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http://dx.doi.org/10.6113/TKPE.2016.21.6.506

Analysis for Light Load Regulation of LLC Converter using Bode Plot  

Yeon, Cheol-O (School of Electrical Engineering, KAIST)
Moon, Gun-Woo (School of Electrical Engineering, KAIST)
Publication Information
The Transactions of the Korean Institute of Power Electronics / v.21, no.6, 2016 , pp. 506-513 More about this Journal
Abstract
In general, LLC converters show great promise in applications that require high efficiency, especially under light load conditions. In particular, LLC converters feature wide gain capability with pulse-frequency modulation and zero voltage switching over entire load conditions. However, output voltage increases in light load conditions. In this study, Bode plot and impedance asymptotes analyses were conducted to obtain insights into the regulation characteristics of LLC converters under light load conditions. To improve the regulation characteristic of LLC converters, a new resonant tank with an additional capacitor is proposed. The design guideline for the proposed LLC converter is determined by the Bode plot and impedance asymptotes analyses. Therefore, the proposed LLC converter achieves the light load regulation while maintaining the advantages of typical LLC converters.
Keywords
LLC converter; Light load regulation; Parasitic components; ZVS(Zero-Voltage-Switching); Bode plot; Impedance asymptotes;
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Times Cited By KSCI : 1  (Citation Analysis)
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1 B. Yang, F. C. Lee, A. J. Zhang, and G. Huang, "LLC resonant converter for front end DC/DC converter," in Proc. Applied Power Electronics Conference and Exposition, APEC'02, Vol. 2, pp. 1108-1112, Mar. 2002.
2 N. Majid, J. Janczak, and E. G. Patrick, "Resonant mode power supply having an efficient low power stand-by mode," U.S. Patent 6018467, Jan. 2000.
3 Y. Fang, D. Xu, Y. Zhang, F. Gao, L. Zhu, and Y. Chen, "Standby mode control circuit design of LLC resonant converter," in Proc. Power Electronics Specialists Conference, PESC'07, pp. 726-730, Jun. 2007.
4 J. Qin, Z. Moussaoui, J. Liu, and G. Miller, "Light load efficiency enhancement of a LLC resonant converter," in Proc. Applied Power Electronics Conference and Exposition, APEC'11, pp. 1764-1768, Mar. 2011.
5 C. E. Kim and G. W. Moon, "High-efficiency low-profile on-board DC/DC converter for digital car audio amplifier," Electron. Lett., Vol. 401, No. 10, pp. 571-572, May 2004.
6 C. E. Kim, K. B. Park, G. W. Moon, and J. Y. Lee, "New multi-output LLC resonant converter for high efficiency and low cost PDP power module," in Proc. IEEE Power Electronics Specialists Conference, PESC'06, pp. 1-7, Jun. 2006.
7 Y. Gu, Z. Lu, L. Hang, Z. Qian, and G. Huang, "Three-level LLC series resonant DC/DC converter," IEEE Trans. Power Electron., Vol. 20, No. 4, pp. 781-789, Jul. 2005.   DOI
8 B. Lu, W. Liu, Y. Liang, F. C. Lee, and J. D. van Wyk, "Optimal design methodology for LLC resonant," in IEEE Proc. Applied Power Electronics Conference and Exposition, APEC'06, pp. 533-538, Mar. 2006.
9 H. Choi, "Design consideration of half-bridge LLC resonant converter," Journal of Power Electronics, Vol. 1, No. 1, pp. 13-20, Jan. 2007.
10 B. Lee, M. Kim, C. Kim, K. Park, and G. Moon, "Analysis of LLC resonant converter considering effects of parasitic components," in Proc. Telecommunications Energy Conference, INTELEC'09, pp. 1-6, Oct. 2009.
11 J. Kim, C.Kim, J. Kim, and G. Moon, "Analysis for LLC resonant converter considering parasitic components at very light load condition," in Proc. Power Electronics and ECCE Asia, ECCE Asia' 11, pp. 1863-1868, May. 2011.
12 B. McDonald and F. Wang, "LLC performance enhancements with frequency and phase shift modulation control," in Proc. Applied Power Electronics Conference and Exposition, APEC'14, pp. 2036-2040, Mar. 2014.
13 Y. Lo, C. Lin, M. Hsieh, and C. Lin, "Phase-shifted full-bridge series-resonant DC-DC converters for wide load variations," IEEE Trans. Ind. Electron., Vol. 58, No. 6, pp. 2572-2575, Jun. 2011.   DOI
14 J. Kim, C. Kim, J. Lee, Y. Kim, H. Youn, and G. Moon, "A simple control scheme for improving light-load efficiency in a full-bridge LLC resonant converter," in Proc. Power Electronics Conference, ECCE Asia'14, pp. 1743-1747, May 2014.
15 B. Wang, X. Xin, S. Wu, H. Wu, and J. Ying, "Analysis and implementation of LLC burst mode for light load efficiency improvement," in Proc. Applied Power Electronics Conference and Exposition, APEC'09, pp. 58-64, Feb. 2009.
16 C. Yang, T. Taiwan, T. Liang, K. Chen, J. Li, and J. Lee, "LLC resonant converter controller with novel light load control," in Proc. Electronics and Application Conference and Exposition, PEAC'14, pp. 131-135, Nov. 2014.
17 J. Qin, Z. Moussaoui, J. Liu, and G. Miller, "Hysteretic control of LLC resonant converter for solar and DC-DC applications," in Proc. Control and Modeling for Power Electronics, COMPEL'10, pp. 1-5, Jun. 2010.
18 R. Oruganti, J. Yang, and F. Lee, "Implementation of optimal trajectory control or series resonant converter," IEEE Trans. Power Electron., Vol. 3, No. 3, pp. 318-327, Jul. 1988.   DOI
19 L. Rossetto, "A simple control technique for series resonant converters," IEEE Trans. Power Electron., Vol. 11, No. 4, pp. 554-560, Jul. 1996.   DOI
20 W. Feng, F. Lee, and P. Mattavelli, "Optimal trajectory control of burst mode for LLC resonant converter," IEEE Trans. Power Electron., Vol. 28, No. 1, pp. 457-466, Jan. 2013.   DOI
21 I. Lee and G. Moon, "The k-Q analysis for an LLC series resonant converter," IEEE Trans. Power Electron., Vol. 29, No. 1, pp. 13-16, Jan. 2014.   DOI
22 J. Jung and J. Kwon, "Theoretical analysis and optimal design of LLC resonant converter," in Proc. Power Electronics and Applications, pp. 1-10. Sep. 2007.
23 R. Beiranvand, B. Rashidian, M. Zolghadri, and S. Alavi, "Using LLC resonant converter for designing wide-range voltage source," IEEE Trans. Ind. Electron., Vol. 58, No. 5, pp. 1746-1756, May. 2011.   DOI
24 D. Fu, F. Lee, Y. Liu, and M. Xu, "Novel multi-element resonant converters for front-end DC/DC converters," in Proc. Power Electronics Specialists Conference, PESC'08, pp. 250-256, Jun. 2008.