A Study of Fixed-Structure Variable-Parameter Digital Controller Based on Fuzzy Control for DC/DC Converters

The rapid development of digital control technology provides a new approach to applications of modern control theory and algorithm in power supplies. Firstly, the paper presents a digital DC/DC converter regulated by a fixed-structure variable-parameter PID (proportional-Integral-differential) controller and analyzes the limitations if a large signal disturbs the system; secondly, the feasibility of a compound controller including fuzzy and PI is demonstrated based on the model-independent of fuzzy control; last, fuzzy control is applied to determine the switching condition of variable-parameter PID controller. Simulation and experiment indicate that the vibration and bounce-back at the switching instants can be solved by the introduction of fuzzy control and the robustness of DC/DC converter is improved.