Robust Nonlinear Adaptive Control of a “Boost” Converter via Algebraic Parameter Identification

Abstract

This paper presents the design of a robust nonlinear adaptive controller for trajectory tracking maneuvers of the nonminimum phase output voltage on a dc-to-dc “boost” power converter with uncertain time-varying parameters. The unknown parameter variations concern both the resistive load and the input voltage supply value. A generalized proportional-integral (GPI) indirect control, exploiting the flatness property of the system, performs fast adaptations on the feedback controller and on the desired output reference trajectory owing to a fast online algebraic parameter identification procedure. The required updating of the algebraic parameter identification process is periodically triggered to cope with the time variations of the unknown plant parameters. The proposed control scheme is shown to be quite effective for handling the significant plant uncertainties when tested through experiments on a laboratory prototype. An adaptive linear quadratic regulator optimal control based on feedback linearization was designed in order to compare its performance against that of the proposed GPI adaptive scheme. An integral square error index was used for the evaluation.