| 摘要 |
PURPOSE:To eliminate the need of large and expensive resistors, switches, and the like by performing the phase control of current such that an undue charging current does not flow at the initial charging stage of a capacitor having high capacitance and performing the current control such that an undue discharge current does not flow at the time of perfect discharge clue to stoppage of operation. CONSTITUTION:An initial charge control circuit 10 for a capacitor C1 receives an AC power supply voltage V1, a signal V1z representative of the zero-cross point thereof, and a voltage Vdc between DC buses P, N and delivers drive signals S111, S121 individually to the thyristors THYs 11, 12 in a switch SW1 based on an initial charging command IC. An initial charge control circuit 20 delivers drive signals S211, S221 for the thyristors THYs 21, 22 in a switch SW2. Furthermore, a perfect discharge control circuit 30 delivers a drive signal to the thyristors THYs 11, 12 in order to control perfect discharge of the capacitor C1. |
