Acácio Manuel Raposo Amaral
Acácio Amaral was born in Luso, Angola, in 1974. He received the Electrical Engineering diploma, the MSc degree and the Dr. Eng. degree all from the University of Coimbra, Coimbra, Portugal, in 1998, 2005 and 2011 respectively. Since 1998, he has been with the Polytechnic Institute of Coimbra, where he is currently an Assistant Reader in the Department of Informatics and Systems. His research activities include fault diagnosis and design of switch-mode power supplies, with emphasis on the consequences of aging of electrolytic capacitors, as well as the development of solutions to this problem.

Phd, Instrumentation and Control, University of Coimbra, Coimbra, Portugal, 2010.
MSc, Energy, University of Coimbra, Coimbra, Portugal, 2005.
Electrical Engineering Diploma, Automation, Electronics and Energy, University fo Coimbra, Coimbra, Portugal, 1998.
Amaral, A. M. R.: ''Sistemas Digitais – Princípios, Análise e Projectos''; Edições Sílabo (978-972-618-767-7), Lisboa, Portugal, 2014.
Amaral, A. M. R.: ''Análise de Circuitos e Dispositivos Eletrónicos''; Publindústria (978-989-723-034-9), Porto, Portugal, 2013.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Voltage Doubler for AC-DC Step-Up Linear Power Supplies: Design, Modelling and Simulation''; Acta Electrotechnica et Informatica, Vol. 16, No. 4, pp. 3-10, December, 2016.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Modeling, Simulation and Design of an AC-DC Power Supply''; International Journal on Engineering Applications, Vol. 4, No. 3, pp. 72-82, June, 2016.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using a Very Simple Capacimeter to Evaluate Aluminum Electrolytic Capacitors Health Status''; International Journal on Engineering Applications, Vol. 1, No. 4, pp. 234-240, July, 2013.
Amaral, A. M. R.; Cardoso, A. J. M.: ''On-Line Fault Detection of Aluminium Electrolytic Capacitors, in Step-Down DC-DC Converters, Using Input Current and Output Voltage Ripple''; IET Power Electronics, Vol. 5, No. 3, pp. 315-322, March, 2012.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Condition Monitoring of Electrolytic Capacitors''; International Journal of System Assurance Engineering and Management, Vol. 2, No. 4, pp. 325-332, December, 2011.
Buiatti, G. M.; Martín-Ramos, J. A.; Martínez, J. A.; Amaral, A. M. R.; Cardoso, A. J. M.: ''Online Monitoring of Capacitors in Power Converters''; Eletrônica de Potência, Vol. 16, No. 2, pp. 177-186, May, 2011.
Buiatti, G. M.; Amaral, A. M. R.; Cardoso, A. J. M.: ''A Very Simple Experimental Technique for Characterizing and Diagnosing Electrolytic Capacitors''; International Journal of Electrical Engineering Education, Vol. 48, No. 1, pp. 17-33, January, 2011.
Buiatti, G. M.; Martín-Ramos, J. A.; García, C. H. R.; Amaral, A. M. R.; Cardoso, A. J. M.: ''An Online and Noninvasive Technique for the Condition Monitoring of Capacitors in Boost Converters''; IEEE Transactions on Instrumentation and Measurement, Vol. 59, No. 8, pp. 2134-2143, August, 2010.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Simple Experimental Techniques to Characterize Capacitors in a Wide Range of Frequencies and Temperatures''; IEEE Transactions on Instrumentation and Measurement, Vol. 59, No. 5, pp. 1258-1267, May, 2010.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using Hybrid Systems Theory to Simulate the Behaviour of Step-Down DC-DC Converters''; Acta Electrotechnica et Informatica, Vol. 9, No. 4, pp. 37-41, December, 2009.
Buiatti, G. M.; Martín-Ramos, J. A.; Amaral, A. M. R.; Dworakowski, P.; Cardoso, A. J. M.: ''Condition Monitoring of Metallized Polypropylene Film Capacitors in Railway Power Trains''; IEEE Transactions on Instrumentation and Measurement, Vol. 58, No. 10, pp. 3796-3805, October, 2009.
Amaral, A. M. R.; Cardoso, A. J. M.: ''A Simple Off-Line Technique for Evaluating the Condition of Aluminum Electrolytic Capacitors''; Acta Electrotechnica et Informatica, Vol. 56, No. 8, pp. 3230-3237, August, 2009.
Amaral, A. M. R.; Cardoso, A. J. M.: ''An Economic Offline Technique for Estimating the Equivalent Circuit of Aluminum Electrolytic Capacitors''; IEEE Transactions on Instrumentation and Measurement, Vol. 57, No. 12, pp. 2697-2710, December, 2008.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Unregulated AC-DC Power Supply under Heavy Load Operation: Simulation and Design''; IEEE International Symposium on Industrial Electronics, Edinburgh, UK, pp. 913-918, June, 2017.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Estimating Aluminum Electrolytic Capacitors Condition Using a Low Frequency Transformer Together with a DC Power Supply''; IEEE International Symposium on Industrial Electronics, Bari, Italy, pp. 815-820, July, 2010.
Amaral, A. M. R.; Cardoso, A. J. M.: ''State Condition Estimation of Aluminum Electrolytic Capacitors Used on the Primary Side of ATX Power Supplies''; Annual Conference of the IEEE Industrial Electronics Society, Porto, Portugal, pp. 447-452, November, 2009.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using Input Current and Output Voltage Ripple to Estimate the Output Filter Condition of Switch Mode DC/DC Converters''; IEEE International Symposium on Diagnostics for Electrical Machines, Power Electronics & Drives, Cargèse, France, pp. 1-6, August / September, 2009.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using a Simple Charge-Discharge Circuit to Estimate Capacitors Equivalent Circuit at Their Operating Conditions''; International Conference on Power Electronics Machines and Drives, Singapore, Singapore, pp. 737-742, May, 2009.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using a Sinosoidal PWM to Estimate the ESR of Aluminum Electrolytic Capacitors''; International Conference on Power Engineering, Energy and Electrical Drives, Lisbon, Portugal, pp. 691-696, March, 2009.
Amaral, A. M. R.; Cardoso, A. J. M.: ''An Automatic Technique to Obtain the Equivalent Circuit of Aluminum Electrolytic Capacitors''; Annual Conference of the IEEE Industrial Electronics Society, Orlando, USA, pp. 539-544, November, 2008.
Amaral, A. M. R.; Cardoso, A. J. M.: ''A Non-Invasive Technique for Fault Diagnosis of SMPS''; IEEE Annual Power Electronics Specialists Conference, Rhodes, Greece, pp. 2097-2102, June, 2008.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Buck Converter Simulation Technique Based on the Fourier Transform''; International Conference on Power Electronics and Drive Systems, Bangkok, Thailand, pp. 378-385, November, 2007.
Amaral, A. M. R.; Buiatti, G. M.; Ribeiro, H.; Cardoso, A. J. M.: ''Using DFT to Obtain the Equivalent Circuit of Aluminum Electrolytic Capacitors''; International Conference on Power Electronics and Drive Systems, Bangkok, Thailand, pp. 434-438, November, 2007.
Buiatti, G. M.; Amaral, A. M. R.; Cardoso, A. J. M.: ''An Unified Method for Estimating the Parameters of Non-Isolated DC/DC Converters Using Continuous Time Models''; IEEE International Telecommunications Energy Conference, Rome, Italy, pp. 334-341, September / October, 2007.
Amaral, A. M. R.; Cardoso, A. J. M.: ''A Switch Mode Power Supply Simulation Technique Based in Laplace Transform''; IEEE International Telecommunications Energy Conference, Rome, Italy, pp. 891-898, September / October, 2007.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Fault Simulation Technique for Switch Mode Power Supplies''; International AEGEAN Conference on Electrical Machines and Power Electronics, Bodrum, Turkey, pp. 659-664, September, 2007.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using Spectral Analysis to Determine the Equivalent Circuit of the Output Filter of DC-DC Converters at Their Operating Frequency''; International AEGEAN Conference on Electrical Machines and Power Electronics, Bodrum, Turkey, pp. 671-675, September, 2007.
Buiatti, G. M.; Amaral, A. M. R.; Cardoso, A. J. M.: ''ESR Estimation Method for DC/DC Converters Through Simplified Regression Models''; IEEE Industry Applications Society Annual Meeting, New Orleans, USA, pp. 1-6, September, 2007.
Buiatti, G. M.; Amaral, A. M. R.; Cardoso, A. J. M.: ''Parameter Estimation of a DC/DC Buck Converter Using a Continuous Time Model''; European Conference on Power Electronics and Applications, Aalborg, Denmark, pp. 1-8, September, 2007.
Buiatti, G. M.; Amaral, A. M. R.; Cardoso, A. J. M.: ''An Online Technique for Estimating the Parameter of Passive Components in Non-Isolated DC/DC Converters''; IEEE International Symposium on Industrial Electronics, Vigo, Spain, pp. 606-610, June, 2007.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Theoretical Analysis of the Behaviour of a Buck Converter in Steady State Regime''; International Congress on Condition Monitoring and Diagnostic Engineering Management, Faro, Portugal, pp. 697-706, June, 2007.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using Newton-Raphson Method to Estimate the Condition of Aluminum Electrolytic Capacitors''; IEEE International Symposium on Industrial Electronics, Vigo, Spain, pp. 827-832, June, 2007.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using Fourier Analysis, to Estimate the Influence of Parasitic Elements of Aluminum Electrolytic Capacitors, in Steady Regime of Switch Mode Power Supplies''; International PCIM Conference on Power Electronics, Intelligent Motion and Power Quality, Nuremberg, Germany, pp. 1-6, May, 2007.
Amaral, A. M. R.; Cardoso, A. J. M.: ''An Experimental Technique for Estimating the ESR and Reactance Intrinsic Values of Aluminum Electrolytic Capacitors''; IEEE Instrumentation and Measurement Technology Conference, Sorrento, Italy, pp. 1820-1825, April, 2006.
Amaral, A. M. R.; Cardoso, A. J. M.: ''An Experimental Technique for Estimating the Aluminum Electrolytic Capacitor Equivalent Circuit at High Frequencies''; International Conference on Power Electronics Machines and Drives, Hong Kong, Hong Kong, pp. 86-91, December, 2005.
Amaral, A. M. R.; Cardoso, A. J. M.: ''An ESR Meter for High Frequencies''; International Conference on Power Electronics Machines and Drives, Kuala Lumpur, Malaysia, pp. 1628-1633, November / December, 2005.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using a CLC Low-Pass Filter to Reduce the Consequences of Aging in Steady-State Regime of DC-DC Converters''; European Conference on Power Electronics and Applications, Dresden, Germany, pp. 1-10, September, 2005.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Modeling and Design Step-Down DC-DC Converters Operating in DCM''; Conference on Telecommunications, Tomar, Portugal, pp. 1-4, April, 2005.
Amaral, A. M. R.; Cardoso, A. J. M.: ''The Consequences of Aging of Electrolytic Capacitors, Used in DC-DC Converters, Under Steady-State Operating Conditions''; EPE International Power Electronics and Motion Control Conference, Riga, Latvia, pp. 1-6, September, 2004.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Use of ESR to Predict Failure of Output Filtering Capacitors in Boost Converters''; IEEE International Symposium on Industrial Electronics, Ajaccio, France, pp. 1309-1314, May, 2004.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Using Output Voltage and Current to Predict Failures in Switch-Mode Power Supplies Operating in Discontinuous Mode''; International PCIM Conference on Power Electronics, Intelligent Motion and Power Quality, Nuremberg, Germany, pp. 1-6, May, 2004.
Amaral, A. M. R.; Cardoso, A. J. M.: ''ESR Influence, Under Steady-State Operating Conditions, in Buck-Boost Switch-Mode Power Supplies''; International AEGEAN Conference on Electrical Machines and Power Electronics, Istanbul, Turkey, pp. 117-122, May, 2004.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Fault Diagnosis on Switch-Mode Power Supplies Operating in Discontinuous Mode''; IEE International Conference on Power Electronics and Variable Speed Drives, Edinburgh, UK, pp. 197-202, March / April, 2004.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Diagnóstico de Avarias em Fontes de Alimentação Comutadas''; Conference on Telecommunications, Aveiro, Portugal, pp. 395-398, June, 2003.
Amaral, A. M. R.; Cardoso, A. J. M.: ''Diagnóstico de Avarias em Conversores DC-DC''; Encontro Nacional do Colégio de Engenharia Electrotécnica da Ordem dos Engenheiros, Lisboa, Portugal, pp. 1-8, May, 2003.
Amaral, A. M. R., ''Measurement Techniques for Characterizing the Aluminum Electrolytic Capacitors Equivalent Circuit (in Portugueses)'', Supervisor: Cardoso, A. J. M., University of Coimbra, Portugal, 2010.