Nonlinear analysis of direct torque controlled induction machines

The nonlinear phenomena of direct torque controlled (DTC) induction machine (IM) is investigated. Since the system is strongly nonlinear due to the hysteresis comparators, various nonlinear phenomena are expected. The objective of the paper is the study of these behaviors, exploring various system states from regular periodic operations to chaotic ones. The main goal is twofold, first by obtaining a deeper insight into the operation of DTC-IM the design of control parameters (width of hysteresis loops) can be supported with the help of the techniques of nonlinear dynamics such as Poincare maps and Bifurcation diagrams, secondly the sudden changes of system states or bifurcations expected due to the nonlinearities can be detected and studied.