An IoT Distributive SM Controller for Mitigation of Circulating Currents Among Sources in a Standalone DC Microgrid

Sharjeel Sarwar; Muhammad Rashad; Tayybah Kiren; Nazam Siddique; Bilal Ishfaq Ahmed; Adeel Ahmed; Muhammad Wasif; Jehanzaib Irshad

Authors

Sharjeel Sarwar Department of Electrical Engineering (The University of Lahore (UOL), Lahore, Pakistan).
Muhammad Rashad Electrical Engineering Department, The University of Lahore
Tayybah Kiren Department of Computer Science (University of Engineering and Technology (UET), Lahore, Pakistan).
Nazam Siddique Department of Electrical Engineering (University of Gujrat (UOG), Gujrat, Pakistan).
Bilal Ishfaq Ahmed Department of Informatics and Systems (University of Management and Technology (UMT), Lahore, Pakistan).
Adeel Ahmed Department of Electrical Engineering (The University of Lahore (UOL), Lahore, Pakistan).
Muhammad Wasif Department of Electrical Engineering (University of Gujrat (UOG), Gujrat, Pakistan
Jehanzaib Irshad Department of Electrical Engineering (University of Gujrat (UOG), Gujrat, Pakistan

Keywords:

Droop Control, Circulating Currents, Voltage Regulation, Sliding Mode Controller, Existence Condition, Stability Condition

Abstract

Sources of similar or different power ratings are connected in parallel within the DC microgrid. During operation, these sources generate circulating currents along with their normal currents, which disrupt proper current sharing among power electronic converters based on their capacity. Consequently, voltage regulation across the system weakens. Additionally, the resistance of the connecting lines contributes to this imbalance in current distribution. To address circulating currents, droop controllers are commonly used. This method allows converters to share power according to their capacity without requiring internal communication. However, a major drawback of conventional droop control is that as output voltage decreases, the converter's output current increases linearly, leading to significant voltage fluctuations. As a result, droop control inherently involves a trade-off between voltage regulation and current sharing, making it impossible to optimize both simultaneously. To overcome this issue, this paper proposes a sliding mode (SM) controller implemented through an IoT-based distributed architecture. A system model is developed to evaluate its performance, and conditions for stability and existence are analyzed. MATLAB simulations provide detailed experimental results, demonstrating the effectiveness of the proposed technique.

References

“Causes, Effects and Solutions to Global Energy Crisis - Conserve Energy Future.” https://www.conserve-energy-future.com/causes-and-solutions-to-the-global-energy-crisis.php.

V Manieniyan, M Thambidurai, and R Selvakumar, “Study On Energy Crisis And The Future Of Fossil Fuels,” 2009, doi: 10.13140/2.1.2234.3689.

R. E. H. Sims, “Renewable energy: a response to climate change,” Sol. Energy, vol. 76, no. 1, pp. 9–17, Jan. 2004, doi: 10.1016/S0038-092X(03)00101-4.

I. Dincer, “Renewable energy and sustainable development: a crucial review,” Renew. Sustain. Energy Rev., vol. 4, no. 2, pp. 157–175, Jun. 2000, doi: 10.1016/S1364-0321(99)00011-8.

X. Liu and B. Su, “Microgrids — an integration of renewable energy technologies,” in 2008 China International Conference on Electricity Distribution, Dec. 2008, pp. 1–7. doi: 10.1109/CICED.2008.5211651.

M. Shahbazitabar, H. Abdi, H. Nourianfar, A. Anvari-Moghaddam, B. Mohammadi-Ivatloo, and N. Hatziargyriou, “An Introduction to Microgrids, Concepts, Definition, and Classifications,” in Microgrids: Advances in Operation, Control, and Protection, A. Anvari-Moghaddam, H. Abdi, B. Mohammadi-Ivatloo, and N. Hatziargyriou, Eds., Cham: Springer International Publishing, 2021, pp. 3–16. doi: 10.1007/978-3-030-59750-4_1.

M. Rashad, U. Raoof, N. Siddique, B. A. Ahmed, and G. Abbas, “PWM Based Fixed Frequency Equivalent SM Controller for Stability of DC Microgrid System,” J. Eng. Res., Nov. 2022, doi: 10.36909/jer.ICEPE.19465

M. Rashad, M. Ashraf, A. I. Bhatti, and D. M. Minhas, “Mathematical modeling and stability analysis of DC microgrid using SM hysteresis controller,” Int. J. Electr. Power Energy Syst., vol. 95, pp. 507–522, Feb. 2018, doi: 10.1016/j.ijepes.2017.09.001.

M. Cucuzzella, J. M. A. Scherpen, and J. E. Machado, “Microgrids control: AC or DC, that is not the question,” EPJ Web Conf., vol. 310, p. 00015, 2024, doi: 10.1051/epjconf/202431000015.

J. Kumar, A. Agarwal, and V. Agarwal, “A review on overall control of DC microgrids,” J. Energy Storage, vol. 21, pp. 113–138, Feb. 2019, doi: 10.1016/j.est.2018.11.013.

M. Gomez-Redondo, M. Rivera, J. Muñoz, and P. Wheeler, “A Systematic Literature Review on AC Microgrids,” Designs, vol. 8, no. 4, Art. no. 4, Aug. 2024, doi: 10.3390/designs8040077.

M. Rashad and U. Raoof, “Equivalent SM Controller for Load-Sharing and Dynamic Performance in a DC Microgrid Application,” Math. Probl. Eng., vol. 2022, no. 1, p. 9700915, 2022, doi: 10.1155/2022/9700915.

V. J. Thottuvelil and G. C. Verghese, “Analysis and control design of paralleled DC/DC converters with current sharing,” in Proceedings of APEC 97 - Applied Power Electronics Conference, Feb. 1997, vol. 2, pp. 638–646 vol.2. doi: 10.1109/APEC.1997.575646.

Y. Huang and C. K. Tse, “Circuit Theoretic Classification of Parallel Connected DC-DC Converters,” IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 54, no. 5, pp. 1099–1108, May 2007, doi: 10.1109/TCSI.2007.890631.

S. Anand, B. G. Fernandes, and J. Guerrero, “Distributed Control to Ensure Proportional Load Sharing and Improve Voltage Regulation in Low-Voltage DC Microgrids,” IEEE Trans. Power Electron., vol. 28, no. 4, pp. 1900–1913, Apr. 2013, doi: 10.1109/TPEL.2012.2215055.

A. P. N. Tahim, D. J. Pagano, E. Lenz, and V. Stramosk, “Modeling and Stability Analysis of Islanded DC Microgrids Under Droop Control,” IEEE Trans. Power Electron., vol. 30, no. 8, pp. 4597–4607, Aug. 2015, doi: 10.1109/TPEL.2014.2360171.

S. Luo, Z. Ye, R.-L. Lin, and F. C. Lee, “A classification and evaluation of paralleling methods for power supply modules,” in 30th Annual IEEE Power Electronics Specialists Conference. Record. (Cat. No.99CH36321), Jul. 1999, vol. 2, pp. 901–908 vol.2. doi: 10.1109/PESC.1999.785618.

J. Rajagopalan, K. Xing, Y. Guo, F. C. Lee, and B. Manners, “Modeling and dynamic analysis of paralleled DC/DC converters with master-slave current sharing control,” in Proceedings of Applied Power Electronics Conference. APEC ’96, San Jose, CA, USA: IEEE, 1996, pp. 678–684. doi: 10.1109/APEC.1996.500513.

M. S. Sadabadi, N. Mijatovic, J.-F. Trégouët, and T. Dragičević, “Distributed Control of Parallel DC–DC Converters Under FDI Attacks on Actuators,” IEEE Transactions on Industrial Electronics, vol. 69, no. 10, pp. 10478–10488, Oct. 2022, doi: 10.1109/TIE.2021.3123613.

S. Trip, R. Han, M. Cucuzzella, X. Cheng, J. Scherpen, and J. Guerrero, “Distributed Averaging Control for Voltage Regulation and Current Sharing in DC Microgrids: Modelling and Experimental Validation,” IFAC-PapersOnLine, vol. 51, no. 23, pp. 242–247, Jan. 2018, doi: 10.1016/j.ifacol.2018.12.042.

M. Rashad, U. Raoof, M. Ashraf, and B. Ashfaq Ahmed, “Proportional Load Sharing and Stability of DC Microgrid with Distributed Architecture Using SM Controller,” Math. Probl. Eng., vol. 2018, no. 1, p. 2717129, 2018, doi: 10.1155/2018/2717129.

A. Nawaz, J. Wu, and C. Long, “Mitigation of circulating currents for proportional current sharing and voltage stability of isolated DC microgrid,” Electric Power Systems Research, vol. 180, p. 106123, Mar. 2020, doi: 10.1016/j.epsr.2019.106123.

S. I. Serna-Garcés, D. Gonzalez Montoya, and C. A. Ramos-Paja, “Sliding-Mode Control of a Charger/Discharger DC/DC Converter for DC-Bus Regulation in Renewable Power Systems,” Energies, vol. 9, no. 4, Art. no. 4, Apr. 2016, doi: 10.3390/en9040245.

V. Utkin, “Sliding Mode Control,” CONTROL Syst.