Power supply apparatus

摘要

A high-efficiency power supply apparatus is provided in light of the reduction of the switching loss. The power supply apparatus connected between the AC power supply and the DC load converts the AC power supplied from the AC power supply to the DC power and supplies it to the DC load. The power supply apparatus comprises the first switching circuit for outputting the switched positive and negative voltages to the primary winding of the transformer, a second switching circuit for supplying the DC power induced in the secondary winding of the transformer and switched to the DC load connected to the second AC terminals, a resonance inductor serial-connected to the primary winding, and a control unit for controlling the switching operations performed by the first and second switching circuits. The control unit substantially short-circuits the second AC terminals by controlling the switching operations performed by the second switching circuit.

主权项

1. A power supply apparatus connected between an AC power supply for supplying AC power and a DC load, for converting the AC power supplied from the AC power supply to DC power and supplying to the DC load, comprising:
a first switching circuit for
inputting a full-wave-rectification voltage of the AC power supply, by way of a first DC terminal; andoutputting positive and negative voltages generated by performing switching operations to the input voltage to a primary winding of a transformer connected to first AC terminals; a first smoothing capacitor connected to the first DC terminals; a second switching circuit for
inputting electric power induced in a secondary winding which is magnetic-coupled to the primary winding and configures the transformer by way of a second AC terminal connected between terminals of the secondary winding; andsupplying the DC power generated by performing switching operations to the input electric power and smoothed by a second smoothing capacitor connected to second DC terminals, to the DC load connected to the second DC terminals; a resonance inductor serial-connected to either of the primary winding or the secondary winding, or both thereof; and a control unit for controlling the switching operations performed by the first and second switching circuits, respectively, wherein the first switching circuit comprises a first switching leg to serial-connect first and second switching elements and a second switching leg to serial-connect third and fourth switching elements; the first and second switching legs are mutually parallel-connected; terminals of the first switching leg comprise the first DC terminals; terminals connected to a serial node of the first and second switching elements and a serial node of the third and fourth switching elements comprise the first AC terminals; the second switching circuit comprises a third switching leg to serial-connect a fifth diode and a fifth switching element and a fourth switching leg to serial-connect a seventh diode and a sixth switching element; the third and fourth switching legs are mutually parallel-connected; terminals connected to the third switching leg comprise the second DC terminals; terminals connected to a serial node of the fifth diode and the fifth switching element and a serial node of the seventh diode and the sixth switching element comprise the second AC terminals; the control unit is configured to adjust magnitude of the DC power supplied to the DC load, by alternatively switching and executing a first duty control for changing a duration of a period to apply the positive and negative voltages to the first AC terminals, or a second duty control for changing a duration of a period to substantially short-circuit the second AC terminals while applying the positive and negative voltages to the first AC terminals; the first duty control is a first phase-shift control for changing a phase of a turn-off timing of the first and fourth switching elements and a turn-off timing of the third and second switching elements; and the second duty control is a second phase-shift control for changing a phase of a turn-off timing of the first through fourth switching elements and a turn-off timing of the fifth and sixth switching elements.