Online Closed-Loop Autotuning Digital Controller for Switching Power Converters

Abstract

A switching power-converter closed-loop online autotuning controller is presented in this paper. The presented controller is based on tuning the closed-loop-compensator parameters by simply observing the compensated-error-signal time-domain characteristics. Moreover, the presented online autotuning controller does not require the knowledge of the power-stage frequency response, does not depend on any conventional rule-of-thumb control-design criteria such as gain and phase margins, can be used without interrupting the normal operation of the power converter, and is relatively simple when compared to other methods particularly those that require measuring the frequency response of the power stage or closed-loop converter system. The online autotuning controller is presented in this paper based on a dc–dc buck switching converter with a fully digital closed-loop controller, as an example and not for limitation.