Mathematical model of traction electric drive of a diesel locomotive wheelset with electric boost system of coupling qualities

Abstract

A mathematical model of the traction electric drive of a diesel locomotive wheelset has been developed, which allows for theoretical analysis of the increase in coupling qualities when exposed to electric current on the contacts of wheels with rails. For mathematical description of the processes occurring in the electric motor, a classical calculation method is used, which is based on a generalized electric machine. When studying the electric drive, it is not necessary to take into account elastic bonds in the mechanical part, therefore it is presented in the form of a one-mass calculation scheme. The processes occurring in the electric drive system are influenced by various factors. The tangential thrust force, which determines the moment of static load, can have different values determined by resistance to the movement of the train. The greatest traction force depends on reduction of the load on the wheelset in traction mode and on the calculated coefficient of adhesion of the wheels to the rails, which has a non-linear falling character, especially in the zone of low speeds. Contamination of the rolling surfaces of wheels and rails leads to decrease in the physical coefficient of adhesion. The supply of electric current to the contact zones of wheels with rails increases the coefficient of adhesion, the limit values of which in various contact states according to the degree of contamination are described by the corresponding regression mathematical models.