A Novel Photovoltaic Power Harvesting System Using a Transformerless H6 Single-Phase Inverter with Improved Grid Current Quality

- Journal title : Journal of Power Electronics
- Volume 16, Issue 2, 2016, pp.654-665
- Publisher : The Korean Institute of Power Electronics
- DOI : 10.6113/JPE.2016.16.2.654

Title & Authors

A Novel Photovoltaic Power Harvesting System Using a Transformerless H6 Single-Phase Inverter with Improved Grid Current Quality

Radhika, A.; Shunmugalatha, A.;

Radhika, A.; Shunmugalatha, A.;

Abstract

The pumping of electric power from photovoltaic (PV) farms is normally carried out using transformers, which require heavy mounting structures and are thus costly, less efficient, and bulky. Therefore, transformerless schemes are developed for the injection of power into the grid. Compared with the H4 inverter topology, the H6 topology is a better choice for pumping PV power into the grid because of the reduced common mode current. This paper presents how the perturb and observe (P&O) algorithm for maximum power point tracking (MPPT) can be implemented in the H6 inverter topology along with the improved sinusoidal current injected to the grid at unity power factor with the average current mode control technique. On the basis of the P&O MPPT algorithm, a power reference for the present insolation level is first calculated. Maintaining this power reference and referring to the AC sine wave of bus bars, a sinusoidal current at unity power factor is injected to the grid. The proportional integral (PI) controller and fuzzy logic controller (FLC) are designed and implemented. The FLC outperforms the PI controller in terms of conversion efficiency and injected power quality. A simulation in the MATLAB/SIMULINK environment is carried out. An experimental prototype is built to validate the proposed idea. The dynamic and steady-state performances of the FLC controller are found to be better than those of the PI controller. The results are presented in this paper.

Keywords

Active balancing;Electric vehicle;Rechargeable battery;Switching converter;Transformer;

Language

English

References

1.

D. J. Arent, A. Wise1, and R. Gelman, “The status and prospects of renewable energy for combating global warming”, Elseiver Energy Economics, Vol. 33, No. 4, pp. 584-593, Jul. 2011

2.

F. Blaabjerg, Z. Chen, and S. B. Kjaer, “Power electronics as efficient interface in dispersed power generation systems,” IEEE Trans. Power Electron., Vol. 19, No. 5, pp. 1184-1194, Sep. 2014.

3.

L. Zhang, K. Sun, Y. Xing, and M. Xing, “H6 transformerless full-bridge PV grid-tied inverters,” IEEE Trans. Power Electron., Vol. 29, No. 3, pp. 1229-1238, Mar. 2014.

4.

W. Yu, J.-S. Lai, H. Qian, C. Hutchens, J. Zhang, G. Lisi, A. Djabbari, G. Smith, and T. Hegarty, “High-efficiency MOSFET inverter with H6-type configuration for photovoltaic nonisolated AC-module applications,” IEEE Trans. Power Electron., Vol. 26, No. 4, pp. 1253-1260, Apr. 2011.

5.

B. Ji, J. Wang, and J. Zhao, “High-efficiency single-phase transformerless PV H6 inverter with hybrid modulation method,” IEEE Trans. Ind. Electron., Vol. 60, No. 5, pp. 2104 -2115, Oct. 2012.

6.

R. Gonzalez, E. Gubia, J. Lopez, and L. Marroyo, “Transformerless single-phase multilevel-based photovoltaic inverter,” IEEE Trans. Ind. Electron., Vol. 55, No. 7, pp. 2694-2702, Jul. 2008.

7.

H. Patel and V. Agarwal, “A single-stage single-phase transformer-less doubly grounded grid-connected PV interface,” IEEE Trans. Energy Convers., Vol. 24, No. 1, pp. 93-101, Feb. 2009.

8.

S. Aeaujo, P. Zacharias, and R. Mallwitz, “Highly efficient single-phase transformerless inverters for grid-connected photovoltaic systems,” IEEE Trans. Ind. Electron., Vol. 57, No. 9, pp. 3118-3128, Aug. 2010.

9.

H. Xiao and S. Xie, “Transformerless split-inductor neutral point clamped three-level PV grid-connected inverter,” IEEE Trans. Power Electron., Vol. 27, No. 4, pp. 1799-1808, Feb. 2012.

10.

M. C. Cavalcanti, K. C. de Oliveira, A. M. de Farias, F. A. S. Neves, G. M. S. Azevedo, and F. C. Camboim, “Modulation techniques to eliminate leakage currents in transformerless three-phase photovoltaic systems,” IEEE Trans. Ind. Electron., Vol. 57, No. 4, pp. 1360-1368, Mar. 2010.

11.

O. Lopez, F. D. Freijedo, A. G. Yepes, F. Comesana, J. Malvar, R. Teodorescu, and J. Doval-Gandoy, “Eliminating ground current in a transformerless photovoltaic application,” IEEE Trans. Energy Convers., Vol. 25, No. 1, pp. 140-147, Mar. 2010.

12.

H. Xiao and S. Xie, “Leakage current analytical model and application in single-phase transformerless photovoltaic grid-connected inverter,” IEEE Trans. Electromagnetic Compat., Vol. 52, No. 4, pp. 902-913, Nov. 2010.

13.

B. Yang, W. Li, Y. Gu, W. Cui, and X. He, “Improved transformerless inverter with common-mode leakage current elimination for a photovoltaic grid-connected power system,” IEEE Trans. Power Electron., Vol. 27, No. 2, pp. 752-762, Feb. 2012.

14.

M. A. G. de Brito, L. Galotto, and L. P. Sampaio, “Evaluation of the main MPPT techniques for photovoltaic applications,” IEEE Trans. Ind. Electron., Vol. 60, No. 3, pp. 1156-1167, Mar. 2013.

15.

A. R. Reisi, M. H. Moradi, and S. Jamasb, “Classification and comparison of maximum power point tracking techniques for photovoltaic system: A review,” Elseiver, Renewable and Sustainable Energy Reviews, Vol. 19, pp.433-443, Mar. 2013.

16.

N. Femia, G. Petrone, G. Spagnuolo, and M. Vitelli, “Optimization of perturb and observe maximum power point tracking method,” IEEE Trans. Power Electron., Vol. 20, No. 4, pp. 963-973, Jul. 2005.

17.

S. K. Kollimalla, and M. K. Mishra, “A novel adaptive P&O MPPT algorithm considering sudden changes in the irradiance,” IEEE Trans. Energy Convers., Vol. 29, No. 3, pp. 602-610, Sep. 2014.

18.

X. Gao, S. Li, and R. Gong, “Maximum power point tracking control strategies with variable weather parameters for photovoltaic generation systems,” Elseiver, Solar Energy, Vol. 93, pp. 357-367, Jul. 2013.