RECURRENCE PLOT BASED STUDY OF DIRECT TORQUE CONTROLLED INDUCTION MACHINES

The strange behavior of Direct Torque Controlled (DTC) Induction Machine (IM) due to nonlinearity is studied. The nonlinearity is the result of hysteresis comparators. Recurrence Plots (RP) beside the bifurcation diagram are applied to reveal the possible states of the system such as periodic, subharmonic and chaotic states. RP makes it possible to identify various system states without the knowledge of all state variables in a multi-dimensional system, it is enough to acquire only time series of an observable state.