| 摘要 |
PURPOSE:To smoothly vary the output frequency of an inverter by converting a frequency command signal to an analog signal, further converting the voltage into a frequency, and driving a ring counter by the output signal to obtain a frequency command signal. CONSTITUTION:A digital parallel signal corresponding to a frequency command signal is D-A converted by a D/A converter 21 into an analog signal. This analog signal is inputted through a filter 22 to a voltage/frequency converter 23 which converts again into a serial signal. Then, a ring counter 11 is driven by the output signal of the converter 23 to obtain a frequency command signal. Thus, frequency information which smoothly varies is obtained, and the output frequency of the inverter can be smoothly varied. |
