The Study On The System Of Variable Frequency Control In-line Monitoring For Mine Fan

With the development of electronic technology, the automation level of coal mine fans system has been improved, and the running of equipment is more secure, reliable,the efficiency of the air blower system has been improved at a certain extent. To further enhance the efficiency of the air blower system and achieve energy-saving emission reduction of coal enterprises, this paper puts forward design ideas of coal mine air blower systems on-line monitoring frequency conversion control system based on the Programmable Logic Controller (PLC) and the inverter. On the basis of study of centrifugal pump characteristic, this paper expounds the principle of energy saving with frequency control and analyses the economics of the frequency control used in the mine fans system.The fans device takes responsibility for the transportation of fresh air to the mine, exhaustest the dust and dirty air in coal production, which undertare the important task of ensuring safety of production. According to production needs to pressure, wind speed, air flow, temperature and other indicators to control and adjust to meet the process requirements and operating conditions. The most common means of control is the adjustment damper and the size of the baffle opening to adjust the controlled object. In this way, regardless of the size of the production demand, fans have to run at full speed, ultimately, the energy lose through the throttle of the damper and baffle. In the production process, not only limited control precision, but also resulted in considerable loss of energy waste and equipment, accordingly, resulte from increased production costs, shorten equipment life, equipment maintenance, repair stubbornly high costs. There is a large starting current, mechanical shock, poor electrical protection when most fans run by the way of the direct drive of induction motor, which not only affects the equipment life, but also can not instantaneous operates to protective equipment when the load Appear mechanical failure, fans and electrical damage was always burned at the same time.The design control the Inverter using PLC by the method of communication, In order to solve the above problems existing in the traditional fan. Just changing the PLC program, you can adjust the system's control strategy and operation mode easily. PLC system is the core of the whole control system, the control system collects parameters from the various sensor using PLC peripheral modules, with which control start stop and switch the fan after the internal signal dealing. Main program PLC main program includes the program of the system initialization the starting program of damper motor,the anti-wind program of fans,the collecting program of analog (pressure, wind, vibration, temperature, etc.),the program of shutingdown and alarming. The controlling system of PLC controls the frequency converter to realize the regulation of fans after realizing online detection of fans performance.Through the study of this paper, the PLC automatic control and frequency conversion technology applied to fans control and monitoring, it has practical significance to improve the safety and efficiency of coal mine fans systems.