motor (2) and comprises: - an input stage (4) which is connected to mains lines (8) for receiving AC lines currents and AC mains voltage and configured to convert said alternating mains voltage AC to a rectified DC voltage, - an electrolytic capacitor-less inverter (5) configured to generate output currents to be fed to said electric motor (2) based on duty cycles of switching signals, - a DC-link (10) which connects said electrolytic capacitor-less inverter (5) to said input stage (4) and is crossed by DC-link currents from, or towards, said electrolytic capacitor-less inverter (5), - a DC-link capacitor (11) connected to said DC-link (10), - a regulator system (14)(1 14) which is configured to control the duty cycles of switching signals based on at least a determined/estimated motor value (Id,Iq),(T) indicative of a controlled parameter of said electric motor (2), and at least a motor reference value (Idref,Iqref),(Tref), which is associated to said controlled parameter of said electric motor (2), the method being characterized by regulating said motor reference value (Idref,Iqref),(Tref) in order to limit the DC-link capacitor voltage (Vdc(t)) within a predetermined voltage range. 23. Method according to claim 22, wherein said determined/estimated motor values correspond to said output currents (iu, iv, iw), said motor reference values correspond to said current references (idref, iqref), said method comprises: - determining the amplitude of said DC-link capacitor voltage (Vdc(t)), - determining the amplitude of output currents (iu, iv, iw) provided to said electric motor (2) by said electrolytic capacitor-less inverter (5), - said regulator system (14) being configured to control said duty cycles of the switching units of said electrolytic capacitor-less inverter (5) based on said output currents (iu, iv, iw) and said current references (idref, iqref),