Polyphase sync. motor DC supply system - has electronic switches for winding phases controlled to one overlap when switching in and out

摘要

The circuit arrangement has a switch device to connect the winding phases of the armature winding to the mains dc voltage. This device comprises a number of electronic switches each assigned to individual winding phases. Switching logic controls the switches according to the angular position of the sync-motor's rotor. Consecutive winding phases (u,v,w) are switched such that the two switching signals (S1-S6) for the switches (TT-T6) of the phases being switched overlap in time. At least one of the two switching signals in the overlap region is timed so that the average of the current (Iu etc) in the phase being switched in increases whilst in the phase being switched out it decreases. A reference is defined for the phase currents (Iu etc.) ADVANTAGE - Reduced switching loses. Less noise. Radio-frequency interference is less.