| 摘要 |
PURPOSE:To avoid an instability under control and to prevent an unstable phenomenon due to an insufficient voltage by providing a torque current set value variable limiter for monitoring an ignition angle to detect an insufficient voltage, and limiting a torque current. CONSTITUTION:A torque current set value variable limiter 50 monitors the ignition angle of a thyristor to be formed by a gate controller 11, and gradually limits a torque current reference when the ignition angle arrives at an ignition angle limiter for a set time or more. When the torque current reference is reduced, a voltage to be applied to an induction motor 36 is reduced, and the angle does not reach the limiter. Thus, an instability under control can be avoided. |
