Vector control method in sliding mode control of an AC motor

The direct Lyapunov method was used to determine the sliding-mode condition for a vector control variable structure system. This sliding condition enables the use of optimization criteria for selecting the inverter output voltages. A description of the optimization procedure which results in three switching strategies of the inverter that feeds the AC motor is included. The selection of the output voltage for the optimal selected strategy is derived. A problem regarding the definition of reference control quantities is pointed out. The experimental implementation of the proposed control is described, and simulation results are given