A system and method is provided for controlling conversion of a received DC voltage (Vdc) into an AC inverter voltage. The method includes determining a reference Vpor (Vpor_REF) based on measured or estimated Vdc such that Vpor_REF is feasible at all values of Vdc for regulating a modulation index signal M_abc at a selectable frequency ω as a function of a measured or estimated voltage at the point of reference (Vpor), wherein M_abc is regulated by Vpor_REF to regulate the inverter hardware circuit to output the AC inverter voltage in order for Vpor to satisfy a requirement appropriate for the load.