A novel buck-cascaded two-inductor boost converter with integrated magnetics

This work proposes a new buck-cascaded two-inductor boost converter and its integrated magnetics implementation. It is well suited for low input-voltage and high output-current and multioutput applications. It retains the main advantages of the buck-cascaded current-fed push-pull converter, such as wide input voltage range, reduced voltage stresses for the switches in the push-pull stage, and elimination of the need for high current output inductor, which makes it easier to design for multiple outputs. The integration of the transformer and the inductors into a single magnetic structure using the proposed integrated magnetics scheme, achieves several advantages such as reduced core size, reduced AC flux ripple, improved filtering inductance, and continuous output current. The principle of operation of the proposed scheme is explained using the gyrator-capacitor model. Experimental results from a 12 V/5 A proof-of-concept prototype are presented demonstrating the advantages of the proposed scheme.