Describing function-based analysis of a class of PWM feedback control systems

This paper discusses the application of the dual-input describing function method to the analysis of closed loop pulse width modulated systems. Such method is here considered based on the use of the Kapteyn series, which allow to obtain a simple stability criterion that gives sufficient conditions for the absence of limit cycles of period multiple of that characteristic of the modulator. Some simulation results confirm the validity of the proposed criterion which can be considered a useful design tool for the selection of some parameters of the modulator although, in some cases, the result could be conservative.