Power supply device for onboard auxiliary circuit of DC electric locomotive: scheme of the power part and methods to form the output voltage

Annotation: An article provides a brief analysis of the circuits of semiconductor converters used to power the auxiliary circuits of DC electric locomotive and proposes the scheme of power part of the device that is different from the widely spread ones. The author investigates characteristics of the device in static mode. The device comprises a capacitive divider of input DC voltage of the three-phase half-bridge autonomous voltage source inverter and three-phase transformer with a specific winding connection scheme III/Y. A comparative consideration of the energy characteristics of the device at different methods of pulse width modulation is carried out. The use of catenary voltage, the efficiency, the harmonic composition of currents and voltages, the values of the total harmonic distortion and power factor were taken into account. Cost reduction for the set of power switches of the inverter up to 1.5–2.0 times in comparison with the known technical solutions is achieved.

Keywords: autonomous voltage source inverter, three-phase transformer, dc electric locomotive, supply of auxiliary circuits, pulse width modulation, harmonic composition