Work

Folded Flex-PCB Winding Planar Transformer for High-Frequency Isolated DC-DC Converters

Year: 2025

Type: conference-paper

Abstract: In modern high-frequency DC-DC converters such as electric vehicle (EV) chargers, transformers can commonly contribute to ~45% of the losses and a third of the box volume. Meanwhile, the magnetics can strain such converters’ thermal management and electromagnetic interference (EMI), especially when targeting high power densities. This underlines the need for innovative solutions in magnetic design. One such innovation arises from recent advancements in flexible printed circuit board (PCB) manufacturing, allowing highly interleaved windings with sufficient copper thickness while eliminating termination losses between PCB boards. Therefore, this paper assesses flex-PCB designs for high-frequency transformers in EV chargers, addressing challenges and opportunities to conventional PCB-winding designs. The key modelling and trade-offs are detailed, considering the impact of parasitic capacitance, core loss, winding loss, leakage inductance, and thermal management for different configurations. From the analytical and simulation results, a design candidate with low transformer loss and parasitic effect is selected and experimentally characterised for its implementation in a 500 kHz CLLC converter.

Source: IEEE Applied Power Electronics Conference and Exposition (APEC)

DOI: 10.1109/apec48143.2025.10977556

Authors: Soundhariya G. Soundararajan, Hans Wouters, Wout Vanderwegen, Wilmar Martinez

Institution: KU Leuven

Language: English

Topic: Advanced DC-DC Converters

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Industry, innovation and infrastructure, Affordable and clean energy

Open Access status: green

Funder: HORIZON EUROPE Framework Programme