Control strategy of DFIG in hybrid micro-grid using sliding mode frequency controller and observer

Control strategy of DFIG in hybrid micro-grid using sliding mode frequency controller and observer

For access to this article, please select a purchase option:

Buy article PDF
(plus tax if applicable)
Buy Knowledge Pack
10 articles for £75.00
(plus taxes if applicable)

IET members benefit from discounts to all IET publications and free access to E&T Magazine. If you are an IET member, log in to your account and the discounts will automatically be applied.

Learn more about IET membership 

Recommend Title Publication to library

You must fill out fields marked with: *

Librarian details
Your details
Why are you recommending this title?
Select reason:
IET Generation, Transmission & Distribution — Recommend this title to your library

Thank you

Your recommendation has been sent to your librarian.

A doubly fed-induction generator (DFIG) has a significant advantage of fast dynamic frequency regulation. However, conventional virtual inertia control (VIC) design only takes frequency into account and may face secondary frequency drop during rotor speed restoration. To solve these problems, the novel decentralised control strategy is proposed for a hybrid micro-grid. Firstly, the load disturbance is considered to enhance control system accuracy, which is estimated by using the state observer based on the dynamic mathematical model. Then, the sliding mode VIC controller is designed by taking advantage of the observed disturbance value and frequency deviation for DFIG output dynamic adjustment according to the conventional frequency control (VIC) model. Furthermore, during DFIG rotor speed restoration, pitch angle control based on the mathematical model is applied for reserve capacity, and a new triggering condition according to the conventional condition is designed, so as to release reserve power at an appropriate time. Finally, the proposed strategy is tested in a typically isolated micro-grid with diesel and DFIG through a simulation and experiment.


    1. 1)
      • 1. Peas, J.A., Moreira, C.L., Madureira, A.G.: ‘Defining control strategies for microgrids islanded operation’, IEEE Trans. Power Syst., 2006, 21, (2), pp. 916924.
    2. 2)
      • 2. Wang, C, Xiao, Z, Wang, S.: ‘Synthetical control and analysis of microgrid’, Autom. Electr. Power Syst., 2008, 32, (7), pp. 98103(in Chinese).
    3. 3)
      • 3. Du, W., Jiang, Q., Chen, J.: ‘Frequency control strategy of distributed generations based on virtual inertia in a microgrid’, Autom. Electr. Power Syst., 2011, 12, (10), pp. 2630(in Chinese).
    4. 4)
      • 4. Singh, S., Verma, R.K., Shakya, A.K., et al: ‘Frequency regulation of micro-grid connected hybrid power system with SMES’, Technol. Econ. Smart Grids Sustain. Energy, 2017, 2, (1), pp. 13.
    5. 5)
      • 5. Singh, S., Singh, M., Chanana, S., et al: ‘Frequency regulation of isolated hybrid wind/diesel, power generation with fuel cell system’, Power Electron. Renew. Energy Syst., 2015, 326, (1), pp. 853862.
    6. 6)
      • 6. Tang, X, Miao, F, Qi, Z, et al: ‘Survey on frequency control of wind power’, Proc. CSEE, 2014, 34, (25), pp. 43044314(in Chinese).
    7. 7)
      • 7. Liu, J, Yao, W, Wen, J., et al: ‘Prospect of technology for large-scale wind farm participating into power grid frequency regulation’, Power Syst. Technol., 2014, 38, (3), pp. 638646(in Chinese).
    8. 8)
      • 8. Li, H., Zhang, X., Wang, Y., et al: ‘Virtual inertia control of DFIG-based wind turbines based on the optimal power tracking’, Proc. CSEE, 2012, 32, (7), pp. 3239(in Chinese).
    9. 9)
      • 9. Keung, P.-K., Li, P., Banakar, H.: ‘Kinetic energy of wind-turbine generators for system frequency support’, IEEE Trans. Power Syst., 2009, 24, (1), pp. 279287.
    10. 10)
      • 10. Arani, M.F.M., El-Saadany, E.F.: ‘Implementing virtual inertia in DFIG-based wind power generation’, IEEE Trans. Power Syst., 2013, 28, (2), pp. 13731384.
    11. 11)
      • 11. Kayikci, M., Milanovic, J.V.: ‘Dynamic contribution of doubly-based wind plants to system frequency disturbances’, IEEE Trans. Power Syst., 2009, 24, (22), pp. 859867.
    12. 12)
      • 12. Wang, Y., Delille, G., Bayem, H.: ‘High wind power penetration in isolated power systems—assessment of wind inertial and primary frequency response’, IEEE Trans. Power Syst., 2013, 28, (3), pp. 24122420.
    13. 13)
      • 13. Erlich, I., Wilch, M.: ‘Primary frequency control by wind turbines’. 2010 IEEE Power and Energy Society General Meeting, IEEE Power & Energy Society, Minnesota, USA, 2010, pp. 18.
    14. 14)
      • 14. Soni, N., Doolla, S., Chandorkar, M.C.: ‘Improvement of transient response in microgrids using virtual inertia’, IEEE Trans. Power Deliv., 2013, 28, (3), pp. 18301838.
    15. 15)
      • 15. Wang, Yi, Meng, J., Zhang, X., et al: ‘Control of PMSG-based wind turbines for system inertial response and power oscillation damping’, IEEE Trans. Sustain. Energy, 2015, 6, (2), pp. 565574.
    16. 16)
      • 16. Senjyu, T, Datta, M.: ‘A control method for small utility connected large PV system to reduce frequency deviation using a minimal-order observer’, IEEE Trans. Energy Convers., 2009, 24, (2), pp. 520528.
    17. 17)
      • 17. Liu, Z., Liu, F., Mei, S.: ‘Application of extended state observer in wind turbines speed recovery after inertia response control’, Proc. CSEE, 2016, 36, (5), pp. 12071217(in Chinese).
    18. 18)
      • 18. Liu, B., Yang, J., Liao, K., et al: ‘Improved frequency control strategy for DFIG-based wind turbines based on rotor kinetic energy control’, Autom. Electr. Power Syst., 2016, 40, (16), pp. 1722(in Chinese).
    19. 19)
      • 19. Fu, Y., Huang, L., Zhang, H., et al: ‘DFIG virtual inertia control in micro-grid based on setting trigger condition and ZN method for parameters optimization’, IET Gen. Transm. Distrib., 2017, 11, (15), pp. 37653775.
    20. 20)
      • 20. Zhao, J., Lü, X., Fu, Y., et al: ‘Frequency regulation of wind/photovoltaic/diesel microgrid based on DFIG cooperative strategy with variable coefficients between virtual inertia and over speed control’, Trans. China Eletrotech. Soc., 2015, 30, (9), pp. 5968(in Chinese).
    21. 21)
      • 21. Zhang, Z., Sun, Y., Li, G., et al: ‘Frequency regulation by doubly fed induction generator wind turbines based on coordinated overspeed control and pitch control’, Autom. Electr. Power Syst., 2011, 35, (17), pp. 2025(in Chinese).
    22. 22)
      • 22. Erlich, I., Wilch, M.: ‘Primary frequency control by wind turbines’. 2010 IEEE Power and Energy Society General Meeting, IEEE Power & Energy Society, Minnesota, USA, 2010, pp. 18.
    23. 23)
      • 23. Dey, R., Ghosh, S., Ray, G., et al: ‘H∞ load frequency control of interconnected power systems with communication delays’, Int. J. Electr. Power Energy Syst., 2012, 42, (1), pp. 672684.
    24. 24)
      • 24. Ersdal, A.M., Imsland, L., Uhlen, K. ‘Model predictive load-frequency control’, IEEE Trans. Power Syst., 2016, 31, (1), pp. 777785.
    25. 25)
      • 25. Mi, Y., Fu, Y., Li, D., et al: ‘The sliding mode load frequency control for hybrid power system based on disturbance observer’, Int. J. Electr. Power Energy Syst., 2016, 74, pp. 446452.
    26. 26)
      • 26. Senjyu, T.: ‘A frequency control method by wind farm & battery using load estimation in isolated power system’, Int. J. Emerg. Electr. Power Syst., 2010, 11, (2), preceding 1–20.
    27. 27)
      • 27. Luenburger, D.G.: ‘An introduction to observer’, IEEE Trans. Autom. Control, 1971, 16, (6), pp. 596602.
    28. 28)
      • 28. Mita, T.: ‘On the estimating errors and the structures of the identity observers and minimal order observers’, Int. J. Control, 1978, 27, (3), pp. 441454.
    29. 29)
      • 29. Gao, W.B., Wang, Y.F., Homaifa, A.: ‘Discrete time variable structure control systems’, IEEE Trans. Ind. Electron., 1995, 42, (2), pp. 117122.
    30. 30)
      • 30. Wang, Y., Zhou, R., Wen, C.: ‘Robust load-frequency controller design for power systems’, IEE Proc. C, Gener. Transm. Distrib., 1993, 140, (1), pp. 1116.

Related content

This is a required field
Please enter a valid email address