Current Driven Fractional Power Processor for Ultrafast Charging

Fractional power processing is a probable solution to the growing demand for cost-effective and highly efficient charging systems while handling large power as required in case of ultrafast charging (UFC). This article presents a novel current driven fractional power processor with resonant DAB converter that is suitable for efficient UFC applications. The proposed architecture allows only a fraction of power to be processed through the converter, thus reducing the current and voltage stress across components. This presents reduced component rating along with decreased losses while transferring bulk power through a series path to achieve highly efficient battery charging. The proposed charger utilizes the parallel resonant tank of the converter to impart the current source behavior at the output, which aids in minimizing control requirements. A simple, fixed frequency phase shift control that targets UFC application while ensuring ZVS operation of all switches for efficient charging is utilized. The operation of converter and its performance as UFC are discussed in detail with mathematical model. The performance of the proposed converter is validated through 1.32 kW scaled-down laboratory developed prototype. Its performance is compared in detail with conventional charger to establish the design and performance benefits.