| 摘要 |
PURPOSE:To eliminate an increase in loss and deterioration by so controlling that a switching element which outputs an arc signal at the last of opening time and a switching element which outputs an arc signal at the initial of closing time always become different elements. CONSTITUTION:A controller of a power factor improving device is composed of a synchronous power source 12, a waveform shaper 13, 90 deg. and 270 deg. detectors 14-15, a power factor decrease detector 17, etc. In this case, two flip-flops(FF) 22, 23 having different input clock signals are provided, the FF 22 is operated at the timing of the output pulse from only the detector 14, and the FF 23 is operated at the timing of the output pulse from both the detectors 14, 15. Thus, it is output to a first thyristor of a pair of thyristors 8. Then, when the switch 8 is opened, a capacitor current becomes zero, its voltage becomes a bias to be applied to the first thyristor as a forward voltage and to the second thyristor as a reverse voltage. |
