Adaptive complex virtual impedance control scheme for accurate reactive power sharing of inverter interfaced autonomous microgrids

Adaptive complex virtual impedance control scheme for accurate reactive power sharing of inverter interfaced autonomous microgrids

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The mismatched feeder impedance of the voltage-sourced converter (VSC) units may result in reactive power sharing error in the islanded microgrids. This study presents a reactive power sharing strategy for single-phase inverter-based microgrids that eliminates the circulating currents and reduces the coupling between real and reactive powers. The proposed controller is based on an adaptive complex virtual impedance that aims to equalise the characteristic output of VSCs. The resistive term regulates the virtual voltage drop using the proposed droop characteristic, while the inductive one controls the phase angle of VSC current and increases the ratio of the microgrid. The proposed strategy does not require a central controller and knowledge of the microgrid lines and loads data and is applicable for the various microgrid topologies. Furthermore, it employs the unidirectional low bandwidth communication link and is robust against the delay and failure of communication channels. The proposed method is implemented using the conventional droop control scheme and presents the medium plug and play capability. Both simulation and experimental case studies using various microgrid topologies are conducted to demonstrate the merits of the proposed scheme.


    1. 1)
      • 1. Guerrero, J., Vasquez, J., Matas, J., et al: ‘Hierarchical control of droop-controlled AC and DC microgrids – a general approach toward standardization’, IEEE Trans. Ind. Electron., 2011, 58, (1), pp. 158172. doi:10.1109/TIE.2010.2066534.
    2. 2)
      • 2. Sadeghkhani, I., Golshan, M.E.H., Guerrero, J.M., et al: ‘A current limiting strategy to improve fault ride-through of inverter interfaced autonomous microgrids’, IEEE Trans. Smart Grid, 2017, 8, (5), pp. 21382148. doi:10.1109/TSG.2016.2517201.
    3. 3)
      • 3. Fani, B., Zandi, F., Karami-Horestani, A.: ‘An enhanced decentralized reactive power sharing strategy for inverter-based microgrid’, Int. J. Electr. Power, 2018, 98, pp. 531542. doi:10.1016/j.ijepes.2017.12.023.
    4. 4)
      • 4. Lasseter, R.H.: ‘Microgrids’. IEEE Power Engineering Society Winter Meeting, New York, NY, USA, January 2002, vol. 1, pp. 305308. doi:10.1109/PESW.2002.985003.
    5. 5)
      • 5. Katiraei, F., Iravani, R., Hatziargyriou, N., et al: ‘Microgrids management’, IEEE Power Energy Mag., 2008, 6, (3), pp. 5465. doi:10.1109/MPE.2008.918702.
    6. 6)
      • 6. IEEE guide for design, operation, and integration of distributed resource island systems with electric power systems’, IEEE Std 15474-2011, 2011, pp. 154. doi:10.1109/IEEESTD.2011.5960751.
    7. 7)
      • 7. Rokrok, E., Golshan, M.E.H.: ‘Adaptive voltage droop scheme for voltage source converters in an islanded multibus microgrid’, IET Gener. Transm. Distrib., 2010, 4, (5), pp. 562578. doi:10.1049/iet-gtd.2009.0146.
    8. 8)
      • 8. He, J., Li, Y.W.: ‘An enhanced microgrid load demand sharing strategy’, IEEE Trans. Power Electron., 2012, 27, (9), pp. 39843995. doi:10.1109/TPEL.2012.2190099.
    9. 9)
      • 9. Li, Y., Li, Y.W.: ‘Power management of inverter interfaced autonomous microgrid based on virtual frequency-voltage frame’, IEEE Trans. Smart Grid, 2011, 2, (1), pp. 3040. doi:10.1109/TSG.2010.2095046.
    10. 10)
      • 10. Zhong, Q.C.: ‘Robust droop controller for accurate proportional load sharing among inverters operated in parallel’, IEEE Trans. Ind. Electron., 2013, 60, (4), pp. 12811290. doi:10.1109/TIE.2011.2146221.
    11. 11)
      • 11. Li, Y.W., Kao, C.N.: ‘An accurate power control strategy for power-electronics-interfaced distributed generation units operating in a low-voltage multibus microgrid’, IEEE Trans. Power Electron., 2009, 24, (12), pp. 29772988. doi:10.1109/TPEL.2009.2022828.
    12. 12)
      • 12. Han, H., Hou, X., Yang, J., et al: ‘Review of power sharing control strategies for islanding operation of AC microgrids’, IEEE Trans. Smart Grid, 2016, 7, (1), pp. 200215. doi:10.1109/TSG.2015.2434849.
    13. 13)
      • 13. IEEE standard for interconnecting distributed resources with electric power systems’, IEEE Std 1547-2003, 2003, pp. 128. doi:10.1109/IEEESTD.2003.94285.
    14. 14)
      • 14. Vieira, J.C.M., Freitas, W., Xu, W., et al: ‘Efficient coordination of ROCOF and frequency relays for distributed generation protection by using the application region’, IEEE Trans. Power Deliv., 2006, 21, (4), pp. 18781884. doi:10.1109/TPWRD.2006.881588.
    15. 15)
      • 15. Mohamed, Y.A.R.I., El-Saadany, E.F.: ‘Adaptive decentralized droop controller to preserve power sharing stability of paralleled inverters in distributed generation microgrids’, IEEE Trans. Power Electron., 2008, 23, (6), pp. 28062816. doi:10.1109/TPEL.2008.2005100.
    16. 16)
      • 16. Wang, X., Li, Y.W., Blaabjerg, F., et al: ‘Virtual-impedance-based control for voltage-source and current-source converters’, IEEE Trans. Power Electron., 2015, 30, (12), pp. 70197037. doi:10.1109/TPEL.2014.2382565.
    17. 17)
      • 17. Sun, Y., Hou, X., Yang, J., et al: ‘New perspectives on droop control in AC microgrid’, IEEE Trans. Ind. Electron., 2017, 64, (7), pp. 57415745. doi:10.1109/TIE.2017.2677328.
    18. 18)
      • 18. Sao, C.K., Lehn, P.W.: ‘Control and power management of converter fed microgrids’, IEEE Trans. Power Syst., 2008, 23, (3), pp. 10881098. doi:10.1109/TPWRS.2008.922232.
    19. 19)
      • 19. Guerrero, J.M., Matas, J., de Vicuna, L.G., et al: ‘Decentralized control for parallel operation of distributed generation inverters using resistive output impedance’, IEEE Trans. Ind. Electron., 2007, 54, (2), pp. 9941004. doi:10.1109/TIE.2007.892621.
    20. 20)
      • 20. Zhu, Y., Zhuo, F., Wang, F., et al: ‘A virtual impedance optimization method for reactive power sharing in networked microgrid’, IEEE Trans. Power Electron., 2016, 31, (4), pp. 28902904. doi:10.1109/TPEL.2015.2450360.
    21. 21)
      • 21. Yao, W., Chen, M., Matas, J., et al: ‘Design and analysis of the droop control method for parallel inverters considering the impact of the complex impedance on the power sharing’, IEEE Trans. Ind. Electron., 2011, 58, (2), pp. 576588. doi:10.1109/TIE.2010.2046001.
    22. 22)
      • 22. Mahmood, H., Michaelson, D., Jiang, J.: ‘Accurate reactive power sharing in an islanded microgrid using adaptive virtual impedances’, IEEE Trans. Power Electron., 2015, 30, (3), pp. 16051617. doi:10.1109/TPEL.2014.2314721.
    23. 23)
      • 23. He, J., Li, Y.W., Guerrero, J.M., et al: ‘An islanding microgrid reactive power sharing scheme enhanced by programmed virtual impedances’. 3rd IEEE Int. Symp. on Power Electronics for Distributed Generation Systems (PEDG), Aalborg, Denmark, June 2012, pp. 229235. doi:10.1109/PEDG.2012.6254006.
    24. 24)
      • 24. Zhu, Y., Zhuo, F., Wang, F., et al: ‘A wireless load sharing strategy for islanded microgrid based on feeder current sensing’, IEEE Trans. Power Electron., 2015, 30, (12), pp. 67066719. doi:10.1109/TPEL.2014.2386851.
    25. 25)
      • 25. Hamzeh, M., Mokhtari, H., Karimi, H.: ‘A decentralized self-adjusting control strategy for reactive power management in an islanded multi-bus MV microgrid’, Can. J. Elect. Comput. E, 2013, 36, (1), pp. 1825. doi:10.1109/CJECE.2013.6544468.
    26. 26)
      • 26. He, J., Li, Y.W.: ‘Analysis, design, and implementation of virtual impedance for power electronics interfaced distributed generation’, IEEE Trans. Ind. Appl., 2011, 47, (6), pp. 25252538. doi:10.1109/TIA.2011.2168592.
    27. 27)
      • 27. Wu, X., Shen, C., Iravani, R.: ‘Feasible range and optimal value of the virtual impedance for droop-based control of microgrids’, IEEE Trans. Smart Grid, 2017, 8, (3), pp. 12421251. doi:10.1109/TSG.2016.2519454.
    28. 28)
      • 28. Zhang, H., Kim, S., Sun, Q., et al: ‘Distributed adaptive virtual impedance control for accurate reactive power sharing based on consensus control in microgrids’, IEEE Trans. Smart Grid, 2017, 8, (4), pp. 17491761. doi:10.1109/TSG.2015.2506760.
    29. 29)
      • 29. Schiffer, J., Seel, T., Raisch, J., et al: ‘Voltage stability and reactive power sharing in inverter-based microgrids with consensus-based distributed voltage control’, IEEE Trans. Control Syst. Technol., 2016, 24, (1), pp. 96109. doi:10.1109/TCST.2015.2420622.
    30. 30)
      • 30. Rocabert, J., Luna, A., Blaabjerg, F., et al: ‘Control of power converters in AC microgrids’, IEEE Trans. Power Electron., 2012, 27, (11), pp. 47344749. doi:10.1109/TPEL.2012.2199334.
    31. 31)
      • 31. Micallef, A., Apap, M., Spiteri-Staines, C., et al: ‘Reactive power sharing and voltage harmonic distortion compensation of droop controlled single phase islanded microgrids’, IEEE Trans. Smart Grid, 2014, 5, (3), pp. 11491158. doi:10.1109/TSG.2013.2291912.
    32. 32)
      • 32. He, J., Li, Y.W., Guerrero, J.M., et al: ‘An islanding microgrid power sharing approach using enhanced virtual impedance control scheme’, IEEE Trans. Power Electron., 2013, 28, (11), pp. 52725282. doi:10.1109/TPEL.2013.2243757.
    33. 33)
      • 33. Zhou, J., Kim, S., Zhang, H., et al: ‘Consensus-based distributed control for accurate reactive, harmonic, and imbalance power sharing in microgrids’, IEEE Trans. Smart Grid, 2018, 9, (4), pp. 24532467. doi:10.1109/TSG.2016.2613143.
    34. 34)
      • 34. Han, H., Liu, Y., Sun, Y., et al: ‘An improved droop control strategy for reactive power sharing in islanded microgrid’, IEEE Trans. Power Electron., 2015, 30, (6), pp. 31333141. doi:10.1109/TPEL.2014.2332181.
    35. 35)
      • 35. Kim, S., Zhang, H., Sun, Q.: ‘Consensus-based improved droop control for suppressing circulating current using adaptive virtual impedance in microgrids’. Chinese Control and Decision Conf. (CCDC), Yinchuan, China, May 2016, pp. 44734478. doi:10.1109/CCDC.2016.7531790.
    36. 36)
      • 36. Meghwani, A., Srivastava, S.C., Chakrabarti, S.: ‘A new protection scheme for DC microgrid using line current derivative’. IEEE Power Energy Society General Meeting, Denver, CO, USA, July 2015, pp. 15. doi:10.1109/PESGM.2015.7286041.
    37. 37)
      • 37. Sadeghkhani, I., Golshan, M.E.H., Mehrizi-Sani, A., et al: ‘Transient monitoring function-based fault detection for inverter-interfaced microgrids’, IEEE Trans. Smart Grid, 2018, 9, (3), pp. 20972107.
    38. 38)
      • 38. Banerji, A., Biswas, S.K., Singh, B.: ‘Enhancing quality of power to sensitive loads with microgrid’, IEEE Trans. Ind. Appl., 2016, 52, (1), pp. 360368. doi:10.1109/TIA.2015.2478884.

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