Single-loop order reduction output voltage control with model-free filtering for DC/DC converters

Abstract

This study devises an advanced single-loop output voltage control method for DC/DC converters incorporating a model-free filter, active damping, and nonlinearly designed feedback terms. The resultant output-feedback controller ensures the order reduction property and reduces both the dependence level of the system model and the number of feedback loops. There are two main features that differentiate this from extant results. First, a model-free first-order pole-zero cancellation (PZC) filter extracts the time derivative component from the output voltage measurement according to the first-order dynamics by the order reduction property without any converter model information. Second, an active damping controller forming a modified proportional-integral-derivative structure tracks the output voltage to its desired trajectory along the first-order low-pass filter dynamics by the order reduction property from the PZC, which is independent of the current feedback. Experimental evidence obtained from an actual feedback system adopting a 3-kW prototype DC/DC converter validates the effectiveness of the proposed technique, which demonstrates the capability of the current sensor fault tolerance.