FEA-Based Optimisation of an Inserted-Shunt Integrated Planar Transformer for a Bidirectional CLLLC Resonant Converter

This paper presents an optimisation method for an inserted-shunt integrated planar transformer based on 3D simulation in Ansys Maxwell. The optimisation objective is enhanced efficiency and power density for the transformer. Thermal analysis verifies the optimisation to ensure the transformer's operability under limited temperature conditions when its size is reduced. The optimised integrated transformer is implemented for verification, with the presentation of experimental results, including AC resistance, efficiency, operating waveforms, and thermal imagery. Furthermore, the paper provides insight into the loss distribution of the transformer. The study shows that the optimisation enhances the power density of the inserted-shunt integrated planar transformer by 270% compared to the conventional design. Additionally, the CLLLC converter incorporating the optimised transformer achieves approximately 1.84 percentage points higher efficiency than the conventional design.