PHASE CONTROL CIRCUIT OF 3-PHASE CONTROL RECTIFIER

摘要

PURPOSE:To always stably control a rectifier without influence of an input power source frequency by judging the phase rotation in a D flip-flop with a rectangular wave formed by selecting two of 3-phase AC inputs and shaping the waveforms as a reference. CONSTITUTION:A rectangular wave output from the first waveform shaper 14 is applied through an amplifier 21 to the D input of a D flip-flop 22. The rectangular wave output from the second waveform shaper 15 is applied as a clock of the flip-flop 22 through an inverter 17 to a C input. The D flip-flop detects normal and reverse phase rotations, and outputs detection signals from output terminals Q, -Q as positive and negative direction detection signals. The phase rotating directions are judged on the basis of the detection signals.