Table of Content

15 September 2014 Volume 27 Issue 9

  

Articles

The Shot Boundary Detection Algorithm Based on Random Projection

CAO Yingxin,ZHANG Xiong

. 2014, 27(9):  1. 

Abstract ( 828 )   PDF (677KB) ( 689 )  

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The existing shot boundary detection algorithm exist the problem that the detection accuracy and the detection time are difficult to balance.The finer the extracted features of the video frames,the finer the accuracy will be while at the cost of increased computational complexity and detection time.Inspired by the compressed sensing theory,an improved shot boundary detection algorithm is proposed in this paper in which the random weighted sums of the extracted features were calculated through the random projection.Experimental results show that the proposed method can preserve the detection accuracy well and reduces the complexity and detection time at the same time.

An Adaptive Algorithm for Infrared Image Contrast Enhancement

MENG Yang,HAN Yonggang

. 2014, 27(9):  5. 

Abstract ( 771 )   PDF (744KB) ( 593 )  

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A new approach to the problem of infrared image contrast enhancement is proposed.First,the redundancy of histogram is removed and grayscale range is extended by linear stretch.Then,combined with the platform histogram and bi-histogram equalization,the image is divided into two parts through minimum error threshold method and platform equalization is used in each part.The histogram logarithmic transformation is adopted instead of platform threshold selection to enhance adaptability of the algorithm.The experimental result shows that this algorithm has good effect and fully adaptability so that it is applicable to a variety of infrared images.

Detection of Moving Objects Based on Color Auto-correlogram and Edge Detection

QIAO Yulong,YUAN Kailong

. 2014, 27(9):  8. 

Abstract ( 869 )   PDF (1180KB) ( 806 )  

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The paper proposes an algorithm for the detection of motion objects based on the integration of color features extraction and image edge detection.The color auto-correlogram is used for modeling the features for the images,and the similarities of the detection are compared to obtain the coarse results.Then the edge information is extracted through the Canny edge detection operator with the difference of the consecutive frames binarized to obtain the coarse edge results of the objects.The final results stand out after the morphology operation.The experiments indicate the efficiency of the algorithm for the motion detection in complex environments.

Research on Blind Equalization Algorithm in MIMO Systems

CHEN Xu

. 2014, 27(9):  13. 

Abstract ( 643 )   PDF (781KB) ( 581 )  

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With greater data rate,the MIMO channel becomes to be frequency selective,with serious inter-symbol interference at the receiving end caused by the multi-path and multi-user interference.The blind equalization technology can eliminate inter-symbol interference effectively.This paper focuses on the constant modulus blind equalization algorithm (CMA) in MIMO communication system and proposes an improved algorithm based on sigmoid function.Different from traditional methods,the proposed algorithm based on variable step size can change its step with the convergence of the equalizer.The simulation result shows that the algorithm has a better ability to control the noise and at higher convergence speed.

Robust H_∞ Filtering for Discrete Markov Jump System

WANG Hongru,LIU Shike

. 2014, 27(9):  16. 

Abstract ( 599 )   PDF (635KB) ( 684 )  

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This paper considers the robust H_∞ filtering problem for linear uncertain Discrete Markovian jump system with time-varying delays and system parameters for norm of bounded uncertainty.Based on the Lyapunov functional theory and the introduction of additional matrix,new criteria are derived for the H performance analysis of the filtering-error systems,which lead to much less conservative analysis results.Then based on the obtained conditions,the gain of filter is obtained in terms of linear matrix inequalities (LMIs).Finally,numerical results are provided to show the effectiveness of the designed H filter.

Multi-channel FCM Signal Sorting Algorithms

DENG Huming,HU Min,HUANG Bo

. 2014, 27(9):  21. 

Abstract ( 669 )   PDF (878KB) ( 585 )  

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New radar systems poses new requirements on the radar signal sorting processing,which cannot be met by the algorithm based on statistics of histogram used nowadays.In this paper,FCM algorithm is studied based on a theoretical analysis in muti-channel background.A new radar signal sorting method is proposed.Simulation experiments demonstrate the feasibility of the algorithm.

An Improved Human Behavior Detection and Tracking Algorithm

HAN Junhao,ZHAO Huaixun

. 2014, 27(9):  25. 

Abstract ( 747 )   PDF (622KB) ( 661 )  

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In view the deficiency of the traditional human behavior detection algorithm in integrity and calculated amount,the interframe difference method is combined with background reduction division to detect the moving human target.And a tracking method of Kalman based on adjacent frames area match and grayscale match is proposed to improve stability and veracity of target tracking algorithm.Simulation experiments show that this method has better integrity and accuracy rate in the human action detection and tracking.

A Task Scheduling Algorithm for Parallel System Based on DAG

CHEN Maoqiang

. 2014, 27(9):  29. 

Abstract ( 628 )   PDF (685KB) ( 592 )  

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The task scheduling algorithms based on DAG are researched extensively.An improved algorithm suit for homogeneous bus-based parallel system is designed,which optimizes the rough computing method of the nodes' level by the traditional method and improves the scheduling of communication.Statistical scheduling experiments show the improvement of this algorithm over the traditional scheduling algorithms.

Coal Sales Recommendation Based on Bayesian Probabilistic

BO Lijun,XIA Wenjie,YAN Xinqing

. 2014, 27(9):  33. 

Abstract ( 645 )   PDF (639KB) ( 591 )  

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At present,the sale relation in large coal enterprise forms a star-like network,in which the sale and transportation company plays a center role,connecting multiple mines and customers and maintaining the alliance between the coal enterprise and customers.In coal trading,mines and customers examine the coal quality through random sampling to determine the transaction price.But the random sampling affects their identification of the coal quality,and may lead the disputation on coal quality.In this study,through mining the long-term accumulated transaction data between mines and customers,a Bayesian probabilistic method is proposed to calculate the credibility of the mines and the customers,the relative adaption degree on coal quality between the two dealers of transaction,and to recommend the suitable dealer for a possible transaction,thus significantly reducing the coal quality disputation and ensuring the profit for both parties.

Mean Shift Object Tracking Algorithm Based on Kalman Filtering

LIU Ke,WEI Naxin,LIU Fei

. 2014, 27(9):  37. 

Abstract ( 830 )   PDF (759KB) ( 651 )  

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Mean shift object tracking algorithm based on Kalman filtering is designed to solve the object occlusion problem in the object tracking field.The target location is obtained by mean shift algorithm for the selected targets,and by Kalman filtering forecasting according to the location and speed of the previous time for the blocked targets.Experimental results show that designed algorithm is more accuracy and practical when the target is blocked.

An Improved Probability W-SVM Algorithm Based on Density Estimates

CAO Huaxiao,WANG Cheng,SHAO Xiujuan,GONG Ling

. 2014, 27(9):  40. 

Abstract ( 743 )   PDF (666KB) ( 581 )  

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The probability density estimation algorithm based on W-SVM is studied.The existing algorithms only consider either the sampling time or the sample density,resulting in lager error probability density results.An improved W-SVM algorithm is proposed to improve the estimation precision by considering both the sample point of time and the use of area.Different types of penalty weighting coefficients are selected and normalized,and the most appropriate weighting factor is found by the grid optimization method.The simulation results show that the mean square error by the proposed improved probability weighted support vector density estimation is much smaller than that by traditional algorithms.

Development of Multiplayer Online 3D Virtual Robot Education System

ZHU Yuanlong,WANG Yixuan,WANG Yigang

. 2014, 27(9):  44. 

Abstract ( 800 )   PDF (1038KB) ( 568 )  

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Traditional robot education relies on costly physical robot and it is difficult in upgrading.The virtual robot education system is invented to reduce the cost of robot education.In this paper a new virtual robot education system developed by C+[KG-1.8mm]+ is presented with Ogre as the system graphics rendering engine.By adding the physics engine of NVIDIA PhysX,users can simulation the robot's movement in the real world.The information of robot's movement is transferred between clients by the TCP/IP protocol to realize the multiplayer online function.

Design and Implementation of Image Fusion IP Soft Core Based on FPGA and Matlab

TIAN Zijing,NA Yan,ZHANG Shoujiang

. 2014, 27(9):  48. 

Abstract ( 793 )   PDF (813KB) ( 648 )  

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This paper designs and implements a multi-focus image fusion algorithm converged IP soft core.The image fusion IP soft core is described in Verilog language under ISE environment,followed by testing and evaluation.Finally,the integration of data and the results are compared with the Matlab results to verify the accuracy of the designed IP soft core.

Design and Implementation of Assembly Language to C Language Translation Software

ZHAO Weikai,MENG Yang

. 2014, 27(9):  51. 

Abstract ( 667 )   PDF (550KB) ( 686 )  

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In view of the human power wasting and extended project cycle due to a be manual translation of large number of assembly codes in disassembly,the article develops an automatic tool for Assembly language to C language translation using the data structure tree types and sub-blocks method.The software can avoid problems caused by human translation and improve the efficiency of translation.

Correction of Image Output from Image Sensor MT9M034

GUO Shaochen,CHEN Wenyi

. 2014, 27(9):  54. 

Abstract ( 943 )   PDF (1499KB) ( 673 )  

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This paper discusses the error introduced by real-time high dynamic range image sensor MT9M034 during data compression while outputting images.The influence of the error on the algorithm based on CLAHE tone mapping is analyzed with the error correction method and FPGA implementation circuit given.The result shows that error correction method not only reduces the error,but also improves the CLAHE tone mapping.

Research on Embedded Eye Tracking System Based on OpenCV

HU Yufeng

. 2014, 27(9):  58. 

Abstract ( 791 )   PDF (746KB) ( 799 )  

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For the visual control system,it is very important to locate and track eyes position and judge the state of eyes.A detection method for human eye identification and tracking of the video image based on OpenCV is proposed in this paper.This method combines camera equipment and OpenCV correlation function and designs a system to achieve the goal of eye detection and tracking on the embedded platform.The experimental results show this method meets requirements of human eye recognition with high recognition speed and accuracy,and is of practical value.

Realization of Sobel Edge Detection Based on FPGA in Real-time Video Signal

JIAO Shuhong,GUAN Chenhui

. 2014, 27(9):  62. 

Abstract ( 782 )   PDF (682KB) ( 619 )  

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In real-time video signal processing,due to the large amount of data in image processing such as image edge detection,the system uses the FPGA+DSP image processing program.With parallel processing of the data,FPGA is used to realize lower processing algorithms that process the amount of data with high processing speed and simple algorithm structure.The paper describes a method for Sobel edge detection based on FPGA,and proposes an adaptive threshold processing method.Experimental results show that FPGA is able to complete Sobel edge detection of real-time video signals.Adaptive threshold module ensures the good effect of image edge detection of the system in case of changing ambient brightness.

ANN Based on Matlab and its Application in the Ultrasonic Liquid Level Measurement

LIU Chun

. 2014, 27(9):  65. 

Abstract ( 757 )   PDF (521KB) ( 621 )  

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In this paper,ANN program is developed by calling Matlab toolbox function in order to identify the liquid level.Thirty signals on the surface and thirty signals below the surface are trained.The trained network can distinguish the type of the signal well,which shows that the sorting method based on ANN works well in the ultrasonic liquid level measurement.

Development of Fire Detection System Based on Power over Ethernet

CHEN Changzheng,YIN Kun,GONG Wanwan,LIU Shixing

. 2014, 27(9):  71. 

Abstract ( 729 )   PDF (802KB) ( 691 )  

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A fire detection system based on PoE (Power over Ethernet) technology is introduced.Real-time analog fire parameters are collected by adopting the proposed new technology.With the application of TCP/IP technology,the data are transferred to the server for further processing via RJ-45 network interface,which makes it easy to reproduce fire virtual scene and forecast fire trend.The system reduces the distorted fire rate and makes fire monitoring reliable.An energy supply is also provided to fire detection node through the Ethernet port,which simplifies the hardware structure of the system and facilitates the circuit board layout.

CMS Monitoring System Software Based on Java Applet

ZHENG Yong,WANG Jun

. 2014, 27(9):  75. 

Abstract ( 778 )   PDF (576KB) ( 546 )  

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This paper develops a CMS monitoring system based on the java language and Eclipse IDE.Users can download and run the applet software from CMS devices via browser,and communicate with the application on CMS to send the command and obtain the message for remote monitoring and control.It is shown that the program realizes desired functions.

Design of Multi-area Video Monitoring System Based on IP Network Cameras

WANG Peiguo,YANG Yanfang

. 2014, 27(9):  78. 

Abstract ( 741 )   PDF (817KB) ( 750 )  

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A video surveillance networking system based on a set of IPC is proposed for multi-area network video monitoring.This system applies some key techniques,such as moving objects detection by video analysis,dual video stream transferring and storing technique,and the priority multi-channel interaction technique between IPCs and the image server.It is capable of monitoring multiple areas by supplying a full-time video record with standard resolution,meanwhile capturing continuously images in high resolution when any moving objects are detected.The proposed system is compatible with the existed systems,and has a high cost performance.

Design of Fall Detection System for the Old on Android Platform

SHI Ting,HE Zhinan,JIANG Ning,WANG Xiumei

. 2014, 27(9):  82. 

Abstract ( 773 )   PDF (878KB) ( 704 )  

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This paper presents an Android mobile application to detect the fall of the old based on sensors,wireless communication and locating technologies.A message is sent to the family members when a fall is detected,which contains the location of the old,the name and the phone number of nearby capitals.This system can improve the quality of health care by providing timely help to the old.

The Design of Repair Application System Based on Web

SUN Ning,YAN Zi'an,WANG Chi

. 2014, 27(9):  85. 

Abstract ( 889 )   PDF (1084KB) ( 608 )  

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In view of the huge resident population in south campus,traditional way of artificial service can not satisfy the requirement of rapid and accurate processing.For the convenience of the user's information feedback,alleviate the pressure of the huge security,scientific and effective arrangement of personnel work,improve efficiency,need to develope the Repair application system based on Web.Through the ThinkPHP framework,The paper describe the development of the Repair application system,which was based on WAMP Environment,and expond the key technologies,system structure and the database design.Now the system has been launched into practical operation,improve the infrastructure sector repair efficiency.

Research on Mobile Smart Campus

MAO Zhigang,XU Xiaoliang

. 2014, 27(9):  89. 

Abstract ( 881 )   PDF (1007KB) ( 640 )  

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A mobile Internet-based smart campus platform is proposed to solve the problems of traditional digital campus systems,such as low utilization of resource,lack of personalized information services.The portable platform based on a network of campus information and mobile communication technology supports access to the information anytime and anywhere.With the mobile push technology,the platform offers different push models under different scheduling requests and provides personalized information services.The applications show that the proposed mobile intelligence platform supplies an effective intelligent management and comprehensive services for the schools.

Research on Performance of Portable Ultra-wideband Through Wall Imaging Radar under Different Array Modes

HU Xikun,ZHU Guofu,JIN Tian

. 2014, 27(9):  93. 

Abstract ( 860 )   PDF (1203KB) ( 640 )  

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Considering the requirement of portability,the number of antennas used for the portable ultra-wideband (UWB) through wall imaging radar (TWIR) is limited.It is faced with challenges to take full advantage of antennas to obtain the optimal performance.In this paper,we study three kinds of array configuration modes and compare their imaging performance based on two criterions-cross-range resolution and interference region (IR).Our simulation results show that the array configuration should be considered carefully to get the optimized aperture and element density.

Research on Information Fusion Technology for Active-Passive Radar Composite Seeker

YOU Xiaowei

. 2014, 27(9):  97. 

Abstract ( 677 )   PDF (906KB) ( 425 )  

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In the present work,an information fusion algorithm based on sequential extended Kalman filtering (SEKF) for the active-passive radar composite seeker is proposed.First,the angle error is achieved from the active-passive radar composite seeker,and then an optimization strategy is used to weight the matched angle errors,which can be used to estimate the dynamic information of the targets.The experiments show that the steady-state error of state estimation based on active-passive radar information fusion is smaller than that relies on active radar measurement only.Meanwhile,the former filter has a faster convergence.

Evaluation of Radar Net Anti-Jamming Capacity Based on SVM

YUAN Chaopeng,LI jiang

. 2014, 27(9):  101. 

Abstract ( 825 )   PDF (541KB) ( 440 )  

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The assessment of the anti-jamming capability of radar network in operation is realized by taking the evaluation indexes of radar network and their corresponding values as samples,which are evaluated using the forecasting ability of SVM.The results are compared with those based on fuzzy matter-element of information entropy,which shows that the proposed assessment has the characteristics of fast computing,good generalization ability and accurate assessment results.

Design of an Accurate Linear Temperature Compensation

YANG Chan,ZHANG Qinyang,GUAN Yaobin,HE Jun

. 2014, 27(9):  104. 

Abstract ( 716 )   PDF (559KB) ( 609 )  

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The majority of power is consumed by the power tube in the linear charging circuit,leading to rising chip temperature.This paper proposes a linear temperature compensation circuit,with which the charging current gradually reduced with rising temperature to prevent further increase in temperature of the chip.Precise control is realized by the design,making small changes with the craft corner,with simulation results of ±5 ℃.

Implementation of Non-linear Frequency Modulation Signals Pulse Compression Based on FPGA

XU Fei,CHEN Jianchun,LI Yingxin

. 2014, 27(9):  106. 

Abstract ( 860 )   PDF (641KB) ( 537 )  

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Non-linear Frequency Modulation Signals in the signal design that takes into account distance sidelobe suppression of pulse compression signals,weighted networks without adding hardware implementations to suppression distance sidelobe.The design of non-linear frequency modulation signals is introduced,and the pulse compression signal performance of different design methods for non-linear frequency modulation signals is simulated.A bandwidth of 30 MHz at a sampling rate of 100 MHz is achieved with 16 bit input signal quantization,10.24 μs length of the linear and nonlinear frequency modulation signal compression in the FGPA simulation environment.

Design of an Error Amplifier for Improving Transient Response of DC-DC Converter

XU Chongwei,YANG Ling,HAN Zhichao,LIU Yuezhi

. 2014, 27(9):  109. 

Abstract ( 797 )   PDF (691KB) ( 524 )  

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A novel error amplifier is presented to improve the transient response of DC-DC converter.The output impedance and compensation resistors of the error amplifier are dynamically adjusted according to different load conditions for the system to achieve enough phase margins.A current sensing circuit and a logic choice circuit are designed to derive load change and choose the switch to turn on.The test results show that the DC-DC converter with the proposed structure reduces the overshoot by 50%.

Microstrip Antenna Miniaturization Using Defected Ground Structure

LU Hanyang,DAI Wei,ZHU Weimin

. 2014, 27(9):  112. 

Abstract ( 863 )   PDF (569KB) ( 1047 )  

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An effective microstrip antenna miniaturization method is proposed for microstrip antenna array using defected ground structure etched on the ground of the microstrip antenna.The relationship between the performance of the antenna and the size of the DGS is studied.HFSS simulation shows that the size of the antenna with DGS is more than 30% smaller than that without it,and the performance of the antenna with DGS indicates that the DGS is effective in antenna miniaturization.

Design of Minitype Tri-band Microstrip Antenna for WLAN/WiMAX Applications

MA Shiwei,QIAO Long,DING Xu

. 2014, 27(9):  115. 

Abstract ( 839 )   PDF (569KB) ( 680 )  

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A minitype tri-band microstrip antenna is designed in the local area network for 2.4 GHz and world interoperability for microwave access for 3.5 GHz/1.8 GHz wireless telecommunications applications.The structure of antenna mainly is a similar T-slot loaded on the circle patch.The proposed antenna has the advantages of small size,simple structure,easy fabrication,low cost and omnidirectional irradition.An electromagnetic model of the designed antenna is developed in HFSS for numerical analysis and optimization.The results show that there is a satisfactory agreement between measured data and simulated data.The antenna with Return Loss is less than -10 dB at three frequency points and has a good orientation.It has good impedance matching characteristics in the support band with VSWR less than 2,proving the rationality of the design of microstrip antenna.

Application of Moving Average in Data Sample and Analysis

GUO Yongdong

. 2014, 27(9):  118. 

Abstract ( 643 )   PDF (771KB) ( 683 )  

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In quench detection,noise signals originated from the spike effects in the power supply give rise to the quench malfunction action and affect the normal operation of the superconducting magnet.In this paper,the sample data in multiple quench detection channels are smoothed by the moving average method to lower the quench detection threshold,thus reducing the quench malfunction times.The moving average method can be widely used in a dynamic data sampling and data analysis.

Design of a Circuit in Boost DC-DC for Fast Transient Response

LIU Yuezhi,HUANG Yue'e

. 2014, 27(9):  121. 

Abstract ( 752 )   PDF (600KB) ( 624 )  

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A circuit is designed to improve the transient response of the boost DC-DC converters.The output voltage of the DC-DC converter is sensed to adjust the transconductance and compensation resistors in the error amplifier and to improve the loop bandwidth,thus enhancing the system's transient response.The circuit is implemented in a synchronous boost DC-DC converter with input voltage as low as 1.4 V and with output voltage 2.5~6.5 V.Based on 0.25 μm CMOS technology,the chip simulation results demonstrate the settling time of the chip is decreased by 45% and the overshoot and undershoot voltage is cut down by 35% under 200 mA to 2 A load transient condition compared with the traditional synchronous boost DC-DC converter.

Modulation Recognition of PSK Signal in Wavelet Package Domain

CHEN Jie

. 2014, 27(9):  124. 

Abstract ( 792 )   PDF (578KB) ( 830 )  

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In this study,automatic modulation recognition (AMR) of digitally phase shift keying signals,including BPSK,QPSK and 8PSK,by using continuous wavelet package transform (CWPT),is presented.Firstly,according to the characteristic of each modulated signal,three templates of target signals are set,decomposed into wavelet package domain (WPD) to form sub-domain templates,and then stored in advance.While AMR is implemented,the real signal is decomposed into wavelet package domain (WPD) and then cross correlated with the sub-domain templates.On the basis of the results of cross correlation,the modulation is identified.For the finer frequency division of WPD,the recognition rate is better than that by the general wavelet decomposition recognition.The signals are generated with Monte Carlo method.And the presented new method is simulated with Matlab.The outcomes of simulation show that the new method has a higher recognition rate,and particularly at low signal noise rate the method can precisely recognize the psk type of target signal.

Design of Micro-mechanical Capacitive Acceleration Sensor with Biax

SHEN Wenqing,HU Fangfei

. 2014, 27(9):  128. 

Abstract ( 625 )   PDF (1026KB) ( 434 )  

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This paper design a micro-mechanical biaxial capacitive acceleration sensor with high sensitivity and low mechanical noise.Both X and Yaxial of the sensor have two groups of testing unit with symmetrical structure,which effectively solves the problem of Cross coupling between the axial direction and measurement error,and the structure of limiting device avoids the failure of structure due to large acceleration value.The size of sensor quality is 3 250 μm×3 250 μm×5 μm,and the size of grid structure is 1 575 μm×35 μm×5 μm.Simulation of the performance of acceleration sensor by the ANSYS shows that both X and Y axial static sensitivity of acceleration sensor is 0.253 μm/g;both X and Yaxial capacitance sensitivity of acceleration sensor is 1.533 pF/g;and both X and Yaxial resonant frequency is 949 Hz with a damping ratio of 0.83.The simulation results verify the feasibility of the design.

Processing Method of the Output Signal of JC Torque and Rotary Speed Sensor

ZHANG Jiao,JIN Peng

. 2014, 27(9):  132. 

Abstract ( 688 )   PDF (1162KB) ( 668 )  

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A reasonable signal processing method for the conversion between electrical signal and torque speed signal is proposed according to the working principle of JC sensor to obtain more accurate torque and speed signal.In this experiment,PIC18F458 microcontroller is used to magnify,filter,and shape two sinusoidal electrical output signals of the JC sensor to gain two same frequency square waves,and RS flip-flop to convert the phase difference of the two sinusoidal signal into the pulse width the flip-flop's output.The pulse count method is adopted to measure the square wave signal's frequency to obtain speed,the equal precision measuring method to detect the output pulse width of the RS flip-flop to obtain torque,and the moving average is also used to improve accuracy and stability of the signal.The experimental results show that the proposed method can effectively measure the torque and rotary speed,and has practical value on the application in electric vehicles and mechanical power plant instrumentation.

Engraving Machine NC Control System Based on Embedded SoC Microcontroller

WANG Suohong

. 2014, 27(9):  137. 

Abstract ( 561 )   PDF (612KB) ( 601 )  

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In view of the wide application of the engraving machine,an embedded SOC microcontroller controlled engraving machine is developed.It is of less production costs than the engraving machines based on PC or DSP.The control system block diagram with the C8051F120 microcontroller as core processor is presented.The basic theory of the line interpolation using point-by-point comparison method is discussed.The system software function is also introduced.Practical tests show that the carving accuracy is 0.01 mm.With fast carving speed,the design is of economic value.

DC Current Detecting and Application of Medium Power Inductive Load

YANG Chang,CAO Changmao,SUN Cheng,PENG Jian,CAI Xuebei,ZHENG Guo

. 2014, 27(9):  140. 

Abstract ( 761 )   PDF (588KB) ( 485 )  

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To find a simple and efficient way to detect the DC current of the medium power inductive load circuit,several feasible scheme are discussed in this article.The best one,standing up to comparison and verification,was selected out.And enumerate instance to illustrate its application field and the implementation mode.The projects mentioned in this article adopt the MAX9918 chip from Maxim,a single-power-supply,high-precision and current-sensitive amplifier.This kind of chip features relatively high ICMR(input common-mode range),which can be extended to as wide as -20 to +75 V.This amplifier is much applicable to monitor inductive load current detection,such as,DC motor and solenoid.

Analysis Chaotic Behavior and Its Control in DC-DC Buck Converter

WANG Yan,LI Jie

. 2014, 27(9):  143. 

Abstract ( 714 )   PDF (770KB) ( 428 )  

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The chaos control in the DC-DC circuit has great application value in the practical engineering.The generating mechanism of chaos and the advantages and disadvantages of its control method are studied,the mechanism of the chaos in the DC-DC buck converter from the energy transfer view is analyzed,and the main reason for generating chaos pointed out that the energy of the system is increasing.Based on the above analysis,the method of current of inductor is used to construct the feedback controller to control the chaos in the DC-DC Buck converter.Theoretical analysis,numerical calculation and circuit simulation demonstrate the effectiveness and validity of this chaos control.

Analysis of PLL Based on FPGA in Distorted Three-phase Grid

LIU Chao,ZHUANG Shengxian,LIU Sijia,XIE Maojun

. 2014, 27(9):  148. 

Abstract ( 846 )   PDF (1034KB) ( 429 )  

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For the three-phase PV grid inverters to accurately and quickly lock the fundamental phase in a variety of grid environments,a digital PLL design based on the basic structure of a three-phase locked loop in FPGA is presented.Dq transformation,PI controller,NCO module and other test modules are programmed in assembly line Verilog HDL.And FPGA is used to verify the system,the PLL output errors under distorted three-phase grid are analyzed such as the phase unbalancing,frequency-abrupt,and phase-abrupt and harmonics.Finally,the distorted grid is maltab simulated and the system modelsim simulated.The simulation results prove that the three-phase PLL can lock the grid fundamental phase fast and accurately in fault situation.

Design of Timing Output Power Control Device Software

HUANG Guimei,WANG Xia,LIU Yongli,SHAO Lianhe

. 2014, 27(9):  153. 

Abstract ( 557 )   PDF (828KB) ( 400 )  

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A multi-period timing adjustable output power control device is designed with Mega16 chip as the core,the clock chip 1307 as the base,and the high-pressure optocoupler driving high-power silicon controlled rectifier device for the implementation.The working process of the timing output power control device is described,the timing output power control device hardware principle and characteristics are analyzed,and the timing output power software of control device is interpreted.The device is used for the power control of large power equipment timing running.Practice uses prove that the device can reduce the workload,conserve energy and lower carbon emission.

A Research on Analog Signal Data Acquisition for Merging Unit in 35 kV Digital Substation

PENG Dizhuo,XU Xuejun,TANG Qin,LI Ji

. 2014, 27(9):  156. 

Abstract ( 712 )   PDF (822KB) ( 400 )  

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An analog signal acquisition card is designed for the output signal of 35kV substation.The acquisition circuits for small analog signal from the electronic transformer and analog signal from the traditional transformer are designed respectively to receive multi-channel analog signals simultaneously.Experiments verify the correctness of its functions,and show that the card fully meets the design requirements of precision data acquisition of the merging unit.

Research on Microgrid Mode Switch and Control and Device Development Based on VLD

AI Shuyun,WU Bingxin,XIE Weihua,LI Xianwei

. 2014, 27(9):  160. 

Abstract ( 662 )   PDF (1326KB) ( 443 )  

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Different from large grids,a micro-grid has two operating modes:grid-connected operation and islanding operation mode (also known as off-grid operation).For the fast switching between grid-connected operation and islanding operation,this paper analyzes the architecture of the micro-grid and grid-connected mode switching,develops the micro-grid mode switch device,and completes the modular design based on the introduction XJ visual simulation software (VLD).This design effectively reduces the slow mode control switching to within 120 ms,thus "seamless" grid-connected and off-grid switching,which has wide application in engineering.

Specific Harmonic Improvement of a Single-phase Three-level PWM Rectifier

ZHONG Zhilei,LI Qianyong

. 2014, 27(9):  165. 

Abstract ( 923 )   PDF (676KB) ( 394 )  

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The power device in three-level rectifier has small voltage stress,less input current harmonic,and better sine degree.The various work condition of combined switch and the working principle of the rectifier are analyzed.The transient direct current control is selected as the current inner control method for the simulation of the system.In addition,the causes of the three times current harmonic on the net side of the single-phase PWM rectifier is analyzed.And a new type of harmonic suppression method is adopted to restrain the current harmonic.Simulation shows the effectiveness of the new control algorithm in restraining the three times current harmonic,and the total harmonic distortion rate is reduced as well.

High-Precision Constant Output Current Control for Primary-side Regulated AC/DC

HAN Zhichao,HE Jun,WANG Rong,XU Chongwei

. 2014, 27(9):  169. 

Abstract ( 650 )   PDF (516KB) ( 388 )  

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A high-precision control strategy for the primary-side regulated AC/DC is proposed to deal with the low precision of constant current owing to the inaccurate peak current detection by the conventional primary-side regulated AC/DC.The control strategy estimates the real primary peak current by use of the slope detection of I_pk to improve constant output current precision.Experimental measurements of the LED driver circuits are presented to verify the performance of the proposed control strategy.The strategy improves constant output current precision and can achieve about 2% output current tolerance for 85~265 V input voltage range.

Freeform Surface Lens Design for LED Uniform Illumination

ZHANG Chengliang

. 2014, 27(9):  172. 

Abstract ( 784 )   PDF (845KB) ( 883 )  

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This paper comes up with a method of lens design to realize the LED uniform illumination,since the emission characteristics of the most LED behave as Lambertian source.The proposed method builds an equation of a freeform surface lens which can produce uniform spots,and obtains a numerical solution by using Matlab.Then a lens is modeled through modeling software Pro/E,and verified by Tracepro.The results of lighting simulation and analysis show that the proposed method produces good uniform spots.

Study of Low-temperature Si/Si Bonding with Polymer Medium

GUAN Peng,ZHAN Minghao

. 2014, 27(9):  175. 

Abstract ( 805 )   PDF (609KB) ( 570 )  

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Low-temperature bonding using polymer medium is a key technique of the wafer-level adhesive bonding in MEMS devices.With BCB,Parylene,Polyimide,PMMA as the bonding medium,the bonding temperature,bonding force,atmosphere and bond strength are studied,and their advantages and disadvantages are analyzed.Parylene bonding parameters are optimized by changing spin coating,bonding temperature,bonding force,bonding times and etc.The results show that low temperature bonding encapsulation of MEMS devices has good bonding strength (>3.600 MPa) at 230 ℃,meeting the requirements of the wafer-level adhesive bonding in MEMS devices.

Object Detection System Design Based on the Photoelectric Sensing Technology

GU Shuai,WANG Yuye

. 2014, 27(9):  178. 

Abstract ( 776 )   PDF (535KB) ( 663 )  

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An object detection system based on optical sensing technology is designed using infrared light-emitting diodes and infrared phototransistor in the sensing circuit.The microcontroller NUC130LE3CN is responsible for light emission intensity level control and the receiver detection,with luminous intensity controlled by the microcontroller IO port output PWM waveform.The adjustable luminous intensity offers high detection sensitivity in different ambient light intensities and error alert function.