Bifurcation behavior & Co-existing attractor of PWM controlled DC drives

This paper describes the bifurcation behavior of a PWM controlled DC drives, where switching boarders are varying periodically with time. The type of system under study covers most of PWM controlled drives where two or more dynamical systems are switched according to the interaction of the control variable with the periodically moving boarders. In particular, the complex bifurcation behavior of a DC series motor is studied in detail. The bifurcation diagrams are obtained by varying different parameters. The occurrence of chaos has been quantified by calculation of Lyapunov exponents. The bifurcation diagrams of the motor drawn with different initial conditions show the existence of coexisting attractors. The space of initial condition drawn to show the basin of attraction of trajectories for period-1, period-2 and period 4 orbits.