bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct Torque Control for Brushless Doubly-Fed Machine Based on Fuzzy-PI Regulator
Authors: Peng Xiao , Li Mo Fa , Li Yong Jian
Published: December 2012

The inverter switch state is based on the torque error and the stator flux amplitude error in the hysteretic controller which is adopted on the traditional direct torque control for the brushless doubly-fed machine, in this way, current and flux are distorted that results torque ripple in low speed range, even more influents control effect of the whole system. According to this problem, a new direct torque control method with fuzzy-PI regulator for the brushless doubly-fed machine is presented in this paper, applying the fuzzy theory to design controller parameters. The simulation results show that the method is effective to improve the dynamic characteristics of the motor, reduce the torque ripple, improve the speed and the torque control precision, and expand the direct torque control system of speed range.
New Implementation of Position Sensorless Control Based on the AC Component of SNP for Brushless DC Motor
Authors: Yang Ying , Tu Xiao Wei , Yu Zhi Xuan
Published: December 2012

Zero-crossing detection with voltage comparator in position detection method based on the AC component of Supposing Neutral Point(SNP) induced sensitivity to noise. In this paper, it is proposed that the ASIC ML4425 should integrate AC component instead of the terminal voltage and phase-locked loop(PLL) was used to determine the proper commutation sequence for the BLDC motor. Basic principle and implementation of the ASIC-based sensorless controller will be presented and experiments will be given to verify the control strategy.
Sliding Mode Control with a New-Style Disturbance Observer for Low-Speed Permanent Magnet Synchronous Motor
Authors: Chen Shao Chang , Li Hong Jiang , Huang Cong Wu , Xiong Hao
Published: December 2012

A siding mode control (SMC) strategy with a new-style disturbance observer is proposed for the permanent magnet synchronous motor (PMSM), which has vibration problems of rotating speed and electromagnetic torque in low speed range. In the paper the mathematical model of a PMSM composed of parameter uncertainty and disturbance is established, a SMC which can effectively improve system robustness and response is designed, a novel disturbance observer to estimate the disturbance caused by the model parameter and load changes is used, the estimated value to build a feed-forward compensation added to a SMC input is employed, and finally the stability of the scheme is analyzed. Simulation results show that the algorithm has a faster response, less stabilization error compared with the traditional SMC, and the vibration is restrained effectively.
Thrust Performance Analysis of Cylindrical Permanent Magnet Linear Synchronous Motor Based on Finite Element Method
Authors: Xiong Hao , Meng Guang Wei , Yang Zhan Qing , Zhou Li Bing
Published: December 2012

The cylindrical permanent-magnet linear motor (PMLSM), as a linear driving device, produces the electromagnetic force to cause linear motion through the electricity directly and does not need additional mechanical conversion devices to transform rotation to linear motion. This paper calculates the electromagnetic distribution and force of two kinds of cylindrical PMLSM by ANSYS, and compares and analyzes their thrust performance. It is concluded that a radially magnetized cylindrical PMLSM is suitable for the applications requiring smaller speed variation while an axially magnetized one possesses a bigger thrust and thrust variation yet.
Finite Element Analysis of Permanent Magnet Induction Generator
Authors: Diao Tong Shan , Wang Xiu He
Published: December 2012

Many reliable energy conversion methods are constantly being sought for renewable energy applications. The permanent magnet induction generator is a new concept which uses permanent magnets to provide the flux in the machine. This will lead to an improved power factor and higher efficiency. This type of generator is a very attractive renewable solution. In this paper ,firstly,introduce the structure and principle of permanent magnet induction generator. Secondly, the dynamic starting performance of this machine is studied. Finally, finite element analysis and simulation are carried out, the results verify the performance of the machine meet the design requirements.
Simulation Research on the Single-Phase Operation of a Line Start Permanent Magnet Synchronous Motor
Authors: Pei Ying , Wang Xiu He , Liu Gang
Published: December 2012

In this paper, the single-phase operation of a line start permanent magnet synchronous motor (LSPMSM) has been analyzed in detail. At first, based on symmetrical component method, the condition for balanced operation is derived. Secondly, steady state performances are analyzed by computer programming. Thirdly, the transient performances are studied on the basis of MTLAB/Simulink. The results demonstrated that the LSPMSM running on a single-phase supply has lower efficiency but higher power factor than three-phase balanced operation, besides good starting and operating performances can be achieved.
Mathematical Model Research of Six-Phase PMSM
Authors: Su Jian Yong , Yang Jin Bo , Yang Gui Jie
Published: December 2012

The six-phase permanent magnet synchronous motor (PMSM) is designed with two sets of Y-connected windings phase shifted by 30 electrical degrees. Two mathematic models of six-phase PMSM are established by different methods, which are based on dual d-q transformation and decoupling vector space respectively. By the dual d-q transformation, the electromagnetic torque is calculated based on the two sets of Y-connected windings separately. By the decoupling vector transformation, extra vector subspace is established, in which the current components have no effect on the electromagnetic torque. According to the different models, two vector control systems for six-phase PMSM are presented. The relationship and equivalence of the two control methods are indicated through comparison analysis and open-loop simulation. And the closed-loop simulation and experiment results show that the two methods have consistent control performance
Research on Modulation Method and Characteristic Analysis of Faraday DC Optical Measurement System
Authors: Meng Lu , Dong Rui , Xiong Qing Fu , Wang Qian
Published: December 2012

The optical current transformer is an important content in smart grid research field. When the Faraday DC optical measurement system was used in DC current measurement, the low frequency noise caused by photo detector and measured signal were overlapped, which makes the measuring accuracy decrease. To solve this problem, the noise of photo detector is analyzed. Then, the frequency modulation is proposed for spectrum shifting. Furthermore, the principle of modulation method is deduced in formula, and the characteristics of deferent frequency are also analyzed. On this base, modulation signal source is designed. With LabVIEW program, the signal from modulation source is acquainted and analyzed. The results show that this modulation method can realize spectrum shifting and the designed signal source is able to generate waveform needed.
Development of Combined Cooling and Power System with NH3-H2O Absorption Cycle Driven by Solar Energy
Authors: Wang Chun Long , Liu Ye , Lian Xiao Long , Song Qing Yuan , Li Jin Ping
Published: December 2012

In recent years, a combined cooling and power system (CCPS) with NH3-H2O absorption cycle has been aroused great interests. The previous researches on CCPS have been reviewed to summarize the properties of working pair and the experimental apparatus and demonstration devices firstly. Then, a new CCPS driven by solar energy has been developed and discussed.
Research on on-Load Current Method for Detecting Fault of Transformer Core Based on the Vibration Analysis Method
Authors: Wu Xu Tao , Ding Pei , Yan Zhen Hua , Ji Sheng Chang
Published: December 2012

When vibration signal analysis method is used to monitor the transformer, the core vibration signal is often obtained as the transformer runs under no-load condition. In this paper, a method extracting core vibration signal without operating transformer under no-load condition was introduced. The transformer vibration accelerative signals at different on-load current and no-load condition were measured. From the fitted curve of on-load current versus fundamental frequency component of vibration accelerated signal, the value of fundamental frequency component was obtained when the on-load current was zero, which was almost equivalent to the fundamental frequency component of vibration accelerative signal measured under no-load condition, thus the fundamental frequency component of core vibration can be obtained by using on-load current method. The core with fault was finally monitored by using the on-load current method compared with wavelet package transform method. From the result of experiment, it can be seen this method is very useful to estimate the condition of the transformer core.
Research on the Technology of Converting the Existing AC Lines to DC Lines
Authors: Yang Wen Qing , Cao Wei , Wu Jian Kun , Chen Lin
Published: December 2012

Power transmission is a key link in power system. As the increase of power supply, the transmission capacity of the lines should be enlarged too. In the developed area, the right-of-way for transmission line is hard to be obtained. And converting the existing HVAC overhead transmission lines using HVDC technology could enhance the transmission capability. There are three possible plans for different HVAC transmission lines: single-pole HVDC, bi-pole HVDC and tri-pole HVDC.
Simulation of Electric Power Fluctuate Affect Transformer Substation Bus Voltage Wave by PSASP
Authors: Xu Hong Lei , Li Xiao Hu , Cao Yin Li , Yao Xu , Kang Yi , Li Xue Shi
Published: December 2012

This paper listed the mathematic model of transmission line firstly, and PSASP was used to simulate the fluctuate voltage of transformer substation which affected by wind generate electric power capacity which combined to the grid changed and the power flow of XINJIANG sent into GANSU changed. At the end, the conclusion and construction of improve grid running state was presented.
Hardware Design of a New Instrument to Control the Heat Pulse and Measure the Temperature of Stratum
Authors: Feng Cang Xu , Liu Zhen Shui , Cui Xiao
Published: December 2012

In this work, we report the design of a new instrument including one heat pulse circuit and three temperature measure circuits. Heat pulse control circuit can control the heating time of heater strip. The heating power is 0.5W and the duty time of every heat pulse is 8s. Three temperature measure circuits can measure the change of stratum’s temperature before and after accurately. The temperature resolution is 0.001°C, precision is 0.01°C and sampling rate is 1 Hz. The instrument can save the temperature data for every measure process. It is also provided with the data communication interface. The data saved in the instrument can export to computer through the interface. The instrument can measure the stratum’s temperature easily and reliably. The instrument will play a role in the studies of hydrogeology and environmental geology besides the application of Shallow Geothermal heat
Discriminating Measurement of Temperature and Strain by Using Long Period Grating’s Spectra
Authors: Yuan Zhao Ping
Published: December 2012

Discriminating measurement of strain and temperature is demonstrated by using a long period fiber grating according to its spectrum characteristics. The resonant wavelength of the first and third-order loss peak is selected, and temperature and strain sensitivity of each resonant wavelength are experimented. The self-wavelength shift resulting from parameter variation can be obtained by observing its corresponding spectrum. The temperature and strain sensitivity are calibrated. Both wavelengths have good linear response of temperature and strain in a certain variation range. Then, slandered matrix equation is set up and solved according to the corresponding parameter. Experimental results show root mean square deviation of ±16με and ±0.62°C for strain and temperature, respectively. This method can realize discriminating measurement of strain and temperature avoiding cross sensitivity. System accuracy is also improved efficiently.
MPPT Control for Current Source Converter Based PMSG Wind Energy Conversion System
Authors: Bao Jian Yu , Bao Wei Bing , Gong Jie
Published: December 2012

Current source converter (CSC) configuration tailored to high-power grid-connected wind energy conversion system (WECS) has been an attractive solution for direct drive of permanent magnet synchronous generators (PMSGs). A maximum power point tracking (MPPT) scheme for a PMSG-based WECS is presented in this paper. On the generator side, a fully controlled current source converter is inserted as a circuit interface to handle a wide range of the variable wind speeds. Rectifier side controller extracts maximum power through closed-loop regulation of generator speed. The available maximum power fed to the grid is adjusted by regulating dc-link output current of CSC according to the variable wind speed. Simulation results obtained from a megawatt PSIM model are provided to verify the proposed concepts.
Fast and Effective Power Modeling for SRAM Compiler
Authors: Song Qiang , Tan Shou Biao , Peng Chun Yu
Published: December 2012

An efficient SRAM power modeling method based on two formula techniques is proposed, which contains a mathematical method called two-dimensional bilinear interpolation function and a segment analysis on the basis of MUX. This scheme allows us to reach the accurate modeling of SRAM power consumption without complicated calculation and specific circuit analysis. Hsim simulation in 65 nm CMOS process shows our proposed method error is closed to 5%.
Enabling Virtual Machines and Scatter/Gather I/O Using ShernCod
Authors: Yao Xin , Li Yuan Yuan , Wang Ming Chun
Published: December 2012

Stable epistemologies and Internet QoS have garnered minimal interest from both cyberneticists and physicists in the last several years. Given the current status of semantic communication, scholars obviously desire the emulation of model checking. In this position paper, we concentrate our efforts on proving that suffix trees can be made homogeneous, scalable, and low-energy. Results showed that the well-known constant-time algorithm for the evaluation of DHCP is optimal, and ShernCod is no exception to that rule. Furthermore, our application successfully analyzed many flip-flop gates at once. This paper also disconfirmed not only that multi-processors and Smalltalk can collude to fulfill this objective, but that the same is true for model checking. Finally, this study provided evidences that the well-known pseudorandom algorithm for the improvement of 802.11b is in Co-NP.
Impacts of TCSC and FSC on the Power-Angle
Authors: Duan Zhi , Bao Hai , Shen Hong
Published: December 2012

The Characteristics of FSC (Fixed Series Compensation) and TCSC (Thyristor Controlled Series Capacitor) damping power-angle oscillation and increasing the limit of power transmission were analyzed. FSC can damp the power-angle in a certain extent. Based on the linear control combined with Bang-bang control strategy, TCSC can damp power-angle effectively. In the cases of only FSC, only TCSC and their combinations, simulation results demonstrate that TCSC is more effective than FSC in damping power-angle oscillation. A conclusion is made that taking effect and cost into consideration, TCSC and FSC in a certain percentage is appropriate.
Investigation and Improvement of Self-Oscillating Electronic Ballast for Local Fluorescent Emergency Light
Authors: Hamid Muhamad Fairus , Hashim Norazlan , Abidin Ahmad Farid
Published: December 2012

This paper presents an analysis and improvement of self-oscillation electronic ballast for local emergency light. The improvement circuit has been presented by replacing the original BJTs with MOSFETs as a switching device. Also, 555-timer has been used to drive the MOSFETs instead of the ballast feedback in the original circuit. This electronic ballast start and regulate fluorescent lamps by converting a DC supply to high ignition AC voltage by a rectifier circuit with switching frequency in the range of 20 kHz -1MHz. Operation at high frequency has two advantages; an improved efficiency and elimination of flickering in the lamps. The simulation has been done by using PSIM Simulink software and its results have been compared with experimental results. The results shows that by using MOSFETs as a switching device, the Total Harmonic Distortion (THD) has been reduced and the brightness of lamp tube has been increased greatly.
Comparative Analysis of the Control Rod Drive System
Authors: Han Wen Wei , Han Wei Shi , Guo Qing
Published: December 2012

This article has systematically summarized the recent research situation of control rod system in China and comparatively analyzed the features of a variety of control rod drive systems on a basis of brief introduction of common types of control rod drive system. It has been proposed to that the hydraulic control rod drive system have a great potential in a wide application concerning on ships, warships power reactors and protable desalination system.
Design of Process Controller Based on PCI Interface and CPLD Technology
Authors: Li Yu Sen , Sun Ying
Published: December 2012

In order to realize the sensor signal acquisition and analysis of data, according to data acquisition system design ideas of the PCI bus, applying to CPLD complex programmable controller and CH365 interface chip and combined with the actual needs of data collection ,designed a kind of low cost, high speed process controller. CPLD realizes data cache control and the control of reading. This design can gather 16 roads analog signals and real-time pulse signal of 8 roads on the same time, which includes a 16-bit digital output channel and a 32-bit counter, could be used in the real-time control.
The Analysis Research of Thermal System of Coal-Fired Power Plant and Examples of Applications
Authors: Li Jian Qiang , Chen Dan Dan , Wang He , Fu Xiao Fei
Published: December 2012

What the paper describes is to develop the performance calculation program and it will be used in the practical unit through analyzing the thermal process in the power plant, which is on the basis of the operation performance of the power plant equipment and the analysis of the calculation method in accordance with the first law of thermodynamics. We can be analyzed through calculating and quantifying the performance of the whole boiler, the turbine, the thermodynamic system and the power plant in detail. The operation quality and the intact degree of unit equipment can be evaluated by the operation personnel according to performance data. Finally, it is going to save energy reduce consumption, and realize the goal of improving level of the unit operation.
Research on Ripples Reduction of Flux Linkage and Torque for DTC
Authors: Liu Ying Pei , Li Ran , Zhang Zhi Chao
Published: December 2012

In order to reduce the ripples of flux linkage and torque for direct torque control (DTC) and ensure constant inverter switching frequency, permanent magnet synchronous motor (PMSM) DTC based on space vector modulation (SVM) and extended Kalman filter (EKF) is researched in the paper. Simulation results have shown that the inherent advantages of fast dynamic response of DTC are maintained, and flux linkage and torque ripples are effectively reduced. Speed is estimated accurately, and sensorless operation is realized.
Research on Control Strategy for the Three-Phase Grid-Connected Inverter
Authors: Qi Chun Qing , Ruan Yi , Cao Feng Wen
Published: December 2012

This paper proposes a control strategy，based on the grid voltage oriented vector control (VOC), which makes three-phase inverter control the active and reactive power of grid-connected inverter under the premise of the direct current control. This paper analyzes the principle of three phase photovoltaic grid connected inverter and describes the control structure of the inverter. The control strategy can overcome the deficiencies of the indirect current control scheme. This paper designs the current closed-loop control system, which not only improve the system dynamic response speed and output current waveform quality, while also reduce its sensitivity to parameter changes to improve the robustness of the system. The simulation results show the validity of control strategy proposed.
Development on Rehabilitation Instrument of Genu Varus or Valgum Based on Biomechanics
Authors: Li Hong Zhou , Lu Jie , Liu Nan Nan , Zhang Xv
Published: December 2012

This paper analyses deeply therapeutic theory of the genu varus or valgum and puts forward a physical orthopedic model that the patients are in different external force environment based on biomechanics and cartilage-derived growth theory. The mechanism structure and working principle of stretching unit, orthopedic unit and vibration unit are introduced and respective mechanical equations of above unit are established. The paper develops a prototype with which a lot of experiments and tests were made, the experiment results show that the structure of the prototype is reasonable and it can work effectively and reliably.
A Matrix Method for Describing the Power Transmission of Electric Network
Authors: Hao Zi Han , Bao Hai
Published: December 2012

Traditional power flow calculation can only supply the information of the conventional electric parameters, such as node voltage, branch current, power, etc. The transmission of power which is injected into the network by each power source, including power supply paths, power belongs, relationship among the power injected into each nodes, cannot be given. To solve this problem, this paper using the theory of the physical distribution of power network’s energy, proposes a matrix method for describing the power transmission, expresses the value and supply paths of the power from each single source in power network with the analytic method.
Protection Scheme for DC Microgrid Distribution System
Authors: Deng Ling Hui , Wang Zhi Xin , Duan Jian Min
Published: December 2012

The low voltage DC (LVDC) distribution system is a new concept and a promising technology to be used in the future smart distribution system having high level cost-efficiency and reliability. In this paper, a low-voltage (LV) DC microgrid protection system design is proposed. Usually, an LVDC microgrid must be connected to an ac grid through converters with bidirectional power flow and, therefore, a different protection scheme is needed. This paper describes practical protection solutions for the LVDC network and an LVDC system laboratory prototype is being experimentally tested by MATLAB/SIMULINK. The results show that it is possible to use available devices to protect such a system. But other problems may arise which needs further study.
Data Storage Strategy of Electric Energy Metering Production and Dispatching Platform under Intensification Mode
Authors: Huang Xiao Shu , Shao Yang , Wen Yang , Zhang Liang
Published: December 2012

Analyse the electric energy metering production mode and data characteristics of production and dispatching platform mode under intensification mode. Put forward a method of data partitioning by archived data zone, real-time data zone, sampled data zone and business-management data zone. Form the device’s owner identification by device table number shifting strategy and realize the high-speed data retrieval between every two of the zones by using the index of device to monitoring dot and main table retrieval. This strategy has been used in developing provincial production and dispatching platform of STATE GRID and raised the operating efficiency of the platform.
Two-Phase Flow Heat and Mass Transfer Model Construction and Experiment Study of the Fuel Evaporation Progress
Authors: Liu Bo Yun , Pu Jin Yun , Yi Xiang Lie
Published: December 2012

As for the time-dependent behavior of the fuel heat and mass evaporation transfer progress on hot surface,consider the convective mass transfer and heat transfer, the liquid-gas two-phase flow of continuous heat transfer model was studied. By the dimensionless transform, the time-dependent behavior of the concentration distribution and the temperature field was obtained. The result of n-Heptanes evaporation transfer progress on hot surface experiment is consistent with the academic model.
A Modified Proportional Fair Scheduling Algorithm for the Electric Power Wireless Private Network
Authors: Cao Jin Ping , Liu Jian Ming , Zhu Shao Min , Gao De Quan
Published: December 2012

With the development of smart grid, the requirements of high speed, low delay and better coverage have motivated a electric power wireless network that bridge the communication gaps between the transmission system and the load. In this paper, we introduce a new electric power wireless communication network, and give a general overview of studies on the major characters of communication such as wide coverage, a lot of measurement points in distribution networks as well. In order to improve the communication performance, the paper proposes a modified proportional fair algorithm, which allocates the radio resources by introducing a Quality-of-Service (QoS) scale factor. By comparing with the proportional fair algorithm, we get the conclusion that the modified algorithm is more suitable for the electric power wireless private network.
Survey of Wind Power and Integration Smart Grid Technologies
Authors: Xing Tian Wei , Shen Hong , Ding Jian , Dong Lei , Han Jia Hui , Song Yun Ting
Published: December 2012

Because of the fact that the availability of renewable energy sources is determined by the weather and can hardly or not be affected, new functions of electricity networks are required. Smart grid is inevitable in the development of the renewable energy. In this paper a detailed survey of the smart grid techniques about wind power and integration of wind power was provided. An attempt was also made to identify development trend of the future. This survey will also be helpful for the wind farm and grid owner to understand the current smart grid technologies and will give them an idea that technologies will be suitable for the development of the future.
The Application of Ucosφ Out of Step Criterion to the East China Power Grid
Authors: Fu Hui Min , Gu Dan Zhen , Chen Chun Jie , Yang Xiu
Published: December 2012

This paper analysis the characteristics of two-machine equivalent system in out of step state. According to variation in the out of step state, study the out of step criterion of .Use change area to determine whether the system is out of step, The criterion is simple and clear, and the concept is clear. It can distinguish the acceleration step and deceleration of step, and automatically adapt to system changes in the structure and Operation mode. The minimum voltage amplitude of the device installed is used for capture the oscillation center .The 2012 East China Power Grid, region A fleet out of step mode is simulated analyzed, It is verify that the criterion of accuracy and adaptability in the East China Power Grid.
Optimal Option Analysis of Distributed Generation Equipments
Authors: Zhang Ya Peng , Liu Qing Rong , Ruan Ying Jun
Published: December 2012

In the application of distributed generation technologies, different building have its own heat-to-power ratio, therefore equipment selection is a key point to determine the energy saving ratio. This study analyzes some devices of four different types, from two basic managements, heat-tracking and electricity-tracking. Result shows the optimal heat-to-power ratio of some certain devices and the changing trends were also given out. The energy saving ratio were also calculated.
Flow and Heat Transfer in Microchannels of the MTPV Systems
Authors: Wu Ge Ping , Lu Ping
Published: December 2012

Heat transfer and flow characteristics in the microchannel cooling passages with three different types of the MTPV systems are numerically investigated. This investigation covers Reynolds number in the range of 100 to 1000 and heat flux ranged from 50kW/m2 to 150kW/m2. The steady, laminar flow and heat transfer equations are solved in a finite-volume method. Results such as temperature distribution, heat transfer coefficient, pressure drop and friction factor are reported. A comparison of the heat transfer coefficient and friction factor of the different microchannels are also presented. The heat transfer performance of the rod bundles microchannel is found to be much better than others. Both friction factor and heat transfer coefficient are increased as the Reynolds number increased.
The Research of Subspan Oscillation and Configuration of Spacer for Transmission Line
Authors: Di Yu Xian , Zhu Kuan Jun , Liu Cao Lan
Published: December 2012

Based on the summarization of domestic and foreign experience, the computational method of spacer configuration was developed in order to depress sub-span oscillation principally. The requirements of the reverse recovery characteristics were considered. The computer-aided calculation procedures were programmed. The finite element analysis model of sub-span oscillation for cable-spacer system was established. The inherence modal and amplitude for sub-span oscillation of bundled transmission lines were calculated by using numerical simulation method. The dynamic configurations were analyzed by using the parameters of the cable and spacer obtained from vibration testing.
Air Preheaters Operating Situation and Analysis in Coal-Fired Generators
Authors: Li Ling , Li Min , Zhang Bu Ting , Qiao Kai
Published: December 2012

To prevent and dispose all kinds of problems occurred in the air preheaters of the large coal-fired power plants and improve the performance of the air preheaters, the representative problems of the air preheaters in Henan province was summarized with the statistical method. With specific cases, its adverse impact for boilers and auxiliary machines were analyzed. The main reasons for causing these problems were design flaws, maintain undeserved, poor blowing effect and high sulfur content in coal that can cause acid corrosion to the air preheaters. A series of countermeasures were put forward to resolve the problems.
Power System Wide-Area Situation Awareness
Authors: Luo Wei , Zhuang Wei Jin
Published: December 2012

The definition of the situation awareness and its position and effect in power system is proposed. The main characteristic of situation awareness is described. The functions and realizing ways of the situation awareness are analyzed detailed.
The Research on Preventing Mal-Operation Algorithms in Distribution Network
Authors: Zheng Yan Wei , Ma Liang , Wu Yong , Feng Zhi Quan
Published: December 2012

To analyze the operating orders in distribution network with multi-power supply and prevent mal-operation, the topological analysis algorithm and the logic-based analysis algorithm are proposed in this paper. In the topological analysis algorithm, the procedures of opening and closing breakers, isolating switches, and grounding device are expounded, which are based on the topological information of distribution network. In the logic-based analysis algorithm, the operating orders are analyzed according the collocated logical expressions. It needs abundant of artificial information, but it has strong ability to express. The experimental results show these algorithms can determine the simulating operation orders in short response time.
Abnormal Heat by Thermal Changing in a D-Pd Gas-Loading System
Authors: Lu Xin , Wang Hong Yu , Tian Jian , Jin Li Hong , Shen Bing Jun , Zhao Xin Le
Published: December 2012

In order to explore the condensed phase whether may promote abnormal heating phenomenon and nuclear reactions occur, as well as how to construct and characterization of condensed phase structure filled with deuterium and the use of exogenous trigger transient change. Some deuterium atoms were charged into metal palladium lattice and reached a certain ratio in a D-Pd gas-solid system under the pressure of PD26J heat energy were released in 8 hours, when loading ratio of deuterium x was 0.12, current 8A, pressure 9×104Pa. Improvement of experiment, that excess heat power 41W and 79.58MJ heat energy, which was corresponding to 1.8×104eV for each palladium atom were released in 83 hours and 17 minutes, when current 7.25A, pressure 9×104Pa. An energy dispersive spectrometer (EDS) revealed that new surface topographical features with concentrations of unexpected elements Ag were detected, which implied that the excess heat might come from a nuclear transmutation reaction.
Thermodynamic Analysis and Experimental Investigation of Internal Heat Exchanger Influence on CO2 Trans-Critical Cycle Performance
Authors: Zhang Wen Hui , Wang Zhe , Gong Yi , Wu Xue Hong , Lu Yan Li
Published: December 2012

This work present the experimental evaluation of the energy performance of trans-critical CO2refrigeration and heat pump systems. The optimal gas cooler pressure and the optimal COP have been analysed from a thermodynamic point of view. The experimental evaluation covers five evaporating levels (-10 to 10°C) and in a wide range of gas cooler outlet pressures (75 to 120bar). It is concluded that: With the the internal heat exchanger (IHX) system compressor power is relatively low, when the high side pressure is over 100bar, and the evaporation temperature is below 0°C. The COP of the system without IHX is slightly higher than the system with the IHX, it is increase about 3% to 5%, when the evaporation temperature is over 5°C.
The Numerical Simulation of the Shell Side Flow and Heat Transfer for 600MW Steam Turbine Condenser
Authors: Wang Si Ping , Zhang Li , Li Jian
Published: December 2012

Detailed prediction of steam flow field and heat transfer process is significant for the condensers. The flow and heat transfer performance of the condenser of 600MW power unit is numerical simulated. A model of porous media with distributed resistance and mass sink is used to simulate the function of the tube bundle. The equations including the continuous, momentum and air concentration are numerically solved using the finite control-volume integration method and SIMPLE algorithm. The distribution of steam velocity, pressure, heat transfer coefficient and air concentration are obtained and analyzed. On the basis of results, the condenser is evaluated.
Calculation Method of Attemperation Water Flow in Changing Steam Flow Condition
Authors: Wang Qing , Li Yuan
Published: December 2012

In order to control the attemperation water demand, the superheater heating ability is calculated by enthalpy increment. According to the changed enthalpy of the superheater outlet, the attemperation water demand is estimated. To simplify calculation, the changing steam flow is regarded as linear process during a certain time. Thus, the attemperation water calculation method is obtained. Basis on this, Matlab software is used to perform computer simulation to the system.
Orthogonal Experimental Research on Sintering Cooler Transfer Performance
Authors: Zhao Bin , Wen Zhi Mei , Zhong Xiao Hui , Han Xi Qiang
Published: December 2012

Circular cooler is deployed for sinter cooling process in sintering industry. According to the sinter cooler from HBIS, an experimental study was conducted and a bench of the heat exchange body was built. Under the same initial temperature of the sinter, the experimental results of nine conditions are compared, which reveals the effect of particle size, material thickness, air flow rate and inlet air temperature on sinter sensible heat extraction, adopting orthogonal experimental method. Experiment results show that, at the mixing condition of material thickness 1400 mm, air flow rate 921 m3•h-1 and inlet air temperature 90 °C, the unit of sinter available exergy reaches 313.55 kJ•kg-1. The conclusions provide theoretical and experimental basis for the sensible heat extraction process of the sinter.
Numerical Simulation of the Liquid Flowing and Heat-Transfer outside the Tube of the Horizontal-Tube Falling Film Evaporator
Authors: Hu Wei Kang , Yang Li , Guo Lei Hong
Published: December 2012

This paper mainly studies the falling film evaporator in the field of water desalination. Using the method of fluent simulates the process of the liquid flowing and heat-transfer on the horizontal-tube falling film evaporation. The author analyses the distribution of the liquid film, and obtain the rule that spray density, evaporation temperature, temperature difference and pipe diameter affect the performance of heat-transfer in a certain range. So the paper plays a guiding role in heat transfer enhancement in the falling film evaporator.
Control of Magnesium Alloys Two-Roll Strip Cast Cooling System Based on the Fuzzy Model
Authors: Wang Zhong Chu , Bi Ran , Zhao Xin
Published: December 2012

This paper describes the Fuzzy control of circular cooling water in a twin-roll strip cast, joins a feed-forward compensation to solve the time lag in conveying water. Because of the large time lag, multivariable system and hard modeling, this paper presents a Fuzzy controller for them. Based on the synthesis reasoning rules and Fuzzy logic, the Fuzzy model of circular cooling water is established. Then the simulation results show that the strip can effectively keep a constant temperature. And it has a good tracking performance, robust, strong anti-interference ability, and the cooling water can in time exchange heat with the liquid metal to get high quality strip.
Numerical Simulation Investigations of DRB-4Z Type Dual Channel Swirl Burner Outlet Flow Field
Authors: Mi Cui Li , Fan Xiao Hua , Wei Gang , Zhang Yong Sheng
Published: December 2012

Numerical simulation was used to analyze and calculate the outlet flow field of DRB-4Z type dual channel swirl burner. The results indicate that the recirculation zones become shorter, the diameter of the recirculation zones and the flow divergent angle decrease with the rising of the primary air velocity. Too lower primary air velocity causes the mixing of primary air and secondary air become weaker, which goes against the stable ignition of pulverized coal. With the increase of the outer secondary air blade angle, the flame length increases obviously. The mixing of primary air and outer secondary air is delayed, which decreases the combustion stability. Too small angle of the outer secondary air causes the generation of recirculation zone in the center of flame tail, which has adverse effect on the combustion stability. The attenuation of the highest axial velocity and tangential velocity become faster with decreasing of outer secondary air blade angle.
Running Safety of High-Speed Train Equipped with Aerodynamic Brake under Cross Wind
Authors: Tian Chun , Wu Meng Ling , Zhu Yang Yong , Chen Meng Ting
Published: December 2012

The flow field structure and aerodynamic forces of trains with aerodynamic brake in cross-wind after simplifying the train’s model are studied. Three-dimensional Reynolds average N-S equations (RANS) combining k-ω turbulence model is adopted. The SIMPLE method is used to couple the pressure and velocity. Firstly, the train’s flow field’s variation discipline caused by the aerodynamic brake is analyzed. Then the side force, lift force and rollover moment acting on the train with aerodynamic brake and the one without aerodynamic brake are compared on condition of various wind direction angles. The influence of the aerodynamic brake on trains’ aerodynamic forces and derailment coefficient on condition of various wind direction are analysed. It comes to a conclusion that the derailment coefficient of the train with aerodynamic braking is truly increased but only slightly increased and all the derailment coefficients are under 0.8 which satisfy the safety request of the train’s running safety.
Control Strategies for Safe Diesel Particulate Filter Uncontrolled Regeneration during Idle
Authors: Wang Dan , Liu Zhong Chang , Tian Jing
Published: December 2012

For diesel particulate filter (DPF) drop-to-idle uncontrolled regeneration, a regular regeneration is initiated following a vehicle stop while the engine switches to idle. The increase in oxygen concentration and the decrease in exhaust flow rate can result in a sharp exotherm in the filter and high temperature to damage the substrate. In this paper, control solutions for the idle thermal protection of the filter was proposed and validated experimentally. At high idle speed of 2200rpm, increasing exhaust gas recirculation (EGR) combined with intake throttling was a practical way to reduce available oxygen content to control the exothermal reaction rate. A much lower peak temperature was obtained for safe DPF regeneration during idle. The research would provide based information for optimizing the regeneration management strategy in order to avoid DPF failure in real world operation.
Mechanical Model of Variable Diameter and Screw Pitch for Biomass Screw Feeder
Authors: Tu De Yu , Xu Ai Hua , Wang Xu , Chen Xin
Published: December 2012

On the base of analyzing the parametric design model of the screw feeder with variable diameter and screw pitches, a parametric design model of screw shaft was given in this paper. By choosing biomass material in a pocket between adjacent flights as the study object, the force between bulk material and five contact surfaces were analyzed during the conveying process, and a mechanical model for biomass screw feeders was built up. Meanwhile, a theoretical method to calculate torque of screw shaft with variable diameter and screw pitch was provided. The theoretical method could be also used in calculating torque for screw shaft with unchangeable pitch and diameter.
Optimization of No-Load Voltage Waveform in a Large Hydro-Generator by the Schemes which Shift the Damper Winding and Skew Stator Slots
Authors: Luo Yong Gang , Fan Zhen Nan
Published: December 2012

Improvement of no-load voltage waveform is a important problems for designing hydro-generators and ensuring operation reliability of the generators and electric network. The no-load voltage waveforms of a 335MW hydro-generator are optimized with the design scheme which shift damper winding and skew stator slots, and the computations are implemented and analyzed by the multi-slice moving electromagnetic field-circuit coupling model of the hydro-generator The results show that the waveforms of the no-load voltage are improved observably when reasonable shift damper winding and skewing stator slots. The calculation results are coincident well with the test data. The research is helpful for improving design standard and enhancing the operation reliability of the large hydro-generator and electric network.
Numerical Calculation of Centrifugal Fan 9-19No.4A
Authors: Meng Fan Nian , Dong Quan Lin , Chen Nan , Fan Yun Qiang
Published: December 2012

This paper is to simulate the internal flow field in the impeller and the volute of 9-19No.4A fan under different operating conditions. Based on CFD theory and standard two-equation turbulent model, the simulations of turbulent flow between the impeller and the volute under different operating conditions are performed by using the flow calculation software CFX. Numerical results are utilized to perform detailed flow visualization. The results indicate that the fan performance curve of the experiment agree with those of numerical simulations.
Flow Field Simulation Analysis of the Inner Stack of Coal-Fired Power Plant
Authors: Shi Zhou , Yang Jin Ge , Feng Cai , Wu Jiang , Gao Wen , Li Yan , Chen Jian Hua , Dai Xue Wei , Zhao Li Li
Published: December 2012

The flow field of inner stack of one coal-fired power plant in Shanghai was simulated. The results showed that there was a larger turbulent region at the upper parts of the entrance in the stack. The inner wall at the opposite of the entrance withstands a much greater shock, and this region is badly worn. The speed in the central and upper region is more stable. The stack is basically running in a vacuum state, which contributes to corrosion mitigation. The temperature shows a decrease trend with the increase of height in the range of 10°C. The temperature of the center part is slightly higher than the ambient part. And with the increase of the stack height, the radial temperature gradient increases.
Design and Development of Low Subsonic Wind Tunnel for Turning Diffuser Application
Authors: Nordin Normayati , Abdul Karim Zainal Ambri , Othman Safiah , Raghavan Vijay R.
Published: December 2012

In practice, it is basically difficult even with controlled measurement environment to acquire a steady, uniform and fully developed flow. The flow entering diffuser was severely distorted despite a sufficient hydrodynamic entrance length already introduced. This was mainly due to the imperfect joining of duct and the abrupt change of the inlet cross-section applied. In this study, several basic features of a low subsonic wind tunnel, i.e. a centrifugal blower with 3-phase inverter, a settling chamber, screens and a contraction cone, are designed and developed for a turning diffuser application in order to improve the flow quality. The flow profiles are examined using Pitot static probe at five measurement points within the range of inflow Reynolds number, Rein= 5.786E+04-1.775E+05. The steady, uniform and fully developed turbulent flow profiles with an average deviation with theory of about 3.5% are obtained. This proves that a good flow quality could be produced by means of incorporating some basic features of a low subsonic wind tunnel to the system.
2D CFD Simulation of Hydrodynamics of the Dense Zone of a 65t/h High-Low Bed CFB
Authors: Wang Qing , Xiao Jian Bo , Liu Hong Peng
Published: December 2012

Gas-solid flow behavior of the bottom zone of a 65t/h High-low bed CFB was simulated using the commercial computational fluid dynamics (CFD) software package Fluent. The Eulerian-Eulerian model (EEM) based on the kinetic theory of granular flow (KTGF) was adopted. This approach treated each phase as continuous separately. The link between the gas and solid phases was through drag model and turbulence model. While the turbulence was simulated by the standard k-ε and mixture multiphase model, the Gidaspow drag model was used to model the interphase interaction. Four phases were set to achieve size distribution in the EEM. Gas and solid flow profiles are obtained for solid velocity, solid volume fraction, pressure, and size distribution. The results show that EEM can predict preferably the internal circulation process of the dense zone high-low bed CFB.
Automotive Air-Conditioning Control System Based on the LIN Bus
Authors: Xiong Shu Sheng , Xu Jin , Zhong Fang Mei , Xie Lian , Zhou Sheng Kai
Published: December 2012

This paper describes the control system design based on the LIN bus on car air conditioning. Using the STMicroelectronics STM32 family of 32-bit ARM Cortex M3 core SCM as the controller, a LIN bus application and design in the modern automotive air conditioning control system are proposed, resulting to achieve reliable, stable, simple wiring harness, and low-cost of automotive air-conditioning control system.
Study on Effect of Neutral Grounding Mode on Reliability of Distribution Network
Authors: Dong Lei , He Lin , Li Wei Di , Ao Xiao
Published: December 2012

There exists an optimization problem of neutral grounding mode in distribution network with a large number of cable lines. In order to choose the best grounding mode for distribution network, factors of effect of neutral grounding mode on reliability of distribution network are analyzed. The development process of distribution line's fault under each neutral grounding mode is simulated with Monte Carlo simulation method by MATLAB programming. At the same time, the reliability index is got to evaluate and compare this effect quantitatively. An example is used to prove this method’s rationality and effectiveness.