| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a DC power supply unit having high efficiency, able to prevent scale-up of the unit as a whole, and can be readily changed for the specifications having different output voltage or output current. <P>SOLUTION: The DC power supply unit which receives an input of three-phase AC from a commercial power supply 11 and obtains a DC output 17 from the three-phase AC includes, arranged in the order, i.e. a single-phase rectifier 12, which applies full-wave rectification to an interphase voltage between phases of the three-phase AC; a power-factor improving circuit 13 for single-phase which steps up the full-wave rectified interphase voltage, to obtain DC power for driving an inverter, and controls so that an input current waveform becomes a similar figure of an input voltage waveform; an inverter circuit 14, which applies pulse-width modulation to a DC voltage from the power-factor improving circuit 13 for single-phase, to obtain a high-frequency voltage; a transformer 15, which accepts the high-frequency voltage applied thereto and converts the high-frequency voltage into a predetermined voltage; and a rectification smoothing circuit 16, which rectifies and smoothes the high-frequency voltage converted into the predetermined voltage in the transformer 15 to obtain the DC output 17. In the power supply unit, the output terminals of phases from the rectification smoothing circuit 16 are each connected in series. <P>COPYRIGHT: (C)2011,JPO&INPIT |
