| Title |
8kW LLC Isolated Converter Design for ESS Battery Charge/Discharge System |
| Authors |
Jinwoo Kim ; Seunghoon Baek ; Younghoon Cho ; Tae-Geun Koo |
| DOI |
https://doi.org/10.6113/TKPE/2018.23.3.161 |
| Keywords |
LLC resonant converter ; Resonant converter design ; ESS ; Isolated DC-DC converter ; High power density |
| Abstract |
In battery-operated systems, an isolated converter is used to interface the utility grid with the system to increase stability when charging and discharging batteries. Systems such as vehicle-to-grids (V2Gs), on-board chargers, and energy storage systems (ESSs) have recently become popular, and the roles of isolated converters have become important considerations in fabricating such devices. A fixed-frequency LLC converter, which is a type of isolated converter, presents the advantages of high efficiency and high power density by performing zero-voltage switching (ZVS) over wide frequency ranges. However, the magnetizing inductance of the LLC converter should be designed to enable ZVS in all switching devices. Therefore, in this study, the operating characteristics of the LLC circuit are analyzed, and an optimal design method for ZVS operation is established. Moreover, an 8 kW LLC high-efficiency and high-power-density resonant converter is designed and tested for ESS application. The LLC converter achieves 98% efficiency at rated power. |