| 摘要 |
PURPOSE:To prevent transient phenomena in switching a control system by performing the control over an AC induction motor in a high speed region and in a medium and low speed region on the rotating speed set out from a reference value in switching respectively over to a synchronous system and an asynchronous system. CONSTITUTION:The rotating speed of an AC induction motor 1 is detected by a detection means 2 such as a pulse generator, etc. When this detected rotating speed exceeds a reference value, a programmable interval timer 112 outputs synchronizing signal pulse. A corrective means composed of a CPU 9, a computing element 18, etc., corrects the initial synchronizing signal pulse to meet the timing of a asynchronous carrier wave. In accordance with this corrected synchronizing signal pulse the detected rotating speed is switched over to a synchronous carrier wave with a sinusoidal wave. The gain of current command immediately after the switching over to the synchronous carrier wave is controlled in inversely proportional to the rotating speed of the motor 1. |
