FIELD: converter engineering; independent voltage and frequency control of multiphase load such as induction-motor stator winding. SUBSTANCE: inverter has its voltage and frequency setting elements; logic device; power switches unit; multiphase generator whose input functions also as output of inverter frequency setting element and its nine outputs are connected to first nine inputs of logic device; reference-voltage generator; inverting amplifier whose input is output of inverter voltage setting element; two comparators whose first inputs are connected, respectively, to output of voltage setting element and to that of inverting amplifier, its second inputs being interconnected and connected to reference-voltage generator output and its outputs, to tenth and eleventh inputs of logic device; three outputs of the latter function as inputs of dead zone shaper; six outputs of the latter are connected to six control inputs of load power switches unit. Novelty is introduction of third, fourth, fifth, and sixth comparators whose first inputs are connected to output of reference-voltage generator and outputs, to additional inputs of logic device; two scaling amplifiers with gain factors of 0.732 and 0.268 whose inputs are connected to output of inverter voltage setting element and outputs, to second inputs of third and fifth comparators, and to newly introduced second and third inverting amplifiers, respectively, outputs of these amplifiers being connected to second inputs of fourth and sixth comparators, respectively. EFFECT: improved output characteristics of inverter (essentially reduced higher-harmonic content of its output voltage). 10 dwg
