SEPARATE INTEGRATION OF SOLAR PVS INTO THE LOW-VOLTAGE DC LINK OF A SOLID-STATE TRANSFORMER BASED ON A MODULAR MULTILEVEL CONVERTER
DOI:
https://doi.org/10.59277/RRST-EE.2025.1.6Keywords:
Photovoltaic power systems, Solid-state transformer, DC-DC converter, Modular multilevel converterAbstract
This paper presents a photovoltaic system connected to a solid-state transformer (SST). The PVs are integrated into the low-voltage DC (LVDC) link. The SST consists of three stages containing combinations of converters: the modular multilevel converter MMC is employed in the medium voltage (LV) stage, the DC-DC converter is applied in the isolated stage, and a three-phase inverter is utilized in the low voltage (LV) stage. To ensure the smooth integration of PVs, it is essential to maintain a stable voltage at the LVDC level. To this end, the application control of the DC-DC converter must be used. The single-phase shift control (SPS) strategy was adopted. This control strategy maintains DC voltage levels at appropriate values and enables bidirectional power flow. In addition, to optimize the extraction of maximum power from the PVs, a maximum power point tracking (MPPT) technique is applied based on the M5P model decision tree. In parallel, to ensure optimal operation of the SST, a voltage-oriented control (VOC) and voltage capacitor balancing algorithm based on rotating gating signals is implemented for the MMC converter. In contrast, an unbalanced load control is applied to the inverter. The model developed in this study was implemented in MATLAB/Simulink, and the system's dynamic performance was validated.
References
(1) S. Khan, K. Rahman, M. Tariq, S. Hameed, B. Alamri, T.S. Babu, Solid-state transformers: fundamentals, topologies, applications, and future challenges, Sustainability, 14, 1, pp. 1319 (2022).
(2) D. Cervero, M. Fotopoulou, J. Muñoz-Cruzado, D. Rakopoulos, F. Stergiopoulos, N. Nikolopoulos, S. Voutetakis, J.F. Sanz, Solid state transformers: a critical review of projects with relevant prototypes and demonstrators, Electronics, 12, 4, pp. 931 (2023).
(3) X. She, A.Q. Huang, R. Burgos, Review of solid-state transformer technologies and their application in power distribution systems, IEEE Journal of Emerging and Selected Topics in Power Electronics, 1, 3, pp. 186–198 (2013).
(4) D.K. Mishra, M.J. Ghadi, L. Li, M.J. Hossain, J. Zhang, P.K. Ray, A. Mohanty, A review on solid-state transformer: a breakthrough technology for future smart distribution grids, International Journal of Electrical Power & Energy Systems, 133, pp. 107–255 (2021).
(5) R. Gao, X. She, I. Husain, A.Q. Huang, Solid-state-transformer interfaced permanent magnet wind turbine distributed generation system with power management functions, IEEE Transactions on Industry Applications, 53, 4, pp. 3849–3861 (2017).
(6) X. She, X. Yu, F. Wang, A.Q. Huang, Design and demonstration of a 3.6-kV-120-V/10-kVA solid-state transformer for smart grid application, Transactions on Power Electronics, 29, 8, pp. 3982–3997 (2014).
(7) M.A. Hannan, P.J. Ker, M.S.H. Lipu, Z.H. Choi, M.S.Abd. Rahman, K.M. Muttaqi, F. Blaabjerg, State of the art of solid-state transformers: advanced topologies, implementation issues, recent progress and improvements, IEEE Access, 8, pp. 19113–19132 (2020).
(8) M.M.E. Adabi, J.A. Martinez-Velasco, S. Alepuz, Modeling and simulation of a MMC-based solid-state transformer, Electrical Engineering, 100, 2, pp. 375–387 (2017).
(9) L.A.M. Barros, A.P. Martins, J.G. Pinto, A comprehensive review on modular multilevel converters, submodule topologies, and modulation techniques, Energies, 15, 3, 1078 (2022).
(10) M. Priya, P. Ponnambalam, K. Muralikumar, Modular-multilevel converter topologies and applications – a review, IET Power Electronics, 12, 1, 1–15 (2019).
(11) Q. Xi, Y. Tian, Y. Fan, Capacitor voltage balancing control of MMC sub-module based on neural network prediction, Electronics, 13, 4, 795 (2024).
(12) F. Gao, L. Xu, L. Zhang, A rotating gating signal method for capacitor voltage balancing in modular multilevel converters, IEEE Transactions on Power Electronics, 28, 1, 300–308 (2013).
(13) S. Kouser, G.R. Dheep, R.C. Bansal, Maximum power point tracking techniques for photovoltaic systems: a review, Renewable and Sustainable Energy Reviews, 159, 112–123 (2023).
(14) V.G. Dogaru, F.D. Dogaru, V. Năvrăpescu, L.M. Constantinescu, From the photovoltaic effect to a low voltage photovoltaic grid challenge – a review, Rev. Roum. Sci. Techn. – Électrotechn. et Énerg, 69, 3, pp. 263–268 (2024).
(15) M.L. Katche, A.B. Makokha, S.O. Zachary, M.S. Adaramola, A comprehensive review of maximum power point tracking (MPPT) techniques used in solar PV systems, Energies, 16, 5, pp. 2206 (2023).
(16) Y.K. Teklehaimanot, F.K. Akingbade, B.C. Ubochi, T.O. Ale, A review and comparative analysis of maximum power point tracking control algorithms for wind energy conversion systems, International Journal of Dynamics and Control, 12, pp. 3494–3516 (2024).
(17) S.A. Blaifi, S. Moulahoum, R. Benkercha, B. Taghezouit, A. Saim, M5P model tree-based fast fuzzy maximum power point tracker, Solar Energy, 163, 15, pp. 405–424 (2018).
(18) R. Teodorescu, L. Zarri, Modular multi-level converter: modeling, simulation, and control in steady state and dynamic conditions, Aalborg University (2012).
(19) M. Hagiwara, H. Akagi, Control and experiment of pulse width-modulated modular multilevel converters, IEEE Transactions on Power Electronics, 24, 7, pp. 1737–1746 (2009).
(20) R. Darus, J. Pou, G. Konstantinou, S. Ceballos, R. Picas, V.G. Agelidis, A modified voltage balancing algorithm for the modular multilevel converter: evaluation for staircase and phase-disposition PWM, IEEE Transactions on Power Electronics, 30, 1, pp. 298–310 (2015).
(21) W. Luo, Y. Ma, C. Zheng, Selection-based capacitor voltage balancing control for modular multilevel converters, Journal of Power Electronics, 21, pp. 1427–1438 (2021).
(22) G.P. Adam, O. Anaya-Lara, G.M. Burt, D. Telford, B.W. Williams, J.R. McDonald, Modular multilevel inverter: pulse width modulation and capacitor balancing technique, IET Power Electronics, 3, pp. 702–715 (2010).
(23) M. Alshammari, M. Duffy, Review of single-phase bidirectional inverter topologies for renewable energy systems with DC distribution, Energies, 15, 18, pp. 683 (2022).
(24) F. Jarraya, A. Khan, A. Gastli, L. Ben-Brahim, R. Hamila, Design considerations, modelling, and control of dual-active full bridge for electric vehicles charging applications, Journal of Engineering, 19, 1, pp. 5279 (2019).
(25) A. Bouhouta, S. Moulahoum, N. Kabache, A novel combined Fuzzy-M5P model tree control applied to grid-tied PVs with power quality consideration, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 44, 2, pp. 3125–3147 (2022).
(26) Y. Li, J. Zhang, Z. Hao, P. Tian, Improved PR control strategy for an LCL three-phase grid-connected inverter based on active damping, Applied Sciences, 11, 7, pp. 3170 (2021).
(27) J. Almaguer, V. Cárdenas, A. Aganza-Torres, M. González, J. Alcalá, A frequency-based LCL filter design and control considerations for three-phase converters for solid-state transformer applications, Electrical Engineering, 101, pp. 545–558 (2019).
Downloads
Published
Issue
Section
License
Copyright (c) 2025 REVUE ROUMAINE DES SCIENCES TECHNIQUES — SÉRIE ÉLECTROTECHNIQUE ET ÉNERGÉTIQUE
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
