| 摘要 |
PURPOSE:To suppress vibration in the output current from an inverter by decreasing the negative feedback amount at a predetermined gradient as the increment of intermadiate DC voltage from corresponding AC power supply voltage increases thereby reducing regenerative current. CONSTITUTION:Current of an induction motor 3 is detected through a current transformer 4 and vibration component thereof is detected through a vibration component detecting circuit 6. A conversion operating circuit 7 then performs optimizing operation to product an optimized value Ioc which is fed to a voltage correcting circuit 9. An intermediate voltage increment detecting circuit 8 detects an increment DELTAVdc of actual value from a value corresponding to AC power supply voltage. A voltage correcting circuit 9 multiplies the vibration current component by a conversion factor K to produce a correction value DELTAVs for an output voltage command value Vs, wherein the conversion factor K is decreased at a predetermined gradient as the increment DELTAVdc increases. Vibration of load current can be suppressed smoothly over the entire load variation region of inverter through such operations. |
