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15 March 2019 Volume 32 Issue 3
  
    An Extraction Scheme of Target Edge Based on Triangular Patches
    LI Tong,LI Han
    Electronic Science and Technology. 2019, 32(3):  1-5.  doi:10.16180/j.cnki.issn1007-7820.2019.03.001
    Abstract ( 449 )   HTML ( 22 )   PDF (840KB) ( 121 )  
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    As one of the powerful tools to calculate the electromagnetic scattering effects of electrically large objects, the equivalent edge current method is widely used. The edge extraction plays an important role in the analysis of complex target. Based on the characteristics of the target model, a method for edge data extraction was proposed in this paper. The target was modeled and its triangular patches data was outputted by Hypermesh, then the exhaustive method was used to find all triangular patches and their adjacent patches data. The triangle data belonging to the target edge was obtained by setting the angle threshold. The convexity and concavity of the edges contained in target were determined by solving sum vector. The numerical results showed that the proposed method could extract edge data accurately and reliably.

    Modeling Identification for High Order Process with Time-delay in the Frequency Domain
    SHAN Yongming,WANG Yagang,WANG Kai
    Electronic Science and Technology. 2019, 32(3):  6-9.  doi:10.16180/j.cnki.issn1007-7820.2019.03.002
    Abstract ( 343 )   HTML ( 4 )   PDF (532KB) ( 127 )  
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    For the high order process with time-delay in industrial control systems, the second-order plus pure lag model was used to identify the frequency domain because it was difficult to design the controller. By sampling the input and output data of the object, the frequency response was analyzed and the important frequency segments were determined. Several important frequency response points were selected, and the system model parameters were estimated by the amplitude-frequency characteristics to achieve model reduction. The simulation results of MATLAB showed that the proposed method was suitable for a wide range of high-order time-delay objects and had good accuracy and robustness.

    Study on the Fault Diagnosis of Check Valve Based on KPCA-LSSVM
    MU Zhuqing
    Electronic Science and Technology. 2019, 32(3):  10-15.  doi:10.16180/j.cnki.issn1007-7820.2019.03.003
    Abstract ( 409 )   HTML ( 4 )   PDF (827KB) ( 48 )  
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    It was difficult to extract and diagnose the characteristic of the fault vibration signal of the check valve of the high pressure diaphragm pump. To solve the problem, KPCA combined with LSSVM were performed for fault diagnosis research. The bi-stable SR method and DEMD algorithm were used to preprocess the signal of each state of the one-way valve, and the principal component of the decomposed K-L divergence was used to extract feature parameters of the time-frequency domain to construct the feature vector set. The second feature extraction of vector set was carried out by KPCA, which were further input into the LSSVM diagnostic system to complete check value fault diagnosis and classification. The experimental data proved that the fault diagnosis rate of this method was 90%, and the fault feature of the one-way valve could be diagnosed well.

    Simulation of Turbine Governing System Model for Various Diversion Systems
    XIAO Yu,CHEN Tie,KE Haoyun,WANG Peng
    Electronic Science and Technology. 2019, 32(3):  15-20.  doi:10.16180/j.cnki.issn1007-7820.2019.03.004
    Abstract ( 438 )   HTML ( 9 )   PDF (887KB) ( 74 )  
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    As one vital component of a hydropower station, the normal operation of the turbine governing system is directly related to the security and stability of the hydro generator unit. Due to the complex and diverse structure of the diversion system, different types of diversion systems have different effects on the hydraulic turbine governing system. In this paper, the changes of relevant parameters of the hydraulic turbine governing system were analyzed by setting different water hammer conditions in the hydraulic system model of individual penstock. Then, the parameter waveforms of the hydraulic system model of individual penstock and the hydraulic system model of surge-penstock were compared under the simulation test of no-load and small-load disturbance. The simulation results showed that the relevant parameters were different at the initial stage of the system change operation because of the difference in the structure type of the diversion system, but it could stabilize in the end.

    Design of Double Closed-loop Speed Regulating System for Permanent Magnet Synchronous Motor
    HU Jianqiu,DING Xueming
    Electronic Science and Technology. 2019, 32(3):  21-25.  doi:10.16180/j.cnki.issn1007-7820.2019.03.005
    Abstract ( 1806 )   HTML ( 48 )   PDF (679KB) ( 235 )  
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    Permanent magnet synchronous motor has been widely used for its excellent performance. Aiming at the problem of unsatisfactory control results caused by the difficulty in parameter setting of dual closed-loop controllers, an improved double closed-loop PI controller based on pole configuration and Ramp function was proposed. From the perspective of the vector control algorithm of the permanent magnet synchronous motor, the system model of decoupling control with double closed-loop speed and current was established. In this model, the design methods of speed loop and current loop controller were discussed, and the calculation results of the parameters of the improved double loop controller were given. Computer simulations and practical tests were conducted on the research methods. The results showed that the optimized system reduced system overshoot, shortened the settling time, improved the dynamic response of the system, which indicated good engineering significance.

    Economic Operation of Microgrid Considering Operational Risk and Customer Satisfaction
    ZHANG Jinwei,LI Guoping
    Electronic Science and Technology. 2019, 32(3):  26-31.  doi:10.16180/j.cnki.issn1007-7820.2019.03.006
    Abstract ( 439 )   HTML ( 6 )   PDF (621KB) ( 133 )  
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    Solving the randomness and volatility of the new energy output in the microgrid is the premise and key to the optimal operation of the microgrid. In this paper, the robust optimization theory was introduced into the operation optimization of microgrid, and the multi-objective robust optimization model of microgrid with wind power generation, micro gas turbine, distribution network and battery was constructed with the aim of running cost and environmental cost. The natural selection particle swarm optimization algorithm was performed to solve the proposed model. The simulation results showed that compared with the traditional deterministic optimization, the robust optimization sacrificed the economical, but the reliability of the microgrid operation was balanced, and the relationship between cost and risk was balanced. At the same time, multi-objective optimization balanced the economic and environmental protection of the microgrid, providing a reference for the optimal operation of the microgrid.

    Cost Optimization Model for Cloud Resource Allocation Based on Packet Cluster
    LÜ Tengfei,CHEN Shiping,WANG Lei
    Electronic Science and Technology. 2019, 32(3):  31-36.  doi:10.16180/j.cnki.issn1007-7820.2019.03.007
    Abstract ( 391 )   HTML ( 5 )   PDF (584KB) ( 35 )  
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    To resolve the high cost in cloud computing data center caused by traditional resource management, a cost optimization model for cloud resource allocation based on packet-cluster was proposed. The model abstracted the specific needs of the users into individual requirements packages and integrated various resources of data center into resource clusters. Through the improved particle swarm algorithm based on the concept of package clustering, the deployment mapping of demand packages to resource clusters were finally implemented. The experimental results showed that the model was not only effective to reduce operating costs in resource allocation process but also improved the resource utilization of physical servers.

    Cross-correlation Based Real-time Pulverized Coal Flow Monitoring System
    ZHU Zhengfei,WEI Zhangyuehao,YUAN Xudong
    Electronic Science and Technology. 2019, 32(3):  36-41.  doi:10.16180/j.cnki.issn1007-7820.2019.03.008
    Abstract ( 787 )   HTML ( 5 )   PDF (1169KB) ( 87 )  
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    The flow rate of pulverized coal in the pulverized coal injection process of industrial blast furnaces is difficult to monitor, and the problem of uneven input and clogging of boiler pulverized coal is likely to occur. In order to monitor the accurate flow rate in the transportation pipeline in real time, this paper proposed a high-precision coal flow monitoring system based on cross-correlation and capacitance detection. The system mainly contained two parts: weak capacitance detection circuit and capacitance sensor. Two-layer shielded capacitive sensors were designed based on field test results, and a high-precision, low-noise digital-analog hybrid capacitance detection circuit was built. Filtered the interference signal while preserving the characteristic fluctuations required by the cross-correlation algorithm using a filtering algorithm that preserved the cross-correlation feature. Combining the current velocity given by cross-correlation algorithm and concentration converted from capacitance detection system’s output, multi-pipe accurate flow rate could be obtained finally with CAN bus. The experimental results showed that the error in the practical application of the system could be controlled at about 5%, indicating the method had higher accuracy and met the needs of complex engineering environments.

    Fault Diagnosis Method of Transmission Network Based on Rule Reasoning
    YANG Siqi,CHEN Wei,ZHANG Qingqing,XIE Ye
    Electronic Science and Technology. 2019, 32(3):  42-46.  doi:10.16180/j.cnki.issn1007-7820.2019.03.009
    Abstract ( 404 )   HTML ( 3 )   PDF (736KB) ( 50 )  
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    If there was a fault in the transmission network with no safety measure, it might produce unpredictable losses and consequences, so fault diagnosis of the power grid had become an important research object. The alarm information generated by the fault was complicated, which increased the difficulty of staff fault diagnosis. Based on the above problems, a fault diagnosis method for transmission network based on rule reasoning was proposed by this paper. By establishing the Petri network model of the power network, the structural information of the diagnosable subnet of the fault transition was analyzed and the flow of tokens in the diagnosable subnet was described,then the fault element location was determined through the related fault rule reasoning, and the fault simulation calculation was carried out by using the local circuit diagram of IEEE-14. The results showed that the rule based on reasoning fault diagnosis method could accurately and quickly locate and analyze the fault of transmission network, and it was a reliable and effective fault diagnosis system.

    Analysis on Electric Field and Electrodynamics Force of Switching Air-core Reactor
    WANG Yang,LI Yingna,LI Chuan
    Electronic Science and Technology. 2019, 32(3):  47-52.  doi:10.16180/j.cnki.issn1007-7820.2019.03.010
    Abstract ( 291 )   HTML ( 2 )   PDF (1045KB) ( 26 )  
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    For the influence of frequent switching operations on the insulation of dry-type air-core reactors, in order to ensure the safe and stable operation of the power system, the simulation and experimental analysis methods were applied to analyze the electric field and electrodynamics force of the reactor under steady state and switching transient state. The distribution and numerical changes of electric and electrodynamics force were further compared under the two states through the establishment of simulation model of Maxwell’s air-core reactor. The results showed that the electric field strength and electrodynamics force under the switching operation were significantly increased compared with that under the steady state operation, and the insulation thickness needed to reach 0.0325mm to constrain the radial electrodynamics force generated during the switching process. The transient switching process imposed a higher requirement for the insulation thickness of the reactor, which provided a certain theoretical basis for the industrial design of the air-core reactor.

    An Improved LeNet Network
    HU Demin,CHENG Pufang
    Electronic Science and Technology. 2019, 32(3):  53-57.  doi:10.16180/j.cnki.issn1007-7820.2019.03.011
    Abstract ( 676 )   HTML ( 20 )   PDF (573KB) ( 112 )  
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    Aim

    ing at the problems of low learning efficiency, slow convergence and long training time in convolutional neural networks, this paper presented an improved LeNet convolutional neural network model. The model used a convolutional kernel whose convolution scale was set as 3 and stride was set as 2 instead of the original pooled layer, and added a batch normalization layer before each activation function layer. Experiments on the Mnist dataset showed that compared with the traditional LeNet network, the convolutional neural network proposed in this paper improved the accuracy rate and had faster convergence speed and shorter training time.

    Design of MEMS Capacitance Pressure Sensor Measurement Circuit Based on Pcap01
    BAO Binghao,CHEN Liang
    Electronic Science and Technology. 2019, 32(3):  57-60.  doi:10.16180/j.cnki.issn1007-7820.2019.03.012
    Abstract ( 732 )   HTML ( 21 )   PDF (758KB) ( 151 )  
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    Based on the principle of TDC, a weak capacitance measurement circuit for MEMS capacitive pressure sensors was proposed in this paper. Taking STM32F103 as the main controller, the circuit conducted the timing control of Pcap01 through SP1 bus to complete the collection, analysis, processing and display of the capacitance data. The circuit had the characteristics including small volume, strong anti-interference ability, high resolution and high update rate. Measurements of static capacitance below 10 pF and MEMS capacitive pressure sensor showed that the circuit had a good performance with resolution of 61 aF and 16 bits of effective precision at a refresh rate of 10 Hz.

    Cloud Computing Energy Consumption Optimization Algorithm Based on Package-Cluster Mapping
    LU Le,CHEN Shiping
    Electronic Science and Technology. 2019, 32(3):  61-66.  doi:10.16180/j.cnki.issn1007-7820.2019.03.013
    Abstract ( 348 )   HTML ( 9 )   PDF (774KB) ( 33 )  
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    Aim

    ing at the problem of flat layout and complex structure in the virtual machine placement strategy, this paper adopted a virtual machine allocation framework based on package-cluster mapping to minimize the energy consumption of all physical machines. Based on this, an effective energy consumption model and an improved binary particle swarm optimization algorithm with adaptive weights were proposed to improve the speed and accuracy of package-cluster mapping framework. Experimental results showed that the improved binary particle swarm optimization algorithm was more superior to traditional binary particle swarm optimization in terms of convergence speed and optimization ability. Compared with the virtual machine allocation algorithm, the improved binary particle swarm allocation algorithm based on the clustering framework increased the CPU usage and effectively reduced energy consumption, which promoted the green energy saving.

    A New Trapezoidal Control Method of Sensorless BLDCM
    WANG Xingfang,JIN Shiqun,XING Jinyu,HOU Shaoyang,WANG Zhe
    Electronic Science and Technology. 2019, 32(3):  67-71.  doi:10.16180/j.cnki.issn1007-7820.2019.03.014
    Abstract ( 690 )   HTML ( 5 )   PDF (694KB) ( 47 )  
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    Sensorless brushless DC motor is mainly controlled by the back-EMF method. However, a variety of disturbances in the control method will cause glitches and ripples in the waveform of Back-EMF,leading to erroneous judgment of the zero-crossing point of Back-EMF. In this paper, a sensorless BLDCM control method was proposed, and the proposed optimal function was used to filter the results of the Back-EMF detection. By analyzing the back EMF waveform, the optimal function was used to filter the glitches and ripples near zero-crossing point of the Back-EMF to avoid the misjudgement of the zero crossing point of the back EMF. Finally, the commutation time of the motor drive voltage was obtained, and the level of precise control of motor was improved. Experimental results proveed the correctness and feasibility of the new BLDCM sensorless trapezoidal control method.

    Research on the Partial Key Factors Affecting the Junction Temperature of High Power LED Lamp Chip
    XIAO Yuanbin,YANG Ping
    Electronic Science and Technology. 2019, 32(3):  72-76.  doi:10.16180/j.cnki.issn1007-7820.2019.03.015
    Abstract ( 540 )   HTML ( 4 )   PDF (847KB) ( 32 )  
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    Due to the problem of high junction temperature during the lighting of LED lamp chips,two key factors affecting the junction temperature: distance between the light sources in the LED lamp chip and the spacing between the chips were studied in order to effectively reduce the junction temperature of the chip. This paper used ANSYS Workbench16.0 software for chip thermal simulation and verified the reliability of simulation results by the constant temperature test platform. The simulation results showed that properly setting the spacing between the internal light sources of the LED lamp chip could effectively reduce the chip junction temperature by 8.249℃ while appropriately increasing the spacing between LED lamp chips could also effectively reduce the junction temperature by 0.5℃.

    New Type of Graphical Password Study Based on the Elegant Label Algorithm of Tree and Unicyclic Graph
    HUANG Ze
    Electronic Science and Technology. 2019, 32(3):  77-81.  doi:10.16180/j.cnki.issn1007-7820.2019.03.016
    Abstract ( 444 )   HTML ( 2 )   PDF (743KB) ( 73 )  
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    In order to solve the problem of easy memory and security of passwords in traditional authentication methods, an elegant labeling algorithm for tree and unicyclic graphs was proposed, which was further used to construct a new type of graphical password based on elegant labeling. The algorithm combined graph structure and number theory, iteratively traversed the specified elegant solution space until the corresponding adjacency matrix satisfied the elegant objective function or finished when the corresponding elegant space traversal was completed. This paper presented the algorithm design steps and carried out the algorithm test and analysis. The results showed that almost all the tree and unicyclic graphs within the 16-point range were elegant. Only some of the graphs were non-elegant. According to the results, two theorems and one conjecture were obtained, which provided a basic data set based on elegant labeling for the new graphical password.

    Same Location Guidance Algorithm of Measurement Equipment Base on the Modified Least Square Method
    PANG Yuefeng,MA Zhanshun,ZHANG Jianing,ZHANG Qian
    Electronic Science and Technology. 2019, 32(3):  82-86.  doi:10.16180/j.cnki.issn1007-7820.2019.03.017
    Abstract ( 366 )   HTML ( 4 )   PDF (570KB) ( 35 )  
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    When the measurement and control equipment tracks and measures the flying target, it is difficult to capture the flight target with the high tracking accuracy equipment. Generally, by the guidance of device with low tracking accuracy, the antenna approaches to the target and then turns into self tracking mode. Therefore, the mutual guidance of the station measurement equipment is an important mean for target acquisition. Directing at the technical requirements that high precision measurement equipment was guided by the low precision measurement equipment, this paper proposed an algorithm for real-time correction of low-precision equipment tracking data by using high-precision equipment tracking information when two sets of monitoring and control equipment shared the same target. The algorithm realized real-time estimation and extrapolation of trace residual and improved the accuracy of same station guidance. Finally, the experiment the photo-electric theodolite guided by the telemetry equipment. It is verified that the processed telemetry data can guide the photo-electric theodolite to capture the target. Finally, telemetering equipment was used to guide the photoelectric theodolite to carry out experiments. The verification showed that with use of the corrected telemetry equipment tracking data,the photoelectric theodolite could effectively capture the targets.

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