2014 Vol. 40, No. 9

Display Method:
Design of hydraulic support controller for automatic working face
JIANG Chunyue, TIAN Muqin, SONG Jiancheng, XU Chunyu, YANG Shihua, CHAI Wen, YANG Dong, DONG Guangzhuai
2014, 40(9): 1-5. doi: 10.13272/j.issn.1671-251x.2014.09.001
Abstract:
For problem that hydraulic support controller was operated manually in most coal mines at present, which led to low working efficiency and poor operation safety, a hardware design scheme of hydraulic support controller for automatic working face was introduced, and realization schemes of centralized control function and self-diagnosis function of the controller were expounded. The controller, which adopts dual controlling cores and communication mode of dual RS485 buses, can monitor, process and upload information real-timely including roof pressure of hydraulic support, pushing displacement and position of shearer, and realize automatic shearer tracking, support pulling and support pushing according to technical command from terminal controller. The controller also realizes self-diagnosis function by use of communication mode of I2C bus, which can real-timely monitor and correct fault action signals of hydraulic support. The results of industrial test on the ground and fault simulation experiment verify correctness of design scheme of the controller.
Application of unequal interval grey model in mining subsidence predictio
LIU Weipu, TAN Zhixiang, DENG Kazhong
2014, 40(9): 6-10. doi: 10.13272/j.issn.1671-251x.2014.09.002
Abstract:
For problems that mining subsidence prediction by use of gray model was only for one point at present and lacked overall subsidence prediction of working face as well as checkout of prediction accuracy, mining subsidence data was taken as research object which was monitored by surface observation station on strike line and dip line of working face, and interval of adjacent monitoring time was taken as weight to establish an unequal interval grey model for predicting subsidence value of the surface observation station at the next moment, thus subsidence curves of the strike line and the dip line were gotten. A parameter calculating method based on probability integral method was used to verify prediction accuracy of overall subsidence of working face. The difference between parameters calculated by use of prediction data and the ones by use of actual data is small, which verifies feasibility of the unequal interval grey model applied in prediction of overall mining subsidence.
Research of 3D modeling method for mine roadway based on Web
JING Yongbin, XIONG Shumin, LIU Xiaoming
2014, 40(9): 10-14. doi: 10.13272/j.issn.1671-251x.2014.09.003
Abstract:
In view of problem that most of 3D modeling methods for mine roadway are based on stand-alone computer and it is difficult to share the models via Web, the paper discussed an implementation method of roadway modeling applying 3D Web graphics technology. The method gets section 3D line through 3D coordinate transformation of bottom centerlines and section parameters, uses section modeling algorithm to establish triangle strip 3D model of roadway; uses HOOPS 3D flow control embedded in a Web page and HSF stream file of 3D model to achieve network publishing of 3D model of roadway, and achieves access and interaction to large-scale 3D model of roadway with the help of network 3D graphics technology and browser.
Research of conformance testing platform for WIA-PA wireless communicatio
SHI Baoku, ZHANG Xianghui
2014, 40(9): 15-18. doi: 10.13272/j.issn.1671-251x.2014.09.004
Abstract:
The paper analyzed WIA-PA communication protocols and conformance testing, and designed conformance testing platform for WIA-PA wireless communication according to WIA-PA communication protocols. It elaborated process of forward testing and reverse testing by a test case. The actual test results indicate that the conformance testing platform can detect whether the device meets WIA-PA standard protocol, and provide reliable assurance for application of WIA-PA equipment in actual industrial field.
Research of integrated architecture of coal mine production system and its standardization problems
PAN Tao
2014, 40(9): 19-23. doi: 10.13272/j.issn.1671-251x.2014.09.005
Abstract:
The paper summarized promotion effect of new technologies to coal mine production system from digitization, informatization, automation, intelligentialize and standardization, analyzed integrated architecture of coal mine production system, and divided layers of the system. Then it described main problems solved by each layer and its service content, confirmed integrated framework of the system initially. It also pointed out the integrated framework should play a supporting role for the application system through hardware and software infrastructure specially. In the end, the paper discussed problems about information standardization, and pointed out that standardization is the fundamental way to solve the problems of data exchange and system integration.
Analysis of influence of hydraulic support resistance of large mining height on rib fall of coal wall under the second mining of residual coal
WANG Yuanjie, TIAN Xiao
2014, 40(9): 24-27. doi: 10.13272/j.issn.1671-251x.2014.09.006
Abstract:
Based on project background of the second mining working face of Shenghua Coal Mine, the paper explained mechanism of rib fall of coal wall of the second mining working face of residual coal, analyzed cases of rib fall of coal wall under different support resistances by theoretical calculations and computer numerical simulation, compared effect of the support resistance on the rib fall of coal wall under the condition of residual coal and entity coal, and drew the conclusions as follow: ① The extent of rib fall of coal wall decreased with the increase of support working resistance, and there was a linear relationship between the maximum depth of rib fall of coal wall and supporting strength, and the extent of rib fall of residual coal wall is much larger than the extent of rib fall of entity coal wall under the same working resistance. ② In the condition of entity coal, the extent of rib fall of coal wall is not serious when working resistance reached 8 000 kN. But in the condition of residual coal, the working resistance must reach 9 000 kN, then the roof falling and breakage depth of coal wall can be controlled. At last, the support resistance of the second mining working face of Shenghua Coal Mine was determined as 9 000 kN.
Analysis of reform measures of lightning protection of a mine
DONG Xinsheng, ZHANG Dong, TAO Fengyuan, WANG Shirong, GONG Ruibang
2014, 40(9): 28-31. doi: 10.13272/j.issn.1671-251x.2014.09.007
Abstract:
In view of problem of unefficient effect of differentiated lightning protection measure adopted according to lightning distribution maps of 220 kV line of a mine, impact of wind speed on performance of lightning shielding failure of line was analyzed. The following reform measures of lightning protection were adopted combining with wind speed, direction and lightning distribution maps: install line arresters along the lee side of lines perpendicular to the wind direction to defend shielding failure; install anti-low grounding resistance and line arresters in areas which are belong to hazardous areas and whose lines are perpendicular to the monsoon direction to defend counterattack and shielding failure; reduce grounding resistance of tow in areas which are belongs to hazardous areas and not affected by the monsoon to defend counterattack. The actual operating results show that the lines have good lightning protection performance after reform.
Design and evaluation of capacitive reactive power optimization in substation DC system
HUANG Yuansheng, DAI Xinbo, CUI Yong
2014, 40(9): 32-35. doi: 10.13272/j.issn.1671-251x.2014.09.008
Abstract:
In view of problem of misoperation of protection device caused by DC system grounding fault which often appears in substations, the concept of capacitive reactive power of DC system was proposed, and an optimized scheme of centralized power supply of DC system was designed applying optimization method of capacitive reactive power. The optimization scheme reduces DC line-to-ground capacitive character, and achieves the purpose of reducing reactive power by optimizing circuit trail on the basis of meeting supply reliability. It solves the misoperation problem of protection device and improves operating efficiency of DC system. Finally, the effect of the reactive power optimization scheme was evaluated to verify its reliability, security and economical efficiency.
Distribution law of UHF electromagnetic field strength in rectangular tunnel
CHENG Tingting, WANG Xiaosong, HUO Yu
2014, 40(9): 36-38. doi: 10.13272/j.issn.1671-251x.2014.09.009
Abstract:
The distribution law of UHF electromagnetic field strength in rectangular tunnel was studied by use of geometrical optics model and experimental data, and conclusion was obtained: there are apparently different electromagnetic field distributions when transmitting antenna is located in different positions of a tunnel section. When the antenna is in the middle of the tunnel, the fast fading convergence speed is the fastest and received electromagnetic field strength is the maximum. The electromagnetic field strength exhibits a nearly cosine scattering distribution, while it distributes relatively even when the location of transmitting antenna is nearby the tunnel wall. The conclusion can be used to predict effective coverage range of electromagnetic field in tunnels, and is useful for design and detection of cellular personal mobile communication network in tunnels.
Research of underground OFDM channel estimation algorithm
SUN Cuizhen, MAO Xinrong, MA Yanjun
2014, 40(9): 39-43. doi: 10.13272/j.issn.1671-251x.2014.09.010
Abstract:
In view of problems of complex underground channel environment and increasing of noise and error rate caused by multipath effect, a system model of orthogonal frequency division multiplexing was established, and the least squares error estimation algorithm and the minimum mean square error estimation algorithm were researched. Based on the rectangular pilot assignment, an estimation algorithm was proposed which uses curve fitting algorithm in the time domain to estimate the data signal channel coefficients. The proposed algorithm does not require high accuracy of the channel coefficients of pilot signals, only requires the constructed function as close as possible to the real value compared with the interpolation algorithm. The simulation results show that the proposed estimation algorithm can greatly reduce implementation complexity, and estimation performance has't big change compared with the minimum mean square error estimation algorithm. Simulation results and theoretical analysis are basically identical.
2014, 40(9): 44-48. doi: 10.13272/j.issn.1671-251x.2014.09.011
Abstract:
Research of automatic detection algorithm of conveying belt deviation based on OpenCV
XU Huan, LI Zhenbi, JIANG Yuanyuan, HUANG Jianbo, HUANG Da
2014, 40(9): 48-52. doi: 10.13272/j.issn.1671-251x.2014.09.012
Abstract:
In order to improve real-time performance and precision of detection method of conveying belt deviation, an automatic detection algorithm of conveying belt deviation was proposed combined with the advantages of OpenCV. Firstly, the algorithm uses CCD camera to capture video stream image of conveying belt real timely, and pre-processes the video stream image. Then it uses improved Canny edge detection algorithm to detect image edge. Finally, it adopts Hough linear transform to extract the belt deviation characteristics, and determine whether the belt is deviation or not, and make alarming if deviation. The test results show that the algorithm is simple and effective, has high speed of operation, and realizes automatic detection of conveying belt deviation.
A new scheme of selective leakage protection of mine low-voltage power network based on differential variable of zero-sequence current
WANG Yanwen, LU Da
2014, 40(9): 53-57. doi: 10.13272/j.issn.1671-251x.2014.09.013
Abstract:
In allusion to low reliability and sensitivity of existing selective leakage protection devices used in mine low-voltage power network, a new scheme of selective leakage protection was proposed which was based on differential variable of zero-sequence current. In the scheme, differential variable of zero-sequence current is gotten at different measured points in each branch when single-phase leakage fault occurred in mine low-voltage power network. Lateral selectivity and fault section location of leakage protection are achieved according to differences of amplitude and phase of the differential variable between fault branch and normal branch. Simulation via Matlab/Simulink and calculation via Fast Fourier caused by Transform show that the scheme avoids influences by load capacity and initial phase angle of voltage of from power network and has high reliability and sensitivity of fault line selection and section location.
Fuzzy decoupling control of brine flow and temperature in frozen statio
LI Songgao, ZHENG Xiaoliang
2014, 40(9): 57-60. doi: 10.13272/j.issn.1671-251x.2014.09.014
Abstract:
In view of problem of low control precision of existing control method of brine flow and temperature in frozen station, a fuzzy decoupling control method of brine flow and temperature was proposed. Firstly, fuzzy control method was carried out on fuzzy control of flow and temperature according to different control accuracy of the brine flow and temperature. Then the decoupling control method was used for decoupling control of output flow and temperature through analysis and research of the coupling relationship between brine flow and temperature. The simulation results show that the control method can realize decoupling control of brine flow and temperature, and has high control precision without accurate mathematical model of brine flow and temperature.
Study of selected harmonics elimination control technology of multi-level inverter
YE Manyuan, LI Song, LI Bing
2014, 40(9): 61-65. doi: 10.13272/j.issn.1671-251x.2014.09.015
Abstract:
In order to analyze nonlinear method of selected harmonics elimination PWM technique of multi-level inverter in-depth, several solution models of iterative algorithm were established, solution characteristics of these models were studied, and deficiency of the traditional numerical algorithm in the selected harmonics elimination solution was analyzed and improved. Taking a seven-level inverter as an example, the calculated results in different wavebands of each iterative algorithm were given, and algorithm parameters and elimination effect were compared. The simulation results confirm that solutions of these algorithms are correct.
Research of fast inter-AP handoff algorithm
HAN Xiaoyu, HUANG Tinglei, LIN Ke
2014, 40(9): 66-70. doi: 10.13272/j.issn.1671-251x.2014.09.016
Abstract:
In view of problem that traditional underground cable scheduling system cannot meet mobility requirements, a fast inter-AP handoff algorithm applied in intelligent scheduling and management system for mine locomotive was put forward. The algorithm divides coverage area of access point, and uses the master interface and slave interface for communication and connection respectively, which effectively reduces time delay for terminal to switch between different wireless access points. The experimental results show that the algorithm can effectively reduce handoff latency, and it also has good performance when the signal is unstable.
Research of power factor control of double-variable cycloconverter double-fed motor
GAO Manman, DU Qingnan
2014, 40(9): 70-74. doi: 10.13272/j.issn.1671-251x.2014.09.017
Abstract:
Mathematical model of double-fed motor was analyzed and relationship between stator current and rotor current of the motor was derived theoretically. Double-variable cycloconverter was used to provide frequency conversion excitation power for double-fed motor, and rotor current was controlled by controlling amplitude and frequency of output voltage of the converter. The impact of rotor current on stator power factor of double-fed motor was studied experimentally, and conclusions was derived that power factor of the motor can be adjusted by controlling rotor current.
Suppression strategy of circulating current of modular multilevel converter based on proportional complex integral controller
SONG Pinggang, JIANG Lang, LI Yunfeng, DUAN Chengting
2014, 40(9): 74-78. doi: 10.13272/j.issn.1671-251x.2014.09.018
Abstract:
A suppression strategy of circulating current of modular multilevel converter based on proportional complex integral controller was proposed according to double fundamental frequency negative sequence property of phase-to-phase circulating current of modular multilevel converter, which achieved circulating current suppression by setting resonant frequency of proportional complex integral controller to voltage frequency of power grid of double fundamental frequency negative sequence. In the strategy, there are no system parameters, no conversion of rotational coordinate and no current feedforward decoupling control in the proportional complex integral controller, so as to avoid the matter of poor control effect caused by changing system parameters. The simulation in Matlab/Simulink verifies correctness and effectiveness of the strategy.
Research of active disturbance rejection control for efficiency optimization of induction motors
MIAO Jingli, YU Xiang
2014, 40(9): 79-83. doi: 10.13272/j.issn.1671-251x.2014.09.019
Abstract:
For problems of complex control algorithms of existing efficiency optimization control method of motor, an improved dynamic decoupling control strategy based on active disturbance rejection controller was proposed. The active disturbance rejection controller leave out differential tracker, and adopts linear expansion of state observer and linear state error feedback control law, so that the control algorithm can be simplified. The results of simulation and experiment show that the control strategy can ensure efficiency optimization of the motor under light loading operation, which has strong anti-interference ability and robustness, improves dynamic response speed of the motor in efficiency optimization process.
Simulation and experiment of coal desulfurization model
XU Yunzhi, LIU Yannian, CHEN Ruicheng, CHENG Zhaojun, WANG Xuesong, DENG Xianming
2014, 40(9): 84-89. doi: 10.13272/j.issn.1671-251x.2014.09.020
Abstract:
A new coal desulfurization model of dielectric barrier discharge was built, and based on it, factors impacting on effect of desulfurization discharge, including dielectric types, dielectric thickness, gap spacing, supply voltage, power frequency were analyzed by simulation. The best fit solution of various factors was confirmed. Experimental data of coal desulfurization of dielectric barrier discharge was processed and analyzed, and it was found that the experimental results were consistent with the simulation results. Further inferences were made through comparative analysis of the discharge current spectrum and Lissajous waveform: discharge power can be improved through adding of coal; coal desulfurization effect of dielectric barrier discharge is reflected in low-order harmonics.
A strategy of neutral-point potential balance control and common-mode voltage suppressio
WANG Kezhi, ZHAO Wenhan, WANG Tao, YANG Gang, CHENG Guodong, GENG Yiwen
2014, 40(9): 90-93. doi: 10.13272/j.issn.1671-251x.2014.09.021
Abstract:
For problems that there are common-mode voltage, over voltage and neutral-point potential imbalance simultaneously in power supply of inverter to motor through long cable, generation mechanisms of common-mode voltage and over voltage were analyzed as well as effect of neutral-point potential imbalance on common-mode voltage. A strategy of neutral-point potential balance control and common-mode voltage suppression was proposed, namely adding the fourth leg to traditional three-level inverter, controlling current of the fourth leg to realize neutral point potential balance and optimizing SVPWM modulation strategy of main circuit to restrain common-mode voltage. Effectiveness of the strategy is verified by Matlab simulation.
Simulation research of the second order sliding mode observer of sensorless permanent magnet synchronous motor
DENG Xinzhong
2014, 40(9): 94-99. doi: 10.13272/j.issn.1671-251x.2014.09.022
Abstract:
For eliminating chattering caused by traditional sliding mode observer used in sensorless control of permanent magnet synchronous motor, a sliding mode observer based on the second order sliding mode control method was proposed to estimate position and speed of rotor of permanent magnet synchronous motor. The position and speed of rotor were estimated separately by traditional sliding mode observer and the second order sliding mode observer in Matlab/Simulink software under ideal condition and parameter perturbation condition. The results show that the second order sliding mode observer can obtain smooth curves of estimated position and speed of rotor under the condition of no low pass filter with smaller estimation error, which has better observation precision and robustness.
A distinguishing method of open-circuit IGBT of three-level NPC inverter
QIU Shiguang, LI Mei
2014, 40(9): 99-102. doi: 10.13272/j.issn.1671-251x.2014.09.023
Abstract:
For problem of large calculated amount of existing distinguishing method of open-circuit IGBT of three-level NPC inverter, all kinds of open-circuit states of IGBT were simulated, and the causes of bus neutral-point voltage deviation were analyzed, then a simple method to distinguish the open-circuit IGBT was proposed. The method achieves distinguishing of open-circuit IGBT by detecting bus neutral-point voltage and three-phase output voltage of inverter, which needs no extra hardware. The simulation results verify effectiveness of the method.
Design of mine-used ultrasonic transducer of wind speed and directio
LIU Lili
2014, 40(9): 103-106. doi: 10.13272/j.issn.1671-251x.2014.09.024
Abstract:
In order to monitor gas countercurrent leaded by coal mine gas outburst accidence, a mine-used ultrasonic transducer of wind speed and direction was designed based on principle of ultrasonic time difference method. The relationship between the wind speed and direction and the time difference of ultrasonic transmitting and receiving is applied to operate and obtain the wind direction and speed. The testing results show that the transducer has strong stability and high measurement accuracy, wind speed measurement range is 0.4-15 m/s, its error is no more than 0.3 m/s and wind direction measurement range is 0-360 degree, error is no more than three degree.
Design and application of frequency converter test system of mine-used hydraulic pump
RONG Xiang
2014, 40(9): 106-110. doi: 10.13272/j.issn.1671-251x.2014.09.025
Abstract:
An improved frequency converter test system of mine-used hydraulic pump was proposed in order to meet demands of performance testing and debugging of spare parts and repaired hydraulic pump after hydraulic pump was fault, and solve the problems that common hydraulic pump test system has low automation level, large workload on recorded data processing. Hydraulic system, frequency-conversion control system, information collection system and software system of the system were introduced in details. The system can quickly collect signals of hydraulic pump pressure, flow, rotational speed and torque, and can automatically complete efficiency test, impact test, load test, overload test and speed test of the hydraulic pump. The system has obvious saving effect with power recovery rate of 60% in full load and overload test.
Current situation of coal mine wireless communication technology and its development
XU Shouquan, XU Baoping, ZHANG Yangtai, WU Yu
2014, 40(9): 111-114. doi: 10.13272/j.issn.1671-251x.2014.09.026
Abstract:
Application status of various mine-used wireless communication technologies was analyzed, including wireless communication technologies of PHS, WiFi, TD-SCDMA, WCDMA and Femtocell. A mine-used WCDMA wireless communication system based on Femtocell was put forward according to environment characteristics of coal mine underground, key technologies and advantages of the system were introduced in details. Finally, development trend of mine-used wireless communication technology was summarized.
Application of mine-used TD-SCDMA wireless communication system in Lushuidong Coal Mine
XU Wei, GU Yidong, LI Jing
2014, 40(9): 115-118. doi: 10.13272/j.issn.1671-251x.2014.09.027
Abstract:
The paper introduced scheme selection, system composition and function characteristics of mine-used TD-SCDMA wireless communication system in details, and expounded application of mine-used TD-SCDMA wireless communication system in Lushuidong Coal Mine. The application results show that the system has stable and reliable performance, large capacity, good effect of calls, large base station coverage, and can meet needs of mobile communication in coal mine underground.
Monitoring system of explosion-proof rubber-tyred vehicle based on 3G communication network used in mine
DENG Wenge
2014, 40(9): 118-120. doi: 10.13272/j.issn.1671-251x.2014.09.028
Abstract:
For problems of huge construction cost and maintenance existed in a transportation monitoring system of explosion-proof rubber-tyred vehicle based on RFID technology, a monitoring system of explosion-proof rubber-tyred vehicle based on 3G communication network used in mine was proposed, and overall structure of the system and design scheme of communication terminal were introduced. The system can real-timely monitor running status of explosion-proof rubber-tyred vehicle through existing 3G communication network used in mine, which only need equip a communication terminal in explosion-proof rubber-tyred vehicle. The test rsults verify reliability and stability of the system. The system has run for 6 months without any fault in a coal mine.
Design of automatic identification system of coal and gangue for fully-mechanized coal caving working face and its applicatio
ZHANG Liang, NIU Jianfeng, DAI Gang, ZHAO Wensheng
2014, 40(9): 121-124. doi: 10.13272/j.issn.1671-251x.2014.09.029
Abstract:
An automatic identification system of coal and gangue for fullly-mechanized coal caving working face based on vibration signal was proposed, structure and working principle of the system were introduced and design schemes of software and hardware of coal and gangue identification device were expounded as well as identification algorithm. The coal and gangue identification device identifies coal and gangue according to different vibration signals of coal and gangue falling on hydraulic support. Electro-hydraulic controller controls hydraulic support act according to identification result. The system has been tested with contents of identifiability of coal and gangue and controllability of automatic coal caving process in a mine and applied in some mines, which gets better effect.
A wind tunnel test device for automatic calibration of multiple wind meters
HUANG Shouyuan, JIA Anmin, HUANG Junxin
2014, 40(9): 124-126. doi: 10.13272/j.issn.1671-251x.2014.09.030
Abstract:
For problems of manual adjustment of wind volume many times, complex operation, large time and laborious consumption of manual data reading and drawing and low calibration precision existed in traditional calibration methods of wind meter, a wind tunnel test device for automatic calibration of multiple wind meters was designed and structure and test principle of the device were introduced. The test result shows that the device can automatically adjust wind volume with steady wind by simple operation, calibrate multiple wind meters at a time with high calibration precision, and record, store and process calibration results, which is suitable for automatic calibration of low, medium and high grade wind meters.