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About

About

I have been working with INESC TEC since 2015 when I developed my Masters Thesis, entitled, "Circuit Optimization for Underwate Power Transfer", in the scope of ENDURE project.

Since September 2016 I've been a Researcher in INESC TEC, in coperation with project ENDURE.

Right now I'm a PhD candidate in Faculty of Engineering of University of Porto.

My interests are in the area of RF, Analog Electronics, Digital Electronics, Signal Processing amnog others.

Interest
Topics
Details

Details

002
Publications

2018

The successful implementation of servant leadership at a factory in the USA

Authors
Au Yong Oliveira, M; Moreira, F; Martins, J; Branco, F; Gonçalves, R;

Publication
Proceedings of the European Conference on Innovation and Entrepreneurship, ECIE

Abstract
This is a case study on leadership, a topic which has been much debated in the literature, as solutions for many diverse situations are still lacking and seem to escape us. The case describes how an entrepreneurial wood veneer factory operates, in the USA, with images included of a number of operations. The manager-owner took us on a guided tour from raw material (logs) to finished product (veneer wood). Waste is minimized at the factory in a very stream-lined operation which has a minimal amount of managers in place. Each worker is responsible for his or her job, done to perfection, as one task rolls on to the next, without stopping. The attitude of the innovative servant-type leadership in place is that "win-win" situations are better for all, and there is enough profit to go around. Servant-leadership-type leaders exist to serve employees and exercise minimal management control. At this firm there are no self-serving managers. Rather, mature and great working relationships are developed. Being greedy would mean that unions would have to be brought in. At this firm that was not necessary, by request of the employees themselves. Hispanic workers are very good and are cherished at this firm, in the heart of the USA. As leadership is dependent on culture, the discussion also includes references to cultural aspects relevant to management. The story is thus of a positive firm with positive leadership and subordinates. We conclude that employees who have emigrated from poorer countries in search of a better lifestyle may indeed make excellent workers, despite what some political leaders have announced in the media. We have found evidence that Spanish-speaking individuals do not only work well under autocratic leadership, as portrayed by the literature. Our study is thus revealing of a new cultural-type involving workers working outside their home countries. Under different leaders, in different countries and environments, certain workers are prepared to go the "extra mile" and behave in a completely different way as to what is expected from them in their home countries. This is surprising and may have important implications for multinational firms worldwide.

2017

System design for wireless powering of AUVs

Authors
Ressurreicao, T; Goncalves, F; Duarte, C; Goncalves, R; Gomes, R; Santos, R; Esteves, R; Pinto, P; Oliveira, I; Pessoa, LM;

Publication
OCEANS 2017 - Aberdeen

Abstract

2017

A study on load modulation for underwater wireless power transfer

Authors
Duarte, C; Goncalves, F; Ressurreicao, T; Gomes, R; Correia, V; Goncalves, R; Santos, R;

Publication
OCEANS 2017 - Aberdeen

Abstract

2016

An Adaptive System for Underwater Wireless Power Transfer

Authors
Goncalves, F; Pereira, A; Morais, A; Duarte, C; Gomes, R; Pessoa, LM;

Publication
2016 8TH INTERNATIONAL CONGRESS ON ULTRA MODERN TELECOMMUNICATIONS AND CONTROL SYSTEMS AND WORKSHOPS (ICUMT)

Abstract
In wireless power transfer systems, if the driver is not capable of dynamically adapt its own switching frequency, small environmental changes or even slight deviations in circuit parameters may prevent the complete system from working properly when the optimal resonance frequency moves towards new values. In this paper, we propose an adaptive system suitable for underwater wireless applications in sea water. The output voltage is regulated using the wireless power link, avoiding the need for additional wireless interfaces. Our complete system includes the power driver, coupling coils, rectifier, and two micro-controllers. The regulation is accomplished by digital load modulation, observable at the input by means of current sensing at the power supply. Experimental results demonstrate a class-D driver with a series-series resonant topology working in saline water, delivering power between 1.6 and 2.4 W. The regulated voltage is 7.5 V with error less than 7.2 % in the load range of 30 to 37 Omega and 6 to 10 V power supply variation. The switching frequency is adjusted within the range of 7 kHz deviation (-7%).

2016

A Novel Circuit Topology for Underwater Wireless Power Transfer

Authors
Goncalves, F; Duarte, C; Pessoa, LM;

Publication
2ND INTERNATIONAL CONFERENCE ON SYSTEMS INFORMATICS, MODELLING AND SIMULATION (SIMS 2016)

Abstract
This work presents a new topology for the matching networks of an underwater wireless power transfer system. A class-D driver is used in resonance at fundamental and third harmonic frequencies. The double resonance helps reducing the reverse voltage stress at the diode rectifier. We present the analytical derivation of the proposed network and demonstrate the design procedure with an example. We also show that additional degrees of freedom can be acquired with the proposed topology, which improves the design space for time-varying operation conditions of our application, such as the load changing when a battery is being recharged. The performance of our topology is compared to most conventional approaches, such as the series-series and series-parallel networks, revealing a good compromise between power delivery and efficiency across a wide load range.

Supervised
thesis

2017

Design of a Subthreshold RTC Circuit for the IoT

Author
David Rosenberger Fernandes Ferrão

Institution
UP-FEUP