Adjusting output impedance using a PI controller to improve the stability of a single-phase inverter under weak grid

Jiao Jiao, R. Mark Nelms

Abstract


Explored in this paper is the grid impedance effect on the stability of a single-phase grid connected inverter with an LC filter based on an analysis of the inverter output impedance. For a single-phase grid connected inverter, a PI controller is often used to regulate the current injected into the grid. However, the control performance can be influenced when the inverter is connected to a weak grid. Also, the utility grid has background harmonic noise, which can make the injected current distorted. Therefore, analysis of the output impedance of a single-phase grid connected inverter is important for the robustness and stability of the system. By modeling the output impedance of inverter, it can be determined that the proportional gain and integral gain of the controller have an effect on the output impedance. Analytical results show that by adjusting the PI controller parameters, the ability for harmonic reduction and stability of the system can be improved. Simulation and experiments using a 1 kW single-phase grid connected inverter verify the effectiveness of the theoretical analysis.

Keywords


grid impedance; inverter output impedance; LC filter; PI controller; single-phase inverter

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References


Liserre, M., Teodorescu, R., Blaabjerg, F., "Stability of photovoltaic and wind turbine grid-connected inverters for a large set of grid impedance values," Power Electronics, IEEE Transactions on , vol.21, no.1, pp.263,272, Jan. 2006.

Jian Sun, "Impedance-Based Stability Criterion for Grid-Connected Inverters," in Power Electronics, IEEE Transactions on , vol.26, no.11, pp.3075-3078, Nov. 2011.

M. Céspedes and J. Sun, "Impedance shaping of three-phase grid-parallel voltage-source converters," 2012 Twenty-Seventh Annual IEEE Applied Power Electronics Conference and Exposition (APEC), Orlando, FL, 2012, pp. 754-760.

D. Yang, X. Ruan and H. Wu, "Impedance Shaping of the Grid-Connected Inverter with LCL Filter to Improve Its Adaptability to the Weak Grid Condition," in IEEE Transactions on Power Electronics, vol. 29, no. 11, pp. 5795-5805, Nov. 2014.

Xiao-Qiang Li, Xiao-Jie Wu, Yi-Wen Geng, and Qi Zhang; “Stability Analysis of Grid-Connected Inverters with an LCL Filter Considering Grid Impedance”, Journal of Power Electronics, Vol. 13, No. 5, September 2013.

V. Blasko and V. Kaura, "A novel control to actively damp resonance in input LC filter of a three phase voltage source converter," Applied Power Electronics Conference and Exposition, 1996. APEC '96. Conference Proceedings 1996., Eleventh Annual, San Jose, CA, 1996, pp. 545-551 vol.2.

F. Wang, J. L. Duarte, M. A. M. Hendrix and P. F. Ribeiro, "Modeling and Analysis of Grid Harmonic Distortion Impact of Aggregated DG Inverters," in IEEE Transactions on Power Electronics, vol. 26, no. 3, pp. 786-797, March 2011.

Y. Tao, Q. Liu, Y. Deng, X. Liu and X. He, "Analysis and Mitigation of Inverter Output Impedance Impacts for Distributed Energy Resource Interface," in IEEE Transactions on Power Electronics, vol. 30, no. 7, pp. 3563-3576, July 2015.




DOI: http://dx.doi.org/10.22149/teee.v1i4.61

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