A Study on the Stability of Current-Mode Control Using Time-Delay Model of Pulse-Width-Modulator

摘要

This paper concentrates on the dynamic behavior of pulse-width-modulator (PWM) and the time-delay introduced in the modulation process is highlighted.In order to describe this effect,we derive a time-delay model,based on which the closed-loop stability of current-mode control is studied and a novel interpretation of the subharmonic oscillation is presented.Compared to its existing counterpart,the proposed model exhibits the following superiorities: (a) possesses a simpler mathematical expression;(b) gives more physical insight into the sample and hold effect of current loop;(c) provides a better prediction of the critical condition of the current loop stability without slope compensation in engineering practice.This novel time-delay model is validated by simulation results.