Analysis and Theoretical Comparison of 1-to-1.5 Resonant Switched Capacitor Converters for High-Voltage EV Batteries

System voltages of electric vehicles (EVs) are increasing from 400 V to 600–800 V to reduce charging time and to extend cruising distance. However, ordinary 500-V charging stations cannot directly be applied to such high voltage EV systems. This paper proposes and analyzes resonant switched capacitor converters (RSCCs) as on-board boost converters with 1-to-l.5 voltage conversion ratio that can bridge the voltage gap between the charging station and EV batteries. Three RSCC topologies are analyzed in detail and are compared from the viewpoint of power conversion efficiency and power density.