Split Duty Cycle Coupled Multi-phase Boost-Buck Converter

The classic boost and buck cascaded converter has an inductor at the input and output ports of the converters, which makes it ideal for bidirectional battery charging applications where accurate current control and low ripple currents are required. This paper proposes a novel split duty cycle coupled multi-phase variant of the cascaded boost-buck converter, suitable for bidirectional operation where the low voltage port has high current, requiring a multi-phase buck stage. The paper covers split duty cycle converter operation principle using coupled inductors between input and the multi-phase output with magnetic component design and selection guidelines. The proposed control method and coupled inductor structure are validated by simulation and experimental results.