The ways of development and improvement of DC traction power supply system by increasing the voltage in the traction network up to 24 kV, and its adaptation for high-speed lines are examined. Mathematical model of the dynamic electromagnetic processes in electrical circuits with semiconductor converters is proved. The features of the electromagnetic processes in semiconductor converters are examined. Substantiation of electromagnetic compatibility of traction system DC power supply with increased voltage 24 kV in the traction network with the environment, infrastructure, communication links and chains of railway automation is showed.Keywords: traction power DC supply system with increased voltage 24 kV in the traction network and adapting it to high-speed lines, electromagnetic compatibility, electromagnetic processes in electrical circuits with semiconductor converters.
The topologies of voltage source inverters implicated now and prospective for needs of traction frequency converters are considered. The two-level and three-level with clamped diodes voltage source inverters are shown to be an optimal choice due to a row of reasons. The equations for numerical and analytical approaches of power losses evaluation are analyzed. The power losses evaluation of the chosen two- and three-level inverters is carried out. The thermal equivalent circuits of the single semiconductor device and power module on its base for the two inverter topologies are presented. The temperatures of transistors and diodes in the steady state are determined. The boundary values of the switching frequency delivering equality of the maximum temperatures of two- and three-level inverters are extracted.Keywords: voltage source inverter, thermal behavior, thermal equivalent circuit, power losses, switching frequency, modulation.
This paper analyzes the different approaches to the technical maintenance of electric subway trains based on the safety of complex transport systems. The results were obtained from using the genetic algorithm.Keywords: electric trains, technical maintenance, genetic algorithm.