{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T08:46:26Z","timestamp":1775033186846,"version":"3.50.1"},"reference-count":46,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,1,18]],"date-time":"2021-01-18T00:00:00Z","timestamp":1610928000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Energies"],"abstract":"<jats:p>Rail power conditioner (RPC) has the ability to improve the power quality in AC railway power grids. This power conditioner can increase the loading capacity of traction substations, balance the active power between the feeder load sections, and compensate for reactive power and current harmonics. At present, there is increasing use of multilevel converter topologies, which provide scalability and robust performance under different conditions. In this framework, modular multilevel converter (MMC) is emerging as a prominent solution for medium-voltage applications. Serving that purpose, this paper focuses on the implementation, testing, and validation of a reduced-scale laboratory prototype of a proposed RPC based on an MMC. The developed laboratory prototype, designed to be compact, reliable, and adaptable to multipurpose applications, is presented, highlighting the main control and power circuit boards of the MMC. In addition, MMC parameter design of the filter inductor and submodule capacitor is also explained. Experimental analysis and validation of a reduced-scale prototype RPC based on MMC topology, are provided to verify the power quality improvement in electrified railway power grids. Thus, two experimental case studies are presented: (1) when both of the load sections are unequally loaded; (2) when only one load section is loaded. Experimental results confirm the RPC based on MMC is effective in reducing the harmonic contents, solving the problem of three-phase current imbalance and compensating reactive power.<\/jats:p>","DOI":"10.3390\/en14020484","type":"journal-article","created":{"date-parts":[[2021,1,19]],"date-time":"2021-01-19T04:55:31Z","timestamp":1611032131000},"page":"484","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Experimental Validation of a Reduced-Scale Rail Power Conditioner Based on Modular Multilevel Converter for AC Railway Power Grids"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1050-2779","authenticated-orcid":false,"given":"Mohamed","family":"Tanta","sequence":"first","affiliation":[{"name":"School of Engineering, Campus of Azur\u00e9m, University of Minho, 4800-058 Guimar\u00e3es, Portugal"}]},{"given":"Jose","family":"Cunha","sequence":"additional","affiliation":[{"name":"School of Engineering, Campus of Azur\u00e9m, University of Minho, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6623-3980","authenticated-orcid":false,"given":"Luis A. M.","family":"Barros","sequence":"additional","affiliation":[{"name":"School of Engineering, Campus of Azur\u00e9m, University of Minho, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6640-8955","authenticated-orcid":false,"given":"Vitor","family":"Monteiro","sequence":"additional","affiliation":[{"name":"School of Engineering, Campus of Azur\u00e9m, University of Minho, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4289-4770","authenticated-orcid":false,"given":"Jos\u00e9 Gabriel Oliveira","family":"Pinto","sequence":"additional","affiliation":[{"name":"School of Engineering, Campus of Azur\u00e9m, University of Minho, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4162-7833","authenticated-orcid":false,"given":"Antonio P.","family":"Martins","sequence":"additional","affiliation":[{"name":"Faculty of Engineering, University of Porto, Rua Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9195-1239","authenticated-orcid":false,"given":"Joao L.","family":"Afonso","sequence":"additional","affiliation":[{"name":"School of Engineering, Campus of Azur\u00e9m, University of Minho, 4800-058 Guimar\u00e3es, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Farnesi, S., Marchesoni, M., and Vaccaro, L. (2016, January 22\u201324). Advances in Locomotive Power Electronic Systems Directly Fed through AC Lines. Proceedings of the 2016 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), Anacapri, Italy.","DOI":"10.1109\/SPEEDAM.2016.7525932"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"00013","DOI":"10.1051\/matecconf\/202032000013","article-title":"Locomotive Noise Reduction","volume":"Volume 320","author":"Nesterov","year":"2020","journal-title":"MATEC Web of Conferences"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Perin, I., Nussey, P.F., Cella, U.M., Tran, T.V., and Walker, G.R. (2015, January 9\u201312). Application of Power Electronics in Improving Power Quality and Supply Efficiency of AC Traction Networks. Proceedings of the 2015 IEEE 11th International Conference on Power Electronics and Drive Systems, Sydney, Australia.","DOI":"10.1109\/PEDS.2015.7203421"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1080\/23248378.2016.1169228","article-title":"Power Quality in High-Speed Railway Systems","volume":"4","author":"He","year":"2016","journal-title":"Int. J. Rail Transp."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"6653","DOI":"10.1109\/TVT.2017.2661820","article-title":"Power Quality Conditioning in Railway Electrification: A Comparative Study","volume":"66","author":"Langerudy","year":"2017","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Morais, V.A., Afonso, J.L., Carvalho, A.S., and Martins, A.P. (2020). New Reactive Power Compensation Strategies for Railway Infrastructure Capacity Increasing. Energies, 13.","DOI":"10.3390\/en13174379"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3081","DOI":"10.1109\/TIE.2014.2386794","article-title":"Power Quality Issues in Railway Electrification: A Comprehensive Perspective","volume":"62","author":"Gazafrudi","year":"2015","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2844","DOI":"10.1109\/TPEL.2011.2128888","article-title":"Railway Static Power Conditioners for High-Speed Train Traction Power Supply Systems Using Three-Phase V\/V Transformers","volume":"26","author":"Luo","year":"2011","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_9","first-page":"52","article-title":"Railway Static Power Conditioner for Shin-Kurobe Substation of Hokuriku Shinkansen","volume":"61","author":"Oso","year":"2015","journal-title":"Fuji Electr. Rev."},{"key":"ref_10","unstructured":"Tanta, M., Pinto, G., Monteiro, V., Martins, A.P., Carvalho, A.S., and Afonso, J.L. (2018, January 16\u201319). A Comprehensive Comparison of Rail Power Conditioners Based on Two-Level Converters and a V\/V Power Transformer in Railway Traction Power Systems. Proceedings of the 7th Transport Research Arena (TRA 2018), Vienna, Austria."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Langerudy, A.T., and Mariscotti, A. (2016, January 18\u201320). Tuning of a Railway Power Quality Conditioner. Proceedings of the 2016 18th Mediterranean Electrotechnical Conference (MELECON), Lemesos, Cyprus.","DOI":"10.1109\/MELCON.2016.7495328"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1016\/j.ijepes.2017.05.008","article-title":"Electrical Railway Power Supply Systems: Current Situation and Future Trends","volume":"92","author":"Abrahamsson","year":"2017","journal-title":"Int. J. Electr. Power Energy Syst."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Afonso, J.L., Cardoso, L.A.L., Pedrosa, D., Sousa, T.J.C., Machado, L., Tanta, M., and Monteiro, V. (2020). A Review on Power Electronics Technologies for Electric Mobility. Energies, 13.","DOI":"10.3390\/en13236343"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Tanta, M., Barros, L.A.M., Pinto, G., Martins, A.P., and Afonso, J.L. (2020, January 3). Modular Multilevel Converter in Electrified Railway Systems: Applications of Rail Static Frequency Converters and Rail Power Conditioners. Proceedings of the 2020 International Young Engineers Forum (YEF ECE), Costa da Caparica, Portugal.","DOI":"10.1109\/YEF-ECE49388.2020.9171814"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2553","DOI":"10.1109\/TIE.2010.2049719","article-title":"Recent Advances and Industrial Applications of Multilevel Converters","volume":"57","author":"Kouro","year":"2010","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1109\/TPEL.2014.2309937","article-title":"Operation, Control, and Applications of the Modular Multilevel Converter: A Review","volume":"30","author":"Debnath","year":"2015","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_17","unstructured":"Knaak, H.J. (September, January 30). Modular Multilevel Converters and HVDC\/FACTS: A Success Story. Proceedings of the 2011 14th European Conference on Power Electronics and Applications, Birmingham, UK."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1109\/TTE.2018.2792330","article-title":"Modular Multilevel Converters for Transportation Electrification: Challenges and Opportunities","volume":"4","author":"Ronanki","year":"2018","journal-title":"IEEE Trans. Transp. Electrif."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Barros, L.A.M., Tanta, M., Martins, A.P., Afonso, J.L., and Pinto, J.G. (2020, January 8\u201310). Opportunities and Challenges of Power Electronics Systems in Future Railway Electrification. Proceedings of the 2020 IEEE 14th International Conference on Compatibility, Power Electronics and Power Engineering (CPE-POWERENG), Setubal, Portugal.","DOI":"10.1109\/CPE-POWERENG48600.2020.9161695"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1534","DOI":"10.1109\/TPEL.2010.2085088","article-title":"A Transformerless Medium-Voltage STATCOM Topology Based on Extended Modular Multilevel Converters","volume":"26","author":"Mohammadi","year":"2011","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1237","DOI":"10.1109\/JESTPE.2017.2685464","article-title":"Power Electronic Transformer-Based Railway Traction Systems: Challenges and Opportunities","volume":"5","author":"Feng","year":"2017","journal-title":"IEEE J. Emerg. Sel. Top. Power Electron."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"6031","DOI":"10.1109\/TPEL.2016.2616721","article-title":"Analysis and Comparison of Modular Railway Power Conditioner for High-Speed Railway Traction System","volume":"32","author":"Xu","year":"2016","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_23","unstructured":"Tanta, M., Pinto, G., Monteiro, V., Martins, A.P., Carvalho, A.S., and Afonso, J.L. (2019, January 16). Cost Estimation of Rail Power Conditioner Topologies Based on Indirect Modular Multilevel Converter in V\/V and Scott Power Transformers. Proceedings of the 4th International Conference on Energy and Environment: Bringing together Engineering and Economics, Guimar\u00e3es, Portugal."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Qin, F., Hao, T., and Gao, F. (2019, January 19\u201321). A Railway Power Conditioner Using Direct AC-AC Modular Multilevel Converter. Proceedings of the 2019 2nd International Conference on Smart Grid and Renewable Energy (SGRE), Doha, Qatar.","DOI":"10.1109\/SGRE46976.2019.9020681"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"7275","DOI":"10.1109\/TIE.2016.2563379","article-title":"Multilevel Power Conditioner and Its Model Predictive Control for Railway Traction System","volume":"63","author":"Ma","year":"2016","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Tanta, M., Pinto, J.G., Monteiro, V., Martins, A.P., Carvalho, A.S., and Afonso, J.L. (2020). Topologies and Operation Modes of Rail Power Conditioners in AC Traction Grids: Review and Comprehensive Comparison. Energies, 13.","DOI":"10.3390\/en13092151"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1348","DOI":"10.1109\/TPWRD.2017.2755505","article-title":"Fundamental-Frequency Reactive Circulating Current Injection for Capacitor Voltage Balancing in Hybrid-MMC HVDC Systems During Riding Through PTG Faults","volume":"33","author":"Lu","year":"2018","journal-title":"IEEE Trans. Power Deliv."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1109\/MELE.2016.2584998","article-title":"Future of Electric Railways: Advanced Electrification Systems with Static Converters for AC Railways","volume":"4","author":"Krastev","year":"2016","journal-title":"IEEE Electrif. Mag."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"165018","DOI":"10.1109\/ACCESS.2019.2949099","article-title":"A Novel Advanced Traction Power Supply System Based on Modular Multilevel Converter","volume":"7","author":"He","year":"2019","journal-title":"IEEE Access"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1109\/TPEL.2014.2310127","article-title":"Circuit Topologies, Modeling, Control Schemes, and Applications of Modular Multilevel Converters","volume":"30","author":"Perez","year":"2015","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Tanta, M., Pinto, J.G., Monteiro, V., Martins, A.P., Carvalho, A.S., and Afonso, J.L. (2020). Deadbeat Predictive Current Control for Circulating Currents Reduction in a Modular Multilevel Converter Based Rail Power Conditioner. Appl. Sci., 10.","DOI":"10.3390\/app10051849"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Tanta, M., Monteiro, V., Exposto, B., Pinto, J.G., Martins, A.P., Carvalho, A.S., Mel\u00e9ndez, A.A.N., and Afonso, J.L. (November, January 29). Simplified Rail Power Conditioner Based on a Half-Bridge Indirect AC\/DC\/AC Modular Multilevel Converter and a V\/V Power Transformer. Proceedings of the IECON 2017\u201443rd Annual Conference of the IEEE Industrial Electronics Society, Beijing, China.","DOI":"10.1109\/IECON.2017.8217120"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1737","DOI":"10.1109\/TPEL.2009.2014236","article-title":"Control and Experiment of Pulsewidth-Modulated Modular Multilevel Converters","volume":"24","author":"Hagiwara","year":"2009","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1464","DOI":"10.1109\/TIE.2013.2261035","article-title":"Linear and Pseudolinear Enhanced Phased-Locked Loop (EPLL) Structures","volume":"61","year":"2014","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"728","DOI":"10.1109\/TIE.2012.2206358","article-title":"A Simplified Power Conditioner Based on Half-Bridge Converter for High-Speed Railway System","volume":"60","author":"Ma","year":"2013","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Dai, N., and Wong, M. (2011, January 21\u201323). Design Considerations of Coupling Inductance for Active Power Filters. Proceedings of the 2011 6th IEEE Conference on Industrial Electronics and Applications, Beijing, China.","DOI":"10.1109\/ICIEA.2011.5975801"},{"key":"ref_37","unstructured":"Tu, Q., Xu, Z., Huang, H., and Zhang, J. (2010, January 24\u201328). Parameter Design Principle of the Arm Inductor in Modular Multilevel Converter Based HVDC. Proceedings of the 2010 International Conference on Power System Technology, Hangzhou, China."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2526","DOI":"10.1109\/TIE.2012.2194974","article-title":"Dynamic Analysis of Modular Multilevel Converters","volume":"60","author":"Harnefors","year":"2013","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Liu, L., and Dai, N. (2016, January 18\u201322). Hybrid Railway Power Conditioner Based on Half-Bridge Modular Multilevel Converter. Proceedings of the 2016 IEEE Energy Conversion Congress and Exposition (ECCE), Milwaukee, WI, USA.","DOI":"10.1109\/ECCE.2016.7855177"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Sharifabadi, K., Harnefors, L., Nee, H.-P., Norrga, S., and Teodorescu, R. (2016). Design, Control and Application of Modular Multilevel Converters for HVDC Transmission Systems, Wiley-IEEE Press.","DOI":"10.1002\/9781118851555"},{"key":"ref_41","unstructured":"Afonso, J.L., Monteiro, V., and Pinto, J.G. (2019, January 4\u20136). STATCOM Evaluation in Electrified Railway Using V\/V and Scott Power Transformers. Proceedings of the Sustainable Energy for Smart Cities, SESC 2019, Braga, Portugal."},{"key":"ref_42","unstructured":"(2018, October 09). Silicon Labs Si824x\u2014Class D Audio Driver with Precision Dead-Time Generator. Available online: https:\/\/www.silabs.com\/documents\/public\/data-sheets\/Si824x.pdf."},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Tanta, M., Cunha, J., Monteiro, V., Martins, A.P., Carvalho, A.S., and Afonso, J.L. (2019, January 14\u201317). A Novel Hardware Protection Scheme for a Modular Multilevel Converter Half-Bridge Submodule. Proceedings of the IECON 2019\u201445th Annual Conference of the IEEE Industrial Electronics Society, Lisbon, Portugal.","DOI":"10.1109\/IECON.2019.8927361"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"3569","DOI":"10.1109\/TIA.2014.2308357","article-title":"Reliability of Capacitors for DC-Link Applications in Power Electronic Converters\u2014An Overview","volume":"50","author":"Wang","year":"2014","journal-title":"IEEE Trans. Ind. Appl."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1080\/09398368.2017.1417785","article-title":"Design, Implementation and Testing of a Modular Multilevel Converter","volume":"27","author":"Gruson","year":"2017","journal-title":"EPE J."},{"key":"ref_46","unstructured":"(2018, October 18). Texas Instruments TMS320F2833x, TMS320F2823x Digital Signal Controllers (DSCs). Available online: http:\/\/www.ti.com\/lit\/ds\/symlink\/tms320f28335.pdf."}],"container-title":["Energies"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1073\/14\/2\/484\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:12:35Z","timestamp":1760159555000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1073\/14\/2\/484"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,1,18]]},"references-count":46,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2021,1]]}},"alternative-id":["en14020484"],"URL":"https:\/\/doi.org\/10.3390\/en14020484","relation":{},"ISSN":["1996-1073"],"issn-type":[{"value":"1996-1073","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,1,18]]}}}