# MULTILEVEL INVERTER FOR GRID-CONNECTED PHOTOVOLTAIC SYSTEMS

## Keywords:

Maximum power point tracking, Boost converter, Photovoltaic, Grid, Multilevel, Fuzzy logic## Abstract

In the last years, the increasing interest in substituting the conventional huge, centralized power generation systems with distributed renewable energy sources has gained more attention; especially the photovoltaic (PV) distributed energy sources due to their various advantages and benefits. Besides, it becomes quite possible to produce a nearly sinusoidal output voltage waveform that satisfies the grid connection criteria by the use of multilevel voltage source inverters at the grid level. These types of inverters have known an important development that offers more advantages in comparison to their counterparts topologies where the produced ac output voltage is made up of several levels of voltages with lower THD content. In this context, a new power conversion structure is applied to the grid-connected photovoltaic systems where the three-phase three-level neutral point clamped (NPC) multilevel inverter is used. The modeling and the control of the grid-connected PV power system are investigated and each component of the system is presented and discussed in detail. The effectiveness of the proposed structure is checked with the obtained simulation results for the whole system using MATLAB/SIMULINK.

## References

(1) G. Tsantopoulos, G. Arabatzis, S. Tampakis, Public attitudes towards photovoltaic developments: Case study from Greece, Energy Policy., 71, pp. 94–106 (2014).

(2) J.A. Hernandez, D. Velasco, C.L. Trujillo, Analysis of the effect of the implementation of photovoltaic systems like option of distributed generation in Colombia, Renew. Sust Energy Rev., 15, pp. 2290–2298 (2011).

(3) Chen H, et al.: Progress in electrical energy storage system: A critical review, Progress in Natural Science, 10, pp. 291–312 (2009).

(4) J. Alonso-Martinez, J. Eloy-Garcia, S. Arnaltes, Direct power control of grid-connected PV systems with three-level NPC inverter, Sol. Energy, 84, pp. 1175–1186 (2010).

(5) H. Boumaaraf, A. Talha, O. Bouhali, A three-phase NPC grid-connected inverter for photovoltaic applications using neural network MPPT, Renew. Sust Energy Rev., 49, pp. 1171-1179 (2015).

(6) S.B. Kjaer, J. Pedersen, F. Blaabjerg, A review of single-phase grid-connected inverters for photovoltaic modules, IEEE Trans. Ind. Appl., 41, pp. 518–523 (2005).

(7) C. Garrido-Alzar, Algorithm for extraction of solar cell parameters from I-V curve using double exponential model, Renew. Energ., 10, pp. 125-128 (1997).

(8) M. Hejri, H. Mokhtari, M. R. Azizian, M. Ghandhari, L. Soder, On the parameter extraction of a five-parameter double-diode model of photovoltaic cells and modules, IEEE J. Photovolt., 4, 3, pp. 915–923 (2014).

(9) K. Sundareswaran, P. Sankar, P. Nayak, MPPT of PV systems under partially shaded conditions through a colony of flashing fireflies, IEEE Trans. Energy Convers., 29, pp. 463–472 (2014).

(10) G. Saravana Ilango, P. Srinivasa Rao, A. Karthikeyan, C. Nagamani, Single-stage sine-wave inverter for an autonomous operation of solar photovoltaic energy conversion system, Renew. Energy, 35, pp. 275–282 (2010).

(11) H. Fathabadi, Novel high-efficiency dc/dc boost converter for using in photovoltaic systems, Sol. Energy, 125, pp. 22–31 (2016).

(12) A. Robert, H, Turton, T., Casten, Energy efficiency, sustainability, and economic growth, Energy, 32, pp. 634–648 (2007).

(13) H. Boumaaraf, A. Talha, O. Bouhali, Maximum power point tracking using neural networks control for grid-connected photovoltaic system, 4th International Conference on Power Engineering, Energy and Electrical Drives, POWERENG 2013, Istanbul, Turkey, 13-17 May 2013.

(14) A. Panda, M.K. Pathak, Fuzzy intelligent controller for the maximum power point tracking of a photovoltaic module at varying atmospheric conditions; J. Energy Techno. Policy, 2, pp. 18–27 (2011).

(15) B.A. Alajmi, K.H. Ahmed, S.J. Finney, B.W. Williams, Fuzzy-logic-control approach of a modified hill-climbing method for a maximum power point in microgrid standalone photovoltaic system, IEEE Trans. Power Electron., 26, pp. 1022–1030 (2011).

(16) K. Loukil, H.Abbes, H. Abida, M. Abid, A.Toumi, Design and implementation of reconfigurable MPPT fuzzy controller for photovoltaic systems, Ain Shams Engin. Journal, 11, 2, pp. 319–328 (2020).

(17) A. El Khateb, N. Abd Rahim, J. Selvaraj, M. Nasir Uddin, Fuzzy-Logic-Controller-Based SEPIC Converter for Maximum Power Point Tracking, IEEE Trans. Ind. Appl., 50, pp. 2349–2358 (2014).

(18) A. Laib, F. Krim, B. Talbi, H. Feroura, A. Belaout, Hardware implementation of fuzzy maximum power point tracking through sliding mode current control for photovoltaic systems, Rev. Roum. Sci. Techn.– Électrotechn. et Énerg., 66, 2, pp. 91–96 (2021).

(19) S. Thamizharasan, J. Baskaran, S. Ramkumar, S. Jeevananthan, Cross-switched multilevel inverter using auxiliary reverse-connected voltage sources, IET Power Electr, 7, pp. 1519–1526 (2014).

(20) S. Alepuz, S. Busquets-Monge, J. Bordonau, J. Gago, D. Gonzalez, J. Balcells, Interfacing renewable energy sources to the utility grid using a three-level inverter, IEEE Trans. on Ind. Electron., 53, pp. 1504–1511 (2006).

(21) J. Ebrahimi, E. Babaei, G.B. Gharehpetian, A new multilevel converter topology with a reduced number of power electronic components, IEEE Trans. Ind. Elect., 59, pp. 655–667 (2010).

(22) A. Talha, H. Boumaaraf, O. Bouhali, Evaluation of maximum power point tracking methods for photovoltaic systems, Archives of Control Sciences, 21, pp. 151–165 (2011).

(23) D.W. Kang, B.K. Lee, J.H. Jeon, T.J. Kim, D.S. Hyun, A symmetric carrier technique of CRPWM for voltage balance method of flying capacitor multilevel inverter, IEEE Trans. on Ind. Electron., 52, pp. 879–888 (2005).

(24) B. Xiao, L. Hang, J. Mei, C. Riley, L.M. Tolbert, B. Ozpineci, Modular cascaded H-bridge multilevel PV inverter with distributed MPPT for grid-connected application, IEEE Trans. on Ind. Appl., 51, 1722–1731 (2015).

(25) A. Talha, Etude de différentes cascades de l'onduleur a sept niveaux a structure NPC. Application a la conduite d'une machine synchrone a aimants permanents, 2004, Thèse de Doctorat, Ecole Nationale Polytechnique, Alger, Algérie.

(26) L. Tolbert, F.Z. Peng, T.G. Habetler, Multilevel PWM methods at low modulation indices, IEEE Trans. on Power Electron., 15, pp. 719–725 (2000).

(27) F. Blaabjerg, R. Teodorescu, M. Liserre, V. Timbus Adrian, Overview of control and grid synchronization for distributed power generation systems, IEEE Trans. Power Electron., 53, pp. 1398–1409 (2006).

(28) O. Aouchenni, R. Babouri, K. Ghedamsi, D. Aouzellag, Wind farm based on doubly fed induction generator entirely interfaced with power grid through a multilevel inverter, Rev. Roum. Sci. Techn.– Électrotechn. et Énerg. 62, 2, pp. 170–174 (2017).

(29) M. Dali, J. Belhadj, X. Roboam, Hybrid solar-wind system with battery storage operating in gride connected and standalone mode: control and energy management-experimental investigation, Energy, 35, pp. 2587–2595 (2010).