General mathematical characterization and configuration optimization design method for a multi-mode hybrid power system

Current offline optimization design methods for hybrid power system (HPS) configurations can only explore the energy-saving potential of specific configurations (e.g., single-planetary gear HPSs or dual-planetary HPSs) through topological derivation. To address this issue, this study investigates three fundamental decoupling forms of HPSs and derives a mapping relationship between seven basic configurations and 127 multi-mode HPS configurations. Additionally, we establish a general mathematical characterization method for multi-mode HPSs. Based on this foundation, an optimization design method for multi-mode HPS configurations is developed. Furthermore, the effects of the configuration type and parameters on fuel economy are explored. It was found that the increase in hybrid modes improves energy-saving potential, but this benefit plateaus once the number of hybrid modes reaches three. Finally, using this method as a theoretical basis, configuration optimization design is performed for two specific cases, resulting in a multi-objective optimal solution set containing nine multi-mode HPS configurations, achieving the forward design of a multi-mode HPS configuration structure, and indicating the effectiveness of this method as a novel approach to facilitate the rapid development of multi-mode HPS configurations.