Features of the use of brushless motors in traction rolling stock

The review study examines a range of technical, design, and operational features of modern brushless valve and asynchronous traction electric machines, which are widely used in locomotive construction and transport electric drives. The object of research is electromagnetic, thermal, and energy processes occurring in brushless valve and asynchronous traction motors during their operation in traction rolling stock systems. The design features of brushless traction motors are analyzed, which are characterized by high energy efficiency, increased specific power, the absence of a mechanical collector, as well as the ability to provide wide ranges of torque and speed control while minimizing maintenance. The specifics of working processes in valve and asynchronous motors have been identified, which are determined by the principles of electromagnetic conversion, control methods, and the response of an electric machine to variable loads. Compare the features of electromagnetic torque formation, commutation, and thermal modes of these motors in traction systems. Special attention is paid to the issues of regulating the rotation speed of asynchronous traction motors, which is implemented using frequency converters with scalar, vector, and direct control methods. The advantages of vector control, which ensures dynamic stability and maximum utilization of the motor's overload capacity in traction and recuperation modes, have been identified. The structural and technological features of designing asynchronous traction motors for locomotives have been studied, in particular the requirements for the magnetic system, rotor strength, cooling systems, and electrical insulation materials. The trends in the development of modern traction electric machines are summarized, in particular, the introduction of energy-efficient materials, the expansion of the operating frequency range, the improvement of thermal reliability, and the integration of the motor with power electronics into single electromechanical modules.