METHOD FOR DIAGNOSTICS OF A THREE-PHASED THYRISTOR RECTIFIER Russian patent published in 2007 - IPC G01R31/02 

FIELD: power electronics, in particular, methods for diagnostics of three-phased thyristor rectifiers.

SUBSTANCE: in accordance to the invention, curves of instant values of phase currents of rectifier, incoming from current sensors, are registered. Positive directions of phase currents are set, which are directed from points of connection of two shoulders of bridge branches to an average point of secondary winding of powering transformer. Correspondence of given direction and real directions is determined. Coincidence with real directions corresponds to positive values of semi-period current and conductivity of thyristors of anodic group, non-coincidence corresponds to negative values of semi-period current and conductivity of thyristors of cathode group. First harmonics of phase currents are compared to each other. On basis of least amplitude of first current harmonic in one of phases, a branch with a defect is detected. On basis of shape of phase current curve, certain defective bridge shoulder is detected. To determine control angle of each thyristor, curve of instant voltage values, incoming from voltage sensor, installed in output circuit of rectifier, is additionally registered. Joint analysis of curves of instant values of phase currents of output voltage is performed and linear voltages are determined for each section of output voltage curve. Control angle is determined for each thyristor. On basis of difference between control angles and a given value, asymmetry of thyristor control angles is determined.

EFFECT: detection of a branch with a defect, determined certain defective shoulder of a bridge for with any number of defective shoulders and determined asymmetry of thyristor control angles.

2 cl, 9 dwg