From Components to Converters: A Fundamental Topology Derivation Method for Nonresonant DC-DC Converters Based on Graph Theory

The past 20 years witnessed the invention of numerous converters by utilizing various topology derivation methods. Unfortunately, most of these methods are limited by pre-existing topologies or specific cells, causing the omission of some potentially valuable topologies. To break the limitations, a fundamental topology derivation method, namely components to converters (C2C), is proposed for nonresonant dc-dc converters. The basic idea of C2C is intuitively to derive topologies by combining separate components and filtering out valid combinations. Theoretically, C2C can derive converters more comprehensively since its results are not restricted by firm connections of the existing topologies or cells. However, C2C faces a heavy computing load caused by the massive combinations of components. Hence, a two-stage C2C topology derivation strategy is designed to alleviate the computing load. Furthermore, graph theory and dynamic programming are applied to computerize and optimize the above two-stage C2C. The two-stage C2C is utilized to derive single-switch two-port converters and single-inductor multiple-port converters. The derivation results show that all existing topologies with given components and numerous new topologies are derived automatically and simultaneously. Compared with the existing topology derivation methods, the proposed two-stage C2C is more thorough and automatic, facilitating more converters to meet various demands in practical applications.