Comprehensive Analysis of Electric Field Characteristics for Multi-Winding Medium Frequency Transformer

The multi-winding medium frequency transformer (MMFT) has attracted widespread attention, since its application in power electronic transformers can simplify the system structure and reduce the volume and weight. However, the special working conditions of MMFT due to high voltage and high power density increase the difficulty of insulation design for MMFT. For this issue, this paper presents a comprehensive analysis of electric filed characteristics for MMFT. First, the electric field model of MMFT is established using the 2-D finite element method. Based on it, the influences of connection mode, core structure, and hollow winding on the electric field characteristics of MMFT are studied, including the overall electric field distribution, maximum electric field intensity, and the electric field intensity along a fixed path. The results show that there are differences in the maximum electric field intensity for different connection modes and different core structures, which provides references for MMFT insulation design. The proposed modeling method and analysis results in this paper are important for insulation improvement of MMFT.

Parametric Analysis of an Optical Log-Spiral Nano-Antenna for Infrared Energy Harvesting

In this paper, we present the design of a spiral nano-antenna dedicated to infrared energy harvesting at 28.3 THz. A comprehensive, detailed parametric study of key parameters such as the initial angle at the origin arm, width of the spiral arms, gap between the two arms, thickness of substrate, length of substrate, thickness of patch and number of turns of the nano-antenna is also presented and discussed in order to harvest maximum electric field in the gap of the spiral antenna in the frequency range of 28 – 29 THz. The maximum electric field is simulated at 28.1, 28.3, 28.5 and 28.7 THz. A variation of the electric field of the antenna for different value of incident wave angle at the resonance frequency 28.3 THz has been simulated. The main advantages of the studied structure are its ability to reach high confined electric field within its gap, its wideband behavior around the operating frequency 28.3 THz, and its insensitivity to polarization of incident electromagnetic waves.

Pemodelan dan Simulasi Medan Listrik pada Jaringan Distribusi 20 kV Double Feeder Konstruksi 3B

ABSTRAKPeralatan listrik yang bertegangan dapat menyebabkan medan listrik di sekitar peralatan listrik, mengetahui besaran nilai medan listrik menjadi hal yang penting, untuk mengetahui paparan medan listrik pada lingkungan sekitar. Metode numerik memainkan peran penting dalam perhitungan medan listrik untuk studi medan listrik yang terkait dengan aplikasi tegangan tinggi. Charge Simulation Method merupakan salah satu metode numerik yang dapat digunakan sebagai pendekatan untuk menghitung distribusi medan listrik dan medan magnet pada penghantar yang bertegangan. Paper ini membahas pemodelan medan listrik di sekitar jaringan distribusi double feeder kontruksi 3B dengan menggunakan Matlab untuk mengetahui jarak ambang batas aman pengaruh medan listrik bagi manusia. Simulasi dilakukan pada setiap fasa konduktor dengan jarak ukuran setiap fasa diatur sesuai kontruksi yang diterapkan pada PLN. Hasil penelitian menunjukan bahwa simulasi menggunakan MATLAB pada distribusi 20 kV double feeder kontruksi 3B, hasil medan listrik maksimal pada ketinggian 1 meter atau pada ketinggian rata-rata manusia, memiliki besaran 1,54 kV/meter. Besaran medan ini lebih kecil dari batas minimal standar WHO dan SNI, sehingga masih masuk batas aman.Kata kunci: medan listrik, charge simulation method, jaringan distribusi, distribusi kontruksi double feeder 3BABSTRACTElectrical equipment can cause an electric field around the equipment, knowing the value of the electric field becomes important, to determine the exposure of the electric field to the surrounding environment. Numerical methods play an important role in the computation of electric fields for the study of electric fields related to high voltage applications. Charge Simulation Method is one of the numerical methods that can be used as an approach to computate the distribution of electric and magnetic fields in a live conductor. This paper discusses the modeling of the electric field around the distribution double feeder 3B construction network using Matlab to determine the safe threshold distance of the influence of the electric field for humans. Simulation experiments are carried out on each phase of the conductor with the distance of each phase adjusted according to the applied construction to PLN. The results showed that the simulation using MATLAB on the distribution of 20 kV double feeder construction of 3B, value of the maximum electric field at an altitude of 1 meter or at an average height of humans, has a magnitude of 1.54 kV / meter. The magnitude of this field is smaller than the minimum WHO and SNI standards, so it is still safe for humans.Keywords: electric field, charge simulation method, distribution network, 3B double feeder construction distribution

Effect of Loudspeakers on the In Situ Electric Field in a Driver Body Model Exposed to an Electric Vehicle Wireless Power Transfer System

This study computationally evaluates the effect of loudspeakers on the in situ electric field in a driver body model exposed to the magnetic field from a wireless power transfer (WPT) system in an electric vehicle (EV), one with a body made of carbon fiber reinforced plastic (CFRP) and the other made with aluminum. A quasi-static two-step approach was applied to compute the in situ electric field. The computational results showed that the magnetic field distribution generated by the WPT is significantly altered around the loudspeakers, and shows obvious discontinuity and local enhancement. The maximum spatial-average magnetic field strength in the driver’s body was increased by 11% in the CFRP vehicle. It was 2.25 times larger than the reference levels (RL) prescribed in the International Commission of Non-Ionizing Radiation Protection (ICNIRP) guidelines in 2010. In addition, we found that the in situ electric field computed by the line- and volume-averaging methods were stable if the top 0.1% voxels are excluded. The maximum value was well below the basic restriction (BR) of the ICNIRP guidelines. Nevertheless, the presence of the loudspeaker led to increments in the electric field strength in parts of the human body, suggesting the potential influence of permissible transmitting power in the WPT system. The maximum electric field strength in the thigh and buttock with the woofer, increased by 27% in the CFRP vehicle. The arm value was up to 3 times higher than that obtained without the tweeter in the aluminum vehicle. Moreover, this study found that the maximum electric field strength depended on the location of the loudspeaker with respect to the WPT system and the separation from the driver model. Therefore, the loudspeaker should be considered when evaluating the maximum in situ electric field strength in the vehicle body design stage.

Power Transformer’s Electrostatic Ring Optimization Based on ANSYS Parametric Design Language and Response Surface Methodology

In this paper, in view of the low efficiency of the traditional finite element method (FEM), which has been widely used in the insulation design of power transformers, the response surface methodology (RSM) is proposed to optimize the insulation structure of a power transformer electrostatic ring. Firstly, the power transformer model was built using the ANSYS parametric design language (APDL) to realize the automatic pre-processing of numerical calculation. Then with the objective of reducing the maximum electric field intensity, the Taguchi method was used to select the parameters that have a greater impact on the maximum electric field intensity, by which the subsequent optimization process could be effectively simplified. The test points were constructed by the central composite design (CCD) and a response surface model was established by the mutual calls of MATLAB and ANSYS. Finally, the variance analysis, diagnostic analysis, and significance test of regression were carried out to obtain the final response surface model. By comparing the result of RSM with that of FEM, we can find that the results obtained by the two methods are consistent and the maximum electric field strength is obviously reduced. The RSM is more systematic and convincing, which improves the optimization efficiency and provides a reliable and fast way for the optimization of power transformers.

A Study on Physically Based Maximum Electric Field Modeling Used for HCI Induced Degradation Characteristic of LDMOS

This paper describes a physically based maximum electric field model of laterally diffused MOSFET (LDMOS) transistors under the condition of high current injection effect used for reliability and aging simulations. LDMOSFETs work under high-voltage and large-current biases, where electric field increases with the biases at the gate edge. We present formulations, implementations into SPICE simulators and measurement verifications of our physically based maximum electric field model.