| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method of controlling an induction motor which can drive the induction motor whose rotation speed is unknown without excessive current and without requiring a speed meter and a high-performance controller. <P>SOLUTION: When an inverter circuit 21 is controlled in an estimation mode, the frequency of the output voltage of the inverter circuit 21 changes, the instantaneous value of power to be supplied from the inverter circuit 21 to the induction motor 3 changes. If a slip value of the induction motor 3 becomes zero, the instantaneous value of power to be supplied to the induction motor 3 becomes zero. When the frequency of output voltage of the inverter circuit 21 in which the instantaneous value of the power acquired by an output power calculating unit 26 becomes zero is detected in a state where the inverter circuit 21 is controlled in the estimation mode, the inverter circuit 21 is controlled in a driving mode from this frequency, thereby preventing the induction motor 3 from having excessive current. Thus, V/F of the induction motor 3 can be controlled in a constant state. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
