Fuzzy logic based controller for optimization of voltage unbalance compensation in an autonomous electric microgrid

Document Type : Original Article


Department of Electrical Engineering, Faculty of Electrical and Computer Engineering, Technical and Vocational University (TVU), Tehran, Iran


Recently, there has been an increasing utilization of distributed generators (DGs) in electric power systems not only to supply the demand power of the grid but also to enhance the power quality. In this paper, a new control scheme is proposed for optimization of voltage unbalance compensation in an autonomous microgrid. Adaptive fuzzy PI controller (AFPIC) is applied to a voltage compensation loop which modifies the droop control based inverter reference voltage. Virtual impedance loop is used to enhance the operation of droop control. Voltage unbalance factor (VUF) is calculated by positive and negative sequence components of the output voltage and compared with the maximum threshold. Second-order generalized integrator (SOGI) is used to extract the voltage positive and negative sequence. In the proposed method, microgrid has the dynamic potential of decreasing the VUF below the standard value in all kinds of load conditions while the conventional methods are designed only for a specific load operating point. Proper voltage regulation is also satisfied by back to back embedded voltage and current controllers. A sample microgrid is analyzed in presence of single phase unbalanced load and Matlab simulation results are given to show the effectiveness of the proposed controller.


Chandak and P. K. Rout, "The implementation framework of a microgrid: A review," International Journal of Energy Research, vol. 45, no. 3, pp. 3523-3547, 2021.
A. Jirdehi, V. S. Tabar, S. Ghassemzadeh, and S. Tohidi, "Different aspects of microgrid management: A comprehensive review," Journal of Energy Storage, vol. 30, p. 101457, 2020.
Hemmati, B. Mohammadi-Ivatloo, M. Abapour, and A. Anvari-Moghaddam, "Optimal chance-constrained scheduling of reconfigurable microgrids considering islanding operation constraints," IEEE Systems Journal, vol. 14, no. 4, pp. 5340-5349, 2020.
Bouaicha, E. Craparo, H. Dallagi, and S. Nejim, "Dynamic optimal management of a hybrid microgrid based on weather forecasts," Turkish Journal of Electrical Engineering & Computer Sciences, vol. 28, no. 4, pp. 2060-2076, 2020.
A. HOSSAM-ELDIN, A. A. MANSOUR, M. EL-GAMAL, and K. H. YOUSSEF, "Power quality improvement of smart microgrids using EMS-based fuzzy controlled UPQC," Turkish Journal of Electrical Engineering & Computer Sciences, vol. 27, no. 2, pp. 1181-1197, 2019.
Thomas, G. D’Hoop, O. Deblecker, K. N. Genikomsakis, and C. S. Ioakimidis, "An integrated tool for optimal energy scheduling and power quality improvement of a microgrid under multiple demand response schemes," Applied Energy, vol. 260, p. 114314, 2020.
Xu et al., "Peer-to-Peer Multienergy and Communication Resource Trading for Interconnected Microgrids Microgrids," IEEE Transactions on Industrial Informatics, vol. 17, no. 4, pp. 2522-2533, 2020.
González, A. J. Calderón, and J. M. Portalo, "Innovative multi-layered architecture for heterogeneous automation and monitoring systems: Application case of a photovoltaic smart microgrid," Sustainability, vol. 13, no. 4, p. 2234, 2021.
Aghanoori, M. A. Masoum, A. Abu-Siada, and S. Islam, "Enhancement of microgrid operation by considering the cascaded impact of communication delay on system stability and power management," International Journal of Electrical Power & Energy Systems, vol. 120, p. 105964, 2020.
De Brabandere, B. Bolsens, J. Van den Keybus, A. Woyte, J. Driesen, and R. Belmans, "A voltage and frequency droop control method for parallel inverters," IEEE Transactions on power electronics, vol. 22, no. 4, pp. 1107-1115, 2007.
B. Tayab, M. A. B. Roslan, L. J. Hwai, and M. Kashif, "A review of droop control techniques for microgrid," Renewable and Sustainable Energy Reviews, vol. 76, pp. 717-727, 2017.
C. Chandorkar, D. M. Divan, and R. Adapa, "Control of parallel connected inverters in standalone AC supply systems," IEEE transactions on industry applications, vol. 29, no. 1, pp. 136-143, 1993.
Katiraei and M. R. Iravani, "Power management strategies for a microgrid with multiple distributed generation units," IEEE transactions on power systems, vol. 21, no. 4, pp. 1821-1831, 2006.
M. Guerrero, L. G. De Vicuna, J. Matas, M. Castilla, and J. Miret, "A wireless controller to enhance dynamic performance of parallel inverters in distributed generation systems," IEEE Transactions on power electronics, vol. 19, no. 5, pp. 1205-1213, 2004.
Li and Y. W. Li, "Power management of inverter interfaced autonomous microgrid based on virtual frequency-voltage frame," IEEE Transactions on Smart Grid, vol. 2, no. 1, pp. 30-40, 2011.
J. Chiang, C. Yen, and K. Chang, "A multimodule parallelable series-connected PWM voltage regulator," IEEE Transactions on Industrial Electronics, vol. 48, no. 3, pp. 506-516, 2001.
Moussa, A. Shahin, J.-P. Martin, B. Nahid-Mobarakeh, S. Pierfederici, and N. Moubayed, "Harmonic power sharing with voltage distortion compensation of droop controlled islanded microgrids," IEEE Transactions on Smart Grid, vol. 9, no. 5, pp. 5335-5347, 2017.
S. Munir, Y. W. Li, and H. Tian, "Residential distribution system harmonic compensation using priority driven droop controller," CPSS Transactions on Power Electronics and Applications, vol. 5, no. 3, pp. 213-223, 2020.
Peng, Z. Shuai, X. Liu, Z. Li, J. M. Guerrero, and Z. J. Shen, "Modeling and stability analysis of inverter-based microgrid under harmonic conditions," IEEE Transactions on Smart Grid, vol. 11, no. 2, pp. 1330-1342, 2019.
T. Cheng, C.-A. Chen, T.-L. Lee, and S.-Y. Kuo, "A cooperative imbalance compensation method for distributed-generation interface converters," IEEE Transactions on Industry Applications, vol. 45, no. 2, pp. 805-815, 2009.
Savaghebi, A. Jalilian, J. C. Vasquez, and J. M. Guerrero, "Autonomous voltage unbalance compensation in an islanded droop-controlled microgrid," IEEE Transactions on Industrial Electronics, vol. 60, no. 4, pp. 1390-1402, 2012.
Wang, F. Blaabjerg, and Z. Chen, "An improved design of virtual output impedance loop for droop-controlled parallel three-phase voltage source inverters," in 2012 IEEE Energy Conversion Congress and Exposition (ECCE), 2012, pp. 2466-2473: IEEE.
Wang, L. Xu, and B. W. Williams, "Control of DFIG-based wind farms for network unbalance compensation," in 2008 IEEE Power Electronics Specialists Conference, 2008, pp. 113-119: IEEE.
Rezaei and S. Afsharnia, "Cooperative voltage balancing in islanded microgrid with single-phase loads," in 2011 International Conference on Electrical and Control Engineering, 2011, pp. 5804-5808: IEEE.
Hongbing, Z. Xing, L. Shengyong, and Y. Shuying, "Research on control strategies for distributed inverters in low voltage micro-grids," in The 2nd International Symposium on Power Electronics for Distributed Generation Systems, 2010, pp. 748-752: IEEE.
Hamzeh, H. Karimi, and H. Mokhtari, "A new control strategy for a multi-bus MV microgrid under unbalanced conditions," IEEE Transactions on Power Systems, vol. 27, no. 4, pp. 2225-2232, 2012.
Savaghebi, A. Jalilian, J. C. Vasquez, and J. M. Guerrero, "Secondary control scheme for voltage unbalance compensation in an islanded droop-controlled microgrid," IEEE Transactions on Smart Grid, vol. 3, no. 2, pp. 797-807, 2012.
Liu, T. Wu, Z. Liu, and J. Liu, "A small-AC-signal injection-based decentralized secondary frequency control for droop-controlled islanded microgrids," IEEE Transactions on Power Electronics, vol. 35, no. 11, pp. 11634-11651, 2020.
D. Pham and H.-H. Lee, "Effective coordinated virtual impedance control for accurate power sharing in islanded microgrid," IEEE Transactions on Industrial Electronics, vol. 68, no. 3, pp. 2279-2288, 2020.
Tangsunantham and C. Pirak, "Voltage unbalance measurement in three-phase smart meter applied to AMI systems," in 2013 10th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, 2013, pp. 1-5: IEEE.
Rodriguez, A. V. Timbus, R. Teodorescu, M. Liserre, and F. Blaabjerg, "Flexible active power control of distributed power generation systems during grid faults," IEEE transactions on industrial electronics, vol. 54, no. 5, pp. 2583-2592, 2007.
Dong, Q. Yang, X. Fang, and W. Ruan, "Adaptive optimal fuzzy logic based energy management in multi-energy microgrid considering operational uncertainties," Applied Soft Computing, vol. 98, p. 106882, 2021.