to implement the method to control the sensor-less torque/flux regulator system 114 in order to limit the voltage Vdc(t) of the DC-link capacitor 11 during a regeneration mode within a predetermined voltage range. In this respect, the control method implemented by the active voltage limiter unit 115 uses the estimated active current ia(t) and the maximum allowable regeneration current ialstAbs(t) to calculate the limit torque Tref_limit which is provided as torque reference Tref to the sensor-less torque/flux regulator system 114 when the target torque Tt is greater than the limit torque Trefjimit. Firstly, the control method performs the step of determining the active current ia(t) based on the equation l2b) ia(t) = Ia(t)*Ua(t)+ ( ί )* ( ί ) (block 500) Furthermore, the control method calculates the instantaneous maximum allowable regeneration current ialstAbs(t) (block 510) based on the measured voltage level and the prefixed parameter IaMaxAbs corresponding to the maximum absolute active current ia(t) for regeneration, iaIstAbs(t)=COv(t)IaMaxAbs Furthermore the control method calculates the value Ai (block 520) indicative of the difference bewteen the active current ia(t) and the maximum allowable regeneration current ialstAbs(t): Furthermore, the control method calculates the torque limit Tref_lim by the proportional-integral regulator H5a on the basis of value Ai (block 530). Furthermore, the control method controls whether the motor speed is positive (block 540). Ai= ia(t) - ialstAbs(t) When the motor speed is positive (co>0) (Output YES block 540) and the torque