Patent ID: 6061256
Filing Date: 2000-05-09
Classification: H02M,Y02B

Abstract:
An apparatus for conversion of a three-phase voltage system into an electrically isolated DC voltage to be predetermined freely, the apparatus comprising:a primary circuit having phases, a positive primary voltage rail and a negative primary voltage rail;each of said phases of said primary circuit having an associated bidirectional, bipolar electronic switching apparatus with first and second inputs, a series inductance connected to said first input, a first diode feeding said positive primary voltage rail, and a second diode feeding said negative primary voltage rail;a transformer having a primary winding with first and second winding end terminals, and a secondary winding;a line connected between said first winding end terminal and said second inputs of said switching apparatuses;a first power transistor connected to said second winding terminal of said primary winding and having a collector or drain side connected to said positive primary voltage rail, and a diode connected antiparallel to said first power transistor;a second power transistor connected to said second winding terminal of said primary winding and having an emitter or source side connected to said negative primary voltage rail, and a diode connected antiparallel to said second power transistor; anda secondary circuit having a single-phase diode bridge with input terminals connected to said secondary winding of said transformer, and output terminals, and a capacitance connected between said output terminals for smoothing an output voltage as a full-wave bridge circuit.