Drive chain able to be connected to an alternating electrical network and comprising: - an electric machine comprising a rotor and a stator, the stator being able to be connected electrically to an alternating network and having a stator frequency (f stator), - a bidirectional system for converting an alternating electrical current into another alternating electrical current, and able to be connected between the alternating network and the rotor of the electric machine, the bidirectional conversion system comprising: ∘ a bidirectional converter for converting an alternating current into a continuous current and able to be connected to the alternating network, ∘ a bidirectional inverter for converting a continuous current into an alternating current and connected between the AC/DC converter and the rotor, the DC/AC inverter comprising controllable electronic switches able to convert a DC voltage into an AC voltage, and a terminal for connection to the rotor for each phase of the AC voltage, and ∘ a device for controlling the switches of the DC/AC inverter according to a control law, characterised in that the control law is such that the active power exchanged by the DC/AC inverter with the rotor is less than 0.3 times the nominal power of the direct current able to circulate between the AC/DC converter and the DC/AC inverter, for the frequencies of a target interval of between 0.6 times the stator frequency (f stator) and 1.4 times the stator frequency (f stator), and such that said exchanged active power is greater than 0.3 times the nominal power, only during a transitory period of less than 30 ms following the occurrence of a fault on the alternating network. - an electric machine comprising a rotor and a stator, the stator being able to be connected electrically to an alternating network and having a stator frequency (f stator), - a bidirectional system for converting an alternating electrical current into another alternating electrical current, and able to be connected between the alternating network and the rotor of the electric machine, the bidirectional conversion system comprising: ∘ a bidirectional converter for converting an alternating current into a continuous current and able to be connected to the alternating network, ∘ a bidirectional inverter for converting a continuous current into an alternating current and connected between the AC/DC converter and the rotor, the DC/AC inverter comprising controllable electronic switches able to convert a DC voltage into an AC voltage, and a terminal for connection to the rotor for each phase of the AC voltage, and ∘ a device for controlling the switches of the DC/AC inverter according to a control law, ∘ a bidirectional converter for converting an alternating current into a continuous current and able to be connected to the alternating network, ∘ a bidirectional inverter for converting a continuous current into an alternating current and connected between the AC/DC converter and the rotor, the DC/AC inverter comprising controllable electronic switches able to convert a DC voltage into an AC voltage, and a terminal for connection to the rotor for each phase of the AC voltage, and ∘ a device for controlling the switches of the DC/AC inverter according to a control law,