摘要 |
A device for controlling an induction motor includes a voltage/frequency controller, a pulse width modulation controller, and a converter. The voltage/frequency controller receives a controlling frequency, and outputs a controlling voltage corresponding to the controlling frequency. The pulse width modulation controller receives the controlling voltage and the controlling frequency, and generates PWM signals according to the controlling voltage and the controlling frequency. The converter receives the PWM signals, and controls the induction motor according to the PWM signals. There is a predetermined relationship between the controlling voltage and the controlling frequency stored in the voltage/frequency controller. The controlling voltage is greater than zero in response to the controlling frequency being zero, and increasing the controlling frequency increases the controlling voltage as in the predetermined relationship.
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