Design and analysis of a 35 kVA medium frequency power transformer with the nanocrystalline core material

Balci, Selami; Sefa, İbrahim

doi:10.1016/j.ijhydene.2017.03.158

Cited by 28 publications

(13 citation statements)

References 11 publications

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“…With the FEA software developed in recent years, the magnetic behavior, power losses and magnetic noises of the transformers can be determined [3]. It is seen that results obtained from FEA software by using actual dimensions and material specifications are closer to the obtained results from the actual transformer [12]. Thus, in the design phase, the initial flux distributions and the core losses, as well as the current density distributions of the windings and the winding losses are predicted, thus, cost of the optimization process and time period required for the production process are reduced [13].…”

Section: Introductionmentioning

confidence: 72%

“…where δ [m] is the core material thickness, ρ e [Ωm] -the resistivity of the core material, γ c [kgm -3 ] -the mass density of the core material, K f -the form factor of the transformer excitation voltage. The form factor of the transformer excitation voltage is selected 4.44 for sinusoidal excitation and 4 for rectangular wave excitation [12].…”

Section: Transformer Losses Under the Non-linear Loadsmentioning

confidence: 99%

“…Thus, the heat transfer with different properties is formed between the transformer core, windings, insulation materials and other components. Equations (8)-(10) define the mathematical expressions for heat transfer by conduction, convection and radiation, respectively [12]:…”

Section: Modeling Of the Transformer Heat Transfermentioning

confidence: 99%

“…where C is the thermal capacity, Q -the volumetric density of the heat source, h c -the actual heat transfer coefficient by convection, T [°C] -the temperature of the surface heating up, T a [°C] -the temperature at a point far from the surface, γ -the Stefan-Boltzman constant, and ε -the thermal radiation coefficient [12].…”

Section: Modeling Of the Transformer Heat Transfermentioning

confidence: 99%

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Thermal behavior of a three phase isolation transformer under load conditions with the finite element analysis

Balci

2020

THERM SCI

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Transformers are generally designed to operate under the sinusoidal excitation and the method called classical design method is used in design process. Nevertheless, they have to operate under the partly or fully non-linear excitation because of the increasing amount of the non-linear loads such as rectifiers, electric motor drivers, compact fluorescent lamps, computers, etc. Non-linear loads cause abnormal temperature rise both in the core and in the windings of the transformer which are designed for sinusoidal excitation. Nowadays in the virtual environment provided by the electromagnetic design software, transformers can be easily modeled with the finite element method for any type of non-linear loads or excitations. In this study, 3-D electromagnetic and thermal modeling of the isolation transformer at a certain rated power level have been carried out. Then, the core and the winding temperatures of the transformer have been comparatively reported under the linear and non-linear load conditions. Besides, forced air-cooling method of the transformer has been tested with the CFD. This study has shown that, transformer temperature can be kept in the safe operating region in any type of load by deciding the fan speed providing the required air-flow according to the transformer temperature.

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Section: Introductionmentioning

confidence: 72%

Section: Transformer Losses Under the Non-linear Loadsmentioning

confidence: 99%

Section: Modeling Of the Transformer Heat Transfermentioning

confidence: 99%

Section: Modeling Of the Transformer Heat Transfermentioning

confidence: 99%

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Thermal behavior of a three phase isolation transformer under load conditions with the finite element analysis

Balci

2020

THERM SCI

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“…Lately, MFT designs for a frequency range from 600 Hz [9] to 20 kHz [10] have been proposed using different core materials [11,12] such as ferrites [10], nanocrystalline [13,14], silicon steel [9,15] and amorphous materials [16]. Each material has distinctive characteristics.…”

Section: Introductionmentioning

confidence: 99%

Nanocrystalline and Silicon Steel Medium-Frequency Transformers Applied to DC-DC Converters: Analysis and Experimental Comparison

et al. 2019

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High performance, highly efficient DC-DC converters play a key role in improving the penetration of renewable energy sources in the context of smart grids in applications such as solid-state transformers, built-in power drives in electric vehicles and interfacing photovoltaic and wind-power systems. Advanced medium-frequency transformers (MFTs) are fundamental to enhance DC-DC converters and determining its behavior, therefore MFT design procedures have become increasingly important in this context. This paper investigates which type of core material, between nanocrystalline and silicon steel, has the best properties for designing MFTs for distinct applications. Unlike to other proposals, in this work, two 1 kVA-120 V/240 V-1 kHz lab MFT prototypes, with a different type of core material, are developed for the purpose of comparing its physical characteristics, behavior, and performance under real-life conditions. A final section, the experimental results show that the nanocrystalline MFT has greater power density and efficiency. The results of this work introduce nanocrystalline MFTs as an option in a wider range of applications in niches in which other materials are currently used.

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Analysis of integrated magnetics for input series output series DC–DC converter

Ali,

Zheng,

Khan

et al. 2024

Circuit Theory & Apps

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SummaryMulti‐module isolated converters (MMICs) find extensive applications in various DC–DC applications owing to their exceptional features of galvanic isolation, bidirectional power flow, high‐power density, and enhanced efficiency. However, voltage and current sharing among the converter modules are the most significant issues in MMICs. This paper proposes multiport integrated‐magnetics transformers (MpIMTs) which address the input–output DC‐link voltage imbalances within an ISOS converter. The proposed transformers ensure the input voltage sharing (IVS) and output voltage sharing (OVS) through balancing windings within their structures, thus substitutes the complicated active control scheme with the balancing winding. Besides, the input side and output side modules are decoupled from each other; thus, the impact of parameters variation and intermodule energy transfer during a transient of one side does not reflect to the other side. These properties are achieved by proposing a custom‐designed core and an off the shelf available U‐core assembled MpIMTs. The magnetic and electrical equivalent circuit along with the design criteria of the balancing winding are also presented. Furthermore, the paper includes the comparative analysis of the proposed transformers which reveals that while the U‐core MpIMT offers simplified construction, it comes at the expense of slightly reduced efficiency compared with the custom‐designed MpIMT. Finally, the proposed U‐core MpIMT is validated through a laboratory prototype.

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Design and analysis of a 35 kVA medium frequency power transformer with the nanocrystalline core material

Cited by 28 publications

References 11 publications

Thermal behavior of a three phase isolation transformer under load conditions with the finite element analysis

Thermal behavior of a three phase isolation transformer under load conditions with the finite element analysis

Nanocrystalline and Silicon Steel Medium-Frequency Transformers Applied to DC-DC Converters: Analysis and Experimental Comparison

Analysis of integrated magnetics for input series output series DC–DC converter

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