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Abstracts of Vol.25, Issue 4, 2006
Study on development strategy of petroleum supplement and substitute energy sources for medium-term and long-term in China
YAN Lu-guang, CHEN Jun-wu, ZHOU Feng-qi, ZHAO Zhong-xian, ZHAI Guang-ming, XIE Ke-chang, KUANG Ting-yun, HE Zuo-xiu, YI Bao-lian, WU Cheng-kang, CAI Rui-xian, CHEN Yong, BAI Ke-zhi, MAO Zong-qiang, OUYANG Ming-gao, LIU Zhen-yu, HUANG Chang-gang
(Chinese Academy of Sciences, Beijing 100080, China)
Abstract: The development of supplement and substitute energy sources for petroleum has great significance for fulfilling the ever increasing petroleum requirement and assuring national energy security. The Chinese Academy of Sciences recently organized academicians and specialists to study medium-term and long-term energy sources development strategy in China. Petroleum resource in China is investigated. The requirement and production capacity are predicted. Necessity to develop supplement and substitute energy sources is described. Developing substitute fuel and exploitation of unconventional petroleum is studied. Progress and prospect of using coal, natural gas and biomass as fuel are also studied. In the field of transportation, development of energy-saving composite transportation system, electric railway traffics, energy saving and fuel substitute and electric vehicles and progress and prospect of fuel cell and power batteries are also investigated. Conclusions and suggestions are also presented.
Key words: medium-term and long-term energy sources development strategy in China; petroleum supplement; substitute energy sources; saving oil vehicles; biomass;
A superconducting Magnet with Center Field of 10 T and 100 mm Warm Bore
Q. Wang1, L. Yan1, B. Zhao1, S. Song1, Y. Dai1, Y. Lei1, H. Wang1, H. –C. Huang2
(1. Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100080, China;
2. Diamond Light Source, Ltd., Diamond House Chilton Didcot OXON OX11 0DE, UK)
Abstract: A conduction-cooled superconducting magnet with central field of 10T and warm bore of 100 mm was designed based on a Nb3Sn and two NbTi superconducting coils. At the first stage, the NbTi coils have been fabricated and tested. A two-stage 4 K Gifford-McMahon (GM) cryocooler with the second-stage power in 1W, 4.2K is used to cool the magnet from room temperature to 4 K. The superconducting magnet with the same power supply has the operating current of 116A. The magnet can be rotated with a support frame to be operated with either horizontal or vertical position. A pair of Bi-2223 high temperature superconducting current leads was employed to reduce heat leakage into 4.2K level. The NbTi coils reach to the operating current of 120A without training effect to be observed during charging of the magnet during 40 minutes charging time and generate the center field of 6.5T. The training effect in the NbTi magnet directly cool-down by cryocooler and inter-winding support structure in magnet can be remarkably improved. The superconducting magnet has been stably operated for more than 275 hours with 6.5T. In this paper, the detailed design, fabrication, stress analysis and quench protection characteristics are presented.
Key words: conduction-cooled superconducting magnet; FEA detailed model; training effect
Radial displacement sensorless operation of PM type bearingless motor
NIAN Heng, HE Yi-kang
(College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China)
Abstract: On the basis of analyzing the linear relation between the inductance of suspension winding and rotor radial displacement, a rotor radial displacement estimation scheme using high frequency signal injection in the suspension winding was suggested, which will meet the need of displacement-sensorless operation for a PM type bearingless motor. The rotor radial displacement detecting principle, such as the injection of high-frequency carrier signal, the differential voltage extraction in the suspension winding, the design of the tracking observations for rotor radial displacement estimation, and their implementation technique were all discussed. And then, the displacement sensorless control system of PM type bearingless motor was set up based on this radial displacement estimation approach. Simulation study demonstrates that the proposed method is capable of precisely estimating the rotor radial displacement in the full speed regions for a PM type bearingless motor and is able to achieve stable sensorless suspension operation.
Key words: PM type bearingless motor; radial displacement sensorless operation; high-frequency signal injection; the differential voltage extraction
Study on high-power high-frequency switching electroplate power supply based on digital control
HAO Rui-xiang, ZHENG Qiong-lin, LI Zhong-qiao, LI Kai
(School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China)
Abstract：In this paper, the digital control of high-power high-frequency switching electroplates power supply is realized with DSP (Digital Signal Processor) TMS320LF2407A, and the system design of main circuit and PWM digital control technique of phase-shift full-bridge converter are investigated. The supply is designed with module structure, and different module communicates with each other through CAN (Controller Area Network) bus. This design style makes it easy to realize N+1 redundancy structure, and enhance flexibility and reliability of supply system. To validate the effectiveness of the proposed control methods in this paper, three-12V/1000A shunt-connection high-frequency switching electroplate power supplies are built and experimental results show that the supply is of good control performance.
Key words: electroplate power supply; digital control; phase-shift full-bridge soft-switch; redundancy
Application of particle-group and neural network hybrid algorithm in fault diagnosis
of three-phase rectification circuit
CAI Jin-ding, FU Zhong-yun
（Electrical Engineering and Automation College of Fuzhou University, Fuzhou 350002, China）
Abstract: The application is based on particle-group optimal algorithm and neural network in fault diagnosis of power electronic rectification circuit. First the article discusses the particle-group optimal algorithm and operational procedure to the hybrid algorithm of particle-group and neural network, then the diagnosis method is applied to fault diagnosis of power electronic rectification circuit. According to the simulation result, the hybrid algorithm can be used to the fault diagnosis of three-phase rectification circuit. It has the faster rate of convergence and greater diagnosis accuracy, and it is suitable for practical applications.
Key words: particle swarm optimization algorithm; artificial neural network; fault diagnosis
Design of over-voltage filter at PWM inverter output terminals
GAO Qiang, MA Hong-fei, XU Dian-guo
(Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: The voltage at motor terminal would be double because of the effects of cable distributed parameters when motor is fed with PWM inverter through a long cable therefore resulting in a heavy stress on motor. In this paper, an improved passive filter structure installed at inverter terminals is proposed on the basis of analyzing the relationship of the rising time and the length of cable. The principle for the selection of parameters and detailed design procedure are given. The over-voltage at motor terminal could be mitigated symmetrically by the proposed filter. The validity of the proposed filter is supported by the experimental results which is taken on a 380V/3KW motor system.
Key words: PWM inverter; over-voltage; voltage reflection; filter
Artificial fish school algorithm for optimal power flow problems
LIU Yao-nian, LI Ying-hong, ZHANG Bing-bing, LI Chun-liang
(School of Electrical Engineering, Northeast Dianli University, Jilin 132012, China)
Abstract: A new algorithm is presented to solve OPF problem using AFSA technique in this paper. Incorporation of non-stationary assignment penalty function in solving OPF problem can significantly improve the convergence and accuracy of AFSA. The proposed AFSA method is demonstrated and compared with PSO approach and GA approach on the standard IEEE 30-bus system. The investigations reveal that the proposed method is efficient in solving OPF problem.
Key words: artificial fish school algorithm (AFSA); non-stationary multi-stage assignment penalty function; optimal power flow(OPF)
Comprehensive analysis and design for one cycle controlled DC side APF
WANG Yu-bin, LI Ji-wen, TIAN Zhao-guang, LV Yan
(Shandong University, Jinan 250061, China)
Abstract: One-cycle control (OCC) theory is widely used in the control of APF because of its simple structure and free of complex digital computing process. The DC side active power filter(APF) is shunted at the DC side of rectifier bridge, which has great technical advantages in harmonic suppressing for rectifier load. The circuit topology and basic principle of DC side APF by OCC are first analyzed, then the estimated formulas and design to determine the main circuit parameters, such as the APF inductor, the DC side capacitor of APF, are given in this paper. The large signal model for DC side APF is derived based on energy balance, then the design for PI controller about APF’s control system is accomplished, and the control system is corrected to be typical type II which can eliminate the steady error and improve the anti-disturbing ability. The paper gives the theoretical basis to comprehensively design the DC side APF. The theoretical analysis and design are verified by prototype experiments．
Key words: one-cycle control; DC side APF; PI controller; parameter design
Damping competition and damping coordination of additional excitation control
in multi-machine power systems
HAO Zheng-hang, CHEN Zhuo, DAI Pei-pei, XU Ke-ming
(Department of Electrical Engineering, Guizhou University, Guiyang 550003, China)
Abstract: Based on the conception of general damping of multi-machine power systems, it is proved that additional excitation control does not increase general damping of power systems. When AVR is added to other signals, such as speed, angle, active power, et al., power systems have equal general damping. Because total amount of all the modes’ damping is a constant that does not change on any conditions of additional excitation, damping competition will happen in the course of designing additional excitation rule. The essence of additional excitation control is only a coordinate strategy, and maintaining damping equilibrium among all the modes’ is the real subject. The phenomenon of damping competition indicates that when a mode’s damping is added, another mode’s damping will be reduced. So an excitation rule designer’s work is seeking for a compromise idea which makes all of the modes’ damping reasonable. And a designer must realize that the attempt to increase every mode’s damping is not always available.
Key words: power systems; excitation control; damping competition; damping character; small-signal stability
Short-circuit current forecast application of big electrical network based on improved BP Artificial Neural Network combined with Genetic Algorithm
LIU Bo, ZHANG Yan, CHEN Yu
(Shanghai Jiaotong University, Shanghai 200240, China)
Abstract: In recent years, with the rapid growth of power load and network expansion, the problem of short circuit currents has become significant for the planning and operation of the power system. This paper analyzes in detail the short-circuit current situation as well as the development tendency in our country, proposes a new algorithm to forecast the three-phase short circuit current on the basis of Genetic Algorithm and improved BP Artificial Neural Network Algorithm. Taking a wide range electrical network as an example, the three-phase short-circuit current computation based on load flow is implemented. To find some weak points of short-circuit current level, two algorithms are used to carry out short-circuit current level forecast for those weak points. The feasibility and validity of the method proposed are shown by the simulation and computation. The forecast results provide scientific basis for decision-making for the power sector in the planning and construction of power grids which need some measures to limit the short-circuit current in time.
Key words: short-circuit current; genetic algorithm; improved BP artificial neural network; forecast
Influence of non-ideal hall sensor signals on performance of doubly salient motor
QIN Hai-hong1, ZHAO Chao-hui2, WANG Hui-zhen1, YAN Yang-guang1
(1. Aero-Power Sci-tech Center, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
2. Henan Agricultural University, Zhengzhou 450002, China)
Abstract: Hall sensors are commonly used in doubly salient motor for its simple structure and easy-to-use characteristics. However, requirements on installing accuracy of hall sensor, machining accuracy of rotor tooth for hall sensor, and signal delay characteristics of hall sensor will cause the non-ideal hall sensor signal problem, which adds the difficulty of adjusting hall sensor to optimum position, and impacts the operation performance of the motor, also the motor cannot operate normally. The analysis on this problem is detailed, with the proposed solutions to the engineering problem. At last, experimental results from a 12/8-pole hybrid excitation doubly salient motor verify the correctness and practicability of the solutions.
Key words: doubly salient motor; hall sensor signal; non-ideal; rotor tooth; signal delay
Available transfer capability calculation using particle swarm optimization algorithm
GUO Yuan-fan, YANG Feng, DONG Zhao-xia
(College of Hydropower and Information Engineering in Huazhong University of Science and Technology, Wuhan 430074, China)
Abstract：In power market environment, available transfer capability (ATC) is an important measure to evaluate the electric power exchange among areas in a reliable manner. To solve the problem, some novel methods based on optimal power flow (OPF) were proposed. This paper presents the solution of the available transfer capability (ATC) using particle swarm optimization (PSO) technique based on optimal power flow (OPF). A mathematical model for the calculation of ATC, which considers incorporation of non-stationary penalty function in solving OPF problem, was established. The model can significantly improve the convergence and obtain more accurate values. The proposed PSO method is demonstrated and compared with conventional OPF approach on the standard IEEE 30-bus system. The results show its high efficiency and promising practical applications.
Key words: available transfer capability (ATC); optimal power flow (OPF); particle swarm optimization (PSO)
A new control method for parallel single-phase DC/AC inverter
LIANG Bin, QU Wen-long
(State Key Lab of Power System, Dept. of Electrical Engineering, Tsinghua University, Beijing 100084, China)
Abstract: This paper introduces a new kind of control method for parallel single phase DC/AC inverter. This control method includes two important parts, synchronization control and current sharing control. Synchronization control adopts the method of regulating phase by active power, and current sharing control adopts the method of regulating amplitude by injected harmonic wave. This new method that realized the current sharing without interconnection is suitable to the paralleled power modules that are separated by long distance. This paper describes the new method in detail, and simulation and experimental results are presented. The results demonstrated that the new method is valid.
Key words: single inverter；parallel；synchronization control；current sharing control
Voltage control of permanent-magnet/reluctance generator
WU Yi-yong, SUN Xu-dong, CHAI Jian-yun
(State Key Lab of Power Systems, Dept. of Electrical Engineering, Tsinghua University, Beijing 100084, China)
Abstract：The terminal voltage of a common permanent-magnet generator varies with its rotating speed and load due to its constant permanent-magnet flux, which resulting in unstable quality of power supply. In this paper, based on the equivalent phasor diagram of permanent-magnet/reluctance generator in steady-state condition, a new voltage control method for such a generator is proposed. The terminal voltage amplitude of the generator is maintained to be constant by an electronic power converter connected in parallel with the generator to compensate the reactive current required by its excitation. The structure of the generator system, the compensation principle, the mathematical model of the generator, and the closed-loop system of voltage control method are introduced in the paper. Simulation results verify that the terminal voltage amplitude can be held invariable by using the proposed voltage control strategy when the rotating speed and the load vary in a certain range. Besides, the compensate current is small.
Key words: permanent-magnet/reluctance generator; voltage control; inverter
Influences and suppression method of transformer winding capacitance
in high-frenquency high-voltage flyback converter
ZHAO Zhi-ying, QIN Hai-hong, GONG Chun-ying
（Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China）
Abstract：High-frequency operation of flyback converter has made it clear that parasitic components associated with power transformer have great influences in the behavior of the converter. Leakage inductance and stray capacitance are two major parasitic components. But the latter has received little attention in designing transformer. Winding capacitance plays more important role in the real working of the high-voltage converters and should be taken into consideration. First, a relative simplified transformer model is given through comparison of existing models. And for different applications, this basic model is further simplified for convenience in the engineering analysis. Then for high input voltage and low output voltage applications, effects of parasitic winding capacitance on the operations of high-voltage, high-frequency flyback converter are analyzed with design guidelines deduced. At last, some experimental results are given, which verify the correctness of analysis and practicability of proposed suppression method.
Key words：stray capacitance; flyback converter; high-frequency high-voltage; slope compensation
Research of GE smallworld GIS based outage analysis system
KUANG Hong-hai, XIAO Shen-ping
(College of Metallurgy, Hunan Polytechnic University, Hunan Zhuzhou 412000, China)
Abstract: This paper presents the outage analysis system based on geographic information system (GE Smallworld GIS). Outage analysis system is the tool for creation and maintenance of the feeder connectivity model which traces the electric connection from substation to the customer. Outage analysis system can serve as the graphical point for information on the distribution networks. It makes outage analysis and analog outage analysis real-time display in GIS map. The GE Smallworld GIS based outage analysis is a decision support tool for distribution network operators and provides them excess amounts of data quickly. Outage analysis system may interact with other utility information systems in an integrated environment, and it is the key of the integrative outage management system for distribution network. The study indicates this system is very good in an practical application. It has good performance on outage management.
Key words: GE Smallworld GIS; outage analysis; outage management
Application of Bluetooth wireless technology on power quality monitoring system
YAN Tao，WANG Shu-min
(Tsinghua University, Beijing 100084, China)
Abstract: In conventional power quality monitoring system, the RS232 and Fieldbus technology are used widely to transfer data. And this kind of wire connected technology is limited in some circumstances where cables are not convenient to use. The paper proposed a solution of power quality data acquisition system based on bluetooth technology. Combined with PDA it can measure and display the real-time power quality data in industrial fields. This solution has several advantages such as flexibility, mobility, cost reduction on system installation and strong anti-jamming ability. And the application showed it has the prospective future.
Key words: power quality monitoring systems; single chip; BluetoothTM; BlueCore; PDA; eV
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