An Improved Grid Connected Transformerless Inverter with Proportional Resonant Controller
Subject Areas : electrical and computer engineeringJ. Fallah Ardashir 1 , M. Sabahi 2 * , S. H. Hosseini 3 , E. Babaei 4 , G. Gharehpetian 5
1 -
2 -
3 -
4 -
5 -
Keywords: Transformerless inverter leakage current ommon mode voltage proportional resonant controller,
Abstract :
The grid tied PV systems without transformer have some benefits such as low cost, weight and size and also increases the overall efficiency. The galvanic connection between the grid and PV system causes leakage current in the transformerless inverter to flow through parasitic capacitors between the PV system and ground and causes personal safety problems, increases the output harmonic spectrum, and system losses. This paper introduces a modified single phase two stage transformerless inverter for grid connected photovoltaic systems with low leakage current. The neutral of the grid is directly connected to the negative terminal of PV panel that eliminates leakage current without complex control strategy. In this paper, a Proportional Resonant (PR) control strategy is used to control the injected current. The performance of the transformerless inverter is analyzed and its structure has been simulated in PSCAD/EMTDC and the obtained results tested experimentally.
[1] F. Bradaschia, M. C. Cavalcanti, P. E. P. Ferraz, F. A. S. Neves, E. C. dos Santos, and J. H. G. Mda Silva, "Modulation for three-phase transformerless Z-Source inverter to reduce leakage currents in photovoltaic systems," IEEE Trans. on Ind. Electron., vol. 58, no. 12, pp. 5385-5395, Dec. 2011.
[2] M. C. Cavalcanti, A. M. Farias, K. C. Oliveira, F. A. S. Neves, and J. L. Afonso, "Eliminating leakage currents in neutral point clamped inverters for photovoltaic systems," IEEE Trans. on Ind. Electron., vol. 59, no. 1, pp. 435-443, Jan. 2012.
[3] D. Barater, G. Buticchi, A. S. Crinto, G. Franceschini, and E. Lorenzani, "Unipolar PWM strategy for transformerless PV grid-connected converters," IEEE Trans. Power Electron., vol. 27, no. 4, pp. 835-843, Dec. 2012.
[4] Y. Bae and R. Y. Kim, "Suppression of common-mode voltage using a multi central photovoltaic inverter topology with synchronized PWM," IEEE Trans. on Ind. Electron., vol. 61, no. 9, pp. 4722-4733, Sept. 2014.
[5] W. Li, Y. Gu, H. Luo, W. Cui, X. He, and C. Xia, "Topology review and derivation methodology of single phase transformerless photovoltaic inverters for leakage current suppression," IEEE Trans. on Ind. Electron., vol. 62, no. 7, pp. 4737-4551, Jul. 2015.
[6] J. Ji, W. Wu, Y. He, Z. Lin, F. Blaabjerg, and H. Shu-Hung, "A simple differential mode EMI suppressor for the LLCL-filter based single phase grid-tied transformerless inverter," IEEE Trans. on Ind. Electron., vol. 62, no. 7, pp. 4141-4147, Jul. 2015.
[7] N. Vazquez, M. Rosas, C. Hernandez, E. Vazquez, and F. J. Perez-Pinal, "A new common-mode transformerless photovoltaic inverter," IEEE Trans. on Ind. Electron., vol. 62, no. 10, pp. 6381-6391, Oct. 2015.
[8] S. Saridakis, E. Koutroulis, and F. Blaabjerg, "Optimal design of modern transformerless PV inverter topologies," IEEE Trans. Energy Conv., vol. 28, no. 2, pp. 394-404, Jun. 2013.
[9] B. N. Alajmi, K. H. Ahmed, G. P. Adam, and B. W. Williams, "Single-phase single-stage transformerless grid-connected PV system," IEEE Trans. Power Electron., vol. 28, no. 6, pp. 2664-2676, Jun. 2013.
[10] H. Luo, Y. Dong, W. Li, and X. He, "Modular multilevel-clamped multilevel converter (M-MC2) with dual T-Type modules and one diode module," J. of Power Electron., vol. 14, no. 6, pp. 1189-1196, Nov. 2014.
[11] E. S. Sreeraj, K. Chatterjee, and S. Bandyopadhyay, "One-cycle-controlled single-stage single-phase voltage sensorless grid-connected PV system," IEEE Trans. on Ind. Electron., vol. 60, no. 3, pp. 1216-1224, Mar. 2013.
[12] L. C. Breazeale and R. Ayyanar, "A photovoltaic array transformer-less inverter with film capacitors and silicon carbide transistors," IEEE Trans. Power Electron., vol. 30, no. 3, pp. 1297-1305, Mar. 2015.
[13] J. M. Shen, H. L. Jou, and J. C. Wu, "Novel transformerless grid-connected power converter with negative grounding for photovoltaic generation system," IEEE Trans. Power Electron., vol. 27, no. 4, pp. 1818-1829, Apr. 2012.
[14] M. Kazanbas, L. Menezes, and P. Zacharias, "Considerations on grounding possibilities of transformerless grid-connected photovoltaic inverters," in Proc. Energy Conf. and Exhibition, ENERGYCON'12, pp. 9-12, Nov. 2012.
[15] T. Salmi, M. Bouzguenda, A. Gastli, and A. Masmoudi, "A novel transformerless inverter topology without zero-crossing distortion," Int. J. of Renewable Energy Res.,vol. 2, no 1, pp. 140-146, Feb. 2012.
[16] O. Lopez, R. Teodorescu, F. Freijedo, and J. Doval-Gandoy, "Leakage current evaluation of a single-phase transformerless PV inverter connected to the grid," in Proc. IEEE Appl. Power Electron. Conf., pp. 907-912, Anaheim, CA, USA, May 2007.
[17] Y. Wang and R. Li, "Novel high-efficiency three-level stacked-neutral point-clamped grid-tied inverter," IEEE Trans. Ind. Elect., vol. 60, no. 9, pp. 3766-3774, Sep. 2013.
[18] N. Zhang, H. Tang, and C. Yao, "A systematic method for designing a PR controller and active damping of the LCL filter for single-phase grid-connected PV inverters," Energies, vol. 7, no. 6, pp. 3934-3954, Jun. 2014.
[19] D. N. Zmood and D. G. Holmes, "Stationary frame current regulation of PWM inverters with zero steady-state error," IEEE Trans. Power Electron., vol. 18, no. 3, pp. 814-822, May 2003.
[20] S. Lee, H. Kim, K. T. Kwon, and J. M. Kwon, "Single-phase transformerless bi-directional inverter with high efficiency and low leakage current," IET Power Electron., vol. 7, no. 2, pp. 451-458, Feb. 2014.
[21] T. K. S. Freddy, N. A. Rahim, H. Wooi-Ping, and S. C. Hang Wu, "Comparison and analysis of single-phase transformerless grid connected PV inverters," IEEE Trans. Power Electron., vol. 29, no. 6, pp. 5358-5369, Oct. 2014.