Review of Active Synchronization for Renewable Powered Microgrid


  • Nur Aisyah Mohd Yusof
  • Zaipatimah Ali





Active synchronization, Microgrid, Passive synchronization, Reconnection, Synchronization


Microgrid can operate in dual mode; grid-connected and islanded mode. In order to seamless transfer from islanded microgrid to grid connected mode, it is necessary to voltage, frequency and phase of microgrid to synchronize with main grid to prevent severe consequence. However, microgrid has to be controlled in a coordinated way to achieve a synchronization. This paper present a review on the existing active synchronization approach with their control strategies. There are three approach for grid-connected synchronization; active synchronization, passive synchronization and open transition transfer. However, only active synchronization approach provides the reliable reconnection for microgrid. Active synchronization approach associates with control structures and control strategies. There are three control structures of microgrid under active synchronization; centralized, decentralized and distributed and three control strategies available in the literature which are phase locked loop (PLL), droop control, and frequency locked loop (FLL). The most applicable control strategy for active synchronization is phase locked loop because of its simplicity, robustness, and effectiveness in various main grid condition. Furthermore, between three control structures of active synchronization, decentralized control is becoming more favorable by the researches based on its advantages over the other structures.




[1] N. W. A. Lidula and A. D. Rajapakse, “Microgrids research: A review of experimental microgrids and test systems,†Renew. Sustain. Energy Rev., vol. 15, no. 1, pp. 186–202, Jan. 2011.

[2] S. A. K. David G. Hart, “PAC World magazine : Microgrids Integrating renewable energy sources - (RES) to improve reliability.†[Online]. Available: [Accessed: 06-Dec-2017].

[3] G. Li et al., “R[1] G. Li et al., ‘Risk Analysis for Distribution Systems in the Northeast U.S. Under Wind Storms,’ IEEE Trans. Power Syst., vol. 29, no. 2, pp. 889–898, Mar. 2014.isk Analysis for Distribution Systems in the Northeast U.S. Under Wind Storms,†IEEE Trans. Power Syst., vol. 29, no. 2, pp. 889–898, Mar. 2014.

[4] C. Chen, J. Wang, F. Qiu, and D. Zhao, “Resilient Distribution System by Microgrids Formation after Natural Disasters,†IEEE Trans. Smart Grid, vol. 7, no. 2, pp. 958–966, 2016.

[5] B. Zhao, X. Dong, and J. Bornemann, “Service Restoration for a Renewable-Powered Microgrid in Unscheduled Island Mode,†IEEE Trans. Smart Grid, vol. 6, no. 3, pp. 1128–1136, May 2015.

[6] Di Shi, R. Sharma, and Yanzhu Ye, “Adaptive control of distributed generation for microgrid islanding,†in IEEE PES ISGT Europe 2013, 2013, pp. 1–5.

[7] S. Soman, S. Tom, P. Thomas, and J. George, “Forced islanding and restoration scheme to prevent blackout for improving power system security,†Proc. 2015 IEEE Innov. Smart Grid Technol. - Asia, ISGT ASIA 2015, 2016.

[8] M. H. Moradi, M. Eskandari, and S. M. Hosseinian, “Cooperative control strategy of energy storage systems and micro sources for stabilizing microgrids in different operation modes,†Int. J. Electr. Power Energy Syst., vol. 78, pp. 390–400, Jun. 2016.

[9] M. N. Arafat, A. Elrayyah, and Y. Sozer, “An Effective Smooth Transition Control Strategy Using Droop-Based Synchronization for Parallel Inverters,†IEEE Trans. Ind. Appl., vol. 51, no. 3, pp. 2443–2454, May 2015.

[10] Institute of Electrical and Electronics Engineers. and IEEE-SA Standards Board., IEEE guide for design, operation, and integration of distributed resource island systems with electric power systems. Institute of Electrical and Electronics Engineers, 2011.

[11] J. M. Guerrero, J. C. Vasquez, J. Matas, L. G. De Vicuña, and M. Castilla, “Hierarchical control of droop-controlled AC and DC microgrids - A general approach toward standardization,†IEEE Trans. Ind. Electron., vol. 58, no. 1, pp. 158–172, 2011.

[12] J. C. Vasquez, J. M. Guerrero, J. Miret, M. Castilla, and L. G. De Vicuña, “Hierarchical Control of Intelligent Microgrids,†IEEE Ind. Electron. Mag., no. December 2010, pp. 23–29, 2010.

[13] D. E. Olivares et al., “Trends in microgrid control,†IEEE Trans. Smart Grid, vol. 5, no. 4, pp. 1905–1919, 2014.

[14] J. M. Guerrero, M. Chandorkar, T. Lee, and P. C. Loh, “Advanced Control Architectures for Intelligent Microgrids; Part I: Decentralized and Hierarchical Control,†Ind. Electron. IEEE Trans., vol. 60, no. 4, pp. 1254–1262, 2013.

[15] O. Palizban and K. Kauhaniemi, “Hierarchical control structure in microgrids with distributed generation: Island and grid-connected mode,†Renew. Sustain. Energy Rev., vol. 44, pp. 797–813, 2015.

[16] J. Dudiak, Z. Conka, and M. Kolcun, “Hierarchical control of microgrid with renewable energy sources and energy storage,†Proc. 8th Int. Sci. Symp. Electr. Power Eng. Elektro-Energetika 2015, vol. 16, no. 18, pp. 2–6, 2015.

[17] A. Bidram and A. Davoudi, “Hierarchical structure of microgrids control system,†IEEE Trans. Smart Grid, vol. 3, no. 4, pp. 1963–1976, 2012.

[18] “What is Grid Synchronization | IGI Global.†[Online]. Available: [Accessed: 18-Jan-2018].

[19] D. L. Ransom, “Get in step with synchronization,†IEEE Trans. Ind. Appl., vol. 50, no. 6, pp. 4210–4215, 2014.

[20] “ANSI C84.1 ELECTRIC POWER SYSTEMS AND EQUIPMENT - VOLTAGE RANGES | Power Quality In Electrical Systems.†[Online]. Available: [Accessed: 17-Jan-2018].

[21] P. IEEE Standards Coordinating Committee 21 (Fuel Cells, IEEE-SA Standards Board., and Institute of Electrical and Electronics Engineers., IEEE standard for interconnecting distributed resources with electric power systems. Institute of Electrical and Electronics Engineers, 2003.

[22] N. W. A. Lidula and A. D. Rajapakse, “Voltage balancing and synchronization of microgrids with highly unbalanced loads,†Renew. Sustain. Energy Rev., vol. 31, pp. 907–920, 2014.

[23] Y. Yoldaş, A. Önen, S. M. Muyeen, A. V. Vasilakos, and İ. Alan, “Enhancing smart grid with microgrids: Challenges and opportunities,†Renew. Sustain. Energy Rev., vol. 72, no. October 2016, pp. 205–214, 2017.

[24] A. Sharma, D. Srinivasan, and A. Trivedi, “A Decentralized Multiagent System Approach for Service Restoration Using DG Islanding,†Smart Grid, IEEE Trans., vol. PP, no. 99, p. 1, 2015.

[25] S. Schuler, W. Zhou, U. Münz, and F. Allgöwer, “Controller Structure Design for Decentralized Control of Coupled Higher Order Subsystems,†2010.

[26] Y. LI and F. NEJABATKHAH, “Overview of control, integration and energy management of microgrids,†J. Mod. Power Syst. Clean Energy, vol. 2, no. 3, pp. 212–222, Sep. 2014.

[27] M. Yazdanian and A. Mehrizi-Sani, “Distributed control techniques in microgrids,†IEEE Trans. Smart Grid, vol. 5, no. 6, pp. 2901–2909, 2014.

[28] W. Su and J. Wang, “Energy Management Systems in Microgrid Operations,†Electr. J., vol. 25, no. 8, pp. 45–60, Oct. 2012.

[29] Y. Sun, C. Zhong, X. Hou, J. Yang, H. Han, and J. M. Guerrero, “Distributed cooperative synchronization strategy for multi-bus microgrids,†Int. J. Electr. Power Energy Syst., vol. 86, pp. 18–28, Mar. 2017.

[30] D. Shi et al., “A Distributed Cooperative Control Framework for Synchronized Reconnection of a Multi-Bus Microgrid,†IEEE Trans. Smart Grid, vol. 3053, no. c, pp. 1–10, 2017.

[31] G.-C. Hsieh and J. C. Hung, “Phase-locked loop techniques- A survey,†IEEE Trans. Ind. Electron., vol. 43, no. 6, pp. 609–615, 1996.

[32] S. Golestan, M. Monfared, and F. D. Freijedo, “Design-Oriented Study of Advanced Synchronous Reference Frame Phase-Locked Loops,†IEEE Trans. Power Electron., vol. 28, no. 2, pp. 765–778, Feb. 2013.

[33] M. Monfared and S. Golestan, “Control strategies for single-phase grid integration of small-scale renewable energy sources: A review,†Renew. Sustain. Energy Rev., vol. 16, no. 7, pp. 4982–4993, 2012.

[34] S. Golestan, M. Monfared, F. D. Freijedo, J. M. Guerrero, and S. Member, “Advantages and Challenges of a Type-3 PLL,†vol. 28, no. 11, pp. 4985–4997, 2013.

[35] F. Tang, J. M. Guerrero, J. C. Vasquez, D. Wu, and L. Meng, “Distributed Active Synchronization Strategy for Microgrid Seamless Reconnection to the Grid Under Unbalance and Harmonic Distortion,†IEEE Trans. Smart Grid, vol. 6, no. 6, pp. 2757–2769, Nov. 2015.

[36] N. Jaalam, N. A. Rahim, A. H. A. Bakar, C. K. Tan, and A. M. A. Haidar, “A comprehensive review of synchronization methods for grid-connected converters of renewable energy source,†Renewable and Sustainable Energy Reviews. 2016.

[37] M. Haripriya and C. Vasanthanayaki, “CAN based grid synchronisation technique of a micro grid with Renewable source,†in 2017 International Conference on Innovations in Green Energy and Healthcare Technologies (IGEHT), 2017, pp. 1–4.

[38] A. Bellini, S. Bifaretti, and F. Giannini, “A Robust Synchronization Method for Centralized Microgrids,†IEEE Trans. Ind. Appl., vol. 51, no. 2, pp. 1602–1609, Mar. 2015.

[39] Y. Han, M. Xia, X. Hong, and M. Ye, “A smooth transition control strategy for microgrid operation modes,†Energy Procedia, vol. 61, pp. 760–766, 2014.

[40] M. Rizo, F. Huerta, E. Bueno, and M. Liserre, “A synchronization technique for microgrid reclosing after islanding operation,†IECON Proc. (Industrial Electron. Conf., pp. 5596–5601, 2012.

[41] M. Surprenant, I. Hiskens, and G. Venkataramanan, “Phase locked loop control of inverters in a microgrid,†2011 IEEE Energy Convers. Congr. Expo., pp. 667–672, 2011.

[42] M. J. Far, “Simulation For Synchronization Of A Micro-Grid With Three-Phase Systems,†Ijstr.Org, vol. 4, no. 09, 2015.

[43] Y. Li, D. M. Vilathgamuwa, and P. C. Loh, “Design, Analysis, and Real-Time Testing of a Controller for Multibus Microgrid System,†IEEE Trans. Power Electron., vol. 19, no. 5, pp. 1195–1204, Sep. 2004.

[44] A. G. Tsikalakis and N. D. Hatziargyriou, “Centralized Control for Optimizing Microgrids Operation,†IEEE Trans. Energy Convers., vol. 23, no. 1, pp. 241–248, Mar. 2008.

[45] C. Jin, M. Gao, X. Lv, and M. Chen, “A seamless transfer strategy of islanded and grid-connected mode switching for microgrid based on droop control,†2012 IEEE Energy Convers. Congr. Expo. ECCE 2012, pp. 969–973, 2012.

[46] Y. Jia, D. Liu, and J. Liu, “A novel seamless transfer method for a microgrid based on droop characteristic adjustment,†Conf. Proc. - 2012 IEEE 7th Int. Power Electron. Motion Control Conf. - ECCE Asia, IPEMC 2012, vol. 1, pp. 362–367, 2012.

[47] A. Micallef, M. Apap, C. Spiteri-Staines, and J. M. Guerrero, “Single-Phase Microgrid with Seamless Transition Capabilities between Modes of Operation,†IEEE Trans. Smart Grid, vol. 6, no. 6, pp. 2736–2745, 2015.

[48] T. L. Vandoorn, B. Meersman, J. D. M. De Kooning, and L. Vandevelde, “Transition from islanded to grid-connected mode of microgrids with voltage-based droop control,†IEEE Trans. Power Syst., vol. 28, no. 3, pp. 2545–2553, 2013.

[49] C. T. Lee, R. P. Jiang, and P. T. Cheng, “A grid synchronization method for droop-controlled distributed energy resource converters,†IEEE Trans. Ind. Appl., vol. 49, no. 2, pp. 954–962, 2013.

[50] C. Cho, J.-H. Jeon, J.-Y. Kim, S. Kwon, K. Park, and S. Kim, “Active Synchronizing Control of a Microgrid,†IEEE Trans. Power Electron., vol. 26, no. 12, pp. 3707–3719, Dec. 2011.

[51] Y. Han, H. Li, P. Shen, E. A. A. Coelho, and J. M. Guerrero, “Review of Active and Reactive Power Sharing Strategies in Hierarchical Controlled Microgrids,†IEEE Trans. Power Electron., vol. 32, no. 3, pp. 2427–2451, 2017.

[52] J. Rocabert, G. M. S. Azevedo, A. Luna, J. M. Guerrero, J. I. Candela, and P. Rodrguez, “Intelligent connection agent for three-phase grid-connected microgrids,†IEEE Trans. Power Electron., vol. 26, no. 10, pp. 2993–3005, 2011.

View Full Article: