Petrenko O. Scientific bases of a choice of optimum parameters and operating modes of cooling systems of asynchronous traction engines of electric transport

The thesis is devoted to the creation of scientific foundations for the selection of optimal parameters and operating modes for cooling systems for asynchronous traction motors of electric transport. An algorithm for solving the Hamilton-Jacobi-Bellman equation for the problem of the motion of an electric stock on a section of a track with a given profile and a traffic schedule is developed. That makes it possible to create an expert control system for motion. Features of this algorithm is the use of penalty functions to describe the restrictions imposed by the traffic schedule: the train reaches the destination point for a given driving time, the speed limit on the sections of the track, and the absence of train idle time during the movement. A single approach to penalty functions is also applied to introduce constraints on the adhesion. This approach allows to reduce significantly the costs of the estimated time and to simplify the procedures for calculating energy costs. A mathematical model is created to determine the efficiency of the traction drive. The model includes the determination of the main losses in an asynchronous traction motor, taking into account the saturation of the magnetic system, which is determined by the results of solving a recurrent nonlinear equation. Also, the model takes into account losses from higher harmonic stresses in copper and steel, mechanical and additional losses. The developed model takes into account static and dynamic losses in IGBT transistors and diodes of a semiconductor converter. A method for optimizing the parameters and operating modes of cooling systems for asynchronous traction motors of the electric stock is developed. It consists of the following main stages: determination of the optimum mode of the traction drive operation on the basis of the proposed expression of its efficiency; determination of optimum modes of movement of the electric stock by the criterion of minimum costs; solution of the traction problem of motion on a section of the track with a specified traffic schedule and the track profile, as well as the determination of the dependence of the change in losses in the elements of asynchronous traction engines in time; choice of parameters and operation modes of cooling systems for asynchronous traction motors, which determine the efficiency of the cooling and ventilation system of the electric stock; solution of the problem of relative minimization of the cooling system for asynchronous traction motors with a modernized criterion of economic efficiency based on the Weil method on the generalized golden section and the problem of analyzing the ventilation and cooling system of traction motors, which is based on the mathematical model of thermal motor conditions by the generalized equivalent thermal scheme.