PHASE CONTROL CIRCUIT FOR CONTROLLED RECTIFIER

摘要

PURPOSE:To enable to standardize a rectifier without necessity of a phase shift transformer by obtaining a power source synchronizing signal for correcting the phase difference between a main circuit power source and a control power source. CONSTITUTION:A current flows to a photocoupler 18U during the positive half period of a voltage between lines of a control power source 8, and ''1'' logic value of control power source synchronizing signal 19U is obtained at the output. A power source synchronizing signal 12U of logic value ''1'' delayed by the prescribed time determined by the value of a phase difference signal 16 is generated at the output of a delay circuit 20U by the signal 19U. A phase control circuit 13A collects as a reference phase the rising time of the logic value from ''0'' to ''1'' of the signal 12U, outputs a gate signal 21 in response to a phase control signal 14 and controls the controlled rectifier element U of a rectifier 4.