| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the distortion of the current waveform of a 3-phase AC input. SOLUTION: When a power transistor 1 (2 or 3) in an AC-DC conversion circuit 22 (23 or 24) provided between an R-phase and an S-phase (an S-phase and a T-phase or a T-phase and an R-phase) is in an ON-state, a feedback current which flows from the S-phase (the T-phase or R-phase) of a 3-phase AC power supply to the T-phase (the R-phase or the S-phase) of the 3-phase AC power supply through a step-up reactor 7 (8 or 9), the power transistor 1 (2 or 3) and the rectifying diode 29b (27b or 28b) of a rectifying bridge circuit 29 (27 or 28) in the AC-DC conversion circuit 24 (22 or 23) provided between the T-phase and the R-phase (the R-phase and the S-phase or the S-phase and the T-phase) is blocked by a feedback current blocking diode 48 (49 or 50) connected in the AC-DC conversion circuit 22 (23 or 24). With this constitution, the waveforms of the respective line currents of the 3-phase AC power supply can be sinusoidal and the distortion of the current waveform of the 3-phase AC input can be eliminated. |
