| 摘要 |
PURPOSE:To prevent promotion of voltage rise in a DC bus, by keeping the voltage command immediately before switching of operating mode as it is. CONSTITUTION:An operation mode determining circuit 12 compares an output frequency command (fo) with a target speed command (fi) to determine an operating mode which is outputted as an operation mode command to an output frequency determining circuit 7, and a timer starting signal is outputted only when an acceleration mode is switched to a steady mode. A timer circuit 13 keeps on outputting an output voltage command hold signal until voltage rise in DC bus due to inertia of load is settled. While the hold signal is inputted, a hold circuit 14 keeps the output voltage command corrected immediately before switching of operation mode. |
