中央空调变频定压变水量系统是不节能的

变频定压变流量节能系统是中央空调系统中应用最广的节能系统。然而它是不节能的，业界对此没有清楚的认识，只是错误地认为变频水泵或风机在定压变流量系统运行时的能耗也和转速的三次方成正比。从理论上证明了定压变流量节能系统为什么不节能。要根本改变变频节能的现状，必须改变治水的理念。     

变频调速技术在博纳地沥青混凝土搅拌设备中的应用

变频调速技术是通过改变电动机的输入电源频率来改变电动机的速度,调速范围大,静态稳定性好,运行效率高。文章对意大利进口设备博纳地MICS175-E220型沥青混凝土搅拌设备中应用的变频调速技术进行了分析和介绍。     

自动变频恒压供水与建筑消防控制

自动变频恒压供水与建筑消防控制郑州工业大学消防工程技术中心王赞瑞刘志伟全自动变频恒压供水设备属高新范畴，它能根据用水量的大小、出水口水压的变化，由微机或可编程序器控制的变频器随这自动改变频率，调整水泵的转速和投入运行的台数，因需自动恒压变量供水，从而...     

变频技术在节能降耗中的应用

<正>变频技术,是通过技术手段,来改变用电设备的供电频率,进而达到控制设备输出功率的目的。它是通过变频调速改变轴输出功率,达到减少输入功率、节省电能的目的,也是感应式异步电动机节能的重要技术手段之一。     

变频技术在节能降耗中的应用

<正>变频技术,是通过技术手段,来改变用电设备的供电频率,进而达到控制设备输出功率的目的。它是通过变频调速改变轴输出功率,达到减少输入功率、节省电能的目的,也是感应式异步电动机节能的重要技术手段之一。     

中央空调冷却水泵变频节能的讨论

与中央空调冷冻水泵变频相比，冷却水泵变频问题研究较少，争议也比较多。本文对有关冷却水泵变频节能的文献进行了辨析，认为冷却水泵变频是节能的，应该比冷冻水泵变频具有更大的节能空间。文献所提的计算节能量的方法不准确，不能用于评价项目的可行性。本文论证了一种计算冷却水泵变频节能的方法，可以简单但准确地计算冷却水泵变频的节能量，计算结果可以用于项目的可行性评价。     

空调系统水泵变频运行的节能分析

阐述了中央空调水泵变频节能机理和控制原理，并结合具体改造工程，对其变频运行的节能效益进行了分析，结果表明，水泵变频技术可行，节能显著。     

变频多联系统故障常见原因分析

20世纪90年代初由日本公司研制开发的变频多联系统，虽然已从交流变频改进成直流变频，但仍遗留了交流变频系统的一些缺点。所以，变频多联系统在安装后，经常会出现以下这些故障：     

变频调速在选泵中的初步研究及应用

离心泵的变频调速运行是指通过改变电动机的转速来改变水泵的性能曲线,从而变更工作点。由于城市管网用水量逐时变化,而变频调速运行既可以大大扩展离心泵的高效工作区,调速过程电动机的转差损耗又很小,因此,现在很多水厂的二级泵房都应用变频调速来达到节能的目的,这就要求我们在选泵的过程中充分考虑调速运行的节能作用。     

变频调速在空调水系统的应用研究

在研究水泵运行基本参数和特性的基础上，比较了采用滑差调速和变频调速的节能效果，提出了采用变频调速装置的水泵电气控制系统方案，讨论了变频调速装置控制特性的选择。     

热泵型一拖二变频空调器的开发

将国内外最新的变容量控制、电子膨胀阀控制、室内外机独立解耦控制和智能旁通除霜控制等控制方法与计算机仿真优化设计应用于热泵型变频一拖二空调系统的开发,给出了系统的原理、结构,并进行了实验研究。结果表明,系统运行稳定可靠,性能系数达到国内同类产品的领先水平,并超过了国家单元分体热泵空调器的节能标准。也为多元变容量空调系统奠定了理论与实验基础。     

Heating control strategy for variable refrigerant flow air conditioning system with multi-module outdoor units

The heating control strategy is key technology for stable and reliable heating operation of variable refrigerant flow air conditioning system with multi-module outdoor units. The synoptic control strategy is that the host module coordinates the system operation and adjusts the operation frequency of every module based on equal frequency allocation principle for suction pressure balance among modules. The heating control model including heating frequency adjustment, module switching condition and frequency allocation model has been built. Considering the discharge pressure disturbance, a certain discharge pressure region is taken as the control objective to adjust the frequency. And considering the lag between pressure and frequency, the restriction condition of discharge pressure and a certain judgment time are introduced into the model to avoid frequent module switching. Furthermore, different frequency allocation models have been built for increase and decrease of module number. In the model, when the module number increases and evenly allotted frequency to every module is less 70 Hz, one or two certain frequencies 70 Hz are distributed to the pre-existing thermo-on module(s) and the remaining frequency is distributed to ensuing thermo-on module so as to avoid sharp frequency fluctuation and inferior heating effect. Experiments demonstrate the feasibility of the control strategy.     

数字多功能专用消防给水设备控制器

介绍了一种数字多功能专用消防给水设备控制器,包括:可编程逻辑控制器,其上设置有控制指令接收端口、消防泵控制端口和变频控制端口,控制指令接收端口用于接收数字式控制指令,消防泵控制端口用于连接至消防泵主控制回路控制消防泵的启动或停止,变频控制端口用于连接至变频器控制变频器的运行;压力传感器用于连接在消防给水管网中以检测管网...     

太原市某集中供热换热站的节能运行

以太原市某集中供热换热站的运行调节为例,将水泵变频控制技术应用于两个换热站的二次网循环水泵上,分析了2007年～2011年四个采暖年度的运行工况特点,总结了变频调速控制技术的应用,指出了利用二次网循环水泵变频技术是降低换热站能耗的有效手段,从而达到节约能源、减少环境污染的目的。     

H∞ control in the frequency domain for a semi-active floor isolation system

A floor isolation system installed in a single floor or room in a fixed base structure is designed to protect equipment. With this configuration, the input motions to the floor isolation from the ground motions are filtered by the structure, leaving the majority of the frequency content of the input motion lower than the predominant frequency of the structure. The floor isolation system should minimize the acceleration to protect equipment; however, displacement must also be limited to save floor space, especially with long period motion. Semi-active control with an H_∞ control was adopted for the floor isolation system and a new input shaping filter was developed to account for the input motion characteristics and enhance the effectiveness of the H_∞ control. A series of shake table tests for a semi-active floor isolation system using rolling pendulum isolators and a magnetic-rheological damper were performed to validate the H_∞ control. Passive control using an oil damper was also tested for comparison. The test results show that the H_∞ control effectively reduced acceleration for short period motions with frequencies close to the predominant frequency of the structure, as well as effectively reduced displacement for long period motions with frequencies close to the natural frequency of the floor isolation system. The H_∞ control algorithm proved to be more advantageous than passive control because of its capacity to adjust control strategies according to the different motion frequency characteristics.     

Performance and robust stability trade-off in minimax LQG control of vibrations in flexible structures

An optimal robust Minimax LQG control of vibration of a flexible beam is studied in this paper. The first six modes of the beam in the frequency range of 0–800 Hz are selected for control purposes. Among these modes, three modes in the frequency range of 100–400 Hz are used for control, while the other three modes are left as the uncertainty of modeling. Both the model and the uncertainty are measured based on experimental data. The nominal model is identified from frequency response data and the uncertainty is presented by a frequency weighted multiplicative modeling method. For the augmented plant consisting of the nominal model and its accompanied uncertainty, a Minimax LQG controller is designed. A trade-off between robust stability and robust performance is shown by selecting two different choices of uncertainty modeling. Simulation results show that the proposed robust controller increases the damping of the system in its resonance frequencies.     

变频调速技术在电厂的应用及其节电效果

对变频调速技术进行了介绍,结合变频调速在电厂中的应用,对变频调速的节电效果进行了分析,论述了变频调速装置产品的情况,以促进变频调速技术在电厂节能改造中的应用。     

Study on adaptive‐passive eddy current pendulum tuned mass damper for wind‐induced vibration control

Tuned mass dampers (TMDs) are used to control wind‐excited responses of high‐rise building as traditional vibration control devices. A TMD will have an excellent control effect when it is well tuned. However, a traditional passive TMD is sensitive to the frequency deviation; the mistuning in frequency and damping ratio both will decrease its control effect. In the previous research, an adaptive‐passive variable pendulum TMD (APVP‐TMD) is proposed, which can identify the TMD optimal frequency and retune itself through varying its pendulum length. However, it is found that the frequency variation will change the TMD damping ratio, and an unreasonable damping ratio will lead to a decrement in the robustness of a TMD. In this study, an adaptive‐passive eddy current pendulum TMD (APEC‐PTMD) is presented, which can retune the frequency through varying the pendulum length, and retune the damping ratio through adjusting the air gap between permanent magnets and conductive plates. An adjustable eddy current pendulum TMD (PTMD) is tested, and then, a single‐degree‐of‐freedom (SDOF) primary model with an APEC‐PTMD is built, and functions of frequency and damping ratio retuning are verified. The 76‐story wind‐sensitive benchmark model is proposed in the case study. The original model without uncertainty and ±15% stiffness uncertainty models are considered, and response control effects of different controllers are compared. Results show that because the APEC‐PTMD can both retune its frequency and damping ratio; it is more robust and effective than a passive TMD. It is also found that the APEC‐PTMD has a similar control effect with the active TMD, with little power consumption and better stability.     

Wind power penetration impact on power system frequency

The incorporation of large amounts of wind power in power systems poses huge challenges. Especially with the growth of wind power generation, more rule reserves would be essential, the capability of the power system to offer classical regulating power would be reduced and the dynamic stability of the grid frequency under large oscillations would be compromised. In this paper, to investigate the integration of large-scale wind power generation in power systems and its active power control, a novel method and solution dealing specifically with the electric frequency stability and high wind power penetration is presented. So, the impacts of wind power on a balancing area's frequency control specification and studies the wind power impacts power system control. The proposed method has been applied to a three-area Automatic Generation Control model to verify these impacts. The simulation results obtained show that power system control indices deteriorate as wind power penetration increases.     

应用神经元自适应PSD控制变频空调系统的仿真研究

以变频空调系统为研究对象,将自适应控制与神经元PID控制相结合,建立了空调系统的神经元自适应PSD控制模块,并建立了模型,进行了仿真研究。结果表明,与常规PID控制相比,该控制方法具有较强的自适应、自学习、自组织能力和较好的鲁棒性,控制算法简单,容易实现,适合变频空调系统的实时控制。