| 摘要 |
PURPOSE:To prevent the fluctuation of voltage over all the frequencies generating flickers by detecting dc of the system voltage through averaging the system voltage by means of a low-pass filter. CONSTITUTION:A low-speed AVR control circuit 14 averages the system voltage VL through a low-pass filter and a fluctuating component of the averaged signal is taken out as a low-band detection signal of a flicker V10. A high-speed DELTAV control circuit 13 turns the system voltage VL to dc by adding a +90 deg. shifted value of the squared value of the system voltage VL and a -900 deg. shifted value and a fluctuating component of the dc signal is taken out as a high band detection signal of the flicker V10. A phase control circuit 38 adds the output of the low-speed AVR control circuit 14 and that of the high-speed DELTAV control circuit 13 and thereby generates a phase control signal DELTAVc. By this method, the fluctuation of voltage can be prevented over all the frequencies of the flicker V10. |
