A Novel AHB/LLC Combo Converter Using Numerical Optimal Trajectory Control for Wide Voltage Gain Applications

The latest universal serial bus (USB) power delivery 3.1 quick charger, requiring 5–48 V output and 240 W maximum output power, demands a wide voltage conversion ratio on the ac–dc converter topology. The traditional solution, either using LLC or asymmetrical half-bridge (AHB) topology, suffers from the compromise of efficiency and voltage gain. This article proposed a novel AHB/LLC combo converter that realizes high efficiency at different output voltage levels. Combined with a novel numerical optimal trajectory control method, the converter could seamlessly switch between two operation modes and thus enjoy the extraordinary dynamic performance. The proposed topology and control method are verified on a 240-W prototype, achieving 97.98% peak efficiency and good dynamic regulation during load transient.