(84) Designated States (unless otherwise indicated, for every kind of regional protection available) : ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM, TR), OAPI (BF, BJ, CF, CG, Cl, CM, GA, GN, GQ, GW, KM, ML, MR, NE, SN, TD, TG). — with international search report (Art. 21(3)) — before the expiration of the time limit for amending the claims and to be republished in the event of receipt of amendments (Rule 48.2(h)) Published: 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,Jqref)(Tref), which is associated to the controlled parameter of the electric motor (2), the inverter-based apparatus (l)(la) further comprises an active voltage limiter unit (15)(1 15), which is configured to regulate the motor reference value (Idref Jqref)(Tref) in order to limit the DC-link capacitor voltage (Vdc(t)) within a predetermined voltage range.