INVERTER TRANSFORMER Russian patent published in 2002 - IPC

FIELD: converter engineering; ac drives. SUBSTANCE: inverter transformer has b three-phase primary windings and composite magnetic circuit that incorporates external core stacked of electric steel stampings whose slots accommodate primary windings placed therein in specified manner and coaxial internal core stacked of same steel stampings whose slots accommodate three-phase secondary winding turns; internal core is of precision armature winding type shortened to specified length according to specified law of turn number distribution in coils of coil groups. When three-phase primary windings are energized, they pass currents building up revolving magnetic field in composite magnetic circuit; main magnetic flux due to this field crosses secondary winding turns and induces electromotive force of desired magnitude ; unwanted higher harmonics are filtered off in this case due to specific design of winding, therefore output voltage of inverter transformer will be of quasi-sinusoidal waveform. EFFECT: reduced mass, space requirement, and power loss. 2 dwg