Method for decreasing amplitude of undesired harmonics and electronic multistage device for decreasing undesired harmonics

摘要

The invention concerns multistage power switching electronic device for reducing undesirable harmonics amplitudes generated in said device, in particular in the form of beats, comprising at least an input filter (1), a rheostatic braking chopper (2) including at least two switches (Fr1, Fr2) and mutlilevel static converter (4) including at least four switches in series (T1, T2, T3, T4). The invention is characterised in that the oscillator (4) is directly attached to the chopper (2) providing a connection by their midpoint (X = X') and it comprises a variable random frequency pulse generator controlling the switches of said chopper (2).