A method for interconnecting electronic power modules of a polyphase rotary electric machine. The power modules are disposed in open cavities of a heat sink and comprise substrates on which are provided MOSFETs of a synchronous rectifier bridge and integrated control circuits. The method comprises the production of: a planar connector (6) including at least one layer of conductive traces (64); a plurality of interconnection elements (512) arranged in multiple geometric formations and ultrasonically welded or brazed (S2) directly to the substrates (51) and/or the MOSFETs; and openings (65) in the planar connector (6) allowing the free passage of the upper ends (5120) of the connection elements (512) and a mechanical contact with the conductive traces (64). The electrical connections are obtained by means of laser (8) transmission welding (S1) or electric resistance welding.