| 摘要 |
PROBLEM TO BE SOLVED: To increase DC currents gradually at the time of start, and prevent the instantaneous overcurrent at start by providing an initial control amplifier which controls the voltage set value of a voltage controller to zero during stoppage of a device, and returns the voltage set value gradually to the level of set value together with the time at the time of start of the device. SOLUTION: An initial control amplifier 20 generates output to control the voltage set value Vdcset to zero in device stop condition. This active filter is equipped with a soft start function which returns the set value Vdcset to the level of set value gradually according to the passage of time when a start signal START is inputted. The soft start function is materialized by the constitution of controlling, by a limiter, the voltage set value Vdcset on DC side with, for example, the output of the initial control amplifier 20. Hereby, instantaneous large current at start is controlled and the stop of the device by overvoltage is avoided. |
