《电工电能新技术》
· Introduction ·
· Contents ·
2016.1
2015.12
2015.11
2015.10
2015.9
2015.8
2015.7
2015.6
2015.5
2015.4
2015.3
2015.2
2015.1
2014.12
2014.11
2014.10
2014.9
2014.8
2014.7
2014.6
2014.5
2014.4
2014.3
2014.2
2014.1
2013.4
2013.3
2013.2
2013.1
2012.4
2012.3
2012.2
2012.1
2011.4
2011.3
2011.2
2011.1
2010.4
2010.3
2010.2
2010.1
2009.4
2009.3
2009.2
2009.1
2008.4
2008.3
2008.2
2008.1
2007.4
2007.3
2007.2
2007.1
2006
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2003
· Abstracts ·
2016.1
2015.12
2015.11
2015.10
2015.9
2015.8
2015.7
2015.6
2015.5
2015.4
2015.3
2015.2
2015.1
2014.12
2014.11
2014.10
2014.9
2014.8
2014.7
2014.6
2014.5
2014.4
2014.3
2014.2
2014.1
2013.4
2013.3
2013.2
2013.1
2012.4
2012.3
2012.2
2012.1
2011.4
2011.3
2011.2
2011.1
2010.4
2010.3
2010.2
2010.1
2009.4
2009.3
2009.2
2009.1
2008.4
2008.3
2008.2
2008.1
2007.4
2007.3
2007.2
2007.1
2006
2005
2004

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《电工电能新技术》2016年第1期目录
第35 卷第1 期(总第151 期)  2016 年1 月
目  次

论文报告
IRP 理论和IEEE Std 1459⁃2010 在变流器驱动电机能效测试中的应用比较
 ...

  2015.9

2015.9
  日期:2015-09-23     【背景色 杏仁黄 秋叶褐 胭脂红 芥末绿 天蓝 雪青 灰 银河白(默认色) 】  【字体:
 

Mathematical analysis on saddle waveform PWM based
on isosceles triangle carrier wave
CHEN Guo⁃cheng1,2, CAI Li⁃qing, ZHOU Qin⁃li, GU Hong⁃bing, LEI Dian1,2
(1. Giant Industry Technology Co. Ltd. , Changzhou 200122, China;
2. Department of Automation, Shanghai University, Shanghai 200072, China)
Abstract: This paper aimed at clarifying the prevalent point of view that the SVPWM is identical to the SAPWM,
the optimization method of SAPWM is explained in detail, and the excellent results of SAPWM are easy to be dis⁃
cerned. SVPWM is not SAPWM, it uses the concept of space voltage vector, and SAPWM is a special case of SVP⁃
WM. In the pattern optimization process of SAPWM, it is found that when the upper and lower envelope modulation
sine waves are symmetrical in the horizontal coordinates, the optimum output characteristics can be obtained, and
its meaning is very clear in geometry as well as physical. Owing to the inherent characteristics of SAPWM, when
the output voltage is identical, the required depth of modulation is smaller than SPWM, such that there are more
difference frequency waves in carrier wave frequency domain. However, compared with SPWM, the amplitude of
difference frequency waves is smaller, so the total harmonic distortion and total harmonic loss are reduced to some
extent, and the positive and negative sequence components of the cogging torque generated cancel each other, that
effectively suppresses the torque pulsation. SAPWM can further raise the modulation depth, and help to improve
the DC bus voltage utilization, thus becoming an optimal modulation pattern used in three⁃phase inverter. On the
basis of SPWM mathematical analysis, we made thorough analysis with the use of the Fourier series expansion meth⁃
od for SAPWM, demonstrated the proofs that make SAPWM the optimal modulation pattern. Mathematical analysis
of this paper is simpler compared to other analytical methods, clear and easy to understand, and a lot of derivation
workload can be saved. Key words: inverter; pulse width modulation; harmonics; torque ripple; spectrum; space voltage vector

Broken rotor bar fault diagnosis of induction motors
based on p⁃q transform
XU Dong⁃li, CHENG Gui⁃lin, HOU Xin⁃gui, LI Chao⁃sheng
(School of Power Engineering, Nanjing Institute of Technology, Nanjing 211100, China)
Abstract: The rotor bar breaking fault was one of the common faults of induction motors. When the bar is broken,
the frequency components of the fault feature will appear in the stator current. Compared with the amplitude of the
fundamental frequency component they are very small. In the analysis, they will often be overwhelmed by the leak⁃
age of fundamental frequency, especially in the case of low load rate when the motor is running. To solve this prob⁃
lem, the paper proposes a new method for broken rotor bar fault diagnosis of induction motors based on p⁃q trans⁃
form, which can remove the fundamental frequency component from stator current, so that the characteristic fre⁃
quency components can be highlighted to achieve the detection and diagnostics of rotor bar breaking fault. The the⁃
oretical analysis and experimental verification indicate that the method of fault detection and diagnosis for induction
motor is able to correctly detect the rotor bar breaking fault of induction motors, even when the motor is running at
low load rate and it also gives out a good detection results.
Key words: induction motor; broken rotor bars; p⁃q transform; fault diagnosis; MCSA

Accurate estimation of SOC value of electric vehicle battery based on
EKF algorithm optimized by BP neural network
RONG Ya⁃jun, YANG Wei, NIU Huan, ZHENG Xin⁃hui
(Key Lab of Power Electronics for Energy Conservation and Motor Drive of Hebei Province,
School of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China)
Abstract: In this paper, DSP (TMS320LF2407) is used as the main chip to complete the electric vehicle battery
management system platform structures. The battery state of charge (SOC) precision estimation is one of the core
tasks of electric vehicle battery management system. To improve the estimation accuracy of SOC, BP neural network
method based on extend Kalman filtering (EKF) is put forward. The BP⁃EKF is a kind of new algorithm. After the
lithium iron phosphate (LiFePO4) battery is fully tested and analyzed, BP neural network is established by using
artificial neural network toolbox of MATLAB, and the BP neural network was trained using the experimental data
and the parameters optimization to expand the Kalman filter algorithm. The development of Kalman filter method is
used for battery SOC estimation. Simulation results verify the accuracy of the two algorithms. The results show that,
compared with the EKF filtering, this method is simple, and the accuracy of BP⁃EKF algorithm for SOC estimation
is improved significantly. The method has good applicability. Key words: state of charge; battery management system; BP neural network; extend Kalman filtering

Coordinated planning of multi⁃type electric vehicle charging stations
based on maximal entropy theory
WU Jian⁃sheng1,2, LI Xiao⁃zhou
(1. Key Laboratory for Environmental and Urban Sciences, Shenzhen Graduate School, Peking University,
Shenzhen 518055, China; 2. Key Laboratory for Earth Surface Processes, Ministry of Education,
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China)
Abstract: The paper presents a planning method of electric vehicle charging stations based on the maximal entropy
theory. The distribution entropy of electric vehicle is firstly defined to describe the coincidence between the location
of charging stations and charging load based on different characteristics of multi⁃type electric vehicle charging sta⁃
tions. Then the multi⁃type electric vehicle charging stations planning model is established based on a multi⁃objec⁃
tive method. And after defining the desirability function of each objective, the genetic algorithm is applied to seek
the solution. Finally, the planning model is applied in a 25 node road network to testify the method presented in
this paper and the results are compared with that of the method in which only investment income is considered as
the objective. Results of the method in this paper show that the proportions of charging stations distribution are rela⁃
tively close, which indicates better coincidence between the distribution of electric vehicle charging stations and
charging load.
Key words: electric vehicle, charging station planning; charging mode; maximal entropy

Harmonic detection of power grid based on multiple second
order generalized integrators
LI Lian⁃bing, GUO Xiang⁃shang, WANG Zeng⁃xi
(School of Control Science and Engineering, Hebei University of Technology, Tianjin 300130, China)
Abstract: To ensure the synchronism between the grid⁃connected power converter and grid, in case of three⁃phase
power grid voltage becoming imbalance or containing low⁃order harmonics, a frequency⁃adaptive synchronization de⁃
tection method was presented. This method is based on a decoupled network consisting of multiple second order
generalized integrators (MSOGI) which are frequency⁃adaptive by using a frequency⁃locked loop (FLL). Mean⁃
time, the cross⁃feedback network is applied to decouple the multiple harmonics and the equivalent filtering is used
to individually detect the fundamental or each harmonic component in real time. The positive⁃ and negative⁃se⁃
quence components of the power signal at the fundamental frequency can be detected, and other sequence compo⁃
nents at multiple frequencies can also be detected. The simulated results show that the MSOGI⁃FLL is a very suit⁃
able solution to detect fundamental⁃frequency positive and negative sequence components of unbalanced and distort⁃
ed grid voltages, and exhibits a better static and dynamic performance.
Key words: frequence locked loops; multiple second order generalized integrators; harmonic component detection;
cross⁃feedback network

Research on early detection of short⁃circuit fault in multi⁃level
low voltage system
WU Xiao⁃mei, MIAO Xi⁃ren
(College of Electrical Engineering and Automation, Fuzhou University, Fuzhou 350108, China)
Abstract: Based on the necessity and research status, an early detection method for short⁃circuit fault is proposed
by a detail component of wavelet packet decomposition so as to fulfill the requirement of the full range selective and
coordinative protection in a multi⁃level low voltage system. A three phase short⁃circuit fault model is established to
verify the validity of above method with full range of phase angle in a low voltage system, which overcomes the lim⁃
its of wavelet transform in robustness of individual initial angle region in short⁃circuit fault early detection. Second⁃
ly, according to the current singularity for load starting processing and short⁃circuit fault, the start and fault are i⁃
dentified agilely by early detection in full range angle after short⁃circuit fault 0􀆰 1ms. Finally, by analyzing the early
detection characteristics of relevant branches for fault point, an early detection identification mechanism for accurate
pinpointing of short⁃circuit fault branch is expounded. The research of this paper lays a theoretical foundation for a
novel short⁃circuit fault selective and coordinative protection in a multi⁃level low voltage system. Key words: low voltage system; short⁃circuit fault; multi⁃level selective protection; early detection; wavelet pack⁃
et decomposition

Basic design principles for micro⁃grid architecture
ZHU Yong⁃qiang, JIA Li⁃hu, WANG Yin⁃shun
(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,
North China Electric Power University, Beijing 102206, China)
Abstract: Micro⁃grid architecture design is the basis of the micro⁃grid construction. It is necessary to follow certain
design principles when designing micro⁃grid, which differs from traditional distribution network designing. Based on
the detailed analysis on the advantages and disadvantages for AC microgrid and DC microgrid, it is pointed out that
the AC/ DC hybrid microgrid has the advantages both of them, and it can be a good solution to the problem of dis⁃
tributed energy connected to a distributed network. This paper describes several micro⁃grid structure design princi⁃
ples, taking into consideration of the partition and hierarchical principle, as well as maximization of resource utili⁃
zation, energy complementary, energy storage and reactive power compensation. It also proposes the solutions when
the resources and load conditions cannot meet the design principles. Finally, this paper designs a microgrid archi⁃
tecture for a university of Beijing to verify the rationality and feasibility of the above design principles. Key words: micro⁃grid; AC⁃DC hybrid; architecture design; design principles

Application of planar LC unit with integrated three
parameters in switching power supply
GONG Min, WANG Shi⁃shan, SONG Zheng
(Jiangsu Key Laboratory of New Energy Generation and Power Conversion, Nanjing
University of Aeronautics and Astronautics, Nanjing 210016, China)
Abstract: The model composed of ‘induction’ and ‘capacitance’ (‘LC’ unit) is an important component of EMI
filter and it can integrate different parameters with different connection modes. In order to improve the characteris⁃
tics of common mode filter, a new LC unit which realizes the integration of common mode inductor (LCM), differen⁃
tial mode inductor (LDM ) and differential mode capacitor (CDM ) is presented in this paper. When the common
mode current is entering, the capacitance effect can be ignored since the upper and lower coils are completely sym⁃
metrical, and finally the LC unit can be equivalent to two parallel coil; when the differential mode current is ente⁃
ring, the effect of inductance can be ignored since the voltage distribution of the inductor is zero. Similarly, the LC
unit can be equivalent to a capacitor. Based on the analysis of the coupling modes, the equivalent circuits are given
in this paper. Meantime, the dislocation connection technology is adopted to complete the EMI filter. Finally, the
LC unit which is connected by the new way will be used in the low power PFC supply. The effectiveness and the su⁃
periority of the new structure are verified by experiment.
Key words: LC unit; differential mode current; common mode current; low power PFC circuit

Design of impedance conversion network employed for capacitive
coupled wireless power transmission system
CHEN Xi⁃you, WU Hong⁃xia, MU Xian⁃min, ZHAO Ning
(1. School of Electrical Engineering, Dalian University of Technology, Dalian 116024, China;
2. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China)
Abstract: A stage by stage design principle of impedance conversion network (ICN) for capacitively coupled wire⁃
less power transmission is proposed in this paper. By this method, first of all, the needed equivalent resistances of
each ICN are determined according to the power supply, load resistance and its power, as well as the permissible
coupling capacitor voltage. Using these equivalent resistances, the analytical formulas to design the inductance and
capacitance of the ICN are then obtained. A larger equivalent resistance is obtained through the ICN in the side of
load. Therefore, the power can be transferred to the ICN by means of low current and high voltage. Not only the
coupled capacitor voltage is reduced, but also the power losses caused by series resistor of the inductor and the ca⁃
pacitor are slowed down. An actual ICN for low power application is designed using proposed method. Correctness
and effectiveness of the design principle are verified by both simulation and experimental results.
Key words: wireless power transmission; capacitively coupled; impedance conversion; network design

Effect of reactive power and voltage characteristics on cascading failures
LIU Wei, HUANG Shao⁃wei, YAO Rui, LEI Jun⁃zhe
(1. Henan Province Electric Power Research Institute, SGCC, Zhengzhou 410100, China;
2. State Key Lab of Control and Simulation of Power Systems and Generation Equipment,
Department of Electrical Engineering, Tsinghua University, Beijing 100084, China)
Abstract: Cascading failures and blackouts in real power systems indicate important role of reactive power and volt⁃
age profile in cascading failure process. To study the effect of reactive power and voltage on cascading failure, cas⁃
cading failure models based on AC power flow (AC⁃CFM) and DC power flow (DC⁃CFM) are established respec⁃
tively. The two models are similar in procedure and related dynamics modeling. The models can be used to simulate
cascading failures with same system data, and then to analyze the effect of reactive power and voltage profile by
comparing cascading failure characteristics and risk metrics. The two models are tested on IEEE⁃30 test system and
Henan provincial grid system, and the results suggest that reactive power and voltage profile have significant impact
on the last phase of cascading failure development as well as risk metrics, in the meantime, the risk of voltage col⁃
lapse brought by cascading failure cannot be neglected. Key words: cascading failure; reactive power and voltage; risk assessment; voltage collapse

Detection of insulator contamination grades based on digital image processing
TIAN Zhi⁃ren1,2, JIN Li⁃jun
(1. College of Electric and Information Engineering, Tongji University, Shanghai 201804, China;
2. State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an
Jiaotong University, Xi’an 710049, China)
Abstract: A new method is presented, using digital images of high voltage insulators to detect the contamination
grades. Firstly, we obtain the sample digital images from the transformer substations in Shenzhen City by taking
photos of insulators with different contamination grades and their ESDD (equivalent salt deposit density) respective⁃
ly. Secondly, after graying, enhancing and denoising, we obtain the polluted area of an insulator with two times of
OTSU image threshold segmentation method. Thirdly, we visit 36 characteristics from RGB and HSV space, and
with the help of Fisher criterion, we extract the features that can reflect the characteristics of insulator contamination
grades. Finally, we train a BP neural network with the extracted features, whose accuracy rate is 88% in detecting
the contamination grades of sample images. The experimental results show that this method is feasible for detecting
the contamination grades of high voltage insulators, which may provide some engineering significance for insulator
cleaning and flashover prevention.
Key words: insulators; contamination grades; digital image; OTSU; Fisher criterion; BP neural network

Optimization of RF coil in single⁃sided NMR system
JI Yong⁃liang, HE Wei, WU Gao⁃lin, WANG Qian
LI Long, MENG Kai⁃kai, XU Zheng
(1. Electric Power Research Institute of State Grid Chongqing Electric Power Company,
Chongqing 401123, China; 2. State Key Laboratory of Power Transmission Equipment &
System Security and New Technology, Chongqing University, Chongqing 400044, China)
Abstract: RF coil is used to transmit and receive signals in nuclear magnetic resonance (NMR) system, whose
performances largely determine the signal quality. By considering the low signal⁃to⁃noise ratio (SNR) of single⁃si⁃
ded NMR system, we optimized the planar rectangular spiral RF coil based on its spatial uniformity and SNR. The
optimization method was divided into two steps. ① The optimization goal was based on the uniform area of the RF
magnetic field. We changed the structure parameters of the planar rectangular spiral RF coil. The RF field was cal⁃
culated by Biot⁃Savart Law. The structures of RF coils, which fit the uniform area of the main magnetic field, were
determined. ② The optimization goal was the coils’ SNR. The AC resistance of the coils gained in step ① was
found by the finite element simulation software. Thereby, these coils’ SNR was obtained. At last, a coil, which
has a high SNR in sensitive area, was selected. The result shows: the final RF coil has a wiring area of 17􀆰 2mm ×
17􀆰 2mm and 10 turns, with 5 turns on each face of a 2mm thick printed circuit board (PCB). The lead width and
the adjacent distance are both 0􀆰 5mm. This coil not only has a sensitive area which fits the uniform area of the
main magnet, but also possesses a high SNR from the SNR measurement experiment.
Key words: single⁃sided NMR; RF coil; spatial uniformity; SNR

 


 
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