| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit capable of converting AC power to DC power without having a rectification circuit or a smoothing circuit in a primary circuit.SOLUTION: A power supply circuit for converting input three-phase AC to DC and outputting the current includes: a transformer; an input phase switch part; a rectification part; and a smoothing part. The transformer has a primary coil and a secondary coil. The input phase switch part switches the input voltage to the primary coil so that the largest phase voltage is input to one terminal of the primary coil in a first switching period shorter than the cycle of the input three-phase AC, and that the smallest phase voltage is input to one terminal and the largest phase voltage to the other terminal in a second switching period continued from the first switching period and shorter than the cycle. The rectification part is connected to the secondary coil to rectify the output voltage of the secondary coil. The smoothing part is connected to the rectification part to smooth the output voltage of the secondary coil and output the voltage to an output terminal. |
