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http://dx.doi.org/10.6113/JPE.2018.18.4.1245

Droop Control Scheme of a Three-phase Inverter for Grid Voltage Unbalance Compensation  

Liu, Hongpeng (Department of Electrical Engineering, Harbin Institute of Technology)
Zhou, Jiajie (Department of Electrical Engineering, Harbin Institute of Technology)
Wang, Wei (Department of Electrical Engineering, Harbin Institute of Technology)
Xu, Dianguo (Department of Electrical Engineering, Harbin Institute of Technology)
Publication Information
Journal of Power Electronics / v.18, no.4, 2018 , pp. 1245-1254 More about this Journal
Abstract
The stability of a grid-connected system (GCS) has become a critical issue with the increasing utilization of renewable energy sources. Under grid faults, however, a grid-connected inverter cannot work efficiently by using only the traditional droop control. In addition, the unbalance factor of voltage/current at the common coupling point (PCC) may increase significantly. To ensure the stable operation of a GCS under grid faults, the capability to compensate for grid imbalance should be integrated. To solve the aforementioned problem, an improved voltage-type grid-connected control strategy is proposed in this study. A negative sequence conductance compensation loop based on a positive sequence power droop control is added to maintain PCC voltage balance and reduce grid current imbalance, thereby meeting PCC power quality requirements. Moreover, a stable analysis is presented based on the small signal model. Simulation and experimental results verify the aforementioned expectations, and consequently, the effectiveness of the proposed control scheme.
Keywords
Active power; Droop control; Grid-connected inverter; Negative sequence; Positive sequence; Reactive power; Unbalance compensation;
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1 R. Rodriguez, A. V. Timbus, R. Teodorescu, M. Liserre, and F. Blaabjerg, "Flexible active power control of distributed power generation systems during grid faults," IEEE Trans. Ind. Electron., Vol. 54, No. 5, pp. 2583-2592, Oct. 2007.   DOI
2 A. Camacho, M. Castilla, J. Miret, R. Guzman, and A. Borrell, "Reactive power control for distributed generation power plants to comply with voltage limits during grid faults," IEEE Trans. Power Electron., Vol. 29, No. 11, pp. 6224-6234, Nov. 2014.   DOI
3 A. A. Montanari and A. M. Gole, "Enhanced instantaneous power theory for control of grid connected voltage sourced converters under unbalanced conditions," IEEE Trans. Power Electron., Vol. 32, No. 8, pp. 6652-6660, Aug. 2017.   DOI
4 J. M. Guerrero, J. C. Vasquez, J. Matas, L. G. de 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.   DOI
5 H. Bevrani and S. Shokoohi, "An intelligent droop control for simultaneous voltage and frequency regulation in islanded microgrids," IEEE Smart Grid, Vol. 4, No. 3, pp. 1505-1513, Sep. 2013.   DOI
6 M. Hamzeh, H. Karimi, and H. Mokhtari, "A new control strategy for a multi-bus MV microgrid under unbalanced conditions," IEEE Trans. Power Syst., Vol. 27, No. 4, pp. 2225-2232, Nov. 2012.   DOI
7 X. Zhao, J. M. Guerrero, M. Savaghebi, J. C. Vasquez, X. H. Wu, and K. Sun, "Low-voltage ride-through operation of power converters in grid-interactive microgrids by using negative-sequence droop control," IEEE Trans. Power Electron., Vol. 32, No. 4, pp. 3128-3142, Apr. 2017.   DOI
8 N. R. Merritt, C. Chakraborty, and P. Bajpai, "New voltage control strategies for VSC-based DG units in an unbalanced microgrid," IEEE Trans. Sustain. Energy, Vol. 8, No. 3, pp. 1127-1139, Jul. 2017.   DOI
9 M. Mirhosseini, J. Pou, and V. G. Agelidis, "Individual phase current control with the capability to avoid overvoltage in grid-connected photovoltaic power plants under unbalanced voltage sags," IEEE Trans. Power Electron., Vol. 30, No. 10, pp. 5346-5351, Oct. 2015.   DOI
10 X. Q. Guo, W. Z. Liu, X. Zhang, X. F. Sun, Z. G. Lu, and J. M. Guerrero, "Flexible control strategy for grid-connected inverter under unbalanced grid faults without PLL," IEEE Trans. Power Electron., Vol. 30, No. 4, pp. 1773-1778, Apr. 2015.   DOI
11 A. Camacho, M. Castilla, J. Miret, P. Marti, and M. Velasco, "Maximizing positive sequence voltage support in inductiveresistive grids for distributed generation inverters during voltage sags," in Proc. IECON, pp. 2343-2348, 2016.
12 A. Camacho, M. Castilla, J. Miret, J. C. Vasquez, and E. Alarcon-Gallo, "Flexible voltage support control for three-phase distributed generation inverters under grid fault," IEEE Trans. Ind. Electron., Vol. 60, No. 4, pp. 1429-1441, Apr. 2013.   DOI
13 X. Q. Guo, X. Zhang, B. C. Wang, W. Y. Wu and J. M. Guerrero, "Asymmetrical grid fault ride-through strategy of three-phase grid-connected inverter considering network impedance impact in low-voltage grid." IEEE Trans. Power Electron., Vol. 29, No. 3, pp. 1064-1068, Mar. 2014.   DOI
14 M. Ciobotaru, R. Teodorescu, and F. Blaabjerg, "A new single-phase PLL structure based on second order generalized integrator," in Proc. IEEE PESC, pp. 1-6, 2006.
15 Q. C. Zhong and G. C. Konstantopoulos, "Current-limiting droop control of grid-connected invertes," IEEE Trans. Ind. Electron., Vol. 64, No. 7, pp. 5963-5973, Jul. 2017.   DOI
16 R. R. Kolluri, I. Mareels, T. Alpcan, J. de Hoog, and D. A. Thomas, "Power sharing in angle droop controlled microgrids," IEEE Trans. Power Syst., Vol. 32, No. 6, pp. 4743-4751, Nov. 2017.   DOI
17 Y. Suh and T. A. Lipo, "Control scheme in hybrid synchronous stationary frame for PWM AC/DC converter under generalized unbalanced operating conditions," IEEE Trans. Ind. Appl., Vol. 42, No. 3, pp. 825-835, May/Jun. 2006.   DOI
18 M. Reyes, P. Rodriguez, S. Vazquez, A. Luna, R. Teodorescu, and J. M. Carrasco, "Enhanced decoupled double synchronous reference frame current controller for unbalanced grid-voltage conditions," IEEE Trans. Power Electron., Vol. 27, No. 9, pp. 3934-3943, Sep. 2012.   DOI
19 X. Wang, X. Ruan, S. Liu, and C. K. Tse, "Full feedforward of grid voltage for grid-connected inverter with LCL filter to suppress current distortion due to grid voltage harmonics," IEEE Trans. Power Electron., Vol. 25, No. 12, pp. 3119-3127, Dec. 2010.   DOI