Similar articles

Abstract: The DC microgrid is connected to the AC utility by parallel bidirectional power converters (BPCs) to import/export large power, whose control directly affects the performance of the grid-connected DC microgrid. Much work has focused on the hierarchical control of the DC, AC, and hybrid microgrids, but little has considered the hierarchical control of multiple parallel BPCs that directly connect the DC microgrid to the AC utility. In this paper, we propose a hierarchical control for parallel BPCs of a grid-connected DC microgrid. To suppress the potential zero-sequence circulating current in the AC side among the parallel BPCs and realize feedback linearization of the voltage control, a d-q-0 control scheme instead of a conventional d-q control scheme is proposed in the inner current loop, and the square of the DC voltage is adopted in the inner voltage loop. DC side droop control is applied to realize DC current sharing among multiple BPCs at the primary control level, and this induces DC bus voltage deviation. The quantified relationship between the current sharing error and DC voltage deviation is derived, indicating that there is a trade-off between the DC voltage deviation and current sharing error. To eliminate the current sharing error and DC voltage deviation simultaneously, slope-adjusting and voltage-shifting approaches are adopted at the secondary control level. The proposed tertiary control realizes precise active and reactive power exchange through parallel BPCs for economical operation. The proposed hierarchical control is applied for parallel BPCs of a grid-connected DC microgrid and can operate coordinately with the control for controllable/uncontrollable distributional generation. The effectiveness of the proposed control method is verified by corresponding simulation tests based on Matlab/Simulink, and the performance of the hierarchical control is evaluated for practical applications.

联网型直流微电网并联双向变流器分层控制

[1]Anand, S., Fernandes, B.G., Guerrero, J., 2013. Distributed control to ensure proportional load sharing and improve voltage regulation in low-voltage DC microgrids. IEEE Trans. Power Electron., 28(4):1900-1913.

[2]Bao, J.Y., Bao, W.B., Zhang, Z.C., 2010. Generalized multilevel current source inverter topology with self-balancing current. J. Zhejiang Univ.-Sci. C (Comput. & Electron.), 11(7):555-561.

[3]Bao, X.W., Zhuo, F., Tian, Y., et al., 2013. Simplified feedback linearization control of three-phase photovoltaic inverter with an LCL filter. IEEE Trans. Power Electron., 28(6): 2739-2752.

[4]Bidram, A., Davoudi, A., Lewis, F.L., et al., 2013. Distributed cooperative secondary control of microgrids using feedback linearization. IEEE Trans. Power Syst., 28(3):3462-3470.

[5]Blasko, V., Kaura, V., 1997. A novel control to actively damp resonance in input LC filter of a three-phase voltage source converter. IEEE Trans. Ind. Appl., 33(2):542-550.

[6]Che, L., Shahidehpour, M., Alabdulwahab, A., et al., 2015. Hierarchical coordination of a community microgrid with AC and DC microgrids. IEEE Trans. Smart Grid, 6(6): 3042-3051.

[7]Chen, T.P., 2012. Zero-sequence circulating current reduction method for parallel HEPWM inverters between AC bus and DC bus. IEEE Trans. Ind. Electron., 59(1):290-300.

[8]Dragičević, T., Lu, X.N., Vasquez, J.C., et al., 2016. DC microgrids-part I: A review of control strategies and stabilization techniques. IEEE Trans. Power Electron., 31(7): 4876-4891.

[9]Eto, J., Lasseter, R., Schenkman, B., et al., 2009. Overview of the CERTS microgrid laboratory test bed. IEEE Trans. Power Del., 26(1):325-332.

[10]Gao, M.Z., Chen, M., Jin, C., et al., 2013. Analysis, design, and experimental evaluation of power calculation in digital droop-controlled parallel microgrid inverters. J. Zhejiang Univ.-Sci. C (Comput. & Electron.), 14(1): 50-64.

[11]Guerrero, J.M., Vasquez, J.C., Matas, J., et al., 2011. Hierarchical control of droop-controlled AC and DC microgrids—a general approach toward standardization. IEEE Trans. Ind. Electron., 58(1):158-172.

[12]Guo, T.T., Liu, X.L., Hao, S.Q., et al., 2015. Analysis and design of pulse frequency modulation dielectric barrier discharge for low power applications. Front. Inform. Technol. Electron. Eng., 16(3):249-258.

[13]Khorsandi, A., Ashourloo, M., Mokhtari, H., 2014. A decentralized control method for a low-voltage DC microgrid. IEEE Trans. Energy Conv., 29(4):793-801.

[14]Lasseter, R., Akhil, A., Marnay, C., et al., 2002. Consortium for Electric Reliability Technology Solutions. White Paper on Integration of Distributed Energy Resources. The CERTS MicroGrid Concept, p.1-29.

[15]Lee, T.S., 2003. Input-output linearization and zero-dynamics control of three-phase AC/DC voltage-source converters. IEEE Trans. Power Electron., 18(1):11-22.

[16]Loh, P.C., Li, D., Chai, Y.K., et al., 2013. Autonomous control of interlinking converter with energy storage in hybrid AC-DC microgrid. IEEE Trans. Ind. Appl., 49(3):1374-1382.

[17]Lu, X.N., Guerrero, J.M., Sun, K., et al., 2014a. Hierarchical control of parallel AC-DC converter interfaces for hybrid microgrids. IEEE Trans. Smart Grid, 5(2):683-692.

[18]Lu, X.N., Guerrero, J.M., Sun, K., et al., 2014b. An improved droop control method for DC microgrids based on low bandwidth communication with DC bus voltage restoration and enhanced current sharing accuracy. IEEE Trans. Power Electron., 29(4):1800-1812.

[19]Meng, L.X., Dragicevic, T., Vasquez, J.C., et al., 2015. Tertiary and secondary control levels for efficiency optimization and system damping in droop controlled DC-DC converters. IEEE Trans. Smart Grid, 6(6):2615-2626

[20]Nasirian, V., Davoudi, A., Lewis, F.L., et al., 2014. Distributed adaptive droop control for DC distribution systems. IEEE Trans. Energy Conv., 29(4):944-956.

[21]Nasirian, V., Moayedi, S., Davoudi, A., et al., 2015. Distributed cooperative control of DC microgrids. IEEE Trans. Power Electron., 30(4):2288-2303.

[22]Pan, C.T., Liao, Y.H., 2008. Modeling and control of circulating currents for parallel three-phase boost rectifiers with different load sharing. IEEE Trans. Ind. Electron., 55(7): 2776-2785.

[23]Shafiee, Q., Dragičević, T., Vasquez, J.C., et al., 2014. Hierarchical control for multiple DC-microgrids clusters. IEEE Trans. Energy Conv., 29(4):922-933.

[24]Torreglosa, J.P., García-Triviño, P., Fernández-Ramirez, L.M., et al., 2016. Control strategies for DC networks: a systematic literature review. Renew. Sust. Energy Rev., 58: 319-330.

[25]Unamuno, E., Barrena, J.A., 2015. Hybrid ac/dc micro-grids—Part II: review and classification of control strategies. Renew. Sustain. Energy Rev., 52:1123-1134.

[26]Wang, L.J., Yang, T., Zhang, D.M., et al., 2012. A high performance simulation methodology for multilevel grid-connected inverters. J. Zhejiang Univ.-Sci. C (Comput. & Electron.), 13(7):544-551.

[27]Wang, P.B., Lu, X.N., Yang, X., et al., 2016. An improved distributed secondary control method for DC microgrids with enhanced dynamic current sharing performance. IEEE Trans. Power Electron., 31(9):6658-6673.

[28]Xiao, H.G., Luo, A., Shuai, Z.K., et al., 2016. An improved control method for multiple bidirectional power converters in hybrid AC/DC microgrid. IEEE Trans. Smart Grid, 7(1):340-347.

[29]Xiao, J.F., Wang, P., Setyawan, L., 2016. Multilevel energy management system for hybridization of energy storages in DC microgrids. IEEE Trans. Smart Grid, 7(2):847-856.

[30]Xu, L., Chen, D., 2011. Control and operation of a DC microgrid with variable generation and energy storage. IEEE Trans. Power Del., 26(4):2513-2522.

[31]Ye, Z.H., Boroyevich, D., Choi, J.Y., et al., 2002. Control of circulating current in two parallel three-phase boost rectifiers. IEEE Trans. Power Electron., 17(5):609-615.

[32]Zhang, D., Wang, F.F., Burgos, R., et al., 2011. Common-mode circulating current control of paralleled interleaved three-phase two-level voltage-source converters with discontinuous space-vector modulation. IEEE Trans. Power Electron., 26(12):3925-3935.