THREE-PHASE AC-TO-DC VOLTAGE CONVERTER Russian patent published in 1994 - IPC

FIELD: converter engineering. SUBSTANCE: converter has transformer 1 with three-legged core 2. One core leg, say extreme one, carries primary phase winding 3 connected to phase supply voltage U_A (terminals A-O). Other core leg, say intermediate one, carries primary phase winding 4 connected to line supply voltage U_BC (terminals B-C of supply mains). Same legs carry secondary windings 5 and 6, winding 5 having root of 3 times smaller number of turns than winding 6. Each of windings 5 and 6 has center tap both connected to O point. Vacant terminals a and x of winding 5 are connected to gate elements of voltage rectifying unit, for example, to diodes 7 and 8. Vacant terminals b and c of winding 6 are connected to diodes 9 and 10. Load 11 is connected between common point of cathodes (or anodes) of diodes 7-10 and common neutral point O of both stars. Core may be made as four-leg structure (shell-type). EFFECT: improved ripple frequency ratio of output voltage, as high as up to 4, while forced magnetizing flux is eliminated. 3 dwg