{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,10]],"date-time":"2026-02-10T18:41:07Z","timestamp":1770748867815,"version":"3.50.0"},"reference-count":47,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2024,8,17]],"date-time":"2024-08-17T00:00:00Z","timestamp":1723852800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Portuguese Foundation for Science and Technology (FCT)","award":["UIDB\/04131\/2020"],"award-info":[{"award-number":["UIDB\/04131\/2020"]}]},{"name":"Portuguese Foundation for Science and Technology (FCT)","award":["UIDP\/04131\/2020"],"award-info":[{"award-number":["UIDP\/04131\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Electronics"],"abstract":"<jats:p>Power converters (PCs) are vital elements of critical applications, making their reliable operation crucial. Enhancing PCs\u2019 reliability can be achieved by adding intelligence to the system, enabling it to predict failures and generate early warnings before a failure occurs. In this context, intelligence is integrated into the system through preventive diagnostic algorithms (PDAs) that assess the converter condition. This article introduces a PDA designed to determine the optimal replacement timing for aluminum electrolytic capacitors (AECs) within power converters. AECs, in addition to being a fundamental component of PCs, also represent the most vulnerable element of the PCs\u2019 power section. The aging of AECs is characterized by a decrease in capacitance (C) and an increase in the equivalent series resistance (ESR). Therefore, ESR and C serve as key indicators for assessing the AECs\u2019 health status. One of the most critical functional requirements for designing a PDA is its accuracy, which can be significantly affected by transients. The solution proposed in this paper is resilient to transients, overcoming a common problem in implementing AECs\u2019 PDAs. The proposed algorithm employs discrete wavelet transform (DWT) to extract the converter signal modes. Subsequently, key characteristics of these modes are extracted, enabling the calculation of both ESR and C. Finally, by using the estimated ESR and C values, two fault indicators can be obtained that are resilient to transients. Employing a Kalman filter reduces noise and ensures the indicators\u2019 resilience to transients, making them highly effective for evaluating the AECs\u2019 health status. The proposed PDA was validated through multiple computer simulations conducted in MATLAB\/Simulink for a three-phase interleaved boost converter (3\u03d5IBC), which includes a proportional-integral (PI) controller with anti-windup capability.<\/jats:p>","DOI":"10.3390\/electronics13163265","type":"journal-article","created":{"date-parts":[[2024,8,19]],"date-time":"2024-08-19T05:19:36Z","timestamp":1724044776000},"page":"3265","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Optimized Preventive Diagnostic Algorithm for Assessing Aluminum Electrolytic Capacitor Condition Using Discrete Wavelet Transform and Kalman Filter"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8025-6898","authenticated-orcid":false,"given":"Ac\u00e1cio M. R.","family":"Amaral","sequence":"first","affiliation":[{"name":"Polytechnic Institute of Coimbra, Coimbra Institute of Engineering, Rua Pedro Nunes\u2014Quinta da Nora, 3030-199 Coimbra, Portugal"},{"name":"CISE-Electromechatronic Systems Research Centre, University of Beira Interior, Cal\u00e7ada Fonte do Lameiro, 6201-001 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7683-6897","authenticated-orcid":false,"given":"Khaled","family":"Laadjal","sequence":"additional","affiliation":[{"name":"CISE-Electromechatronic Systems Research Centre, University of Beira Interior, Cal\u00e7ada Fonte do Lameiro, 6201-001 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8737-6999","authenticated-orcid":false,"given":"Antonio J.","family":"Marques Cardoso","sequence":"additional","affiliation":[{"name":"CISE-Electromechatronic Systems Research Centre, University of Beira Interior, Cal\u00e7ada Fonte do Lameiro, 6201-001 Covilh\u00e3, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,8,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2531","DOI":"10.1109\/TPEL.2017.2690500","article-title":"Power cycling test methods for reliability assessment of power device modules in respect to temperature stress","volume":"33","author":"Choi","year":"2017","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_2","unstructured":"Cardoso, A.J.M. (2018). Diagnosis and Fault Tolerance of Electrical Machines, Power Electronics and Drives, The Institution of Engineering and Technology."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3697","DOI":"10.1109\/TPEL.2017.2763153","article-title":"A family of improved magnetically coupled impedance network boost DC\u2013DC converters","volume":"33","author":"Liu","year":"2017","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1109\/MIE.2014.2376976","article-title":"Grid-connected photovoltaic systems: An overview of recent research and emerging PV converter technology","volume":"9","author":"Kouro","year":"2015","journal-title":"IEEE Ind. Electron. Mag."},{"key":"ref_5","first-page":"5030","article-title":"A novel high step-up converter with a quasi-active switched-inductor structure for renewable energy systems","volume":"31","author":"Liu","year":"2015","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2998","DOI":"10.1109\/TIE.2013.2271602","article-title":"High-speed electric drive for exhaust gas energy recovery applications","volume":"61","author":"Crescimbini","year":"2013","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Laadjal, K., Sahraoui, M., Hammoudi, M.Y., Cardoso, A.J.M., Amaral, A.M.R., and Yahia, K. (2019, January 14\u201317). Diagnosis of Electrolytic Capacitors in Three-Phase Interleaved Boost Converters Controlled by Mixed Weighted Sensitivity H\u221e Design Control. Proceedings of the IECON 2019-45th Annual Conference of the IEEE Industrial Electronics Society, Lisbon, Portugal.","DOI":"10.1109\/IECON.2019.8927086"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"7783","DOI":"10.1109\/TPEL.2016.2637370","article-title":"Dynamic response improvements of parallel-connected bidirectional DC\u2013DC converters for electrical drive powered by low-voltage battery employing optimized feedforward control","volume":"32","author":"Sha","year":"2016","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"4775","DOI":"10.1109\/TIA.2018.2845889","article-title":"Online condition monitoring system for DC-link capacitor in industrial power converters","volume":"54","author":"Sundararajan","year":"2018","journal-title":"IEEE Trans. Ind. Appl."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"5283","DOI":"10.1109\/TPEL.2017.2736162","article-title":"Quasi-online technique for health monitoring of capacitor in single-phase solar inverter","volume":"33","author":"Agarwal","year":"2017","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"4976","DOI":"10.1109\/TIA.2016.2591906","article-title":"A review of the condition monitoring of capacitors in power electronic converters","volume":"52","author":"Soliman","year":"2016","journal-title":"IEEE Trans. Ind. Appl."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1258","DOI":"10.1109\/TIM.2009.2038018","article-title":"Simple experimental techniques to characterize capacitors in a wide range of frequencies and temperatures","volume":"59","author":"Amaral","year":"2010","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1126","DOI":"10.1109\/TPEL.2014.2339374","article-title":"Deterioration monitoring of DC-link capacitors in AC machine drives by current injection","volume":"30","author":"Nguyen","year":"2014","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Amaral, A.M.R., Laadjal, K., and Cardoso, A.J.M. (2023). Advanced fault-detection technique for dc-link aluminum electrolytic capacitors based on a random forest classifier. Electronics, 12.","DOI":"10.3390\/electronics12122572"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4340","DOI":"10.1109\/JESTPE.2023.3270428","article-title":"Design and analysis of universal natural fault-tolerant SVPWM strategy with simplified fault diagnosis for multiphase motor drives","volume":"11","author":"Yang","year":"2023","journal-title":"IEEE J. Emerg. Sel. Top. Power Electron."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1296","DOI":"10.1109\/TIE.2018.2835393","article-title":"A VEN condition monitoring method of DC-link capacitors for power converters","volume":"66","author":"Wu","year":"2018","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1109\/MEI.2016.7414227","article-title":"Electrolytic capacitors from the postwar period to the present","volume":"32","author":"Both","year":"2016","journal-title":"IEEE Electr. Insul. Mag."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Khan, S.A., Khera, N., Islam, T., and Agarwala, A.K. (2014, January 6\u20138). An online method for condition based maintenance of aluminum electrolytic capacitors. Proceedings of the 2014 Recent Advances in Engineering and Computational Sciences (RAECS), Chandigarh, India.","DOI":"10.1109\/RAECS.2014.6799592"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1441","DOI":"10.1109\/TIA.2011.2124436","article-title":"An industry-based survey of reliability in power electronic converters","volume":"47","author":"Yang","year":"2011","journal-title":"IEEE Trans. Ind. Appl."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"591","DOI":"10.1109\/TPEL.2012.2192503","article-title":"Survey on reliability of power electronic systems","volume":"28","author":"Song","year":"2012","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2734","DOI":"10.1109\/TPEL.2010.2049377","article-title":"Condition monitoring for device reliability in power electronic converters: A review","volume":"25","author":"Yang","year":"2010","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"493","DOI":"10.1109\/TPEL.2010.2059713","article-title":"Life-cycle monitoring and voltage-managing unit for DC-link electrolytic capacitors in PWM converters","volume":"26","author":"Vogelsberger","year":"2010","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2134","DOI":"10.1109\/TIM.2009.2032960","article-title":"An online and noninvasive technique for the condition monitoring of capacitors in boost converters","volume":"59","author":"Buiatti","year":"2009","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Yu, Y., Zhou, T., Zhu, M., and Xu, D. (2012, January 8\u201310). Fault diagnosis and life prediction of dc-link aluminum electrolytic capacitors used in three-phase ac\/dc\/ac converters. Proceedings of the 2012 Second International Conference on Instrumentation, Measurement, Computer, Communication and Control, Harbin, China.","DOI":"10.1109\/IMCCC.2012.199"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1049\/iet-pel.2011.0163","article-title":"On-line fault detection of aluminium electrolytic capacitors, in step-down DC\u2013DC converters, using input current and output voltage ripple","volume":"5","author":"Amaral","year":"2012","journal-title":"IET Power Electron."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"5657","DOI":"10.1109\/TIE.2017.2674598","article-title":"Low-frequency impedance monitoring and corresponding failure criteria for aluminum electrolytic capacitors","volume":"64","author":"Ahmad","year":"2017","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"3224","DOI":"10.1109\/TIA.2016.2550527","article-title":"Capacitor aging detection in a DC\u2013DC converter output stage","volume":"52","author":"Hannonen","year":"2016","journal-title":"IEEE Trans. Ind. Appl."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"5748","DOI":"10.1109\/TPEL.2018.2868564","article-title":"A noninvasive online monitoring method of output capacitor\u2019s C and ESR for DCM flyback converter","volume":"34","author":"Yao","year":"2018","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3190","DOI":"10.1109\/TIM.2017.2749838","article-title":"Noninvasive online condition monitoring of output capacitor\u2019s ESR and C for a flyback converter","volume":"66","author":"Yao","year":"2017","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Prasanth, S., Halick, M., Sathik, M., Sasongko, F., Seng, T.C., Yaxin, P., and Simanjorang, R. (2018, January 20\u201324). Condition Monitoring of Electrolytic Capacitor based on ESR Estimation and Thermal Impedance model using Improved Power Loss Computation. Proceedings of the 2018 International Power Electronics Conference (IPEC-Niigata 2018-ECCE Asia), Niigata, Japan.","DOI":"10.23919\/IPEC.2018.8507747"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Meng, J., Chen, E.-X., and Ge, S.-J. (2018, January 4\u20137). Online E-cap condition monitoring method based on state observer. Proceedings of the 2018 IEEE International Power Electronics and Application Conference and Exposition (PEAC), Shenzhen, China.","DOI":"10.1109\/PEAC.2018.8590416"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"10153","DOI":"10.1109\/TPEL.2018.2890617","article-title":"An online ESR estimation method for output capacitor of boost converter","volume":"34","author":"Ren","year":"2019","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"5944","DOI":"10.1109\/TPEL.2015.2496267","article-title":"An online monitoring scheme of DC-link capacitor\u2019s ESR and C for a boost PFC converter","volume":"31","author":"Yao","year":"2015","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"3230","DOI":"10.1109\/TIE.2009.2022077","article-title":"A simple offline technique for evaluating the condition of aluminum\u2013electrolytic\u2013capacitors","volume":"56","author":"Amaral","year":"2009","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Amaral, A.M.R., and Cardoso, A.J.M. (2022). Simulation tool to evaluate fault diagnosis techniques for DC-DC converters. Symmetry, 14.","DOI":"10.3390\/sym14091886"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"7824","DOI":"10.1109\/TPEL.2016.2632118","article-title":"A unified analysis of the fault tolerance capability in six-phase induction motor drives","volume":"32","author":"Munim","year":"2016","journal-title":"IEEE Trans. Power Electron."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"4505811","DOI":"10.1109\/TGRS.2024.3395902","article-title":"Time-Reassigning Transform for the Time-Frequency Analysis of Seismic Data","volume":"62","author":"Song","year":"2024","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"4080","DOI":"10.1109\/TIE.2017.2758745","article-title":"Short-time Fourier transform based transient analysis of VSC interfaced point-to-point DC system","volume":"65","author":"Satpathi","year":"2017","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"4320","DOI":"10.1109\/JSYST.2020.2984132","article-title":"Discrete-wavelet-transform and stockwell-transform-based statistical parameters estimation for fault analysis in grid-connected wind power system","volume":"14","author":"Mukherjee","year":"2020","journal-title":"IEEE Syst. J."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1242","DOI":"10.1109\/TPWRD.2012.2234942","article-title":"Obtaining the electrical impedance using wavelet transform from the time response","volume":"28","author":"Silva","year":"2013","journal-title":"IEEE Trans. Power Deliv."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"58869","DOI":"10.1109\/ACCESS.2022.3179517","article-title":"A review of wavelet analysis and its applications: Challenges and opportunities","volume":"10","author":"Guo","year":"2022","journal-title":"IEEE Access"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1295","DOI":"10.1109\/TSP.2022.3152607","article-title":"General Parameterized Fourier Transform: A Unified Framework for the Fourier, Laplace, Mellin and $ Z $ Transforms","volume":"70","author":"Singh","year":"2022","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1150","DOI":"10.1109\/TVT.2015.2414936","article-title":"Discrete wavelet transform-based feature extraction of experimental voltage signal for Li-ion cell consistency","volume":"65","author":"Kim","year":"2015","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"596","DOI":"10.1109\/JSEN.2023.3334819","article-title":"Seismic Random Noise Attenuation using Optimal Empirical Wavelet Transform with a New Wavelet Thresholding Technique","volume":"24","author":"Geetha","year":"2023","journal-title":"IEEE Sens. J."},{"key":"ref_45","unstructured":"(2024, July 20). Aluminum Electrolytic Capacitor Application Guide, Application Guide, Cornell Dubilier. Available online: https:\/\/www.cde.com\/resources\/technical-papers\/AEappGuide.pdf."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1007\/s13198-012-0085-x","article-title":"Condition monitoring of electrolytic capacitors","volume":"2","author":"Amaral","year":"2011","journal-title":"Int. J. Syst. Assur. Eng. Manag."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Florin, F.A., Sever, P.S., and Vlad, B. (2024, January 15\u201319). Evaluating the Performance of Measurements Systems Using Data Processing Methods Based on Kalman Filter. Proceedings of the 2024 47th International Spring Seminar on Electronics Technology (ISSE), Prague, Czech Republic.","DOI":"10.1109\/ISSE61612.2024.10604275"}],"container-title":["Electronics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-9292\/13\/16\/3265\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T15:38:11Z","timestamp":1760110691000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-9292\/13\/16\/3265"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,8,17]]},"references-count":47,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2024,8]]}},"alternative-id":["electronics13163265"],"URL":"https:\/\/doi.org\/10.3390\/electronics13163265","relation":{},"ISSN":["2079-9292"],"issn-type":[{"value":"2079-9292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,8,17]]}}}