| In this paper, the modeling and simulation of a coal flow control system for the longwall scraper conveyor is presented. The coal flow on the scraper conveyor, it is controlled by the following variables: the coal flow, advance speed and cutting speed of the longwall shearer. The electrical drive system of the longwall scraper conveyor together with the electrical drive system of the advancement and the cutting mechanism of the longwall shearer are done by means of induction motors. The control of speeds and electromagnetic torque of induction motors is realized by using sensorless vector control systems. Within these control systems, the estimation of position and of components of the rotor flux space-phasor, as well as the rotor speed of the induction motor, is done by an extended Gopinath observer. The advantages of a coal flow control system are control of productivity and also that electric motors of the flow of transport can be optimally chosen, leading ultimately to a much lower consumption of electricity for coal extraction. Modeling and simulation of control systems is done taking into account the mathematical equations that make the connection between constructive and functional parameters of the longwall shearers with the features of the strata of mining coal, specifically the coal deposits from the Jiu Valley, Romania. |
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