A Hybrid DC/DC Converter for EV OBCs Using Full-bridge and Resonant Converters with a Single Transformer

  • Hassan, Najam ul (Department of Electrical Engineering, Myongji University) ;
  • Kim, Yoon-Jae (Department of Electrical Engineering, Myongji University) ;
  • Han, Byung-Moon (Department of Electrical Engineering, Myongji University) ;
  • Lee, Jun-Young (Department of Electrical Engineering, Myongji University)
  • Received : 2016.06.07
  • Accepted : 2016.11.11
  • Published : 2017.01.20


This paper proposes a dc/dc converter for electric vehicle onboard chargers using a secondary resonant tank. To attain soft switching characteristics, such as zero voltage switching, magnetizing inductance has been used at the primary side of the transformer. The leakage inductance of the transformer is used as a resonant inductor on the secondary side to avoid the use of a separate inductor as resonance. The proposed converter is applicable for a wide load range. A 6.6KW prototype has been implemented for a wide range of load variations (250V, 330V, 360V, and 413V). A maximum efficiency of 97.4% is achieved at 413V.


Supported by : National Research Foundation of Korea(NRF), Korea Institute of Energy Technology Evaluation and Planning(KETEP)


  1. A. Y. Saber and G. K. Venayagamoorthy, "Plug-in vehicles and renewable energy sources for cost and emission reductions," IEEE Trans. Ind. Electron., Vol. 58, No. 4, pp. 1229-1238, Apr. 2011.
  2. M. Rosekeit and R.W. De Doncker, "Smoothing power ripple in single phase chargers at minimized dc-link capacitance," in Proc.IEEE ICPE ECCE, 2011, pp. 2699-2703.
  3. A. Khaligh and S. Dusmez, "Comprehensive topological analysis of conductive and inductive charging solutions for plug-in electric vehicles," IEEE Trans. Veh. Technol., Vol. 61, No. 8, pp.3475-3489, Oct.2012.
  4. F. Musavi, M. Craciun, D. S. Gautam, W. Eberle, and W. G. Dunford "An LLC resonant DC-DC- converter for wide output voltage range battery charging applications," IEEE Trans. Power Electron., Vol. 28, No. 12, pp. 5437-5445, Dec. 2013.
  5. Haoyu Wang, Serkan Dusmez, and Alireza Khaligh. "A novel approach to design EV battery chargers using SEPIC PFC stage and optimal operating point tracking technique for LLC converter," in Proc. IEEE Appl. Power Electron. Conf. Expo., pp. 1683-1689, 2014.
  6. B. Ren Lin and W. J Lin, "Half-bridge zero voltage switching converter with three resonant tanks," Journal of Power Electronics, Vol. 14, no 5, pp. 882-889, Sep. 2014.
  7. S. G. Kim and F. S. Kang, "Multifunctional onboard battery charger for plug-in electric vehicles," IEEE Trans. Ind. Electron., Vol.62, No. 6, pp.3460-3472, Jun.2015.
  8. M. Grenier, M. G. Hosseini Aghdam, and T. Thiringer, "Design of on-board charger for plug-in hybrid electric vehicle," in Proc.IEEE PEMD, 2010, pp. 1-6.
  9. H. J. Chae, H. T. Moon, and J. Y. Lee, "On-board battery charger for PHEV without high voltage electrolytic capacitor," Electron. Lett., Vol.46, No. 25, pp. 1691-1692, Dec. 2010.
  10. P. Reid, C. Mittelstadt, and T. Faber, "Electric vehicle conductive charge couplers," in Proc. IEE 60th Holm Conf. Electr. Contacts, 2014, pp. 1-7.
  11. B. K. Lee, J. P. Kim, S. G. Kim, and J. Y. Lee, "A PWM SRT DC/DC Converter for 6.6-kW EV Onboard Charger," IEEE Trans. Ind. Electron., Vol. 63, No. 2, pp. 894-902, Feb. 2016
  12. W. Yu, J. D. Lai, W. H. Lai, and H. Wan, "Hybrid resonant and PWM converter with high efficiency and full soft-switching range," IEEE Trans. Ind. Electron., Vol. 27, No. 2, pp. 4925-4932, Dec. 2012.
  13. C. Liu, B. Gu, J. S. Lai, M. Wang, Y. Ji, G. Cai, Z. Zhao, C. L. Chen, C. Zheng, and P. Sun, "High-efficiency hybrid full-bridge-half-bridge converter with shared zvs lagging leg and dual outputs in series," IEEE Trans. Power Electron., Vol. 28, No. 2, pp. 849-861, Feb. 2013.