Linearization Method for Starting Control of Speed-Sensorless Vector-Controlled Induction Motors

A linearization method is proposed for controlling the start-up operation of a rotating induction motor. The dynamics of this motor are deteriorated when the starting operation is carried out at high frequencies. In this method, the characteristics of the method are analyzed to reveal that the aforementioned problem is caused by the low equivalent gain of the induced voltage during the rotor flux establishment. A method to compensate for the angle of the rotor-flux-induced voltage vector is proposed to overcome this problem. The proposed method is experimentally verified by a test set, and the influence of changes in the rotor resistance is analyzed.