Revista Eletrônica de Potência (Brazilian Journal of Power Electronics)

Palavras Chaves: Controle droop, Controle Hierárquico, Controle mestre-escravo, estabilidade

Resumo
Neste artigo apresenta-se um estudo comparativo entre técnicas aplicadas ao controle de conversores cc-cc com saídas conectadas em paralelo. Este tipo de conexão é comum em aplicações envolvendo microrredes, em que um mesmo barramento CC é compartilhado entre diversos estágios de processamento de energia. As técnicas de controle abordadas neste artigo diferenciam-se quanto à forma de implementação, que pode ser local ou coordenado. Além de apresentarem diferentes comportamentos quanto à complexidade, robustez, modularidade e rastreamento de referência, tais técnicas influenciam a estabilidade do sistema, uma vez que alteram a impedância equivalente de saída dos conversores. A fim de avaliar tais características, o artigo compara experimentalmente as técnicas de controle do tipo droop, hierárquico e mestre-escravo, e apresenta uma análise da estabilidade em nível de eletrônica de potência, considerando um sistema composto por três conversores Boost com saídas compartilhadas.

Title: Control and stability analysis of DC-DC converters under power sharing mode

Keywords: Droop Control, Hierarchical Control, Master-Slave Control, stability

Abstract
In this paper, a comparative study among techniques applied to the control of dc-dc converters with parallel-connected outputs is presented. This type of connection is usual in microgrid applications, in which a single DC bus is shared among several power stages. The control techniques discussed in this paper can be classified as local or coordinated. Besides presenting different behaviors regarding complexity, robustness, modularity and reference tracking, such techniques influence the entire system stability, since they change the equivalent impedance of the converters. In order to evaluate such characteristics, the paper experimentally compares the droop, hierarchical and master-slave control techniques, and presents an analysis of the stability in the power electronics level, regarding a system composed of three Boost converters with shared outputs.

[1] R. F. Coelho, Concepção, Análise e Implementação de uma Microrrede Interligada à Rede Elétrica Para Alimentação Ininterrupta de Cargas CC a Partir de Fontes Renováveis, Tese, Universidade Federal de Santa Catarina – UFSC, Florianópolis, 2013.
[2] K. Sun, L. Zhang, Y. Xing, J. M. Guerrero, A Distributed Control Strategy Based on DC Bus Signaling for Modular Photovoltaic Generation Systems With Battery Energy Storage, IEEE Trans. Power Electron., vol. 26, no 10, p. 3032–3045, out. 2011, https://doi.org/10.1109/TPEL.2011.2127488.
[3] T. Dragicevic, X. Lu, J. C. Vasquez, J. M. Guerrero, DC Microgrids Part I: A Review of Control Strategies and Stabilization Techniques, IEEE Trans. Power Electron., vol. 31, no 7, p. 4876–4891, jul. 2016, https://doi.org/10.1109/TPEL.2015.2478859.
[4] L. Meng, T. Dragicevic, J. M. Guerrero, J. C. Vasquez, Dynamic consensus algorithm based distributed global efficiency optimization of a droop controlled DC microgrid, in IEEE International Energy Conference (ENERGYCON), p. 1276–1283, 2014, https://doi.org/10.1109/ENERGYCON.2014.6850587.
[5] J. Schonbergerschonberger, R. Duke, S. D. Round, DC-Bus Signaling: A Distributed Control Strategy for a Hybrid Renewable Nanogrid, IEEE Transactions on Industrial Electronics, vol. 53, no 5, p. 1453–1460, out. 2006, https://doi.org/10.1109/TIE.2006.882012.
[6] T. Dragicevic, J. M. Guerrero, J. C. Vasquez, D. Škrlec, Supervisory Control of an Adaptive-Droop Regulated DC Microgrid With Battery Management Capability, IEEE Transactions on Power Electronics, vol. 29, no 2, p. 695–706, fev. 2014, https://doi.org/10.1109/TPEL.2013.2257857.
[7] C. Jin, P. Wang, J. Xiao, Y. Tang, F. H. Choo, Implementation of Hierarchical Control in DC Microgrids, IEEE Transactions on Industrial Electronics, vol. 61, no 8, p. 4032–4042, ago. 2014, https://doi.org/10.1109/TIE.2013.2286563.
[8] L. Che, M. Shahidehpour, DC Microgrids: Economic Operation and Enhancement of Resilience by Hierarchical Control, IEEE Transactions on Smart Grid, vol. 5, no 5, p. 2517–2526, set. 2014, https://doi.org/10.1109/TSG.2014.2344024.
[9] R. Olfati-Saber, J. A. Fax, R. M. Murray, Consensus and Cooperation in Networked Multi-Agent Systems, Proceedings of the IEEE, vol. 95, no 1, p. 215–233, jan. 2007, https://doi.org/10.1109/JPROC.2006.887293.
[10] L. Meng, T. Dragicevic, J. C. Vasquez, J. M. Guerrero, J. R. Pérez, Modeling and sensitivity analysis of consensus algorithm based distributed hierarchical control for DC microgrids, in IEEE Applied Power Electronics Conference and Exposition (APEC), p. 342–349, 2015, https://doi.org/10.1109/APEC.2015.7104373.
[11] J. W. Kim, H. S. Choi, B. H. Cho, A novel droop method for the converter parallel operation, in IEEE Applied Power Electronics Conference and Exposition (APEC), p. 959–964, 2001, https://doi.org/10.1109/APEC.2001.912483.
[12] B. T. Irving, M. M. Jovanovic, Analysis, design, and performance evaluation of droop current-sharing method, in IEEE Applied Power Electronics Conference and Exposition (APEC), p. 235–241, 2000, https://doi.org/10.1109/APEC.2000.826110.
[13] A. Riccobono, J. Siegers, E. Santi, Stabilizing positive feed-forward control design for a DC power distribution system using a passivity-based stability criterion and system bus impedance identification, in IEEE Applied Power Electronics Conference and Exposition (APEC), p. 1139–1146, 2014, https://doi.org/10.1109/APEC.2014.6803450.
[14] A. Emadi, A. Ehsani, Dynamics and control of multi-converter DC power electronic systems, in IEEE Power Electronics Specialists Conference (IEEE PESC), p. 248–253, 2001, https://doi.org/10.1109/PESC.2001.954028.
[15] A. Riccobono, E. Santi, Comprehensive Review of Stability Criteria for DC Power Distribution Systems, IEEE Trans. Ind. Appl., vol. 50, no 5, p. 3525–3535, set. 2014, https://doi.org/10.1109/TIA.2014.2309800.
[16] H. Li, J. Shang, X. You, T. Zheng, B. Zhang, J. Lü, A Novel Stability Analysis Method based on Floquent Theory for Cascaded DC-DC Converter Systems, in IEEE Energy Conversion Congress and Exposition (ECCE), pp. 2679-2683, 2015, https://doi.org/10.1109/ECCE.2015.7310035.
[17] C. Shin-Young, L. Il-Oun, M. Gun-Woo, Graphical small-signal modeling based on the inductor waveform, in IECON 2012 – 38th Annual Conference on IEEE Industrial Electronics Society, 2012, p. 1301–1305, https://doi.org/10.1109/IECON.2012.6388551.