| 摘要 |
PURPOSE:To eliminate the decrease in the accuracy of controlling the current of an induction motor in a high speed range by employing a plurality of high pass filters of different cut-off frequencies for a high pass filter. CONSTITUTION:When a low speed range, i.e., a ulse number is plural, the detected value of a current transformer group 3 is fed back to an inverter 1 through a high pass filter group 41, and the harmonic component in a low speed range can be effectively removed. When a high speed range, i.e., a pulse number is 1, the detected value of the current transformer group 3 is fed back to the inverter 1 through a harmonic filter group 42 to filter only the harmonic components. Accordingly, the accuracy of controlling the current of induction machine group 2 is not lowered in a high speed range. |
