  Electric drive using dc shunt motor or permanent magnet dc (PMDC) motor as
prime mover exhibits bifurcation and chaos. The characteristics of dc shunt and
PMDC motors are linear in nature. These motors are controlled by pulse width
modulation (PWM) technique with the help of semiconductor switches. These
switches are nonlinear element that introduces nonlinear characteristics in the
drive. Any nonlinear system can exhibit bifurcation and chaos. dc shunt or PMDC
drives show normal behavior with certain range of parameter values. It is also
observed that these drive show chaos for significantly large ranges of
parameter values. In this paper we present a method for controlling chaos
applicable to dc shunt and PMDC drives. The results of numerical investigation
are presented.
