capacitor instead of an electrolytic type. Moreover, capacitor-less inverter-based apparatus reduces EMC emission due to the limited voltage applied during switching. Clearly, changes and variations may be made to the inverter-based apparatus and to the controlling method without, however, departing from the scope of the present invention. Figure 5 illustrates a second embodiment of an inverter-based apparatus la, which is similar to the inverter-based apparatus 1 shown in Figure 3 and the component parts of which will be designated, where possible, by the same reference numbers as those that designates corresponding parts of the inverter-based apparatus 1. With reference to Figure 5, the inverter-based apparatus l a differs from the inverter- based apparatus 1 shown in Figure 3 because: the current regulator system 14 of the motor controller stage 6 is replaced with a sensor-less torque/flux regulator system 114, and the active voltage limiter unit 15 is replaced with an active voltage limiter unit 115, which cooperates with the sensor-less torque/flux regulator system 114 in order to regulate the torque reference Tref used by the sensor-less torque/flux regulator system 114 itself to control the switching units of the inverter 5, as hereinafter disclosed in detail. Furthermore, the inverter-based apparatus l a differs from the inverter-based apparatus 1 shown in Figure 3 because it comprises a voltage direct-Clarke convert stage 127 and a comparator 129, which will be hereinafter disclosed in detail. According to the second embodiment illustrated in Figure 5, the sensor-less torque/flux regulator system 114 is configured to receive in input information on the three-phase sensed currents iu(t), iv(t), iw(t). Moreover, the sensor-less torque/flux regulator system 114 is configured to receive in input information on signals Uu(t), Uv(t), Uw(t) above disclosed in detail for the first embodiment illustrated in Figure 3, and receive information on the sensed voltage Vdc(t) provided by the voltage sensor 13.