Development of an algorithm for defining thyristors opening angle value at the new configuration of grid commutation of reversible converter arms of electric locomotive

The article presents a new approach in the application of a diode discharge arm which is aimed at increasing the energy indicators of traction mode of AC locomotives. The method implies the utilization of electromagnetic energy stored in the commutate current circuit for closing exhausted thyristor arms of traction converters through a buffer contour provided by the discharge arm.A mathematical simulation of electromagnetic processes of the standard and proposed converters has been performed. The analysis of the results allows to find the most optimal value of thyristor arms opening angle when the discharge arm closes fully the exhausted thyristor arms in compliance with the condition of increasing the power factor of the electric locomotive.The developed control method of the proposed converter is presented by a table of pulses fed to the thyristors electrodes, as well as by the algorithm of point-of-time calculation of the impulses generation.