Chaotification of permanent-magnet synchronous motor drives using time-delay feedback

Research has shown that chaos can actually be useful under certain circumstances, and there is growing interest in utilizing the very nature of chaos. Thus, a controllable chaotic motor drive, namely chaotifying a motor drive, is highly desired for practical engineering systems. This paper firstly proposes and implements a time-delay feedback method to chaotify a practical permanent-magnet synchronous motor (PMSM) drive. Based on the current-fed model and field-oriented control, the corresponding system dynamics will be approximated by first-order differential equations. Hence, the electromechanical torque will be adjusted according to the time-delay speed feedback. Consequently, chaotic motion can be achieved by tuning the feedback gain of the torque controller. Moreover, the resultant chaotic motion is easily controllable in the sense that the rotor speed boundary can be controlled precisely by the value of the speed ratio. This controllable chaotic PMSM drive potentially offers some special applications desiring chaotic motion such as fluid mixing and surface grinding. Theoretical analysis, computer simulation as well as experimental results will be given to verify the proposed method of chaotification.