Low-Sensitivity Slip-Frequency Vector Control Method for Robust Vector Control of Induction Motors

Abstract

A vector control method is necessary for high-efficiency and/or wide-range operations of induction motors. The method requires the phase of the rotor flux, which can be estimated by using the stator and rotor resistances. However, the error between the actual and estimated resistances causes rotor flux estimation error and consequently deteriorates the performance of the vector control. Generally speaking, the influence of the stator resistance error decreases as the speed increases, but not for the influence of the rotor resistance error, which is dependent on the speed. One of the approaches to cope with this problem is to provide the vector control system with robustness against resistance variation. This paper proposes a new slip-frequency vector control method to achieve high robustness to rotor resistance variation; this method has a simple structure similar to simple as the conventional slip-frequency vector control method. The effectiveness and usefulness of the proposed method are verified through extensive experiments.