Sliding-mode approach to control design for induction motor drive fed by a three-level voltage-source inverter

A novel sliding mode control for the induction motor (IM) fed by three-level voltage-source inverter (3L-VSI) is proposed in this paper. The ldquoclassicalrdquo results of sliding-mode theory were extended on the actual variable structure system with more then 2^m variable structures (m is the control space order) by using an original two-step design procedure that allows separately to use the nonlinearity of the IM and the switching character of the 3LVSI. The based on this design procedure original control algorithm that includes a choice condition for 3L-VSI input DC link voltage and a switch table for the 3L-VSI semiconductor switches is designed. The main advantages of such approach are given as follows: the control design is simpler and more graphical; the control system has such advantageous characteristics of the control plant with sliding mode control as high dynamic, low sensitivity to disturbance of both the load and the to plant parameter variations; the requirements to the quality of the input DC-link voltage and as a result to the DC-line filter capacitor are reduced; the measurement precision of the stator flux position is within (pi/6). Simulation results are presented to validate the theoretical analysis and demonstrate the performance of the proposed control.