POWER FACTOR CORRECTOR WITH HIGH POWER FACTOR AT LOW LOAD OR HIGH MAINS VOLTAGE CONDITIONS

摘要

A power factor corrector raises power factor at low loads or high mains voltages by modifying the switch timing or the current received by the power converter. It achieves this by increasing the switch -on time of a control switch during the falling time so that the majority of the switch -on time during a mains period occurs during the falling time, to thereby control the current received by the converter to compensate for current received by the intermediate filter. Some embodiments may employ a feedback system to produce one or more error signals that modify the control signal used to control the operation of the converter. Various embodiments may also include additional stages that limit the compensation range of the error signal.