Since TRANSFORMERs are one of the most important and most used equipment in power network, investigating the factors which affect the loss of these equipments is of particular importance. Nowadays AMORPHOUS metal CORE TRANSFORMERs have a significant place in today power market, since they exhibit 60-70% lower no-load losses compared to the Silicon crystalline steel CORE TRANSFORMERs. In order to enhance the design and cost and also to shorten the time to produce AMORPHOUS metal CORE TRANSFORMERs, numerical analysis of the no-load as well as load conditions are of paramount importance and hence should be considered. On the other hand, temperature is one of the important and effective factors in TRANSFORMER life, because increasing the TRANSFORMER temperature leads to reduction of its rated life. In this paper, a 100 kVA unit TRANSFORMER has been simulated by coupling ANSYS Maxwell and ANSYS FLUENT softwares and no-load and load losses are investigated. The results show that AMORPHOUS CORE TRANSFORMER compared to Silicon Crystalline Steel CORE TRANSFORMER reduce no-load losses about 65 percent. Furthermore, thermal analysis shows AMORPHOUS CORE TRANSFORMER has lower temperature compared to the Silicon CORE TRANSFORMER in no-load conditions.

A wind turbine TRANSFORMER (WTT) is designed using a 3D wound CORE while the TRANSFORMER’s total owning cost (TOC) and its inrush current performance realized as the two objective functions in a multi-objective optimization process. Multi-objective genetic algorithm is utilized to derive Pareto optimal solutions. The effects of inrush current improvement on other operating and design parameters of the TRANSFORMER such as: losses, dimensions, and weights are investigated. An approach is presented to select one design from optimal Pareto solutions based on relative improvement of the inrush current performance. Finally, this multi-objective optimum wind turbine TRANSFORMER design is compared with an optimum TRANSFORMER design obtained when just TOC is the objective function.

The aim of this study is to examine and analyze the axial and radial forces, electromagnetic forces (EMFs) acting on the low and high-voltage windings of an AMORPHOUS CORE TRANSFORMER via the two different approaches: an analytic approach and a 3-D finite element method (FEM). Firstly, the analytic method is proposed to analyze the distribution of leakage magnetic field in the magnetic circuit and the forces acting on the TRANSFORMER windings. The FEM embedded in the Ansys Maxwell tool is then proposed to compute and simulate the axial and radial forces under three different operating conditions: no-load, rated full-load, and short-circuit. The obtained results from two different methods such as the rated voltage, rated current, short-circuit current, axial and radial forces and EMFs in the low and high-voltage windings are finally compared to illustrate an agreement of methods. The validation of the methods is applied on a three-phase AMORPHOUS CORE TRANSFORMER of 1600kVA-22/0.4kV.

High-frequency power TRANSFORMERs are available in electronic power converters for many applications such as power transmission, renewable energy systems, and power supplies. Magnetic materials production technologies such as ferrite, AMORPHOUS, and high-frequency nanocrystals are used to miniaturize TRANSFORMERs and optimize the design. In this paper, the design of a high-frequency TRANSFORMER based on the finite element method (FEM) is proposed, and a frequency TRANSFORMER above 5 kV and a power of 100 watts with a ferrite CORE is designed for use in high voltage charges in pulse power technology. After the calculation step, the three-dimensional model of the TRANSFORMER with the nonlinear CORE is created with Maxwell finite element analysis software and then the simulations of the electromagnetic model of the TRANSFORMER with electronic power converter circuit are implemented with the help of Simplorer software for operating conditions. Also, the efficiency of the TRANSFORMER, the exact equivalent circuit of the TRANSFORMER, and the flux distribution in the TRANSFORMER CORE are obtained. In addition, TRANSFORMER samples have been fabricated and tested. The data obtained from the finite element method are compared with the analytical and laboratory methods. The results show that the finite element method seems more accurate compared to the analytical methods. Due to the importance and complexity of designing high-frequency TRANSFORMERs, using this method can provide advantages and simplicity for TRANSFORMER designers for parameter calculation and optimal design.

In this paper, a new high step-up current-fed LLC resonant DC-DC converter with a center-tapped TRANSFORMER is proposed. By selecting the switching frequency to be lower than, but near to, the series resonant frequency of the LLC resonant tank, soft-switching operation of all semiconductors, i.e., zero voltage switching (ZVS) turn-on of power MOSFETs and zero current switching (ZCS) turn-off of diodes is achieved. This leads to lower electromagnetic interference (EMI) and lower switching losses and improves the converter efficiency. An interleaved structure is used at the primary side. Thus, input current ripple is smaller, and its frequency is twice the switching frequency. Consequently, a smaller input filter is necessary in practice. The converter with 1.2 kW output power and 760 V regulated output voltage with 80-200 V input voltage variations is simulated. The output voltage is regulated by using asymmetric pulse width modulation (APWM) at 200 kHz switching frequency. Finally, a 700-W prototype has been implemented and experimental results are also presented to verify the simulation results.