Efficiency Comparison of DAB Module for LVDC-Connected EV Fast Charging Systems
Year: 2025
Type: conference-paper
Abstract: Addressing key challenges in the roadmap toward transportation electrification requires more grid flexibility and highly efficient modular fast charging systems capable of wide voltage operation in line with evolving EV battery voltage levels. This paper investigates optimal system configurations for Dual Active Bridge (DAB) modules connected to a bipolar LVDC grid ($+/-350 \mathrm{V}$), targeting 400 V and 800 V battery systems. DAB module designs are based on real-world charging voltage and power profiles. Using detailed PLECS-based simulations incorporating SiC MOSFET and high-frequency transformer models, the switching and conduction losses are analyzed across varying operating conditions. Results show that ultra-high efficiencies ($>99 {\%}$) are achievable at higher voltage levels ($700-800 \mathrm{V}$), although switching losses increase at lower charging power. At lower voltage operation ($350-400 \mathrm{V}$), a narrower efficiency range$(92 \%-98 \%)$is observed across the full power range. Therefore, from the DAB module perspective, this configuration can be optimal to maintain higher efficiency over a wide charging power range, particularly when battery and LVDC grid voltages are closely matched. For a 150 kW IPOP modular fast charger, high voltage operation ($700-800 \mathrm{V}$) results in lower total losses ($1.5-3 \text{kW}$), making it the preferred configuration for typical fast-charging profiles.
Authors: Mohamed Yasko, Diego Bernal, Wilmar Martinez, Johan Driesen
Institution: KU Leuven
Language: English
Topic: Advanced DC-DC Converters
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4412987015