A Modified Double-Integral-Sliding-Mode-Controller for a Microgrid System With Uncertainty
Recently infiltration of large scale of microgrid systems into the power grid is recorded. Among these systems, photovoltaic (PV) based microgrid systems are more in demand due to its renewable, pollution free properties and abundantly available fuel. Grid integration of this microgrid system again enhanced its energy efficiency. But, dynamics of this PV based microgrid system is highly nonlinear and uncertain in nature. It suffers from parametric uncertainties. This kind of system can’t be controlled properly by conventional linear controllers. Sliding mode controller (SMC) is capable of controlling this kind of system with ease. However, SMC suffers from its inherent chattering introduction in the system output waveform. To reduce the chattering from the output waveform, there is requirement of some modification in the existing SMC structure dynamics. This paper presents an extended state observer based double integral sliding mode controller (DISMC) for this studied system. By using DISMC, the chattering magnitude is diminished greatly. Parameter uncertainties of the system lead to some unknown control states. These unknown states are identified by the state observer. Therefore, the proposed controller is more efficient in reference tracking, disturbance rejection and robust stability. To test the efficacies of the proposed controller, results of the studied system with this controller are compared with that of H∞ controller.
Erdem, Z. B. 2010. The contribution of renewable resources in meeting Turkey’s energy-related challenges. Renewable and Sustainable Energy Reviews, 14(9): 2710–2722, doi: 10.1016/j.rser.2010.07.003.
Jana, J., Saha, H., and Bhattacharya, K. D. 2017. A review of inverter topologies for single-phase grid-connected photovoltaic systems. Renewable and Sustainable Energy Reviews, 72: 1256–1270, doi: 10.1016/j.rser.2016.10.049.
Kjaer, S. B., Pedersen, J. K., and Blaabjerg, F. 2005. A review of single-phase grid-connected inverters for photovoltaic modules. IEEE transactions on industry applications, 41(5): 1292–1306, doi: 10.1109/TIA.2005.853371.
Eltawil, M. A., and Zhao, Z. 2010. Grid-connected photovoltaic power systems: Technical and potential problems—A review. Renewable and sustainable energy reviews, 14(1): 112–129, doi: 10.1016/j.rser.2009. 07.015.
Zue, A. O., and Chandra, A. 2009. State feedback linearization control of a grid connected photovoltaic interface with MPPT. In 2009 IEEE Electrical Power & Energy Conference (EPEC): 1–6, doi: 10.1109/EPEC.2009.5420870.
Kim, I. S. 2007. Robust maximum power point tracker using sliding mode controller for the three-phase grid-connected photovoltaic system. Solar Energy, 81(3): 405–414, doi: 10.1016/j.solener.2006.04.005.
Mahmud, M. A., Pota, H. R., Hossain, M. J., and Roy, N. K. 2013. Robust partial feedback linearizing stabilization scheme for three-phase grid-connected photovoltaic systems. IEEE Journal of photovoltaics, 4(1): 423–431, doi: 10.1109/JPHOTOV.2013.2281721.
Hassaine, L., OLias, E., Quintero, J., and Salas, V. 2014. Overview of power inverter topologies and control structures for grid connected photovoltaic systems. Renewable and Sustainable Energy Reviews, 30: 796–807, doi: 10.1016/j.rser.2013.11.005.
Rasool, A., Ahmad, F., & Šabanović, A. 2017. Voltage source converter control under unbalanced grid voltage conditions.XXVI International Conference on Information, Communication and Automation Technologies (ICAT): 1–6, doi: 10.1109/ICAT.2017.8171643.
Tan, S. C., Lai, Y. M., and Chi, K. T. 2008. General design issues of sliding-mode controllers in DC–DC converters. IEEE Transactions on Industrial Electronics, 55(3): 1160–1174, doi: 10.1109/TIE.2007. 909058.
Kim, I. S. 2006. Sliding mode controller for the single-phase grid-connected photovoltaic system. Applied Energy, 83(10): 1101–1115, doi: 10.1016/j.apenergy.2005.11.004.
Hace, A., Jezernik, K., and Sabanovic, A. 2007. SMC with disturbance observer for a linear belt drive. IEEE Transactions on Industrial Electronics, 54(6): 3402–3412, doi: 10.1109/TIE.2007.906130.
Chowdhury, M. A., and Mahmud, M. A. 2014. Characteristics evaluation of a H∞ loop-shaping controller for a single-phase PV system.IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC): 1–6, doi: 10.1109/APPEEC.2014.7066115.
Baranwal, M., Askarian, A., Salapaka, S., and Salapaka, M. 2018. A distributed architecture for robust and optimal control of DC microgrids. IEEE Transactions on Industrial Electronics, 66(4): 3082–3092, doi: 10.1109/TIE.2018.2840506.
Wang, Y., Wu, Q., Yang, R., Tao, G., and Liu, Z. 2018. H∞ current damping control of DFIG based wind farm for sub-synchronous control interaction mitigation. International Journal of Electrical Power & Energy Systems, 98: 509–519, doi. 10.1016/j.ijepes.2017.12.003.
Zhang, X. P., Rehtanz, C., and Pal, B. 2012. Flexible AC transmission systems: modelling and control. Springer Science & Business Media, doi: 10.1007/978-3-642-28241-6.
Toloue, S. F., Kamali, S. H., and Moallem, M. 2019. Multivariable sliding-mode extremum seeking PI tuning for current control of a PMSM. IET Electric Power Applications, 14(3): 348–356, doi: 10.1049/iet-epa.2019.0033.
Pradhan, S. S., R. Pradhan and B.Subudhi. 2019. Design and Analysis of an H∞ Controller for a Single Phase Grid Connected Photovoltaic System with Parametric Uncertainties. Second International Conference on Advanced Computational and Communication Paradigms (ICACCP), doi. 10.1109/ICACCP.2019.8882898.
Pradhan, R. and B. Subudhi. 2012. A new digital double integral sliding mode maximum power point tracker for photovoltaic power generation application. IEEE Third International Conference on Sustainable Energy Technologies (ICSET): 183–188, doi. 10.1109/ICSET.2012.6357395.