Coupled Inductor Analysis and Finite Element Modeling Assisted Design for Boost Extender Topology

Theoretical and finite element analysis of four coupled inductor structures based on the common cores suitable for Boost Extender topology is presented. The impact of each setup on the boost extender topology is evaluated and a design method that targets optimal operation point of the converter is demonstrated. Coupled inductors built around the most popular EE and UU cores are examined. The impact on the self-inductance of each winding and the coupling coefficient between the windings as a function of the air gap size and location are evaluated. It was found that a UU core structure based coupled inductor is a good candidate to address the challenges of the losses and parasitic ripple generated due to the coupling between the two inductors in the boost extender converter. Theoretical predictions agree well and are complemented by a finite element magnetic simulation software suite ANSYS Maxwell, which is then validated experimentally on a full scale 100W experimental prototype.