Patent ID: 8488352

Claim:
A method for varying power factor applied to an alternating-current voltage apparatus, a bridge rectifier, a power factor correction unit, a switch unit, a control unit, and a rear end circuit; an alternating-current voltage being sent from the alternating-current voltage apparatus to the bridge rectifier; the alternating-current voltage being transformed into a rectified voltage by the bridge rectifier; the rectified voltage being sent from the bridge rectifier to the power factor correction unit; a first primitive conduction pulse being sent from the control unit to the switch unit to control the power factor correction unit to produce a first primitive current having the same phase of a first voltage of the rectified voltage; the first primitive current being sent from the power factor correction unit to the rear end circuit; a second primitive conduction pulse being sent from the control unit to the switch unit to control the power factor correction unit to produce a second primitive current having the same phase of a second voltage of the rectified voltage; the second primitive current being sent from the power factor correction unit to the rear end circuit; the method for varying power factor including: a. the control unit sending a first modified conduction pulse to the switch unit; b. the switch unit controlling the power factor correction unit to produce a first modified current after the first modified conduction pulse is received by the switch unit; c. the control unit sending a second modified conduction pulse to the switch unit; and d. the switch unit controlling the power factor correction unit to produce a second modified current after the second modified conduction pulse is received by the switch unit, wherein the value of the first modified current is different from the value of the first primitive current; the value of the second modified current is different from the value of the second primitive current.