Auto-tuning sliding mode control for induction motor drives

Sliding mode control offers great potential to deal with uncertainties such as parameter variation and external load disturbances in controlling induction motor drives. The main obstacle of conventional sliding mode control is the presence of chattering phenomenon. It is known that the large switching gain of sliding mode control is proportional to the chattering level, and normally a large switching gain is applied to handle the uncertainties. In this paper, this chattering phenomenon is significantly reduced by a newly developed algorithm. The control algorithm incorporates the adjustment of switching gain value and variation of the boundary layer to replace the discontinuous function in conventional sliding mode control. As a result, the boundary layer and the switching gain will change in the presence of uncertainties and load disturbances. The experimental results show the effectiveness of the proposed sliding mode control is superior in reducing the chattering phenomenon and handling the external load disturbances.