Mathematical modeling and analysis of the operating modes of a slag transporter in a converter shop

Abstract

Purpose. To develop and investigate, using mathematical modeling, the dynamic modes of a four-motor DC electric drive for a slag car, and to justify the structures of the automatic control system for the tractive force of the traction motors using single- and double-integrating control systems, which ensure stable operation of the electric drive and eliminate wheel slip under asymmetric loads. Methodology. A systematic approach has been adopted to study an electromechanical object as a complex, multi-coupled system. Methods from the theory of electric drives are used to analyze electromechanical processes; principles from the theory of electrical machines are used to describe electromagnetic processes in electric motors; classical principles of vehicle dynamics (traction balance, resistance forces, limit modes under conditions of traction and overload); scientific principles of theoretical electrical engineering; mathematical modeling in the MATLAB/Simulink environment;  mathematical analysis (use of the operator form for writing equations and transfer functions); theory of automatic control systems (methods for designing closed-loop automatic control systems, evaluation of system performance); analysis and synthesis of control systems (comparative analysis of various control modes and algorithms). Originality. An electromechanical model of a four-motor drive mechanism for a slag truck has been developed, taking into account the nonlinear interaction of the wheel sets with the rail guides. An analysis of the circuits and operating modes of the slag car’s electromechanical system under variable loads was conducted. It was established that independent control of the drive systems for the driving wheel pairs and the introduction of an integral component into the external control loop for electric driving force prevent the vehicle from slipping. Scientific novelty. A mathematical model of the electromechanical system of a four-motor electric drive for a slag car has been developed, which accounts for the uneven load distribution between the axles, the nonlinear characteristics of wheel-rail adhesion, and the mutual influence of the drives during the application of tractive force; the patterns of how the structure of the automatic EMF control system and the type of controller influence the occurrence of wheel-set slippage modes in a four-motor electric drive of a slag car under asymmetric load conditions have been established; an improved approach to designing control systems for a four-motor electric drive of a slag car has been developed by justifying the feasibility of using individual electric motor control loops with proportional-integral controllers for each drive, which ensures the elimination of static error and the prevention of wheel-set slippage. Practical value of the results obtained lies in the possibility of applying the developed mathematical model and the research findings to improve the operational efficiency of slag trucks in the converter shops of metallurgical enterprises.