Modeling waveform distortion produced by DC locomotive conversion system. Part 1: Locomotive model

The paper presents a new high computational efficiency model for the calculation of the waveform distortion caused by the locomotive E404P when it is supplied by a 3 kV DC voltage. It follows a previous paper about the same locomotive supplied by 2×25 kV AC voltages at 50 Hz. Here, the adjustable speed drives of this locomotive, used to feed the AC motors, are configured as multistage DC/DC/AC PWM-controlled converters. The proposed model is based on the switching function approach and use the iterative harmonic and interharmonic analysis procedure. The waveform distortion evaluated in different operating conditions shows the good accuracy of the results obtainable by means of the new model, compared with those of time domain simulations. The new model is suitable to be used in the framework of a comprehensive model of the railway system, including AC/DC substations, like that presented in the Part 2 of this paper with reference to the Italian railways system.