Patent Number: 6,166,514

Title: Apparatus and method for controlling induction motor

Abstract: In a control apparatus of an induction motor including an inverter for converting a direct current to an alternating current having a variable voltage and variable frequency in accordance with a pulse width modulation control, and a controller for controlling an output voltage of said inverter through a modulation rate which is requested in accordance with an exciting magnetic current component command in a primary current of the induction motor driven by said inverter and a voltage component command corresponding to said respective components which are executed in accordance with a torque current component command, the control apparatus of the induction motor operates to detect a torque current component in accordance with said primary current of the induction motor, to correct said torque current component from a deviation between said detected torque current component value and said command value, to correct an output frequency of said inverter in accordance with said corrected torque current component command, and to limit the size of the modulation rate to less than a predetermined value or less than a predetermined condition. With this construction, in the induction motor, without the change-over from the low speed area to the high speed area (PWM pulse mode is 1 pulse area) where the size of the voltage command exceeds the maximum voltage capable of being output by the inverter, which is determined according to the direct current voltage, a good vector control can be carried out.

Inventors: Ando; Takeshi (Hitachinaka, JP), Tanamachi; Tokunosuke (Hitachinaka, JP), Toyota; Eiichi (Hitachinaka, JP), Nakata; Kiyoshi (Iwase-machi, JP), Suzuki; Masato (Urizura-machi, JP), Yasuda; Kouji (Hitachinaka, JP)

Assignee: Hitachi, Ltd.

International Classification: B60L 15/02 (20060101); B60L 15/00 (20060101); H02P 21/00 (20060101); H02P 21/08 (20060101); H02P 21/06 (20060101); H02P 001/26 ()

Expiration Date: 12/26/2017