POWER CIRCUITS FOR OBTAINING A HIGH POWER FACTOR ELECTRONICALLY

摘要

POWER CIRCUITS FOR OBTAINING A HIGH POWER FACTOR ELECTRONICALLY Solid state chopper circuits for alternatingcurrent or direct-current loads use only high frequency filtering and electronically shape the line current to obtain a high power factor. The control circuit generates a reference signal which is shaped according to a selected control function and also determines the input power. By comparing a sensed instantaneous power current with the reference signal, as by using a comparator with hysteresis, a solid state switch in the chopper circuit is operated at a high frequency chopping rate to shape the power current and therefore the line current. An application is a ballast for a gaseous discharge lamp. The preferred circuit is a signal phase transistor or gate turn-off thyristor d-c chopper fed by rectified unfiltered line voltage with a force load current waveshape for high power factor and good regulation.