| 摘要 |
PURPOSE:To improve the response and resolution of an induction motor by driving the motor at a high speed by a commercial frequency in the range of large deviation voltage and at a low speed by a converter frequency in the range of small deviation voltage. CONSTITUTION:A reference voltage which is set by a speed setter is applied to an input terminal, and is applied to a subtractor 2. The output voltage from a rotation detector 4 which generates a voltage responsive to the rotating speed of an induction motor 3 is applied to the subtractor 2, and the difference between the values, i.e., the deviation a is outputted. This deviation a is applied through a variable gain amplifier 5 and an integrator 6 to a comparator 9, the output of which is applied to a pulse generator 10 and a drive circuit 11. When the deviation a is lower than the reference, the motor 3 is driven by the converter frequency which becomes lower proportional to the deviation a. And when the deviation a is higher than the reference voltage, the motor 3 is driven according to the commercial frequency. |
