| Abstract |
The problem of harmonic pollution due to traction chopper is analyzed in order to have a large amount of informations which take into account also random variations. At this aim, firstly the behaviour of a classical chopper for dc traction is examined, with emphasys on the harmonic content and on the links between chopper current and control logic. Then a harmonic model of the traction chopper is proposed. lt takes into account the presence of non-ideal operating conditions, deriving from late or early firings. Finally it is shown how the proposed model well fits in a probabilistic approach, which seems to be particularly suitable for evaluating current distortion in de traction systems. |
