| 摘要 |
PURPOSE:To completely suppress the vibration of an AC motor without the type and the load of the motor nor the operating conditions such as th speed range by detecting the input current of an inverter and controlling the frequency of the inverter through a power compensator. CONSTITUTION:A current transformer 13 detects the input current ID of an inverter. This detection signal is inputted through a DC current polarity discriminator 14, a stabilization discriminator 15, a power compensator 30, a limiter 18 and a gain converter 19 to an adder 20, and added to a frequency set signal fR. Thus, when a motor abnormally vibrates, a stabilization signal having the same polarity as the basic frequency command of the inverter from when a negative DC current starts flowing and rising at the time constant within approx. twice to three times of a carrier period is added to the basic frequency of the inverter, and a stabilization signal having entirely reverse sign and symmetrical to the above stabilization signal is added thereto from when a positive DC current starts, on the contrary, flowing to suppress the vibration. |
