| Title |
A 40kW, 100-1000V Output DC/DC Unit Power Module for EV Fast Chargers |
| Authors |
Se-Young Bae ; Dal-Hyeon Cho ; Min-Gi Choi ; Joo-Eun Kim ; Il-Oun Lee |
| DOI |
https://doi.org/10.6113/TKPE.2023.28.6.470 |
| Keywords |
Electric vehicles; Fast charger; Rapid charger; Llc resonant converter; and Wide output voltage range |
| Abstract |
In this study, a 40 kW, 100-1000 V output direct current (DC)/DC unit power module, which is composed of two inductor-inductor-capacitor (LLC) resonant converters, is proposed for electric vehicle fast chargers. The primary inverters of the two LLC resonant converters are arranged in parallel, but the secondary rectifiers are connected in series or parallel depending on the output voltage conditions. Each LLC converter uses two transformers, and the primary windings of the two transformers are connected in parallel, while the secondary windings are connected in series to balance the power handled by the two transformers. To achieve high efficiency, the two LLC resonant converters are designed to operate primarily at the resonant frequency, and all semiconductors used on the primary side are designed with 1200 V-based SiC metal-oxide-semiconductor field-effect transistors. The secondary rectifying diodes are designed based on 600 V, and a method for minimizing leakage inductance in the transformer is investigated to reduce losses caused by leakage inductance. The performance of the proposed unit is verified in a prototype with 100- 1000 V and 40.0 kW class specification. It achieves a maximum efficiency of 97.8% under 800 V and 40 kW conditions. |