DIRECT FREQUENCY CONVERTER Russian patent published in 2002 - IPC

FIELD: semiconductor converters for direct transformerless three-phase voltage conversion. SUBSTANCE: newly introduced in classic transformerless frequency- conversion circuit that may be used in AC drive systems or in AC power generating systems are n output filter chokes 4 and two n-phase rectifier bridge circuits built around diodes 7 and 9 with unidirectional switches 8 and 10 in each circuit; inputs of first n-phase rectifier bridge circuit are connected to points of connection of storage chokes and storage capacitors; inputs of second n-phase rectifier bridge circuit are connected to points of connection of second leads of storage capacitors and to output filter chokes; unidirectional switches are connected in each circuit to output of respective n-phase rectifier bridge circuit; storage chokes are connected to each common point of input-switch star connection, and load is connected to common point of connection of output filter choke and output filter capacitor. Converter input circuit continuously carries current, that is, its waveform is improved due to absence of no-current intervals. EFFECT: improved harmonic content of input current curve, enhanced input power factor. 2 dwg