Feedback linearization control of non-inverting buck-boost PV power optimizers

In this paper, a novel control design based on a feedback linearization control (FLC) technique is developed for a Photovoltaic (PV) power optimizer implemented on a non-inverting buck-boost power converter. Unlike the classical local linearization techniques commonly used in the technical literature, this approach allows to obtain large-signal linear equations, by means of the feedback linearization of the non-linear terms. The non-linear model of the buck-boost converter operating in both buck and boost modes is presented, followed by the exact linearization and decoupling model using the FLC technique. From this linearized model, simple proportional and proportional-integral controllers are designed for the inner current and outer voltage control loops, respectively, in a cascaded control strategy. Simulation results demonstrate the effectiveness of this control technique, capable of regulating the PV voltage with consistent transient response, independent of the operating point of the PV source.