A novel modeling approach of LLC resonant converter for embedded controls

Over the past decade, power converters have become more efficient (>96%), offering higher power density at reduced cost. This achievement is due to effective topologies, new components, and the deployment of embedded controls. One of the popular topologies for DC to DC conversion is the LLC resonant topology. Regulation of the LLC converter, operarting over wide range of frequencies, with high bandwidth and sufficient disturbance rejection capabilities is not without challenges due to varying dynamics behavior of the LLC. This calls for non-linear and/or adaptive control deployment through embedded controls. Extensive research has been done, to date, in describing state space modeling for the LLC topology. In this paper, a popular approach of Extended Describing Functions is applied to the LLC converter is analyzed. A new approach of estimation of the LLC dynamics based on Least Squares Method is proposed The proposed algorithm is applied to the simulation model of the LLC. The paper presents the modelling approach, simulation results and assesses the results for future development of adaptive control.