| 摘要 |
PURPOSE:To obtain a drooping function in a four quadrant operations by utilizing the fact that the polarity of a slip frequency is inverted by power drive and regeneration, inverting the positive/negative polarity of a torque current to the polarity of a slip frequency, and adding it to speed command. CONSTITUTION:When an inverter I is connected to an induction motor 10 to perform power drive or regenerative operation, a motor current is detecte by a current transformer 4, rectified, a constant matched to the slope of drooping is multiplied by a constant setter 11 to subtract it by an exciting current, and inputted to a torque current polarity discriminator 8. A code is converted corresponding to the polarity of the slip frequency in response to the operating state of normal rotation, reverse rotation, power drive or regeneration, added to a speed command 6, corrected, compared it with a motor speed to obtain a slip frequency, and the motor speed is further added, and the inverter I is controlled through a controller III. Acrodingly, whether it is the power drive or the regeneration is judged in a simple sturcture to increase or decrease the speed command, thereby obtaining the drooping function of four quadrants. |
