MnZn-based ferrite materials like the EPCOS N87 or K2004 are commonly used as magnetic cores in inductive power transfer (IPT) applications. However, the performance and the reliability of IPT ...systems are limited by ferrite's intrinsic brittleness and low flux density saturation point. In this article, a study of nanocrystalline-ribbon-based magnetic cores for IPT applications is presented. Finite element method (FEM) simulations and experimental validations are used to compare both materials. The design of ultrathin laminated cores such as nanocrystalline ribbons for IPT systems is presented. Compared to ferrite, nanocrystalline ribbon is mechanically more robust; it has a higher magnetic permeability and a higher saturation point. Results show that nanocrystalline ribbon cores achieve more than a <inline-formula><tex-math notation="LaTeX">\text{50}\%</tex-math></inline-formula> volume reduction when used in IPT pads. This is due to nanocrystalline's high saturation point. However, a compromise arises as the total power loss increases due to the induced eddy currents in the core. The reduction of efficiency can be mitigated by special geometrical designs of the nanocrystalline ribbon cores. A 6.6-kW IPT system has been built for experimental validation of the design methodology.
With the rapid development of wireless power transfer (WPT), the self-resonant WPT system without using additional compensation capacitors has attracted attention. However, most of reported ...self-resonant WPT systems have low power transfer (less than 100 W) and high operating frequencies at megahertz. In this article, four multilayer, self-resonant WPT coil pads with different dielectrics are designed and experimentally validated. The aim of this article is to increase the power rating and decrease the operating frequency for capacitor-free WPT system compared to reported systems used in consumer electronics. Analysis of integrated compensation capacitance, inductance, and parasitic capacitance of the coil is provided. Finite-element analysis is used to evaluate four dielectric materials, mica, polypropylene, polyimide, and fiberglass. An experimental setup has been developed, which can achieve more than 360-W power transfer for a 120 mm air gap with an efficiency of 82% and an operating frequency of near 80 kHz.
Deadbeat-direct torque and flux control is a flux-observer-based high-bandwidth digital closed-loop torque control law that achieves the commanded torque at the end of each switching period. When ...flux estimation is accurate, instantaneous torque is fed back and undesirable pulsating torque is inherently minimized. This study presents real-time flux-observer-based torque ripple estimation of a highly nonlinear synchronous reluctance machine. Saturation and cross saturation are incorporated directly into the control law, and are considered in each switching period. Deadbeat torque response and torque ripple reduction is demonstrated experimentally. Finite element method simulations validate the torque ripple minimization.
In this paper, a new temperature observer topology is presented which overcomes the shortcomings of previous ones and achieves a higher accuracy, and a more robust disturbance rejection. It makes use ...of the Gopinath-style flux observer and combines a lumped-parameter thermal network operating at low speeds and a flux-based permanent magnet temperature observer operating at medium and high speeds. Simulation and experimental results on a 50 kW permanent magnet motor show a performance enhancement over standard topologies; particularly, a superior disturbance rejection to voltage estimation errors. A detailed analysis of the optimal controller tuning is also presented. Furthermore, a Kalman filter is incorporated to account for sensor noise and model uncertainties. Experimental results show an effective fusion of independent temperature estimation methods leading to a superior accuracy compared to the previously investigated approaches. Moreover, the Kalman filter-based fusion offers the capability of detecting temperature-related system failures, e.g., cooling circuit malfunctions.
La literatura en negocios y mercadeo ha señalado la importancia de investigar el concepto de sostenibilidad desde diferentes perspectivas, siendo la industria de la moda un ámbito de especial interés ...debido a su constante desarrollo, gran tamaño, y amplio involucramiento con el consumidor. Por lo anterior, el objetivo de esta investigación fue analizar tanto los factores de comercialización de la moda sostenible por parte de empresarios, y los factores motivacionales de su consumo por parte del consumidor, considerándose esta investigación un primer acercamiento al tema. Se ha seguido una investigación mixta combinando una fase cualitativa dirigida a empresarios logrando 12 entrevistas y una fase cuantitativa dirigida a los consumidores de moda sostenible consiguiendo 385 encuestas online. Los resultados se organizan en dos fases complementarias, de acuerdo con el objetivo y perspectiva motivacional estudiada. Los hallazgos sugieren que los empresarios deciden fabricar y comercializar prendas de vestir sostenibles debido a valores aspiracionales de contribuir a la sociedad, mientras que los consumidores deciden comprar y usar prendas de vestir sostenibles por razones simbólicas para cuidar y aportar a la sociedad y al planeta.
Nanocrystalline alloys have been recently considered as an alternative to ferrite as the magnetic cores in inductive power transfer systems due to their superior properties such as higher saturation ...flux density and permeability. They are also less brittle, more stable to temperature variations, and have a higher thermal conductivity. To take advantage of these properties, a dedicated design approach is required, different from the one used for ferrite cores. In this article, special considerations and methods for the design of nanocrystalline ribbon cores are presented. An 11.1-kW pad is designed and compared with one with identical ferrite cores. Results show that IPT pads with nanocrystalline ribbon cores yield superior magnetic performance in terms of inductances and coupling factors. Higher efficiency and power density were also achieved with the proposed design. Furthermore, compared to ferrite-based pads, they showed lower leakage flux and a superior stability to temperature variations.
In this contribution, a feasibility analysis of using nanocrystalline ribbon as a replacement for ferrite in inductive power charger's cores is presented. As well, a method for the analysis of core ...loss of high frequency magnetic cores with anisotropic conductivity is analised. FEM simulations and experimental validations are used to compare both materials as cores of inductive pads. Despite nanocrystalline's superior magnetic properties, both materials yield similar coupling factors and in-ductances. The improvement in M achieved with nanocrystalline cores is ∼ 2.8%. Eddy current losses redefine the flux distribution in nanocrystalline cores and increase the overall core losses. About 20% higher core losses are expected. However, results suggest that due to the higher saturation point of nanocrystalline, a core miniaturization can be effectively achieved.
La experiencia que tienen las personas frente a la publicidad en redes sociales es un tópico de interés en la gestión de marketing digital; en este sentido, el concepto de brand experience ofrece una ...alternativa para mejorar la comprensión de las dimensiones críticas que optimizan los vínculos y atención de los consumidores hacia las marcas que deciden hacer publicidad. El objetivo de esta investigación fue analizar los componentes evaluativos de la experiencia frente a la publicidad de ropa en la red social Instagram. Se desarrolló una investigación de naturaleza cuantitativa utilizando como técnica de recolección de datos, la encuesta online. Los resultados, a través de análisis descriptivo y solución factorial, revelan tres factores constitutivos de la experiencia. Finalmente, discutimos el dominio del componente comportamental, seguido por el componente afectivo y a su vez, el componente intelectual de la experiencia de marca en Instagram.
Deadbeat-control is a well-established control technique that uses the inverse machine model to determine the voltage commands required to achieve the desired torque and flux commands. Its classic ...implementation requires solving a quadratic equation with an extensive number of terms. Moreover, it can be only solved in the dq-reference frame. In this paper, two novel implementations are presented. The first methodology, in the dq-reference frame, reduces the algorithm's complexity and computation time. Moreover, it is immune to estimation errors of the permanent magnet flux. A second methodology based on the flux vector orientation is also presented. As opposed to the classic implementation, the proposed method does not require solving a quadratic equation; this reduces its complexity and computation time. Furthermore, the proposed methodology can be solved both in the dq and αβ frames since it relies only on the stator flux's magnitude and angle. Up to date and to the best of the author's knowledge, DB-DTFC in the stationary frame has not been presented before for salient machines. DB-DTFC in the stationary frame reduces the reliance on the position observer and facilitates the implementation of overmodulation techniques and six-step operation. The proposed methodology can operate in the MTPF line without any adjustments and it shows an adequate dynamic performance. Simulation and experimental results validate the methodologies. Caveats regarding their implementation are also discussed.
The elastic modulus of a deposit ( E d) can be obtained by monitoring the temperature (∆ T) and curvature (∆ k) of a one-side coated long plate, namely, a one-dimensional (1D) deformation model. The ...aim of this research is to design an experimental setup that proves whether a 1D deformation model can be scaled for complex geometries. The setup includes a laser displacement sensor mounted on a robotic arm capable of scanning a specimen surface and measuring its deformation. The reproducibility of the results is verified by comparing the present results with Stony Brook University Laboratory's results. The ∆ k-∆ T slope error is less than 8%, and the E d estimation error is close to 2%. These values reveal the repeatability of the experiments. Several samples fabricated with aluminum as the substrate and 100MXC nanowire (Fe and Cr alloy) as the deposit are analyzed and compared with those in finite element (FE) simulations. The linear elastic behavior of 1D (flat long plate) and 2D (squared plate) specimens during heating/cooling cycles is demonstrated by the high linearity of all ∆ k-∆ T curves (over 97%). The E d values are approximately equal for 1D and 2D analyses, with a median of 96 GPa and standard deviation of 2 GPa. The correspondence between the experimental and simulated results for the 1D and 2D specimens reveals that deformation and thermal stress in coated specimens can be predicted regardless of specimen geometry through FE modeling and by using the experimental value of E d. An example of a turbine-blade-shaped substrate is presented to validate the approach.
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