Energy transfer concept in AC/DC switch mode power supply with power factor correction
AssigneeUniversity of Central Florida
InventorsIssa Batarseh, Wenkai Wu, Weihong Qiu, Wei Gu
Life of this patent
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Abstract
A new innovative concept in AC/DC cell that transfers energy to the output side directly from the input line, rather than from the storage capacitor in power factor correction (PFC) cell during the period that the line voltage exceeds a preset value. The new concept is based on providing additional winding coupled to the DC/DC transformer connected to the rectified input side to provide a path for the energy transfer from the line to transfer to the output directly (Boost cell) or to be stored in the output transformer (Flyback cell).
Claims20
A power-factor-correction (PFC) switching power supply apparatus that converts AC to DC and operates over a range of output currents comprising:
- (a) a power-factor-correction (PFC) cell having an alternating current input and a direct current output;
- (b) a direct current to direct current (DC/DC) cell having both a direct current input coupled to the direct current output of said power factor cell and to a direct current output;
- and,
- (c) means for transferring the direct current output of said rectified line power directly to the output side of the DC/DC cell when the line voltage exceeds a preset value whereby an operating mode is realized that provides higher overall efficiency with higher power factor and lower current harmonics of the AC to DC converted output currents.
A method for operating a power-factor-correction switching power supply that converts AC to DC and operates over a range of output currents, comprising the steps of:
- (a) introducing an alternating current into a rectifier and then into a power-factor-correction (PFC) cell having a direct current output;
- (b) coupling the current output of said power factor cell to a direct current output of a direct current (DC/DC) cell;
- (c) coupling an output of the rectifier to the direct current input of said (DC/DC) cell;
- and,
- (d) sensing rectified line voltage variations for transferring the direct current output of said rectified line power directly to the output side of the DC/DC cell when the AC line voltage exceeds a preset value whereby an operating mode is realized that provides higher overall efficiency with higher power factor and lower current harmonics of the AC to DC converted output currents.
The method of providing a preset voltage value for transfer of energy from the rectified output of a PFC cell—DC/DC cell power supply by a transformer having secondary and primary windings directly to the input of the DC/DC cell comprising:
- (a) means for determining when the AC line voltage exceeds a value which provokes said rectified value in excess of the present voltage;
- (b) means for measuring the number of secondary windings of the transformer connected to said rectified output through a diode which passes said energy;
- and
- (c) means for measuring the number of primary windings used for transfer of energy to the input of said DC/DC cell whereby the preset value is obtained.
Dependencies are inferred from the claim text.