Sliding-mode controller for a step up-down battery charger with a single current sensor

This paper proposes a battery charger solution based on the Zeta DC/DC converter to provide a general interface between batteries and microgrid direct current (DC) buses. This solution enables to interface batteries and DC buses with voltage conversion ratios lower, equal, and higher than one using the same components and without redesigning the control system, thus ensuring global stability. The converter controller is designed to require only the measurement of a single inductor current, instead of both inductors currents, without reducing the system flexibility and stability. The controller stability is demonstrated using the sliding-mode theory, and a design procedure for the parameters is developed to ensure a desired bus performance. Finally, simulations and experiments validate the performance of the proposed solution under realistic operation conditions.

Ferrites and Nanocrystalline Alloys Applied to DC–DC Converters for Renewable Energies

The medium frequency transformer (MFT) with nanocrystalline alloys is quintessential in new DC–DC converters involved in various front-end applications. The center piece to achieve high-performance, efficient MFTs is the core. There are various options of core materials; however, no deep information is available about which material characteristics and design procedure combo are best to get high performance MFTs while operating at maximal power density. To provide new insights about interrelation between the selection of the core material with the compliance technical specifications, differently to other proposals, this research work aims to design and build, with the same methodology, two MFT prototypes at 20 kHz, with nanocrystalline and ferrite cores, to highlight power density, and overall performance and cost, as matching design criteria. As the experimental results show, a nanocrystalline core has the highest power density (36.91 kW/L), designed at 0.8 T to obtain low losses at 20 kHz, achieving an efficiency of 99.7%. The power density in the ferrite MFT is 56.4% lower than in the nanocrystalline MFT. However, regarding construction cost, the ferrite MFT is 46% lower, providing this a trend towards low-cost DC–DC converters. Finally, high power density in MFTs increases the power density of power DC–DC converters, which have relevant applications in fuel cell-supplied systems, renewable energies, electric vehicles, and solid-state transformers.

Through the Looking Glass: A Scoping Review of Cinema and Video Therapy

Background: Cinematherapy and video treatments are artistic therapeutic techniques by which the individuals are exposed to their psycho-physical difficulties through the stories of the characters on the screen who are coping with the same issues that the patients are. Although these techniques are increasingly common within modern art therapies, there are neither comprehensive classifications of the different approaches nor agreement on their effectiveness. We performed a scoping review, describing different methodological approaches and outcome measures in cinematherapy and video treatments.Methodology: We searched articles in PubMed, PsycINFO and Google Scholar. We included: (i) articles in which subjects were treated for their difficulties with videos or films, (ii) articles written in English. Review articles and papers describing a research protocol without data collection were not included.Results: We analyzed 38 studies. Thirty-six reported a positive effect of the treatment. Seven studies used classical cinematherapy, adopting a qualitative approach to measure the therapy outcome. Thirty-one studies used different video treatments, 8 of which were defined as randomized controlled trials with specific objective therapy outcomes. Studies were mainly focused on behavioral and psychological difficulties in Autism Spectrum Disorders and Schizophrenia.Conclusion: Studies using video treatments more often rely upon structured experimental designs; on the contrary, those who used classical cinematherapy produced descriptive results. A more standardized methodological approach in terms of experimental design, procedure, and objective outcome measure is needed to provide evidence on the effectiveness of these techniques, promoting its application in the clinical field.

A New Design Procedure for Rotor Laminations of Synchronous Reluctance Machines with Fluid Shaped Barriers

A new procedure for the design and optimization of the rotor laminations of a synchronous reluctance machine is presented in this paper. The configuration of the laminations is symmetrical and contains fluid-shaped barriers. The parametrization principle is used, which executes variations in the lamination geometry by changing the position, thickness and shape of the flux barriers. Hence, the optimization procedure analyzes the various configurations through finite element simulations, by means of the communication between MATLAB and Flux 2D. In the post processing stage, the best geometry which optimizes mean torque, torque ripple, efficiency and power factor is selected. Once the best rotor configuration is defined, further investigations allow improving its performance by modifying the current angle, the stator winding and the thickness of the radial ribs.

Proposal for an IIoT Device Solution According to Industry 4.0 Concept

Today, Industrial Internet of Things (IIoT) devices are very often used to collect manufacturing process data. The integration of industrial data is increasingly being promoted by the Open Platform Communications United Architecture (OPC UA). However, available IIoT devices are limited by the features they provide; therefore, we decided to design an IIoT device taking advantage of the benefits arising from OPC UA. The design procedure was based on the creation of sequences of steps resulting in a workflow that was transformed into a finite state machine (FSM) model. The FSM model was transformed into an OPC UA object, which was implemented in the proposed IIoT. The OPC UA object makes it possible to monitor events and provide important information based on a client’s criteria. The result was the design and implementation of an IIoT device that provides improved monitoring and data acquisition, enabling improved control of the manufacturing process.

Bidirectional Interface Resonant Converter for Wide Voltage Range Storage Applications

In this paper, a bidirectional zero voltage switching (ZVS) resonant converter with narrow control frequency deviation is proposed. Wide input–output voltage range applications, such as flywheel or supercapacitors storage units are targeted. Due to symmetrical topology of resonant circuit interfaces, the proposed converter has similar behavior in bidirectional operating mode. We call it Dual Active Bridge Converter (DABC). The proposal topology of the converter is subjected to multi resonant circuits which make it necessary to study with multiscale approaches. Thus, first harmonic approximation and use of selective per unit parameters are established in (2) Methods. Then, the forward direction and backward direction of power flux exchange are detailed according to switching sequences. Switching frequency control must be completed within a narrow range. So, the frequency range deterministic parameters are emphasized in the design procedure in (3) Methods. A narrow range of switching frequency and a wide range voltage control must be ensured to suit for energy storage units, power electronic devices capabilities and electromagnetic compatibility. A 3 kW test bench is used to validate operation principles and to proof success of the developed design procedure. The interest of proposed converter is compared to other solutions from the literature in (4) Results.

2D Heat Transfer Simulation of an Injection Mold: Comparison Between ANSYS Workbench and ANSYS Mechanical APDL

The fabrication of conformal cooling channels (CCC's) has become easier and more affordable due to recent developments in additive manufacturing. The use of CCC's allows better cooling performance than the conventional (straight drilled) channels, in the injection molding process. The main reason for this is that the CCC's can follow the paths of the molded geometry, whereas the conventional channels made by conventional machining techniques are not able to do so. CCCs can help to reduce thermal strains and warpage by reducing cycle time and allowing for a more uniform temperature distribution. CCC, on the other hand, has a more complicated design procedure than traditional channels. Computer-Aided Engineering (CAE) simulations) are crucial to achieve an effective and cost-efficient design. This article focuses the comparison of two ANSYS modules, for results validation. The relative error between ANSYS Workbench and ANSYS Mechanical APDL varied from close to 0 to below 1 %, in the case of maximum temperature Tmax, and between 1.5 to 5.5 approximately, for the average temperature Tavg. It can be concluded that, for the most refined mesh studied, the results are close by the two modules. Therefore, the ANSYS module to work on should be used based on the purpose of the work, as well as the complexity of the CAD geometry.