中国电气工程学报（英文） ›› 2018, Vol. 4 ›› Issue (2): 36-42.

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  • 出版日期:2018-06-25 发布日期:2019-10-31

Two-Stage Transformerless Dual-Buck PV Grid-Connected Inverters with High Efficiency

Li Zhang1,2,*, Fengkai Jiang1, DeweiXu2, Kai Sun3, Yongqiang Hao1, Tao Zhang1   

  1. 1. College of Energy and Electrical Engineering, Hohai University, Nanjing 211100, China;
    2. Department of Electrical and Computer Engineering, Ryerson University, Toronto M5B 2K3, Canada;
    3. Department of Electrical and Engineering, Tsinghua University, Beijing 10084, China
  • Online:2018-06-25 Published:2019-10-31
  • Contact: *, E-mail: zhanglinuaa@hhu.edu.cn.
  • About author:Li Zhang (S'11-AG3M'13) received the B.E. and Ph.D. degrees in electrical engineering from Nanjing University of Aeronautics and Astronautics(NUAA), Nanjing, China, in 2007, and 2012, respectively. He joined the Faculty of Electrical Engineering, Hohai University, Nanjing, China, in 2014, where he is currently an Associate Professor. From Oct. 2012 to Sep. 2014, he was a Post-Doctoral Research Fellow with the Department of Electrical Engineering, Tsinghua University, Beijing, China. From Jul. to Aug. 2014, he was a Visiting Scholar at Department of Energy Technology, Aalborg University, Denmark. From Oct. 2016 to Oct. 2017, he was a Visiting Professor at Department of Electrical and Computer Engineering, Ryerson University, Canada. His current research interests include topology, control of DC-AC converter and distributed generation technology. Dr. Zhang was a recipient of the IEEE Transactions on Power Electronics Outstanding Reviewer Award in 2014. Fengkai Jiang was born in Jiangsu Province, China, in 1994. He received the B.E. degree in electrical engineering from Jiangsu University of Science and Technology(JUST), Zhenjiang, China, in 2017. He is currently working toward the M.S. degree in power electronics and power drives at Hohai University(HHU). His main research interests include topology and control of DC-AC convertersDewei (David) Xu (S'99–M'01) received the B.Sc., M.A.Sc., and Ph.D. degrees in electrical engineering from Tsinghua University, Beijing, China, in 1996, 1998, and 2001 respectively. Since 2001, he has been working with Ryerson University, Toronto, ON, Canada, where he is currently a full professor. His research interests include renewable energy systems, high power converters, electric motor drives and advanced digital control for power electronics. Kai Sun (M'12-SM'16) received the B.E., M.E., and Ph.D. degrees in electrical engineering from Tsinghua University, Beijing, China, in 2000, 2002, and 2006, respectively. He joined the faculty of Electrical Engineering, Tsinghua University, in 2006, where he is currently an Associate Professor. From Sep 2009 to Aug 2010, he was a Visiting Scholar at Department of Energy Technology, Aalborg University, Aalborg, Denmark. From Jan to Aug 2017, he was a Visiting Professor at Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada. His current research interests include power electronics for renewable generation systems, microgrids, and energy internet. Dr. Sun is a member of IEEE Power Electronics Society Sustainable Energy Systems Technical Committee, a member of IEEE Power Electronics Society Power and Control Core Technologies Committee, and a member of IEEE Industrial Electronics Society Renewable Energy Systems Technical Committee. Dr. Sun serves as an Associate Editor for IEEE Transactions on Power Electronics, IEEE Journal of Emerging and Selected Topics in Power Electronics, and Journal of Power Electronics. Dr. Sun served as the TPC Vice Chair of IEEE ECCE2017 and IEEE ECCE-Asia2017. He was a recipient of Delta Young Scholar Award in 2013, and Youth Award of China Power Supply Society (CPSS) in 2017. Yongqiang Hao was born in Shanxi Province, China, in 1993. He received the B.E. degree in agricultural electrification and automation from Inner Mongolia Agricultural University (IMAU), Hohhot, China, in 2016. He is currently working toward the M.S. degree in electrical engineering and power drives at Hohai University(HHU). His main research interests include topology and control of dc-ac converters. Yongqiang Hao was born in Shanxi Province, China, in 1993. He received the B.E. degree in agricultural electrification and automation from Inner Mongolia Agricultural University (IMAU), Hohhot, China, in 2016. He is currently working toward the M.S. degree in electrical engineering and power drives at Hohai University(HHU). His main research interests include topology and control of dc-ac converters.
  • Supported by:
    This work was supported in part by the National Natural Science Foundation of China under Grant 51677054, and in part by the 13th Six Talent Peaks Project in Jiangsu Province under Grant XNY-008.

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Abstract: A semi-two-stage common-ground-type transformerless dual-buck-based grid-connected inverter is proposed in this paper. The common-ground-type topology can eliminate common mode (CM) leakage current by connecting the negative terminal of the photovoltaic(PV) directly to the neutral point of the grid, which bypasses the PV array’s stray capacitance. The dual-buck-based topology guarantees increased robustness since the dc-link cannot be short-circuited by a shoot-through event. The semi-two-stage topology features multi-level characteristic, which has a lower forward-voltage drop and smaller dv/dt. Compared with the conventional two-stage inverter, the proposed topology achieves higher efficiency and higher reliability. Experimental results of a 1.5kW prototype show that the proposed inverter is able to achieve high efficiency and low leakage currents.

Key words: Common mode current, photovoltaic, semi-two-stage inverter, transformerless inverter, common-ground-type inverter