Patent ID: 8294412

Claim:
A method of controlling a rotary electrical machine connected to an electrical system in the event of a load dump, the machine comprising: a plurality of phase windings ( 9 ); a power circuit ( 12 , 16 ) comprising a plurality of arms, each formed by a bridge of switches associated with one of the phase windings ( 9 ), the power circuit ( 12 , 16 ) provided for supplying the electrical system at an output voltage (Vres) equal to a nominal voltage (Vn) when the bridge of switches is in a nominal mode of operation; an excitation winding ( 11 ) through which flows an excitation current (I exc) producing a magnetic flux in a magnetic excitation circuit ( 10 ); and an electronic control and regulating circuit ( 7 ) operating the power circuit ( 12 , 16 ) and controlling the excitation current (I exc); the method comprises comprising the steps of: locking the bridge of switches in at least one of the arms of the said power circuit ( 12 , 16 ) in a conductive state when the output voltage (Vres) exceeds a predetermined voltage threshold (Vs) higher than the said nominal voltage (Vn); the nominal mode of operation of the bridge of switches is returned to independently of the said output voltage (Vres).