变频调速技术在风机上应用的节能效果分析

本从定性和定量的角度,分析、介绍变频调速技术在风机上的应用,阐述该技术的应用前景。

软启动器在风机上的应用

分析了软启动器的功能、特性。简介软启动器应用于风机上的优点，并指出在设计、使用和现场调试中应注意的问题。

组态软件在风机测试及控制中的应用与改进

本文介绍了在风机性能测试中使用MCGS组态软件,设计了一套自动采集、处理、显示数据和性能曲线绘制,并且可以实现风机转速调节的系统。针对使用中组态软件存在的一个具体问题,进行了深入的分析,并提出了解决方案。

DEH控制系统简介及在风机控制系统中的应用

主要介绍了DEH(Digital Electro-Hydraulic Control System)控制系统,以及该系统研究方法的确认,系统建模与仿真的思想方法,DEH控制系统在汽拖轴流压缩机机组控制中的作用。

Zonal Coupling Analysis Method of Seismic Response of Offshore Monopile Wind Turbine

The seismic safety of offshore wind turbines is an important issue that needs to be solved urgently.Based on a unified computing framework,this paper develops a set of seawater-seabed-wind turbine zoning coupling analysis methods.A 5 MW wind turbine and a site analysis model are established,and a seismic wave is selected to analyze the changes in the seismic response of offshore monopile wind turbines under the change of seawater depth,seabed wave velocity and seismic wave incidence angle.The analysis results show that when the seawater increases to a certain depth,the seismic response of the wind turbine increases.The shear wave velocity of the seabed affects the bending moment and displacement at the bottom of the tower.When the angle of incidence increases,the vertical displacement and the acceleration of the top of the tower increase in varying degrees.

F-301风机节能涂料

一、概述F—301风机节能涂料是鞍钢矿山公司动力厂于1987年研制成的一种新型节能涂料。经过省级鉴定认为:"F 301"节能涂料填补了国内外空白。应用该料于风机上,达到了节能目的,为老风机的节能改造找到了一条切实可行的新途径,有助于使我国生产的新型风机的效率达到国际先进水平。

市政污水行业中鼓风机的应用分析

随着社会经济的发展,污水处理行业也得到了前所未有的发展,随之污水处理设备制造业也得到了发展。对当前污水处理使用的鼓风机设备的发展现状进行了描述,并进一步对我国污水处理厂的鼓风机设备选型问题进行探讨,着重分析了不同工艺、不同规模的污水处理厂鼓风机的选型应用问题。

Wind?Induced Interference Effect Between Newly?Built Cooling Tower and Existing Cooling Tower

Disturbance effect is one of the important factors for wind damage to large cooling towers.Existing studies on the wind-induced interference of cooling tower groups are aimed at the same size and the lack of wind-induced interference effects between cooling towers of different sizes.With the background of the additional cooling tower project at Shandong Luxi Power Plant in China,the rigid body pressure wind tunnel test is carried out to obtain 194 conditions for the three combinations of the existing four-tower combination(small size),the new two-tower combination(large size)and the six-tower combination surface wind pressure distribution.Numerical simulation of the surrounding flow field of the cooling tower group with the most unfavorable interference condition of the six-tower combination is conducted using the computational fluid dynamics(CFD)method.Based on this,the characteristics of the average and pulsating wind pressure distribution of the cooling tower surface under the six-tower combination are mainly studied,and the load interference coefficients of the large-sized cooling tower and the small-sized cooling tower under the three tower group combinations are compared.The velocity flow field and vorticity changes around the cooling tower group at unfavorable wind angles are analyzed,and the wind-induced interference mechanism between cooling tower groups of different sizes is mainly refined.Research shows that the interference effect between such cooling tower groups of different sizes is much larger than that of cooling tower groups of the same size,which is specifically manifested as the enhancement effect of small-sized cooling towers and the shielding effect of large-sized cooling towers.The interference coefficient of large-sized cooling tower groups increases by 28%,and the interference coefficient of small-sized cooling tower groups decreases by 6.4%.The airflow acceleration caused by the pinch effect between small-sized cooling tower groups has an adverse effect on large-sized cooling towers and can significantly increase the magnitude of local wind load.The shielding effect of large-sized cooling towers can reduce the overall wind load of small-sized cooling towers.The research conclusions can provide the basis of wind load value design for wind resistance design of such large cooling tower addition projects.

Analysis of Offshore Wind Power： Application to Southern Thailand

This paper presents an analysis of a pre-feasibility study of a 10 MW offshore wind power project in Nakhon Si Thammarat province, southern Thailand. The wind speeds at the hub heights of large scale wind turbine generators （WTG）, i.e. 80-100 m, were extrapolated using monthly mean wind shear coefficients and the l/7th exponent. Using WAsP 9.0, the annual energy production from several models of offshore wind farms using different WTG was analyzed. The capacity factor and the cost of energy were then computed. Using best available estimates, the analysis shows that the estimated annual mean offshore wind speeds at 80-100 m were in the range of 6.4 and 8.3 m/s. The annual energy production by the wind farm from nine models of wind turbine generators were in the range of 20-39 GWh/year, corresponding to a capacity factor in the range of 26-46%, while the cost of energy was 12-15 US cent/kWh.

The Applications of High-voltage variable frequency speed regulation System in Main Exhauster of Sintering

Main Exhauster is one of the main equipment of sintering production. It needs to consume a lot of electricity. Therefore, the system＇ s reconstruction for energy-saving will effectively reduce electricity for the production. The paper takes an iron and steel enterprise that had successfully transformed the synchronous motors of main exhauster of sintering as an example, which describes the application of high-voltage variable frequency speed regulation system in main exhauster of Sintering, so as to provide a reference for other iron and steel enterprises.

State-Model Based Time-Domain Diagnosis of Internal Faults for Permanent Magnet Synchronous Machine Wind Application

Upon occurrence of an internal fault on the PMSM （permanent magnet synchronous machine）, the topology of the stator is amended causing structural imbalances due to the change of the connection within the windings. In this work, a state model of internal faults of the PMSM is developed. This model is in the （abc） reference frame. The modeling approach is based on the assumption that each stator phase is replaced by two major and minor sub-windings. This model is used subsequently in the residual generation for diagnosis. The fault indicators are obtained by the projection in parity space and estimated using the Luenberger observer. A scenario of fault inter-turn by the short-circuit occurring between phase （a and b） is validated by simulation.

Magnetic Gearbox with an Electric Power Output Port and Fixed Speed Ratio for Wind Energy Applications

Mechanical gearboxes are typically employed with doubly-fed induction generatur-based wind turbines. The main drawback of this solution is the gearbox＇s reliability and maintenance. Using magnetic gearbox in conjunction with the doubly-fed induction generator is an emerging alternative being promoted by the research community which maintains the reduced size doubly-fed machine and overcomes the mechanical gearbox problems reported by field experience. This paper proposes a novel magnetic gearbox configuration in which a conventional planetary magnetic gearbox is equipped with n-phase coils fitted around the ferromagnetic pole-pieces to extract output electrical power. The turbine mechanical power is thus divided into mechanical power to drive the electrical generator and extra electrical power that can be diverted into a storage system to perform the power leveling function. The proposed configuration can also be used to freely modify the power-speed characteristic as seen by the electrical generator, a highly needed feature for grid frequency support.

Fuzzy Logic Controlled Dual Active Bridge Series Resonant Converter for DC Smart Grid Application

Over the last few years, smart grids have become a topic of intensive research, development and deployment across the world. This is due to the fact that, through the smart grid, stable and reliable power systems can be achieved. This paper presents a fuzzy logic control for dual active bridge series resonant converters for DC smart grid application. The DC smart grid consists of wind turbine and photovoltaic generators, controllable and DC loads, and power converters. The proposed control method has been applied to the controllable load＇s and the grid side＇s dual active bridge series resonant converters for attaining control of the power system. It has been used for management of controllable load＇s state of charge, DC feeder＇s voltage stability during the loads and power variations from wind energy and photovoltaic generation and power flow management between the grid side and the DC smart grid. The effectiveness of the proposed DC smart grid operation has been verified by simulation results obtained by using MATLAB and PLECS cards.

Microcontroller-Based Variable Speed Drive for Three-Phase Induction Motor in Cooling Applications

This paper presents an electronic VSD （variable speed drive） for three-phase IM （induction motor） using a microcontroller. The VSD is designed for cooling applications where the 1M is coupled to a cooling fan. The drive receives temperature feedback from objects to be cooled and output a corresponding frequency to the IM. A prototype of the VSD is constructed to control a 175 W, four pole, squirrel cage three-phase IM. The heart of the control circuit is a low-cost microchip＇s PICI6F777 microcontroller which is programmed using C language to generate variable frequency SPWM （sinusoidal pulse width modulation） switching signals. These switching signals are fed to an 1GBT inverter. The VSD constructed can be switched between two modes of speed control＂ automatic temperature-controlled mode and manual user-controlled mode. Cost savings using the prototype are demonstrated.

Investigation on Multi-objective Performance Optimization Algorithm Application of Fan Based on Response Surface Method and Entropy Method

A multi-objective performance optimization method is proposed, and the problem that single structural parame- ters of small fan balance the optimization between the static characteristics and the aerodynamic noise is solved. In this method, three structural parameters are selected as the optimization variables. Besides, the static pressure efficiency and the aerodynamic noise of the fan are regarded as the multi-objective performance. Furthermore, the response surface method and the entropy method are used to establish the optimization function between the op- timization variables and the multi-objective performances. Finally, the optimized model is found when the opti- mization function reaches its maximttm value. Experimental data shows that the optimized model not only en- hances the static characteristics of the fan but also obviously reduces the noise. The results of the study will provide some reference for the optimization of multi-objective performance of other types of rotating machinery.

Transient stability probability of a power system incorporating a wind farm

An analytical approach for probabilistic evaluation of transient stability of a power system incorporating a wind farm is presented in this study. Based on the fact that the boundary of practical dynamic security region(PDSR) of a power system with double fed induction generators(DFIG) can be approximated by one or few hyper-planes in nodal power injection space, transient stability criterion for given configurations of pre-fault, fault-on and post-fault of a power system is to be expressed by certain expressions of linear combination of nodal injection vector and the transient stability probability(TSP) is further obtained with a much more simplified expression than the complex integral. Furthermore, considering uncertainties of nodal injection power including wind power and load, TSP is calculated analytically by Cornish-Fisher expansion, which can provide reliable evaluation results with high accuracy and much less computing time compared with Monte Carlo simulation. TSP and its visualization can further help operators and planners be aware of the degree of stability or instability and find critical components to monitor and reinforce. Test results on the New England 10-generators and 39-buses power system show the method's effectiveness and significance for probabilistic security assessment.

Studies on a low Reynolds number airfoil for small wind turbine applications

In contrast to large horizontal axis wind turbines (HAWTs) that are located in areas dictated by optimum wind conditions, small wind turbines are required for producing power without necessarily the best wind conditions. A low Reynolds number airfoil was designed after testing a number of low Reynolds number airfoils and then making one of our own; it was tested for use in small HAWTs. Studies using XFOIL and wind tunnel experiments were performed on the new airfoil at various Reynolds numbers. The pressure distribution, C p , the lift and drag coefficients, C L and C D , were studied for varying angles of attack, α. It is found that the airfoil can achieve very good aerodynamic characteristics at different Reynolds numbers and can be used as an efficient airfoil in small HAWTs.

Recent progress in random metric theory and its applications to conditional risk measures

The purpose of this paper is to give a selective survey on recent progress in random metric theory and its applications to conditional risk measures.This paper includes eight sections.Section 1 is a longer introduction,which gives a brief introduction to random metric theory,risk measures and conditional risk measures.Section 2 gives the central framework in random metric theory,topological structures,important examples,the notions of a random conjugate space and the Hahn-Banach theorems for random linear functionals.Section 3 gives several important representation theorems for random conjugate spaces.Section 4 gives characterizations for a complete random normed module to be random reflexive.Section 5 gives hyperplane separation theorems currently available in random locally convex modules.Section 6 gives the theory of random duality with respect to the locally L0-convex topology and in particular a characterization for a locally L0-convex module to be L0-pre-barreled.Section 7 gives some basic results on L0-convex analysis together with some applications to conditional risk measures.Finally,Section 8 is devoted to extensions of conditional convex risk measures,which shows that every representable L∞-type of conditional convex risk measure and every continuous Lp-type of convex conditional risk measure(1 ≤ p < +∞) can be extended to an L∞F(E)-type of σ,λ(L∞F(E),L1F(E))-lower semicontinuous conditional convex risk measure and an LpF(E)-type of T,λ-continuous conditional convex risk measure(1 ≤ p < +∞),respectively.

Results and Analysis of a L2F Flow Field Investigation within a High-Speed High-Pressure Centrifugal Compressor

The paper describes experimental results obtained using a laser two-focus anemometry technique in a high-speed, high-pressure ratio unshrouded centrifugal compressor. Measurements in such a small impeller are extremely difficult as the flow is restricted to narrow passages and as the temperature rise is very high. Even if the working principle of laser anemometry is well documented in literature, some specialities of our LA system are discussed.A description and an analysis of the inlet now field, based on integral methods, are proposed. Some passage velocity contours are presented. Whereas a potential flow structure exists up to the high meridional curvature region, the throughfiow pattern is largely distorted in the radial part of the impeller.Noticeable differences in ftow pattern between both channels are found, particularly through the low momentum fluid zone. A qualitative study of the vortical mechanisms ascribes them to the tip clearance effects.