Analysis and Design of an Adaptive-Step-Size Digital Controller for Switching Frequency Autotuning

An adaptive-step-size autotuning algorithm and controller for power converters´ switching frequency optimization with improved convergence performance is presented in this paper. The controller automatically tracks and determines the switching frequency of a power converter in order to achieve the highest power conversion efficiency under variable operating conditions including temperature variation effects, component aging effects, component´s manufacturing process differences, input voltage changes and load current changes. The adaptive-step-size function results in improved adaptive controller convergence speed, convergences error and stability. In this paper, the proposed autotuning control loop for a power converter is theoretically analyzed and its design and stability criteria are developed. The developed algorithm operation is verified by experimental results obtained from a proof of concept prototype.