An Optimal Error-Driven Sequential Approach for the Dual-Loop Fractional-Order Control of a PFC Converter in Solid-State Transformers

Articles in Press

Document Type : Research paper

Authors

Energy Management Research Center, University of Mohaghegh Ardabili, Ardabil, Iran.

Abstract

The increasing complexity of current power systems has made improving their dependability and operational efficiency a primary focus of research. The dynamic performance and adaptability of conventional low-frequency transformers equipped with tap changers are inherently limited. As an alternative, Solid-State Transformers (SSTs) are favored due to their smaller size, higher reliability, and improved controllability. However, their nonlinear behavior, numerous switching devices, and passive elements like capacitors demand advanced, high-speed, and robust control strategies to unlock their full potential. Therefore, achieving stable output voltage and regulated input current through an effective Dual-Loop control (DLC) mechanism is essential. In this study, an optimal design of the DLC strategy is proposed for a power factor correction converter, which serves as the front-end stage of an SST. This combined control scheme merges a fractional-order proportional-integral (FOPI) controller with a conventional PI regulator. The controllers are designed to maintain voltage and current ripples within acceptable thresholds, even under load disturbances and changes in system parameters. To achieve this, DLC tuning is carried out using the Coati optimization algorithm, aiming to reduce the ISTSE cost function as much as possible and improve overall system behavior. To verify the effectiveness of the proposed strategy, a thorough comparison is carried out with other control techniques, including standard single-loop control (SLC), PI-PI-based DLC, and the proposed PI-FOPI-based DLC, under different operating conditions and using various optimization algorithms. The numerical results clearly demonstrate that the proposed design significantly enhances the converter’s dynamic behavior compared to the typical SLC configuration, achieving up to 77% better performance in terms of rise time and settling time.

Keywords

Main Subjects

References

  1. M. E. Zaman, M. A. Kayum, M. K. H. Chowdhury, and T. Barai, “Us renewable energy capacity in 2024: Sustainable transition and global competitiveness,” 2025.
  2. H. Molla-Ahmadian, M. Shafie, J. Khorasani, F. Tahani, and R. Kheiri, “Integrated modeling of bidirectional solid-state transformers with an arbitrary number of h-bridge converters,” Sci. Iran., 2024.
  3. M. Cavdar and S. Ozcira Ozkilic, “A novel linear-based closed-loop control and analysis of solid-state transformer,” Electron., vol. 13, no. 16, p. 3253, 2024.
  4. A. B. Kunya, A. Nasir, and M. B. Garba, “Assessment of the state-of-the-art of solid-state transformer technology: Design, control and application,” Struct., 2024.
  5. S. Balci, S. Ozdemir, N. Altin, and I. Sefa, “Solid state transformer: Topologies, design and its applications in a smart grid,” in Smart Grid 3.0: Comput. Commun. Technol., pp. 275–300, Springer, 2023.
  6. D.-M. Predescu and S.-G. Rosu, “Solid-state transformers: A review-part ii: Modularity and applications,” Technol., vol. 13, no. 2, p. 50, 2025.
  7. M. A. Hannan, P. J. Ker, M. S. H. Lipu, Z. H. Choi, M. S. A. Rahman, K. M. Muttaqi, and F. Blaabjerg, “State of the art of solid-state transformers: Advanced topologies, implementation issues, recent progress and improvements,” IEEE Access, vol. 8, pp. 19113–19132, 2020.
  8. H. Shayeghi, A. Rahnama, and H. Mojarad, “Designing a multi-objective optimized parallel process controller for frequency stabilization in an islanded microgrid,” J. Oper. Autom. Power Eng., 2025.
  9. S. A. K. Mojlish, D. Sutanto, and K. M. Muttaqi, “Impacts of ultra-fast charging of electric vehicles on power grids: State-of-the-art technologies, case studies, and a proposed improvement using a solid-state transformer,” J. Energy Storage, vol. 107, p. 114913, 2025.
  10. H. Mojarad, H. Shayeghi, and R. Mohajery, “Coati-based optimal design of a 2-dof pid controller for a ky buck-boost converter,” in 2025 12th Iran. Conf. Renewable Energies Distrib. Gener., pp. 1–6, IEEE, 2025.
  11. Y. Yerkin, A. H. O. Al Mansor, A. A. Ibrahim, A. R. T. Zaboun, J. K. Abbas, S. H. Hlail, D. A. Lafta, and K. Al-Majdi, “Boost dc-dc converter design for improved performance and stability of fuel cell using model predictive control and firefly optimization algorithm,” J. Oper. Autom. Power Eng., vol. 11, no. Special Issue, 2024.
  12. S. A. M. Saleh, C. Richard, X. F. S. Onge, K. M. McDonald, E. Ozkop, L. Chang, and B. Alsayid, “Solid-state transformers for distribution systems–part i: Technology and construction,” IEEE Trans. Ind. Appl., vol. 55, no. 5, pp. 4524–4535, 2019.
  13. H. M. van der Broocke Campos, J. W. M. Soares, A. A. Badin, and D. F. Cortez, “Single-phase hybrid switchedcapacitor pfc boost rectifier with low voltage gain,” IEEE Trans. Power Electron., vol. 38, no. 1, pp. 968–976, 2022.
  14. A. Jain, K. K. Gupta, S. K. Jain, and P. Bhatnagar, “A bidirectional five-level buck pfc rectifier with wide output range for ev charging application,” IEEE Trans. Power Electron., vol. 37, no. 11, pp. 13439–13455, 2022.
  15. T. Liu, Y. Song, and W. Chen, “Design and implementation of linear and nonlinear feedforward controllers for highperformance power factor corrected circuits,” IET Power Electron., vol. 18, no. 1, p. e70010, 2025.
  16. A. Kumar, U. Sharma, and B. Singh, “Sensorless singleswitch pfc converter fed brushless direct current motor ceiling fan,” IEEE Trans. Consum. Electron., vol. 69, no. 3, pp. 331–342, 2023.
  17. Y.-H. Liao, B.-R. Xie, and J.-S. Liu, “Modeling and control of current sensorless pfc three-phase vienna rectifier with balanced and unbalanced dc-link voltage,” IEEE Trans. Power Electron., 2024.
  18. M. Lee, C.-S. Yeh, O. Yu, J.-W. Kim, J.-M. Choe, and J.-S. Lai, “Modeling and control of three-level boost rectifier based medium-voltage solid-state transformer for dc fast charger application,” IEEE Trans. Transp. Electrific., vol. 5, no. 4, pp. 890–902, 2019.
  19. S.-H. Kim, Y.-H. Jang, and R.-Y. Kim, “Modeling and hierarchical structure based model predictive control of cascaded flying capacitor bridge multilevel converter for active front-end rectifier in solid-state transformer,” IEEE Trans. Ind. Electron., vol. 66, no. 8, pp. 6560–6569, 2018.
  20. M. L. Pay, J. Christensen, F. He, L. Roden, H. Ahmed, and M. Foo, “Pll-based enhanced control of boost pfc converter for smart farming lighting application,” Renew. Energy Focus, vol. 47, p. 100502, 2023.
  21. H. Vahedi and K. Al-Haddad, “A novel multilevel multioutput bidirectional active buck pfc rectifier,” IEEE Trans. Ind. Electron., vol. 63, no. 9, pp. 5442–5450, 2016.
  22. S. Avila-Becerril, J. R. Rodríguez-Rodríguez, A. VelazquezIbañez, and M. R. Arrieta-Paternina, “Grid-following voltage source converter with a pll-less pi passivity-based controller for unbalanced grid conditions,” IEEE Trans. Power Electron., 2025.
  23. S.-L. An, X.-D. Sun, Q. Zhang, Y.-R. Zhong, and B.-Y. Ren, “Study on the novel generalized discontinuous svpwm strategies for three-phase voltage source inverters,” IEEE Trans. Ind. Inform., vol. 9, no. 2, pp. 781–789, 2012.
  24. L. Gong, G. Fu, X. Wang, M. Tang, W. Liao, and Y. Miao, “Research on signal extraction and control strategy of singlephase pwm rectifier in dq coordinate frame,” in Int. Conf. Wireless Power Transfer, pp. 1087–1095, Springer, 2022.
  25. Y. Tian, X. Xu, W. Liu, and Y. Wang, “Pwm rectifier imitating linearization control for diode rectifier through a boost-pfc circuit with improved controllability and suppressed harmonics,” IEEE Trans. Power Electron., 2024.
  26. G. Flores, R. Verdín, and Y. Zhang, “Dynamic load compensation and stabilization in bilinear ac/dc rectifiers under unknown load conditions and disturbances,” Control Eng. Pract., vol. 164, p. 106401, 2025.
  27. R. Mohajery, H. Shayeghi, and J. L. Villanueva, “Psotvac based optimized fopid controller for cascaded dc-dc boost converter,” Int. J. Tech. Phys. Probl. Eng., vol. 13, pp. 139–146, 2021.
  28. H. Shayeghi, A. Rahnama, N. Bizon, and A. Szumny, “Interconnected microgrids load-frequency control using stage-by-stage optimized tida+ 1 error signal regulator,” Eng. Rep., vol. 7, no. 1, p. e13095, 2025.
  29. E. Çelik, “Exponential pid controller for effective load frequency regulation of electric power systems,” ISA Trans., vol. 153, pp. 364–383, 2024.
  30. A. G. S. Sánchez, F.-J. Perez-Pinal, and A. Espinosa-Calderón, “Optimization and its implementation impact of two-modes controller fractional approximation for buck converters,” Micromachines, vol. 13, no. 10, p. 1600, 2022.
  31. M. Jabari, D. Izci, S. Ekinci, M. Bajaj, and I. Zaitsev, “Performance analysis of dc-dc buck converter with innovative multi-stage pidn (1+ pd) controller using geo algorithm,” Sci. Rep., vol. 14, no. 1, p. 25612, 2024.
  32. Y. Liu, A. As’arry, H. Ahmed, A. A. Hairuddin, M. K. Hassan, M. Z. Zakaria, and S. Yang, “Online optimal tuning
    of fuzzy pid controller using grey wolf optimizer for quarter car semi-active suspension system,” Adv. Mech. Eng., vol. 16, no. 2, p. 16878132231219620, 2024.
  33. H. Gursoy Demir, “Grey wolf optimization-and particle swarm optimization-based pd/i controllers and dc/dc buck converters designed for pem fuel cell-powered quadrotor,” Drones, vol. 9, no. 5, p. 330, 2025.
  34. S. Dutta, S. Gangavarapu, A. K. Rathore, R. K. Singh, S. K. Mishra, and V. Khadkikar, “Novel single-phase cuk-derived bridgeless pfc converter for on-board ev charger with reduced number of components,” IEEE Trans. Ind. Appl., vol. 58, no. 3, pp. 3999–4010, 2022.
  35. S. Dutta, S. Gangavarapu, V. R. Vakacharla, A. K. Rathore, V. Khadkikar, and H. Zeineldin, “Small signal analysis and control of single-phase bridgeless cuk-based pfc converter for on-board ev charger,” in 2021 IEEE Transp. Electrific. Conf. Expo, pp. 851–855, IEEE, 2021.
  36. H. Vahedi, E. Pashajavid, and K. Al-Haddad, “Fixed-band fixed-frequency hysteresis current control used in apfs,” in IECON 2012-38th Annu. Conf. IEEE Ind. Electron. Soc., pp. 5944–5948, IEEE, 2012.
  37. F. Babaei and A. Safari, “Sca based fractional-order pid controller considering delayed ev aggregators,” J. Oper. Autom. Power Eng., vol. 8, no. 1, pp. 75–85, 2020.
  38. M. A. Abdelbaky, H. M. Emara, M. I. El-Hawwary, A. Bahgat, and X. Liu, “Implementation of fractionalorder pid controller using industrial dcs with experimental validation,” in 2020 IEEE 4th Conf. Energy Internet Energy Syst. Integr., pp. 4407–4413, IEEE, 2020.
  39. M. Dehghani, Z. Montazeri, E. Trojovská, and P. Trojovský, “Coati optimization algorithm: A new bio-inspired metaheuristic algorithm for solving optimization problems,” Knowl.-Based Syst., vol. 259, p. 110011, 2023.
  40. H. Khoramikia, S. M. Dehghan, and S. Hasanzadeh, “Droop control method based on fuzzy adaptive virtual resistance for dc microgrids,” Int. J. Power Electron., vol. 14, no. 2, pp. 197–215, 2021.
  41. Z. Guan, C. Ren, J. Niu, P. Wang, and Y. Shang, “Great wall construction algorithm: A novel meta-heuristic algorithm for engineer problems,” Expert Syst. Appl., vol. 233, p. 120905, 2023.
Journal of Operation and Automation in Power Engineering

Articles in Press, Corrected Proof
Available Online from 16 October 2025

Files

History

  • Receive Date: 09 July 2025
  • Revise Date: 28 July 2025
  • Accept Date: 29 July 2025
  • First Publish Date: 16 October 2025

Share

How to cite

Statistics