The Research Of Asynchronous Motor Vector Control In Rotary Hearth Furnace Hearth Of Rotation

Rotary hearth furnace process is a very promising technology in current metallurgicalindustry. The control of rotary hearth furnace hearth rotating is a key linking in the process ofits smelting, and the reduction process is directly affect by the speed of motor driven in hearthrotating. In traditional rotary hearth furnace system, the rotation of hearth is usually controlledby motor, using preset parameters of artificial instruction, which can only rotate at a certainspeed. The dynamic performance of motor drive system is poor when controlled in this way,and it can’t adjust motor speed in accordance with real time reduction schedule, thusinfluences the process of reduction reaction to some extent.For this kind of situation, this paper applies high performance speed sensorless vectorcontrol into the rotation of the hearth. The article preliminary verified the feasibility of studyscheme by experiment simulating, and at the same time it provides a new way to improvetechnology level for the rotary hearth furnace process. The main research content can be listedas followsFirstly this paper outlined the characteristics of the rotary hearth furnace process and thecontrol mode and requirements of hearth rotating in rotary hearth furnace system, and thenintroduced the development of AC motor control, pointed out the present situation anddevelopment trend of the speed sensorless vector control of induction motor. Then putforward to apply speed sensorless vector control into the hearth rotating control system,illustrated the significance of study.Secondly the paper introduced the mathematical model of asynchronous motor and therotor field oriented vector control theory. With the detail introductions MRAS speedidentification in traditional speed sensorless vector control system, the paper proposed a wayof speed identification based on double parameters MRAS. And the paper analysis two kindsof speed identification scheme, through constructing the speed sensorless vector controlsystem simulation model. Finally the paper choosed the proposed double parameters MRASspeed identification method as the speed identification scheme to establish the speedsensorless vector control system.Thirdly the reduction process of the pellets containing carbon in Rotary Hearth Furnaceis studied in detail in this paper, and the real-time speed of the motor is deduced on the basisof the requirements for meet the reduction performance. In addition this paper puts forwardthe research of closed loop control of hearth rotating for the first time, and the speedsensorless vector control system which has established is applied to the hearth in the speedcontrol, then take the real-time speed of expression as a given speed signal of motor control.After studying the related reduction theory of carbon-containing pellet and under thecondition of reasonable assumption, the simulation analysis is carried out for the system. Finally the paper designed both hardware and software of the main part of the hearthrotating control--speed sensorless vector control system. The hardware part includes maincircuit, control circuit and peripheral detection circuit. The software design includes the mainprogram, the initialization program and the interrupt service routines, fault interruptsubroutine.