| 摘要 |
PROBLEM TO BE SOLVED: To suppress the harmonic components of input potential to be generated at the time of power recovery by subjecting the gates of self-extinguishing elements in first and second converters to ON control in synchronism with the phase of AC power supply voltage. SOLUTION: An input transformer TF has insulated three-phase secondary and tertiary windings S, T which produce balanced three-phase voltages A, B. The line voltages outputted from the secondary and tertiary windings S, T have a phase difference of 30 deg.. First and second converters 1A, 1B are connected between the secondary and tertiary windings S, T and arm elements, comprising self-extinguishing elements TRU1-TRZ1 and TRU2-TRZ2, are connected in bridge. The gates of first and second converters 1A, 1B are subjected to ON control by the phase difference of power supply. Since the combined current of first and second inverters flows on the primary of transformer TF at the time of rotational operation, harmonic components of input current are suppressed. |
