JPS54129426A - Rectifier - Google Patents

Abstract

PURPOSE: To reduce equivalent interference current by simultaneously phase controlling output currents in two windings of different output voltages of one or more single-phase transformers for each transformer with a control circuit such that the output current from a rectifying circuit for phase control and rectification is constant.

CONSTITUTION: The U1-V1 voltage across the secondary winding of a transformer T is set, for instance, to be 10% lower than the U2-V2, and a phase angle α2 is set for an instant, at which the U2-V2 voltage of the secondary winding becomes equal to the U1-V1 voltage. At the time of the acceleration, the DC current is detected with current detectors CD1 and CD2, and a signal given to the gates of the thyristors in bridges B1 and B2 is controlled with a control system such that the detected current is constant. In this way, it is possible to balance the circuits of the bridges B1 and B2 both voltage-wise and current-wise and obtain gentle rising of the current waveform of the sum of AC currents in the bridges B1 and B2 as shown at (d) in the Figure with the phase angle relation made to be α1<α2 for reducing the power source side harmonic frequency components.

COPYRIGHT: (C)1979,JPO&Japio