Initial Speed Estimation Method for Induction Motors Using Regression Analysis and Self-Excited Vibration Phenomenon

Induction motor drive systems without rotation speed sensors are already in practical use in many products. In recent years, the efficiency of induction motors has increased, and the secondary time constant tends to become longer. This paper investigates a new restart method that enables a short startup time for such high-efficiency induction motors. The validity of the new method is verified by experiments using a high-efficiency induction motor.