Linear State-Feedback Control of a Buck-Boost Converter Using Passivity Technique

Abstract

This work presents the use of the passivity technique applied on a circuitorientedmodel of a switching buck-boost regulator including state-feedback. The procedure, which provides large-signal stability, is implemented for a control law that is a linear combination of the state variables of a buck-boost dc-dc converter. The converter's large-signal equivalent circuit is derived from the its bilinear description. The condition for stability is obtained by studying the condition for passivity of the resulting two-port. Considering stability, the saturation of the control signal is also taken into account. Once the large-signal stability has been guaranteed, the linear model of the converter and the root locus method are used to achieve proper values of the loop gain in order the desired transient response to be obtained. Simulations are in good agreement with analytical results