scholarly journals An Experimental Comparison of the Effects of Nanocrystalline Core Geometry on the Performance and Dispersion Inductance of the MFTs Applied in DC-DC Converters

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 453
Author(s):  
Dante Ruiz-Robles ◽  
Carlos Figueroa-Barrera ◽  
Edgar L. Moreno-Goytia ◽  
Vicente Venegas-Rebollar
Keyword(s):  
Power Density ◽  
High Efficiency ◽  
Experimental Comparison ◽  
Experimental Development ◽  
Solid State Transformers ◽  
The Core ◽  
New Information ◽  
Core Losses ◽  
Analysis Design ◽  
And Performance

The development of Medium Frequency Transformers (MFTs) from a novel perspective is essential for the advancement of today´s various relevant applications such as the emerging solid-state transformers, along with interfaces for the interconnection of photovoltaic parks and electric vehicles. The analysis, design and implementation of MFTs pursuing the achievement of characteristics such as high power density, high efficiency, and a specific dispersion inductance is a key goal for designers. There are several parameters and design methods that influence the final performance of an MFT, such as the geometry and material of the core. The advantages/disadvantages of each material/geometry combination, about the dispersion inductance for instance, are not well known, even considering a single material but various geometries. This paper presents the analysis, design and experimental development of three nanocrystalline-core MFTs, each one with a different core geometry (toroidal, type CC and shell-type). The purpose of this work is to evaluate and compare the most favourable characteristics and performance of each type of geometry, tested at 5 kHz and 1.75 kVA. The cases studied, in simulation and experimentation with scaled prototypes, focus on evaluating the power density, the core losses, the winding losses, the geometric dimensions, and the dispersion inductance obtained in each MFT, as well as its performances operating with sinusoidal and square waveforms. The results show that: 1) the toroid core has higher efficiency; 2) the shell core has the lowest dispersion inductance and is easier to build, and 3) the CC type has the highest dispersion inductance. This new information is a step to further understand how to get more controllable, more efficient MFTS, with a higher power density and lower cost, depending on the intended application of cutting-edge DC-DC DAB-type converters.

scholarly journals Comparison and assessment of a different steel materials based on core losses reduction for three-phase induction motor

2021 ◽  
Vol 12 (1) ◽  
pp. 29
Author(s):  
Yaser Atta Yassin ◽  
Ali Nasser Hussain ◽  
Nagham Yassin Ahmed
Keyword(s):  
Induction Motor ◽  
Core Loss ◽  
Low Carbon Steel ◽  
Core Material ◽  
Low Carbon ◽  
The Core ◽  
Steel Material ◽  
Three Phase ◽  
Core Losses ◽  
And Performance

This paper presents a core losses and performance calculation with different type of steel materials in the core design for three-phase induction motor by using "ANSYS Maxwell" program in order to identify the core material that provides the most effective performance by iron losses reduction. The coefficients of core losses are calculated from the magnetization curve and core Loss curve based on the on steel material databases. Although the difficult to obtain because of the little of existing information. Results show the capability of the proposed Cobalt steel (Hiperco 50) to achieve the significant losses reduction in comparison to the Electrical Steel NGO–AK Steel’s M-19 and Low Carbon Steel-SAE1020.

Epstein frame investigation on soft magnetic properties of Fe-based amorphous strips

2021 ◽  
Vol 63 (10) ◽  
pp. 604-609
Author(s):  
Yanxing Xing ◽  
Shaoxiong Zhou ◽  
Wenzhi Chen ◽  
Bangshao Dong ◽  
Yaqiang Dong ◽  
...  
Keyword(s):  
High Efficiency ◽  
Core Loss ◽  
Core Material ◽  
Test Results ◽  
The Core ◽  
Distribution Transformers ◽  
Core Losses ◽  
Power Frequency ◽  
Field Annealing ◽  
Frame Method

Fe-based amorphous strip (AM strip) is a core material for high-efficiency distribution transformers and contributes to saving energy loss in electricity distribution. The core loss and apparent power for 2605SA1 amorphous strips at power frequency are studied using the Epstein frame method. Longitudinal magnetic field annealing and the influence of measuring modes on test results are investigated in detail. Improved test efficiency and higher accuracy in test results for amorphous ribbons are demonstrated and it is found that the number of strips and the lap joint methods affect the test results greatly. The waveform of the secondary induction voltage becomes sinusoidal with the increase of strip number. The values of core loss and apparent power become stable once the total number of strips is larger than 20. The coefficient of eddy current loss (e) also affects the correction of testing core losses. The test results could be improved at a smaller value of e when the waveform of the secondary induction voltage becomes deformed from sinusoidal due to a lower number of strips (below 20). The measured results were found to be reproducible when the strip number of each layer was one or two. However, the core loss and the apparent power increased along with the increase in the number of strips in each layer. Moreover, demagnetisation showed no effects on the test results when using the Epstein frame method.

scholarly journals Design and Prototyping Medium-Frequency Transformers Featuring a Nanocrystalline Core for DC–DC Converters

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2081 ◽  
Author(s):  
Dante Ruiz-Robles ◽  
Vicente Venegas-Rebollar ◽  
Adolfo Anaya-Ruiz ◽  
Edgar Moreno-Goytia ◽  
Juan Rodríguez-Rodríguez
Keyword(s):  
Power Plants ◽  
Medium Frequency ◽  
Solid State Transformers ◽  
Design Procedures ◽  
The Core ◽  
Dual Active Bridge ◽  
Product Technique ◽  
Core Losses ◽  
Full Analysis ◽  
Area Product

Medium frequency transformers (MFTs) are a key component of DC–DC dual active bridge (DAB)-type converters. These technologies are becoming a quintessential part of renewable energy solutions, such as photovoltaic systems and wind energy power plants, as well as in modern power grid interfaces functioning as solid-state transformers in smart-grid environments. The weight and physical dimensions of an MFT are key data for the design of these devices. The size of an MFT is reduced by increasing its operating frequency. This reduction implicates higher power density through the transformer windings, as well as other design requirements distinct to those used for conventional 60/50 Hz transformers; therefore, new MFT design procedures are needed. This paper introduces a novel methodology for designing MFTs, using nanocrystalline cores, and tests it using an MFT–DAB lab prototype. Different to other MFT design procedures, this new design approach uses a modified version of the area-product technique, which consists of smartly modifying the core losses computation, and includes nanocrystalline cores. The core losses computation is supported by a full analysis of the dispersion inductance. For purposes of validation, a model MFT connected to a DAB converter is simulated in Matlab-Simulink (The MathWorks, v2014a, Mexico City, Mexico). In addition, a MFT–DAB lab prototype (1 kVA at 5 kHz) is implemented to experimentally probe further the validity of the methodology just proposed. These results demonstrate that the analytic calculations results match those obtained from simulations and lab experiments. In all cases, the efficiency of the MFT is greater than 99%.

scholarly journals Power Density Maximization in Medium Frequency Transformers by Using Their Maximum Flux Density for DC–DC Converters

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 470
Author(s):  
Dante Ruiz-Robles ◽  
Edgar L. Moreno-Goytia ◽  
Vicente Venegas-Rebollar ◽  
Nadia M. Salgado-Herrera
Keyword(s):  
Flux Density ◽  
Power Density ◽  
High Performance ◽  
High Efficiency ◽  
Electrical Power ◽  
Power Grids ◽  
Medium Frequency ◽  
Maximum Flux ◽  
Conventional Procedure ◽  
Core Losses

The medium frequency transformer (MTF) is a key component of various new DC–DC converters that are designed for applications in modern electrical power grids at medium and high voltage. To attain the high performance that are necessary for targeting these applications, MFTs should have high power density and high efficiency as characteristics. For this endeavor, newly designed MFT procedures, which also take advantages of new core materials, are under investigation. Differently to other design proposals, most of which use conventional transformer design procedures based on equating core losses to copper conduction losses, in this paper, an MTF with a nanocrystalline (VITROPERM 500F) core is designed with a new procedure that is oriented in aiming the maximum flux density (Bmax). The characteristics of the MFTs that are obtained by using this procedure are compared with those of the MFTFs that are designed with a conventional procedure. The results show that by using the proposed technique, we get a 25% reduction in the winding size, a higher power density, and a lower MTF building cost while maintaining a high efficiency (>98%). The design methodology is developed through a rigorous mathematical analysis that is verified with computer simulations in Matlab-Simulink and validated with experimental results from two MTF laboratory prototypes designed at a flux density of 0.9 T (75% Bmax) and 1.2 T (Bmax).

Investigation of the Structure and Magnetic Properties of Bulk Amorphous FeCoYB Alloy

2017 ◽  
Vol 68 (9) ◽  
pp. 2162-2165 ◽  
Author(s):  
Katarzyna Bloch ◽  
Mihail Aurel Titu ◽  
Andrei Victor Sandu
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Hyperfine Field ◽  
Irreversible Processes ◽  
Magnetization Process ◽  
Casting Method ◽  
The Core ◽  
Injection Casting ◽  
Core Losses ◽  
Microstructural Studies

The paper presents the results of structural and microstructural studies for the bulk Fe65Co10Y5B20 and Fe63Co10Y7B20 alloys. All the rods obtained by the injection casting method were fully amorphous. It was found on the basis of analysis of distribution of hyperfine field induction that the samples of Fe65Co10Y5B20 alloy are characterised with greater atomic packing density. Addition of Y to the bulk amorphous Fe65Co10Y5B20 alloy leads to the decrease of the average induction of hyperfine field value. In a strong magnetic field (i.e. greater than 0.4HC), during the magnetization process of the alloys, where irreversible processes take place, the core losses associated with magnetization and de-magnetization were investigated.

scholarly journals ZVS Auxiliary Circuit for a 10 kW Unregulated LLC Full-Bridge Operating at Resonant Frequency for Aircraft Application

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1850 ◽  
Author(s):  
Yann E. Bouvier ◽  
Diego Serrano ◽  
Uroš Borović ◽  
Gonzalo Moreno ◽  
Miroslav Vasić ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Power Density ◽  
High Efficiency ◽  
Harmonic Approximation ◽  
Maximum Efficiency ◽  
Voltage Gain ◽  
Load Range ◽  
Transition Analysis ◽  
Aircraft Application ◽  
Auxiliary Circuit

In modern aircraft designs, following the More Electrical Aircraft (MEA) philosophy, there is a growing need for new high-power converters. In this context, innovative solutions to provide high efficiency and power density are required. This paper proposes an unregulated LLC full-bridge operating at resonant frequency to obtain a constant gain at all loads. The first harmonic approximation (FHA) model is not accurate enough to estimate the voltage gain in converters with high parasitic resistance. A modified FHA model is proposed for voltage gain analysis, and time-based models are used to calculate the instantaneous current required for the ZVS transition analysis. A method using charge instead of current is proposed and used for this ZVS analysis. Using this method, an auxiliary circuit is proposed to achieve complete ZVS within the whole load range, avoiding a gapped transformer design and increasing the efficiency and power density. A 28 Vdc output voltage prototype, with 10 kW peak output power, has been developed to validate the theoretical analysis and the proposed auxiliary circuit. The maximum efficiency (96.3%) is achieved at the nominal power of 5 kW.

scholarly journals Analysis and Pareto Frontier Based Tradeoff Design of an Integrated Magnetic Structure for a CLLC Resonant Converter

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1756
Author(s):  
Gang Wang ◽  
Qiyu Hu ◽  
Chunyu Xu ◽  
Bin Zhao ◽  
Xiaobao Su
Keyword(s):  
Magnetic Structure ◽  
Power Density ◽  
High Efficiency ◽  
Pareto Frontier ◽  
Optimization Procedure ◽  
Magnetic Core ◽  
Pareto Optimization ◽  
High Power Density ◽  
Resonant Converter ◽  
Conduction Loss

This paper proposes an integrated magnetic structure for a CLLC resonant converter. With the proposed integrated magnetic structure, two resonant inductances and the transformer are integrated into one magnetic core, which improves the power density of the CLLC resonant converter. In the proposed integrated magnetic structure, two resonant inductances are decoupled with the transformer and can be adjusted by the number of turns in each inductance. Furthermore, two resonant inductances are coupled to reduce the number of turns in each inductance. As a result, the conduction loss can be reduced. The trade-off design of the integrated magnetic structure is carried out based on the Pareto optimization procedure. With the Pareto optimization procedure, both high efficiency and high-power density can be achieved. The proposed integrated magnetic structure is validated by theoretical analysis, simulations, and experiments.

scholarly journals Near-field thermophotovoltaics for efficient heat to electricity conversion at high power density

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rohith Mittapally ◽  
Byungjun Lee ◽  
Linxiao Zhu ◽  
Amin Reihani ◽  
Ju Won Lim ◽  
...  
Keyword(s):  
Power Density ◽  
High Power ◽  
High Efficiency ◽  
Near Field ◽  
Electrical Power ◽  
Photovoltaic Cells ◽  
High Power Density ◽  
Pv Cell ◽  
Electrical Power Output ◽  
Power Densities

AbstractThermophotovoltaic approaches that take advantage of near-field evanescent modes are being actively explored due to their potential for high-power density and high-efficiency energy conversion. However, progress towards functional near-field thermophotovoltaic devices has been limited by challenges in creating thermally robust planar emitters and photovoltaic cells designed for near-field thermal radiation. Here, we demonstrate record power densities of ~5 kW/m2 at an efficiency of 6.8%, where the efficiency of the system is defined as the ratio of the electrical power output of the PV cell to the radiative heat transfer from the emitter to the PV cell. This was accomplished by developing novel emitter devices that can sustain temperatures as high as 1270 K and positioning them into the near-field (<100 nm) of custom-fabricated InGaAs-based thin film photovoltaic cells. In addition to demonstrating efficient heat-to-electricity conversion at high power density, we report the performance of thermophotovoltaic devices across a range of emitter temperatures (~800 K–1270 K) and gap sizes (70 nm–7 µm). The methods and insights achieved in this work represent a critical step towards understanding the fundamental principles of harvesting thermal energy in the near-field.

scholarly journals On Performance of Sparse Fast Fourier Transform Algorithms Using the Aliasing Filter

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1117
Author(s):  
Bin Li ◽  
Zhikang Jiang ◽  
Jie Chen
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
High Efficiency ◽  
Theory And Practice ◽  
Long Time ◽  
And Performance ◽  
Binary Tree Search ◽  
The One ◽  
Sparse Fast Fourier Transform ◽  
L1 And L2

Computing the sparse fast Fourier transform (sFFT) has emerged as a critical topic for a long time because of its high efficiency and wide practicability. More than twenty different sFFT algorithms compute discrete Fourier transform (DFT) by their unique methods so far. In order to use them properly, the urgent topic of great concern is how to analyze and evaluate the performance of these algorithms in theory and practice. This paper mainly discusses the technology and performance of sFFT algorithms using the aliasing filter. In the first part, the paper introduces the three frameworks: the one-shot framework based on the compressed sensing (CS) solver, the peeling framework based on the bipartite graph and the iterative framework based on the binary tree search. Then, we obtain the conclusion of the performance of six corresponding algorithms: the sFFT-DT1.0, sFFT-DT2.0, sFFT-DT3.0, FFAST, R-FFAST, and DSFFT algorithms in theory. In the second part, we make two categories of experiments for computing the signals of different SNRs, different lengths, and different sparsities by a standard testing platform and record the run time, the percentage of the signal sampled, and the L0, L1, and L2 errors both in the exactly sparse case and the general sparse case. The results of these performance analyses are our guide to optimize these algorithms and use them selectively.

Sign in / Sign up

Export Citation Format

Share Document