of the switching unit of the inverter 5. The direct-Clarke convert stage 126 is configured to convert the three-phase sensed currents iu(t), iv(t), iw(t), to a two-phase , Park-coordinate system (stationary reference frame), and outputs current values ia(t) and ( ί ). With reference to the second embodiment illustrated in Figure 5, the active voltage limiter unit 115 is configured to receive in inputs: current signals ia(t), current signal ( ί ), the signal Ua(t) in the two-phase , Park-coordinate system, the signal ( ί ) in the two-phase , Park-coordinate system, and the voltage Vdc(t) of the DC-link capacitor 11. The active voltage limiter unit 115 is configured to provide a torque limit Trefj signal based on the current signal ia(t), the current signal ( ί ), the voltage signal Ua(t), the voltage signal ( ί ), and the voltage Vdc(t), by implementing the method hereinafter disclosed. Preferably, the active voltage limiter unit 115 is configured to regulate the torque reference Tref based on the torque limit Trefjim in order to limit the DC-link capacitor voltage Vdc(t) within a predetermined voltage range. According to a preferred embodiment illustrated in Figure 5, the active voltage limiter unit 115 is configured to calculate the active current ia(t) by performing the equation l2b): ia(t) = ia(t)*Ua(t)+ ( ί )* ( ί ) Furthermore, the active voltage limiter unit 115 is configured to calculate the instantaneous maximum allowable regeneration current ialstAbs(t) according to the equation (15). More specifically the maximum allowable regeneration current ialstAbs(t) is calculated based on the measured voltage level and the prefixed parameter iaMaxAbs corresponding to a maximum absolute active current ia(t) for regeneration wherein c V is a weight coefficient that depends on the voltage Vdc(t) and a nominal iaIstAbs(t)=coV*IaMaxAbs