| 摘要 |
PURPOSE:To control occurrence of lower order higher harmonic component accompanied with an increase of thyristor phase angle by connecting series connected bilateral thyristor and reactor to a transfomer with a star connected primary winding and ring-and star connected secondary windings. CONSTITUTION:The power controlling device 40 has a transfomer with a star connected primary winding 41 and ring-and star connected windings 42, 43, to both secondary windings bilateral thyristors 53U to 53W and 54U to 54W and reactor 61U to 61W and 62U to 62W are connected. To the primary winding 41 of the transformer a phase advance capacitor 70 is connected in parallel. The higher harmonic components except 12n+ or -1 order becomes zero independent of values of phase angle to improve waveform distortion whereby filter of the higher harmonic components can be removed by setting a winding ratio of secondary winding 42 to 43 and a ratio of applied voltage 1Vu11 to 1Vu21 to be equal. |
