Journal of Power Electronics

The Korean Institute of Power Electronics (전력전자학회)
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Current and power quality multi-objective control of virtual synchronous generators under unbalanced grid conditions

  • Wu, Jian (School of Electrical Engineering and Automation, Harbin Institute of Technology) ;
  • Liu, Tong (School of Electrical Engineering and Automation, Harbin Institute of Technology) ;
  • Qiu, Tianyi (School of Electrical Engineering and Automation, Harbin Institute of Technology) ;
  • Xu, Dianguo (School of Electrical Engineering and Automation, Harbin Institute of Technology)
  • Received : 2019.07.30
  • Accepted : 2019.11.04
  • Published : 2020.03.20
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Abstract

In recent years, with the large-scale application of distributed power sources in the power grid, the power grid is moving toward low inertia and low damping. The virtual synchronous generator (VSG) has become a hot topic for scholars since it can simulate the moment of inertia, damping and frequency modulation of synchronous generators. Due to its unbalanced load distribution and the random variation of power loads, grid voltage is asymmetrical. Under grid voltage asymmetry, a VSG experiences output current imbalance and power oscillation. The grid current imbalance further reduces the transformer's three-phase voltage, which makes it unequal, cyclic, and very easy to cause electricity accidents. Aiming at this problem, this paper proposes three modes of current balance, reactive power balance and active power balance without changing the characteristics of VSGs. The output current balance and power are constant when the grid voltage is asymmetrical. The effectiveness and feasibility of the control strategy are verified by simulation and experimental results, which provides an effective scheme for balanced and stable operation of the grid.

Keywords

References

  1. Lu, L.Y., Chu, C.C.: Consensus-based secondary frequency and voltage droop control of virtual synchronous generators for isolated ac micro-grids. IEEE J. Emerg. Sel. Top. Circuits Syst. 5(3), 443-455 (2017) https://doi.org/10.1109/JETCAS.2015.2462093
  2. Malik, S.M., Ai, X., Sun, Y., et al.: Voltage and frequency control strategies of hybrid AC/DC microgrid: a review. IET Gen. Transm. Distrib. 11(2), 303-313 (2017) https://doi.org/10.1049/iet-gtd.2016.0791
  3. Camilo, F.M., Rui, C., Almeida, M.E., et al.: Assessment of overvoltage mitigation techniques in low-voltage distribution networks with high penetration of photovoltaic microgeneration. IET Renew. Power Gen. 12(6), 649-656 (2018) https://doi.org/10.1049/iet-rpg.2017.0482
  4. Hang, L., Zhang, M.: Constant power control-based strategy for Vienna-type rectifiers to expand operating area under severe unbalanced grid. IET Power Electron. 7(1), 41-49 (2014) https://doi.org/10.1049/iet-pel.2012.0450
  5. Zhao, Y.: Speed-sensorless control for grid-connected doubly-fed induction generators based on virtual synchronous generator. J. Eng. 14, 2660-2665 (2017) https://doi.org/10.1049/joe.2017.0832
  6. Alipoor, J., Miura, Y., Ise, T.: Stability assessment and optimization methods for microgrid with multiple VSG units. IEEE Trans. Smart Grid 9(2), 1462-1471 (2018) https://doi.org/10.1109/tsg.2016.2592508
  7. Andalib, B., Liang, X., Zhang, H.: Fuzzy secondary controller based virtual synchronous generator control scheme for interfacing inverters of renewable distributed in microgrids. IEEE Trans. Ind. Appl. 54(2), 1047-1061 (2017) https://doi.org/10.1109/tia.2017.2773432
  8. Shi, K., Song, W., Xu, P., et al.: Low-voltage ride-through control strategy for a virtual synchronous generator based on smooth switching. IEEE Access 6, 2703-2711 (2018) https://doi.org/10.1109/access.2017.2784846
  9. Kabiri, R., Holmes, D.G., Mcgrath, B.P.: Control of active and reactive power ripple to mitigate unbalanced grid voltages. IEEE Trans. Ind. Appl. 52(2), 1660-1668 (2017) https://doi.org/10.1109/TIA.2015.2508425
  10. Wang, X.H., Sun, D.: Multi-objective self-synchronised virtual synchronous generator in unbalanced power grid. Electron. Lett. 54(12), 779-781 (2018) https://doi.org/10.1049/el.2018.1217
  11. Sun, D., Wang, X.H.: Low-complexity model predictive direct power control for DFIG under both balanced and unbalanced grid conditions. IEEE Trans. Ind. Electron. 63(8), 5186-5196 (2016) https://doi.org/10.1109/TIE.2016.2570201
  12. Jiao, Y.Z., Nian, H., He, G.Q.: Control strategy based on virtual synchronous generator of DFIG-based wind turbine under unbalanced grid voltage. In: 20th International Conference on Electrical Machines and Systems, pp. 1-6 (2017)
  13. Chen, M., Xiao, X.N., Yuan, C., et al.: Flexible power control of virtual synchronous generators under unbalanced grid voltage conditions. In: IEEE Energy Conversion Congress and Exposition (ECCE), pp. 2881-2888 (2017)

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