Voltage lowering device and asynchronous traction system supplied from a single-phase mains supply incorporating a device of this kind

A voltage lowering device for producing a single intermediate direct current voltage, comprising:

• at least one pair of forced commutation single-phase rectifiers connected to secondary windings of a main traction transformer, said pair including a first forced commutation single-phase rectifier and a second forced commutation single-phase rectifier, said first forced commutation single-phase rectifier being connected to a first one of said secondary windings of said main traction transformer and said second forced commutation single-phase rectifier being connected to a second one of said secondary windings of said main traction transformer, wherein power drawn from a direct current main power supply passes through said main traction transformer and is recovered at said first one of said secondary windings by means of said first forced commutation single-phase rectifier operating as a voltage increasing controlled rectifier, said second forced commutation single-phase rectifier operating as a synchronous voltage inverter, wherein a primary winding of said main transformer is an open circuit.