A Decentralized Control Method Based on Virtual Frequency-Voltage Frame for Accurate Active and Reactive Powers Sharing in Microgrids

Subject Areas : Renewable energy

Nader Kazemi-Esfeh ¹ , Mehdi Baharizadeh ²

1 - Department of Electrical Engineering- Khomeinishahr Branch, Islamic Azad University, Isfahan, Iran
2 - Department of Electrical Engineering- Khomeinishahr Branch, Islamic Azad University, Isfahan, Iran

Received: 2022-02-19 Accepted : 2022-05-01 Published : 2023-11-22

Keywords: Microgrid, Droop characteristics, Islanded operation mode, Power sharing,

Abstract :

In the islanded operation mode of microgrids, active and reactive powers sharing among sources is required. In order to provide this and based on decentralized approach, droop characteristics are used. The conventional droop characteristics of active power-frequency (P-ω) and reactive power-voltage (Q-V) are based on the assumption of inductive output impedance of sources. Since the dominant inductive output impedances are not provided, especially in low voltage microgrids, the virtual frequency-voltage frame droop characteristics, which include active power-virtual frequency (P-ωʹ) and reactive power-virtual voltage (Q-Vʹ) droop characteristics have been considered by researchers. By employing these droops, local property of both the virtual frequency and the virtual voltage leads to active power sharing error as well as reactive power sharing error. In addition, required small intended variation range of both virtual frequency and virtual voltage, results in big power sharing errors. In order to eliminate active and reactive power sharing errors, a decentralized control method is proposed in this paper. In the proposed method, instead of virtual frequency and virtual voltage of their terminal, sources droop virtual frequency and virtual voltage of point of common coupling (PCC) in order to a common parameter becomes in charge of active power generation as well as a common parameter becomes responsible for reactive power generation. Accordingly, the power sharing errors are resolved. Realization method of these droop characteristics will be explained in details. In order to confirm the performance of the proposed control method, simulation results of a test microgrid in PSIM software are presented.

References:

[1] G. Shahgholian, "A brief review on microgrids: Operation, applications, modeling, and control", International Transactions on Electrical Energy Systems, vol. 31, no. 6, Article Number: e12885, June 2021 (doi: 10.1002/2050-7038.12885).

[2] M. Baharizadeh, M.S. Golsorkhi, M. Shahparasti, M. Savaghebi, "A two-layer control scheme based on P – V droop characteristic for accurate power sharing and voltage regulation in dc microgrids", IEEE Trans. on Smart Grid, vol. 12, no. 4, pp. 2776-2787, July 2021 (doi: 10.1109/TSG.2021.3060074).

[3] S. Gorji, S. Zamanian, M. Moazzami, “Techno-economic and environmental base approach for optimal energy management of microgrids using crow search algorithm”, Journal of Intelligent Procedures in Electrical Technology, vol. 11, no. 43, pp. 49-68, Oct. 2020 (dor: 20.1001.1.23223871.1399.11.43.4.7).

[4] H. Han, X. Hou, J. Yang, J. Wu, M. Su, J.M. Guerrero, "Review of power sharing control strategies for islanding operation of ac microgrids", IEEE Trans. on Smart Grid, vol. 7, no. 1, pp. 200-215, Jan. 2016 (doi: 10.1109/TSG.2015.2434849).

[5] J.M. Guerrero, J.C. Vasquez, J. Matas, L.G. Vicuna, M. Castilla, "Hierarchical control of droop-controlled ac and dc microgrids- A general approach toward standardization", IEEE Trans. on Industrial Electronics, vol. 58, no. 1, pp. 158-172, Jan. 2011 (doi: 10.1109/TIE.2010.2066534).

[6] A. Khaledian, "High-reliability electric power generation system for aircraft based on generators smart droop control method", Journal of Intelligent Procedures in Electrical Technology, vol. 13, no. 52, pp. 19-32, June 2023 (dor: 20.1001.1.23223871.1402.14.53.2.6).

[7] Y. Li, Y.W. Li, "Power management of inverter interfaced autonomous microgrid based on virtual frequency-voltage frame", IEEE Trans. on Smart Grid, vol. 2, no. 1, pp. 30-40, March 2011 (doi: 10.1155/­201­3/­816525).

[8] J. He, Y.W. Li, “Analysis, design, and implementation of virtual impedance for power electronics interfaced distributed generation”, IEEE Trans. on Industry Applications, vol. 47, no. 6, pp. 2525-2538, Nov./Dec. 2011 (doi: 10.1109/TIA.2011.2168592).

[9] J.M. Guerrero, J. Matas, L.G. Vicuna, M. Castilla, J. Miret, "Decentralized control for parallel operation of distributed generation inverters using resistive output impedance", IEEE Trans. on Industrial Electronics, vol. 54, no. 2, pp. 994-1004, April 2007 (doi: 10.1109/TIE.2007.892621).

[10] D.C. Raj, D.N. Gaonkar, J.M. Guerrero, “Power sharing control strategy of parallel inverters in ac microgrid using improved reverse droop control”, International Journal of Power Electronics, vol. 11, no. 1, pp. 116-137, 2020 (doi: 10.1504/IJPELEC.2020.103953).

[11] M. Kamali, B. Fani, G. Shahgholian, G.B. Gharehpetian, M. Shafiee, "Harmonic compensation and micro-grid voltage and frequency control based on power proportional distribution with adaptive virtual impedance method", Journal of Intelligent Procedures in Electrical Technology, vol. 14, no. 53, pp. 33-60, June 2023 (dor: 20.1001.1.23223871.1402.14.53.3.7).

[12] Y. Li, Y.W. Li, "Virtual frequency-voltage frame control of inverter based low voltage microgrid", Proceeding of the IEEE/EPEC, pp. 1-6, Montreal, QC, Canada, Oct. 2009 (doi: 10.1109/EPEC.200­9.542­09­7­3).

[13] Y. Han, H. Li, P. Shen, E.A.A. Coelho, J.M. Guerrero, "Review of active and reactive power sharing strategies in hierarchical controlled microgrids", IEEE Trans. on Power Electronics, vol. 32, no. 3, pp. 2427-2451, March 2017 (doi: 10.1109/TPEL.2016.2569597).

[14] J. Zhou, P. Cheng, "A modified  droop control for accurate reactive power sharing in distributed generation microgrid", IEEE Trans. on Industrial Application, vol. 55, no. 4, pp. 4100-4109, July/Aug. 2019 (doi: 10.1109/TIA.2019.2903093).

[15] Y. Khayat, Q. Shafiee, R. Heydari, M. Naderi, T. Dragičević, J.W. Simpson-Porco, F. Dörfler, M. Fathi, F. Blaabjerg, J.M. Guerrero, H. Bevrani, “On the secondary control architectures of ac microgrids: An overview", IEEE Trans. on Power Electronics, vol. 35, no. 6, pp. 6482-6500, June 2020 (doi: 10.1109/TP­EL.201­9.2951694).

[16] A. Micallef, M. Apap, C. Spiteri-Staines, J.M. Guerrero, J.C. Vasquez, "Reactive power sharing and voltage harmonic distortion compensation of droop controlled single phase islanded microgrids", IEEE Trans. on Smart Grid, vol. 5, no. 3, pp. 1149-1158, May 2014 (doi: 10.1109/TSG.2013.2291912).

[17] Y.W. Li, C.N. Kao, “An accurate power control strategy for power-electronics-interfaced distributed generation units operating in a low-voltage multibus microgrid”, IEEE Trans. on Power Electronics, vol. 24, no. 12, pp. 2977-2988, Dec. 2009 (doi: 10.1109/TPEL.2009.2022828).

[18] M. Baharizadeh, H.R. Karshenas, J.M. Guerrero, ''An improved power control strategy for hybrid ac-dc microgrids'', International Journal of Electrical Power and Energy Systems, vol. 95, pp. 364-373, Feb. 2018 (doi: 10.1016/j.ijepes.2017.08.036).

[19] A. Mohammed, S.S. Refaat, S. Bayhan, H. Abu-Rub, "AC microgrid control and management strategies: Evaluation and review", IEEE Power Electronics Magazine, vol. 6, no. 2, pp. 18-31, June 2019 (doi: 10.11­0­9/MP­EL.2019.2910292).

[20] S. Leitner, M. Yazdanian, A. Mehrizi-Sani, A. Muetze, "Small-signal stability analysis of an inverter-based microgrid with internal model-based controllers", IEEE Trans. on Smart Grid, vol. 9, no. 5, pp. 5393-5402, Sept. 2018 (doi: 10.1109/TSG.2017.2688481).

[21] N. Pogaku, M. Prodanovic, T.C. Green, "Modeling, analysis and testing of autonomous operation of an inverter-based microgrid", IEEE Trans. on Power Electronics, vol. 22, no. 2, pp. 613-625, March 2007 (doi: 10.1109/TPEL.2006.890003).