illustrated in Figures for the sake of clarity. The voltage sensor 13 is preferably configured to sense the voltage Vdc(t) of the DC-link capacitor 11. With reference to Figure 3, the motor controller stage 6 may comprise a current regulator system 14 and an active voltage limiter unit 15. The current regulator system 14 is configured to: receive information on the sensed currents iu(t) ,iv(t), iw(t) from the current sensor 12, receive information on the sensed voltage Vdc(t) from the voltage sensor 13, receive information on a motor control parameter, i.e. a requested motor speed Spdref provided by an electronic control unit 110 of the machine 100, and to generate three signals Uu(t), Uv(t), Uw(t) to control the switching units (not illustrated) of the inverter 5. The signals Uu(t), Uv(t), Uw(t) may be indicative of duty cycles of the command signals provided to the switching units of the inverter 5. The signals Uu(t), Uv(t), Uw(t) may be also per-unit signals indicative of the fraction of DC-link voltage to be applied to each phase of the motor. The three signals Uu(t), Uv(t), Uw(t) may be pulse width modulation signals (PWM). According to an embodiment shown in Figure 3, the current regulator system 14 may comprise: an subtractor stage 20, a speed control stage 21, a flux weakening stage 22, a currents regulator stage 23, an inverse-Park transform stage 24, an inverse- Clarke convert stage 25, a direct-Clarke convert stage 26, a direct-Park transform stage 27, and a sensor-less speed/flux position observer stage 28. The direct-Clarke convert stage 26 is configured to convert the three-phase sensed currents iu(t), iv(t), iw(t) into a two-phase , Park-coordinate system (stationary reference frame), and provide current values ia(t) and ( ί ) to the direct- Park transform stage 27 and to the sensor-less speed/flux position observer stage 28. The sensor-less speed/flux position observer stage 28 is configured to receive two current values ia(t) and ( ί ) and two signals Ua(t) and ( ί ). The signals Ua(t) and ( ί ) are indicative of two duty cycles values in the two-phase , Park-coordinate system. The sensor-less speed/flux position observer stage 28 is further configured to