JH—14型礦用回柱絞車設(shè)計(jì)【說(shuō)明書(shū)+CAD】

JH—14型礦用回柱絞車設(shè)計(jì)【說(shuō)明書(shū)+CAD】,說(shuō)明書(shū)+CAD,JH—14型礦用回柱絞車設(shè)計(jì)【說(shuō)明書(shū)+CAD】,jh,14,型礦用回柱,絞車,設(shè)計(jì),說(shuō)明書(shū),仿單,cad Study on Digital DC Hoist System of Mine-shaft LI Qixuan, SUN Huoran, MU Taisheng, WANG Bo (School of Resources friction Hoist; variable flow control; frequency-variation control; PLC 1 Introduction With the continuous booming of raw material market in China, the production and development of various mines is faster than before. Due to the reduced mineral resource in the shallow underground, existing mines are exploiting deeper part. Currently most mines are using the analog electronic control which is a before 1990s technology. These hoists have reached the end of their service lives and the electronic control parts need to be renovated 1 . The mine shaft hoist equipment is used for hoisting coal, ore, personnel, equipment and materials up and down the shaft. As a throat of the underground transportation, it plays a vital role in the whole production process. The least would be the influence of production and the most would be the safety of workers if there were any hoist failure. Traditional hoist system uses electronic motor rotator tandem with resistor classified speed control or serial speed adjustment TKD control. The disadvantages of tandem resistor classified speed control are big loss of rotation, low speed adjustment efficiency, slow dynamic response, difficult to adjust the speed steplessly and an unsmooth speed adjustment. Moreover, the tandem resistor speed control interfere the electricity network with a narrow speed adjustment scope and hence a low power factor. With the development of electricity and electronic technology in China, the disadvantages of traditional hoists are becoming more obvious and have impeded the development of mines. For the purpose of improving the technology in the mines, training some professional on site personnel, reducing the production cost and enhance the mines competition ability, a reliable, safe, stable PLC system is developed using the advanced digital technology, automatic control theory, on site international popular general line control method and the fuzzy accurate control. This system has the advantages of simple and convenient installation, easy operation and high automation level. 2 Disadvantages of Traditional Hoist System 90% of existing hoist systems in China adopts AC coil asynchronous motor rotator tandem resistor system. The main problems with this system are as following: 1) Low speed adjustment performance, high energy consumption and low efficiency. 2) Limited system adjustment capacity and slow dynamic response due to the adoption of TKD electric control system. 3) Low reliability and difficult to maintain 2-3 . 3 Characteristics of Digital DC Hoist System The digital DC hoist system has the following characteristics: 1) Adopting multi-digit display in place of traditional depth indicator, the system can display the running speed, armature current, excitation current and the location of the hoist equipment. This makes the hoist system more compact and the display more accurate. 2) The adoption of DC driving improves the working environment, reduces energy consumption. This is 894because a DC motor can generate electricity during the deceleration and braking process by changing the moving energy into the electricity when it is running in four-quadrate. 3) Using a converter to supply power to the motor. This control scheme adopts two parallel 6 pulse standard power conversion (see Fig.1). This can reduce the current disturbance and lower the negative converter influence on electricity network. No need to add power factor compensation device because of this systems high power factor. The 12 pulse control scheme has the advantages of fast current direction switch, fast speed loop response, smaller torque disturbance decrease and higher control precision. Fig.1 The 12 pulse control scheme 4) Two sets of independent PLC. 5) Adopting multiple encoders for location feedback at different control points. PLC compares and analyzes these data to respond quickly wherever has a fault, which ensures the control systems different control command based on different situations. The location tolerance of the whole system is 1%. The stopping precision tolerance is 2 cm and the speed precision tolerance is 0.01m/s. 6) Complete protection functions. This system has the monitor protection, min PLC protection and converter transmission system protection etc. 7) The simulated monitoring of the whole system is realized through the computer and the corresponding software. The human-machine interface greatly increases systems operational and maintenance functions. The central computer monitoring system adopts three dimensional animation which is very close the practical situations. The Chinese version makes the whole system easy to understand and simple to operate. 8) The complete automation of loading, lifting and unloading of ore in a dustpan can be realized. 8954 System Compositions Fig.2 The digital DC hoist system composition diagram The digital DC hoist system consists of computer system (PLC), transmission system, monitoring system, upper level computer system, control system, transducer system, main motor and auxiliary equipment. The computer system is the core. PLC adopts SIMATIC S7-300 of SIEMENS. Although S7-300 is a modularized small scale PLC, it can meet the middle scale performance applications. Modularization and no exhaust fan structure, easy distribution and simple to grasp makes S7-300 the major convenient and economical solution for various small and middle scale performance applications. The main CPU adopts CPU314FIM which is an integrated digital and analog input/output compact CPU. With a 24K EMS memory, it is applied to the equipments that demand fast reaction and special functions. The monitoring CPU adopts CPU312FIM which is an integrated digital and analog input/output compact CPU with a 6K EMS memory. The output module adopts 16 points digital output, SM 322 module of 24 VDC while the input module adopts16 points digital output, SM 321 module of 24 VDC. Analog input/output module adopts SM 334 module that is 4 lines input, 2 lines output. The analog input module adopts SM 331 module which is 4 lines input. This is just like a humans nerve system: the information from the transducer get into the computer system through different channels; then the computer system analyse, computer comprehensively on these external signals and give the control command to execution system for corresponding running functions. Digital DC control DC motor driving control system adopts 2 high performance micro-processor and their corresponding interface circuits(see Fig.3). It uses computer software programming to complete the adjustment, monitoring and diagnosis, data communication of armature circuits. The composition and the principle are as following: 1) Given speed value. Given speed value and additional given value can be selected based on the given parameters in a hoist control system, the given values are one of the output method which can adopt 0-10V , 0-20V , 8964-20 MA given by PLC. Usually 100% given value corresponds to the maximum motor rotating speed. The maximum and the minimum given values are restricted by parameters or connectors and are then sent to slope function generator. 2) Ramp function generator is given by PLC. The setting speed value is changing up and down and is changed to a certain signal changing with time by the ramp function generator. The acceleration and deceleration time can be set separately. Besides, the starting and ending curves can be set and then function on the speed adjustors directly. 3) The practical value. Generally the hoist speed is measured by the encoder on the motor axis and is changed to a digital amount through parameter match; after speed filtering, it acts on the speed adjuster. 4) Speed adjuster compares the given speed value and the actual value and perform PID calculation according to the difference, then output the result as a current to the current adjuster. The speed adjuster is a proportional integral (PI) adjuster which can select differential (D). Manual optimization method optimizes the complete speed adjusting system performance indexes with certain stable surplus. Fig.3 Digital DC control DC motor driving control system 5) Current adjuster. Hoist system transmission belongs to soft transmission and the sudden change of torque should be avoided. In addition, the change of amateur current (di/dt) is limited, therefore, the output of speed adjuster must go through current change limiting tache after current limiting (or torque limiting) before going to current adjuster. The speed adjuster compares the given current value and the actual current value and then performs PID calculation on the difference. After adding the preset current value, the result is applied directly on the trigging device. The current adjuster has independent scale magnifier Kp and integral time constant Ki. The scale or time can be cut (pure scale or integral adjuster).Kp and Ki can be determined by manual optimization with the principal that the current loop performance is the best. The actual current value firstly goes through the inspection of current transducer by the three phases AC. It is then commutated through electric switch and the signal is collected by load resistor. At last it is sent to current adjustor after module/digit change. 6) Current pre-controller. The current pre-controller in the current adjusting circuit is used to improve the adjusting systems dynamic response and reduce the current response time which is usually 6-9 ms. The pre-controlled value and the given current value is related to the motors reverse electricity energy. The rapid change of trigging angle when in continuous and periodical working conditions and when changing torque signal should be considered too. 897 7) Loop less current control logic. As a four quadrate device, this loop less current control logic works with current adjusting circuit to complete the logic control when changing the torque signals. When necessary, block a torque direction with the help of parameters. 8) Trigging device. Trigging device develops the trigging pulse of crystal brake tube. The synchronous signals come from the self-determined loop which is synchronous with the main circuit voltage. Therefore it is irrelevant to the power supply phase of the electronic board. The trigging pulse timing is determined by the speed adjuster and pre-controller output and controls limits through parameters. The function of monitoring system is monitoring and protection. When there is an abnormal situation in hoisting system, the monitoring system can detect and send signals to the computer system. The upper level computer system is a human-machine interface, which is used for display various important hoister running parameters, fault information, production statistics, speed chart, etc. The control and execution system is mainly composed of intermediate relay and contactor, which executes different commands, sent from the computer and controls every equipment in the hoisting system. The transducer system senses the running status of every equipment of hoister, and feedback the sensed signals to the computer system. The main motor is an important equipment of the hoist. It drives the roller to rotate and therefore the movement of cage or dustpan in the shaft. The auxiliary equipment provides necessary support to the running of cage or dustpan. It includes hydraulic station, cooling ventilator, lubricating station, cooling ventilator transducer, etc. 5 Programming Design Programming design adopts modularized programming. The complete programming is divided into major programming, cage programming, dustpan programming, report forms programming, upper level computer programming and main control and monitoring control communication programming. Different sub programming within the main programming can be loaded according to different operating conditions, which increases the utilization of PLC under the normal running of the complete system. LAD programming language is adopted. Compared with function module language and sentence form language, the complete programming is easy to understand and convenient to learn and maintain. 6 System Application Longqiao Iron Mine locates in Longqiao county, 25 km southeast of Lujiang City. The mine is a large underground magnetite with high ore grade and easy distractibility. The side products are copper concentrate abd sulphur concentrate. The deposit of iron ore is103.637 million tons. The accompanying copper deposit is 90144 tons, the accompanying sulphur is 2.786 million tons. The occupancy rate of magnetic iron is 84%. The mine owns a set of 1400kw automatic digital DC hoisting system with maximum daily ore lifting of over 6000 tons. This system can realize complete automatic control of loading-lifting-unloading. The system can judge the preferential level according to the different sequence of signals from different levels. The application of this digital DC hoist system has created huge social and economical profits for this mine. 7 Conclusions The digital DC hoist system runs safely and reliably with small maintenance. Its high dynamic and resting performance indexes realizes the complete digital control and with complete protection devices. The system can communicate with the whole enterprise net to realize mine automatic control management, long distance monitoring and diagnosis. It has extensive application prospect in the shaft hoist system and will create huge social profit. References 1 Li Hong, The performance Characteristics and Application of Mine Shaft Hoist Electrical Control System. Metal Mine, 2003 (4):54-55(in Chinese). 2 Wang Qingling, Gong Youmin. Modern Mine Shaft Hoist Electrical Control System. Beijing: Mechanical Industry Publishing Company, 1996(in Chinese) 3 Wang Shunhuang, Shu Diqian. Intelligent Control System and Its Application. Beijing: Mechanical Industry Publishing Company, 1995(in Chinese). 898