| 摘要 |
A control unit of a system stabilization device uses a fluctuation detection block (60) to determine fluctuation components included in the active component and reactive component currents of a system current and fluctuation components included in the frequency signal and the amplitude signal of a system voltage. The cut-off frequency on the high frequency side of the fluctuation detection block (60) is set to be f1; the cut-off frequency on the low frequency side is set to be f2; the time constant of the low-pass filter for noise removal which has a cut-off frequency of f1 is set to be T1; and the time constant of the low-pass filter for setting a fluctuation detection time which has a cut-off frequency of f2 is set to be T2. The fluctuation detection block (60) is composed of a low-pass filter (61) having first order lag characteristics with a time constant of T1, a low-pass filter (62) having first order lag characteristics with a time constant of T2, a subtracter (63) which performs subtraction between the output signals of the filter (61) and the filter (62) and outputs the difference, and a feedback circuit (64) which provides feedback on the output of the subtracter (63) to the filters (61, 62). Thus, stable actions are ensured without using a current detector or the like. |
