Over the past few years, interest and research in wireless power transfer (WPT) have been rapidly incrementing, and as an effect, this is a remarkable technology in many electronic devices, electric vehicles and medical devices. However, most of the applications have been limited to very close distances because of efficiency concerns. Even though the inductive power transfer technique is becoming relatively mature, it has not shown near-field results more than a few metres away transmission. This review is focused on two fundamental aspects: the power efficiency and the transmission distance in WPT systems. Introducing the principles and the boundaries, scientific articles will be reviewed and discussed in terms of their methods and respective challenges. This paper also shows more important results in efficiency and distance obtained, clearly explaining the theory behind and obstacles to overcome. Furthermore, an overlook in other aspects and the latest research studies for this technology will be given. Moreover, new issues have been raised including safety and security.
Based on Gauss’ law for the electric field, new formulas were deduced, that enable for the first time the writing of an analytical formula of the built-in potential of implanted and diffused semiconductor junctions. Consequently, in this work is devised a measurement technique for the built-in potential of such junctions. Such measurement is useful because new semiconductor materials besides silicon are more and more used today, like silicon-carbide (SiC) and gallium-nitride (GaN), which have larger bandgap and junction built-in potential. Finding the built-in potential helps adjusting the computer assisted design (CAD) tools and validates the simulation of such wide-bandgap devices.
In this work, we present a new fuzzy second-order sliding mode controller (FSOSMC) for wind power transformation system based on a doubly-fed induction generator (DFIG) using intelligent space vector pulse width modulation (SVPWM). The proposed command strategy combines a fuzzy logic and a second order sliding mode control (SOSMC) for the DFIG command. This strategy presents attractive features such as chattering-free, compared to the conventional first and second order sliding mode techniques. The use of this method provides very satisfactory performance for the DFIG command. The effectiveness of this command strategy is proven through the simulation results.
Gustavo Gonçalves Coelho, Eric Henrique Moretti and João Paulo Coelho
Automation of industrial activities aims to improve the efficiency of the productive processes while reducing costs and increasing safety. In industrial laundries, detergent management is a key factor that can lead to severe economic and environmental impacts if left uncontrolled. This paper documents the solution devised for an integrated detergent control and supervision system based on Internet-of Things paradigms. This solution follows from a problem put forward by the laundry services of Santa Casa da Misericórdia de Bragança, located in Portugal, to the Polytechnic Institute of Bragança. In order to keep track of the detergent in a centralised dispensing system, a Wi-Fi based measurement system was developed which enables real-time monitoring of the chemicals level. In order to facilitate the physical installation of the developed hardware, a custom-made enclosure was designed and 3D printed. The acquired data is then sent to a database connected to a data processing web-based platform which is responsible for the analytics.
Eric Henrique Moretti, Gustavo Gonçalves Coelho and João Paulo Coelho
Development of increasingly efficient production methods is a competiveness driving factor for any company. Today, many of these improvements include the integration of technology-based solutions into processes traditionally operated by humans. In this context, the present work aims to report the controller performance of a prototype developed for semi-automatic sewing stations. This project was fostered by “Factory Play”, a Portuguese company that produces inflatable structures, under the technical supervision of the Polytechnic Institute of Bragança. At the present time, the sewing station travel speed is regulated by an embedded PID controller that has been previously tuned using classical methods. However, even if the overall performance is currently acceptable, additional experiments were made regarding the use of evolutionary based algorithms to attain a better dynamic response and flexibility. This article present the results obtained using those methods where it is possible to confirm that the use of evolutionary algorithm will simplify the design process while consistently leading to a suitable solution.
Machine-learning techniques allow to extract information from electroencephalographic (EEG) recordings of brain activity. By processing the measurement results of a publicly available EEG dataset, we were able to obtain information that could be used to train a feedforward neural network to classify two types of volunteer activities with high efficiency.
At present the processing power of the digital electronic chip is enormous and that has been possible because of the continuous improvement of the design methodology and fabrication technology. So, the data processing capability of the chip is increased significantly. Data processing in the electronic chip means the arithmetic operation on that data. For that reason, ALU is present in any processor. Full adder is one of the critical components of arithmetic unit. Improvement of the full adder is necessary for improving the computational performance of a chip. In order to design an efficient full adder, designer should choose an appropriate logic style. In this research, two new model of full-adder circuits are designed and analyzed using Pass Transistor logic in order to reduce power consumption and increase operational speed. The first proposed adder consists of 8 transistors and the second one consists of 10 transistors. LTSPICE is employed for simulating the proposed circuits using16nm low power high-k strained silicon transistor model. The overall performance of the proposed adder circuits and comparative results demonstrate the superiority of the proposed model.
In order to be able to realize out the mixing detection or harmonic generation functions, a non-linear circuit is necessary for different existing devices and for performing these types of operation, in the submillimetric and / or far-infrared domains (10 μm ≤ λ ≤ 1 mm), the spectral margin covered by this radiation ranging from 300 GHz to 30 THz. In these frequency domains, non-linear point devices are often used, unlike the optical domain where massive devices are widely used, among them the Josephson Junction (JJ) is mainly used in the case where low noise is desired. This paper present electrical characteristic of Josephson Junction (JJ) using Approximation in the sense of Least Squares, for different value of Cj, T, Rj.
This paper is a review of the way in which the high-quality factor antennas can be used to integrate the VHF and HF car’s antennas in one device. The usage of the citizen band (CB) antennas in an HF band extends the environmental awareness of the driver and could increase the safety of the traffic. Usually, the citizen band transceiver with its antenna isn’t installed in a brand new car but the FM radio receiver it is. The main constraints that are related to the size difference between the two antennas (in FM and CB) make the main car manufacturers let the matter regarding the CB usage, open, at the choice of the buyer. The paper analyzes the technological advancements in the field and investigates some alternatives to the issue that will allow an opening through a single antenna usage for both radio bands.
This paper presents a method to increase the detection range for RFID readers in the UHF radio band. The design is following especially the ISO 18000-6C standardization demands for the UHF band, operating from 865 to 868 MHz in Europe and from 902 to 928 MHz in North America. These regulations are allowing the RFID tags to operate near the metallic surfaces and in a wider range than its counterparts at lower frequencies. The paper highlights the advantages offered by the array antenna, especially by the beamforming to increase the reader surveillance zone. The paper describes some additional techniques that are allowing the usage of the circular polarization to increase the reader sensing range and to improuve detection. The design starts with simulation and optimization using HFSS and ends with the measurements that validate the simulation results.