HIGH-FREQUENCY DC-TO-AC VOLTAGE CHANGER INCORPORATING ELECTRONIC PROTECTIVE DEVICE Russian patent published in 2004 - IPC

FIELD: power conversion engineering; feeding electrical installations. SUBSTANCE: proposed voltage changer is built around off-line voltage inverter that has thyristors 1 - 4, opposing diodes 5 - 8, oscillatory switching circuit incorporating reactor 9 and capacitor 10, transformer 11, and control unit 12. Variable voltage component filter connected at inverter input has reactor 13, capacitor 14, and additional reactor 15; mentioned control unit has clock generator 16, scaling unit 17, control current pulse shaper 18, and electrical isolation device 19. In addition control unit has inhibit location with memory 20 and emergency current signal sensor 21. Such design of control system ensures that generation of control current pulses by inverter thyristors is ceased in 0.2 of inversion period and that emergency current pulse length is not over 0.25 of this period. EFFECT: reduced transient time in emergency disconnection of inverter; reduced maximum of short-circuit current. 1 cl, 3 dwg