Device for protecting against an electrical overcurrent in at least one electronic switching branch, conversion system including such a protection device, and associated control method

This device protects at least one electronic switching branch of an electrical conversion system against an overcurrent, each branch comprising two switching half-branches serially connected at an intermediate terminal, at least one half-branch including a switching member, each switching member comprising a first controllable switch and a diode connected in antiparallel to the first switch. The protection device includes, for each switching branch, at least one second controllable switch, each second switch being connected to the intermediate terminal or to an electrode of said diode in antiparallel to the first switch, each second switch being able to switch, under action of a controller, from an on state to an off state to protect said diode from the overcurrent, means for measuring a magnitude relative to a current able to circulate in each diode, and means for controlling each second switch, based on the measured magnitude.