Patent ID: 8638007

Claim:
A converter device for supplying an AC voltage and current by filtering pulses obtained on a modulated signal output from three substantially DC voltages available on a reference voltage line and on two voltage inputs of opposite signs, said device comprising two switching units connected between said reference voltage line and respectively one and the other of said inputs, each switching unit comprising first switching means connected between the input to which said switching unit is connected and a switching output of said switching unit to supply pulses having the same sign as that of the voltage available on said input by main turn-ons and turn-offs of said first switching means, said device comprising, for each switching unit, second switching means associated with said switching unit and connected between said switching unit and said modulated signal output, and first control means acting on said second switching means to establish turn-on of said second switching means when the sign of said AC voltage is the same as that of the voltage on the input to which said switching unit is connected, wherein, for each switching unit, said device comprises a switching aid circuit of said switching unit connected between the input to which said switching unit is connected and the switching output of said switching unit to establish a switching voltage of said first switching means that is substantially equal to zero, before any main turn-on of the first switching means of said switching unit, for each switching unit said device comprises second control means acting on the second switching means associated with the switching unit that is connected to the voltage input of the same sign as that of said AC voltage to establish turn-off of said second switching means when said AC voltage and said AC current are of opposite signs, wherein each switching unit further comprises a diode connected between the reference voltage line and the switching output of said switching unit to establish a voltage equal to said reference voltage on said switching output when main turn-off takes place, wherein the switching aid circuit of each switching unit comprises inductive means, branch-off means for shunting a current from the switching output to divert said current to said inductive means before main turn-on, and energy storage means connected in parallel on the diode of said switching unit to establish a resonance of a current in said inductive means before main turn-on, and wherein the inductive means of the switching aid circuit of each switching unit consist essentially of a transformer connected to the switching output of said switching unit and comprising reverse-wound windings, and said branch-off means comprise auxiliary switching means directly connected between said inductive means and the voltage input to which said switching unit is connected.