| 摘要 |
Voltage control circuits (13, 23) are respectively provided for each rectifier (11, 21), for the control of the DC voltage, so that this corresponds with a voltage command value; also command value prodn. circuits (14a, 24a), each of which is provided for working in conjunction with each rectifier. The correction of the voltage command value is achieved by a signal, which is obtained by the amplification of the busbar current detected by a current detector (15, 25), using an amplifier which has a low frequency range limiting characteristic. The command value prodn. unit contains a limiter circuit, which limits a negative polarity of amplifier to zero, whilst allowing the output of a positive polarity or vice versa. |
