Secondary Voltage Control for Reactive Power Sharing in an Islanded Microgrid

- Journal title : Journal of Power Electronics
- Volume 16, Issue 1, 2016, pp.329-339
- Publisher : The Korean Institute of Power Electronics
- DOI : 10.6113/JPE.2016.16.1.329

Title & Authors

Secondary Voltage Control for Reactive Power Sharing in an Islanded Microgrid

Guo, Qian; Wu, Hongyan; Lin, Liaoyuan; Bai, Zhihong; Ma, Hao;

Guo, Qian; Wu, Hongyan; Lin, Liaoyuan; Bai, Zhihong; Ma, Hao;

Abstract

Owing to mismatched feeder impedances in an islanded microgrid, the conventional droop control method typically results in errors in reactive power sharing among distributed generation (DG) units. In this study, an improved droop control strategy based on secondary voltage control is proposed to enhance the reactive power sharing accuracy in an islanded microgrid. In a DG local controller, an integral term is introduced into the voltage droop function, in which the voltage compensation signal from the secondary voltage control is utilized as the common reactive power reference for each DG unit. Therefore, accurate reactive power sharing can be realized without any power information exchange among DG units or between DG units and the central controller. Meanwhile, the voltage deviation in the microgrid common bus is removed. Communication in the proposed strategy is simple to implement because the information of the voltage compensation signal is broadcasted from the central controller to each DG unit. The reactive power sharing accuracy is also not sensitive to time-delay mismatch in the communication channels. Simulation and experimental results are provided to validate the effectiveness of the proposed method.

Keywords

Droop control;Microgrid;Reactive power sharing;Secondary voltage control;

Language

English

Cited by

References

1.

D. E. Olivares, A. Mehrizi-Sani, A. H. Etemadi, C. A. Cañizares, and R. Palma-Behnke, “Trends in microgrid control,” IEEE Trans. Smart Grid, Vol. 5, No. 4, pp. 1905-1919, Jul. 2014.

2.

X. Wang, J. M. Guerrero, F. Blaabjerg and Z. Chen, “A review of power electronics based microgrids,” Journal of Power Electronics, Vol. 12, No. 1, pp. 181-192, Jan. 2012.

3.

J. Rocabert, A. Luna, F. Blaabjerg, and P. Rodríguez,“Control of power converters in AC microgrids,” IEEE Trans. Power Electron., Vol. 27, No. 11, pp. 4734-4749, Nov. 2012.

4.

J. M. Guerrero, J. C. Vasquez, J. Matas, L. Vicuna, 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, Jan. 2011.

5.

X. Zhang, J. Liu, Z. You, and T. Liu, “Study on the influence of distribution lines to parallel inverter systems adopting the droop control method,” Journal of Power Electronics, Vol. 13, No. 4, pp. 701-711, Jul. 2013.

6.

W. Yao, M. Chen, J. Matas, J. M. Guerrero, and Z. Qian, “Design and analysis of the droop control method for parallel inverters considering the impact of the complex impedance on the power sharing,” IEEE Trans. Ind. Electron., Vol. 58, No. 2, pp. 576-588, Feb. 2011.

7.

H. Mahmood, D. Michaelson, and J. Jiang, “Accurate reactive power sharing in an islanded microgrid using adaptive virtual impedances,” IEEE Trans. Power Electron., Vol. 30, No. 3, pp. 1605-1617, Mar. 2015.

8.

J. M. Guerrero, J. Matas, L. Vicuna, M. Castilla, and J. Miret, “Wireless-control strategy for parallel operation of distributed-generation inverters,” IEEE Trans. Ind. Electron., Vol. 53, No. 5, pp. 1461-1470, Oct. 2006.

9.

Z. Guo, D. Sha, and X. Liao, “Wireless paralleled control strategy of three-phase inverter modules for islanding distributed generation systems,” Journal of Power Electronics, Vol. 13, No. 3, pp. 479-486, May 2013.

10.

J. M. Guerrero, J. Matas, L. Vicuna, M. Castilla, and J. Miret, “Decentralized control for parallel operation of distributed generation inverters using resistive output impedance,” IEEE Trans. Ind. Electron., Vol. 54, No. 2, pp. 994-1004, Apr. 2007.

11.

Q. Zhong and Y. Zeng, “Control of inverters via a virtual capacitor to achieve capacitive output impedance,” IEEE Trans. Power Electron., Vol. 29, No. 10, pp. 5568-5578, Oct. 2014.

12.

J. He, Y. W. Li, J. M. Guerrero, F. Blaabjerg, and J. C. Vasquez, “An islanding microgrid power sharing approach using enhanced virtual impedance control scheme,” IEEE Trans. Power Electron., Vol. 28, No. 11, pp. 5272-5282, Nov. 2013.

13.

C.-T. Lee, C.-C. Chu, and P.-T. Cheng, “A new droop control method for the autonomous operation of distributed energy resource interface converters,” IEEE Trans. Power Electron., Vol. 28, No. 4, pp. 1980-1993, Apr. 2013.

14.

Q. Zhong, “Robust droop controller for accurate proportional load sharing among inverters operated in parallel,” IEEE Trans. Ind. Electron., Vol. 60, No. 4, pp. 1281-1290, Apr. 2013.

15.

C. K. Sao and P. W. Lehn, “Autonomous load sharing of voltage source converters,” IEEE Trans. Power Del., Vol. 20, No. 2, pp. 1009-1016, Apr. 2005.

16.

Y. Zhang and H. Ma, “Theoretical and experimental investigation of networked control for parallel operation of inverters,” IEEE Trans. Ind. Electron., Vol. 59, No. 4, pp. 1961-1970, Apr. 2012.

17.

J. He and Y. W. Li, “An enhanced microgrid load demand sharing strategy,” IEEE Trans. Power Electron., Vol. 27, No. 9, pp. 3984-3995, Sep. 2012.

18.

J. He, Y. W. Li, and F. Blaabjerg, “An enhanced islanding microgrid reactive power, imbalance power, and harmonic power sharing scheme,” IEEE Trans. Power Electron., Vol. 30, No. 6, pp. 3389-3401, Jun. 2015.

19.

H. Han, Y. Liu, Y. Sun, M. Su, and J. M. Guerrero, “An improved droop control strategy for reactive power sharing in islanded microgrid,” IEEE Trans. Power Electron., Vol. 30, No. 6, pp. 3133-3141, Jun. 2015.

20.

A. Bidram and A. Davoudi, “Hierarchical structure of microgrids control system,” IEEE Trans. Smart Grid, Vol. 3, No. 4, pp. 1963-1976, Dec. 2012.

21.

M. Savaghebi, A. Jalilian, J. C. Vasquez, and J. M. Guerrero, “Secondary control for voltage quality enhancement in microgrids,” IEEE Trans. Smart Grid, Vol. 3, No. 4, pp. 1893-1902, Dec. 2012.

22.

A. Micallef, M. Apap, C. Spiteri-Staines, J. M. Guerrero, and J. C. Vasquez, “Reactive power sharing and voltage harmonic distortion compensation of droop controlled single phase islanded microgrids,” IEEE Trans. Smart Grid, Vol. 5, No. 3, pp. 1149-1158, May 2014.

23.

A. Micallef, M. Apap, C. S. Staines, and J. M. Guerrero Zapata, "Secondary control for reactive power sharing and voltage amplitude restoration in droop-controlled islanded microgrids," in 3rd IEEE International Symposium on Power Electronics for Distributed Generation Systems(PEDG), pp. 492-498, Jun. 2012.

24.

Q. Shafiee, J. M. Guerrero, and J. C. Vasquez, “Distributed secondary control for islanded microgrids – A novel approach,” IEEE Trans. Power Electron., Vol. 29, No. 2, pp. 1018-1031, Feb. 2014.

25.

Q. Shafiee, C. Stefanovic, T. Dragicevic, P. Popovski, J. C. Vasquez, and J. M. Guerrero, “Robust networked control scheme for distributed secondary control of islanded microgrids,” IEEE Trans. Ind. Electron., Vol. 61, No. 10, pp. 5363-5374, Oct. 2014.