| 摘要 |
PURPOSE:To reduce the capacity of an inverter and the output loss in the high frequency in the low frequency region, by increasing a voltage of a motor in proportion to a frequency region, adjusting the voltage to a maximum one of the inverter after a frequency reaches a particular one and controlling the output along a load curve. CONSTITUTION:A voltage of an induction motor equipped with an inverter is increased in proportion to a frequency in the low frequency region. When the allowable lower limit coefficient is suitably selected from the range of 0.71 to 1.00 and a frequency reaches one at a voltage bending point obtained on the basis of the calculating formula, the voltage is adjusted to the maximum output one of the inverter thereafter and the output of the induction motor is controlled approximately along a load curve. Thus, the capacity of the inverter can be reduced to about 1/3, and the output of the induction motor in the high frequency region is suppressed, so that useless loss can be avoided. |
