Large-Signal Stability Analysis of Two-Stage Cascaded DC/DC Converter Systems Using Sum-of-Squares Programming

The large-signal stability analysis of two-stage cascaded dc–dc converter systems is still a troublesome problem due to various limitations of existing stability analysis methods. To address this problem, a large-signal stability analysis method based on Lyapunov's stability theory and the sum-of-squares programming technique is proposed. With the proposed method, one can not only obtain the maximum stability boundary of the system under large disturbances, which helps understand the system's transient behaviors, but also can analyze the influences of system parameters on the stability region and identify the dominant parameters. The proposed stability analysis method could provide a practical guide for designing system parameters. The effectiveness of the large-signal stability analyzing results is verified by experimental results.