A Comparative Study of Voltage Gain Tolerance in Conventional and Three-Level LLC Converters Against Circuit Variation

Hiroyuki Haga, Hidenori Maruta, Fujio Kurokawa


This paper clarifies the relationship between voltage gain tolerance and normalized design parameters against resonant circuit components variation for mass production of LLC converters and three-level LLC converters. The LLC converter is an attractive solution for high power application, hence many photovoltaic systems which use LLC converter have been proposed. The multi-level LLC converter is also proposed to overcome a drawback of the conventional LLC converter. It is important on mass production stage to clarify the relationship between its voltage gain tolerance and design parameters against resonant circuit component variations, however it has rarely studied. Therefore, we study the relationship between voltage gain tolerance and three normalized design parameters related to the resonant circuit with Monte Carlo simulation. As a result, it has found that a conventional LLC converter and a three-level LLC converter have approximately same voltage gain tolerance characteristics. However the three-level LLC converter has a superior performance compared to the conventional LLC converter in aspect of the voltage gain tolerance. The reason for a difference of the performance comes from a design constraint. By utilizing this knowledge, designers can reduce unnecessary losses of the conventional and the three-level LLC converter which are generated by too much voltage gain margin; therefore this paper can contribute to improving performance in renewable energy generation systems.


tolerance; variation; three-level; LLC; Monte Carlo

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Eun-Soo Kim, Sung-In Kang, Kwang-Ho Yoon and Yoon-Ho Kim, "A contactless power supply for photovoltaic power generation system," Applied Power Electronics Conference and Exposition, 2008. APEC 2008. Twenty-Third Annual IEEE, Austin, TX, 2008, pp. 1910-1913.

Q. Zhang, C. Hu, L. Chen, A. Amirahmadi, N. Kutkut, Z. J. Shen, I. Batarseh, "A center point iteration MPPT method with application on the frequency-modulated LLC microinverter," in IEEE Transactions on Power Electronics, vol. 29, no. 3, pp. 1262-1274, March 2014.

Xiaofeng Sun, Yanfeng Shen and Wuying Li, "A novel LLC integrated three-port dc-dc converter for stand-alone PV/battery system," Transportation Electrification Asia-Pacific (ITEC Asia-Pacific), 2014 IEEE Conference and Expo, Beijing, 2014, pp. 1-6.

L. Chen, A. Amirahmadi, Q. Zhang, N. Kutkut and I. Batarseh, "Design and implementation of three-phase two-stage grid-connected module integrated converter," in IEEE Transactions on Power Electronics, vol. 29, no. 8, pp. 3881-3892, Aug. 2014.

T. Jiang, Q. Lin, J. Zhang and Y. Wang, "A novel ZVS and ZCS three-port LLC resonant converter for renewable energy systems," 2014 IEEE Energy Conversion Congress and Exposition (ECCE), Pittsburgh, PA, 2014, pp. 2296-2302.

H. D. Gui, Z. Zhang, X. F. He and Y. F. Liu, "A high voltage-gain LLC micro-converter with high efficiency in wide input range for PV applications," 2014 IEEE Applied Power Electronics Conference and Exposition - APEC 2014, Fort Worth, TX, 2014, pp. 637-642.

K. Jin, X. Ruan, M. Yang, M. Xu, "A novel hybrid fuel cell power system," Power Electronics Specialists Conference, 2006. PESC '06. 37th IEEE, Jeju, 2006, pp. 1-7.

K. Jin and X. Ruan, "Hybrid full-bridge three-level LLC resonant converter-a novel dc-dc converter suitable for fuel-cell power system," in IEEE Transactions on Industrial Electronics, vol. 53, no. 5, pp. 1492-1503, Oct. 2006.

W. Chen, Y. Gu and Z. Lu, "A novel three level full bridge resonant dc-dc converter suitable for high power wide range input applications," APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition, Anaheim, CA, USA, 2007, pp. 373-379.

Koulin Wu Qianhong Chen and Ke Jin Xinbo Ruan, "Integrated magnetic for hybrid full-bridge three-level LLC resonant converter," Electrical Machines and Systems, 2008. ICEMS 2008. International Conference on, Wuhan, 2008, pp. 1937-1941.

F. Canales, T. H. Li and D. Aggeler, "Novel modulation method of a three-level isolated full-bridge LLC resonant dc-dc converter for wide-output voltage application," Power Electronics and Motion Control Conference (EPE/PEMC), 2012 15th International, Novi Sad, 2012, pp. DS2b.11-1-DS2b.11-7.

F. Jin, F. Liu, X. Ruan and X. Meng, "Multi-phase multi-level LLC resonant converter with low voltage stress on the primary-side switches," 2014 IEEE Energy Conversion Congress and Exposition (ECCE), Pittsburgh, PA, 2014, pp. 4704-4710.

H. Haga and F. Kurokawa, "A novel modulation method of the full bridge three-level LLC resonant converter for battery charger of electrical vehicles," 2015 IEEE Energy Conversion Congress and Exposition (ECCE), Montreal, QC, 2015, pp. 5498-5504.

H. Haga, H. Maruta and F. Kurokawa, " Analysis of Voltage Gain Tolerance due to the Resonant Circuit Variation of LLC Resonant Converter," in International Journal of Renewable Energy Research, Vol. 6, No.4, 2016

R. L. Steigerwald, “A comparison of half-bridge resonant converter topologies”, IEEE Transactions on Power Electronics, vol. 3, no. 2, pp. 174-182, Apr. 1988.

The SCAT page in Keisoku Giken web site, http://www.keisoku.co.jp/en/products/power/scat.html, last visited:18 December 2016

DOI: http://dx.doi.org/10.1234/ijrer.v7i1.5925

DOI (PDF): http://dx.doi.org/10.1234/ijrer.v7i1.5925.g7009


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