Method for the piloted start-up of a gas turbine of an aircraft, and corresponding system

A method for starting a gas turbine of an aircraft, a starting system being configured to drive a shaft of said gas turbine in rotation, said starting system comprising a control system and an electric machine of the brushless asynchronous type and being powered by a DC voltage (Uin), said starting method comprising the steps of:

• receiving, by the control system, a first value (N), representative of a speed of rotation of a rotor of the electric machine;
• receiving, by the control system, a second value (Tin);
• converting, by the control system, the DC voltage (Uin) into a three-phase voltage system for controlling the electric machine;
• and
• controlling, by the control system, the electric machine using the three-phase control voltage system,
• wherein, the second value (Tin) is representative of a ratio of a determined target torque of the electric machine, adapted to drive the rotation of the rotor of the electric machine at a determined speed, to the theoretical maximum torque that the electric machine can produce at the determined speed of rotation of the rotor, and
• during the modulation, a frequency (Fs) and an amplitude (Vs) of the voltages of the three-phase control voltage system are determined according to a control law dependent on the second value (Tin).