Nonlinearities stabilization using dithering injection in permanent magnet DC motor system

This paper presents the used of dither signal injection technique to stabilize the effect of nonlinearities in feedback control system. Various form of dither has been proposed including square wave, sine wave, and triangle wave dither. The analytical study of modified nonlinear element concept and simulation results show that square wave dither required the minimum amplitude to eliminate the ‘hunt’ (self-oscillation) or limit cycles but the triangle wave dither signal has the best ability to eliminate the limit cycle because its actual of output signal is closest to the reference signal and smoothest than others.