Small‐signal‐based study of a two stage AC/DC and DC/DC battery charger using battery one time constant model

Abstract

This study focuses on considering battery one time constant model in the design of controllers of a two-stage AC/DC and DC/DC battery charger using the small-signal approach. For this aim, small-signal models of DC/DC and AC/DC converters and also the battery model are obtained. Moreover, the effect of disturbance terms are analysed to be omitted in controller loops. Simulation and experimental results of a 1 kW laboratory prototype show appropriate performance of designed controllers in tracking reference signals. Also, tuned controllers using this approach have guaranteed unity power factor and low total harmonic distortion. Furthermore, a complete charge cycle of a lithium-ion battery evaluates the performance of the converter in different constant current/voltage controlling modes. In comparison with restive model consideration, results show a more accurate model with grater damping ration and better stability characteristics.