Advances in Energy Research

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Modified droop control scheme for load sharing amongst inverters in a micro grid

  • Patel, Urvi N. (Department of Electrical Engineering, C.K. Pithawalla College of Engineering & Technology) ;
  • Gondalia, Dipakkumar (Department of Electrical Engineering, Sarvajanik College of Engineering & Technology) ;
  • Patel, Hiren H. (Department of Electrical Engineering, Sarvajanik College of Engineering & Technology)
  • Received : 2015.03.11
  • Accepted : 2015.06.09
  • Published : 2015.06.25
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Abstract

Microgrid, which can be considered as an integration of various dispersed resources (DRs), is characterized by number of DRs interfaced through the power electronics converters. The microgrid comprising these DRs is often operated in an islanded mode. To minimize the cost, reduce complexity and increase reliability, it is preferred to avoid any communication channel between them. Consequently, the droop control method is traditionally adopted to distribute active and reactive power among the DRs operating in parallel. However, the accuracy of distribution of active and reactive power among the DRs controlled by the conventional droop control approach is highly dependent on the value of line impedance, R/X i.e., resistance to reactance ratio of the line, voltage setting of inverters etc. The limitations of the conventional droop control approach are demonstrated and a modified droop control approach to reduce the effect of impedance mis-match and improve the time response is proposed. The error in reactive power sharing is minimized by inserting virtual impedance in line with the inverters to remove the mis-match in impedance. The improved time response is achieved by modifying the real-power frequency droop using arctan function. Simulations results are presented to validate the effectiveness of the control approach.

Keywords

References

  1. Broeck, H.V. and Boeke, U. (1998), "A simple method for parallel operation of inverters", Telecommunications Energy Conference, INTELEC, Twentieth International, 143-150.
  2. Chandorkar, M.C., Divan, D.M. and Adapa, R. (1993), "Control of parallel connected inverters in standalone ac supply systems", IEEE Trans. Ind. Appl., 29(1), 136 - 143. https://doi.org/10.1109/28.195899
  3. Duan, S., Meng, Y., Xiong, J., Kang, Y. and Chen, J. (1999), "Parallel operation control technique of voltage source inverters in UPS", IEEE International Conference on Power Electronics and Drive Systems, PEDS'99, Hong Kong.
  4. Guerrero, J.M., Matas, J., Garcia De Vicuna, L., Castilla, M. and Miret, J. (2007), "Decentralized control for parallel operation of distributed generation inverters using resistive output impedance", IEEE Trans. Ind Electron., 54(2), 994-1004. https://doi.org/10.1109/TIE.2007.892621
  5. Guerrero, J.M., Matas, J., Vicuna, D., Garcia, L., Castilla, M. and Miret, J. (2006), "Wireless-control strategy for parallel operation of distributed generation inverters", IEEE Trans. Ind. Electron., 53(5), 1461-1470. https://doi.org/10.1109/TIE.2006.882015
  6. Guerrero, J.M., Vicuna, D., Garcia, L., Matas, J., Castilla, M. and Miret, J. (2005), "Output impedance design for parallel-connected UPS inverters with wireless load sharing control", IEEE Trans. Ind. Electron., 52(4), 1126-1135. https://doi.org/10.1109/TIE.2005.851634
  7. Guerrero, J.M., Vicuna, D., Garcia, L., Matas, J., Castilla, M. and Miret, J. (2004), "A wireless controller to enhance dynamic performance of parallel inverters in distributed generation systems", IEEE Trans. Power Electron., 9, 1205-1213.
  8. He, J. and Li, Y.W. (2010), "Analysis, design, and implementation of virtual impedance for power electronics interfaced distributed generation", IEEE Trans. Ind. Appl., 47(6), 2525-2538. https://doi.org/10.1109/TIA.2011.2168592
  9. Li, Y.W. and Kao, C.N. (2009), "An accurate power control strategy for power electronics interfaced distributed generation units operating in a low voltage multibus microgrid", IEEE Trans. Power Electron., 24(12), 2977-2988. https://doi.org/10.1109/TPEL.2009.2022828
  10. Matas, J., Castilla, M., de Vicuna, L.G., Miret, J. and Vasquez, J.C. (2010), "Virtual impedance loop for droop-controlled single-phase parallel inverters using a second- order general-integrator scheme", IEEE Trans. Power Electron., 25(12), 2993-3002. https://doi.org/10.1109/TPEL.2010.2082003
  11. Rowe, C., Summers, T.J. and Betz, R. (2010), "Arctan power frequency droop for power electronics dominated microgrids", Proc. Australas. Univ. Power Eng. Conf., 1-6.
  12. Rowe, C., Summers, T.J., Betz, R. and Cornforth, D. (2011), "Small signal stability analysis of arctan power frequency droop", Proc. Power Electron. Drive Syst. Conf., 787-792.
  13. Rowe, C., Summers, T.J. and Betz, R. and Cornforth, D. and Moore, T.G. (2013), "Arc tan powerfrequency droop for improved microgrid stability", IEEE Trans. Power Electron., 28(8), 3747-3759. https://doi.org/10.1109/TPEL.2012.2230190
  14. Sabar, F.A., Mohammadi, H., Ketabi, A. and Masoud, S. (2000), "Control of parallel inverters in distributed AC power systems with consideration of line impedance effect", IEEE Trans. Ind. Appl., 36(1) 131-138. https://doi.org/10.1109/28.821807
  15. Tuladhar, A., Jin, H., Unger, T. and Mauch, K. (1997), "Parallel operation of single phase inverter modules with no control interconnections", Proc. 12th Annu. APEC, 1, 94-100.
  16. Wu, T.F., Chen, Y.K. and Huang, Y.H. (2000), "3C strategy for inverters in parallel operation achieving an equal current distribution", IEEE Trans. Ind. Electron., 47(2), 273-281. https://doi.org/10.1109/41.836342
  17. Zhong, Q.C. (2013), "Robust droop controller for accurate proportional load sharing among inverters operated in parallel", IEEE Trans. Ind. Electron., 60(4), 3747-3459.

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