| 摘要 |
PURPOSE:To eliminate application of overvoltage and overcurrent due to commutation failure to a switching element by commonly connecting the secondary sides of transformers corresponding to respective inverter circuits and providing overvoltage protector at the DC side of the inverter circuit. CONSTITUTION:A series circuit of communication induction failure preventive reactor L1 and capacitors C1, C2 due to high harmonic wave is connected through a high velocity breaker HB to a DC power supply ED, and inverter units IV1, IV2 are provided in parallel with the capacitors C1, C2. The inverter units IV1, IV2 include respectively switching elements SU1-SZ1, SU2-SZ2, the inverter units IV1, IV2 are connected in seires, respective AC outputs are synthesized through transformers T1, T2 to obtain 12-phase AC outputs V0. Further, overvoltage protectors OVD1, OVD2 operating independently are provided in parapllel with the capacitors C1, C2. In this manner the elements can be exactly protected even at commutation failure time. |
