| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a DC voltage step-down circuit and an electric power conversion system that eliminates the need for the balance resistance of electrolytic capacitor that is connected in series. <P>SOLUTION: A DC voltage step-down circuit has, in parallel with an input DC power supply 1, a capacitor series assembly 4 consisting of electrolytic capacitors 2, 3 connected in series, and includes a switching device series assembly 7, consisting of switching devices 5,6 in series connected in parallel with the input DC power supply 1; a single phase full-wave diode bridge 10, in which an intermediate connecting point 8 of the capacitor series assembly 4 and one end of AC input terminal are connected, and an intermediate connecting point 9 of the switching device series assembly 7 and the other end of AC input terminal are connected; an electrolytic capacitor 11 connected between DC output terminals of the single phase full-wave diode bridge 10; and a drive control circuit 12 for controlling so as to complementarily drive the switching devices 5, 6. <P>COPYRIGHT: (C)2007,JPO&INPIT |
