said method regulates said current references (idref, iqref) of said regulator system (14) in order to cause said DC-link capacitor voltage (Vdc(t)) to be limited within said predetermined voltage range. 24. Method according to claim 23, comprising the step of regulating said current references (idref, iqref) of said regulator system (14) in order to cause said DC-link capacitor voltage (Vdc(t)) to be limited within said predetermined voltage range, without using said lines currents and/or DC-link currents. 25. Method according to claims 23 or 24, comprising the step of clamping said DC-link capacitor voltage (Vdc(t)) to a prefixed value, when said electric motor (2) regenerates back current to said the DC-link capacitor (11) via said electrolytic capacitor-less inverter (5). 26. Method according to any of the foregoing claims from 23 to 25, comprising: determining an active current (ia)(iaref) based on said output currents (iu, iv, iw) and said duty cycles; regulating said current references (idref, iqref) based on said active current (ia)(iaref) and said DC-link capacitor voltage (Vdc(t)). 27. Method according to claim 26, comprising the step of wherein said active determining a first active current (ia) based on the d-q axis-wise duty cycles (Ud, Uq) which are indicative of said duty cycles of the switching signals and d-q axis-wise currents (id, iq) indicative of said output currents (iu, iv, iw). 28. Method according to claims 26 or 27, comprising the step of determining a second active current (iaref) based on the d-q axis-wise duty cycles (Ud, Uq) indicative of said duty cycles of the switching signals and said determined current references (idref, iqref).