A High Efficiency Two-stage Inverter for Photovoltaic Grid-connected Generation Systems

  • Liu, Jiang (Key Laboratory of Education Ministry for Image Processing and Intelligent Control, School of Automation, Huazhong University of Science and Technology) ;
  • Cheng, Shanmei (Key Laboratory of Education Ministry for Image Processing and Intelligent Control, School of Automation, Huazhong University of Science and Technology) ;
  • Shen, Anwen (Key Laboratory of Education Ministry for Image Processing and Intelligent Control, School of Automation, Huazhong University of Science and Technology)
  • Received : 2016.06.15
  • Accepted : 2016.08.09
  • Published : 2017.01.20


Conventional boost-full-bridge and boost-hybrid-bridge two-stage inverters are widely applied in order to adapt to the wide dc input voltage range of photovoltaic arrays. However, the efficiency of the conventional topology is not fully optimized because additional switching losses are generated in the voltage conversion so that the input voltage rises and then falls. Moreover, the electrolytic capacitors in a dc-link lead to a larger volume combined with increases in both weight and cost. This paper proposes a higher efficiency inverter with time-sharing synchronous modulation. The energy transmission paths, wheeling branches and switching losses for the high-frequency switches are optimized so that the overall efficiency is greatly improved. In this paper, a contrastive analysis of the component losses for the conventional and proposed inverter topologies is carried out in MATLAB. Finally, the high-efficiency under different switching frequencies and different input voltages is verified by a 3 kW prototype.


  1. "Global status report 2015 Technical report," Renewable Energy Policy Framework, pp. 1-33, Jun. 2015.
  2. S. Thangaprakash, "Unified MPPT control strategy for Z-Source inverter based photovoltaic power conversion systems," Journal of Power Electronics, Vol. 12, No. 1, pp. 172-180, Jan. 2012.
  3. S. Kouro, J. I. Leon, D. Vinnikov, and L. G. Franquelo, "Grid-connected photovoltaic system: an overiew of recent research and emerging PV converter technology," IEEE Ind. Electron. Mag., Vol. 9, No. 1, pp. 47-61, Mar. 2015.
  4. D. Yang and H. Yin, "Energy conversion efficiency of a novel hybrid solar system for photovoltaic, thermoelectric, and heat utilization," IEEE Trans. Energy Convers., Vol. 26, No. 2, pp. 662-670, Jun. 2011.
  5. Y. Xue, L. Chang, S. B. Kjaer, J. Bordonau, and T. Shimizu, "Topologies of single-phase inverters for small distributed power generators: an overview," IEEE Trans. Power Electron., Vol. 19, No. 5, pp. 1305-1314, Sep. 2004.
  6. S. B. Kjaer, J. K. Pedersen, and F. Blaabjerg, "A review of single-phase grid-connected inverters for photovoltaic modules," IEEE Trans. Ind. Appl., Vol. 41, No. 5, pp. 1292-1306, Sep./Oct. 2005.
  7. H. Xiao, S. Xie, Y. Chen, and R. Huang, "An optimized transformerless photovoltaic grid-connected inverter," IEEE Trans. Ind. Electron., Vol. 58, No. 5, pp. 1887-1895, May 2011.
  8. A. Radhika and A. Shunmugalatha, "A novel photovoltaic power harvesting system using a transformerless H6 single-phase inverter with improved grid current quality," Journal of Power Electronics, Vol. 16, No. 2, pp. 654-665, Mar. 2016.
  9. B. Gu, J. Dominic, J.-S. Lai, C.-L. Chen, T. Labella, and B. Chen, "High reliability and efficiency single-phase transformerless inverter for grid-connected photovoltaic systems," IEEE Trans. Power Electron., Vol. 28, No. 5, pp. 2235-2245, May 2013.
  10. F. Chan and H. Calleja, "Design strategy to optimize the reliability of grid-connected PV systems," IEEE Trans. Ind. Electron., Vol. 56, No. 11, pp. 4465-4472, Nov. 2009.
  11. H. S. Bae, J. H. Park, B. H. Cho, and G. J. Yu, "New MPPT control strategy for two-stage grid-connected photovoltaic power conditioning system," Journal of Power Electronics, Vol. 7, No. 2, pp. 174-180, Apr. 2007.
  12. M. E. S. Ahmed, M. Orabi, and O. M. AdelRahim, "Two-stage micro-grid inverter with high-voltage gain for photovoltaic applications," IET Power Electronics, Vol. 6, No. 9, pp. 1812-1821, Nov. 2013.
  13. Y. J. Lee, Analysis and control of the full bridge based power electronic system using a current reconstruction technique, Ph.D. dissertation, Elect. Eng., Konkuk Univ., Seoul, Korea, 2013.
  14. J.-M. Choe, Y.-J. Lee, Y. Cho, and G.-H. Choe, "A performance comparison of the current feedback schemes with a new single current sensor technique for single-phase full-bridge inverters," Journal of Power Electronics, Vol. 16, No. 2, pp. 621-630, Mar. 2016.
  15. H. Akca and U. S. Selamogullari, "Hybrid switch use for light load efficiency improvement of a power inverter for stand-alone residential renewable energy system," in 15th European conference on Power electronics and Applications, pp. 1-6, Sep. 2013.
  16. B. Yang, W. Li, Y. Zhao, and X. He, "Design and analysis of a grid-connected photovoltaic power system," IEEE Trans. Power Electron., Vol. 25, No. 4, pp. 992-1000, Apr. 2010.
  17. F. J. Vorster, E. E. van Dyk, and A. W. R. Leitch, "Investigation on the I-V characteristics of a high concentration, photovoltaic array," in 29th IEEE Photovoltaic Specialists Conference, pp. 1604-1607, May 2002.
  18. Q. Li and P. Wolfs, "A review of the single phase photovoltaic module integrated converter topologies with three different DC link configurations," IEEE Trans. Power Electron, Vol. 23, No. 3, pp. 1320-1333, May 2008.
  19. W.-J. Cha, K.-T. Kim, Y.-W. Cho, S.-H. Lee, and B.-H. Kwon, "Evaluation and analysis of transformerless photovoltaic inverter topology for efficiency improvement and reduction of leakage current," IET Power Electronics, Vol. 8, No. 2, pp. 255-267, Feb. 2015.
  20. J. W. Kolar, H. Ertl, and F. C. Zach, "How to include the dependency of the RDS(on) of power MOSFETs on the instantaneous value of the drain current into the calculation of the conduction losses of high-frequency three-phase PWM inverters," IEEE Trans. Ind. Electron., Vol. 45 No. 3, pp. 369-375, Jun. 1998.
  21. G. I. Orfanoudakis, S. M. Sharkh, and M. A. Yuratich, "Analysis of DC-Link capacitor losses in three-level neutral point clamped and cascaded H-Bridge voltage source inverters," IEEE International Symposium on Industrial Electronics, pp. 664-669, 2010.
  22. T. Shimizu and S. Iyasu, "A practical iron loss calculation for AC filter inductors used in PWM inverters," IEEE Trans. Ind. Electron., Vol. 56, No. 7, pp. 2600-2609, Jul. 2009.

Cited by

  1. FCS-MPC for a single-phase two-stage grid-connected PV inverter pp.1755-4543, 2019,