of the space, temperature control strategy employed and load condition experienced by the space. Simulation results have indicated that chilled water control strategy results in the highest indoor humidity throughout the range of conditions studied while variable air volume system provides highly effective dehumidification performance of the cooling coil. Bypass air control appears to be a good option for adoption as it is able to provide an acceptable humidity over a wide range of load conditions without having to affect the air movement within the space.     

某半导体生产车间温湿度控制系统设计

本文系统地介绍了某企业半导体生产车间净化空调的数字式温湿度控制系统,该系统可靠性高,且结构简单,可以实现对净化厂房内温湿度的自动调节,为类似工程的设计提供了参考。     

Optimization of a liquid desiccant based dedicated outdoor air-chilled ceiling system serving multi-zone spaces

A liquid desiccant based dedicated outdoor air-chilled ceiling (DOAS-CC) system is proposed to serve a multi-zone space. The outdoor airflow rate and the supply air humidity ratio are two crucial variables in such a system, which significantly influence indoor thermal comfort, indoor air quality and energy consumption. Two strategies are presented to optimize these two variables in the study. They are the demand-controlled ventilation (DCV) strategy and the supply air humidity ratio set-point reset strategy. To evaluate the performances of these two strategies, a basic control strategy, i.e., the strategy adopting constant ventilation flow rate and constant supply air humidity ratio, is selected as the benchmark. Performances of the two strategies in terms of indoor air temperature, relative humidity and CO₂ concentration as well as energy consumption are analyzed using simulation tests. The results show that the supply air humidity ratio set-point reset strategy is effective for the indoor air humidity control. It can save about 19.4% of total energy consumption during the whole year. The DCV-based ventilation strategy can further reduce about 10.0% of energy consumption.