| 摘要 |
PURPOSE:To protect an inverter against the defect of a partial unit inverter by providing a protecting circuit for enhancing impedance which is observed in the interior of the inverter at each group of unit inverters of from its DC terminal. CONSTITUTION:High speed interrupters 301, 302 are provided at the input sides of unit inverters 201, 202. The interrupters 301, 302 are closed in the normal operation, but closed by a signal from a defect detector when the unit inverter is defective or an interrupting mechanisms of the interrupters 301, 302. When a commutation failure occurs in the unit inverter 202, the interrupter 202 is immediately opened. Subsequently, when all GTOs of the inverter 202 are turned OFF and observed in the interior of the inverter from the AC terminal of the inverter 202, the internal impedance may become maximum. Simultaneously, the pulse width of the inverter 201 is controlled, thereby approaching the voltage of the AC output bus 22 to the voltage and phase of a load or the like. |
