Voltage Control and Load Sharing in a DC Islanded Microgrid Based on Disturbance Observer

Document Type: Research Paper

Authors

1 Dept. of Engineering Shahrekord University Shahrekord, Iran amiri@stu.sku.ac.ir

2 Shahrekord University

3 SRTTU Control Department of Electrical Engineering Faculty, Shahid Rajaee Teacher Training University, Tehran, Iran

10.22061/jecei.2019.5471.225

Abstract

Increasing DC loads along with DC nature of distributed energy resources (DERs) raises interest to DC microgrids. Conventional droop/non-droop power-sharing in microgrids suffers from load dependent voltage deviation, slow transient response, and requires the parameters of the loads, system and DERs connection status. In this paper, a new nonlinear decentralized back-stepping control strategy for voltage control and load sharing of DC islanded microgrids is proposed. The proposed method is robust against the load variations and uncertainty in microgrid parameters and has excellent dynamic and steady-state performance under different operating conditions. The major purpose of the proposed controller is to improve the transient performance of MG with load variations and constant power loads (CPLs). The local controller regulates the terminal voltage of DC-DC converter regarding the local quantities without needs to additional data of other system components. For simplicity, the proposed method is simulated with PSIM software on a DC microgrid with two DGs. Different scenarios are studied to present the performance of the proposed method under different operating conditions. The results indicate the capability of the proposed method for voltage control and load sharing in DC microgrids.

Graphical Abstract

Voltage Control and Load Sharing in a DC Islanded Microgrid Based on Disturbance Observer

Keywords

Main Subjects


[1] A. Emadi, S. S. Williamson, and A. Khaligh, “Power electronics intensive solutions for advanced electric, hybrid electric, and fuel cell vehicular power systems,” IEEE Transactions on Power Electronics, vol. 21, no. 3, pp. 567-577, May 2006.   

[2] T. Dragičević, X. Lu, J. C. Vasquez, and J. M. Guerrero, “DC microgrids—part ii: A review of power architectures, applications, and standardization issues,” IEEE Transactions on Power Electronics, vol. 31, no. 5, pp. 3528-3549, May 2016.   

[3] Y. W. Li and C.-N. Kao, “An accurate power control strategy for power-electronics-interfaced distributed generation units operating in a low-voltage multibus microgrid,” IEEE Transactions on Power Electronics, vol. 24, no. 12, pp. 2977– 2988, Dec. 2009. 

[4] A. Banerji, D. Sen, A.K. Bera, D. Ray, D. Paul, A. Bhakat, and S.K. Biswas, “Microgrid: A review,” in Proc. IEEE Global Humanitarian Technology Conference: South Asia Satellite, GHTC-SAS, pp. 27-35, Aug. 2013. 

 [5] T. Dragicevic, J. C. Vasquez, J. M. Guerrero, and D. Skrlec, “Advanced LVDC electrical power architectures and microgrids: A step toward a new generation of power distribution networks,” IEEE Electrification Magazine, vol. 2, no. 1, pp. 54–65, March 2014.   

 [6] T. Dragičević, X. Lu, J. C. Vasquez, and J. M. Guerrero, “DC microgrids—part i: A review of control strategies and stabilization techniques,” IEEE Transactions on Power Electronics, vol. 31, no. 7, pp. 4876-4891, July 2016.

[7] T. Dragičević, J. M. Guerrero, J. C. Vasquez, and D. Škrlec, “Supervisory control of an adaptive-droop regulated dc microgrid with battery management capability,” IEEE Transactions on Power Electronics, vol. 29, no. 2, pp. 695-706, Feb. 2014. 

[8] Bonfiglio, M. Brignone, F. Delfino, and R. Procopio, “Optimal control and operation of grid-connected photovoltaic production units for voltage support in medium-voltage networks,” IEEE Transactions on Sustainable Energy, vol. 5, no. 1, pp. 254–263, Jan. 2014.

[9] T. Vandoorn, B. Meersman, L. Degroote, B. Renders, and L. Vandevelde, “A control strategy for islanded microgrids with dc-link voltage control,” IEEE Transactions on Power Delivery, vol. 26, no. 2, pp. 703–713, Apr. 2011.

[10] M. Tucci, S. Riverso, J. C. Vasquez, J. M. Guerrero, and G. FerrariTrecate, “A decentralized scalable approach to voltage control of DC islanded microgrids,” IEEE Transactions on Control Systems Technology, vol. 24, no. 6, pp. 1965-1979, Nov. 2016.     

 [11] S. Adhikari, Y. Tang, and P. Wang, “Secondary control for DC microgrids: A review,” in Proc. 2016 Asian Conference on Energy, Power and Transportation Electrification (ACEPT), pp. 1-6, 2016.

[12] M. Tucci, S. Riverso, J. C. Vasquez, J. M. Guerrero, and G. FerrariTrecate, “A decentralized scalable approach to voltage control of dc islanded microgrids,” IEEE Transactions on Control Systems Technology, vol. 24, no. 6, pp. 1965-1979, Nov. 2016.   

[13] Z. J. Qian, O. A. Rahman, H. A. Atrash, and I. Batarseh, “Modeling and control of three-port DC/DC converter interface for satellite applications,” IEEE Transactions on Power Electronics, vol. 25, no. 3, pp. 637-649, 2010.

[14] Y. Yin, J. Liu, S. Vazquez, L. Wu and L. G. Franquelo, "Disturbance observer based second order sliding mode control for DC-DC buck converters," IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, Beijing, pp. 7117-7122, 2017.

[15] Y. H. Xie, R. Ghaemi, J. Sun, and J. S. Freudenberg, “Implicit model predictive control of a full bridge DC-DC converter,” IEEE Transactions on Power Electronics, vol. 24, no. 12, pp. 2704-2713, 2009.

[16] M. Sitbon, S. Schacham, and A. Kuperman, “Disturbance observer-based voltage regulation of current-mode-boostconverter-interfaced photovoltaic generator,” IEEE Transactions on Industrial Electronics, vol. 62, no. 9, pp. 57765785, Sept. 2015.

[17] Z. Wang, S. Li, J. Wang, and Q. Li, “Generalized proportional integral observer based backstepping control for DC-DC buck converters with mismatched disturbances,” in Proc. IEEE International Conference on Industrial Technology (ICIT), pp. 1783-1789, 2016.

[18] C. Wang, X. Li, L. Gu, and Y. W. Li, “A nonlinear-disturbanceobserver-based DC-bus voltage control for a hybrid AC/DC microgrid,” IEEE Transactions on Power Electronics, vol. 29, no. 11, pp. 6162-6177, Nov. 2014.

[19] J. Wang, S. Li, J. Yang, B. Wu, and Q. Li, “Extended state observer-based sliding mode control for PWM-based DC-DC buck power converter systems with mismatched disturbances," IET Control Theory & Applications, vol. 9, no. 4, pp. 579-586, 2 26 2015.

[20] B. Wu, J. Yang, J. X. Wang, and S. H. Li, “Extended state observer based control for DC-DC buck converters subject to mismatched disturbances,” in Proc. IEEE Chinese Control Conference, pp. 8080-8085, 2014.

[21] H. Y. Cui, J. Yang, and S. H. Li, “Nonlinear disturbance rejection control for a buck-boost converter with load uncertainties,” in Proc. IEEE Chinese Control Conference, pp. 3788-3793, 2014.

[22] R. Ghosh and G. Narayanan, “Generalized feedforward control of single-phase PWM rectifiers using disturbance observers,” IEEE Transactions on Industrial Electronics, vol. 54, no. 2, pp. 984-993, 2007. [23] V. Venkatasubramanian, H. Schattler, and J. Zaborszky, “Fast time-varying phasor analysis in the balanced three-phase large electric power system,” IEEE Transactions on Automatic Control , vol. 40, no. 11, pp. 1975-1982, Nov. 1995. 29.

[24] H. Akagi, E. H. Watanabe, and M. Aredes, Instantaneous Power Theory and Applications to Power Conditioning, New Jersey, USA: John Wiley & Sons, IEEE Press series on Power Engineering, 2007, [online] Available: http://unisite.ir/khuelec/wp-content/uploads/Akaqi-H.-Watanabe-E.H.-Aredes-M.-Instantaneous-Power-Theory-and-Applicationsto-Power-Conditioning-2007400s.pdf

[25] H. Sun, S. Li, J. Yang, and W. X. Zheng, “Global output regulation for strict-feedback nonlinear systems with mismatched nonvanishing disturbances,” International Journal of Robust and Nonlinear Control, vol. 25 , no. 15, pp. 2631-2645, Oct. 2015.

[26] J. B. Diaz and F. T. Metcalf, “An analytic proof of Young’s inequality,” Mathematical Association of America, vol. 77, no. 6, pp. 603-609, Jul. 1970.

[27] H. K. Khalil, Nonlinear Systems. Prentice Hall, Upper Saddle River, New Jersey, Third edition, 2002. [28] L. Meng, Q. Shafiee, G. F. Trecate, H. Karimi, D. Fulwani, X. Lu, and J. M. Guerrero, “Review on control of DC microgrids and multiple microgrid clusters,” IEEE Journal of Emerging and
Selected Topics in Power Electronics, vol. 5, no. 3, pp. 928-948, Sept. 2017.

[29] L. Meng, Q. Shafiee, G. F. Trecate, H. Karimi, D. Fulwani, X. Lu, and J. M. Guerrero, “Review on control of DC microgrids and multiple microgrid clusters,” IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 5, no. 3, pp. 928-948, Sept. 2017.

[30] A. Khorsandi, M. Ashourloo, and H. Mokhtari, “A decentralized control method for a low-voltage dc microgrid,” IEEE Transactions on Energy Conversion, vol. 29, no. 4, pp. 793–801, 2014.

[31] J. A. Solsona, S. G. Jorge, and C. A. Busada, “Nonlinear control of a buck converter which feeds a constant power load,” IEEE Transactions on Power Electronics, vol. 30, no. 12, pp. 71937201, Dec. 2015. [32] M. M. Mardani, N. Vafamand, M. H. Khooban, and T. Dragiče, “Design of quadratic d-stable fuzzy controller for DC microgrids with multiple CPLs,” IEEE Transactions on Industrial Electronics, vol. 66, no. 6, pp. 4805-4812, June 2019.

[33] X. Xu, Q. Liu, C. Zhang, and Z. Zeng, “Prescribed performance controller design for DC converter system with constant power loads in DC microgrid,” IEEE Transactions on Systems, Man, and Cybernetics: Systems, (Early Access) DOI: 10.1109/TSMC.2018.2850523.