| 摘要 |
PURPOSE:To make the operation over the broad frequency range possible by connecting two sets of power rectifiers, DC reactors and inverters in parallel and controlling the apparatus so as to coincide the commutation timing of both inverters. CONSTITUTION:Two sets of power rectifiers 2, reactors 3 and inverters 4 are connected in parallel. Depending on the operating conditions of an AC motor 5, two sets are used or only one set is used by switching. When the gate signal of the thyristor of each inverter 4 is applied at the same time, the individual commutation capacitors are connected in parallel, and the commutation capacitors are provided with the same effect as the increase in capacity. In this constitution, if a capacitor voltage becomes too large, parallel operation is employed; and if the output frequency is high, single operation is employed; thereby the optimum capacitor is selected and the operation is carried out. |
