Periodic oscillations in pulse-modulated systems

Feedback systems employing pulse-modulated actuators are gaining increasing popularity. In the paper, using the A-locus method, general equations have been obtained to solve for limit cycles of various modes in feedback systems employing ¿¿PFM, IPFM and combined pulse modulation (pulse frequency and pulse width). Several theorems have also been presented to find the region of system parameters within which particular oscillations are absent. In addition, some examples have been given to illustrate the results derived, and the solutions have been compared with those obtained by other methods.