Universal Restart Strategy for Scalar (V/f) Controlled Induction Machines

This paper presents a universal flying restart strategy for scalar (V/f) controlled induction machines. The proposed method performs a frequency search to estimate the rotor speed, and applies the correct frequency and voltage to minimize the inrush current during the restart. This method uses the measured phase current and the motor nameplate parameters, thus making the approach ideal for scalar-controlled motor drives. In addition, the restart algorithm provides controllable restart dynamics, independent of the motor parameters. The main advantages of this method include simple and cost effective implementation without the need for additional sensors, and controllable restart dynamics independent of the motor parameters. Beyond the development of the algorithm, we consider implementation issues to provide a general guideline for the application of the developed algorithm.